Process optimization of the first set of fluidized bed methanol to propylene plant

Abstract

In order to successfully complete the commissioning of the first industrial demonstration unit of methanol to propylene FMTP in fluidized bed, through the investigation and technical exchange of similar enterprises using methanol to olefin (DMTO) technology of Dalian Chemical Institute, methanol to olefin (SMTO) technology of Sinopec, methanol to olefin (SHMTO) technology of Shenhua Group and methanol to propylene technology (MTP) in China, through the comparison and analysis with FMTP process technology, it was found that there were deficiencies in the design of the catalyst recovery system of the original FMTP unit, the catalyst circulation pipeline between the three units, the heat transfer system of washing water, the waste heat recovery system and the reactor measurement instrument system. According to the construction and operation experience of the same industry, the waste catalyst recovery system was designed and transformed into a bucket recovery system. The catalyst circulating pipeline was optimized to be a lifting pipe and a flange tube cap, the xylene cleaning system was optimized to be in the washing water heat exchanger, the steam automatic ash blowing system was optimized to be in the waste heat recovery equipment, and reactor instrument back blower system was optimized to be in the reactor measuring instrument. After the above process optimization, the content of combustible gas in the analytical gas of the catalyst recovery system was significantly reduced, and the catalyst was prevented from sticking together; the catalyst circulation pipelines of the three reactors were designed the lifting tube, the buffer tube and tube cap were designed at the top of the lifting tube; the catalyst circulation between the three reactors was smooth during the operation of the plant, the parameters of the catalyst circulation, the temperature of the tube, the density of the tube and the pressure of the tube in the reactor were close to and reached the design indicators; start the xylene cleaning system to wash the blocked heat exchanger, and the heat exchanger cleaning effect is obvious; after the automatic steam ash blowing system is put into operation, the efficiency of waste heat recovery system is significantly improved; the inert gas of reactor instrument back blower system was optimized to process gas, avoid the influence of inert gas on the downstream separation unit. In the four commissioning runs of FMTP device, the above system runs smoothly, it lays the foundation for the long cycle safe and stable operation of the plant.

Keywords

• fluidized bed
• methanol
• olefin
• fmtp