Process Optimization Of The Continuous Reforming Unit

The150×104t/a Continuous Catalyst Reforming unit is the key project of a Dalian petrochemical refinery in "Twelfth Five Year Plan". The project adopts Continuous Reforming process package of Axens company, the original engineering design is carried out by the Sinopec Engineering Incorporation (SEI)Firstly, the necessity of Continuous Catalyst Reforming project construction is analyzed. Then the suitability that the Process of Axens’ continuous reforming was selected is demonstrated by contrast. And the process is briefly described.Then, this paper puts forward the following three design optimizations on the basis of the original design. Through the methods of the heat check calculation on material balance, energy consumption comparison and so on, using Aspen software, gets the conclusion that the optimizations can reduce investment, the occupation of land and save energy, meanwhile the system can be more safety and operate more conveniently. There are three process optimizations in this paper.To combine the xylene fractionator with dehexanizer and deheptanizer by heat integration. The high temperature top gas of xylene fractionator is used as the bottom heat sources of dehexanizer and deheptanizer. The cooling source of xylene fractionator top gas is saved on the one hand, and the heat sources of dehexanizer and deheptanizer’s bottoms are saved on the other hand, so as to achieve the purpose of saving the energy.The depentanizer’s reboiler is replaced by a high heat flux tube exchanger with steam heating. Although the one-time investment and energy consumption are similar, but it greatly reduces the occupied area, reduces the difficulty of construction and installation, provides convenience for field operator’s operation, and increases the safety of the unit.The steam and condensate water process flow of the unit are redesigned. The condensate is flashed step by step to more lower pressure, so the low grade steam can be recovered, and at the same time reduce the possibility of "water hammer" on the condensed water lines. The condensate is used as hot water for tracing and as boiler feed water. The effect of energy saving is outstanding.