Liquid ammonia safety protection control method

Abstract

The invention discloses a liquid ammonia safety protection control method. During DCS normal control, when a liquid ammonia safety protection control system is in an automatic state, a liquid ammoniagas alarm gives an alarm when detecting that the liquid ammonia concentration reaches the set alarm high limit values E and F; when the liquid ammonia concentration reaches the set alarm high-high limit values G and H or when the liquid ammonia pressure reaches the set alarm high limit values I and J, an alarm is given; and when the liquid ammonia concentration reaches the set alarm high-high limit values M and N, exhaust fan interlocking, spraying system interlocking, induced air emergency interlocking, liquid ammonia pressure tank interlocking and axial flow fan matched interlocking are started. Any above operation can be manual operation. When the indoor temperature is high, a spraying system can be manually started for manual cooling; when a DCS is abnormal or the whole system is in apower losing state, the liquid ammonia safety protection control system can start a spraying emergency system; and during abnormality, the spraying emergency system can be manually executed in a one-key manner. According to the above control method, liquid ammonia storage, safety protection and emergency control operation are facilitated, and the control method is suitable for liquid ammonia safety

Description

technical field [0001] The invention relates to a method for controlling the production and storage of liquid ammonia in the field of industrial liquid ammonia production process, in particular to a control method for the safety protection and emergency of liquid ammonia in the production of liquid ammonia. Background technique [0002] At present, the known liquid ammonia production process technology is very mature. Liquid ammonia is mainly used in nitric acid, urea and other chemical fertilizers, as a raw material for medicine and pesticides, and as a refrigerant. At present, due to the large number of cold storage equipment and complex refrigeration processes, the demand for liquid ammonia is increasing day by day, and ammonia is in a gaseous state at room temperature, and it can be converted into a liquid state by cooling it to -33.4°C under normal pressure or pressurizing it to 1.554 MPa at room temperature , when a leak occurs, part of the liquid ammonia rapidly vapo...

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Problems solved by technology

[0003] 1. The volatile gasification of liquid ammonia and the convenience of transportation and storage of liquid ammonia are easier than gas. If leakage occurs, it is easy to cause combustion explosion or poisoning accidents, and if it is not handled carefully, it will cause serious consequences;

[0004] 2. Liquid ammonia is easy to pollute the environment, and secondary explosions occur when exposed to high temperature conditions. Therefore, it is very difficult to dispose of and cool down;

[0005] 3. At the moment of power failure, and at this time all UPS power is lost, the complex control system will often open all valves or be in an unknown state during power failure, which may cause a large amount of ammonia gas to gush out, resulting in immeasurable losses and potential safety hazards

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