JP2001079572A - Pressure control method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To control and correct the flow rate of inflow water to be treated into an ozone contact pond by measuring the gas pressure (Δp) inside a waste ozone line. SOLUTION: This method comprises: measuring the gas pressure 13 inside a waste ozone sample line; receiving the actual measured value of the gas pressure 13 in a pressure-correcting calculation section 14; and applying correction for the flow rate control of lifted water to a lift pump suction wall water level or to a flow rate controlling calculation section 11 both functioning as a control system of a lift pump 2, by the pressure-correcting calculation section 14, accordingly to the gas pressure 13 inside the waste ozone sample line. Thus, by measuring the gas pressure 13 (Δp) inside the waste ozone line and controlling the inflow water to be treated into an ozone contact pond, the operation control of an advanced treatment equipment can stably and safely be performed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to the treatment of gaseous exhaust ozone released from an ozone contact pond in advanced treatment for treating tap water, sewage and industrial waste water with ozone.
BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pressure control method that enables stable and complete treatment without leakage of ozone irrespective of a change in the flow rate of treated water.

[0002]

2. Description of the Related Art In recent years, eutrophication has been progressing due to water pollution in lakes, marshes, rivers, and the like that serve as water intake sources. For this reason,
Plankton and algae are abnormally breeding, and the unpleasant taste of the water supply has become a problem.

As a countermeasure, advanced treatment including ozone treatment and activated carbon treatment is suitable, and is adopted in many water purification plants. The conventional flow control of the inflow of the ozone contact pond is a constant control of the water level of the pumping well at the front stage of the ozone contact pond, that is, a constant control of the inflow and outflow of the pumping well.

[0004] Further, the waste ozone treatment apparatus is an automatic alternate operation using a timer for each apparatus. As described above, in the conventional control, since the pressure factor is not incorporated in the control system, there is a high possibility that the ozone discharged by the mist separator leaks from the drain water tank together with the mist.

When a person inhales air containing ozone, it reaches the alveoli via the trachea, causing emphysema.

The recommendation on the ozone permissible concentration in the environment of the Japanese industry is 0.1 ppm.

For this reason, each time an ozone leak is detected, the ozone generator is stopped, and there are many operational problems.

Conventionally, as an exhaust ozone treatment apparatus, there has been proposed an improvement relating to a heater (Japanese Patent Laid-Open No. Hei 10-146518) and a proposal regarding the display of deterioration of a decomposition tower catalyst (Japanese Patent Laid-Open No. Hei 11-070321). No proposal for flow control has been found.

[0009]

The internal pressure in the upper section of the ozone contact pond changes depending on the flow rate flowing into the ozone contact pond.

Further, since the gas is pulled out from the upper portion, the gas pressure in the exhausted ozone sample pipe is affected, and this pressure change is one of the causes of ozone leakage.

Since the leaked ozone has an adverse effect on the human body, ozone should not be leaked.

Therefore, it is necessary to measure the gas pressure in the exhaust ozone sample tube and control the flow rate of the water to be treated flowing into the ozone contact pond.

The present invention has been made in view of the above-mentioned problems of the prior art, and an object of the present invention is to provide a pressure control method capable of operating a sophisticated processing facility stably and safely.

[0014]

In order to achieve the above object, the present invention measures the pressure in the space above the ozone contact pond and incorporates it into the constant level control system of the pump for inflow of the ozone contact pond. Pressure control to prevent leakage.

Further, even if the gas pressure in the exhausted ozone sample tube shows a high value, the mist separator can be multi-staged so that the mist can be removed without leakage of ozone due to the pressure loss of the mist separator itself.

In the above-mentioned means constituting the present invention, it is important to stably and safely operate and manage the advanced processing equipment without leaking the ozone waste.

The inventors of the present invention should perform gas-liquid separation with a mist separator which is a part of the waste ozone treatment apparatus. However, as the pressure in the space above the ozone contact pond increases, the waste ozone flows out and leaks simultaneously with the mist. This was found in a field test, which led to the present invention.

The drain separated by the mist separator is led to a drain tank by a drain pipe. It was found that there was ozone leakage due to the water head due to the liquid level in the drain tank and the gas pressure balance in the exhaust ozone sample tube.

The waste ozone treatment apparatus generally comprises a mist separator, a suction fan, a heater, and a waste ozone decomposition tower, and is installed on the same foundation and packaged.

Therefore, it is not easy to change the design of the drain tank.

To prevent ozone leakage from the drain tank,
It is necessary to keep the state of the water head (Δh)> the gas pressure (Δp) in the drained ozone sample tube due to the liquid level in the drain tank.

Gas pressure in exhaust ozone sample tube (Δp)
Is proportional to the internal pressure in the space above the ozone contact pond. Also, the internal pressure in the space above the ozone contact pond depends on the fluctuation of the ozone contact pond water level caused by the change of the ozone contact pond inflow rate.

