A system and method for recycling low-pressure exhaust gas of chemical industry

Abstract

The invention discloses a low-pressure chemical tail gas recycling system and method. The system comprises a tail gas buffer separation tank, a tail gas combustion tank and a waste heat recovery system, wherein the tail gas buffer separation tank comprises a low-pressure tail gas inlet, a tail gas outlet and an overpressure automatic discharge device; the low-pressure tail gas inlet and the tail gas outlet are arranged at the lower end and the upper end of the tail gas buffer separation tank correspondingly. The overpressure automatic discharge device comprises a pressure sensor, a controller and an exhaust valve. The pressure sensor is arranged in the tail gas buffer separation tank. The exhaust valve communicates with the tail gas buffer separation tank through a pipeline. The pressure sensor and the exhaust valve are connected with the controller. The pressure upper limit is input into the controller. The upper end of the tail gas combustion tank is provided with at least one combustor. The tail gas outlet communicates with the combustors through a pipeline. A valve is arranged on the pipeline. The tail gas combustion tank is connected with the waste heat recovery system through a pipeline. The waste heat recovery system conducts heat recovery on flue gas obtained after combustion of low-pressure tail gas.

Description

technical field [0001] The invention belongs to the technical field of energy, and in particular relates to a system and a method for recycling low-pressure exhaust gas of a chemical industry. Background technique [0002] In the process of chemical production, a part of continuously discharged exhaust gas will be generated, and the exhaust gas contains certain effective components. For some high-pressure exhaust gases, technologies such as absorption, membrane separation or pressure swing adsorption can be used for separation, purification and recycling, but for some low-pressure exhaust gases The tail gas, and some high-pressure tail gas after recovery treatment, are difficult to recover the effective components in the low-pressure tail gas due to the low content of effective components, low pressure and complex composition. Some chemical low-pressure tail gas contains combustible gas components. In order to reduce the processing cost of low-pressure tail gas, the method o...

AI Technical Summary

Problems solved by technology

However, when using this method to deal with low-pressure tail gas, on the one hand, it is easy to cause energy waste. On the other hand, the discharge of low-pressure tail gas is often not continuous and constant. When the combustion is not sufficient, carbon monoxide and carbon black will be produced. Carbon monoxide enters the air and affects air quality. Carbon black is easy to fall on the ground under the torch, which has a serious impact on the environment and people's production and life.

[0003] To sum up, there is still no effective solution to the problems of high cost of low-pressure tail gas treatment in the prior art, easy to cause energy waste and environmental pollution

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