JP2011163294A - Coal-gasified gas supply plant - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a convenient and practical coal-gasified gas supply plant for supplying a coal-gasified gas as a complementary fuel to a steam generation facility using a by-product gas which is secondarily generated from a steel maker as a main fuel and to a carburation blast-furnace gas-burning type gas turbine combined power generation facility using a carburation blast-furnace gas as a main fuel. <P>SOLUTION: After purifying the coal-gasified gas which is generated in a coal gasifying furnace 12 by a gas purifying device 14, the purified coal-gasified gas is introduced into an expansion turbine 16, and a generator 18 connected to the expansion turbine 16 generates power, and the power is used as a power source for the coal-gasified gas supply plant. The coal-gasified gas is subjected to adiabatic expansion by driving the expansion turbine 16, and the pressure and the temperature of the coal-gasified gas are lowered to the nearly same pressure and the temperature of the blast-furnace, and the coal-gasified gas is supplied as a complementary fuel to the carburation blast-furnace gas-burning type gas turbine combined power generation facility 5 and/or the steam power generation facility 3. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a steam power generation facility that uses as a by-product gas that is generated secondarily from a steel plant as a main fuel, and a reheated blast furnace gas that is a gas obtained by increasing the by-product gas to a predetermined calorific value as a main fuel. TECHNICAL FIELD The present invention relates to a coal gasification gas supply plant that supplies coal gasification gas as a supplementary fuel to an increased heat blast furnace gas-fired gas turbine combined power generation facility.

  Thermal power plants that are installed at steelworks and use by-product gas as the main fuel are important power sources such as safety power sources within the steelworks, so heavy oil that can continue power generation even when by-product gas decreases It consists of multiple steam power generation facilities with mixed-fired and exclusive-fired facilities, and a reheated blast furnace gas-fired gas turbine combined power generation facility that uses blast furnace gas as a fuel with coke oven gas and heat increased with mixed gas as a fuel. There are many more. The mixed gas is a gas in which two or three types of blast furnace gas, coke oven gas, and converter gas are mixed. In such a thermal power plant, the following problems occur with fluctuations and reductions in the amount of by-product gas and the amount of heat generated.

  The gas turbine combined power generation facility is operating to keep high output and high efficiency by pre-producing the by-product gas supplied from the steelworks, but because it cannot co-fire heavy fuel oil, etc. When the amount of coke oven gas and heat mix for heat decreases, the unit output decreases or the unit stops. In addition, when the calorific value of the blast furnace gas is reduced, or when the calorific value of the coke oven gas or mix gas, which is a high calorific value gas for increasing heat, is decreased, the amount of the heated blast furnace gas that has been increased to the predetermined calorific value is reduced. Decreases.

  On the other hand, steam power generation facilities generate power according to the amount of by-product gas supplied from the steelworks, so-called gas operation, so that stable operation and high-efficiency operation can be performed as the amount of by-product gas received varies. Can not. Also, expensive heavy oil is supplemented when the by-product gas is reduced due to blast furnace quiescence, etc., and the steel plant's safety power cannot be secured, or when the minimum output cannot be maintained. The auxiliary combustion of heavy oil is not environmentally preferable because sulfur oxides are generated.

  The above problem also applies to a thermal power plant having a power generation facility of either a gas turbine combined power generation facility or a steam power generation facility that uses by-product gas as a main fuel, and the present applicant solves such a problem. As a method, an invention in which LNG or gas hydrate is used as a supplementary fuel for by-product gas has been completed and patent applications have already been filed (for example, see Patent Document 1 and Patent Document 2).

  Also, in a combined power generation system using by-product gas as fuel, it is assumed that by-product gas fluctuations are large and cannot be operated efficiently, and coal is gasified in a gasification furnace, and methanol is synthesized from this gasification gas. There is also a combined power generation system using this methanol as a supplementary fuel for by-product gas (see, for example, Patent Document 3).

