Low-rank coal downward circulating fluidized bed pyrolysis quality improvement process

Abstract

The invention provides a low-rank coal downward circulating fluidized bed pyrolysis quality improvement process. A low-rank coal is dried and raised by a gas raising pipe, low-rank coal particles separate from each other in a hierarchical mode, flue gas exhausts outwards, fine particles enter a downward hybrid tube of low-rank coal quality improvement, and self-mixing, temperature rising and pyrolysis of large-medium particle low-rank coals with high temperature cycling carbocoal is achieved quickly at the top end of a downward pyrolytic reactor. Oil gas quickly separates from the carbocoal under a reactor vertical pipe. Through a condenser, a liquid product and coal gas are obtained from pyrolytic oil gas. The carbocoal is divided into two parts through a sub-material valve. Part of carbocoal flows into the downward hybrid tube of the low-rank coal quality improvement, and part of carbocoal enters a burning raising pipe and is burned and heated. High temperature carbocoals separate from each other in a hierarchical mode. The flue gas preheats air, and then is led to the bottom of the flue gas raising pipe to promote and dry a low-rank coal with a size less than six millimeters. The large-medium particles enter the top portion of the downward pyrolytic reactor to act as the high temperature cycling carbocoal. Fine carbocoal inflows the hybrid tube of the low-rank coal quality improvement and mixes with the low-rank coal and exchanges heat with the low-rank coal, and further, the fine carbocoal partially softens and pyrolyzes a thermoforming machine to produce a quality improvement type coal.

Description

1. Technical field [0001] The invention provides a low-rank coal descending circulating fluidized bed pyrolysis upgrading process, which belongs to the field of coal chemical industry. 2. Background technology [0002] my country has abundant low-rank coal reserves, which have the characteristics of high water content, high oxygen content, high volatile matter, and low calorific value. Under the conditions of modern large-scale mechanized mining, a lot of pulverized coal is easy to weather and spontaneously combust, and most of the production areas are in remote areas. The region and inconvenient transportation make low-rank coal unsuitable for long-distance transportation, and its application is greatly restricted. At present, most of the low-rank coal in my country is used for direct combustion for power generation, causing serious environmental pollution and a large amount of greenhouse gas emissions, low power generation efficiency, low comprehensive utilization rate of c...

AI Technical Summary

Problems solved by technology

However, the existing low-rank coal solid heat carrier rapid pyrolysis technology has problems such as ash in oil, high-temperature wear of mechanical moving parts, device amplification effect, and long-term stable operation of equipment, which has become a technical bottleneck restricting low-rank coal rapid pyrolysis. According to the pyrolysis reaction characteristics of low-rank coal, develop low-rank coal pyrolysis upgrading technology and equipment that can eliminate ash in oil, have good heat transfer and reasonable energy utilization

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