JPS60181211A - Method for changing over control of furnace top pressure - Google Patents

Abstract

PURPOSE:To recover the energy retained by a reactive gas by using a turbine by interposing a function to control furnace top pressure by a bypass valve and performing automatically change-over between the functions to control the furnace top pressure for a gas scrubber and a turbine. CONSTITUTION:A reactive gas scrubber 5, an expansion turbine 9 and a bypass valve 12 provided in a gas flow passage bypassing said turbine are provided to control the top pressure of a reaction furnace 3. A slight difference is given between the set furnace top pressures indicated by a furnace top pressure setter 13 to the respective control mechanisms for said scrubber 5 and valve 12 in such chemical reaction system. The competence for function participating in the control of the furnace top pressure is changed over while both control functions are kept operating.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for switching the top pressure control of a reactor.

As a prior art related to a switching method for controlling the top pressure of a chemical reactor, there is a patent application published by the same applicant. ≦−? There is a θ♂ model, and its content is that the furnace top pressure control function is provided to both the septum valve and the gas turbine, and a slight difference is created between the furnace top pressure settings of both. The purpose is to automatically switch the control function from one side to the other, and the septum valve and the gas turbine installed in parallel with it were selected as the objects to which one control function is provided.

The device of the present invention has selected a reaction gas cleaning device, a gas turbine installed downstream thereof, and a bypass valve of the gas turbine as objects to be provided with this function, and is different from that of the earlier application. Although there are some similarities in purpose and effect, they are completely different in structure. That is, in the present invention, the switching operation between the furnace top pressure control function by the reaction gas cleaning device and the furnace top pressure control function by the turbine bypass valve is performed extremely smoothly and automatically, and moreover, the cleaning function of the reaction gas cleaning device is The purpose is to provide a switching method that enables recovery of the energy possessed by a reaction gas using an expansion turbine under a stable condition, and as a means for that purpose, a reaction gas cleaning device is used. By creating a slight difference between the furnace top pressure setting values instructed by the furnace top pressure setting device for the control function provided by the bypass valve and the control function provided by the bypass valve, both of the above control functions are activated. I was in a state of
At the same time, the responsibility for the function related to the control of the furnace top pressure is switched from one side to the other, or from one reaction gas cleaning device to the other bypass valve. Automatically switch to constant differential pressure control that operates so as not to exceed the differential pressure across the cleaning device that is necessary to maintain the function of the cleaning device, or limit the opening by the upper limit, or furthermore, the other reaction from the 10,000 bypass valve. By switching responsibility for the above-mentioned functions to the gas scrubbing device, the reaction gas scrubbing device is equipped with a configuration sound characterized by switching from constant differential pressure control and/or restriction by upper limit opening to furnace top pressure control.

The figure shows an embodiment of the present invention, where / is a blower, λ is a hot blast furnace, 3 is a blast furnace, G is a dust catcher, Y is a gas cleaning device, O is a turbine population valve, 7 is a main blocking valve, ? is a speed governor valve, ri is a gas turbine, /θ is a generator directly connected to the gas turbine, and // is a turbine exit valve. /2 is a bypass valve, the opening and closing of which is controlled by the furnace top pressure control device B. A differential pressure detector for input, /! is a turbine rotation speed detection device that inputs the detected rotation speed to the turbine governor J. A is a furnace top pressure setting device, and a bypass valve furnace top pressure control device B.

This is for instructing the furnace top pressure set value to each of the gas cleaning device furnace top pressure control device C1 and the turbine governor J. The furnace top pressure detected by the furnace top pressure detector/3 is transmitted to each of the bypass valve furnace top pressure control device B1, the gas cleaning device furnace top pressure control device C1, and the turbine governor J, and is compared with the set value before being determined. issues commands to the control function target. E is the furnace top pressure control changeover switch, which switches the target to which the control function is applied between the bypass valve/2 and the gas cleaning device, and changes the set value of the pressure deviation setting device toward the target on the non-selected side. It should not be sent.

G is a low selector which selects a low value among the respective control values of the furnace top pressure control device C and the differential pressure control device F of the gas scrubbing device, and then controls the gas # and amount of the gas scrubbing device O. H is a differential pressure setting device for the differential pressure control device F, K is a valve opening limiter for the turbine governor J, and L is a load setting device for the turbine governor J.

Next, the operation of the method of the present invention having the above configuration will be explained. Initially, it is assumed that the furnace top pressure is controlled by the gas scrubber.

At this time, the detected value of the differential pressure detector/G is larger than the set value of the differential pressure setting device H, so the low selector G is used to control the output of the furnace top pressure control device C of the gas cleaning device. is selected to open and close the gas scrubber and control the furnace top pressure.

