The problems of an energy-saving and high pollution in the Russian Federation is a hot topic since the country step-up to a market economy. The existing facilities of process industries were mainly designed and built-in time of cheap energy resources. The main priority was to get the final product and supply as much energy as was required by the technology. The situation was not so much changed the last 3 decades and the energy efficiency gap in the Russian process industry is still high. Nowadays, this issue is becoming more complex accounting for global environmental problems, such as different kinds of wastes and global warming. The chemical industry is one of the most energy-intensive production sectors that generate a huge amount of solid, liquid and gaseous wastes. The last trend of sustainable development out to develop both new processes and retrofit in a new way addressing sustainability and green economy. One of the most beneficial approaches for retrofit of reprocessing industries is a Process Integration. This method was unified for application in process system engineering. However, the real application requires a detailed investigation of the process flow diagram (PFD), process simulation and development of local methods to tune-up the general methodology to particular case studies.
In this work, the analysis of calcium chloride production was analysed to identify the energy gap and provide the retrofit roadmap. The initial concentration of calcium chloride in raw materials is 14% (mass) and it has to be concentrated up to 35 % (mass). Process Integration techniques were used for the analysis of the existing process to identify the bottlenecks and disadvantages of existing PFD and operation modes. Pinch approach was applied to get real energy targets, the energy gap of an existing process and prospective options of process update. The authors proposed the solution for process improvement by use of detailed simulation of heat exchanger parameters and systematic synthesis heat exchanger network to get a feasible and economically viable retrofit option. The case study of the Russian chemical industry was described and analysed. There are some process constraints, e.g. limited performance of existing equipment, that out to develop a local methodology to solve the problem in an appropriate and most profitable way. It was defined that the real energy consumption of existing process is 25% higher than the target value. Nevertheless, the 1st feasible retrofit case with a detailed simulation of heat exchanger network parameters reduces the energy consumption only by 17 % but, at the same time, the improved operating conditions of evaporation unit were achieved. The 2nd retrofit option reduces the energy consumption by 22% and more complicated network with additional operation issues was designed. The process flowsheets of both retrofit options were proposed and economic indicators were calculated. They provide information for investors and decision-makers on possible options for energy and emission reduction and profitability improvement. The results of this work may be used for efficient retrofit of industrial evaporation units in different process industries to reduce their environmental impact and green economy transition.
|Position of speaker||Senior Researcher|
|Publication||Journal of Cleaner Production|
|Affiliation of speaker||Tomsk Polytechnic University|