Gasification efficiency adjusting system of gasification furnace and working method thereof
Technical Field
The invention belongs to the technical field of gasification furnaces, and particularly relates to a gasification efficiency adjusting system of a gasification furnace and a working method thereof.
Background
The coal gasification technology is a core technology for clean and efficient utilization of coal, is a key technology for developing advanced clean coal power generation, coal chemical industry, coal-based poly-generation and other energy systems, and has important influence on the operation reliability and economy of each system. Driven by the rapid development of modern coal chemical engineering projects, coal gasification technology is developing towards large-scale, clean, efficient and wide coal adaptability. The development of coal gasification technology presents a lot of flowers, but in the development process of the high-efficiency clean coal gasification technology at the present stage, a plurality of problems still exist and need to be solved.
The gasification efficiency of the gasification furnace is an important index for measuring the working performance of the gasification furnace, but the adjustment and control of the gasification efficiency of the gasification furnace is always one of the world problems in the field of coal gasification.
Disclosure of Invention
In order to solve the above problems, an object of the present invention is to provide a gasification efficiency adjusting system of a gasification furnace and a working method thereof, which can effectively improve gasification efficiency of the gasification furnace and ensure efficient and stable operation of the gasification furnace.
The invention is realized by the following technical scheme:
the invention discloses a gasification efficiency regulating system of a gasification furnace, which comprises an efficiency regulating device, an initial working condition controller, a water vapor flow detection and control device, an oxygen flow detection and control device, a fly ash carbon residue on-line detection device and a CO (carbon monoxide) on-line detection device2An online detection device;
the water vapor flow detection and control device is connected with the water vapor system of the gasifier nozzle, and the oxygen flow detection and control device is connected with the oxygen system of the gasifier nozzleThe initial working condition controller is respectively connected with a pulverized coal system, a water vapor system and an oxygen system of a burner of the gasification furnace, the fly ash carbon residue on-line detection device and the CO2The online detection device is arranged at the waste boiler outlet of the gasification furnace; water vapor flow detection and control device, oxygen flow detection and control device, fly ash residual carbon online detection device and CO2The on-line detection device is respectively connected with the efficiency adjusting device.
Preferably, the efficiency-adjusting device is a DCS.
Preferably, the initial condition controller is a PLC.
Preferably, the steam flow detecting and controlling device comprises a steam flow meter and a steam regulating valve, and the steam flow meter and the steam regulating valve are arranged on a steam pipeline connected with the gasifier burner and are respectively connected with the efficiency regulating device.
Preferably, the oxygen flow detection and control device comprises an oxygen flow meter and an oxygen regulating valve, and the oxygen flow meter and the oxygen regulating valve are arranged on an oxygen pipeline connected with the gasifier burner and are respectively connected with the efficiency regulating device.
Preferably, CO2The on-line detection device comprises a synthetic gas flowmeter and CO2An analyzer.
The working method of the gasification efficiency regulating system of the gasification furnace disclosed by the invention comprises the following steps:
setting an initial working condition of the gasification furnace through an initial working condition controller, and feeding coal powder, water vapor and oxygen, wherein the initial working condition enables the gasification furnace to reach the optimal slag temperature on one hand and enables the gasification furnace to reach the reaction condition temperature of carbon and water reaction on the other hand; after the initial working condition is stable, starting the efficiency adjusting device to enable the gasifier to reach 100% of rated working condition; the efficiency regulating device detects the carbon content and CO in the fly ash according to the coal powder amount and the fly ash carbon residue on-line detection device2CO in synthesis gas detected by on-line detection device2Content, calculating corresponding oxygen amount and water vapor amount, and controlling oxygen amount and water vapor amount entering into the gasification furnace by the water vapor flow detection and control device and the oxygen flow detection and control device to make coal and O2Reaction exotherm equal to C andthe water vapor reaction absorbs heat, so that the gasifier achieves heat and temperature balance, and the gasification efficiency of the gasifier is improved.
Preferably, controlling the amount of oxygen and the amount of water vapor entering the gasifier is performed by the following formula:
Z1×M1×(Xc-X'-XCO2)/12=2M2+M3
Z2×M2×222=λ×Z3×M3×131
wherein M is1For the amount of coal charged, M2Amount of oxygen, M3Is H2O content, Xc is the carbon content of coal powder dry base, X' is the carbon content of fly ash, XCO2For CO in synthesis gas2Content of, Z1、Z2And Z3In order to take into account the correction coefficient of the side reaction in the gasification furnace, λ is a correction coefficient taking into account the heat loss.