Accordingly, since the gas pressure (Δp) in the exhaust ozone pipe is influenced by the flow rate of the ozone contact pond, the flow rate of the ozone contact pond is controlled by the gas pressure (Δp) in the exhaust ozone sample pipe. By performing control so as to maintain the state of Δh> Δp, ozone leakage from the drain tank can be prevented, and stable and safe operation management can be performed.

[0024]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to FIG.

FIG. 1 shows an example of application to an advanced treatment facility comprising a pumping pump facility, an ozone contact pond facility, and a waste ozone treatment facility. 1 is treated water, 2 is a pump, 3 is a water level gauge, 4 is the space above the ozone contact pond, 5 is an ozone generator, 6
Is a waste ozone sample tube, 7 is a waste ozone treatment facility, 8 is a drain pipe, and 9 is a drain water tank.

The water 1 to be treated flows into a pumping well and is guided to an ozone contact pond 4 by a pumping pump 2. Ozone contact pond
In 4, the ozonized air produced in the ozone generator 5 and the water to be treated are mixed in a gas-liquid state, and dissolved in the water to be treated as a part of dissolved ozone. The ozonized air that has not been melted stays in the space above the ozone contact pond as exhausted ozone, and is guided to the exhausted ozone treatment facility 7 by a suction fan included in the exhausted ozone treatment facility 7.

The gas pressure 13 in the exhaust ozone sample pipe is measured. Upon receiving the value of the measured pressure 13, the pressure correction calculation unit 14 corrects the pump pump well level or the flow rate control calculation unit 11, which is the control system of the pump, based on the gas pressure in the exhaust ozone sample pipe, and controls the pump speed control unit. Command the rotation speed of each pump calculated from the required flow rate to 12.

FIG. 2 shows the details of the waste ozone treatment apparatus.

Exhaust ozone gas 15 from each ozone contact pond is collected in a header pipe 16, measured by a gas pressure gauge 17 in an exhaust ozone sample pipe, and led to a mist separator 18. In the mist separator 18, water droplets (mist) accompanying the exhausted ozone gas 15 are separated and guided to a drain water tank 19. The exhaust ozone gas from which the mist has been removed is heated by the decomposition tower heater 20, and the ozone is decomposed into oxygen in the exhaust ozone decomposition tower 21 and released to the atmosphere.

FIG. 3 shows details of the multi-stage mist separator ozone treatment apparatus.

The discharged ozone gas is supplied to the mist separator 1st stage 18-
1, mist separator 2 stage 18-2, mist separator n stage 1
It is separated into mist and exhausted ozone gas through 8-n.

[0032]

According to the present invention, the operation management of the advanced treatment equipment can be stably and safely controlled by measuring the gas pressure (Δp) in the exhaust ozone pipe and controlling the flow rate of the water to be treated flowing into the ozone contact pond.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of an advanced water purification treatment process showing one embodiment of the present invention.

FIG. 2 is a detailed view of an exhaust ozone treatment device.

FIG. 3 is a detailed view of a multi-stage mist separator ozone treatment apparatus.

[Explanation of symbols]

1 ... Water to be treated, 2 ... Pump, 3 ... Pump water level gauge, 4 ... Ozone contact pond upper space, 5 ... Ozone generator, 6
... waste ozone sample tube, 7 ... waste ozone treatment equipment, 8 ... drain pipe, 9 ... drain water tank, 10 ... setting device, 11 ... water level (flow rate) control calculation unit, 12 ... speed control device, 13 ... inside the waste ozone sample tube Gas pressure detection end, 14 ... pressure compensation control device,
15… Exhaust ozone gas, 16… Ozone header tube, 17… Gas pressure detection end in exhaust ozone sample tube, 18… Mist separator,
18-1: Mist separator 1 stage, 18-2: Mist separator 1 stage, 18-n: Mist separator n stage, 19: Drain water tank, 20: Decomposition tower heater, 21: Waste ozone decomposition tower.

Continued on front page F term (reference) 4D050 BB02 BD04 BD06 BD08 5H307 AA08 BB06 DD17 EE22 FF12 FF16 GG20 5H309 AA07 BB18 CC04 CC09 DD04 DD27 EE04 FF17 GG03 HH21 JJ06 5H316 AA07 DD17 EE22 FF01 H11 FF24GG

Claims (2)

[Claims] 1. An ozone contact pond in which ozonized air and treated water are brought into gas-liquid contact with each other. A pressure control method, comprising: a means for correcting and calculating a flow rate, wherein the flow rate of inflow into an ozone contact pond is controlled by the pressure of exhaust ozone. 2. The exhaust ozone treatment apparatus according to claim 1, wherein the mist separator is provided in multiple stages to prevent ozone leakage from the mist separator drain tube.