Process Optimization Study Of Phenol Hydrogenation To Cyclohexanone

Cyclohexanone is an important chemical raw material,which is widely used in chemical industry and other fields.The process of hydrogenation of phenol to cyclohexanone is a green and environmentally friendly route for the efficient production of cyclohexanone,which has broad application prospects.In this paper,the dephenolization of coal gasification wastewater is firstly studied,and the phenol hydrogenation method is used to realize the reuse of phenol to produce cyclohexanone.With the goal of minimizing the total annual cost(TAC),the sequential iteration method is used to optimize the process flow to determine optimum operating parameters,carry out research on energy saving,emission reduction and dynamic control of the above processes,and comprehensively evaluate the processes with TAC,energy consumption,thermodynamic efficiency and environmental impact as indicators.First,the dephenolization of coal gasification wastewater was studied,and a single extractant(n-pentanol)wastewater dephenolization process(CGW-E1)and a coextractant(60% diisopropyl ether + 40% n-pentanol)wastewater dephenolization process(CGW-E2)were proposed.Compared with CGW-E1,CGW-E2 can reduce TAC by 26.65% and energy consumption by 23.71%.Based on the optimal CGW-E2 process,a co-extractant wastewater heat pump process(CGW-HPE2)was proposed.The results show that CGW-HPE2 can recover 3939.51 k W of internal energy in the process,reduce TAC by 11.91%,and reduce harmful gas emissions by 13.44%.The reuse of phenol was realized by the process of hydrogenation of phenol to cyclohexanone.In order to solve the separation difficulty of azeotropic and near-boiling systems in the reaction product,diethylene glycol was determined as the organic extractant based on relative volatility.Based on COSMO-The SAC model identified1,3-dimethylimidazole dimethyl phosphate([DMIM][DMP])as the ionic liquid extractant,and proposed a phenol hydrogenation process(ED)based on an organic extractant and a phenol hydrogenation process(IL-ED)based on an ionic liquid extractant.Compared with ED,IL-ED can reduce TAC by 23.43%,energy consumption by 31.72%,and harmful gas emission by 31.71%.Based on the optimal IL-ED process,a heat pump process for hydrogenation of phenol to cyclohexanone based on ionic liquid extractant(IL-HPED)was proposed.The results show that IL-HPED can recover178.65 k W of internal energy in the process flow,and has a good effect in reducing energy consumption and reducing harmful gas emissions.In order to respond to the country’s call for promoting clean energy and realizing energy conservation and emission reduction,energy-saving and emission-reduction research on the above-mentioned process is carried out through thermal integration technology and solar organic Rankine cycle technology(SORC),the CGW-HPE2 process based on thermal integration and SORC and the IL-HPED process based on thermal integration and SORC are proposed.After applying thermal integration and SORC,the TAC of the above two processes was reduced by 3.49% and 15.43%,respectively,the energy consumption was reduced by 8.72%,34.82%,and the harmful gas emissions were reduced by 7.48% and 39.54%,respectively.The results show that heat integration technology and SORC have a good performance in energy saving and emission reduction.Finally,the dynamic control research was carried out on the dephenolization process of coal gasification wastewater and the process of phenol hydrogenation to cyclohexanone.A temperature control scheme based on a fixed reflux ratio is proposed.After introducing ±10% feed flow disturbance and ±5% feed composition disturbance,the stable operation of the device can be effectively guaranteed for the CGW-E2 process;for the IL-ED process,the main Product purity is well controlled.The above study shows that the coal gasification wastewater dephenolization and phenol hydrogenation to cyclohexanone processes proposed in this paper can provide some reference value for related industrial production,and the heat pump technology,heat integration technology and solar organic Rankine cycle technology are effective means to save energy and reduce emissions.