Gas condensation recovery system and control method

Abstract

The invention discloses a gas condensation recovery system and a control method. The gas condensation recovery system comprises a first-stage refrigeration system, a second-stage refrigeration system and a recovery pipeline system, a pressure maintaining valve enables the evaporation temperature in a first-stage evaporator to be higher than 0 DEG C, and a first refrigerant flowing in the first-stage refrigeration system is different from a second refrigerant flowing in the second-stage refrigeration system; the secondary evaporator is arranged in the primary evaporator, so that the evaporation temperature in the secondary evaporator is lower than that in the primary evaporator, gas sequentially passes through the primary evaporator and the secondary evaporator through the recovery pipeline system and is dehumidified in the primary evaporator, and VOCs are separated from the secondary evaporator. According to the gas condensation recovery system, by means of a two-stage refrigeration mode of first dehumidification and then separation, VOCs are removed, meanwhile, the frosting and icing phenomena of an evaporator can be relieved, quick and energy-saving defrosting and deicing are conducted through a defrosting pipeline and an ice melting pipeline after frosting and icing, an evaporative condenser is arranged between the two stages of refrigeration systems to form cascade refrigeration, and the refrigeration efficiency is improved. And the refrigeration energy consumption is reduced.

Description

technical field [0001] The invention relates to the fields of environmental protection and harmful gas separation and treatment, in particular to a gas condensation recovery system and a control method. Background technique [0002] VOCs (volatile organic compounds) are short for volatile organic compounds, which exist in a variety of factory exhaust and equipment exhaust, which can cause harm to the environment and human body. One of the widely used methods for recovering VOCs in gas is the condensation method. [0003] The refrigeration system currently used in the market often encounters the problem of easy frost formation during operation and use. The main reason is that the gas composition containing VOCs is generally complex, and contains a certain proportion of moist air, alkanes, olefins and other components. In order to condense and separate VOCs, the temperature of the cold side generally needs to be lower than -40°C. During the cooling process, the moisture in t...

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Problems solved by technology

Frosting and freezing will increase the heat transfer resistance of the heat exchanger, reduce the heat exchange effect and cooling capacity, make the outlet temperature and condensation capacity of the heat exchanger fail to meet the requirements, and even cause the entire refrigeration system to fail to operate normally. Therefore, it is necessary to regular defrosting

However, if the defrosting interval is too short and the defrosting duration is too long, it will have a greater negative impact on the continuity and effect of the condensation recovery process. Therefore, in engineering, two evaporators that operate independently are usually required to be switched and put into use. To ensure the continuity of the condensation process and the stability of the condensation temperature, but this method results in high equipment costs and high energy consumption

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