WO1999003564A2 - Method and apparatus for oxidizing no to no2 and apparatus and method for generating ozone - Google Patents

Abstract

Apparatus for oxidizing NO to NO2 in a gas stream using ozone gas comprising piping for the gas stream, tubing for the ozone gas, and pitot tubes; the piping for the gas stream including at least one hole defining an opening in the gas stream piping, an ozone carrying tube extending from outside the gas stream pipe through the opening into the interior of the gas stream pipe, an axially disposed pitot tube extending in the direction of flow of the gas stream connected to the end of the ozone carrying tube, said pitot tube adapted to aspirate ozone into the gas stream.

Description

0₃ ASPIRATOR

To fully understand the Ozone (O₃) Aspirator we must look at three technologies:

(1 ) Flow Through Nozzle Technology, (2) lonization Technology, (3) Oxidation - Reduction Reactions.

Flow Through Nozzles (Ref. Fundamentals of Thermodynamics)

This technology deals with the thermodynamic aspects of one- dimensional flow through nozzles. In addition, the momentum equation for the control volume is developed and applied to these same problems. The sonic velocity is defined in terms of thermodynamic properties, and the importance of the mach number as variable incompressible flow is noted.

(A) Dealing with problem involving flow, many discussions and equations can be simplified by introducing the concept of the isentropic stagnation state and the properties associated with it. The isentropic stagnation state, is the state a flowing substance would attain if it underwent a reversible adiabatic deceleration to zero velocity. This state is designated in topic with the subscript 0. From the first law for a steady-state, steady-flow process we conclude that: h +V² = h₀

2

The actual and the isentropic stagnation states for a typical gas or vapour are shown on the h - s diagram of Figure 1. Sometimes it is advantageous to make a distinction between the actual and the isentropic stagnation states. The actual stagnation state is the state achieved after an actual declaration to zero velocity, and there maybe irreversibility's associated with the declaration process. Therefore, the term stagnation property is sometimes reversed for the properties associated with the actual state, and the term total property is used for the isentropic stagnation state.

It is evident from Figure 1 the enthalpy is the same for both the actual(1 ) and isentropic stagnation states(2). Therefore, for an ideal gas, the actual stagnation temperature is the same as the isentropic stagnation temperature.

However, the actual stagnation pressure(3) may be less than the isentropic stagnation pressure(4) and for this reason the term total pressure(5) has particular meaning compared to the actual stagnation pressure.

EXAMPLE:

Air flows in a duct at a pressure of 150 Kpa with a velocity of 200 m/s.

The temperature of the air is 300 K. Determine the isentropic stagnation pressure and temperature.

Analysis and Solution:

If we assume that the air is an ideal gas with constant specific heat as given in thermodynamic tables, the calculation is as follows: ² =h₀-h = c_Po(τ₀-τ)

2

.-. (200)²= 1.0035 (T₀ -300) 2X1000

Λ T₀=319.9K

The stagnation pressure can be found from the relation:

I_O = (E_O)(K- 1)/K T P

•^•• 319.9 = (P„) 0.286 300 150

.-. P₀= 187.8 Kpa

(B) It will be advantageous to develop the momentum equation for the control volume. Newton's second law states that the sum of the external forces acting on a body in a given direction is proportional to the rate of change of momentum in the given direction.

∑ Fx oc dfmV dt

For the system of units used, the proportionality can be written directly as an equality:

y Fx - d(mVx) dt

This equation has been written for a body of fixed mass, or in thermodynamic parlance, for a control mass. We now proceed to write the momentum equation for a control volume, and follow a procedure similar to that used in writing the continuity equation and the first and second laws of thermodynamics for a control volume.

Consider the control mass and control volume shown in the equation above. Let the control volume be fixed relative to its co-ordinate frame. During the time interval δt, the mass δm, enters the control volume with a velocity (V_r); and velocity components (V_x); (V_y); and (V₂)_|. During this same time interval the mass δm_e leaves the control volume, with velocity (V_r)_e and velocity components (V_x)_e, (V_y)_e. If we write the _x momentum equation for the control mass during this time interval we have:

(∑F_X)_AV = ΔχmV_x} = (mY_x)₂ - (mV_x), δt δt

Let (mV_x)_t = x momentum in the control volume at time t

(mV_x)_t + δt = x momentum in the control volume at time t

+ δt Then (mV_x)., = (mV_x)_t + (V_x)_| δlTl_j = x momentum of control mass at time t

(mV_x)₂= (τrV_x)_t + δ, + (V_x)_eδm_e = x momentum of control mass at time t

+ δt

It follows that:

(mV_x)₂ - (mV_x)₁ = [(mV_x)t +δt - (V_x) +] + [(mV_x)_e δm_e -(V_x),δmJ

The first bracketed term on the right side of equation represents the change of x momentum within the control volume during the time interval δt, and the second bracketed term in that equation represents the x- directional momentum flow across the control surface during δt. Now, diving equation by δt and substituting the first equation:

(∑F_X)_AV = (my_x)_t + δt - (mV_x)_t (Vχ)eδme - (Vx)iδmj δt δt

We now establish the limit for each of the terms in this expression as δt →O

LIM (∑F_X)_AV = ∑F_X δt →O

LIM KπΛΛ + t δt - (mV„) +] = d (mVΛc.v. δt →O δt dt

Thus, as δt →O, we have a rate form of the momentum equation for the control volume.

∑F_X = gXmY_x)G + =∑m_e(V_e)_x -∑m_l(V_l)_x dt

We will be concerned primarily with steady-state, steady-flow process in which there is a single flow with uniform properties into the control volume, and a single flow with uniform properties out of the control volume.

(C) A nozzle is a device in which the kinetic energy of a substance is increased in an adiabatic process. This increase involves a decrease in pressure and is accomplished by the proper change in flow area. A diffuser is a device that has the opposite function, namely, to increase the pressure by decelerating the substance. To minimize words both nozzles and diffusers will be used as the term nozzle. Consider a simple nozzle, and assume an adiabatic, one dimensional, steady-state, steady-flow process of an incompressible substance. From the continuity equation we conclude that: m_{e =} , m, = pA,V, = p _ev_e

OR = v_e

A^' _e v^~

The first law for this process is: h_e - i + Y_eiΛ i² + (z_e - _Zi)g = 0 2 From the second law we conclude the S_e > S_j, where the equality holds for a reversible process. Therefore, from the relation T ds = dh - vdP we conclude that for the reversible process: _e - h_s = j* vdP

If we assume that the substance is incompressible the equation above can be integrated to give:

Substituting this we have v(P_e - Pi) + . XY , + (Zβ - Zi)g = 0 2 This is the Bernoulli equation, which was derived from the equations for the reversible adiabatic, one-dimensional, steady-state, steady flow of an incompressible substance through a nozzle the Bernoulli equation represents a combined statement of the first and second laws of thermodynamics.

When a pressure disturbance occurs in a compressible substance, the disturbance travels with a velocity that depends on the state of the substance. A sound wave is a very small pressure disturbance; the velocity of sound, also called the sonic velocity is an importance parameter in compressible- substance flow. We proceed now to determine an expression for the sonic velocity of an ideal gas in terms of the properties of the gas. Let a disturbance be set-up by the movement of a piston at the end of the tube illustrated in Figure 2 . A wave(6) travels down the tube(7) with a velocity c(8), which is the sonic velocity.

Assume that after the wave(6) has passed the properties of the gas(9) have changed an infinitesimal amount and that the gas(9) is moving with the velocity dV(10) toward the wave front. (11 ) is a process shown from the point of view of an observer who travels with the wave front. Consider the control the surface(12) shown in Figure 3. From the first law for this steady-state, steady flow process we can write: h + c² = (h + dh) + (c - dVV²

2 2 dh - cdV = 0

From the continuity equation we can write:

c dp - pdV = 0

Consider also the relation between properties: T ds = dh - dP P

If this process is isentropic, ds = 0 and this equation can be combined with the above to give the relation: dP - c dv = 0 P

This can be combined to give the relation: dP = c² dp

Since we have assumed the process to be isentropic this is better written as a partial derivative. [ τ_]_= c² ap _s

An alternate derivation is to introduce the momentum equation. PA - (P + dP) A = m (c - dV - c) = pAc (c - dV - c) dV = pc dP

On combining this quotation with a partial derivative we obtain:

T PI = c² dP _s

It will be of particular advantage to solve for the velocity of sound in an ideal gas. When an ideal gas undergoes an isentropic change of state, we found that, for this process, assuming constant specific heat: dP - K dP = 0 P P

OR

I5P1 = KP 3P _S p

Substituting this equation we have an equation for the velocity of sound in an ideal gas: c² =_kP P

Since for an ideal gas:

P = RT P

this equation may also be written: c² = KRT

The Mach number, M, is defined as the ratio of the actual velocity V to the sonic velocity c. M = V c

When M > 1 the flow is supersonic when M <1 the flow is subsonic; and when M = 1 the flow is sonic. The importance of the Mach number as a parameter in fluid-flow problems will be evident in the paragraphs that follow.

