CN100531867C - Method and device for combined removal of sulfur dioxide and nitrogen oxides by mixed solution - Google Patents

Abstract

The invention is concerned with a method to remove sulfur dioxide and compounds of nitrogen and oxygen by using a kind of mixed solution. Drop the temperature of gas after moving dust to 100 to 110 degree, and contact with carbamide / ammonia mixed solution with additive to absorb sulfur dioxide and compounds of nitrogen and oxygen, then blow compressed air into the solution to get ammonia sulfate. Remove the solution and make gas contact with carbamide solution with additive, then let out after reaction. It can adopt double level spray or column reactor to coupling the first and second reactors into a same container and separate double lever reactor with clapboard, this predigests the connecting structure of double lever reactor and reduce the height of cleaning equipment and heat lost.

Description

Method and device for combined removal of sulfur dioxide and nitrogen oxides by mixed solution

technical field

The invention belongs to the technical field of atmospheric environmental protection, and relates to a method and a desulfurization and denitrification device for simultaneous flue gas desulfurization and denitrification, in particular to a method and device for jointly removing sulfur dioxide and nitrogen oxides by using a urea/ammonia water/additive mixed solution.

technical background

Sulfur dioxide and nitrogen oxides are the most influential gaseous pollutants in the air pollutants, which _are extremely harmful to the human body, the environment and _the ecological system. focus on. Sulfur dioxide and nitrogen oxides are mainly derived from the combustion process of coal, petroleum and other petrochemical fuels, as well as the flue gas emissions from the roasting and smelting of ores. It is difficult to manage due to its characteristics of large size and large amount of floating dust. In the traditional technology, the purification technology of sulfur dioxide and nitrogen oxides in exhaust flue gas usually separates desulfurization and denitrification, which causes the defects of complex and large exhaust gas purification system, large initial investment, and high operating cost, which seriously restricts the emission of flue gas. The actual implementation of gas desulfurization and denitrification. Flue gas desulfurization technologies mainly include limestone-gypsum wet method, rotary spray semi-dry method, calcium spray tail humidification and activation in the furnace, seawater desulfurization, electron beam desulfurization, flue gas circulating fluidized bed desulfurization, etc., among which wet limestone method is The most widely used flue gas desulfurization technology in the world today, its main problems are the low solubility of absorbent (lime or limestone), low utilization rate, and large amount of waste residue; flue gas denitrification technology mainly includes selective catalytic reduction technology (SCR) , Selective non-catalytic reduction technology (SNCR), electron beam method, pulse corona method, complex absorption method and urea absorption method, etc. The relatively mature flue gas denitrification technologies currently in operation are mainly SCR technology, SNCR technology and SNCR technology. /SCR combination technology, but the SCR method has the disadvantages of high initial investment cost, narrow operating temperature range, ammonia leakage, N ₂ O generation, and easy deactivation of the catalyst; while SNCR denitrification efficiency is low and ammonia leakage is large. , causing secondary pollution. In recent years, all countries in the world, especially industrially developed countries, have successively carried out the research and development of simultaneous desulfurization and denitrification technology, and have carried out certain industrial applications. At present, there are electron beam irradiation method, pulse corona method, activated carbon adsorption method, NOxSO process and Pahlman flue gas desulfurization and denitrification technology, etc., but my country still lacks such technology or is not suitable due to high energy consumption and cost. The Chinese invention patent (application number: 91105599.1) proposes desulfurization and denitrification at different high temperature sections in the furnace with ammonia water, ammonium sulfate or its acidic aqueous solution, urea and its compound powder or its aqueous solution. This invention has some similarities with the present invention in the desulfurization and denitrification agent, but its use process is completely different from this method, especially the use temperature section is different, and its effect is also very different. The Chinese invention patent (application number: 91105599.1) is used in the high-temperature section of the furnace, which will inevitably bring about high energy loss and corrosion in the furnace. Therefore, the search for a flue gas purification technology with high efficiency, low cost, low operating cost and no secondary pollution has become a concern of environmental protection researchers in my country.

Contents of the invention

The invention aims to provide a method and device for combined removal of sulfur dioxide and nitrogen oxides by mixed solutions in the low temperature section with high overall efficiency, low investment cost, low operating cost and no secondary pollution.

The present invention adopts following technical scheme:

Mixed solution of the present invention joint removal sulfur dioxide and nitrogen oxide method are as follows

Step 1: Cool the flue gas after dedusting to 100°C to 110°C, then make the flue gas contact with the urea/ammonia water mixed solution mixed with additives, and the liquid-gas ratio of the mixed solution to the flue gas is 1.5 ～4L/m ³ , the concentration of ammonia water in the mixed solution is 2%～10%, the concentration of urea in the mixed solution is 2%～6%, the mixed solution is used as the primary absorption solution and its pH value is maintained at 5～ 7. The temperature is controlled at 30°C to 60°C. _SO2 and NO in the flue gas are absorbed, and compressed air is blown into the solution after contacting with the flue gas and reacting to oxidize ammonium sulfite to ammonium sulfate. The above additives The addition amount is 0.005%～0.025% mass percentage content of urea/ammonia solution;

The second step: remove the solution entrained in the flue gas after the first-level absorption, and then make the flue gas contact with the urea solution mixed with additives, and discharge it after the reaction is completed. The above-mentioned urea solution and the flue gas after the first-level absorption The liquid-gas ratio is 5-20L/m ³ , the mass concentration of urea in the solution containing additives is 4%-13%, the solution containing additives is used as the secondary absorption solution and its pH value is maintained at 5.5-8, and the temperature is controlled At 30° C. to 60° C., the additive is added in an amount of 0.005% to 0.025% by mass of the urea solution.

The device of the present invention for implementing the mixed solution joint removal of sulfur dioxide and nitrogen oxides is composed of a heat exchanger, a primary gas distributor, a primary absorption reactor, a primary demister, and a secondary gas distributor. , secondary absorption reactor, secondary demister, secondary circulation pump, secondary liquid collection tank, pump, centrifuge, primary liquid collection tank, separation liquid pump, air compressor, and primary circulation pump. The primary gas distributor is set in the primary absorption reactor, the secondary gas distributor is set in the secondary absorption reactor, the flue gas outlet of the heat exchanger is connected with the flue gas inlet of the primary absorption reactor, and the primary absorption reactor The flue gas outlet is connected to the flue gas inlet of the secondary absorption reactor, and the primary demister is located between the flue gas outlet of the primary absorption reactor and the flue gas inlet of the secondary absorption reactor. The secondary demister is installed on the flue gas outlet of the secondary absorption reactor, the primary liquid collection tank is provided below the primary absorption reactor, and the primary circulation pump is provided between the circulating liquid outlet of the primary liquid collection tank and the first Between the liquid inlets of the first-stage absorption reactors and the inlet of the first-stage circulation pump is connected to the outlet of the circulating liquid of the first-stage sump, the outlet of the first-stage circulation pump is connected to the liquid inlet of the first-stage absorption reactor, and the second-stage circulation pump is connected to the liquid inlet of the first-stage absorption reactor. The liquid collecting tank is arranged under the secondary absorption reactor, and the secondary circulating pump is arranged between the circulating liquid outlet of the secondary liquid collecting tank and the liquid inlet of the secondary absorbing reactor, and the inlet of the secondary circulating pump is connected to the secondary absorbing reactor. The outlet of the circulating liquid in the first-stage collecting tank is connected, the outlet of the second-stage circulating pump is connected with the liquid inlet of the second-stage absorption reactor, the outlet of the ammonium sulfate crystallization solution of the first-stage collecting tank is connected with the inlet of the centrifuge, and the outlet of the centrifuge The liquid outlet is connected to the inlet of the separation liquid pump, the outlet of the separation liquid pump is connected to the inlet of the primary liquid collection tank, the outlet of the air compressor is connected to the inlet of the primary liquid collection tank, and the concentrated ammonium sulfite solution of the secondary liquid collection tank is The discharge port is connected with the inlet of the primary sump through a pump.