JP 2007-107401 A JP 2009-216334 A JP 2002-38971 A

  The technique described in Patent Document 3 is intended to cope with fluctuations in the by-product gas by once converting the gasification gas to methanol, but for producing, storing, and supplying methanol in addition to the gasification facility. Equipment is required. Further, in order to burn methanol, it is necessary to modify the gas turbine, and it is not easy in terms of cost and technology to apply to a thermal power plant equipped with an existing gas turbine power generation facility.

  The object of the present invention is to supplement steam power generation equipment mainly using by-product gas generated from steelworks as a main fuel, and reheat blast furnace gas-fired gas turbine combined power generation equipment mainly using reheat blast furnace gas. It is to provide a convenient and practical coal gasification gas supply plant that supplies coal gasification gas as fuel.

  The present invention relates to a steam power generation facility that uses as a by-product gas that is generated secondarily from a steel plant as a main fuel, and a reheated blast furnace gas that is a gas obtained by increasing the by-product gas to a predetermined calorific value as a main fuel. This is a coal gasification gas supply plant that supplies coal gasification gas as a supplementary fuel to a reheated blast furnace gas-fired gas turbine combined power generation facility, which purifies the coal gasification gas A gas refining device, an expansion turbine using high-temperature and high-pressure gas as a working fluid, and a coal gasification facility including a generator connected to the expansion turbine, and the high-temperature and high-pressure coal gasification gas purified by the gas refining device The expansion turbine is driven and power is generated by a generator connected to the expansion turbine. This is used as a power source for the plant, and the coal gasification gas after the expansion turbine is driven is used as the heat-up blast furnace gas. It is coal gasification gas supply plant and supplying as complementing fuel-fired gas turbine combined power generation facility and / or steam power generation facility.

  Further, in the present invention, in the coal gasification gas supply plant, the gasifying agent used for coal gasification is air, and the calorific value of the coal gasification gas is substantially the same as the calorific value of the reheat blast furnace gas. It is characterized by.

  The present invention further includes a small boiler using the coal gasification gas as a fuel, a steam turbine, and an air compressor connected to the steam turbine in the coal gasification gas supply plant, and steam generated by the small boiler is steamed. The high pressure air produced by the air compressor is used for coal gasification, which is sent to a turbine to drive an air compressor.

  Further, the present invention provides the coal gasification gas supply plant, wherein the coal gasification facility performs a holding operation when no coal gasification gas is supplied to the reheat blast furnace gas-fired gas turbine combined power generation facility and the steam power generation facility. Self-contained by driving the expansion turbine with the generated coal gasification gas, burning the coal gasification gas after driving the expansion turbine with the small boiler, and driving the air compressor with the generated steam It is characterized by being able to drive.

  A coal gasification gas supply plant according to the present invention drives an expansion turbine with a high-temperature and high-pressure coal gasification gas generated in a coal gasification furnace and purified by a gas purifier, and generates power with a generator connected to the expansion turbine. Since this is used as a power source for the plant, the power supplied to the plant from the outside can be reduced or stopped. The coal gasification gas after the expansion turbine is driven has its temperature and pressure lowered by adiabatic expansion, so it is supplied as supplementary fuel to the reheat blast furnace gas-fired gas turbine combined power generation facility and / or steam power generation facility. It is possible and efficient.

  Further, according to the present invention, the calorific value of the coal gasification gas is substantially the same as the calorific value of the reheat blast furnace gas, so that the reheat blast furnace gas-fired gas turbine combined power generation facility and / or steam power is hardly adjusted. It can be used as a supplementary fuel for power generation facilities and is very convenient.

  The present invention further includes a small boiler using coal gasification gas as a fuel, a steam turbine, and an air compressor connected to the steam turbine. The steam generated by the small boiler is sent to the steam turbine, and the air compressor is provided. It is practical because the high-pressure air that is driven and manufactured is used for coal gasification.

  Further, according to the present invention, the coal gasification gas supply plant according to the present invention can be maintained and operated in a self-contained manner, so that the coal gasification gas is added to the reheat blast furnace gas-fired gas turbine combined power generation facility and the steam power generation facility. It is not necessary to stop the plant even when no power is supplied, and it is possible to eliminate the start-up time and stop time and to avoid adverse effects on the plant due to the start-stop, and it can be said that the plant is easy to use and practical.

