Energy Optimization Of Molasses Alcohol Production Process Based On Process Simulation

With the reform of China’s energy strategies,bio-energy,represented by bio-fuel ethanol,has received extensive attention again as a national strategic emerging industry.September 2017 National Development and Reform Commission proposed to promote the use of automotive ethanol gasoline nationwide,the basic implementation of full coverage to 2020.The production of biofuel ethanol in China in 2016 was about 2.6 million tons,which meets the use of northeast,Henan,Anhui and Guangxi provinces.If the automotive ethanol gasoline in the country to promote the full use of ethanol per year,demand of ethanol will increase to 10 million tons.Then,this huge gap of domestic ethanol production brings new impetus to the development of alcohol industry in China.Aiming at the problem of high energy consumption in the process of domestic molasses alcohol production,this paper made use of process simulation technology to analyze the system with actual production technology,and put forward some improvement measures to provide reference for actual production.Firstly,using ASPEN PLUS software to simulate the actual production process,the ethanol flow rate of the finished product simulated with NRTL physical method was 2500 kg/h,the mass fraction was 92.2%,and the relative error of the actual production was 0.6%;the quality fraction of industrial alcohol in distillation tower was 94.8%,Compared with the actual production,the relative error was 0.2%,the hammer degree of the four-effect evaporation concentrated liquid was 70 °Bx,and the relative error was 1.4%.Both the simulation results and the actual production were within the allowable range of production error,which satisfies the actual production requirement,and also verified the applicability of the process model and the selected NRTL physical property method to the research system.Based on the process simulation results,the energy utilization situation in the production process was analyzed,the energy utilization weak link was found,the single section optimization and the System Energy integration optimization were proposed,and three kinds of different process improvement schemes were put forward.The exergy lose efficiency of three process improvement schemes were as follows: The system exergy lose efficiency of single section optimization scheme increases by 9.95% to 25.75%,and the exergy lose efficiency of system optimization scheme one increases by 12.53%,and increases to 28.15%.The exergy lose efficiency of the system optimization Scheme II increased by 43.54% to 83.84%.Three kinds of technological schemes save economic benefits of 6.1784 million yuan/year,6.0984 million yuan/year,9.4024 million yuan/year respectively.According to the results of analysis of three kinds and the actual production conditions,the process of indirect heating and direct heating of the distillation column in the crude distillation column and the discharge aldehyde tower were determined,namely the optimal scheme of the system optimization scheme with the largest energy utilization and the highest economic benefit.According to the engineering application research of the best technological scheme,the cost of the new investment is 3.66 million yuan,the investment payback period is 2.44 years,which verified the good yield and the feasibility of the process.The improved process reduces the consumption of production,improved the energy utilization rate,improved the economic benefit of the enterprise,created the income for the society,and was beneficial to the sustainable development of the enterprise.