A nozzle or diffuser with both converging(13) and diverging(14) section is shown in Figure 4. The minimum cross-sectional area is called a throat(15).

Our first consideration concerns the conditions that determine whether a nozzle or diffuser should be converging(13) or diverging(14) and the conditions that prevail at the throat(15). For the control volume shown the following relations can be written:

First Law: dh + V dV =0

Property relation: T ds = dh - dP = 0

P

Continuity equation: p \V = m = constant dp + A + dV = 0 p A V

Combining Equations: dh = dP = -VdV

P

.-. dV = 1 dP PV Substituting: d/A = fdp - dvl = dp TdPl + 1 dP

>

A P V P dP pV^:

= - d£ [dp - ^: dP [ -_L + P dP V² p (dP/dp) V²

Since the flow is i isentropic: dP ^; = c² = y dp M²

and therefore, d_ = dP (1 - M²)

A pV²

This is a very significant equation, from it we can draw the following conclusions about the proper shape for nozzle and diffusers illustrated in Figure 5.

For a nozzle, dP < O, therefore, for a subsonic nozzle, M <1 , 6A

<O, the nozzle is converging(16).

For a supersonic nozzle, M > 1 <\A >0 and the nozzle is diverging(17).

For a diffuser, dP > 0. Therefore, for a subsonic diffuser, M <1 , δ A>0 and the diffuser is diverging(18).

For a supersonic diffuser, M >1 , όA <0 and the diffuser is converging(19).

When M = 1 , d>4 = 0, which means that sonic velocity can be achieved only at the throat of a nozzle or diffuser. We will now develop a number of relations between the actual properties, stagnation properties, and Mach number. These relations are very useful in dealing with isentropic flow of an ideal gas in a nozzle.

The relations between enthalpy, stagnation enthalpy and kinetic energy:

For an ideal gas with constant specific heat:

\/2 _ P IT τ\- 1/ΌT ΓT <Π

^^po ' c > > )

K-1 T

Since c² = = KRT

K-1 1

V² = M²= 2 L - 1] c² K- 1 T

For an isentropic process:

Therefore, p₀ = [1 + (K-1) M²] P 2

Po = [1 +(K-1)M²1^1/(K'1)

Values of P/P₀, p/p₀ and TT₀ are given as a function of M for the value K=1.40. The condition at the throat of the nozzle can be found by noting that M = 1 at the throat. The properties at the throat are denoted by an asterisk(*).

Therefore,

T* = 2 T₀ K + 1

p* = (_2_ )K/(κ- i) P₀ K + 1

Po K + 1

These properties at the throat of a nozzle when M = 1 are frequently referred to as critical pressure, critical temperature and critical density and the ratios given by the above equations are referred to as the critical temperature ratio, critical pressure ratios, and critical density ratio.

The table in Figure 6 provides these ratios for various values of K.

(F) We now turn our attention to a consideration of the mass rate of flow per unit area, m/A, in a nozzle. From the continuity equation we proceed as follows: m = pv = py κι₀

A RT KT„

= py K jo i

✓ KRT / R ✓ T ✓! 0

= PML K_ 1 + K___ M²

✓ T ¹ _n o /R / 2

The flow per unit area can be expressed in terms of stagnation pressure, stagnation temperature, Mach number, and gas properties. m = P_n K X M

A ST₀ , R (1 ₊ K_ M²) ^{(K + 1 )/2(K " 1)}

2

At the throat, M =1 , and therefore the flow per unit area at the throat, M/A^*, can be found by setting M = 1 in the above equation.

A^* /T₀ / R (K + 1 ) <^{K + 1)/2(K}- ¹⁾ 2

The area ratio A/A* can be obtained by:

Δ = l [(_2_ ) (1 + XL M²)]^{(K + 1 )/2(K " 1)} A* M K + 1 2

The area ratio A/A* is the ratio of the area at the point where the Mach number is M to the throat area, and values of A/A* as a function of Mach number. Figure 7 shows a plot of A/A*(20) vs M(21), which is in accordance with our previous conclusion that a subsonic nozzle is converging and a supersonic nozzle is diverging.

The final point to make regarding the isentropic flow of an ideal gas through a nozzle involves the effect of a varying back pressure (the pressure outside the nozzle exit) on the mass rate of flow. Consider first a convergent nozzle as shown in Figure 8, which also shows the pressure ratio P(22)/P₀(23) along the length of the nozzle. The conditions upstream are the stagnation conditions(24), which are assured to be constant. The pressure at the exit plane of the nozzle is designated P_E(25) and the back pressure P_B(26). Let us consider how the mass rate of flow m and the exit plane pressure P_E/P₀ vary as the back pressure P_B decreased. These quantities are plotted in Figure 9. When P_B/P₀ = 1 there is of course no flow, and P_E/P₀ =1 as designated by point a(27). Next let the back pressure P_B be lowered to the designated point b(28), so that P_B/P₀ is greater than the critical-pressure ratio. The mass rate of flow has a certain value and P_E = P_B The exit Mach number is less than 1. Next let the back pressure be lowered to the critical pressure, designated by point c(29). The Mach number at the exit is now unity, and P_E equals to P_B. When P_B is decreased below the critical pressure, designated by point d(30), there is no further increase in the mass rate of flow, and P_E remains constant at a value equal to the critical pressure, and the exit Mach number is unity. The drop in pressure from P_E to P_B takes place outside the nozzle exit. Under these conditions the nozzle is said to be choked, which means that for given stagnation conditions the nozzle is passing the maximum possible mass flow.

Consider next a convergent-divergent nozzle in a similar arrangement shown in Figure 10. Point a(31 ) designates the condition when P_B(32) - P₀(33) and there is no flow when P_B(32) is decreased to the pressure indicated by point b(34), so that P_B/P₀ is less than 1 but considerably greater than the critical-pressure ratio, the velocity increases in the convergent section(35), but M<1 at the throat(36). Therefore, the diverging section acts as a subsonic diffuser in which pressure increases and velocity decreases. Point c(37) designates the back pressure at which M = 1 at the throat, but the diverging section acts as a subsonic diffuser (with M =1 at the inlet) in which the pressure increases and velocity decreases. Point d(38) designates one other back pressure that permits isentropic flow, and in this case the diverging section acts as a supersonic nozzle, with a decrease in pressure and an increase in velocity. Between the back pressures designated by points c(37) and d(38), an isentropic solution is not possible, and shock waves will be present. When the back pressure is decreased below that designated by point d(38), the exit plane pressure P_E(39) remains constant, the drop in pressure from P_E(39) to P_B(32) takes place outside the nozzle. This is designated by point e(40).

(G) A shock wave involves an extremely rapid and abrupt change of state. In a normal shock this change of state takes place across a plane normal to the direction of the flow. Figure 11 shows a control surface(41 ) that include such a normal shock(42). We can now determine the relation that govern the flow. Assuming steady-state, steady-flow we can write the following relations, where subscripts x(43) and y(44) denote the conditions upstream(45A) and downstream of the shock, respectively. Note that no heat and work across the control surface(45B).

First law h_v + V χ = h,, + V —² y = rx ^■ox =h oy

Continuity equation: m = P_XV_X = p_yV_y A

Momentum equation:

A (P_x-P_y) = m(V_y-V_x)

Second law: Since process is adiabatic S_y - S_x > 0

The energy and continuity equations can be combined to give an equation that when plotted on the h - s diagram is called the Fanno line. Similarly, the momentum and continuity equation can be combined to give an equation the plot of which on the h - s diagram is known as the Rayleigh line. Both of these lines are shown on the h - s diagram of Figure 12. It can be shown that the point of maximum entropy on each line, points a and b, corresponds to M = 1.

The lower part of each line corresponds to supersonic velocities, and the upper part to subsonic velocities.

The two points where all three equations are satisfied are points x and y, x being the supersonic region and y in the subsonic region. Since the second law requires the S_y - S_x > 0 in an adiabatic process, we conclude that the normal shock can proceed only from x to y. This means that the velocity changes from supersonic (M > 1 ) before the shock to subsonic (M < 1 ) after the shock.

The equations governing normal Shock waves will now be developed. If we assume constant specific heats we conclude.

' ox ~ ' oy

That is, there is no change in stagnation temperature across a normal shock.

