A kind of separation and recovery system and method of propylene in the process of producing propylene oxide by hppo method

Abstract

The invention provides a system and method for separating and recovering propylene in the process of producing propylene oxide by an HPPO method. The system includes a rectification tower, a pre-separation tower, a subcooler and a compressor connected in sequence. The present invention improves the propylene separation process in the production process of propylene oxide, and reduces the delivery flow rate of the compressor and changes the feed state of propylene by streamlining and reconnecting the equipment, thereby reducing the operating load of the compressor, The normal operation of the system is guaranteed, and a better separation effect can be achieved at the same time; the present invention reduces the equipment investment by simplifying the equipment and the process, so that the process technology has better economy.

Description

technical field [0001] The invention belongs to the technical field of separation of chemical products, and relates to a separation and recovery system and method of propylene in the process of producing propylene oxide by an HPPO method. Background technique [0002] Propylene oxide is an important chemical raw material and the third largest organic chemical product in propylene derivatives after polypropylene and acrylonitrile. It is widely used in chemical, pharmaceutical, food and textile industries. The traditional industrial production methods of propylene oxide mainly include chlorohydrin method and co-oxidation method. The chlorohydrin method has mature production technology and does not require high purity of raw material propylene, but a large amount of waste water and waste residue will be generated during the production process. It is increasingly severe and cannot meet the requirements of green technology; although the co-oxidation method overcomes the shortcomi...

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Problems solved by technology

CN 1256274 A discloses a process flow for continuous production of propylene oxide by oxidizing propylene with hydrogen peroxide. It adopts a slurry stirring reactor. When carrying out epoxidation reaction, the reaction pressure is low, the temperature is easy to control, and the conversion rate of raw materials and product yield Higher, but there are still many subsequent separation equipment in this process, the process is complicated, and the energy consumption is high

[0004] In the production process of propylene oxide by HPPO method, the separation of propylene is an indispensable operation unit. The conventional process is to first pass through the rectification tower, then pass through the two-stage flash tank, and finally separate again in the pre-separation tower, and the two-stage flash evaporation The top of the tank is equipped with a propylene compressor. Due to the large amount of gas contained in the top of the flash tank, the operating load of the compressor is large, the power consumption is large, and the inlet medium is saturated gas, which is easy to condense into liquid at the inlet of the compressor, which affects the compression. The machine is in normal operation; at the same time, the process flow of the separation unit is complicated, there are many equipments, and the investment is relatively large

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