It is a process flow figure showing a schematic structure of coal gasification gas supply plant 1 as one embodiment of the present invention.

  FIG. 1 is a process flow diagram showing a schematic configuration of a coal gasification gas supply plant 1 as one embodiment of the present invention.

  The coal gasification gas supply plant 1 includes a steam power generation facility 3 that uses by-product gas that is secondarily generated from an ironworks as a main fuel, and a heat increase that is a gas obtained by increasing the by-product gas to a predetermined calorific value. It is a plant that supplies coal gasification gas as supplementary fuel to the blast furnace gas-fired gas turbine combined power generation facility 5 that uses blast furnace gas as the main fuel, coal gasification facility 10 that gasifies coal, and coal gasification Utility equipment 60 for producing high-pressure air or the like used for the construction is configured as a main equipment.

  The coal gasification facility 10 includes a coal gasification furnace 12 that gasifies coal, a pulverized coal machine 22 that produces pulverized coal used in the coal gasification furnace 12, and a pulverized coal supply that supplies pulverized coal to the coal gasification furnace 12. Apparatus 23, gas purification apparatus 14 for purifying coal gasification gas (generated gas) generated in the coal gasification furnace 12, expansion turbine using high-temperature and high-pressure coal gasification gas purified by the gas purification apparatus 14 as a working fluid 16, the generator 18 connected with the expansion turbine 16, and the coal gasification equipment control apparatus 20 which controls operation | movement of the coal gasification furnace 12, etc. are included.

  The coal gasification furnace 12 is an air-blown coal gasification furnace, which houses a gasification furnace (not shown) in a pressure vessel (not shown), and is a pulverized coal and a gasifying agent in the gasification furnace. Reacts with air to produce flammable gases including hydrogen, carbon monoxide, and methane. Coal is made into pulverized coal by the pulverized coal machine 22, and then air-carryed with nitrogen gas to the gasifier through the pulverized coal supply device 23. On the other hand, air as a gasifying agent is sent from an axial flow type air compressor 66. The gasification furnace has a temperature of about 1200 to 1800 ° C. and a pressure of about 2.0 to 2.5 MPa, and a high-temperature and high-pressure product gas can be obtained. This high-temperature and high-pressure product gas is cooled by a gasifier cooler 24 provided at the outlet of the gasifier, and then sent to the gas purifier 14.

  The gas purification device 14 is a device for removing impurities in the product gas, and includes a dedusting device 26 and a desulfurization device 28. The dedusting device 26 is provided on the downstream side of the gasifier cooler 24, and separates and collects the char discharged from the coal gasifier 12 along with the generated gas. The dedusting device 26 is exemplified by a cyclone or a filter. The recovered char is returned to the gasifier through the return line 30 and the unburned portion is gasified in the gasifier. The product gas after dedusting is sent to the desulfurization device 28 where sulfur compounds contained in the product gas are removed. The desulfurization device 28 is a dry desulfurization device, and examples of the desulfurization agent include iron oxides.

  The product gas purified by the gas purifier 14 has a temperature of about 400 to 500 ° C. and a pressure of about 2.0 to 2.5 MPa, and is sent to the expansion turbine 16 to drive the expansion turbine 16. The expansion turbine 16 is connected to a generator 18 and is generated by driving the expansion turbine 16. The electric power generated here is used as a power source of this plant including the coal gasification facility 10 such as the power of the pulverized coal machine 22. In the case of an air-blown coal gasifier, it is not necessary to produce oxygen because the gasifying agent is air. However, as with the oxygen-blown coal gasifier, nitrogen gas that purges pulverized coal to the gasifier, and for purging Nitrogen gas is necessary, and an air separation device for producing nitrogen gas is generally installed. In the case of an air-blown coal gasifier, the air separation device can be downsized compared to an oxygen-blown coal gasifier, so less power is used, and power from the outside can be obtained by using the power generated by the generator 18. Can be significantly reduced or stopped. In addition, there is a lot of nitrogen gas in the steelworks to produce oxygen used in the converter. If you can receive the nitrogen gas used in this plant, including high-pressure nitrogen gas for air current transportation from the steelworks, you can install an emergency micro air separation device, and nitrogen gas will be supplied reliably. In this case, an air separation device need not be installed. The product gas that has driven the expansion turbine 16 here adiabatically expands to lower the temperature to 50 to 80 ° C. and the pressure to a level slightly higher than the blast furnace gas.

