Production method of nitric acid and device thereof

Abstract

The invention relates to a production method of nitric acid and a device thereof, and the method comprises the following steps: raw material liquid ammonia is evaporated into gaseous ammonia, the gaseous ammonia enters a gaseous ammonia superheater, the gaseous ammonia exchanges heat with oxynitride shunted from an oxidation furnace in the gaseous ammonia superheater, the oxynitride heats the gaseous ammonia, and the gaseous ammonia cools the oxynitride; the heated gas ammonia passes through an ammonia-air mixer and then enters an oxidizing furnace to react to generate the oxynitride, and the oxynitride is respectively introduced into the gas ammonia superheater and the energy saver; the oxynitride cooled by the gas ammonia is mixed with the oxynitride cooled by the energy saver, and sequentially enters a low-pressure reaction water condenser, a fine separator, a compressor, a high-pressure reaction water cooler and an absorption tower to produce nitric acid, so that the consumption of steam is remarkably reduced, coal resources are saved, and the yield of finished products is improved while the resource utilization rate is improved.

Description

technical field [0001] The invention relates to the field of nitric acid production, in particular to a nitric acid production method and device. Background technique [0002] At present, the production of dilute nitric acid mostly adopts the double pressurization method. The raw material liquid ammonia from the boundary area needs to be heated by the gas ammonia superheater after being evaporated. The purpose is to prevent the gas ammonia from being mixed with liquid in the oxidation furnace. Unevenness, resulting in serious damage to the platinum grid due to uneven heating, or at a certain moment, the ammonia air ratio is too high, resulting in interlock shutdown. However, the existing gas ammonia superheating process usually passes low-pressure steam (0.69MPa·G, 168°C) into the gas ammonia superheater to heat the gas ammonia. The use of low-pressure steam for superheating leads to excessive steam consumption and increases Environmental protection pressure, in the nitric ...

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Problems solved by technology

[0002] At present, the production of dilute nitric acid mostly adopts the double pressurization method. The raw material liquid ammonia from the boundary area needs to be heated by the gas ammonia superheater after being evaporated. The purpose is to prevent the gas ammonia from being mixed with liquid in the oxidation furnace. Uneven, resulting in serious damage to the platinum grid due to uneven heating, or at a certain moment, the ammonia air ratio is too high, resulting in interlock shutdown

However, the existing gas ammonia superheating process usually passes low-pressure steam (0.69MPa·G, 168°C) into the gas ammonia superheater to heat the gas ammonia. The use of low-pressure steam for superheating leads to excessive steam consumption and increases Environmental protection pressure, in the production process of nitric acid, the daily consumption of low-pressure steam is about 160 tons, and the load can only be increased to meet the production demand, so a large amount of coal resources will be consumed

[0003] In the double pressurization process, the boiler water circulating in the economizer is used to reduce the temperature of nitrogen oxides. The temperature of the nitrogen oxides after cooling is not ideal and cannot meet the required temperature requirements, resulting in the bottom of the low-pressure reaction water condenser. The temperature and the temperature at the inlet of the compressor are too high, which not only wastes the heat source, but also increases the load on the subsequent cooling process, which greatly increases the amount of circulating water required by the low-pressure reaction water condenser, and the nitrogen oxide gas compressed by the compressor is due to The high base temperature further causes the temperature of nitrogen oxides at the outlet of the high-pressure reaction water cooler to be high

In addition, the high temperature of nitrogen oxides entering the absorption tower will reduce the absorption efficiency, resulting in large energy consumption and affecting the yield of finished products

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