A kind of improvement plan of the device that is used for implementing mixed solution joint removal sulfur dioxide and nitrogen oxide method described in the present invention is to be made up of heat exchanger, integral type primary and secondary reactor, secondary mist eliminator, secondary circulating pump, Composed of pumps, centrifuges, separation liquid pumps, air compressors, and primary circulation pumps, the integral primary and secondary reactors include a cylinder, and a partition is arranged in the cylinder and a space surrounded by the partition and the cylinder It is the primary absorption reactor, and the other space surrounded by the partition and the cylinder is the secondary absorption reactor. The lower part of the first-level gas distributor is provided, the lower end of the first-level absorption reactor is connected with a first-level liquid collection tank, and the upper part of the first-level absorption reactor is equipped with a first-level demister. There is a first-stage sprayer under the demister, and the nozzle of the first-stage sprayer is downward, and the flue gas outlet of the second-stage absorption reactor is provided on the second-stage absorption reactor, which is connected to the lower end of the second-stage absorption reactor. There is a secondary liquid collection tank, a secondary gas distributor is provided on the upper part of the secondary absorption reactor, a secondary sprayer is provided in the secondary absorption reactor and below the secondary gas distributor, and the secondary spray The nozzle of the first-stage demister is downward, the first-stage mist eliminator and the second-stage gas distributor are connected by a channel, the flue gas outlet of the above-mentioned heat exchanger is connected with the flue gas inlet of the first-stage absorption reactor, and the second-stage mist eliminator is set On the flue gas outlet of the reactor, the primary circulating pump is installed between the circulating liquid outlet of the primary liquid collection tank and the liquid inlet of the primary sprayer, and the circulation between the inlet of the primary circulating pump and the primary liquid collection tank The outlet of the primary circulating pump is connected to the liquid inlet of the primary sprayer, and the secondary circulating pump is set between the circulating liquid discharge port of the secondary liquid collection tank and the liquid inlet of the secondary sprayer The inlet of the secondary circulation pump is connected to the outlet of the circulating liquid of the secondary liquid sump, the outlet of the secondary circulation pump is connected to the liquid inlet of the secondary sprayer, and the outlet of the secondary circulation pump is connected to the secondary absorption reactor. The liquid inlet is connected, the ammonium sulfate crystallization solution outlet of the first-level liquid collection tank is connected to the inlet of the centrifuge, the liquid outlet of the centrifuge is connected to the inlet of the separation liquid pump, and the outlet of the separation liquid pump is connected to the inlet of the first-level liquid collection tank Connection, the outlet of the air compressor is connected to the inlet of the first-level sump, and the outlet of the concentrated ammonium sulfite solution of the second-level sump is connected to the inlet of the first-level sump through a pump.

Another scheme of the device for implementing the mixed solution joint removal method for sulfur dioxide and nitrogen oxides in the present invention is composed of a heat exchanger, an integral primary and secondary reactor, a secondary demister, a secondary circulation pump, Composed of pumps, centrifuges, separation liquid pumps, air compressors, and primary circulation pumps, the integral primary and secondary reactors include a cylinder, and a partition is arranged in the cylinder and a space surrounded by the partition and the cylinder It is the primary absorption reactor, and the other space surrounded by the partition and the cylinder is the secondary absorption reactor. The lower part of the primary gas distributor is provided, the lower end of the primary absorption reactor is connected with a primary liquid collection tank, the upper part of the primary absorption reactor is provided with a primary demister, and the lower part of the primary absorption reactor is located at the primary A first-stage liquid column injector is arranged above the gas distributor, and the nozzle of the first-stage liquid column injector is upward, and a second-stage absorption reactor flue gas outlet is provided on the second-stage absorption reactor. The lower end is connected with a secondary liquid collection tank, a secondary gas distributor is provided on the upper part of the secondary absorption reactor, a secondary liquid column injector is provided on the lower part of the secondary absorption reactor, and a secondary liquid column injector The nozzle is upward, the primary demister and the secondary gas distributor are connected by a channel, the flue gas outlet of the above heat exchanger is connected to the flue gas inlet of the primary absorption reactor, and the secondary demister is installed in the secondary absorption reactor On the flue gas outlet, the primary circulation pump is set between the circulating liquid outlet of the primary liquid collection tank and the liquid inlet of the primary liquid column injector, and the circulation between the inlet of the primary circulation pump and the primary liquid collection tank The outlet of the first-stage circulating pump is connected to the liquid inlet of the first-stage liquid column injector, and the second-stage circulating pump is installed between the outlet of the circulating liquid of the second-stage liquid collection tank and the outlet of the second-stage liquid column injector. Between the liquid inlets and the inlet of the secondary circulating pump is connected to the circulating fluid outlet of the secondary liquid sump, the outlet of the secondary circulating pump is connected to the liquid inlet of the secondary liquid column ejector, and the outlet of the secondary circulating pump It is connected with the liquid inlet of the secondary absorption reactor (6), the outlet of the ammonium sulfate crystallization solution of the primary liquid collection tank is connected with the inlet of the centrifuge, the liquid outlet of the centrifuge is connected with the inlet of the separation liquid pump, and the separation liquid pump The outlet is connected to the inlet of the first-level sump, the outlet of the air compressor is connected to the inlet of the first-level sump, and the outlet of the concentrated ammonium sulfite solution of the second-level sump is connected to the inlet of the first-level sump through a pump. .