Introducing,

I_px = 1 + KX1 M² _X I__y = 1 + _____ M² _y T_x 2 T_y 2 and substituting we have

The equation of state, the definition of Mach number, and the relation c = ■ KRT can be introduced into the continuity equation as follows:

P_XV_X = p_yV_y But

ly = B_y V_y = P_yM_y C_y = P_yM_y I_y [Py]² [My]²

Tx PχV_χ PχM_xC_x P_XM/T_X P_v M_v

Combining the equations which involves combining the energy equation and the continuity equation, gives the equation of the Fanno line.

P_y = MV 1 + K - 1 Mi

P_x M_y/ 1 + K - 1 M_y ²

The momentum and continuity equation can be combined as follows to give the equation of the Rayleigh line.

P_x - P_y = M (v_y - V_x) = pyV²y - p_xV_x ² A

P_x + pxV_x ² = P_y + pyV_y ²

P_x + p_xM_x ²C_x ² = P_y + p_yM_y ²C_y ²

P_x + PχM_x ^g (KPT = P_y + Pjyiy²- (KRT_y) RT_X RT_y

P_x(1 + Km_x ²) = P_y(1 + Km_y ²)

Py= i__κm_x

The equation above can be combined to give the following equation relating M_x and M_y

2K M_x ² - 1

K - 1

Figure 13, table 1 gives the normal shock functions, which include M_y as a function of M_x. This table applies to an ideal gas with a value K = 1 .40. Note that M_x is always supersonic and M_y is always subsonic, which agrees with the previous statement that in a normal shock the velocity changes from supersonic to subsonic.

These tables also give the pressure, density, temperature and stagnation pressure ratios across a normal shock as function and the equation of state. Note that there is always a drop in stagnation pressure across a normal shock and an increase in the static pressure.

In conclusion, it should be pointed out that in considering the normal shock we have ignored the effect of viscosity and thermal conductivity, which are certain to be present. The actual shock wave will occur over some finite thickness.

However, the development as given here provides a very good qualitative picture of normal shocks, and also provides a basis for fairly accurate quantitative results.

(H) We now consider a vapour to be a substance that is in the gaseous phase but with limited superheat. Therefore, the vapour will probably deviate significantly from the ideal gas relations, and the possibility of condensation must be considered. One example is the flow of hot flue gas through the nozzle of a boiler breaching.

The principles that have been developed for the isentropic flow of an ideal gas apply also to the isentropic flow of a vapour. However, because the vapour deviates from the ideal gas relationships, the appropriate tables of thermodynamic properties must be used. Further, the possibility of condensation must be borne in mind as indicated in Figure 14. If flue gas expands isentropically from state 1 to state 2, and if equilibrium is maintained throughout the nozzle, condensation would begin at point 9, and at pressures below this mixture of liquid droplets and flue gas would be present. In an actual nozzle the formation of the liquid tends to be delayed due to an effect known as supersaturation.

Let us consider first the isentropic flow of flue gas in a nozzle without condensation. The value of the specific-heat ratio K for vapour varies, but K = 1.3 is a good approximation over a considerable range. Therefore, the critical pressure ratio, P*/P₀, can be found by relation.

P_ = ( 2 )^κ/κ"1 = 0.545 P₀ K + 1

Knowing therefore, the critical pressure ratio, the throat area for a given flow can be calculated in a similar manner. For vapour initially saturated the critical-pressure ratio is usually taken as:

P_ = 0.577 P₀

If the flow with initially saturated vapour is assumed to be isentropic there will be a certain amount of liquid entrained with the vapour. Calculation of throat and exit areas under most conditions is similar.

When the vapour flowing through a nozzle is initially superheated, there will be a certain point in the nozzle where the vapour becomes saturated. However, as noted in the above in connection with a discussion of metastable equilibrium, if the point at which condensation would occur under equilibrium conditions occurs in the divergent section of the nozzle, a condition of metastable equilibrium exists. That is the formation of droplets is delayed, and the vapour temperature is less than the saturation temperature for the given pressure. This is frequently referred to as supersaturation.

This phenomenon of super saturation is observed only in the diverging portion of the nozzle. In a nozzle in which supersaturation occurs the rate of mass flow might be slightly greater than that obtained in an isentropic flow without supersaturation.

Ozone (Ref.: Chemistry A Conceptual Approach (Fourth Addition), Fundamentals of Classical Thermodynamics, Foundations of Chemistry (Metric Addition)) (A) The existence of an element in more than one form in the same physical state is called allotropy, and the forms are called allotropes. A number of elements exhibit allotropy, for example, carbon, sulfur, and phosphorus. Oxygen exists in a triatomic form, ozone, in addition to the common diatomic modification.

The ozone molecule is diamagnetic and has an angular structure. Both oxygen-to-oxygen bonds have the same length (127pm), which is intermediate between the double-bond distance (1 10pm) and the single-bond distance (148pm). The molecule may be represented as a resonance hybrid:

Ozone is a pale blue gas with a characteristic odour; predictably, its density is 1 V2 times that of O₂. The normal boiling point of ozone is 1 12°C and the normal melting point is 193°C. It is slightly more soluble in water than is O₂.

Ozone is produced by passing a silent electric discharge through oxygen gas. The reaction proceeds through the dissociation of an O₂ molecule into oxygen atoms and the combination of an O atom with a second O₂ molecule. ¹/₂0₂ = → O ΔH = +247kJ 0 + 0₂= → 0₃ ΔH -105kJ

The energy released in the second step, in which a new bond is formed, is not sufficient to compensate for the energy required by the first step, in which a bond is broken. Hence, the overall reaction for the preparation of ozone is endothermic.

3/2 0₂ →0₃ ΔH = +142kJ

Ozone is highly reactive; it is explosive a temperature above 300°C or in the presence of substances that catalyses its decomposition. Ozone will react with many substances at temperatures that are not high enough to produce reaction with O₂. The higher reactivity of O₃ in comparison to O₂ is consistent with the higher energy content of O₃.

(B) lonization: We can consider the equilibrium of systems that are made up of ionized gases, or plasmas, a field that has been studied and applied increasingly in recent years. If we look at a chemical equilibrium, with a particular emphasis on molecular dissociation, as for example the reaction:

N₂ →\ 2N which occurs to an appreciable extent for most molecules only at high temperature, of the order of magnitude 3000 to 10,000k. At still higher temperatures, such as those found in electric arcs, the gas becomes ionized. That is, some of the atoms lose an electron, according to the reaction: N <-> N⁺ + e^" where N⁺ denotes a singly ionized nitrogen atom, one that lost one electron and consequently has a positive charge, and e^" represents the free electron. As the temperature rises still higher, many of the ionized atoms lose another electron, according to the reaction:

NX NX e^" and thus becomes doubly ionized. As the temperature continues to rise, the process continues until a temperature is reached at which time all the electrons have been stripped from the nucleus.

lonization generally is appreciable only at high temperature. However, dissociation and ionization both tend to occur to greater extents at low pressure, and consequently dissociation and ionization may be appreciable is such environments as the upper atmosphere, even a moderate temperatures.

The problems of analysing the composition in a plasma become much more difficult than for an ordinary chemical reaction, for in an electric field the free electrons in the mixture do not exchange energy with the positive ions and neutral atoms at the same rate that they do with the field. Consequently, a plasma in an electric field, the electron gas is not at exactly the same temperature as the heavy particles. However, for moderate fields, assuming a condition of thermal equilibrium in the plasma is a reasonable approximation, at least for preliminary calculations. Under this condition we can treat the ionization equilibrium in exactly the same manner as an ordinary chemical equilibrium analysis.

At these extremely high temperatures, we may assume that the plasma behaves as an ideal-gas mixture of neutral atoms, positive ions, and electron gas. Thus, for the ionization of some atomic species A, A → A⁺ + e^" We may write the ionization equilibrium equation in the form: K = y^±^_e- (J ) ¹⁺¹-¹ y_A P°

The ionization equilibrium constant K is defined in the ordinary manner:

In K = -ΔG° ^■RT

and is a function of temperature only. The standard-state Gibbs function change for reaction is found from: _ _ _

The standard-state Gibbs function for each component at the given plasma temperature can be calculated using the procedures of statistical thermodynamics, so that ionization-equilibrium constants can be tabulated as functions of temperature. Solution of the ionization-equilibrium equation is then accomplished in the same manner as for an ordinary chemical-reaction equilibrium.

