| With the continuous development of social economy and the worsening of human living environment, people are paying more and more attention to the energy problems and environmental problems. Meanwhile, environment problems is closely related to energy problems, because there are many environmental problems caused by the irrational energy utilization. In order to solve these, energy conservation and emission reduction has proved to be the most effective way except to find new energy resources. In our daily lives, many products are originate from oil which makes the petroleum and chemical industry to be one of the major energy-consuming area. Oil is a nonrenewable resource consumed quickly, and the emissions of greenhouse gases in refinery also caused a great pressure on global warming. Compared with developed countries, there is great disparity in the aspects of efficiency, emission and cost for domestic refineries. The crude oil distillation is the first process of the petroleum refinery which consume large amount of energy. It has important significance for domestic petrochemical industry to make a process in system optimization, investigating energy conservation and emissions reduction of crude oil distillation process.In order to achieve these goals, we selected the advanced energy-saving technology called self-heat recuperation technology(SHRT) which is developed in recent years by professor Kansha from University of Tokyo. The characteristic of this technology is that the whole-process heat is recirculated within the process without external heat added, leading to large energy savings by useing compressor and heat exchanger. The feature of SHRT is very suitable for crude oil distillation process. The research on the practical application of SHRT in crude distillation process is valuable for process design in new refineries.The main content of this thesis is as follows:First part is the description of the SHRT prototype, then use two method: the traditional method of exergy analysis and new methods of entransy analysis to reflect the performace of this technology. By comparing the differences between the two analysis methods, make a deep understanding of the energy saving mechanism by SHRT is irreversible decreasing.Second part is a brief description of crude oil distillation process. A conventional crude oil distillation model is presented as the basis of the reconstruction to be used. Then according to the real refinery sit uation, a heat-recovery crude oil distillation model is established as contrast. Finally, since conventional crude oil distillation model is too complex to apply SHRT, the conventional model is splited into two major modules which are preflash column module and atomosphere distillation column module. and the atmosphere column is also splited into four simple consequent series along the side strippers. Then SHRT is applied to each module independently.Thirdly, the minimum pressure ratios required in each self-heat recuperated crude oil distillation modules are determined. The simulation results of three different processes were analyzed. The results show that the SHRT achieved about 83% and 69% reduction in energy consumption compared with the conventional and heat-recovery crude oil distillation processn, even taking the power generation efficiency into account, SHRT can also achieve nearly 10 and 2 million tons of standard coal savings annually, leading to large amount of CO2 emissions reduction. Then some sensitivity analysis is made, such as the impact of the minimum temperature difference, entropy efficiency of compressors to the whole process. Final part is the economic analysis of self-heat recuperated crude oil distillation process, it was found that the investment of the compressor is very high along with a high maintenance costs, although fuel savings leading a reduction in operation costs, but by taking the payback period of a refinery into account, detailed feasibility studies is still needed befor SHRT used in a real refinery. |
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