The working process of the present invention is as follows: the flue gas after dedusting enters the heat exchanger through the pipeline to cool down, and then enters the main body of the first-stage reactor through the pipe, and the flue gas in the main body of the first-stage reactor first passes through the first-stage gas distributor and enters the first-stage reactor evenly. The first-stage absorption reactor; the circulating absorption liquid in the first-stage liquid collection tank is pumped into the first-stage absorption reactor by the first-stage circulation pump through the pipeline; the ammonia solution in the ammonia water distribution tank is pumped into the air compressor by the ammonia water pump through the pipeline. The connected pipeline is sent into the first-level sump together with the compressed air, and the ammonium sulfate solution crystallized at the bottom of the first-level sump passes through the pipeline, and then is discharged into the centrifuge through the valve, and 98% of ammonium sulfate crystals are separated and centrifuged. The solution separated by the machine is pumped into the first-level liquid collection tank by the separation liquid pump through the pipeline; the flue gas after the first-level purification enters the main body of the second-level reactor through the first-level demister, and the flue gas first passes through the second-level gas distributor and then Enter the secondary absorption reactor; the circulating absorption liquid in the secondary liquid collection tank is pumped into the secondary absorption reactor by the secondary circulation pump through the pipeline; the urea solution in the urea solution dosing tank is sent into the secondary absorption reactor by the urea solution pump through the pipeline The pipeline connected with the secondary circulation pump is sent into the secondary absorption reactor together with the circulating liquid; when the circulating absorption liquid in the secondary liquid collection tank reaches a certain concentration of ammonium sulfate, it is pumped into the secondary absorption reactor through the pipeline by the pump and the air compressor The connected pipes are sent into the first-stage liquid collection tank together with the compressed air; the flue gas after the second-stage purification passes through the second-stage demister, enters the heat exchanger through the pipe to heat up, and then flows into the chimney through the pipe.

Compared with prior art, the present invention has following advantage:

The invention is a simultaneous desulfurization and denitrification process of wet urea/ammonia water/additive solution flue gas, using urea/ammonia aqueous solution as simultaneous desulfurization and denitrification agent, triethanolamine, ethylenediamine, etc. Gas-liquid mixing with the absorption liquid effectively realizes simultaneous desulfurization and denitrification process, and the absorption liquid is then oxidized to produce ammonium sulfate as a by-product. This process overcomes the shortcomings of the conventional flue gas purification process with single function. Low cost, low operating cost, no secondary pollution.

The basic process is as follows:

The polluted flue gas (about 160°C) containing sulfur dioxide and nitrogen oxides first enters the heat exchanger to cool down to 100°C to 110°C after dust removal, and then enters the main body of the primary reactor, and the flue gas enters the primary absorption reaction through the gas distributor urea/ammonia solution mixed with additives such as triethanolamine or ethylenediamine (the mass percentage of the additive is 0.005% to 0.025% of the urea/ammonia solution) (the concentration of the primary ammonia solution is 2% to 10% and urea The solution concentration is 2%-6%) for gas-liquid mixed contact, the pH value of the absorption solution is maintained at 5-7, the temperature is controlled at 30°C-60°C, and SO ₂ and NO _x in the flue gas are absorbed simultaneously; Compressed air is blown into the liquid collection tank of the main body of the primary reactor to oxidize ammonium sulfite into ammonium sulfate; the flue gas after the primary purification is removed by the demister to remove the entrained solution of the flue gas, and then enters the main body of the secondary reactor, and the flue gas Then enter the secondary absorption reactor through the gas distributor, again with the urea solution (the mass concentration of urea is 4～0.025% of the urea solution) mixed with additives such as triethanolamine or ethylenediamine (the mass percentage of the additive is 0.005%～0.025%) 13%) for gas-liquid mixed contact, the pH value of the absorption solution is maintained at 5.5-8, the temperature is controlled at 30°C-60°C, the SO2 _{and NOx} in the flue gas are removed again, and a small amount comes from the primary absorption reactor The ammonia is completely reacted here to meet the ammonia emission index; the flue gas after secondary purification is removed from the entrained liquid in the flue gas by a demister The temperature of the device is raised to 75 ° C ~ 90 ° C and discharged into the atmosphere. The total removal efficiency of _SO2 in the flue gas is 90%-99%, and the total removal efficiency of _NOx is 60%-85%. At the same time, the by-product ammonium sulfate is recovered, and no secondary pollutants are produced.

Using triethanolamine, ethylenediamine, etc. as additives, the principle of simultaneous desulfurization and denitrification of urea solution or urea and ammonia solution is as follows:

Reaction of Ammonia with _SO2 and _NOx :

SO ₂ +2NH ₃ +H ₂ O→(NH ₄ ) ₂ SO ₃ (1)

(NH ₄ ) ₂ SO ₃ +SO ₂ +H ₂ O→2NH ₄ HSO ₃ (2)

NH ₄ HSO ₃ +NH ₃ →(NH ₄ ) ₂ SO ₃ (3)

2(NH ₄ ) ₂ SO ₃ +O ₂ →2(NH ₄ ) ₂ SO ₄ (4)

4(NH ₄ ) ₂ SO ₃ +2NO ₂ →4(NH ₄ ) ₂ SO ₄ +N ₂ (5)

2(NH ₄ ) ₂ SO ₃ +2NO→2(NH ₄ ) ₂ SO ₄ +N ₂ (6)

2(NH ₄ )OH+NO+NO ₂ →2NH ₄ NO ₂ +H ₂ O (7)

2NH ₄ NO ₂ →2N ₂ +4H ₂ O (8)

Since the oxidation degree of nitrogen oxides in general flue gas is generally 5% to 10%, the denitrification efficiency of reaction formulas (5) and (6) is very small, and the existence of NH ₄ HSO ₃ is not conducive to (NH ₄ ) ₂ SO ₃ can absorb NO _x , and NH ₄ HSO ₃ can inhibit the reaction formula (7).

Reaction of urea with _SO2 and _NOx :

2NO+O ₂ →2NO ₂ (9)

Different components can be absorbed into the liquid phase, except for NO (the Henry constant of NO in water is very small, only 1.25*10 ^-3 mol/L at 50°C under normal pressure). The response is as follows:

It can be seen from reaction (16) that the decomposition of HNO ₂ will lead to the formation of NO, and urea will react with HNO ₂ to generate N ₂ and CO ₂ , which inhibits the occurrence of reaction (16). The response is as follows:

CO(NH ₂ ) ₂ +2HNO ₂ →2N ₂ +CO ₂ +3H ₂ O (17)

The reaction between absorbent urea and flue gas can be expressed by the following chemical reaction formula:

NO(g)+NO ₂ (g)+(NH ₂ ) ₂ CO(aq)=2H ₂ O(l)+CO ₂ (g)+2N ₂ (g) (18)

SO ₂ (g)+(NH ₂ ) ₂ CO(aq)+2H ₂ O(l)+0.5O ₂ (g)=(NH ₄ ) ₂ SO ₄ (aq)+CO ₂ (g) (19)

Using triethanolamine, ethylenediamine, etc. as additives, urea solution or urea and ammonia solution as absorbing/reducing agent, in the process of simultaneous desulfurization and denitrification of flue gas, not only urea and ammonia have their own corresponding desulfurization and denitrification effects, but also their The intermediate products also have a synergistic promotion effect, and at the same time, SO ₂ and NO _x in the flue gas also have a synergistic function, which greatly accelerates the chemical reaction rate during the reaction process and greatly improves the flue gas purification efficiency.

