A method for producing synthetic ammonia from furnace gas produced by kiln method or blast furnace method to produce phosphoric acid

Abstract

The invention relates to a method of producing synthesis ammonia by using furnace gas produced when phosphoric acid is produced in a kiln method or a blast furnace method. The method of producing the synthesis ammonia comprises the following steps that the furnace gas produced when the phosphoric acid is produced in the kiln method or the blast furnace method is cooled in a water bath mode so that phosphorus steam and most of dust can be removed, then the furnace gas passes through a venturi tube and a fiber demister successively, dust removal is conducted, and tail gas is obtained; desulfuration is conducted on the tail gas in a wet oxidation method, the tail gas enters a conversion procedure after being desulfurated, and the conversion procedure comprises the steps that carbon monoxide in the tail gas reacts with water to produce hydrogen gas in the presence of a catalyst and feed gas of the synthesis ammonia is obtained by mixing the hydrogen gas and nitrogen gas of which the molar ratio is 2.5-2.9:1; desulfuration, decarbonization and gas purification are conducted on the feed gas of the synthesis ammonia, then the feed gas of the synthesis ammonia enters a synthetic tower, and the synthesis ammonia is produced. According to the method of producing the synthesis ammonia, after phosphorous slurry is recycled, the furnace gas produced when the phosphoric acid is produced in the kiln method or the blast furnace method is used as raw materials of the synthesis ammonia, materials are utilized comprehensively, and the tail gas is prevented from being discharged and polluting the environment; processes are simple, the utilization rate of raw materials is high, and good social benefits and economic benefits are obtained.

Description

technical field [0001] The invention relates to a method for producing synthetic ammonia by utilizing furnace gas produced by a kiln method or a blast furnace method to produce phosphoric acid, and belongs to the technical field of resource comprehensive utilization and synthetic ammonia. Background technique [0002] The industrial production process of phosphoric acid is mainly divided into three types: wet process phosphoric acid, thermal process phosphoric acid and kiln process (or blast furnace process) phosphoric acid. Kiln method (or blast furnace method) phosphoric acid refers to the direct reduction of phosphate rock to produce phosphoric acid by using carbon as a reducing agent and materials containing silica as an auxiliary agent. With the depletion of phosphate rock resources in our country, high-grade phosphate rock will be exhausted in about ten years. Kiln method (or blast furnace method) phosphoric acid can directly produce phosphoric acid with medium and low...

AI Technical Summary

Problems solved by technology

[0003] The main components of the kiln (high) furnace gas in the kiln method (or blast furnace method) phosphoric acid are phosphorus vapor, dust, nitrogen and carbon monoxide. In the existing process, the kiln (high) furnace gas is directly discharged after air oxidation to recover phosphorus. The dust will pollute the atmosphere, and a large amount of carbon dioxide emitted after oxidation will have a greater impact on the environment

Chinese patent document CN101767779A (application number 200910300004.0) discloses a method of producing phosphoric acid using a blast furnace and the equipment used. The patent document shows that the dust in the blast furnace gas also contains a large amount of phosphorus. Sludge phosphorus is recovered, and sludge phosphorus is oxidized and burned to prepare phosphoric acid. The recovery rate of phosphorus in this process is increased to 98%, but the tail gas after dust removal is directly discharged, causing pollution to the environment.

[0004] According to literature search, there is no public report on the synthesis of ammonia from furnace gas using kiln method or blast furnace method to produce phosphoric acid

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