A Heat Pump Evaporation Process for Fertilizer Preparation Using Flue Gas Purification By-products

Abstract

The invention provides a heat pump evaporation process for preparing chemical fertilizers by using flue gas purification by-products. After the flue gas is wet-purified, the waste liquid reactor reacts with ammonium bicarbonate. After the reaction is completed, the feed liquid is separated from solid and liquid, and the liquid is cooled. The clear liquid obtained after crystallization is used as the raw material liquid, pumped into the preheater, the preheated raw material liquid enters the heat exchanger, and is heated by the shell side steam in the tube side of the heat exchanger, and the temperature of the raw material liquid is raised in the forced circulation pump. It enters the crystallizer under the impetus of the crystallizer, and flashes in the crystallizer, the raw material liquid is supersaturated and crystallized, and then centrifuged, dried and granulated to obtain compound fertilizer; the secondary steam generated by the flash is compressed by the compressor Then it enters the shell side of the heat exchanger as a heat source. This process not only achieves the purpose of turning waste into treasure, but also saves the consumption of steam; at the same time, the distilled water can be recycled to the desulfurization and denitrification section for water replenishment, saving water.

Description

technical field [0001] The invention relates to the technical field of flue gas purification, in particular to a heat pump evaporation process for preparing chemical fertilizers by utilizing by-products of flue gas purification. Background technique [0002] In recent years, as air pollution has become more and more serious, people have put forward higher requirements for the treatment of flue gas, especially coal-fired flue gas; In accordance with the "Emission Standards for Substances" (GB13223-2011), new emission limits for soot, sulfur dioxide, and nitrogen oxides in flue gas have been put forward. At present, the effective methods of flue gas desulfurization are wet flue gas desulfurization such as ammonia method and sodium method. The above desulfurization methods all produce a certain concentration of waste liquid containing sulfate and nitrate. It has the characteristics of high salt content and partial acidity, and the effluent quality is difficult to meet the dis...

AI Technical Summary

Problems solved by technology

The secondary steam of a certain effect of the patented evaporator cannot be directly used as a heat source for this effect, but can only be used as a heat source for a secondary effect or several effects.

If it is used as the heat source of this effect, additional energy must be given to it to increase its temperature (pressure); and the maximum recycling of resources has not been realized.

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