Additives such as triethanolamine and ethylenediamine mainly play a catalytic and buffering role in the reaction process. Catalysis refers to accelerating the reaction rate or inhibiting the occurrence of side reactions, and controlling the direction and process of the reaction; buffering refers to adjusting the pH value of the absorption liquid, making the absorption liquid tend to be weakly alkaline, and preventing corrosion of equipment.

Compared with traditional technology, the method of urea/ammonia/additive solution of the present invention combined removal of sulfur dioxide and nitrogen oxides in flue gas has the following specific advantages:

1. It has a wide range of applications. The process and equipment can be used for the removal of various tail gases and flue gases containing SO ₂ and NO _x , including domestic boilers, industrial boilers, industrial kilns, power plant boilers, metallurgical tail gas, and chemical tail gas; It can effectively remove both high and low concentrations of SO ₂ and NO _x flue gas.

2. Using the urea/ammonia/additive solution to simultaneously remove sulfur dioxide and nitrogen oxides in the flue gas, the flue gas in the primary reactor is mixed with the mixed solution of ammonia and urea, and the _SO in the flue gas reacts with ammonia water to generate The intermediate product (NH ₄ ) ₂ SO ₃ has a decomposition effect on NO _x (reactions (5) and (6)), the intermediate product (NH4) ₂ SO ₃ and urea jointly absorb and remove NO _x in flue gas, and urea It can also accelerate the process and rate of the reaction (8), not only improving the removal efficiency of the absorption solution for _SO2 in the flue gas, but also greatly strengthening and improving the removal ability of the absorption solution for _NOx in the flue gas. At the same time, during the simultaneous desulfurization and denitrification process of flue gas, SO ₂ and NO _x also have a synergistic promoting effect, which is beneficial to the purification of flue gas. The method has high comprehensive efficiency, the total removal efficiency of _SO2 is 90%-99%, and the total removal efficiency of _NOx is 60%-85%. Its comprehensive performance can be compared with the current popular combination of wet limestone desulfurization and SCR denitrification Comparable, while the by-product ammonium sulfate is recovered.

3. This urea/ammonia/additive solution combines the method of simultaneously removing sulfur dioxide and nitrogen oxides in the flue gas. The simultaneous desulfurization and denitrification of the flue gas is carried out in the low temperature section, which improves the overall heat utilization efficiency of the system and reduces energy consumption.

4. This method of urea/ammonia/additive solution combined removal of sulfur dioxide and nitrogen oxides in flue gas at the same time uses cheap triethanolamine, ethylenediamine and other additives, which not only reduces system operating costs, but also has catalytic and buffering effects. It accelerates the reaction rate of the absorption solution to _SO2 and _NOx , and makes the absorption solution tend to be weakly alkaline, preventing the corrosion of system equipment.

5. This method of urea/ammonia/additive solution combined with low temperature to simultaneously remove sulfur dioxide and nitrogen oxides in flue gas organically combines desulfurization and denitrification systems. The combination of desulfurization and SCR denitrification has been greatly simplified, saving initial investment costs and operating costs.

6. The method of simultaneously removing sulfur dioxide and nitrogen oxides in flue gas by using urea/ammonia/additive solution at low temperature, the product has high solubility in water, is not easy to scale, safe in operation, convenient in maintenance, and easy to control; The problem of fouling is avoided, and a suitable gas distributor can be used in the inlet section of the reactor, which greatly improves the uniformity of the flue gas in the reactor and improves the purification efficiency of the flue gas in the system.

7. This urea/ammonia/additive solution low-temperature combined method for simultaneously removing sulfur dioxide and nitrogen oxides in the flue gas adopts a two-stage reactor treatment process, in which the flue gas is mixed with ammonia and urea mixed solution in the first-stage reactor. Most of the SO ₂ and NO _x in the flue gas are removed by joint absorption, the flue gas passes through the primary demister to remove most of the liquid droplets in the flue gas, and a small amount of entrained ammonia enters the secondary reactor together with the flue gas; The flue gas in the first-stage reactor is only mixed with the urea solution, and the small amount of ammonia entrained by the flue gas from the first-stage reactor reacts with SO ₂ in the flue gas again, and the amino group is basically consumed, and the two-stage treatment process makes the reaction temperature It is easier to control and effectively solves the problems of aerosol and ammonia emissions caused by ammonia desulfurization.

8. This urea/ammonia/additive solution combines low temperature and simultaneous removal of sulfur dioxide and nitrogen oxides in flue gas. Due to the two-stage treatment process, different proportions can be used for high and low concentrations of _SO2 and _NOx flue gas The mixed solution of ammonia and urea is convenient for adjustment and control during operation, so that the simultaneous desulfurization and denitrification efficiency and operating cost of flue gas can achieve the best economic effect.

9. The combination of urea/ammonia/additive solution at low temperature and simultaneous removal of sulfur dioxide and nitrogen oxides in the flue gas achieves no secondary pollution emissions, which is conducive to environmental protection.

10. Using the integrated design technology of two-stage reactors, the primary and secondary reactors are coupled in the same container, and the two-stage reactors are separated by a partition, so that the outlet of the primary reactor and the secondary reactor The inlet becomes an internal channel, and the flow direction of the flue gas changes to the first upward and then downward flow mode, which not only greatly simplifies the connection structure of the two-stage reactor, reduces the height of the flue gas purification equipment, saves the initial investment cost, and reduces the equipment cost. space, and reduce the heat dissipation loss of the flue gas purification equipment, reduce the pressure of the subsequent temperature rise, and save energy; in addition, it also realizes the structural arrangement of the flue gas with low entry and low exit, which reduces the height of the subsequent flue gas pipeline and saves energy. It reduces the cost and facilitates the installation and maintenance of the equipment.

Description of drawings

Fig. 1 is the system flow diagram of urea/ammonia liquor/additive solution of the present invention combined and simultaneous removal of sulfur dioxide and nitrogen oxides in flue gas, wherein heat exchanger 1, primary gas distributor 2, primary absorption reactor 3, Primary demister 4, secondary gas distributor 5, secondary absorption reactor 6, secondary demister 7, urea solution pump 8, urea solution mixing tank 9, secondary circulation pump 10, secondary liquid collection Groove 11, pump 12, centrifuge 13, valve 14, primary liquid collection tank 15, separation liquid pump 16, air compressor 17, primary circulation pump 18, ammonia water pump 19, ammonia water distribution tank 20.

Fig. 2 is the structure diagram of the embodiment of primary and secondary spray absorption reactors of the present invention, wherein there are primary absorption reactor flue gas inlet 21, primary gas distributor 2, primary sprayer 22, primary purifier Mist 4, primary and secondary reactor partitions 23, secondary gas distributor 5, secondary sprayer 24, secondary demister 7, secondary absorption reactor flue gas outlet 25, reactor cylinder 28.

Fig. 3 is the structure diagram of the embodiment of the primary and secondary liquid column absorption reactors of the present invention, wherein there are primary absorption reactor flue gas inlet 21, primary gas distributor 2, primary liquid column ejector 26, primary Demister 4, primary and secondary reactor partitions 23, secondary gas distributor 5, secondary liquid column injector 27, secondary demister 7, secondary absorption reactor flue gas outlet 25, reactor Cylinder 28.