On the other hand, the setting value of the bypass valve furnace top pressure control device B is the value obtained by subtracting the value of the pressure deviation setting device from the setting value of the furnace top pressure setting device A, so it is smaller than the furnace top pressure, and the bypass valve /2 is in a fully open state. In addition, the gas turbine 9 is stopped, and the turbine population valve O and the turbine outlet valve
/ is fully open, and the main blocking valve 7 and speed regulating valve are fully closed.

In this state, when the furnace top pressure control switch E is switched to the gas cleaning device furnace top pressure control device CnI in order to switch the furnace top pressure to the bypass valve/2 side, the set value is changed to the setting value of the furnace top pressure setting device A. The setting value of the pressure deviation setting device is reduced, and it becomes lower than the furnace top pressure, so the on-off valve 14 of the gas cleaning device opens, the differential pressure decreases, and the furnace top pressure also decreases. The furnace top pressure will try to drop to the set value of the control device C.

Bypass valve furnace top pressure control device B closes the bypass valve when its set value becomes equal to the set value of furnace top pressure setting device A, and the furnace top pressure becomes lower than the set value. The pressure (hereinafter referred to as turbine inlet pressure) is increased to maintain the furnace top pressure. Since the bypass valve/2 controls the furnace top pressure, the gas scrubber furnace top pressure control device C opens in an attempt to lower the furnace top pressure to a value that is less than the set value of the pressure deviation setting device, and the difference between the furnace top pressure and The pressure drops further and further, and the bypass valve closes in an attempt to compensate, causing the turbine inlet pressure to rise. When the differential pressure of the gas cleaning device finally becomes smaller than the set value of the differential pressure setting device H, the low selector G selects the output of the differential pressure control device F of the gas cleaning device to adjust the gas pressure to maintain the differential pressure. Gas cleaning equipment that controls the opening/closing valve/≦ of the cleaning equipment! switches to constant differential pressure control. In this way, the gas cleaning device is switched to constant differential pressure control, and the bypass valve/2 is switched to furnace top pressure control.

Next, method V of the earlier application (Tokuko Shoj Otsu-♂θzako No.)
From C, start the turbine and switch to turbine top pressure control.
exchange.

Fully open the main stop valve 7, increase the valve opening limiter K,
When the speed regulating valve ♂ of the turbine governor J is opened, the gas turbine motor begins to rotate. Turbine rotation speed detection device/
! The output of θ is given to the turbine governor J to control the rotation speed of p using the regulating valve r, and when the frequency of the generator/θ matches the frequency of the grid, the generator circuit breaker is closed, and from then on, the load setter As a result, the generator output is increased.

The other day, the regulating valve? is gradually opened, and bypass valve/2 is closed while controlling the furnace top pressure. When the generator output is further increased using the load setting device, the bypass valve/
2 is fully closed and the furnace top pressure control function is lost.The turbine governor J sets the furnace top pressure set value for the turbine to a value that is slightly lower than the human set value (hereinafter referred to as the front pressure setting). (referred to as value)
If the top pressure of the furnace is about to drop below the pre-pressure setting value, the regulating valve will be activated. is closed to maintain furnace top pressure. Continuous operation of the turbine is performed using constant differential pressure control for the gas scrubber, fully closed bypass valve, and furnace top pressure control for the governor valve.

In this case, in place of the constant pressure differential applied to the gas cleaning device, the operation of the device may be limited by the upper limit opening of the on-off valve built into the device. , M is for gas cleaning equipment! This is an upper limit opening setting device for instructing the upper limit value of the opening for the built-in on-off valve/B. The opening limit by the upper limit opening setting device may be used in place of the limit by the constant difference ratio, or both limits may be used at the same time. The figure shows an example where both restrictions are used together.

When the turbine is stopped, the load setting value is first reduced and the regulating valve is activated. operate to close. The turbine inlet pressure increases and the gas cleaning device! Since the furnace performs constant differential pressure control, when the furnace top pressure rises and reaches the set value of the furnace top pressure setting device A, the bypass valve /
2 begins to open from the fully closed position to control the furnace top pressure. When the load setting value is decreased and the lower limit is reached, power generation Jt! A1
0 is opened, then the valve opening degree limiter K is decreased to close the speed regulating valve ♂. When the regulating valve t is fully closed, a trip signal is issued to fully open the main blocking valve 2. During this time, the bypass valve 12 opens while controlling the furnace top pressure.

Then, when the furnace top pressure control changeover switch E is switched again to the bypass valve furnace top pressure control device B side, the set value is the set value of the furnace top pressure setting device A minus the setting value of the pressure deviation setting device B. Since this is lower than the furnace top pressure, the bypass valve/2 opens and the turbine inlet pressure decreases. At this time, gas cleaning equipment! is performing constant differential pressure control, but when the furnace top pressure decreases due to a decrease in the turbine inlet pressure, the furnace top pressure control device C of the gas cleaning device uses the furnace top pressure setting device A as the set value. , Immediately select the furnace top pressure-expansion side with the low selector G and turn on the gas cleaning device! The on-off valve/B is closed to maintain the furnace top pressure. The bypass valve /2 opens further in an attempt to lower the furnace top pressure to the set value of the pressure deviation setting device B, but since the gas cleaning device j controls the furnace top pressure, it finally opens fully.