  A generated gas supply line 40 for supplying the generated gas to the steam power generation facility 3 and / or the reheat blast furnace gas-fired gas turbine combined power generation facility 5 is connected to the outlet of the expansion turbine 16 to drive the expansion turbine 16. The generated gas is sent to the steam power generation facility 3 and / or the blast furnace gas-fired gas turbine combined power generation facility 5 through the generated gas supply line 40. The product gas supply line 40 is provided with a branch line 46 for supplying the product gas to the small boiler 62. Furthermore, a pressure control line 48 for controlling the pressure of the product gas supply system is connected to the branch line 46. A pressure detector 50 is attached to the branch line 46. When the pressure in the branch line 46 exceeds a predetermined pressure, the pressure regulator 52 opens the system pressure control valve 54 interposed in the pressure control line 48, The product gas is guided to the flare stack 56 and the pressure of the product gas supply system is reduced. The product gas supply line 40 is connected to an expansion turbine bypass line 44 that bypasses the expansion turbine 16 and is provided with a bypass valve 42. Even if a problem occurs in the expansion turbine 16, the expansion turbine bypass line is connected. The product gas can be supplied via 44.

  The utility facility 60 is a facility for producing high-pressure air mainly used in the coal gasification facility 10, and is connected to the small boiler 62, the steam turbine 64 driven by the steam generated by the small boiler 62, and the steam turbine 64. An axial flow type air compressor 66, a condenser 68, and a generator motor 80 are configured as main devices. Here, since all the nitrogen gas used in this plant including nitrogen gas for airflow conveyance is supplied from the steelworks, no air separation device for producing nitrogen gas is installed. When installing an air separation device for producing nitrogen gas, the high pressure air produced by the air compressor 66 may be led to the air separation device to produce nitrogen gas by a known method.

  The small boiler 62 uses the produced gas supplied through the branch line 46 in which the small boiler fuel flow control valve 70 and the shutoff valve 72 are interposed as fuel, and sends the generated steam to the steam turbine 64 through the steam line 74. 64 is driven. The small boiler 62 basically has only to be capable of producing predetermined air by the air compressor 66 connected to the steam turbine 64, and the steam turbine 64 having the ability to generate steam for sending factory air to the steelworks.

  The steam turbine 64 is driven by steam sent from a steam line 74 in which a steam stop valve 76 and a steam control valve 78 are interposed, and a connected air compressor 66 produces high-pressure air. The produced high-pressure air is sent to the coal gasification furnace 12 as a gasifying agent. A generator motor 80 is connected to the air compressor 66, and high-pressure air necessary for starting the coal gasification facility 10 is driven by using the generator motor 80 as a drive motor to drive the air compressor 66. To manufacture. An expansion turbine 81 driven by high-pressure air produced by the air compressor 66 is connected to the generator motor 80. Even if the load of the coal gasification furnace 12 is reduced and the required amount of air is reduced, the high-pressure air produced by the axial flow type air compressor 66 for preventing surging cannot be reduced below a predetermined amount. Air is sent to the expansion turbine 81 by the surplus air control valve 100 to drive the expansion turbine 81. The expansion turbine 81 is connected to a generator motor 80, and power is generated when the expansion turbine 81 is driven. The generated power is used as a power source for the plant. The air whose pressure has been reduced by the expansion turbine 81 is sent from the forced air blower 90 to the combustion air line 91 that sends the combustion air to the small boiler 62 and is used as the combustion air. By using the air whose pressure is reduced in the expansion turbine 81, the number of operating units of the forced draft fan 90 is reduced, and the power is reduced by restricting the combustion air flow rate control vane 92. The generator motor 80 can also be a generator by introducing start-up steam from the steam generator boiler 130 to the steam turbine 64.

