Polygeneration technology for gradient utilization of low-rank coal

Abstract

The invention discloses a polygeneration technology for gradient utilization of low-rank coal. According to the polygeneration technology, a circulating fluidized bed combustion boiler, a circulating fluidized bed dry distillation reactor and a circulating fluidized bed gasification reactor are taken as cores; series power generation equipment achieves gradient cyclic utilization of low metamorphic coals; the low-rank coal is firstly subjected to lignite wax extraction after crushing and drying, and then enters a brown coal pyrolysis reactor; a raw gas of the gasification reactor is adopted as a fluidizing agent; tar and the raw gas are obtained after dry distillation; semicoke enters the gasification reactor to carry out partial gasification; a part of coal gas is generated as a fluidizing agent of a dry distillation reactor; incompletely gasified semicoke enters the combustion boiler as a fuel; heat and steam generated by combustion are applied to power generation; a by-product low-pressure steam can be used as a raw material of the gasification reactor; the high-temperature semi-coke and hot ashes obtained by combustion enter the dry distillation reactor and the gasification reactor as heat carriers, so as to finish a cycle. By adopting the polygeneration technology, the economic value of the low-rank coal can be obviously improved, emission of pollutants can be significantly reduced by gradient cyclic utilization, and the technology is safe and reliable.

Description

technical field [0001] The invention relates to a low-level cascade utilization polygeneration process, which can be used in the technical field of comprehensive and high-efficiency utilization of lignite and other low-quality coals, and in particular relates to a process for cogeneration of electricity, steam, gas, tar and semi-coke by cascade recycling of lignite. Background technique [0002] Coal is the main energy resource in my country. In recent years, large-scale coal fields have been continuously discovered in Inner Mongolia, Yunnan, Xinjiang and other places, mainly low-rank coal (lignite accounts for the vast majority). High coal, high volatile content, low calorific value, is often regarded as low-quality fuel steam coal; in addition, it is easy to oxidize and spontaneously ignite, and is not suitable for long-distance transportation, so it has become a coal resource that is difficult to process and utilize in different places. How to efficiently utilize these res...

AI Technical Summary

Problems solved by technology

[0006] The current polygeneration process mainly focuses on coal gasification / combustion cogeneration, or dry distillation / combustion combined heat and electricity cogeneration, often without carbonization / gasification / combustion combined heat and power cogeneration

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