Dry distillation production process for lignite or high volatile coal

Abstract

The invention discloses a dry distillation production process for lignite or high volatile coal. A high-temperature dry distillation gas serving as a heat carrier enter a dry distillation furnace to transmit heat with coal inside the furnace by contact to change the coal into semicoke through pyrolysis and dry distillation; the gas overflowing through the dry distillation flows into a heat carrier gas and then out of the furnace together; after the gas from the furnace is cooled and purified, which is equivalent to that a part of the original heat carrier gas is heated through a partition to a high temperature to serve as a heat carrier to return to the dry distillation furnace for recycling; and the balance of gas serves as an external supply. The dry distillation production process has the advantages of both internal and external heat dry distillation and obtains the approximately same gas purity as that of the external heat dry distillation process, so that the gas for the externalsupply has a high quality, heat value and application value and is an ideal chemical raw material or high-quality fuel; moreover, all the dry distillation gas can be used for the external supply; thecoal is slightly affected by a temperature and uniformly heated; tar has a high yield; the system has a wide heat source and can use low-quality fuel smoke, such as powdered coal, the gas and the like; and the system has a simple flow, is easy to operate and control in production and operation and has less industrialization construction investment.

Description

Technical field: [0001] The invention relates to a coal dry distillation process. Background technique: [0002] Coal is thermally decomposed into dry distillation products such as gas, tar and coke (or semi-coke) under the condition of isolation of air. According to the difference in the final temperature of the coal material in the furnace, it is generally considered that 500-700 ° C is low-temperature dry distillation, and lignite is low-grade. The coal type is suitable for low-temperature dry distillation processing. Through low-temperature dry distillation processing, lignite can be converted into gas, liquid and solid products, which has good economic and social benefits. The retort furnace is the main equipment in the low-temperature retort production process. According to its heating method, it can be divided into external heat type (partition wall heating) and internal heat type (direct contact heating), and according to the form of heat carrier used, it can be divi...

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Problems solved by technology

However, it is applicable to a single type of furnace (only applicable to shaft furnaces); the requirements for incoming coal are the same as those of traditional air-flow internal heating furnaces, which must be lump coal or briquette coal; Combustion and supplementary heat will greatly reduce the gas volume of the externally supplied product (accounting for only one-third of the total dry distillation gas); and the gas preheating temperature is too high, the energy consumption increases, and the industrialization is more difficult; Thermal preheating or oxygen combustion heating will still cause the retort gas to be diluted by part of the flue gas, which will bring the same or some of the same disadvantages as the traditional airflow internal heating process. The volume of retort gas will increase, and the volume of post-processing equipment and transmission power will follow However, the composition, purity, and calorific value of the externally supplied gas are not as good as those of the externally heated process; in addition, the use of regenerative preheating in this patent will lead to large fluctuations in the furnace temperature and unstable retort operation; The use of oxygen combustion heating requires investment in air separation equipment, increasing investment and operating costs

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