Improved Lurgi gasification furnace waste heat recovering method and device

Abstract

The invention belongs to the technical field of energy recovery and relates to a method for secondary recovery of waste heat of a Lurgi gasification furnace and a device for realizing the method. The waste heat recovery is realized by adopting two stages of waste heat boilers. The method comprises the following steps: raw gas discharged from the gasification process of coal is firstly subjected to spray cooling by utilizing diluted phenol water from a diluted phenol water tank in a primary spray cooler, the cooled raw gas enters to a primary waste heat boiler, and in the primary waste heat boiler, steam is generated by boiler feedwater in the heating shell pass of the raw gas; raw gas discharged from the primary waste heat boiler is subjected to spray cooling by utilizing diluted phenol water in a secondary spray cooler, the cooled raw gas enters into a secondary waste heat boiler, and in the secondary waste heat boiler, steam is generated by boiler feedwater in the heating shell passof the raw gas. The device disclosed by the invention has the advantages of novel structure, simpleness in equipment manufacturing, low cost, optimized energy layout, energy resource saving, remarkable economic benefits and capabilities of generating partial 0.8-1.5MPa steam as a byproduct by utilizing the waste heat of the gasification furnace, meeting the requirement on a factory for the steam in the pressure range and effectively reducing the consumption of the steam with high pressure level.

Description

Technical field: [0001] The invention belongs to the technical field of energy recovery, and relates to a method for secondary recovery of waste heat of a Lurgi gasifier and a device for realizing the method, which can effectively recover waste heat caused by combustion of various coal gases, and realize energy saving and emission reduction effect. Background technique: [0002] With the continuous rise of oil prices, more and more attention has been paid to the application of coal in the fields of energy and chemical industry. Coal gasification is an effective way to use coal cleanly and efficiently, and it is widely used in industries such as coal-to-gas, synthetic ammonia, and coal-fired power generation; When the coal gas leaves the gasifier, the temperature is generally above 400°C. In order to recover this part of the heat, the current practice is to properly cool the crude gas by spraying water and send it to the waste heat boiler to be used to gasify the boiler feed ...

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Problems solved by technology

[0002] With the continuous rise of oil prices, more and more attention has been paid to the application of coal in the fields of energy and chemical industry. Coal gasification is an effective way to use coal cleanly and efficiently, and it is widely used in industries such as coal-to-gas, synthetic ammonia, and coal-fired power generation; When the coal gas leaves the gasifier, the temperature is generally above 400°C. In order to recover this part of the heat, the current practice is to properly cool the crude gas by spraying water and send it to the waste heat boiler to be used to gasify the boiler feed water to generate a pressure of 0.5-0.7MPa low-pressure steam, so the current waste heat recovery device of Lurgi gasifier can only recover 0.5-0.7MPa low-pressure steam, so in general gasification plants, there is a large surplus of 0.5-0.7MPa steam, and the excess low-pressure steam Steam can only be used as low-value power steam, and the value of steam per ton is only equivalent to 20-30 yuan; on the other hand, with the implementation of new processes such as phenol recovery and low-temperature methanol washing The steam supply of 0.8-1.5MPa required by the device is seriously insufficient, and it is forced to extract steam with a pressure above 2.0MPa from the power zone to replace it, which reduces the value of this part of high-pressure steam; The by-product steam of 0.8-1.5MPa meets the demand of the factory area for steam in this pressure range, reduces the consumption of high-pressure steam, thereby optimizing the current energy layout and improving economic benefits. It is the current solution to the gasification and utilization of coal Research goals for the development of energy waste in

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