  The steam exhausted from the steam turbine 64 is cooled by the condenser 68 to become condensate, and is then sent as cooling water to the gasifier cooler 24 by the feed water pump 82, where it is discharged from the gasifier. After exchanging heat with the product gas and being heated, it is sent to the small boiler 62 as feed water. Thus, thermal efficiency can be improved by utilizing the gasifier cooler 24 as a feed water heater. Moreover, thermal efficiency can also be improved by supplying steam turbine bleed air as factory air supply for steelworks.

Heated blast furnace gas-fired gas turbine combined power generation facility 5 is a coal gasification of a blast furnace gas or a blast furnace gas obtained by mixing a coke oven gas and a mixed gas as heat increasing gas with a blast furnace gas sent from an ironworks. This is a power generation facility that uses gas mixed with fuel as fuel. The fuel compressor 102 pressurizes the heated blast furnace gas, etc., mixes it with high-pressure air sent from the air compressor 104, burns it, and sends it out from the combustor 106. The gas turbine 108 is driven by the combustion gas. The gas turbine 108 is connected to and drives the generator 110, the fuel compressor 102, and the air compressor 104. The combustion gas that has driven the gas turbine 108 is sent to an exhaust heat recovery boiler (not shown), recovers heat by the exhaust heat recovery boiler, and drives a generator 110 connected via a steam turbine (not shown). Generate electricity. The heat-up blast furnace gas has a calorific value of about 4200 kJ / m ³ N. Mixing gas into the mixer 122 interposed in the blast furnace gas line 120 for supplying the blast furnace gas, and coke oven gas into the mixer 123 are mixed. can get. Further, the blast furnace gas line 120 is provided with a mixer 124 for mixing coal gasification gas upstream of the mixer 123, and downstream of the mixer 122 such as soot and dust contained in blast furnace gas. An electrostatic precipitator 126 is provided for removing impurities.

  The steam power generation facility 3 is a reheated blast furnace gas obtained by mixing a blast furnace gas supplied from an ironworks with a mixed gas that is a heat increasing gas, or a coal gasification gas sent from the coal gasification facility 10 and a flame holding fuel. A plurality of steam power generation boilers 130 using coke oven gas and heavy oil as fuels are provided, and each fuel is sent to the steam power generation boiler 130 through a blast furnace gas line 132, a coke oven gas line 134, and a heavy oil line 136. The blast furnace gas line 132 is provided with a mixer 138 for mixing the coal gasification gas from the upstream side toward the downstream side, and a mixer 142 for mixing the mixed gas. The steam generated in the steam generator boiler 130 is sent to a steam turbine (not shown) and is generated by a generator (not shown) connected to the steam turbine.

  The generated gas supply line 40 drives the expansion turbine 16 and supplies the generated gas having a temperature of 50 to 80 ° C. and a pressure slightly higher than that of the blast furnace gas to the steam power generation facility 3 and / or the reheated blast furnace gas-fired gas turbine combined power generation facility 5. One end of the expansion turbine 16 and the other end branched into two. One product gas supply line 40a was interposed in a blast furnace gas line 120 for sending blast furnace gas to the fuel compressor 102. The other product gas supply line 40 b is connected to the mixer 124 and is connected to a mixer 138 interposed in a blast furnace gas line 132 that sends blast furnace gas to the boiler 130 for steam power generation. The two product gas supply lines 40a and 40b include mixed flow rate control valves 41a and 41b, respectively.

Next, an example of the operating procedure of the coal gasification gas supply plant 1 is shown.
The master control device 7 performs overall operation control including the coal gasification gas supply plant 1, the steam power generation facility 3, and the reheat blast furnace gas-fired gas turbine combined power generation facility 5. The master control device 7 sends a blast furnace gas, coke oven gas, or mixed gas from the steelworks in response to a signal from a control device (not shown) that controls the steam power generation facility 3 and the heated blast furnace gas-fired gas turbine combined power generation facility 5 respectively. If it is determined that supply of the generated gas is unnecessary, a standby command is issued to the coal gasification equipment control device 20. The regenerative blast furnace gas-fired gas turbine combined power generation facility 5 and / or the steam power generation facility 3 generates power using the blast furnace gas, coke oven gas, or mixed gas from the steelworks as fuel as in the conventional case.

