Study On Technology Simulation And Improvement For FCCU Main Fractionator And Absorption-stabilization System

Fluid catalytic cracking (FCC) process is an important process in secondaryprocessing in oil refining industry in which it plays a very important part. But mainfractionator system and absorption-stabilization system are faced with severalproblems, such as extending production quantity, improving product quality andsaving energy. In this paper, software PRO/â…¡is adopted to simulate the whole flowthat is main fractionator system and absorption-stabilization system. According to theflow's feature, the new saving-energy technology should be developed in order tosettle previous problems and obtain better economic benefit.For absorption-stabilization system, a new energy-saving technology namedsecond condensation and another technology combined second condensation andintermediate reboiler are proposed. By software PRO/â…¡simulation of the newtechnologies and the conventional two-tower technologies, it is shown that the newones share the character of the two-tower process with double feeding, and reduce thecold load before the surge tanks. Compared with the cold load before the surge tanksof cold feeding process, that of second condensation technology and the combinativetechnology decreases respectively by 57.8% and 40.5%. The new technologies reducethe energy consumption, the flux of desorption gas and the load in desorber.Considering stabilizer of absorption-stabilization system, a new technology namedside-draw production is developed. The results of simulation are listed as follows.The quality of additional absorbent improves and the absorption effect also improves.Distillation curve of stable gasoline of the new technology tallies with that of theconventional technology and the quality can meet the challenge. Moreover, the newone can reduce the load in absorber and desorber and save the energy consumption.By software PRO/ â…¡ simulation of the intermediate reboiler technology ofabsorption-stabilization system for certain petrochemical corporation, the simulatingresults tally with practicable data. The intermediate reboiler technology can reducethe load of the reboiler in the bottom of desorber. The C3+ composition percent indesorption gas is low and the intermediate heat-exchange is unwanted. The improvedtechnology shares the character of the two-tower process with cold feeding and heatfeeding. And the preliminary estimation of the economic returns is good.The relevance of FCCU main fractionator and absorption-stabilization system isgreat. According to this character, the simulating technology of the whole flow isrealized in this thesis and modifies the previous idea of researching the two systemsindependently. The different side-draw production technologies are adopted for mainfractionator. By choosing I/O algorithm, the side tower and the main tower can becalculated synchronously. And the effect of the whole flow simulation is very good.