Simultaneous reactions, such as simultaneous molecular dissociation and ionization reactions or multiple ionization reactions, can be analysed in the same manner as the ordinary simultaneous chemical reactions. In doing so, we again make the assumption of thermal equilibrium in the plasma, which, as mentioned before, is, in many cases, a reasonable approximation reasonable to assume that the formation of a positive gas ion is related to the ease with which an electron can be removed from a neutral gas atom. As stated earlier, the energy or work required to remove an electron from a gaseous atom is called the ionization energy, lonization energies may be determined spectroscopically or in some cases, by means of electrical measurements. The second method is easier to understand and is in depicted schematically in Figure 15. The schematic demonstrates bombarding gaseous atoms with electrons in a cathode-ray-like tube as voltage(46) is increased, electrons(47) from the filament F(48) gain sufficient energy to reach the plate P(49) and cause a rise the plate current 1(50), but do not have enough energy to dislodge the outer electron sodium atoms(51 ). No loss of energy is suffered in the elastic collisions(52) with the sodium atoms(51 ).

The kinetic energy of the bombarding electrons is related to and controlled by the applied voltage. Higher voltages increase the kinetic energies of the bombarding electrons. To determine the ionization energy of a gas atom, the voltage is increased until the kinetic energy of the bombarding electrons is equal to the energy needed to overcome the force of attraction between the nucleus and the easiest-to-remove electron of a gas atom. When this critical voltage is reached, positive gas ions are formed. The formation is signalled by a sudden change in current flow.

In theory, each atom has as many ionization energies as it has electrons. Past data show that the energy required to remove a second electron is always greater than that to remove the first. The removal of the first electron reduces the number of electrons and, consequently, the total electronic repulsion. This results in drawing the electron cloud closer to the nucleus as shown in Figure 16. Figure 16 illustrates the removal of an outer electron(53) from a sodium atom(54) reduces the electron-to-proton ratio(55), the total electron repulsion(56) and the radius of the particle(57).

It is more compact and, because of the smaller radius, each electron in the cloud is subjected to a greater force of attraction between an electron and its nucleus means that more energy is required to dislodge the electron, or to achieve ionization. Thus, the second ionization energy of a gaseous atom is always greater than the first. Oxidation - Reduction Reactions (Ref.: Foundation of Chemistry, Chemistry A Conceptual Approach, Fourth Edition)

(A) The term oxidation was originally applied to reactions in which substances combined with oxygen, and reduction was defined as the removal of oxygen from an oxygen - containing compound. The meanings of the terms have gradually been broadened. Today oxidation and reduction are defined on the basis of change in oxidation numbers.

Oxidation is the process in which an atom undergoes an algebraic increase in oxidation number, and reduction is the process in which an atom undergoes an algebraic decrease in oxidation number. On this basis, oxidation - reduction is involved in the reaction: o o → 4 + 2- s + o₂ so₂

The oxidation number of each type of atom is written above its symbol. Since the oxidation number of the s atom increases from 0 to 4+, sulfur is said to be oxidized. The oxidation number of the 0 atom decrease from 0 to 2^", and oxygen is said to be reduced. Oxidation - reduction is not involved in the reaction

4 + 2- 1 + 2- ~> 1+ 4 + 2-

SO₂ + H₂O H₂ SO₃

since no atom undergoes a change in oxidation number. It is apparent, from the way oxidation numbers are assigned, that neither oxidation nor reduction can occur by itself. Furthermore, the total increase in oxidation number must equal the total decrease in oxidation number. In the reaction of sulfur and oxygen, the sulfur undergoes an increase of 4. Each oxygen atom undergoes a decrease of 2. Since two 0 atoms appear in the equation, the total decrease is 4.

Since one substance cannot be reduced unless another is simultaneously oxidized, the substance that is reduced is responsible for the oxidation. This substance is called, therefore, the oxidizing agent or oxidant. Because of the interdependence of the two processes, the opposite is also true. The material that is itself oxidized is called the reducing agent or reluctant.

Therefore

0 ⁺ o — 4 + 2-

S O₂ SO₂ oxidized reduced reducing agent oxidizing agent

Equations for oxidation - reduction reactions are usually more difficult to balance than those for reactions that do not entail oxidation and reduction. Two methods are commonly used to balance oxidation - reduction equations: the oxidation - number method and the ion-electron method. For clarity, the physical state of the reactants and products will not be indicated in examples that will follow. In addition, the symbol H⁺, instead of H₃0⁺ or H⁺(aq), will be used.

There are three steps in the oxidation - number method of balancing oxidation - reduction equations. We will use the equation for the reaction of nitric acid and hydrogen sulfide to illustrate this method. The unbalanced expression for the reaction is:

HNO₃ + H₂S → NO + S + H₂O Step 1 : The oxidation numbers of the atoms in the equation are determined in order to identify those undergoing oxidation or reduction. Thus,

5+ 2- 2+ o

H N 0₃ + H₂S → NO + S + H₂0

Nitrogen is reduced (from 5+ to 2+, a decrease of 3), and sulfur is oxidized (from 2^" to 0, an increase of 2).

Step 2: Coefficients are added so that the total decrease and the total increase in oxidation number will be equal. We have a decrease of 3 and an increase of 2 indicated in the unbalanced expression. The lowest common multiple of 3 and 2 is 6. We therefore indicate 2HNO₃ and 2NO (for a total decrease of 6) and 3H₂S and 3S (for a total increase of 6). 2HN0₃ + 3H₂S → 2NO + 3S + H₂0

Step 3: Balancing is completed by inspection. This method takes care of only those substances that are directly involved in oxidation - number change. In this example, the method does not assign a coefficient to H₂O. We note, however, that there are now 8 H atoms on the left of the equation. We can indicate the same number of H atoms on the right by showing 4H₂O.

2HNO₃ + 3H₂S → 2NO + 3S + H₂O

The final, balanced equation should be checked to ensure that there are as many atoms of each element on the right as there are on the left.

The oxidation - number method can be used to balance net ionic equations, in which only those ions and molecules that take part in the reaction are shown. Consider the reaction between KCIO₃ and l₂. H₂0 + l₂ + CIO-₃ → IO ₃ + CI^" + H⁺

The K⁺ ion does not take part in the reaction and is not shown in the equation.

The steps in balancing the equation follow:

0 ) o 5+ 5+ 1- H₂0 + l₂ + CIO-₃ → IO-₃ + Cr + H⁺

(2) Each iodine atom undergoes an increase of 5 (from 0 to 5⁺), but there are two iodine atoms in l₂. The increase in oxidation number is therefore 10. Chlorine undergoes a decrease of 6 (from 5⁺ to 1^") the lowest common multiple of 6 and 10 is 30. Therefore, 3I₂ molecules must be indicated (a total increase of 30) and 5 CIO^" ₃ ions are needed (a total decrease of 30). The coefficients of the products, IO ₃ and CI^", follow from this assignment:

H₂0 + 3I₂ + 5CIO-₃ → 6IO-₃ + 5CΪ + H⁺

(3) If H₂O is ignored, there are now 15 oxygen atoms on the left and 18 oxygen atoms on the right. To make up 3 oxygen atoms on the left, we must indicate 3H₂O molecules. It often follows that the coefficient of H⁺ must be 6 to balance the hydrogen's of the H₂O molecules

3H₂0 + 3I₂ + 5CIO-₃ → 6IO ₃ + 5CI- + 6H⁺

An ionic equation must indicate charge balance as well as mass balance. Since the algebraic sum of the charges on the left (5 ) equals that on the right (5 ), the equation is balanced. Reaction in which electrons are transferred are clearly examples of oxidation - reduction reactions. In the reactions of sodium and chlorine, a sodium atom loses its valence electron to a chlorine atom. o o 1+ 1-

2Na + Cl₂ → 2Na + 2CI

For simple ions the oxidation number is the same as the charge on the ion. It follows, then, that electron loss represents a type of oxidation, and electron gain represents a type of reduction.

(B) Oxides and Oryacids of Nitrogen: Orides are known for every oxidation state of nitrogen from 1⁺ to 5⁺. Dimitrogen oxide (also called nitrous oxide), N₂O is prepared by gently heating molten ammonium nitrate. NH₄N0₃(l) → N₂0(g) + 2H₂0(g)

It is colourless gas and is relatively un-reactive. However, at temperatures around 500°C, dinitrogen oxide decomposes to nitrogen and oxygen; hence, N₂O supports combustion. Molecules of N₂O are linear, and the electronic structure of the compound may be represented as a resonance hybrid.

Dinitrogen oxide is commonly called "laughing gas" because of the effect it produces when breathing in small amounts. The gas is used as a general anaesthetic, and because of its solubility in cream, it is the gas used to charged whipped cream aerosol cans.

