Crushed coal pressurized gasification gas-water separation and recycling system and method capable of recycling sewage

Abstract

The invention provides a crushed coal pressurized gasification gas-water separation and recycling system and method capable of recycling sewage, and belongs to the field of gas separation and recycling. According to the invention, different types of coal gas water are respectively separated and recycled, so that the whole system is small in occupied area, low in investment, low in operation cost,short in treatment flow, less in equipment, less in pollutant discharge points and not easy to cause environmental pollution. By arranging a medium-pressure flash evaporator, a vacuum flash evaporator, a vacuum flash separator, an ammonia distillation tower and other devices and arranging a settling tank and the top of a coal gas water tank to be connected with an inert gas pipeline in a sealed mode, the whole system and the separation and recycling process keep micro-positive-pressure operation larger than 0.2 kPa, and therefore it can be guaranteed that VOCs and odor exhausted from the system can be treated in a centralized mode. The water outlet of the second vacuum flash evaporator is connected with the water inlet of the heat exchanger connected with the waste heat boiler through thepipeline and the water pump, so that recycling of waste water is realized; therefore, the amount of waste water going to biochemical treatment equipment can be reduced, and heat in the waste water canbe fully utilized.

Description

technical field [0001] The invention relates to the technical field of coal gas separation and reuse, in particular to a crushed coal pressurized gasification gas water separation and reuse system and method capable of reusing sewage. Background technique [0002] Crude gas produced by pressurized gasification of crushed coal contains a large amount of water vapor, dust and carbonized by-products, such as tar, light oil, naphthalene, phenol, fatty acid, dissolved gas and inorganic salts, etc., and the temperature is relatively high . Therefore, it needs to be cooled and washed to reduce the temperature and remove harmful substances in the crude gas. During the washing and cooling process of crude gas, these impurity components enter the water, forming gas water with various components in three states of gas, liquid and solid. The content of various ingredients is also not the same. Gas water cannot be directly treated by conventional methods such as biochemistry, filtrati...

AI Technical Summary

Problems solved by technology

[0004] However, with the development of coal gas technology, it is gradually developing in the direction of large-scale, energy-saving, environmental protection, high efficiency and stability. The current gas-water separation and recovery process of the pulverized coal pressurized gasification technology commonly used cannot meet modern requirements, mainly reflected in:

[0005] 1. The existing gas water treatment system collects different types of gas water from different equipment for gas water separation and recovery, resulting in the entire gas water separation and recovery system occupying a large area, high investment, and high operating costs;

[0006] 2. The current gas-water separation and recovery process is long and there are many equipments, resulting in many pollutant discharge points and easy to cause serious environmental pollution;

[0007] 3. Multiple gas-water storage tanks and oil separators are used in the existing gas-water separation and recovery system. These devices are operated under normal pressure, which is likely to cause VOCs (Volatile Organic Compounds, volatile organic compounds) and odorous emissions. Gas, etc. cannot be collected and processed centrally, making the site environment harsh

[0008] 4. The condensed water obtained by heat exchange in the existing gas-water separation and recovery system is often directly discharged as wastewater, which not only makes the amount of wastewater going to the biochemical treatment equipment relatively large, but also cannot make full use of the heat in the condensate

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