  The coal gasification facility 10 in the standby state minimizes the load of the coal gasification furnace 12, drives the generator 18 through the expansion turbine 16, generates power, and uses the generated gas after passing through the expansion turbine 16 as a utility facility 60. And continue operation in a self-contained manner. As for the amount of generated gas used in the utility facility 60 in the standby state, the axial air compressor 66 produces high pressure air exceeding the necessary amount by preventing surging, and supplies steam turbine bleed air as factory air supply for steelworks. The amount and the amount of produced gas at the minimum load of the coal gasifier 12 are balanced to be almost the same. This balance is also such that the generated gas pressure in the branch line 46 rises or falls due to slight fluctuations in the amount of generated gas generated, fluctuations in seawater temperature, fluctuations in the factory air supply amount, etc. The control device 20 increases the generated gas in the coal gasifier 12 when the generated gas pressure is reduced, and the high pressure air produced by the air compressor 66 before the system pressure control valve 54 is opened if the generated gas pressure in the branch line 46 increases. To increase the amount of generated gas supplied to the small boiler 62 so that the system pressure control valve 54 is not operated as much as possible. High-pressure air that is not used in the coal gasification furnace 12 is sent to the expansion turbine 81, drives the expansion turbine 81, and is generated by the connected generator motor 80 to be recovered as electric power. The electric power obtained by the generator 18 by driving the expansion turbine 16 serving as the power source of the plant decreases when the coal gasification furnace 12 is operated at the minimum load, but is expanded by the high-pressure air sent to the expansion turbine 81. Since the electric power obtained by driving the turbine 81 and the connected generator motor 80 is increased, the electric power from the outside can be suppressed even in the standby state. Further, since the exhaust gas from the expansion turbine 81 is used as combustion air for the small boiler 62, the power is reduced by reducing the number of operation of the forced draft fan 90. If this plant is completely shut down, it takes time for re-startup, and the coal gasifier 12 is thermally affected by temperature changes. However, such a problem occurs when the coal gasifier 12 is continuously operated at the minimum load. Can be avoided.

  The master control device 7 is a blast furnace gas or coke oven that is sent from the ironworks by signals from a control device (not shown) that controls the steam power generation facility 3 and the reheat blast furnace gas-fired gas turbine combined power generation facility 5 respectively. When it is determined that the supply of the generated gas is effective due to a shortage of gas or mixed gas, a supply command is issued to the coal gasification equipment control device 20. Receiving the supply command, the coal gasification equipment control device 20 increases the pulverized coal of the coal gasification equipment 10 and opens the steam control valve 78 to increase the high-pressure air as the gasifying agent. When the opening of the steam control valve 78 increases, the steam pressure for driving the steam turbine 64 decreases, so that the small boiler fuel flow control valve 70 and the combustion air flow control vane 92 are opened in cooperation with the surplus air control valve 100. To control. A predetermined amount of generated gas is generated and supplied to the blast furnace gas lines 120 and 132 through the generated gas supply line 40. At this time, the master control device 7 controls the mixed flow rate control valves 41a and / or 41b so as to send the generated gas preferentially to the regenerative blast furnace gas-fired gas turbine combined power generation facility 5 with high power generation efficiency.

  The generated gas to be sent to the increased heat blast furnace gas-fired gas turbine combined power generation facility 5 is lowered to a temperature of about the blast furnace gas by the gas cooler 43, mixed with the blast furnace gas by the mixer 124, and then sent to the fuel compressor 102. The gas cooler 43 is a direct cooling type heat exchanger, and cools the return gas of the fuel compressor 102 and returns it to the inlet of the fuel compressor 102, more specifically, to the downstream side of the electric dust collector 126. The cooling water of the gas cooler (not shown) is shared. The amount of return gas of the fuel compressor 102 that passes through the direct-cooling gas cooler (not shown) is small when the output of the high-temperature blast furnace gas-fired gas turbine combined power generation facility 5 is high, and the return gas that circulates increases when the output decreases. Therefore, if a high output is maintained by supplying the generated gas, the amount of cooling water in the direct cooling gas cooler (not shown) is sufficient even if the cooling water is shared. The gas cooler 43 is for suppressing the reduction of the compression efficiency of the fuel compressor 102. Even if the cooling water temporarily runs short, for example, when the high-temperature blast furnace gas-fired gas turbine combined power generation facility 5 is tripped. It is not a big problem.