Nitrogen oxide (also called nitric oxide), NO, may be prepared by the direct reaction of the elements at high temperatures. N₂(g) + O₂(g) → 2NO(g) The reaction is endothermic (ΔH = +90 - 4KJ/MOL), but even at 3000°C the yield of NO is only approximately 4%. In a successful preparation the hot gases from the reaction must be rapidly cooled to prevent the decomposition of NO into nitrogen and oxygen. By this reaction, atmospheric nitrogen is fixed during lightning storms; this reaction also serves as the basis of the arc process of nitrogen fixation in which an electric arc is used to provide the high temperature necessary for the direct combination of nitrogen and oxygen. As a commercial source of NO, the arc process has been supplanted by the catalytic oxidation of ammonia from the Haber process.

The NO molecule contains an odd number of electrons, which means that one electron must be unpaired; for this reason, NO is paramagnetic.

The structure, however, is best described by molecular orbital theory, which assigns a bond order of 2¹2 to the molecule and indicates that the odd electron is a LT* orbital. The loss of an electron from NO produces the nitrosonium ion,NO⁺. Since the electron is lost from an anti bonding orbital, the NO⁺ ion has a bond order of 3 and the bond distance in NO⁺ (106pm) is shorter than the bond distance in the NO molecule (114pm). Ionic compounds of NO⁺ are known (for example, NO⁺, HSO₄, NO⁺ CIO^" ₄, and NO⁺BFV

Whereas odd electron molecules are generally very reactive and highly coloured, nitric oxide is only moderately reactive and is a colourless gas (condensing to a blue liquid and blue solid at low temperatures). In addition, NO shows little leniency to associate into N₂O₂ molecules by electron paring.

Nitrogen oxide reacts instantly with oxygen at room temperature to form nitrogen dioxide.

2NO(g) + O₂(g) → 2NO₂(g) Dinitrogen trioxide, N₂0₃, forms as a blue liquid when an equimolar mixture of nitric oxide and nitrogen dioxide is cooled to ^"20°C. NO(g) + N0₂(g) → N₂0₃(l)

The compound is unstable under ordinary conditions and decomposes to NO and NO₂. Both NO and NO₂ are odd-electron molecules.

The Invention (O, Aspirator)

The O₃ aspirator is a mechanical-electrical-chemical device that:

Option I - Introduces O₃ (ozone) into the Flow Through Nozzle where the ozone (O₃) is uniformly mixed with the Flue gas flow using the ozone (O₃) as an oxidizing agent to convert NO to NO₂ (oxidation), the ozone (O₃) is produced by a ozone generator supplied by others.

Option II - Generates a high voltage electrical arc (ionization) that produces ozone (O₃) which in turn is forced through a series of pitot tubes, to be introduced into the Flow Through Nozzle where the ozone (O₃) is uniformly mixed with the flue gas flow, using the ozone (O₃) as an oxidizing agent to convert NO to NO₂ (oxidation). Since in Option II O₃ is generated by the O₃ aspirator there is no need for an ozone generator by others.

OPTION I - The first step in making the O₃ aspirator is designing what we refer to as the spool piece which in normal terms is called the Flow Through Nozzle.

The Flow Through Nozzle illustrated in Figure 17 consist of Stainless Steel welded flange(58), stainless steel pipe(59), stainless steel tubing(60), orifice with enclosure(61 ) check valve stainless steel(62), manifold stainless steel(63), stainless steel tee's(64), stainless steel reducer(65), stainless steel needle valve(66) stainless steel vacuum breaker(67), pressure gauge(68), ozone generator connector(68) and stainless steel tube entry(70).

Welded Stainless Steel Flanges:

The usual form of a pipe joint is that made by bolting together flanges cast or forged integral with the pipe or fitting. The welded joint eliminates possibility of leakage between flange and pipe. It is very successful in lines or fittings subject to high temperature, pressures, and heavy expansion strains. Figure 18 shows a typical flange viewing from the side(71 ) and from the front(72). The flange fitting(73) is made of stainless steel and the grade complying with the ASTM (American Society for Testing and Materials) specifications recommended under these standards for the various pressures-temperatures ratings for which these standards are designed. The boltholes(74) are made from templates in multiples of four, in order that fittings maybe made to face in any quarter.

Bolthoies(74) are drilled 1/8" (0.32cm) larger in diameter than the normal size of bolt. The material of the bolts(75), nuts(76) and washers(77) are based on a high grade product equal to that given in the ASTM standard specifications for alloy-steel bolting material for high temperature service and with physical and chemical requirements in accordance with the tables given under ANSI B16.5-1981.

Various styles of finishes are used on the face of the flange(78), for the purpose of the retention of the gasket(79) used to make a tight joint. Those in general use are as follow: plain straight face, plain face corrugated or scored, male and female, tongue and groove, and raised face. Gaskets(79) used in this type of joint are either soft fibrous material or soft metal and extend from inside of the flange(78) to the boltholes(74). Only the small portion in contact with the narrow raised face is subjected to the compressive effect of the bolts(75).

Welded Stainless Steel Reducer:

Figure 19, illustrates a typical stainless steel reducer(80) which is used in most cases to reduce or increase the diameter of pipe, tee or elbow in a piping circuit. The reducer material and grade comply with the ASTM specifications recommended under the standards for the various pressure- temperature ratings. The Flow Through Nozzle uses two stainless steel reducers, one at the beginning to decease the pipe size and one to increase the pipe size further down the nozzle.

Welded Stainless Steel Pipe:

The term piping generally is broadly applied to pipe, fittings, valves and other components that convey liquids, gases, slurries etc. The term pipe is applied to tubular products of dimensions and materials commonly used for pipelines and connections, formerly designated as IPS (iron pipe size). The outside diameter of all weights and kinds of IPS pipe is of necessity the same for a given pipe size. Figure 20, illustrates a stainless steel pressure pipe(81 ) which is used for conveying fluids or gases at normal, subzero, or elevated temperatures, or acid conditions and/or pressures. Pressure pipe generally is hydrostatically tested at the mill.

Welded Stainless Steel Plate:

In Figure 21 , a stainless steel plate(82) is part of the Flow Through

Nozzle configuration. The stainless steel plate(82) is welded to the outside wall of the stainless steel pipe to support the stainless steel pipe and tubing(83). Stainless steel plate as well as the rest of the components of the Flow Through Nozzle are corrosion and heat resistant. The alloys in the material posses considerable ductility, ability to be worked hot or cold, and excellent corrosion resistant.

Pitot Tubes:

The word tube is generally applied to tubular products as utilized in boiler, heat exchangers, instrumentation and in the machine, aircraft, automotive and related industries. Unlike pipe and pressure tubes, mechanical tubing is generally classified by method of manufacture and the degree of finish. The pitot tubes are tapped and welded into the Flow Through Nozzle on the one side only, this will be explained latter in the process.

Stainless Steel Orifice:

Figure 22, illustrates orifice holder(84) made of stainless steel and grade complying to with the ASTM specifications, the orifιce(85) is stainless steel milled and drilled to the required job specifications, and a Teflon packing gland(86) that follow the ASTM guide lines for temperatures and pressures. The orifice holder(84) is tapped with female threads(87) so it can easily be screwed on to pipe ends.

Well-rounded orifices coefficients of discharge are known with more certainty than for sharp-edged orifices; an average value of 0.99 maybe assumed. If the orifice is to be used in a pipe the correction for velocity of approach is also known with considerable accuracy. The equation for flow is the same as for a sharp-edged orifice and the constants in Figure 23 apply for air.

Valves:

There are a few different types of valves that could be used on the O₃ aspirator assembly:

(A) Plug Valve: offers reliable shutoff, high flow capacity, and fast operation in a simple compact design. A quarter turn of the handle provides fully open to fully closed actuation. Intermediate positions allow forward flow throttling. Plug valves operate over wide pressure and temperature ranges. The design consists of three major components , as shown in Figure 24, the body(88), plug assembly(89) and handle(90). The plug(89) and three O-ring seals(91 ) are TFE coated to provide lubrication between the plug assembly(89) and the body bore(88). The valve features very low torque operation, even at maximum pressure rating. System pressure acts on equal body seal areas to prevent unbalanced plug load, which promotes safety.

(B) Multi-Service Ball Valves: perform on-off service where quick, positive shutoff or switching functions are required. The trunnion ball design provides a high degree of safety as well as excellent cycle life and low operating torque for service up to 10,000 psig (680bar). Figure 25, illustrates Directional Handle(92) which provides visual indication of stem position, bottom-loaded, blowout-proof stem(93) which provides enhanced safety, panel mounting(94) permits easy installation, spring-loaded peek seats(95) to ensure positive seating during pressure/temperature cycling, trunnion ball(96) using bearing support to minimize operating torque and seat wear at all service pressures, variety end connections(97) to add versatility with precision pipe end connections.

