The Simulation And Energy-saving Research Of Continuous Catalytic Reforming Unit

Continuous catalytic reforming (CCR) unit is one of the major petroleumprocessing processes, because of the trait of its process flow and the chemical featureof the reforming reaction, CCR has become one of the units in the petroleum refinerywhich consume the most energy. It seriously affects the energy-consumption conditionof the whole refinery. Thus it is very necessary to take steps to reduce theenergy-consumption of this unit. Although extensive researches have been done, theyare mostly limited to a single unit or device, and the overall optimization andintegration are not sufficient, therefore no significant progress shown in energyconsumption. In this paper, rigorous simulation of a CCR unit was made. Based on thesteam data extracted from the whole process, utilizing pinch technology, theoptimization of the heat exchanger network and the heat integration between rectifyingtowers and the process system were completed. Therefore, this work has importantpractical value and significance.Rigorous simulation of a CCR unit was made with Aspen Plus. According to thedistillation range, the raw oil was divided into several pseudo components as thefeeding of the unit. Thermodynamics method, module units and convergent methodwere selected suitably, and process parameters were regulated simultaneously, at lastthe process simulation was finished. The results of the simulation agreed well with theoperating data. Moreover, the unit operation model and thermodynamic model usedhere had been proved accurately and reliably to simulate this system. So the simulationcould provide correct data basis to the energy-saving reach of the unit.According to the results of the simulation, stream data was extracted. Withoutchanging the technical process, the energy-consumption of the heat exchanger networkwas studied using pinch technology. Respectively based on the original heat exchangernetwork and the network with the maximum energy recovery, two energy-savingschemes was proposed. In the first scheme, compared with the orginal network, theamount of hot and cold utilities had reduced15.4%and25.1%respectively; theamount of hot and cold utilities of the second scheme had reduced19.7%and32.0%.The research of energy integration of the unit was done, the integration between the rectifying towers and the process system was carried out. Similar to the Part2,finally two energy-saving schemes were proposed. In the third scheme, compared withthe orginal network, the amount of hot and cold utilities had reduced20.3%and33.2%respectively; the amount of hot and cold utilities of the fourth scheme had reduced23.8%and38.9%.By comparing economic benefit of the four schemes, the scheme which saved themost operating cost and took the shortest payback period was the fourth one. Theoperating cost saved by this scheme was19,630,000RMB／year and we could expecta payback within0.61year. The fourth scheme was intended to be best one.