Efficient coal-water slurrygasification ash water treatment method

Abstract

The invention provides acoal-water slurrygasification ash water treatment method. The method comprises the steps as follows: 1, coal-water slurrygasification ash water enters a reaction tank, the pH is adjusted to be at least 11 through alkali addition, theash water is sent to a sedimentation tank after a flocculating agent is added, and a supernatant liquid of the ash water is sent to a steam stripping unit; 2, thesteam stripping unit includes steam stripping andheat recovery: a) the ash water entering a steam stripping tower is sprayed by an inlet distributor, steam-liquid mass and heat transfer is performed under the action of parts inside the tower, and the purpose of ammonia-nitrogen separation is achieved; b) a tower top condenser is arranged at the top of the steam stripping tower to condense a gas phase at the tower top into ammonia water; c) low-pressure steam enters the steam stripping tower through a steam inlet distribution pipe at the bottom of the steam stripping tower; d) the treated ash water led out of the bottom of the steam stripping tower is subjected to one-stage or two-stage flash distillation, the treated ash water and the untreated ash water are sent to the steam stripping towerthrough a steam stripping towerfeeding pump after being subjected to direct steam-liquid heat-exchange warming through one-stage or two-stage spraying; 3, the pH of the ash water subjected to steam stripping is adjusted to be in a range of 6-9, then the ash water is sent to a biochemical treatment unit, and the ash water reaches the standard and is drained after being treated with an SBR (sequencing batch reactor) or A / O (anoxic / oxic) process.

Description

technical field [0001] The patent of the present invention relates to a treatment method for coal-water slurry gasification gray water. Background technique [0002] According to the "China's Energy Status and Policies" issued by the State Council Information Office of China, China has relatively rich fossil energy resources. Among them, coal dominates. In 2006, the reserves of coal reserves amounted to 1.0345 billion tons, and the remaining proven recoverable reserves accounted for about 13% of the world's total, ranking third in the world. [0003] Coal is the non-renewable strategic resource with the largest reserves and the widest distribution in China. According to the latest forecast of the Ministry of Land and Resources, the recoverable reserves of coal in my country will reach 204 billion tons, while the recoverable reserves of oil and natural gas will be 21.2 billion tons and 220,000 cubic meters respectively. Far lower than the usable amount of coal, this coal-bas...

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Problems solved by technology

[0019] However, the patent No. CN200810104999.9 is characterized by a multi-stage stripping deamination tower, and the heat at each level is rationally utilized, which reduces the energy consumption of deamination. The tendency is serious, the reboiler of the tower kettle will be fouled and blocked, and cannot run stably for a long period of time

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