Parallel Atmosphere-vacuum Distillation Process Simulation And The Coupling And Optimization Of Heat Exchanger Networks

Atmosphere-vacuum distillation unit (AVDU) is the first step of petroleum processing. These stage of process consumes a lot of energy in the petrochemical industry, which occupies about 20% of entire energy consumption in a crude oil refinery. The design level of the heat exchanger network (HEN) is very important to the energy recovery of AVDU. This dissertation probed China Offshore Bitumen CO.,LTD's three sets of AVDUs with process simulation.Optimization of the HENs and coupling of the HENs of 3 AVDUs were also included in the research.Published literatures generally tended to isolate the optimization of the HENs from the process simulation,while in this paper,the basic datas of HENs were acquired from the simulation of AVDU,and then, the HENs were optimized with pinch design method(PDM). The whole work is described as follow:First, Pro/II with Provision was harnessed as the process simulation engine. Sequential modular was applied on flash column, prefractionator,atmospheric column and vacuum column for steady state simulation. According to the true boiling points(TBP) data, crude oil was divided into several pseudo components which were the input of flash column or the prefractionator. Suitable thermodynamics model, module unit and algorithm were selected, and process parameters were regulated simultaneously. At last, process simulation of three set of AVDU were done separately. The process simulation results showed good agreement with the on-site data. These results from process simulation provide firm foundation for the optimization of HEN.Secondly, since the HENs in this refinery were relative backward, Hx-net was employed in this paper to separately optimize 3 HENs with PDM.The results showed that the effect of energy saving was remarkable. In the process of HEN's optimization, It is found that the interconnection among HENs of several different sets of AVDUs were scarcely reported by published literatures. Through this work of HEN Optimization, an attempt was made on dealing with paralleled AVDUs' integrated optimization of process and HENs.The results indicated that the least revamp under the direction of the optimization would bring greater economic benefits.