JPH02126920A - Apparatus for controlling desulfurization - Google Patents

Abstract

PURPOSE:To sufficiently execute desulfurization by controlling flow rate of water from a nozzle so that the detected temp. with temp. detector comes to more than the dew point calculated with a dew point arithmetic means. CONSTITUTION:The water is injected to combustion gas from the nozzle 8 to execute the desulfurization. Then, steam partial pressure contained in the combustion gas at downstream side from the nozzle 8 is calculated with the dew point arithmetic means 17 and based on this steam partial pressure, the dew point is calculated. Further, temp. of exhaust gas at downstream side from the nozzle 8 is detected with the temp. detector 16. Further, in a means composed of control circuits 18, 20, pump 12, flow rate control valve 14, flow meter 15, etc., the flow rate of water from the nozzle 8 is controlled so that the temp. detected with the temp. detector 16 comes to more than the dew point calculated with the dew point arithmetic means 17. In this result, SOx concn. can be reduced and also damage of corrosion caused by excess-supplying of the water is prevented and the desulfurization can be executed.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention is directed to SOx contained in combustion gas from a combustion furnace, etc.
This invention relates to a desulfurization control device for reducing.

BACKGROUND ART Conventionally, in order to perform desulfurization, water is injected into the combustion gas from a combustion furnace to clean it, thereby reducing SOx. If too much water is injected, equipment will corrode, so in order to prevent this corrosion, the injected water must be adjusted so that the temperature of the combustion gas at the point where the water is injected is above the dew point, regardless of load fluctuations. The flow rate is kept low.

Problems to be Solved by the Invention With such prior art, it is difficult to sufficiently reduce the concentration of SOx contained in combustion gas.

An object of the present invention is to provide a desulfurization control device that can perform sufficient desulfurization.

Means for Solving the Problems The present invention provides a desulfurization control device that performs desulfurization by injecting water into combustion gas from a nozzle. a dew point calculation means for calculating a dew point based on the pressure; a temperature detector for detecting the temperature of the exhaust gas downstream of the nozzle; This desulfurization control device is characterized in that it includes means for controlling the flow rate of water from the nozzle.

According to the present invention, water is injected from a nozzle into combustion gas from a combustion furnace, etc., the water vapor partial pressure contained in the combustion gas after the water injection is calculated, and the dew point is determined based on this water vapor partial pressure. seek. so that the temperature is maintained above this dew point.
Controls the flow rate of water jet from the nozzle. This allows for efficient desulfurization without causing corrosion due to too much water.

Example No. 11121 is a sectional view of one embodiment of the present invention.

In the combustion furnace 1, kerosene is supplied from a pipe 2 for starting, pulverized coal is supplied from a pipe 3, and further from a pipe 4.
Combustion air is supplied from In the combustion chamber 5 of the combustion furnace 1, kerosene and pulverized coal are combusted, and the combustion gas is led from a pipe 6 to a spray cooler 7, where it is washed and desulfurized by water injected from a nozzle 8. This combustion gas with reduced SOx is passed from the bag filter 9 to the chimney 10 via the pipe line 10.
I am guided by 1.

Water from the pump 12 passes through a pipe 13 to a flow rate control valve 14.
The flow rate is controlled by the following and supplied to the nozzle 8. The flow rate of this water is measured by an 11ml meter 15. The temperature of the combustion gas downstream of the nozzle 8 is
The temperature is detected by the temperature detector 16.

FIG. 2 is a block diagram showing the electrical configuration of the embodiment shown in FIG. 1. The dew point calculating means 17 calculates and obtains the dew point of the combustion gas after water is injected from the nozzle 8. The setting signal determined by considering the calculated dew point is line 3.
1 to a control circuit 18 that performs proportionality, integration, etc.

The output from the temperature detector 16 is given to the control circuit 18 . The control circuit 18 derives a signal representing the deviation between the dew point calculated by the dew point calculation circuit 17 and the temperature detected by the temperature detector 16 to one line, and sends it to a control circuit 20 that performs proportionality, integration, etc. give. Control circuit 20
is given the measured flow rate of water in the nozzle 8 measured by the flow meter 15. This control circuit 20 controls the flow rate of water controlled by the flow control valve 14, that is, the flow meter 1.
The flow rate of water measured by 5 is controlled to such a flow rate that the temperature deviation from the control circuit 18 through one line is zero. In this way, the temperature detected by the temperature detector 16 is maintained at or above the dew point of water vapor. In this way, SOx
The concentration is efficiently reduced, and there is no risk of corrosion of the spray cooler 7, bag filter 9, etc. due to too much water.