The ball valve is constructed of 316 stainless steel body and end screws, there is a wear resistant Xylan coating on the ball tronions and every valve is factory tested.

(C) Left Check Valves: Forward flow lifts the poppet which opens the valve. Back pressure seats the poppet against the orifice, eliminating reverse flow. The porting design directs reverse flow behind the poppet causing it to seat immediately. The valve is constructed of 316 stainless steel material.

Figure 26 illustrates union Bonnet(98) designed for safety, Metal to Metal Seal(99), stainless steel body(100), and end connections(101 ) for suitable fit.

Pressure Gauge:

The Bourdon-tube gauge is the most commonly used pressure device. Figure 27, consist of a flattened tube of spring bronze or steel bent into a circle(102). Pressure inside the tube tends to straighten it. Since one end of the tube is fixed to the pressure inlet(103), the other end moves proportionally to the pressure difference existing between the inside and outside of the tube. The motion rotates the pointer(104) through a pinion(105) and sector(106)mechanism. The pointer rotates on a scale indicator(107) design for each specific application.

OPTION II

Some of the components are similar to Option I, the illustration in

Figure 28 consists of stainless steel welded flange(108), stainless steel pipe(109) stainless steel tubing(110) stainless steel check valve(111) stainless steel reducer(112) circuit devices and system(113) stainless steel plate(114) sheet metal duct(115) variable speed fan(116).

Stainless steel flanges: described in Figure 17 Stainless steel pipe: described in Figure 20 Stainless steel tubing: described in Figure 20 Stainless steel check valve: described in Figure 26 Stainless steel reducer: described in Figure 18 Stainless steel plate: described in Figure 20

Circuit Devices and Systems:

Circuits in contrast to fields, the behaviour of a circuit can be completely described in terms of a single dimension, the position along the path constituting the circuit. In an electric circuit, the variables of interest are the voltage and current at various points, along the circuit. In circuits in which voltages and currents are constant (not changing with time), the currents are limited by resistance.

Circuits are important in guiding energy within devices and also to-and- from devices that are combined into systems. Electrical devices perform such functions as generation amplification, modulation and detection.

Systems incorporate circuits and devices to accomplish desired end results, such as generating a high voltage arc to produce O₃ through ionization. Sheet Metal Duct:

The purpose of outlets on the aspirator's sectional parts is to control air motion so 0₃ can be produced in each section. Ductwork air velocity of the duct are sized on the basis of air quantity, within the limitations of allowable friction losses, velocity and noise. In design methods the equal-friction method is applicable primarily to systems using low or moderate velocities where the velocity head is not an important factor.

The static-regain method is used for both conventional and high- velocity systems. It is especially applicable in the latter, where the velocity head may be appreciable. In the static-regain method, the static pressure required to give proper airflow through the systems outlets is determined, and this pressure is maintained by reducing the velocity at each branch or takeoff.

Variable Speed Fan:

In a variable speed fan the motor is fundamentally a variable speed motor, the speed varying widely from light load to full load and more. The variable speed fan is controlled through a digital system which controls the speed by the static input of the Flow Through Nozzle.

In Figure 29, we take a closer look at the O₃ aspirator where (117) illustrates a layer of insulation place against the wall of the stainless steel pipe. (118) illustrates a ceramic lining on top of the insulation and (119) illustrates a capped end with a hole for the stainless steel tube to protrude through. (120) illustrates the other end capped or blanked off and (121 ) illustrates a metal plate welded on the sectional stainless steel plate walls. (122) illustrates a hole where a circular duct or pipe will be installed to supply air to each separate section, (123) illustrates special raised bolts to accept the circuit board. (124) is a spacer and vibration absorber for the board and (125) is a washer placed on both sides of board. (126) is the bolts to secure the board in place and (127) is the actual circuit board used in producing ozone(O₃). (128) illustrates capacitor (129) illustrates resistors, (130) illustrates transistors, (131 ) illustrates pulse timer, (132) illustrates diode array, (133) illustrates a coil, (134) illustrates a high voltage probe and (135) illustrates a protective case that the probe would be surrounded by for safety reasons.

In Option II, the most important added feature is the ability to produce O₃(ozone) within the O₃ aspirator. To fully appreciate and understand ozone generations we must look back at ionization. What does "air ionization" mean? All matter is made up of tiny components known as atoms. Atoms, in turn, are made of still smaller units electrons, protons, and neutrons. Each electron has a small negative electrical charge, and each proton has as similar small positive electrical charge, and Neutrons are electrically neutral. An atom's protons and neutrons are bunched together into a cluster known as the "nucleus". The electrons orbit around the nucleus, somewhat like planets around the sun.

Ordinarily, the electrical charge of an atom is neutral; that is, the negative charges (from electrons) within the atom exactly equal and cancel out the positive charges (from protons). This means that each ordinary atom has exactly as many electrons as it has protons. But under many conditions, an atom may lose one (or possibly more) of its orbiting electrons. This means that the atom now has more protons than electrons, so the total internal positive charges outweigh the total internal negative charges. The atom as a whole has a small positive electrical charge. Such an atom is called a "positive ion". Positive ions and negative ions frequently occur randomly to the molecules of the air because of the loose atmospheric atoms are constantly moving about and often bump into one another disturbing the orbit of some of the electrons.

Oxygen is an element that is easily ionized. So, when I refer to ions, I am referring specifically to oxygen ions. Because ions are by definition an electrical phenomenon, its only natural for electronics be involved. Special high-voltage circuits have been designed to emit either negative ions or positive ions. The name of such a device is an ion generator. All such devices work in similar way.

A high voltage is built-up and then discharged by some form of probe. When the voltage is discharged it emits a strong burst of ions that attach themselves to atoms moving pass the probe, thus, creating many positive or negative ions. In effect, an ion generator acts like a small self-contained and controllable source of lighting bolts. Figure 30, illustrates the circuitry for the O₃ aspirator ion-generator.

136 illustrates a part list suitable for the O₃ generator, and the circuit is basically a high-voltage pulse generator where the system is known as the high-voltage corona discharge method. The ICI(137) is a 555(or 7555) timer chip operated in the astable mode. Using the component values in the parts- list(136) the pulse frequency is approx. 65HZ, with a duty cycle of a little less than 10% or it can be described as a string of very narrow pulses. Transistors Q1 (138) and Q2(139) are a Darlington-pair amplifier for the pulses and both transistors or nPn. The output from the amplifier stage is T1 (140) which is actually a standard 12-V, 3 -terminal ignition coil. The coil assembly boosts the potential of the pulses considerably. The signal is half wave rectified by D1 (141 ) which is a 45-KV (45,000 volt) high-voltage diode assembly. Filter capacitors C5(142), C6(143), and C7(144) are high-voltage units and a total series capacitance of 140 UF.

The capacitors working together act like a standard filter capacitor in a half-wave power rectification circuit. Once filtered the high-voltage output pulses from the generator circuit are fed to the probe(145). Explanation of the individual components are explained below.

Resistors

The two main characteristics of a resistor are its resistance R in ohms and its power rating in watts W. Resistors are available in a very wide range of R values, from a fraction of an ohm to many megaohms. The power rating may be as high as several hundred watts or as low as 1/10 watt.

The R is the resistance value required to provide the desired I or IR voltage drop. Also important is the wattage rating because it specifies the maximum power the resistor can dissipate without excessive heat. Dissipation mean the power is wasted l²R loss, since the resultant heat is not used. There are many different types of resistors but two types are used more often than other and they are:

(a) Wire-Wound Resister: in this construction, a special type of wire called resistance wire is wrapped around an insulating core. The length of wire used and its specific resistively determine the R of the unit. Types of resistance wire include tungsten and manganin. The insulated core is commonly porcelain.

(b) Carbon-Composition Resistors: This type of resistor is made of finely divided carbon or graphite mixed with a powdered insulating material as a binder, in the proportions needed for the desired R value. Figure 31 , illustrates a typical resistor where (146) illustrates an insulating core, (147) illustrates resistance wire wrapped around the core, (148) illustrates tinned leads, (149) illustrates epoxy coating, and (150) illustrates the colour coded bands to determine the size of the resistor.

Capacitors

Commercial capacitors are generally classified according to the dielectric. Most common capacitors are air, mica, paper, and ceramic, plus the electrolytic type.

Electrolytic capacitors use a molecular-thin oxide film as the dielectric, resulting in large capacitance values in little space. There is no required polarity, since either side can be the positive plate, except for electrolytic capacitors. These are marred to indicate which side must be positive to maintain the internal electrolytic action that produces the dielectric required to form the capacitance.

