Coal gasification method

Abstract

The invention provides a coal gasification method. The coal gasification method comprises the following steps: grinding the coal, drying, pressurizing and transporting the pulverized coal, and gasifying the pulverized coal in a gasification furnace. On the model selection of a coal grinder, primary air entering the coal grinder from a hot blast heater is annularly distributed, the temperature of the hot air entering the coal grinder is ensured to be higher than the conversion temperature of brown coal, the local surface of the brown coal is ensured not to be overheated, and the escape of volatile components in the brown coal can be reduced; the high-volatility brown coal is adopted as a raw material, the coal grinding system is controlled, the maximum concentration of oxygen is 4 percent, a new flow of low-pressure nitrogen is supplemented to a coal grinder sealing system, an nitrogen inlet in the system is also increased, the impact on a grinding roll is reduced, and the vibration of the coal grinder is reduced; the combustion temperature in the gasification furnace is 150 to 200 DEG C higher than the flowing temperature of lime-ash. Under the temperature and pressure, not only can the conversion rate of carbon in the gasification furnace be ensured to reach 99 percent, but also the lime-ash is good in flow characteristic.

Description

technical field [0001] The invention relates to a coal gasification method, which belongs to the field of coal chemical industry. Background technique [0002] Coal is an abundant resource. Coal gasification is an efficient and clean coal utilization method. Coal gasification technologies commonly used today include oxygen-enriched continuous gasification, fluidized bed gasification, and two-stage pressurized gasification of dry pulverized coal. But above-mentioned technology all has defect. [0003] Oxygen-enriched continuous gasification has the following disadvantages: [0004] (1) The oxygen used in this process requires the construction of an air separation unit, which requires high investment and high cost of oxygen production. This is the most important reason for restricting the development of continuous oxygen-enriched gasification and the small and medium-sized synthetic ammonia plants adopting this process. [0005] (2) The composition of oxygen-enriched conti...

AI Technical Summary

Problems solved by technology

[0004] (1) The oxygen used in this process requires the construction of an air separation unit, which requires high investment and high cost of oxygen production. This is the main reason for restricting the development of continuous oxygen-enriched gasification and the fact that small and medium-sized synthetic ammonia plants use this process.

[0005] (2) The composition of oxygen-enriched continuous gasification gas is poor, with carbon dioxide content as high as 15-20%, methane content as high as 2%, and the gas contains organic substances such as benzene and naphthalene

Bring great problems to the follow-up section

Especially the problem of methane and organic matter, there is no good solution at present

[0006] (3) It is difficult to control the oxygen content in the oxygen-enriched continuous gasification gas composition, which brings safety hazards to the subsequent sections

[0010] The gasifier adopts a water-cooled wall structure, and its disadvantage is that the CH in the syngas 4 The content is high, which is unfavorable for the production of ammonia, methanol and hydrogen