No. 31121 is a block diagram showing a specific configuration of the dew point calculation circuit 17. The flow rate of kerosene supplied from conduit 2 is measured by a kerosene flowmeter 22, and the flow rate of pulverized coal supplied from conduit 3 is measured by a pulverized coal flowmeter 23, which is further supplied from conduit 4. The flow rate of combustion air is measured by an air flow meter 24. The inlet steam flow rate calculation circuit 25 calculates the adhering moisture and inherent moisture of the pulverized coal flow meter 23, calculates the amount of water generated by the combustion of the kerosene and pulverized coal, and further calculates the amount of water contained in the air. In this way, the flow rate of water contained in the combustion gas discharged from the combustion furnace 1 is determined and provided to the addition circuit 26.

A signal representing the flow rate of spray water measured by the flow meter 15 is given to the addition circuit 26 . In this way, adder circuit 2
6 is a water vapor partial pressure calculation circuit 27 which outputs a signal representing the total amount of water contained in the combustion gas downstream of the spray cooler 7.
give to The water vapor partial pressure calculating circuit 27 calculates the water vapor partial pressure of the combustion gas, and calculates the water vapor partial pressure of the combustion gas through the steam front passage 28 to determine the saturated temperature, that is, the dew point T, corresponding to the water vapor partial pressure based on the saturated steam diagram 11 as shown in the fourth factor. seek. Steam front road 28
A signal representing the dew point from is given to an adder circuit 29.

The addition circuit 29 includes a circuit 30 for setting a predetermined value α.
A signal is given from This predetermined value α is intended to reliably prevent the temperature of the combustion gas from falling below the dew point due to the amount of water injected from the nozzle 8 being too large, and to prevent the occurrence of rK eclipse. The signal derived from the adder circuit 29 to the line 31 is given to the control circuit 18 as the target value of the combustion gas temperature at the outlet of the bag filter 9, as described above.

Referring to FIG. 5, it has been confirmed through experiments by the inventor that the desulfurization efficiency η of the combustion gas reaches its maximum at a temperature higher than the dew point T by a predetermined value α1. Therefore, it is also possible to improve the desulfurization efficiency by setting the above-mentioned predetermined value α=α1.

Effects of the Invention As described above, according to the present invention, it is possible to reduce the SOx concentration and perform desulfurization while preventing damage such as corrosion due to excessive water supply.

[Brief explanation of drawings]

FIG. 1 is a sectional view of an embodiment of the present invention, FIG. 2 is a block diagram showing the electrical configuration of an embodiment of the invention, and FIG. 3 is a block diagram showing the specific configuration of the dew point calculation circuit 17. , FIG. 4 is a graph showing the configuration of the steam table circuit 28, and FIG. 5 is a graph showing the relationship between combustion gas temperature and desulfurization efficiency. DESCRIPTION OF SYMBOLS 1... Combustion furnace, 7... Suaretara, 8... Nozzle, 12... Pump, 14... Flow rate control valve, 15...
...Flowmeter, 16...Temperature detector, 17...Dew point calculation circuit, 18°20...Control circuit, 25...Inlet water vapor flow rate calculation circuit, 27...Water vapor partial pressure calculation circuit, 28
...Steam table circuit, 30...Setting circuit agent Patent attorney Number of strokes Keiichi Diagram Diagram Water vapor partial pressure Diagram Temperature

Claims (1)

[Claims] In a desulfurization control device that desulfurizes combustion gas by injecting water from a nozzle, the water vapor partial pressure contained in the combustion gas downstream of the nozzle is calculated, and the dew point is determined based on this water vapor partial pressure. a temperature detector that detects the temperature of the exhaust gas downstream of the nozzle; and a temperature detector that detects the temperature of the exhaust gas on the downstream side of the nozzle, the temperature detected by the temperature detector being equal to or higher than the dew point calculated by the dew point calculation means. and means for controlling the flow rate of water from the nozzle.