Figure 32, illustrates the aluminium foil type capacitor, the negative aluminium electrode(151 ) and the positive aluminium electrode(152) are in an electrolyte(153) of borax, phosphate, or carbonate. Between the two aluminium strips, absorbent gauze(154) soak-up electrolyte to provide the required electrolysis that produces an oxide film(155). This type is considered a wet electrolytic, but can be mounted in position.

Diodes

The standard symbol for a semiconductor diode is an arrow showing the direction of a hole flow and a bar as shown in Figure 33A. The anode(156) or arrow side of the symbol contains the P-type material(157), whereas the cathode or bar(158) side has the N-type semiconductor^ 59). In terms of free electrons, we can think of the diode as a one-way valve that will permit electron flow against the arrow in the symbol.

In Figure 33B the semiconductor diode illustrates the cathode end(160) marked with + to show that this terminal is for positive dc output voltage in an rectifier circuit and an arrow marked on the anode(161) side to illustrate direction. This type of diode is a "top hat" style package.

The only numbering system is the letter N for semiconductors and the prefix 1 for diodes with one junction. The 1 indicates only one junction, compared with two or more functions for transistors and thysistors. An example, IN4003 is a popular silicon diode. The IN prefix specifies that it is a semiconductor diode, while the 4003 part specifies the exact characteristics of the diode. In schematic diagrams, semiconductor diodes are commonly labelled D, CR, or X an Y. The CR stands for crystal rectifier.

Semiconductor diodes are sometimes specified as to their use. For instance, the silicon diode might be referred to as a rectifier because it is typically used to convert AC power input to DC output.

The two most important electrical specifications for a rectifier or power diode are PIV and l_F. The PIV specification stands for peak inverse voltage. This value is the maximum voltage the diode can tolerate in the reverse action. The l_F specification stands for forward current. The l_F is the maximum forward current through the diode when it is conducting. The Transistor (Bipolar)

This name means NPN and PNP transistors, as they have two opposite polarities of doped semiconductors. In Figure 34, the bipolar transistor consist of PN junction(162) and an NP junction(163), by making either a P or N semiconductor between opposite types. The purpose is to have the first section supply charges, either holes or electrons, to be collected by the third section, through the middle section. The electrode that supplies charges is the emitter(164); the electrode at the opposite end to collect the charges is the collector(165). The base(166) in the middle forms two junctions between emitter and collector. The direction is indicated by the emitter arrow(167).

(a) Emitter: the emitter - base junction is biased with forward voltage where typical values are 0.2V for Ge or 0.6V for Si. For the PNP transistor, the P emitter supplies hole charges to its junction with the base. The direction is indicated by the emitter arrow for forward hole current in the schematic symbol.

The arrow pointed into the base illustrates a PN junction between emitter and base, corresponding to the symbol for a PN diode. For the NPN transistor, the emitter supplies electrons to the base. Therefore, the symbol for the N emitter illustrates the arrow out from the base, opposite to the direction of electron flow.

(b) Collector: Its function is to remove charges from the junctions with the base. The PNP transistor has a P collector receiving hole charges and for the NPN transistor, the N collector receives electrons. The collector-base junction always has reverse voltage. Typical values are 4 to 100V. This polarity means that no majority charges can flow from collector to base. However, in the opposite direction, from base to collector the collector voltage attracts the charges in the base supplied by the emitter.

(c) Base: The base in the middle separates the emitter and collector. The base-emitter junction is forward-biased. As a result, the resistance for the emitter circuit is very low. The base-collector junction is reversed-biased, providing a high resistance in the collector circuit.

O₃ Aspirator Applications

Boilers In General:

Two general classifications may be applied to boilers; first with relation to the position of the water and hot gases as in "fire tube" or "water tube" boilers, second, with regard to the arrangement of the furnace and flues as in horizontal, vertical, and tubular. A fire tube boiler is one in which the hot gases flow inside tubes surrounded by water. This is the most common type of boiler found in large applications such as Central Heating Plants. The ends of the tubes are connected to headers and, by arrangement of these headers and the baffles which direct the flow of hot gases, the gases are caused to wipe the inside of the tubes back and forth, to assure maximum transfer of heat to the water.

The locomotive type of fire tube boiler looks like the railroad locomotive. In fact, this type of boiler was used on wheels, with power transmission equipment, cab, and controls attached. This design is used for stationary purposes, applied more to converting water to steam for power.

A common type of boiler design is the returns tubular. The gases travel from the furnace in the front, under the shell containing the water, towards the rear, then through the tubes to the front, into the breaching, and up the chimney or other.

Another form of return tubular boiler design is that type where the gases flow from the front through the lower half of the shell containing the tubes. Then by baffles, the gases are directed back through the tubes in the upper half of the shell to the front, into the breaching and out the chimney or other. The Scotch marine type of boiler design derived its popularity in early marine application. The need was for a lightweight, high-pressure boiler which was easy to service and would operate under full load for long periods of time with a minimum of attention. This boiler is also used in stationary applications where space limitations required this type of boiler. It is a fire tube boiler and in principle resembles the reverse tube boiler. The main difference is that the diameter and the length give it a short squashed appearance. The fire tubes are of larger diameter and there are usually two or three separate furnaces serving separate sets of tubes which all open into one common breaching.

There are hundreds of different types of boilers but they all have two things in common:

(1 ) They need a source of fuel to produce the energy fuels, such as coal, oil or natural gas;

(2) They all produce a flue gas which needs to be treated or controlled before entering the atmosphere.

The O₃ Aspirator can be applied to any type of boiler to convert noxious pollutants such as NO to NO₂ or SO to SO₂ where it can easily be capture down stream of the Aspirator by water or some other media. Figure 35 illustrates a typical installation of an O₃ Aspirator on a boiler system. (168) illustrates a typical boiler that could be oil fired, gas fired or a combination of oil and gas fired. (169) illustrates a boiler breaching exiting the back end of boiler. (170) illustrates, an O₃ Aspirator installed in the breaching as part of the breaching circuit. (171) illustrates an ozone generator supplied by other manufacture. The ozone generator supplies O₃ to the Aspirator for even distribution and mixing. (172) illustrates a typical wet scrubber which would be supplied by a scrubber manufacture. Note that a Comply 2000 unit can be installed in place of the wet scrubber to perform the removal of No_x or So_x with the added feature of heat recovery. The Comply 2000 is manufactured by EEP (Enviro-Energy Products).

A pollution control device such as the wet scrubber or Comply 2000 needs to be used with the O₃ Aspirator, the Aspirator will chemically change a non-soluble pollutant into a soluble pollutant, however, it does not remove the converted pollutant on its own and needs the assistance of a product such as mentioned above.

Figure 36 illustrates another typical boiler to O₃ Aspirator application with the exception that the O₃ Aspirator generates its own ozone and shows multiple boiler system. (173) illustrates multiple boilers using either oil, natural gas or combination of both. (174) illustrates multiple breaching tied into one common breech. (175) illustrates O₃ Aspirator with self-generations of ozone and (176) illustrates a Comply 2000 unit which captures and eliminates the converted pollutants.

Gas Turbines in General:

In its simplest form the gas turbine is small, light and requires only a modest foundation and building, does not require cooling water, runs unattended and can be remotely or automatically controlled. It is capable of rapid start-up and loading, low standby losses, low maintenance. Gas turbines can be arranged to supply power, high pressure air, or hot exhaust gases singly or combination.

Over two-thirds of the large industrial gas turbines are in electric- generating use.

Electric utility companies in the United States use gas turbines for peak-load duty. Gas turbines are used for base-load electric generation where additional capacity is needed quickly, where refined fuel, such as natural gas, is available at low cost, or where turbine exhaust energy can be utilized.

With the operation of a gas turbine the exhaust needs to be treated because of high concentration of No_x. The O₃ Aspirator can be installed on the exhaust of a gas turbine with certain parameters or guidelines met. Illustrated as a block diagram Figure 37 demonstrates a typical heat recovery cycle for 160w (200 KVA) gas turbine with the addition of an O₃ Aspirator and Comply 2000 unit.

(177) illustrates air intake at 70°F temperature, (178) illustrates the compressor used in the turbine. (179) illustrates the combustor of the turbine and (180) illustrates the actual turbine. (181 ) illustrates a 200KVA generator and (182) illustrates the exhaust pipe with a 1100°F temperature.