Further preferably, Z1、Z2And Z3The value ranges of (1) and (2) are all 0.5-1.5; the value range of lambda is 0.8-1.2.
Preferably, the initial working condition is 40-80% of the rated working condition, and the optimal slag temperature is 150 ℃ higher than the ash melting point.
Compared with the prior art, the invention has the following beneficial technical effects:
the invention discloses a gasification efficiency regulating system of a gasification furnace, which firstly controls the initial working condition of the gasification furnace through an initial working condition controller, and controls the feeding amount of coal, water vapor and oxygen according to simulation and experience, so that the gasification furnace reaches the optimal slag temperature on one hand, and the gasification furnace reaches the reaction condition temperature of carbon and water reaction on the other hand. Then the coal and O are mixed by an efficiency regulating device2The exothermic heat of reaction is equal to the endothermic heat of reaction between C and water vapor, so that the gasifier reaches the heat and temperature balance. On one hand, the design can effectively control the heat balance of the gasification furnace, control the gasification temperature and reduce the chilling gas quantity; on one hand, the gasification furnaces CO and H can be controlled by adjusting2The proportion of (2) can effectively improve the gasification efficiency of the gasification furnace and ensure the efficient and stable operation of the gasification furnace.
Furthermore, the efficiency adjusting device adopts DCS, so that the calculation precision is high, and the safety and the stability are strong.
Furthermore, the initial working condition controller adopts a PLC, is flexible to construct and can meet the control requirement of the initial working condition.
The working method of the gasification efficiency regulating system of the gasification furnace disclosed by the invention has high automation degree, can effectively control the heat balance of the gasification furnace, control the gasification temperature, reduce the amount of chilling gas, and control the CO and H of the gasification furnace through regulation2The proportion of (2) can effectively improve the gasification efficiency of the gasification furnace and ensure the efficient and stable operation of the gasification furnace.
Furthermore, the oxygen and water vapor amount can be accurately controlled through a formula, and the efficiency of the gasification furnace is further improved.
Furthermore, according to the real-time working conditions of the raw materials and the gasification furnace, the Z and the lambda are adopted to correct the side reaction and the heat loss, so that the accuracy of controlling the amount of the chilling gas can be further improved.
Drawings
Fig. 1 is a schematic view of the overall structure of a gasification efficiency adjustment system of a gasification furnace according to the present invention.
In the figure: 1-efficiency adjusting device, 2-initial working condition controller, 3-steam flow detection and control device, 4-oxygen flow detection and control device, 5-fly ash carbon residue on-line detection device, 6-CO2And (4) an online detection device.
Detailed Description
The present invention will now be described in further detail with reference to the accompanying drawings, which are included to illustrate and not to limit the invention:
referring to fig. 1, the gasification efficiency adjusting system of the gasification furnace of the present invention comprises an efficiency adjusting device 1, an initial condition controller 2, a steam flow detecting and controlling device 3, an oxygen flow detecting and controlling device 4, a fly ash carbon residue on-line detecting device 5 and CO2An on-line detection device 6;
the steam flow detection and control device 3 is connected with a steam system of the gasifier burner, the oxygen flow detection and control device 4 is connected with an oxygen system of the gasifier burner, and the initial working condition is controlledThe device 2 is respectively connected with a pulverized coal system, a water vapor system and an oxygen system of a gasifier burner, a fly ash carbon residue on-line detection device 5 and CO2The online detection device 6 is arranged at the waste boiler outlet of the gasification furnace; a steam flow detection and control device 3, an oxygen flow detection and control device 4, a fly ash carbon residue on-line detection device 5 and CO2The online detection devices 6 are respectively connected with the efficiency adjusting device 1.
When the system is constructed, the efficiency adjusting device 1 can adopt DCS, and the initial working condition controller 2 can adopt PLC.
The steam flow detection and control device 3 comprises a steam flow meter and a steam regulating valve, and the steam flow meter and the steam regulating valve are arranged on a steam pipeline connected with the gasifier burner and are respectively connected with the efficiency regulating device 1. The oxygen flow detection and control device 4 comprises an oxygen flow meter and an oxygen regulating valve, and the oxygen flow meter and the oxygen regulating valve are arranged on an oxygen pipeline connected with the gasifier burner and are respectively connected with the efficiency regulating device 1.
CO2The on-line detection device 6 comprises a synthesis gas flowmeter and CO2An analyzer.
