Design And Control Of Methyl Acetate Hydrogenation To Ethanol

Fuel ethanol has the advantages of environment-friendly,high octane number and good anti-knock quality,which has been widely concerned.However,the existing methods of producing fuel ethanol restrict the sustainable development of resources,and there is excess capacity of acetic acid in China,so it is a feasible way to produce fuel ethanol from acetic acid derivatives.In this thesis,methyl acetate and hydrogen are used as raw materials to produce ethanol,and the hydrogenation of methyl acetate to ethanol is systematically studied from the aspects of process design,process intensification and plant control.Based on the literature data and thermodynamic analysis,the parameters of the reaction unit are determined.The separation sequence is determined by analyzing the composition and content of the material,and then the basic process of methanol hydrogenation to ethanol containing reaction unit and separation unit is established.Then,taking the total annual cost as the objective,the design parameters of separation unit are optimized by sequential iterative algorithm,and the optimized basic process of methyl acetate hydrogenation to ethanol is obtained.In order to save energy and reduce consumption,dividing wall column（DWC）and extractive dividing wall column（EDWC）are used to strengthen the process.After strengthening,the CO₂ emission,total energy consumption and total annual cost of the process are reduced by 30.2%,30.2%and 16.9%,respectively.Further strengthen the EDWC process,establish the EDWC process with feed preheating and the EDWC process with intermediate reboiler,the results show that the latter has more economic advantages.In order to make full use of the heat of the process streams,pinch technology is used to integrate heat,so that the stream at the bottom of the EDWC and the stream at the inlet of the intermediate reboiler could match to transfer heat.Compared with the process before heat integration,CO₂ emission,total energy consumption and total annual cost are reduced by 16.2%,19.5%and 14.6%,respectively.A plant wide control design method based on integrated framework of simulation and heuristics is used to study the dynamic characteristics of the enhanced methyl acetate hydrogenation process.First,the control schemes of reaction unit and separation unit are established,respectively.Then,the control schemes of each unit are integrated into the whole plant control scheme.Finally,the feed flow disturbance is added to the control scheme.The results show that the purity of each product can return to stable value after disturbance,which also shows that although the hydrogenation process of methyl acetate to ethanol is complex,it still has dynamic controllability.Through the above research,this thesis obtains the process of methyl acetate hydrogenation to ethanol which has advantages in environment,energy consumption and economy,and puts forward the effective control scheme of the whole plant,which provides technical guidance for the industrial application of methyl acetate hydrogenation to ethanol.