Ammonia separation device and method

Abstract

The invention discloses an ammonia separation device and method. The ammonia separation device comprises a heat exchange evaporator, a gas cooler, an absorption tower, a gas-liquid separator, an absorbent cooler, a high-pressure pump, a flash evaporator, a connection pipe and two process switching valves. In a catalyst heating and reducing stage, gas from the tower sequentially passes through the gas cooler, the heat exchange evaporator and the gas-liquid separator and returns a system to recycle after being separated from an ammonia water mixture; in a production stage, gas from the tower sequentially passes through the heat exchange evaporator, the gas cooler, the absorption tower and the gas-liquid separator and then is recycled after so ammonia products are seperated, and the absorbent sequentially passes through the absorption tower, the flash evaporator, the heat exchange evaporator, the absorbent cooler and the high-pressure pump so as to finish absorption and ammonia desorption processes and then is recycled; and all devices are connected and switched through pipes and the process switching valves. Compared with the condensed ammonia separation, the ammonia separation device and method disclosed by the invention can realize respective recycle of recycle gas and the absorbent and high-efficiency separation of products and str remarkable in energy-saving and consumption-reducing effects.

Description

technical field [0001] The invention relates to a fertilizer production device, in particular to an ammonia separation device and method. The device and its method are especially suitable for ammonia separation and production of synthetic ammonia. Background technique [0002] In the classic ammonia synthesis separation system, a certain proportion of hydrogen and nitrogen mixed gas reacts in the ammonia synthesis tower to form a mixed gas with a certain concentration of ammonia (mainly hydrogen, nitrogen, ammonia and a small amount of inert gas, which is called the outlet of the tower here. Gas), the ammonia content is generally 10~20% (v). In order to recycle most of the unreacted hydrogen and nitrogen mixed gas, it is necessary to separate the ammonia in the reacted mixed gas as an ammonia product, and the remaining hydrogen and nitrogen mixed gas (called cycle gas) is returned to the synthesis tower for recycling. At present, the ammonia separation device used in the i...

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Problems solved by technology

[0003] The existing refrigerated ammonia separation devices generally have the following problems: 1. The separation efficiency is relatively low: there are still 2.0-3.2% (v) of ammonia in the separated recycle gas that cannot be separated, and the recycle gas enters the system to circulate, increasing 2. High coal consumption of raw materials: In order to maintain system pressure and normal production, a certain amount of inert gas needs to be discharged. During this process, hydrogen and nitrogen are also produced. 3. Ammonia condenses in the ammonia cooler and consumes a lot of refrigeration work. Therefore, although the frozen ammonia separation device has been improved many times, its energy consumption is always high

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