The working method of the gasification efficiency regulating system of the gasification furnace comprises the following steps:
setting an initial working condition of the gasification furnace through the initial working condition controller 2, wherein the initial working condition is 40-80% of a rated working condition, and feeding coal powder, water vapor and oxygen, and the initial working condition enables the gasification furnace to reach an optimal slag temperature on one hand, the optimal slag temperature is 150 ℃ higher than an ash melting point, and enables the gasification furnace to reach a reaction condition temperature of carbon and water reaction on the other hand; after the initial working condition is stable, starting the efficiency adjusting device 1 to enable the gasification furnace to reach 100% of rated working condition; the efficiency adjusting device 1 detects the carbon content and CO in the fly ash according to the coal powder amount and the fly ash carbon residue on-line detection device 52CO in the synthesis gas detected by the on-line detection device 62Content, calculating corresponding oxygen amount and water vapor amount, and controlling oxygen amount and water vapor amount entering into the gasification furnace by the water vapor flow detection and control device 3 and the oxygen flow detection and control device 4 to make coal and O2The exothermic heat of reaction is equal to the endothermic heat of reaction of C and water vapor,thereby the gasifier reaches the heat and temperature balance, and the gasification efficiency of the gasifier is improved.
Controlling the amount of oxygen and the amount of water vapor entering the gasifier is performed by the following formula:
Z1×M1×(Xc-X'-XCO2)/12=2M2+M3
Z2×M2×222=λ×Z3×M3×131
wherein M is1For the amount of coal charged, M2Amount of oxygen, M3Is H2O content, Xc is the carbon content of coal powder dry base, X' is the carbon content of fly ash, XCO2For CO in synthesis gas2Content of, Z1、Z2And Z3In order to take account of the correction factor for the side reactions in the gasifier, in general, Z1、Z2And Z3The value ranges of (1) and (2) are all 0.5-1.5; λ is a correction coefficient considering heat loss, and generally, the value range of λ is 0.8-1.2.
The invention is further explained below in a specific embodiment:
2000t/d dry pulverized coal pressurized gasifier, the carbon content of the coal as fired is 69%, the residual carbon of fly ash is 2%, and CO2The conversion rate is 6.6%, the coal as fired contains 2% of water, and the coal as fired contains 4.5% of hydrogen.
Initial working condition: 4 burners, each burner is added with 9907kg/h of coal powder; 8028kg/h of oxygen is added into each burner; adding steam into each burner at 900 kg/h; the gasification temperature reached 1500 ℃. The amounts of carbon monoxide and hydrogen in the synthesis gas are: CO, 593 kmol/h; h2205.3kmol/h, molar ratio: CO: H22.9: 1, the effective gas amount is 798.1 kmol/h.
After the gasification efficiency adjusting system of the gasification furnace is started, the remaining 50% coal dust using efficiency adjusting device 1 is used for proportioning oxygen and water vapor, each burner is added with 9907kg/h of coal dust, 4313.6kg/h of oxygen and 4111.2kg/h of water vapor, the proportioning ensures that the temperature of the gasification furnace is still 1500 ℃ under 100% working condition, the effective gas amount is increased by 898.4kmol/h, and the amounts of carbon monoxide and hydrogen in synthesis gas are respectively as follows: CO, 498 kmol/h; h2400.4kmol/h, molar ratio: CO: H2=1.24:1。
Then 100% of the operating conditions, the syngas production is 1696.5kmol/h, and the molar ratio of carbon monoxide to hydrogen is: CO: H21.8: 1, H in syngas2The amount of the compound is greatly improved.
The main reactions in the system are as follows:
1. steam reforming reaction
C+H2O=CO+H2-131KJ/mol
2. Water gas shift reaction
CO+H2O=CO2+H2+42KJ/mol
3. Partial oxidation reaction
C+0.5O2=CO+111KJ/mol
4. Complete oxidation (combustion) reaction
C+O2=CO2+394KJ/mol
5. Methanation reaction
CO+2H2=CH4+74KJ/mol
Boudouard reaction
C+CO2=2CO+-172KJ/mol
The above description is only a part of the embodiments of the present invention, and although some terms are used in the present invention, the possibility of using other terms is not excluded. These terms are used merely for convenience in describing and explaining the nature of the invention and are to be construed as any additional limitation which is not in accordance with the spirit of the invention. The foregoing is merely an illustration of the present invention for the purpose of providing an easy understanding and is not intended to limit the present invention to the particular embodiments disclosed herein, and any technical extensions or innovations made herein are protected by the present invention.