Flash evaporation stripping cooling system and black water treatment process thereof

Abstract

The invention provides a flash evaporation stripping cooling tower. The flash evaporation stripping cooling tower is sequentially provided with a flash evaporation chamber, a liquid phase staying chamber, a stripping chamber, a heat exchange chamber and a separation chamber from bottom to top, wherein the stripping chamber is sequentially provided with a tray section, a liquid phase distributor and a gas phase distributor in the steam flowing direction, a plurality of trays are arranged in the tray section, a heat exchanger section is arranged in the heat exchange chamber, and a plurality of heat exchangers are arranged in the heat exchanger section. The invention further provides a flash evaporation stripping cooling system. The invention also provides a black water treatment process. According to the flash evaporation stripping cooling system and the black water treatment process thereof, equipment integration is achieved, the process is simplified, energy consumption is reduced, theheat transfer effect is improved, low-temperature grey water is used for cooling, graded utilization of the low-temperature grey water is achieved, a large amount of circulating water is saved, and complete recycling of slag water is achieved.

Description

technical field [0001] The invention belongs to the technical field of chemical industry, and relates to a flash stripping cooling system and a treatment process for black water. Background technique [0002] Raw coal gasification is an important measure to realize the comprehensive utilization of coal resources in my country based on the basic national conditions of more coal and less oil. Coal gasification and coal chemical industry are important development directions for the development of my country's chemical industry. Usually raw coal is prepared into pulverized coal or coal-water slurry and then gasified in a gasification furnace. The high-temperature gas (main components of CO, CH4, CO2, H2, etc.) produced is chilled and washed to produce a large amount of black water. The black water roughly contains 0.01-2% solid particles (mainly coal ash, cinder and incompletely reflected coal), the temperature is about 150-250°C, and the pressure is 1.8-10MpaG. At this time, ...

AI Technical Summary

Problems solved by technology

It can be seen that this technology has a lot of equipment and complex operation, occupies a lot of land, and the equipment cost and construction investment cost are relatively large.

Unbearable for general enterprises

[0005] Disclosed in CN109485190A is the processing method of the black water produced by coal gasification and the coal gasification method and its system. On the basis of CN94117093.4, this technology settles the black water after the flocculation treatment, and deposits the supernatant obtained by Filtration treatment and electrodialysis treatment are carried out in sequence, the number of equipment is greatly increased, and the process is more complicated

But it also has obvious disadvantages: (1) The equipment only performs a single heat recovery, and the temperature after preliminary flash evaporation is about 150-200°C, and the effect of recovering heat energy is limited; (2) The gas phase at the top of the equipment A heat exchanger needs to be installed for condensation. The heat exchanger is usually an ABS type floating head heat exchanger with a hook ring. The structure is more complicated and the cost is more expensive.

(3) The gas-phase condensation of this equipment requires a large amount of circulating water; and coal gasification projects are usually located in places where water resources are scarce such as the Northwest, which is not economical and environmentally friendly

(4) After the equipment is condensed, a gas-liquid separation tank needs to be installed for separation, which makes the equipment complicated and the cost increased

(5) The tray of the equipment adopts a single overflow tray, and the application effect is not ideal when the flow rate of the liquid phase is large, and it is easy to cause liquid flooding, etc.

The heat transfer efficiency of this process is relatively low

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