Detailed ways

Example 1:

Referring to Fig. 1, an embodiment of the method for the joint removal of sulfur dioxide and nitrogen oxides in flue gas by urea/ammonia/additive solution of the present invention will be described in detail.

The flue gas containing sulfur dioxide 600mg/Nm ³ ~ 6000mg/Nm ³ and nitrogen oxides 400mg/Nm ³ ~ 3000mg/Nm ³ is dedusted at about 160°C, enters the heat exchanger 1 through the pipeline and cools down to 100~110°C, and then enters a The main body of the first-stage reactor; the flue gas enters the first-stage absorption reactor 3 evenly through the first-stage gas distributor 2 and is mixed with additives such as triethanolamine or ethylenediamine. The urea/ammonia water mixed solution has a primary ammonia solution concentration of 2% to 10% and a urea solution concentration of 2% to 6% for gas-liquid mixed contact, where most of the _SO2 is absorbed and removed, and part of the _NOx is absorbed Remove; the primary absorption reactor 3 can be a spray tower, a packed tower or a liquid column tower; the pH value of the circulating absorbent solution in the main body of the primary reactor is maintained at 5 to 7, and the temperature is controlled at 30°C to 60°C. The ratio is 1.5-4L/m ³ , and the flue gas superficial velocity is controlled at 2.5-4m/s; the ammonia solution in the ammonia water distribution tank 20 is pumped into the primary liquid collection tank 15 by the ammonia water pump 19; the primary liquid collection tank The circulating absorption liquid in 15 is pumped into the primary absorption reactor 3 by the primary circulating pump 18 for recycling; the air compressor 17 blows compressed air into the primary liquid sump 15 to oxidize the ammonium sulfite produced by the reaction into Ammonium sulfate, the crystallized ammonium sulfate in the first-level sump 15 is deposited at the bottom, and after reaching a certain concentration, it is discharged into the centrifuge 13 through valves 14 and carried out solid-liquid separation to obtain 98% ammonium sulfate crystals, and the separated solution passes through The pump 16 is pumped into the first-level liquid collection tank 15; the flue gas after the first-level purification is removed by the first-level demister 4 to remove the entrained solution in the flue gas (to prevent ammonia from being brought into the main body of the second-level absorption reactor) from the first-level The flue gas of the main body of the primary reactor is passed through the secondary gas distributor 5 so that the flue gas enters the secondary absorption reactor 6 evenly, and is again mixed with additives such as triethanolamine or ethylenediamine (the additive mass percentage is 0.005% of the urea solution) %～0.025%) urea solution (urea mass concentration is 4～13%) for gas-liquid mixed contact, SO2 _{and NOx} in the flue gas are absorbed and removed again, and the flue gas entrained from the main body of the primary reactor A small amount of ammonia is also fully utilized here, which fully meets the discharge index of ammonia; the secondary absorption reactor 6 can be a spray tower, a packed tower or a liquid column tower; at this time, the pH value of the circulating absorbent solution is maintained at 5.5-8, The temperature is controlled at 30°C-60°C, the liquid-gas ratio is 5-20L/m ³ , the flue gas superficial velocity is controlled at 2.5-4m/s; into the secondary absorption reactor 6 for recycling; the urea solution in the urea solution distribution tank 9 is pumped into the secondary absorption reactor 6 by the urea solution pump 8; the circulating absorption liquid in the secondary liquid collection tank 11 reaches a certain When the concentration of ammonium sulfate is low, the pump 12 is pumped into the first-level liquid collection tank 15; the second-level purified flue gas is then passed through the second-level demister 7 to remove the entrained liquid in the flue gas (the temperature of the flue gas is 55 ° C ~ 70 ℃) after heat exchanger 1 Heat up to 75°C ~ 90°C and discharge into the chimney. After two-stage absorption and removal, the total removal efficiency of _SO2 is 90%-99%, and the total removal efficiency of _NOx is 60%-85%. At the same time, the by-product ammonium sulfate is recovered, and the whole system realizes recycling without secondary pollution. thing produced.

Embodiment 2: The method for combined removal of sulfur dioxide and nitrogen oxides by the mixed solution disclosed by the present invention is as follows:

Step 1: Cool the flue gas after dedusting to 100°C to 110°C, then make the flue gas contact with the urea/ammonia water mixed solution mixed with additives, and the liquid-gas ratio of the mixed solution to the flue gas is 1.5 ～4L/m ³ , the concentration of ammonia water in the mixed solution is 2%～10%, the concentration of urea in the mixed solution is 2%～6%, the mixed solution is used as the primary absorption solution and its pH value is maintained at 5～ 7. The temperature is controlled at 30°C to 60°C. _SO2 and _NOx in the flue gas are absorbed, and compressed air is blown into the solution after contacting with the flue gas and reacting to oxidize ammonium sulfite to ammonium sulfate. The above additives The addition amount is 0.005%～0.025% mass percentage content of urea/ammonia solution;

The second step: remove the solution entrained in the flue gas after the first-level absorption, and then make the flue gas contact with the urea solution mixed with additives, and discharge it after the reaction is completed. The above-mentioned urea solution and the flue gas after the first-level absorption The liquid-gas ratio is 5-20L/m ³ , the mass concentration of urea in the solution containing additives is 4%-13%, the solution containing additives is used as the secondary absorption solution and its pH value is maintained at 5.5-8, and the temperature is controlled At 30° C. to 60° C., the additive is added in an amount of 0.005% to 0.025% by mass of the urea solution.

In the method for combined removal of sulfur dioxide and nitrogen oxides by the above mixed solution, the additive is one or more than one of triethanolamine, ethylenediamine, and amine phosphate.

The flue gas after secondary absorption in the method of combined removal of sulfur dioxide and nitrogen oxide by the above mixed solution is discharged after the liquid entrained in the flue gas is removed by a demister.

