Method for recovering ammonia and synthesis gas from coking wastewater

Abstract

The invention discloses a method for recovering ammonia and synthesis gas from coking wastewater. The method comprises the following steps: (1) entering coking wastewater and a certain amount of alkali into an ammonia evaporator; passing the fluid on the top of the ammonia evaporator through a stronger ammonia water storage tank by virtue of a dephlegmator and a condenser orderly to achieve recovery of ammonia, and entering bottom fluid into a wastewater concentrator; (2) entering the fluid on the top of the wastewater concentrator into a deep treatment section via a heat exchanger, entering the bottom fluid into a supercritical water gasification reactor through a compressor and a heating furnace orderly, and meanwhile, and entering oxygen into the supercritical water gasification reactor via an oxygen compressor; (3) entering the fluid gasified by the supercritical water into s a gas-liquid separator through the heat exchanger and a reducing valve orderly; and (4) entering the bottom fluid of the gas-liquid separator into the deep treatment section, entering the top fluid into a CO2 absorption tower, and meanwhile, diluting a part of fluid in the stronger ammonia water storage tank is together with dilution water in a diluted ammonia water storage tank, and then entering into the CO2 absorption tower via a centrifugal pump, recovering the synthesis gas from the top of the tower, and recycling the ammonium carbonate solution at the bottom of the tower.

Description

technical field

[0001] The invention belongs to the resource utilization technology of organic waste liquid, in particular to a method for recovering ammonia and synthesis gas by supercritical water gasification treatment of coking waste water. Background technique

[0002] In recent years, the coking industry and coal gasification industry have developed vigorously. However, a large amount of coking wastewater is produced in the process of coke production, gas washing, cooling, purification, recovery and refining of chemical products. The main characteristics of coking wastewater are high concentration of phenol and ammonia and large amount of wastewater discharge. The chemical oxygen demand (COD) in wastewater is as high as 20000mg / L, among which phenolic substances account for more than 70% of COD. Due to the biological toxicity of phenolic substances and the biological inhibition of ammonia nitrogen, the biodegradability of coking wastewater is poor, and its five-day b...

Examples

Embodiment Construction

[0031] The present invention will be further described in detail below in conjunction with the accompanying drawings and specific embodiments.

[0032] refer to figure 1 , the treatment capacity is 5t / h of coking wastewater, in which COD is 20000mg / L, and the concentrations of phenol and ammonia are 8000 and 7000mg / L respectively. The coking waste water 24 to be treated first enters the ammonia distiller 1, and at the same time, an appropriate amount of 10% NaOH solution is added to the ammonia distiller 1 to adjust the pH of the wastewater in the ammonia distiller to 11. Turn on the heater 2 at the bottom of the ammonia distiller to raise the temperature of the waste water to 80°C, and the top fluid (mainly NH 3 and water vapor) is condensed to 70°C through the compressor 3, then cooled to normal temperature through the condenser 4, and then enters the concentrated ammonia water storage tank 5. The fluid at the bottom of the ammonia distiller 1 enters the waste water concen...

technical field

[0001] The invention belongs to the resource utilization technology of organic waste liquid, in particular to a method for recovering ammonia and synthesis gas by supercritical water gasification treatment of coking waste water. Background technique

[0002] In recent years, the coking industry and coal gasification industry have developed vigorously. However, a large amount of coking wastewater is produced in the process of coke production, gas washing, cooling, purification, recovery and refining of chemical products. The main characteristics of coking wastewater are high concentration of phenol and ammonia and large amount of wastewater discharge. The chemical oxygen demand (COD) in wastewater is as high as 20000mg / L, among which phenolic substances account for more than 70% of COD. Due to the biological toxicity of phenolic substances and the biological inhibition of ammonia nitrogen, the biodegradability of coking wastewater is poor, and its five-day b...

Examples

Embodiment Construction

[0031] The present invention will be further described in detail below in conjunction with the accompanying drawings and specific embodiments.

[0032] refer to figure 1 , the treatment capacity is 5t / h of coking wastewater, in which COD is 20000mg / L, and the concentrations of phenol and ammonia are 8000 and 7000mg / L respectively. The coking waste water 24 to be treated first enters the ammonia distiller 1, and at the same time, an appropriate amount of 10% NaOH solution is added to the ammonia distiller 1 to adjust the pH of the wastewater in the ammonia distiller to 11. Turn on the heater 2 at the bottom of the ammonia distiller to raise the temperature of the waste water to 80°C, and the top fluid (mainly NH 3 and water vapor) is condensed to 70°C through the compressor 3, then cooled to normal temperature through the condenser 4, and then enters the concentrated ammonia water storage tank 5. The fluid at the bottom of the ammonia distiller 1 enters the waste water concen...

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