  The temperature of the blast furnace gas sent from the steelworks fluctuates in proportion to the atmospheric temperature, and is about 15 ° C. in winter and about 40 ° C. in summer. On the other hand, the generated gas temperature after driving the expansion turbine 16 is 50 to 80 ° C., which is slightly higher than the blast furnace gas temperature. As the inlet gas temperature of the fuel compressor 102 increases, the gas density decreases and the power of the fuel compressor 102 increases. For this reason, in this embodiment, the gas cooler 43 is provided and the generated gas temperature is lowered to about the blast furnace gas temperature. As described above, it is preferable to provide the gas cooler 43 and lower the generated gas temperature to about the blast furnace gas temperature and supply it to the blast furnace gas line 120. Even if it does, since the rise of the inlet gas temperature of the fuel compressor 102 is slight, the gas cooler 43 is not necessarily required. On the other hand, it is better not to cool the generated gas in the boiler 130 for steam power generation because the boiler efficiency increases when the fuel gas is heated. For this reason, the gas cooler is not provided in the product gas supply line 40b which sends the product gas to the steam power generation facility 3.

Similarly, the produced gas sent to the steam power generation facility 3 is mixed with the blast furnace gas by the mixer 138 and then sent to the boiler 130 for steam power generation. A blast furnace gas line 132 downstream of the mixer 138 is provided with a mixer 142 that mixes a specified amount of mix gas from an ironworks. The amount of heat generated from the blast furnace gas must be within the range of the amount of heat generated by the blast furnace gas burner, so that the generated gas and the mixed gas must be mixed. A quantity detector 135 is provided, and the calorific value adjuster 139 adjusts the mixed flow rate control valve 41b so that the heat generation blast furnace gas calorific value does not exceed a predetermined calorific value. The mixed flow rate control valve 41 b is provided with a low signal selector 144 that selects the lower one of the adjustment signal from the master control device 7 and the adjustment signal from the calorific value detector 135. Since the mixed gas flow rate control valve 146 needs to consume a specified amount of mixed gas from the steelworks, the flow rate / heat value controller 148 adjusts the heat value to be slightly higher than the heat value controller 139. Since the coal gas furnace 12 is an air-blown gasification furnace, the generated gas has a calorific value of about 4200 kJ / m ³ N, the blast furnace gas is about 3400 kJ / m ³ N, and the mixed gas is about 11000 kJ / m ³ N. Since the upper limit calorific value of the heat increasing blast furnace gas is 5000 kJ / m ³ N, the final calorific value adjustment is preferably performed with a mixed gas.

  In a state where the generated gas is sent from the coal gasification facility 10 to the reheat blast furnace gas-fired gas turbine combined power generation facility 5 and / or the steam power generation facility 3, the blast furnace gas, coke oven gas, or mixed gas sent from the ironworks is When it is determined that the supply of the generated gas is unnecessary, the master controller 7 issues a command to the coal gasification facility controller 20 to reduce the load. Further, if the pressure detected by the pressure detector 50 of the generated gas supply system rises, the coal gasification equipment control device 20 performs adjustment to lower the load of the coal gasification equipment 10 and raise the load if the pressure decreases. When the pressure is exceeded, the pressure regulator 52 controls to open the system pressure control valve 54 to release a part of the generated gas to the flare stack 56 and maintain the pressure of the generated gas supply system at a predetermined pressure.