Embodiment 3: A kind of device that is used to implement described mixed solution joint removal sulfur dioxide and nitrogen oxide method is to be made up of heat exchanger 1, primary gas distributor 2, primary absorption reactor 3, primary mist eliminator 4. Secondary gas distributor 5, Secondary absorption reactor 6, Secondary demister 7, Secondary circulation pump 10, Secondary liquid collection tank 11, Pump 12, Centrifuge 13, Primary liquid collection tank 15, Separation liquid pump 16, air compressor 17, primary circulation pump 18, primary gas distributor 2 is arranged in primary absorption reactor 3, secondary gas distributor 5 is arranged in secondary absorption reactor 6, heat The flue gas outlet of the exchanger 1 is connected to the flue gas inlet 21 of the primary absorption reactor, the flue gas outlet of the primary absorption reactor 3 is connected to the flue gas inlet of the secondary absorption reactor 6, and the primary mist eliminator 4 is located between the flue gas outlet of the primary absorption reactor 3 and the flue gas inlet of the secondary absorption reactor 6, the secondary demister 7 is set on the flue gas outlet 25 of the secondary absorption reactor, and the primary The sump 15 is arranged below the primary absorption reactor 3, and the primary circulating pump 18 is arranged between the outlet of the circulating liquid in the primary sump 15 and the liquid inlet of the primary absorption reactor 3, and the primary circulation The inlet of the pump 18 is connected to the outlet of the circulating liquid of the first-level liquid collection tank 15, the outlet of the first-level circulating pump 18 is connected to the liquid inlet of the first-level absorption reactor 3, and the second-level liquid collection tank 11 is located in the second-level absorption reaction. Below the device 6, the secondary circulation pump 10 is located between the outlet of the circulating liquid of the secondary liquid collection tank 11 and the liquid inlet of the secondary absorption reactor 6, and the inlet of the secondary circulation pump 10 is connected to the secondary liquid collection tank. 11 The circulating liquid outlet is connected, the outlet of the secondary circulation pump 10 is connected with the liquid inlet of the secondary absorption reactor 6, the outlet of the ammonium sulfate crystallization solution of the primary liquid collection tank 15 is connected with the inlet of the centrifuge 13, and the centrifuge The liquid outlet of 13 is connected with the inlet of separation liquid pump 16, the outlet of separation liquid pump 16 is connected with the inlet of primary liquid collection tank 15, the outlet of air compressor 17 is connected with the inlet of primary liquid collection tank 15, and the secondary liquid collection tank The concentrated ammonium sulfite solution outlet of the tank 11 is connected with the inlet of the first-level sump 15 by a pump 12 .

Described device is connected with ammonia water pump 19 and the inlet of primary liquid sump 15 is connected with the outlet of ammonia water pump 19 on the inlet of first-level sump 15, is connected with ammonia water liquid distribution tank 20 and ammonia water pump 19. The inlet of water pump 19 is connected with the outlet of ammonia water distribution tank 20.

The above-mentioned device is connected with a urea solution pump 8 on the inlet of the first-level sump 15 and the inlet of the first-level sump 15 is connected with the outlet of the urea solution pump 8, and the urea solution pump 8 is connected with a urea solution dispensing tank 9 and the inlet of the urea solution pump 8 is connected with the outlet of the urea solution distribution tank 9 .

Said device is provided with a valve 14 between the ammonium sulfate crystallization solution outlet of the first-stage sump 15 and the inlet of the centrifuge 13 .

The device is connected with the purified low-temperature flue gas inlet of the heat exchanger 1 at the flue gas outlet 25 of the secondary absorption reactor.

Example 4:

With reference to Fig. 2, a kind of device that is used to implement described mixed solution joint removal sulfur dioxide and nitrogen oxides method is to be made up of heat exchanger 1, monolithic primary and secondary reactor, secondary mist eliminator 7, secondary circulating pump 10. Composed of a pump 12, a centrifuge 13, a separation liquid pump 16, an air compressor 17, and a primary circulating pump 18, the integral primary and secondary reactor includes a cylinder 28, and a partition 23 is arranged in the cylinder 28 and consists of A space surrounded by the partition plate 23 and the cylinder body 28 is the primary absorption reactor 3, and another space surrounded by the partition plate 23 and the cylinder body 28 is the secondary absorption reactor 6. In the primary absorption reactor 3 is provided with a primary absorption reactor flue gas inlet 21, a primary gas distributor 2 is provided at the lower part of the primary absorption reactor 3, and a primary liquid collection tank 15 is connected to the lower end of the primary absorption reactor 3. The top of the absorption reactor 3 is provided with a primary demister 4, and in the primary absorption reactor 3 and below the primary demister 4 is provided with a primary sprayer 22, and the nozzle of the primary sprayer 22 is directed to Next, the secondary absorption reactor flue gas outlet 25 is provided on the secondary absorption reactor 6, the secondary liquid collection tank 11 is connected at the lower end of the secondary absorption reactor 6, and the upper part of the secondary absorption reactor 6 is provided with There is a secondary gas distributor 5, in the secondary absorption reactor 6 and below the secondary gas distributor 5 is provided with a secondary shower 24 and the nozzle of the secondary shower 24 is downward, and the primary demister 4 communicates with the secondary gas distributor 5 through channels, the flue gas outlet of the above-mentioned heat exchanger 1 is connected with the flue gas inlet 21 of the primary absorption reactor, and the secondary demister 7 is set at the flue gas outlet 25 of the secondary absorption reactor Above, the primary circulating pump 18 is located between the circulating liquid outlet of the primary liquid collection tank 15 and the liquid inlet of the primary sprayer 22 and the circulation between the inlet of the primary circulating pump 18 and the primary liquid collecting tank 15 The outlet of the primary circulating pump 18 is connected to the liquid inlet of the primary sprayer 22, and the secondary circulating pump 10 is connected to the circulating liquid discharge port of the secondary liquid sump 11 and the secondary sprayer 24. between the liquid inlets and the inlet of the secondary circulation pump 10 is connected to the circulating liquid outlet of the secondary liquid sump 11, the outlet of the secondary circulation pump 10 is connected to the liquid inlet of the secondary sprayer 24, and the secondary circulation The outlet of the pump 10 is connected with the liquid inlet of the secondary absorption reactor 6, the ammonium sulfate crystallization solution discharge port of the primary sump 15 is connected with the inlet of the centrifuge 13, and the liquid outlet of the centrifuge 13 is connected with the separator pump 16 Inlet connection, the outlet of the separation liquid pump 16 is connected to the inlet of the primary liquid collection tank 15, the outlet of the air compressor 17 is connected to the inlet of the primary liquid collection tank 15, and the concentrated ammonium sulfite solution discharge port of the secondary liquid collection tank 11 The pump 12 is connected to the inlet of the primary sump 15 . .

Example 5:

