Method and device used for preventing cavitation of chilling water pump in process of preparing propylene from coal-based methanol

Abstract

The invention provides a method and device used for preventing cavitation of a chilling water pump in a process of preparing propylene from coal-based methanol. The method comprises the following measures that: an anti-eddy baffle is respectively arranged at the bottom process water outlet of each of a prechilling tower and a chilling tower; and the bottoms of collector downcomers arranged in the prechilling tower and the chilling tower are slightly lower than a water / heavy hydrocarbon interface, the collector downcomers are provided with baffles used for sealing the bottom outlets, and the inner sides of the lower parts of the collector downcomers are provided with grooves. By using the method and the device provided by the invention, the problem of cavitation of the chilling pump in the process of preparing propylene from coal-based methanol can be solved, so that a chilling system can operate stably.

Description

technical field [0001] The invention relates to a process for producing propylene from coal-based methanol, more specifically, a method and device for preventing cavitation of chilled water pumps in the process of producing propylene from coal-based methanol. Background technique [0002] The world's first coal-based propylene plant with an annual output of 500,000 tons is the first attempt at the industrial application of methanol-to-propylene (MTP) process technology. During the operation of the MTP unit, the problem of oil-water separation has always been the bottleneck that plagues the smooth operation of the unit. Oil-water separation mainly involves quenching towers and pre-chilling towers, oxide extraction towers and extraction towers. Among them, the oil-water separation problem of the quenching tower and the pre-chilling tower is the most worthy of attention. Insufficient oil-water separation in the quench tower may cause oil cavitation at the inlet of the quench ...

AI Technical Summary

Problems solved by technology

During the operation of the MTP unit, the problem of oil-water separation has always been the bottleneck that plagues the smooth operation of the unit

The poor oil-water separation effect of the quenching tower may cause oil cavitation and tripping at the inlet of the quenching water pump, which in turn leads to high inlet temperature of the hydrocarbon compressor and tripping accidents

[0003] The process design of the chilling system does not take into account the actual production needs. For the analysis of the cavitation problem of the chilling water pump in the chilling system, there are two main reasons: 1) When the liquid medium enters the nozzle, it swirls to form a vortex, and the turbulence and vortex formed The flow may bring unfavorable factors such as pipeline vibration, vortex brings air bubbles, causes cavitation, and reduces pump performance; Injection into the inlet pipeline of the cold water pump will cause cavitation of the pump, which may cause fluctuations in the entire device or even shutdown accidents

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