Process for preparing difluoromethane by gas phase method

Abstract

The invention discloses a process for preparing difluoromethane by a gas phase method, and relates to the field of difluoromethane production processes. The process for preparing the difluoromethane by the gas phase method comprises seven process steps. After the technical scheme is adopted, the beneficial effects of the invention are as follows: the process is suitable for large-scale production;most of HCFC-31 is recovered by a heavy component recovery tower and then returns to the reaction system again to participate in the reaction, so that the unit consumption of dichloromethane is reduced, meanwhile, the HCFC-31 is prevented from being directly discharged into the atmosphere from the tower kettle of a rectifying tower, the problem of environmental pollution is solved, the safety ofthe device is improved, and the economic benefit is remarkable.

Description

technical field [0001] The invention relates to the field of difluoromethane production technology, in particular to a technology for preparing difluoromethane by a gas phase method. Background technique [0002] With the progress of all aspects of society, people's awareness of environmental protection is constantly strengthening. Under the theme of global environmental protection, people pay more attention to the protection of the ozone layer and the reduction of the greenhouse effect while using refrigerants. Therefore, it is extremely urgent to find new environmentally friendly refrigerants that can replace Freon (CFCs). The molecular formula of difluoromethane CH2F2, commonly known as HFC-32 or R-32, is an important component of mixing R410a and R407c. It has a low boiling point (-51.6°C), a large refrigeration coefficient, zero ozone depletion value, and a greenhouse effect. It is a substitute for Freon with excellent thermodynamic performance. As the R410a and R407...

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Problems solved by technology

[0004] The object of the present invention is to aim at the defects and deficiencies of the prior art, and provide a process for preparing difluoromethane by a gas phase method. Most of the HCFC-31 is recovered from the heavy component recovery tower and then returned to the reaction system to participate in the reaction, reducing the difluoromethane The unit consumption of chloromethane also prevents HCFC-31 from being directly discharged into the atmosphere from the rectification tower, which solves the problem of environmental pollution, improves the safety of the device, and has remarkable economic benefits