With reference to Fig. 3, a kind of device that is used for the combined removal of sulfur dioxide and nitrogen oxides method of described mixed solution is composed of heat exchanger 1, integrated primary and secondary reactor, secondary mist eliminator 7, secondary circulating pump 10. Composed of a pump 12, a centrifuge 13, a separation liquid pump 16, an air compressor 17, and a primary circulating pump 18, the integral primary and secondary reactor includes a cylinder 28, and a partition 23 is arranged in the cylinder 28 and consists of A space surrounded by the partition plate 23 and the cylinder body 28 is the primary absorption reactor 3, and another space surrounded by the partition plate 23 and the cylinder body 28 is the secondary absorption reactor 6. In the primary absorption reactor 3 is provided with a primary absorption reactor flue gas inlet 21, a primary gas distributor 2 is provided at the lower part of the primary absorption reactor 3, and a primary liquid collection tank 15 is connected to the lower end of the primary absorption reactor 3. The upper part of the absorption reactor 3 is provided with a first-level demister 4, and the lower part of the first-level absorption reactor 3 and above the first-level gas distributor 2 is provided with a first-level liquid column injector 26, and the first-level liquid column injector 26 The nozzle of the secondary absorption reactor is upward, and the secondary absorption reactor 6 is provided with a secondary absorption reactor flue gas outlet 25, and the lower end of the secondary absorption reactor 6 is connected with a secondary liquid collection tank 11, and at the bottom of the secondary absorption reactor 6 The upper part is provided with a secondary gas distributor 5, the bottom of the secondary absorption reactor 6 is provided with a secondary liquid column injector 27 and the nozzle of the secondary liquid column injector 27 is upward, and the primary demister 4 and the secondary The first-stage gas distributor 5 is connected by passages, the flue gas outlet of the above-mentioned heat exchanger 1 is connected with the flue gas inlet 21 of the first-stage absorption reactor, and the second-stage demister 7 is arranged on the flue gas outlet 25 of the second-stage absorption reactor. The first-stage circulating pump 18 is arranged between the outlet of the circulating liquid of the first-stage sump 15 and the liquid inlet of the first-stage liquid column injector 26, and the inlet of the first-stage circulating pump 18 is connected to the circulating liquid of the first-stage sump 15. The discharge port is connected, the outlet of the primary circulation pump 18 is connected to the liquid inlet of the primary liquid column ejector 26, and the secondary circulation pump 10 is set at the circulating liquid discharge port of the secondary liquid collection tank 11 and the secondary liquid column injector 26. Between the liquid inlets of the injectors 27 and the inlet of the secondary circulation pump 10 is connected with the circulating liquid outlet of the secondary liquid sump 11, the outlet of the secondary circulation pump 10 is connected with the liquid inlet of the secondary liquid column injector 27 Connect, the outlet of the secondary circulation pump 10 is connected with the liquid inlet of the secondary absorption reactor 6, the ammonium sulfate crystallization solution discharge port of the primary sump 15 is connected with the inlet of the centrifuge 13, and the liquid outlet of the centrifuge 13 It is connected to the inlet of the separation liquid pump 16, the outlet of the separation liquid pump 16 is connected to the inlet of the first-level liquid collection tank 15, the outlet of the air compressor 17 is connected to the inlet of the first-level liquid collection tank 15, and the concentrated sub- The ammonium sulfate solution discharge port is connected with the inlet of the first-level sump 15 by the pump 12.

Claims (9)

1, a kind of mixed solution is united and is removed sulfur dioxide and nitrogen oxide method, it is characterized in that:

The first step: with behind the flue gas cool-down to 100 after the dedusting ℃～110 ℃, make again flue gas with blending the urea of additive/ammoniacal liquor mixed solution carry out gas-liquid and contact, the liquid-gas ratio of mixed solution and flue gas is 1.5～4L/m ³, the concentration of ammoniacal liquor in mixed solution is 2%～10%, and the solution concentration of urea in mixed solution is 2%～6%, and mixed solution maintains 5～7 as one-level absorbent solution and its pH value, and temperature is controlled at 30 ℃～60 ℃, the SO in the flue gas ₂And NO _xBe absorbed, sulfite oxidation become ammonium sulfate contacting with flue gas and compressed air takes place to blast in the reacted solution, the addition of above-mentioned additive is 0.005%～0.025% mass percentage content of urea/ammonia spirit;

Second step: remove the solution of carrying secretly in the flue gas after one-level absorbs, make again this flue gas with blending the urea liquid of additive carry out gas-liquid and contact, reaction is finished the back and is discharged, the liquid-gas ratio of flue gas is 5～20L/m after above-mentioned urea liquid and the one-level absorption ³The mass concentration of urea in containing the solution of additive is 4%～13%, and the solution that contains additive maintains 5.5～8 as secondary absorbent solution and its pH value, and temperature is controlled at 30 ℃～60 ℃, the addition of additive is 0.005%～0.025% mass percent of urea liquid

Described additive is one or more the mixture in triethanolamine, ethylenediamine, the phosphamide.

2, mixed solution according to claim 1 is united and is removed sulfur dioxide and nitrogen oxide method, it is characterized in that the flue gas after secondary absorbs, and discharges after demister is removed the liquid of carrying secretly in the flue gas.

3, a kind ofly be used to implement the described mixed solution of claim 1 and unite the device that removes sulfur dioxide and nitrogen oxide method, it is characterized in that by heat exchanger (1), one-level gas distributor (2), one-level absorption reactor thermally (3), one-level demister (4), secondary gas distributor (5), secondary absorption reactor thermally (6), secondary demister (7), secondary circulating pump (10), secondary collecting tank (11), pump (12), centrifuge (13), one-level collecting tank (15), separate liquid pump (16), air compressor machine (17), one-level circulating pump (18) is formed, one-level gas distributor (2) is located in the one-level absorption reactor thermally (3), secondary gas distributor (5) is located in the secondary absorption reactor thermally (6), the exhanst gas outlet of heat exchanger (1) is connected with one-level absorption reactor thermally smoke inlet (21), the flue gas gas outlet of one-level absorption reactor thermally (3) is connected with the smoke air inlet of secondary absorption reactor thermally (6), one-level demister (4) is positioned between the smoke air inlet of the flue gas gas outlet of one-level absorption reactor thermally (3) and secondary absorption reactor thermally (6), secondary demister (7) is located on the secondary absorption reactor thermally exhanst gas outlet (25), one-level collecting tank (15) is located at the below of one-level absorption reactor thermally (3), between the circulation fluid outlet that one-level circulating pump (18) is located at one-level collecting tank (15) and the inlet of one-level absorption reactor thermally (3) and the import of one-level circulating pump (18) be connected with the circulation fluid outlet of one-level collecting tank (15), the outlet of one-level circulating pump (18) is connected with the inlet of one-level absorption reactor thermally (3), secondary collecting tank (11) is located at the below of secondary absorption reactor thermally (6), between the circulation fluid outlet that secondary circulating pump (10) is located at secondary collecting tank (11) and the inlet of secondary absorption reactor thermally (6) and the import of secondary circulating pump (10) be connected with secondary collecting tank (11) circulation fluid outlet, the outlet of secondary circulating pump (10) is connected with the inlet of secondary absorption reactor thermally (6), the ammonium sulfate crystallization solution outlet of one-level collecting tank (15) is connected with the import of centrifuge (13), the liquid outlet of centrifuge (13) with separate liquid pump (16) import and be connected, separating liquid pump (16) outlet is connected with the import of one-level collecting tank (15), the outlet of air compressor machine (17) is connected with the import of one-level collecting tank (15), and the dense ammonium sulfite solution outlet of secondary collecting tank (11) is connected with the import of one-level collecting tank (15) by pump (12).

4, device according to claim 3, it is characterized in that the import that is connected with aqua ammonia pump (19) and one-level collecting tank (15) in the import of one-level collecting tank (15) is connected with the outlet of aqua ammonia pump (19), the import that is connected with ammoniacal liquor Agitation Tank (20) and aqua ammonia pump (19) on aqua ammonia pump (19) is connected with the outlet of ammoniacal liquor Agitation Tank (20).

5, according to claim 3 or 4 described devices, it is characterized in that the import that is connected with urea solution pump (8) and one-level collecting tank (15) in the import of one-level collecting tank (15) is connected with the outlet of urea solution pump (8), the import that is connected with urea liquid Agitation Tank (9) and urea solution pump (8) on urea solution pump (8) is connected with the outlet of urea liquid Agitation Tank (9).

