JPS61257289A - Controlling method for airflow of air compressor - Google Patents

Abstract

PURPOSE:To always permit appropriate control of air flow to be fed to a wet oxidizing device by measuring continuously oxygen concn. in the exhaust air discharged after completion of the reaction and feeding back the measured results to a butterfly valve provided before a compressor for feeding air. CONSTITUTION:When desulfurizing liquid of coke oven gas, several urban waste water or industrial waste water is oxidized with air at high temp. and under high pressure in a wet oxidizing device 3, the concn. of oxygen in the exhaust gas discharged after completion of the reaction is measured continuously, and the measured results are fed back to a butterfly valve 6 provided before a compressor for feeding air to control thus the amt. of the air to be fed. Thus, the amt. of the air to be fed to the wet oxidizing device is always controlled appropriately, and the oxidation efficiency is held stably and the power of the air compressor can be saved. Accordingly, stabilization of operation is realized by this method, and an economically rational process is provided.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention oxidizes waste liquid, domestic wastewater, industrial wastewater, etc. generated from a desulfurization equipment for -gas furnace gas with air at high temperature and high pressure to produce ammonium sulfate mother liquor. The present invention relates to a method for controlling the air volume of an air compressor in a wet oxidation device, etc., which detoxifies the harmful substances contained in the collected waste.

[Conventional technology]

Air volume control methods for air compressors in wet oxidation equipment, etc. can be roughly divided into continuous methods and step-by-step methods. More specifically, (1) compressed air is transferred to the intake side using a bypass valve. There are two methods: (2) a method of changing the rotation speed of the compressor drive source; (3) a method of controlling by opening the intake valves of each stage.

These methods are adopted as appropriate depending on the location and operating conditions of the wet oxidation apparatus.

[Problem that the invention seeks to solve]

However, each of the conventional control methods described above has the following problems.

In other words, (1) The method of returning part or all of the compressed air to the intake side using a bypass valve makes it possible to steplessly and continuously adjust the air volume within the range of 100% to 0%. However, the loss of driving power is large regardless of the load of the air compressor.

(2) A method of changing the rotational speed of the compressor drive source is available for swivel and diesel drives, but it is difficult to use for conductive drives due to the complexity of the equipment and the cost of modification.

(3) The method of opening/closing and controlling the intake valves at each stage is to open all or half of the intake valves using air or hydraulic pressure, so the amount of adjustment is variable such as 0%, 50%, and 100%. Since it is a continuous step-by-step method, it is not possible to make continuous fine adjustments to load fluctuations.

That is what it is.

In addition, the outlet of the air compressor (i.e. the inlet side 5r of the system)
: There is also a method of opening the pressure regulating valve that is closed and blowing air before charging into the system to adjust the amount of air. However, since the air volume is adjusted after the air compressor, the compressor k
There is a drawback that such power cannot be reduced.

[Means for solving problems]

The present invention eliminates the runner-up problems in the conventional method as described above,
As a result of various studies to establish a method that can send the desired amount of air when needed, we continuously measured the oxygen concentration in the exhaust gas discharged after the reaction, and the results were sent to an air compressor. This is a method for controlling the air volume of an air compressor, which is characterized by controlling the amount of air supplied by feeding back the information.

[Effect]

In the present invention, the oxygen concentration in the exhaust gas discharged after the completion of the reaction is continuously measured, and the amount of oxygen supplied to the wet oxidizer or the like is adjusted using a butterfly valve provided in front of the air compressor.

When determining oxidation efficiency, conventionally the properties of the liquid after the reaction is completed (
For example, tfscN%81o, ) was analyzed using methods other than titration, but it takes time to measure and the measurement frequency is limited, making it almost impossible to grasp the current situation. Furthermore, since the amount of air supplied cannot be adjusted, excessive air supply is often required, leading to deterioration of oxidation efficiency.

In the air volume control method of the present invention, a butterfly valve is installed in the pipeline between the suction strainer and the air compressor, and an oxygen concentration meter probe is installed in the exhaust gas cleaning tower to measure the oxygen concentration in the exhaust gas after the reaction is completed. input the oxygen concentration data in the exhaust gas detected by the probe into the computer,
The amount of air is controlled by automatically adjusting the opening and closing of the butterfly valve according to a preset program.

〔Example〕

Hereinafter, an example in which the method of the present invention is applied to an actual coke oven gas desulfurization liquid wet oxidation apparatus will be shown with reference to the drawings, and its configuration and effects will be specifically explained.

FIG. 1 is a schematic diagram showing an air flow path around a wet oxidizer constructed according to the present invention, in which 1 is an air suction strainer, 2 is a compressor, 6 is a wet oxidizer, 4 is a scrubber, and 5 is a 6 is a control valve (butterfly valve), and 7 is an arithmetic processing unit.

Although not shown, a probe for detecting the oxygen concentration in the exhaust gas is inserted into the gas chamber above the scrubber 4. Information is transmitted from this probe to the oxygen concentration meter 5, where it is quantified. , the arithmetic processing unit 7 is configured to output a Vc signal.

After processing the input signal in this arithmetic processing unit 7, a signal is issued to command the opening and closing of the regulating valve 6 according to a preset program, and the control valve 6 is controlled to open and close. The driving source for opening and closing the valve 6 may be pneumatic or hydraulic. Next, the air volume t- sucked in by the air suction strainer 1 is
When adjusting with the control valve 6, it is naturally thought that the temperature of the discharge valve and the suction pressure will increase.

In order to confirm this relationship, we investigated the degree of temperature rise at the first stage valve using a horizontally opposed compressor as schematically shown in Figure 2. 1.1...V is the first stage.

2nd stage... Indicates the 5th stage compressor, T11T! ...
T. indicates a discharge valve, and although this discharge valve is not shown, it is also provided in the second and subsequent stage compressors.

As is clear from the results in the table, the temperature rise of the first-stage discharge valve is only about 120°C at most when measuring six valves, which is not a particularly high temperature during actual operation. It turned out that there was no problem with the equipment.

In terms of suction pressure, suction valve (butterfly valve),
It is recognized that the reduction in driving power is greater in the case where the adjustment is made, compared to the case where the adjustment is not made.

〔Effect of the invention〕

Himi F! By implementing A, it is possible to always appropriately adjust the amount of air supplied to the wet oxidizer K.
It has become possible to maintain stable oxidation efficiency and to save power for the air compressor.

Therefore, this method can be said to be an economically rational method that can stabilize the operation.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram showing peripheral equipment of a wet oxidation apparatus, and FIG. 2 is a schematic diagram showing a combination of air compressors. 1... Suction strainer, 2... Compressor, 3...
Wet oxidizer, 4...Scrubber, 5...Oxygen concentration meter, 6...Control valve, 7...Arithmetic device.

Claims (1)

[Claims] When using wet oxidation equipment to air oxidize coke oven gas desulfurization liquid and various domestic and industrial wastewater under high temperature and high pressure,
After the reaction is complete, the oxygen concentration in the exhaust gas is continuously measured.
A method for controlling air volume of an air compressor, characterized in that the result is fed back to a butterfly valve provided in front of the air supply compressor to control the amount of air to be supplied.