Method for reducing production energy consumption of sulfuric acid and phosphoric acid

Abstract

The invention discloses a method for reducing the production energy consumption of sulfuric acid and phosphoric acid, which comprises the following steps: combing a sulfuric acid system and a phosphoric acid system, using dilute phosphoric acid as a cooling medium for replacement of cooling water, cooling sulfuric acid to reduce the energy consumption of sulfuric acid; simultaneously, heating dilute phosphoric acid by sulfuric acid, evaporating moisture, raising the concentration without heating by using steam to reduce the energy consumption of phosphoric acid. The method has the beneficial effects of concise technology, practicality, simple technology reconstruction and less investment; a cooling water system for producing sulfuric acid and a heating steam supply system for producing phosphoric acid can be omitted through reconstruction, so that the method of the invention has the advantages of greatly reducing the energy consumption, reducing the equipment investment and land occupation of enterprises, and possessing substantial economical effect.

Description

technical field [0001] The invention relates to a production process of sulfuric acid and phosphoric acid, in particular to a method for reducing energy consumption in the production of sulfuric acid and phosphoric acid. Background technique [0002] In the acid factory, the sulfuric acid system and the phosphoric acid system are isolated systems, not connected with each other, and have the following disadvantages: [0003] Sulfuric acid absorption reaction is exothermic , the current technology used is to circulate and cool the sulfuric acid with water so that it can continuously absorb SO 3 , to obtain high-concentration sulfuric acid, because the sulfuric acid absorption reaction releases a lot of heat, the outlet temperature of the absorption tower is as high as 100 ° C, the consumption of cooling water is also large, and the energy consumption of pumping water is very high, which is an important part of the cost of sulfuric acid. At the same time, in order to save wa...

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Problems solved by technology

[0003] Sulfuric acid absorption reaction is exothermic , the current technology used is to circulate and cool the sulfuric acid with water so that it can continuously absorb SO 3 , to obtain high-concentration sulfuric acid, due to the large amount of heat released by the absorption reaction of sulfuric acid, the outlet temperature of the absorption tower is as high as 100°C, the consumption of cooling water is also large, and the energy consumption of pumping water is very high, which is an important part of the cost of sulfuric acid

At the same time, in order to save water resources, circulating water is usually used to cool sulfuric acid, so it is necessary to build a huge circulating pool, equipped with cooling water towers, water pumps and other facilities, which covers a large area and requires high investment in civil engineering and equipment

Not only that, the exhaust gas temperature of sulfuric acid is as high as 80 ℃, and the huge heat contained in it is wasted in vain

[0004] The current phosphoric acid production process is to prepare dilute phosphoric acid slurry by adding water to phosphate rock powder. The clear liquid is separated by sedimentation, and then concentrated by steam heating to evaporate the water in the dilute phosphoric acid to obtain high-concentration phosphoric acid. Due to the concentration of dilute phosphoric acid very low (usually its P 2 o 5 Content is about 20%), to obtain high concentration of phosphoric acid, it will consume a lot of steam, the cost is very high

At the same time, facilities such as steam boilers need to be configured, and the investment is very high

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