6, device according to claim 3 is characterized in that being provided with valve (14) between the import of the ammonium sulfate crystallization solution outlet of one-level collecting tank (15) and centrifuge (13).

7, device according to claim 3, it is characterized in that the purification of secondary absorption reactor thermally exhanst gas outlet (25) and heat exchanger (1) after the low-temperature flue gas import be connected.

8, a kind ofly be used to implement the described mixed solution of claim 1 and unite the device that removes sulfur dioxide and nitrogen oxide method, it is characterized in that by heat exchanger (1), monoblock type one second reactor, secondary demister (7), secondary circulating pump (10), pump (12), centrifuge (13), separate liquid pump (16), air compressor machine (17), one-level circulating pump (18) is formed, monoblock type one second reactor comprises cylindrical shell (28), a space that is provided with dividing plate (23) and is surrounded by this dividing plate (23) and cylindrical shell (28) in cylindrical shell (28) is one-level absorption reactor thermally (3), another space that is surrounded by this dividing plate (23) and cylindrical shell (28) is secondary absorption reactor thermally (6), on one-level absorption reactor thermally (3), be provided with one-level absorption reactor thermally smoke inlet (21), be provided with one-level gas distributor (2) in the bottom of one-level absorption reactor thermally (3), be connected with one-level collecting tank (15) in the lower end of one-level absorption reactor thermally (3), be provided with one-level demister (4) on the top of one-level absorption reactor thermally (3), in one-level absorption reactor thermally (3) and the below that is positioned at one-level demister (4) be provided with one-level spray thrower (22), and the nozzle of one-level spray thrower (22) is downward, on secondary absorption reactor thermally (6), be provided with secondary absorption reactor thermally exhanst gas outlet (25), be connected with secondary collecting tank (11) in the lower end of secondary absorption reactor thermally (6), be provided with secondary gas distributor (5) on the top of secondary absorption reactor thermally (6), in secondary absorption reactor thermally (6) and be positioned at secondary gas distributor (5) below to be provided with the nozzle of secondary spray thrower (24) and secondary spray thrower (24) downward, one-level demister (4) and secondary gas distributor (5) are by channel connection, the exhanst gas outlet of above-mentioned heat exchanger (1) is connected with one-level absorption reactor thermally smoke inlet (21), secondary demister (7) is located on the secondary absorption reactor thermally exhanst gas outlet (25), between the circulation fluid outlet that one-level circulating pump (18) is located at one-level collecting tank (15) and the inlet of one-level spray thrower (22) and the import of one-level circulating pump (18) be connected with the circulation fluid outlet of one-level collecting tank (15), the outlet of one-level circulating pump (18) is connected with the inlet of one-level spray thrower (22), between the circulation fluid outlet that secondary circulating pump (10) is located at secondary collecting tank (11) and the inlet of secondary spray thrower (24) and the import of secondary circulating pump (10) be connected with secondary collecting tank (11) circulation fluid outlet, the outlet of secondary circulating pump (10) is connected with the inlet of secondary spray thrower (24), the outlet of secondary circulating pump (10) is connected with the inlet of secondary absorption reactor thermally (6), the ammonium sulfate crystallization solution outlet of one-level collecting tank (15) is connected with the import of centrifuge (13), the liquid outlet of centrifuge (13) with separate liquid pump (16) import and be connected, separating liquid pump (16) outlet is connected with the import of one-level collecting tank (15), the outlet of air compressor machine (17) is connected with the import of one-level collecting tank (15), and the dense ammonium sulfite solution outlet of secondary collecting tank (11) is connected with the import of one-level collecting tank (15) by pump (12).

9, a kind ofly be used to implement the described mixed solution of claim 1 and unite the device that removes sulfur dioxide and nitrogen oxide method, it is characterized in that by heat exchanger (1), monoblock type one second reactor, secondary demister (7), secondary circulating pump (10), pump (12), centrifuge (13), separate liquid pump (16), air compressor machine (17), one-level circulating pump (18) is formed, monoblock type one second reactor comprises cylindrical shell (28), a space that is provided with dividing plate (23) and is surrounded by this dividing plate (23) and cylindrical shell (28) in cylindrical shell (28) is one-level absorption reactor thermally (3), another space that is surrounded by this dividing plate (23) and cylindrical shell (28) is secondary absorption reactor thermally (6), on one-level absorption reactor thermally (3), be provided with one-level absorption reactor thermally smoke inlet (21), be provided with one-level gas distributor (2) in the bottom of one-level absorption reactor thermally (3), be connected with one-level collecting tank (15) in the lower end of one-level absorption reactor thermally (3), be provided with one-level demister (4) on the top of one-level absorption reactor thermally (3), be provided with one-level fluid column formula injector (26) in one-level absorption reactor thermally (3) bottom and above being positioned at one-level gas distributor (2), and the nozzle of one-level fluid column formula injector (26) upwards, on secondary absorption reactor thermally (6), be provided with secondary absorption reactor thermally exhanst gas outlet (25), be connected with secondary collecting tank (11) in the lower end of secondary absorption reactor thermally (6), be provided with secondary gas distributor (5) on the top of secondary absorption reactor thermally (6), the nozzle that is provided with secondary fluid column formula injector (27) and secondary fluid column formula injector (27) in the bottom of secondary absorption reactor thermally (6) makes progress, one-level demister (4) and secondary gas distributor (5) are by channel connection, the exhanst gas outlet of above-mentioned heat exchanger (1) is connected with one-level absorption reactor thermally smoke inlet (21), secondary demister (7) is located on the secondary absorption reactor thermally exhanst gas outlet (25), between the circulation fluid outlet that one-level circulating pump (18) is located at one-level collecting tank (15) and the inlet of one-level fluid column formula injector (26) and the import of one-level circulating pump (18) be connected with the circulation fluid outlet of one-level collecting tank (15), the outlet of one-level circulating pump (18) is connected with the inlet of one-level fluid column formula injector (26), between the circulation fluid outlet that secondary circulating pump (10) is located at secondary collecting tank (11) and the inlet of secondary fluid column formula injector (27) and the import of secondary circulating pump (10) be connected with secondary collecting tank (11) circulation fluid outlet, the outlet of secondary circulating pump (10) is connected with the inlet of secondary fluid column formula injector (27), the outlet of secondary circulating pump (10) is connected with the inlet of secondary absorption reactor thermally (6), the ammonium sulfate crystallization solution outlet of one-level collecting tank (15) is connected with the import of centrifuge (13), the liquid outlet of centrifuge (13) with separate liquid pump (16) import and be connected, separating liquid pump (16) outlet is connected with the import of one-level collecting tank (15), the outlet of air compressor machine (17) is connected with the import of one-level collecting tank (15), and the dense ammonium sulfite solution outlet of secondary collecting tank (11) is connected with the import of one-level collecting tank (15) by pump (12).

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