(183) demonstrates an exhaust gas by pass valve for safety reasons and

(184) illustrates a waste heat boiler that converts hot flue gas into low pressure steam. (185) illustrates the exhaust pipe after the waste heat boiler where the temperature is now 300°F and (186) illustrates the O₃ Aspirator with self-generation of ozone to convert the NO to NO₂. (187) illustrates a Comply 2000 where one of its functions is to remove the converted pollutant. (188) illustrates a 2880 pound per hour of steam at 15 PSIG that was produced by the waste heat boiler. (189) illustrates the 2880 pounds per hour of steam at 15 PSIG can be sent on and used for heating or process. (190) demonstrates a 430 pounds per hour excess steam that could be used for domestic hot water heating. (191 ) illustrates a 15 PSIG steam supplied to a generator condenser of an absorption chiller and (192) illustrates a make-up

feed water line at 250°F temperature coming from the absorption chiller. (193) illustrates a feed pump to direct the 250°F water to the waste heat boiler. (194) illustrates an absorption water chiller and (195) demonstrates a 125 ton absorber and (196) illustrates the generator condenser of the chiller. (197) demonstrates a chilled water line leaving the chiller at 45°F temperature and (198) illustrates the chilled water coming back to the chiller at 55°F temperature. (199) illustrates a city water line going to the Comply 2000 unit at 60°F and (200) illustrates after water has pass through both coils and sent on to be used for heat or process with a temperature of 180°F plus.

On-site generation provides an opportunity for utilization of the fuel energy not converted by the prime mover into shaft horsepower. If the heat cannot be used effectively the plant efficiency is only the prime mover thermal efficiency.

However, if project heat energy requirements can effectively use the normally wasted heat at the level it is available from the prime mover and controlled the pollutants far below required regulation, such salvaged heat will reduce the normal fuel requirements and reduce the pollution of the project, will increase the total overall plant efficiency proportionately.

Similar to a gas turbine there is cogeneration where a reciprocating internal combustion engines using diesel fuel or natural gas can produce electricity for a plant. Figure 38, illustrates a block diagram of a heat recovery cycle of a hot water engine cooling with steam heat recovery of the exhaust where (201) illustrates a reciprocating internal engine with (202) fuel injection control panel. (203) illustrates a water jacket circulating pump and (204) represents the water jacket supply coming from the engine and out to auxiliary heating equipment. (205) illustrates the water jacket return coming from auxiliary heating equipment. (206) illustrates engine exhaust gases at approximatelyl 100°F temperature and (207) demonstrates a hot flue gas bypass for safety. (208) illustrates a waste heat boiler producing steam from the waste heat flue gas. (209) illustrates a 300°F temperature after leaving the waste heat boiler and (210) illustrates a O₃ Aspirator with self generation of ozone that mixes with the flue gas to convert NO to NO₂ and SO to SO₂. (211 ) demonstrates a Comply 2000 unit that captures the pollutants and removes them via waste water. (212) illustrates a 5 PSIG steam header with branches running out to supply heating or processes. (213) illustrates a city cold water line that enters into the waste heat boiler to be made into steam.

(214) illustrates a make-up cold water line entering the Comply 2000 and

(215) illustrates a hot water line sent to auxiliary heating equipment. (215) is the end result of heat recovered from the flue gas.

In conclusion, the O₃ Aspirator will adapt to any type of flue gas stream where through a combustion process using fossil fuels such as coal, oil and natural gas produces a dirty flue gas stream.

Other devices such as gas fired chillers, after burners, incineration for paint booths and industrial gas fired HVAC units can also be adapted with an O₃ Aspirator.

Claims

1. Apparatus for oxidizing NO to NO₂ in a gas stream using ozone gas comprising piping for the gas stream, tubing for the ozone gas, and pitot tubes; the piping for the gas stream including at least one hole defining an opening in the gas stream piping, an ozone carrying tube extending from outside the gas stream pipe through the opening into the interior of the gas stream pipe, an axially disposed pitot tube extending in the direction of flow of the gas stream connected to the end of the ozone carrying tube, said pitot tube adapted to aspirate ozone into the gas stream.

2. The apparatus for oxidizing NO to NO₂ of claim 1 in which the gas stream pipe is comprised of a gas stream inlet pipe, a reducer pipe, a gas stream median pipe, an expander pipe and a gas stream outlet pipe, in which the diameter of the gas stream median pipe is less than the diameter of the gas stream inlet and gas stream outlet pipe, in which the axially disposed pitot tube is adapted to aspirate ozone into the gas stream immediately upstream of the reducer pipe.

3. Apparatus for oxidizing NO to NO₂ in a gas stream using ozone gas comprising piping for the gas stream, tubing for ozone gas, and pitot tubes, the piping for the gas stream including a series of holes defining equally spaced openings about a selected circumference of the gas stream pipe, a series of ozone carrying tubes extending from the outside of the gas stream pipe through respective equally spaced openings into the gas stream pipe, a series of axially disposed pitot tubes in the gas stream pipe attached to respective interior endings of ozone carrying tubes, said series of axially disposed pitot tubes extending axially in the direction of flow of the gas stream within the gas stream pipe in which the axially disposed pitot tubes are adapted to aspirate ozone into the gas stream.

4. The apparatus for oxidizing NO to NO₂ of claim 3 in which the gas stream pipe is comprised of a gas stream inlet pipe, a reducer pipe, a gas stream median pipe, an expander pipe and a gas stream outlet pipe, in which the diameter of the gas stream median pipe is less than the diameter of the gas stream inlet and gas stream outlet pipe, in which the ozone is adapted to be aspirated from the pitot tubes in proximity to the reducer pipe.

5. The apparatus for oxidizing NO to NO of claims 1 and 3 in combination with an ozone generator in which the exterior of the gas stream inlet pipe serves as the base for at least one enclosure of an ozone generator in which ozone is generated by converting O to O₃.

6. A method for oxidizing NO to NO₂ in a gas stream pipe using ozone, comprising flowing a gas stream having NO as an ingredient in one direction through a pipe, aspirating ozone into the gas stream in the direction of flow of the gas stream to oxidize the NO in the exhaust gas to NO₂.

7. A method for oxidizing NO to NO₂ in a gas stream in a pipe using ozone of claim 6 in which the flow of the gas stream is restricted immediately downstream of the aspiration of ozone.

8. The method for oxidizing NO to NO₂ in a gas stream in a pipe using ozone of claim 6 including means in said gas stream pipe just downstream of the ozone aspiration to cause uniform mixing of the gas stream and ozone in the gas stream pipe in the ozone aspiration area of the gas stream pipe.

9. Apparatus for generation of ozone comprising an enclosure, an air supply, a variable speed fan, variable speed fan controls, a high voltage pulse generator, a high voltage pulse generator control, a probe, an ozone expelling tube and piping, a number of holes defining openings in the enclosure for an air supply, a probe, and a tube for expelling ozone from the enclosure, a variable speed fan for supplying air to the enclosure in response to the variable speed fan control, a probe suspended within the enclosure, a high voltage pulse generator connected to the probe, a high voltage pulse generator control controlling the high voltage pulse generator, and tubing attached to the ozone expelling opening for transporting ozone.

10. A method for generation of ozone in an enclosure having holes defining openings for receiving a forced controlled air supply, a high- voltage pulse generating probe, and removal of ozone comprising forcing a controlled amount of air into the enclosure, generating a series of high voltage output pulses at the probe, ionizing the oxygen in the controlled forced air to ozone, and removing the ozone from the enclosure.

11. A low current high voltage circuit for generating ozone in an enclosure utilizing a series of high voltage positive ion output pulses at a probe.

12. The low current high voltage circuit for generating ozone in an enclosure utilizing a series of high voltage positive ion output pulses of claim 11 in which the current is less than 1 amp.

13. The low current high voltage circuit for generating ozone in an enclosure utilizing a series of high voltage positive ion output pulses of claim 11 in which the current is 2 amps or less.

14. The low current high voltage circuit for generating ozone in an enclosure utilizing a series of high voltage positive ion output pulses of claim 11 in which the high voltage is 35 KV to 150 KV.

15. The low current high voltage circuit for generating ozone in an enclosure utilizing a series of high voltage positive ion output pulses of claim 11 in which the high voltage is 45 KV to 100 KV.

16. A low current high voltage circuit for generating ozone in an enclosure utilizing a series of high voltage positive ion output pulses at a probe comprising a power supply, switch, resistors, capacitors, timer, transistors, coil, and half wave rectifier in the reverse position, a series of capacitors and a probe in which the power supply operates on a load of 1 amp or less.

17. A low current high voltage circuit for generating ozone in an enclosure utilizing a series of high voltage positive ion output pulses at a probe comprising a power supply, switch, resistors, capacitors, timer, transistors, coil, and halfway rectifier in the reverse position, a series of capacitors and a probe in which the output is 35 KV to l50 KV.