An energy-saving negative pressure deamination method for coking residual ammonia water

Abstract

A related energy-saving type negative-pressure deamination method of coked residual ammonia water comprises the following steps, concretely, residual ammonia water is conveyed into a liquid distributor at the upper part of the stripping section of a deamination tower, and flows through the stripping-section filler layer from top to bottom after liquid distribution is finished; a stripping medium and heat energy are provided by secondary steam which is produced by means of condensation heat releasing of ammonia-water-containing steam at the tower top and a part of circulation diluted ammonia water heat energy and is subjected to heating pressurization by a water-vapor compressor. In the deamination tower, under a negative pressur of 43.64-53.41 KPa, secondary steam passes through the stripping-section filler layer from bottom to top and is contacted with reversely-flowing residual ammonia water for deaminating the residual ammonia water. When the residual ammonia water reaches the tower bottom, a deaminated qualified liquid according to requirements is formed and then is pumped out from the tower. When secondary steam reaches the top of the deamination tower, majority of ammonia gas is absorbed, then secondary steam is led out from the deamination tower and enters a condenser, crude ammonia gas pumped out from the condenser is introduced to an ammonium sulfate saturator for preparing ammonium sulfate, and condensed concentrated ammonia water with the concentration of 15% is pumped into a concentrated ammonia water storage tank for usage.

Description

technical field [0001] The invention belongs to the field of waste water treatment in chemical industries such as coal chemical industry and petrochemical industry, and in particular relates to an energy-saving deammonization method in which coking residual ammonia water containing ammonia gas is deaminized by negative pressure, and a comprehensive utilization method of the removed ammonia gas. Background technique [0002] During the cooling and washing process of coke production and coal gasification in coal chemical industry and other chemical enterprises, a large amount of dilute ammonia water containing ammonia, phenol, cyanide, and sulfide is formed. After removing coal dust, coal powder, and tar, this part of the wastewater is used as cooling water The water is recycled in the system, which is called circulating ammonia water; as the number of cycles increases, harmful components such as ammonia nitrogen are enriched, and part of it must be discharged regularly, and pa...

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Problems solved by technology

However, in the use of this method, for the situation that the sulfide content in the residual ammonia water of the enterprise is relatively high, because the temperature in the deammonization tower is only 60-65 ° C, it is difficult to decompose the sulfide in the residual ammonia water (the higher the temperature, the more It is beneficial to the decomposition of sulfides), so that the qualified liquid after deammonization has a high content of sulfides, and it is difficult for the subsequent residual ammonia water biochemical treatment system to meet the standard. The temperature inside the deamination tower increases steam consumption; after repeated adjustment tests, when the temperature in the deamination tower is maintained above 75°C, the problem of high sulfide content in the qualified liquid can be better solved: even if the sulfide decomposes to a certain extent, the deamination tower The sulfide content in the qualified liquid can be treated up to the standard by the subsequent biochemical treatment system, and the sulfide content in the ammonia gas extracted from the gas can be consumed by the ammonium sulfate saturator system of the enterprise, so that the quality of the ammonium sulfate produced will not be affected. The premise is that the ammonia gas from gas stripping must pass through the company’s original saturator that can produce a large amount of ammonium sulfate to produce ammonium sulfate, and it is not possible to set up a separate saturator for the ammonia-containing steam from gas stripping. In that case, the produced sulfuric acid Ammonium may turn yellow due to too much sulfide; of course, if the enterprise itself needs ammonia water for desulfurization, it can also directly extract a part of ammonia water from the condenser for desulfurization, because when it is used for desulfurization, the sulfide content in ammonia water is higher Basically no impact

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