In this way, gas cleaning equipment! controls the furnace top pressure, the bypass valve is fully open, and the turbine returns to its initial state of being stopped.

The switching method of the furnace top pressure control of the present invention and the method of the prior application (Special Publication Show! Otsu-♂θ? No. 2) enable the switching operation between the furnace top pressure control function of the p1 gas cleaning device and the turbine. This is done very smoothly and automatically by intervening the furnace top pressure control function of the bypass valve, and the reaction gas is removed using an expansion turbine under conditions where the cleaning function of the gas cleaning device is stably maintained. This has the excellent effect of being able to recover the energy retained in the system.

In addition, as a control example of the same system, Tokuko Sho-t3-32
There is θbu No. 6, but compared to the case where the gas cleaning device constantly controls the furnace top pressure and the turbine is operated continuously by controlling the turbine inlet pressure, the present invention reduces the differential pressure of the gas cleaning device. This has the advantage that even if the gas flow rate gain decreases, the turbine can be operated without deteriorating the controllability of the furnace top pressure control.

[Brief explanation of drawings]

The drawing is a layout diagram of the main parts of a blast furnace system to which an embodiment of the switching method of furnace top pressure control according to the present invention is applied. /06. Air blow m, λ10. Hot stove, 300. Blast furnace, Ri0
0. Dust catcher, j-,, gas cleaning equipment, Otsu 0
0. Turbine valve,? ,,,main blocking valve,? 68. Speed regulating valve, Wa00. Gas turbine, /θ000 generator, //
,,,turbine outlet valve, /2. ,, bypass valve, /
3.0. Furnace top pressure detector, /g00. Differential pressure detector, /ta 0
0. Turbine rotation speed detection device, /4. ,,on-off valve,A
16. Furnace top pressure setting device, B, B/F pass valve furnace top pressure control device, C, gas cleaning device furnace top pressure control device, D
,,,Pressure deviation setting device, g ,,,Furnace top pressure control changeover switch, ? ,,, differential pressure control device for gas cleaning equipment, G
, ,Low selector, H, ,Differential pressure setter, J. 91. Turbine governor, K, , valve opening limiter, L1
9. Load setting device, M,, Upper limit 1 degree setting device.

Claims (1)

[Scope of Claims] (1) A reaction gas cleaning device provided in the gas flow path for the reaction gas taken out from the reactor, an expansion turbine provided in the downstream gas flow path, and a device that bypasses the turbine. In a chemical reactor system equipped with a bypass valve provided in a gas flow path, each of which has a function of controlling the furnace top pressure of the reactor, the above control function of the reaction gas cleaning device and the control function of the bypass valve By creating a slight difference between the furnace top pressure setting values indicated by the furnace top pressure setting device for each, the furnace top pressure can be controlled while both of the above control functions are in operation. 9. A switching method for furnace top pressure control, characterized in that the responsibility for the function to be controlled is automatically switched from one to the other. 9) A reaction gas cleaning device installed in the gas flow path for the reaction gas taken out from the reactor, an expansion turbine installed in the downstream gas flow path, and a gas flow path that bypasses the turbine. In a chemical reactor system equipped with a bypass valve, each of which has a function of controlling the top pressure of the reactor, the above-mentioned control function of the reaction gas cleaning device and the control function of the bypass valve are respectively controlled. By creating a slight difference between the furnace top pressure set values indicated by the furnace top pressure setting device, the functions related to controlling the furnace top pressure can be controlled by the reactant gas while both of the above control functions are in operation. At the same time as switching from the cleaning device to a bypass valve, the reactive gas cleaning device is set in advance. A switching method for furnace top pressure control characterized by automatically switching to restriction based on an upper limit opening degree. (3) A reaction gas cleaning device installed in the gas flow path for the reaction gas taken out from the reactor, an expansion turbine installed in the downstream gas flow path, and a gas flow path that bypasses the turbine. In a chemical reactor system equipped with a bypass valve, each of which has a function of controlling the top pressure of the reactor, the control function of the reaction gas cleaning device and the control function of the bypass valve are respectively controlled. On the other hand, by creating a slight difference between the furnace top pressure set values indicated by the furnace top pressure setting device, the responsibility of the function related to the furnace top pressure control can be bypassed while leaving both of the above control functions in the operating state. A method for switching furnace top pressure control, characterized in that by switching from a valve to a reaction gas cleaning device, the reaction gas cleaning device automatically switches from constant differential pressure control and/or restriction by upper limit opening to furnace top pressure control.