  In the above embodiment, the coal gasification facility 10 is operated to supply the generated gas so that the output of the reheat blast furnace gas-fired gas turbine combined power generation facility 5 and / or the steam power generation facility 3 can be maintained at a high output. However, it is also possible to operate the coal gasification facility 10 at a constant load, and operate the heat-increasing blast furnace gas-fired gas turbine combined power generation facility 5 and / or the steam power generation facility 3 accordingly. Furthermore, it is also possible to operate while changing the load of each facility so that the operation of the reheated blast furnace gas-fired gas turbine combined power generation facility 5, the steam power generation facility 3 and the coal gasification facility 10 as a whole becomes easy. As described above, the coal gasification gas supply plant 1 is capable of flexibly responding to fluctuations in the gas amount and heat generation amount of by-product gas that is secondarily generated from the steelworks, and is a practical plant. I can say that.

Moreover, in the said embodiment, although the example of the air blowing coal gasification furnace which uses air for a gasifying agent was shown, oxygen-enriched air which mixed oxygen or oxygen and air can also be used for a gasifying agent. . When oxygen or oxygen-enriched air is used as the gasifying agent, the generated gas has a higher calorific value than when gas is used as the gasifying agent, and when oxygen is used as the gasifying agent, the calorific value is 10,000 to 11,000 kJ / m. because it is ^{3 N,} it may be used as increasing thermal gas. Moreover, the coal gasification equipment which can be used by this invention should just be able to manufacture the product gas which has a calorific value equivalent to or more than the reheat blast furnace gas, and the kind of coal gasification furnace is not specifically limited. Moreover, the shift gas reactor which converts a carbon monoxide into a carbon dioxide in the downstream of a gas refiner | purifier, Furthermore, the coal gasification equipment provided with the carbon dioxide removal apparatus in the downstream may be sufficient.

DESCRIPTION OF SYMBOLS 1 Coal gasification gas supply plant 3 Steam power generation equipment 5 Heat increase blast furnace gas-fired gas turbine combined power generation equipment 10 Coal gasification equipment 12 Coal gasification furnace 14 Gas refiner 16 Expansion turbine 18 Generator 40 Generated gas supply lines 40a and 40b Generated gas supply line 60 Utility equipment 62 Small boiler 64 Steam turbine 66 Air compressor 102 Fuel compressor 104 Air compressor 106 Combustor 108 Gas turbine 110 Generator 120 Blast furnace gas line 124 Mixer 130 Steam generator boiler 132 Blast furnace gas line 134 Coke Oven Gas Line 136 Heavy Oil Line 138 Mixer

Claims (4)

Steam power generation facility that uses by-product gas that is generated secondaryly from steelworks as a main fuel, and reheat blast furnace that uses heat-increased blast furnace gas that is a gas obtained by heating the by-product gas to a predetermined calorific value A coal gasification gas supply plant that supplies coal gasification gas as a supplementary fuel to a gas-fired gas turbine combined power generation facility,
A coal gasification furnace for gasifying coal, a gas purifier for purifying coal gasification gas, an expansion turbine using high-temperature and high-pressure gas as a working fluid, and a coal gasification facility including a generator connected to the expansion turbine,
Driving the expansion turbine with high-temperature and high-pressure coal gasification gas purified by the gas purification device, generating electricity with a generator connected to the expansion turbine, and using this as a power source for the plant,
A coal gasification gas supply plant that supplies the coal gasification gas after driving the expansion turbine as a supplementary fuel to the reheat blast furnace gas-fired gas turbine combined power generation facility and / or steam power generation facility.   2. The coal gasification gas according to claim 1, wherein the gasification agent used for coal gasification is air, and the calorific value of the coal gasification gas is substantially the same as the calorific value of the reheat blast furnace gas. Supply plant. In addition, it includes a small boiler powered by coal gasification gas, a steam turbine and an air compressor connected to the steam turbine,
The coal gas according to claim 2, wherein steam generated by the small boiler is sent to a steam turbine, an air compressor is driven, and high-pressure air produced by the air compressor is used for coal gasification. Gasification plant.   The coal gasification facility performs a holding operation when no coal gasification gas is supplied to the reheat blast furnace gas-fired gas turbine combined power generation facility and steam power generation facility, and drives the expansion turbine with the generated coal gasification gas. The self-contained operation can be achieved by burning the coal gasification gas after driving the expansion turbine with the small boiler and driving the air compressor with the generated steam. The coal gasification gas supply plant described.

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