Study On Extraction Of Phenol From Coking Gasoline And Process Simulation And Energy Saving Of Crude Phenol Refining

China is rich in coal tar resources,and the comprehensive utilization of coal tar is very important.The coking gasoline obtained from coal tar by delayed coking which contains about 30%phenolic compounds.The existence of phenolic compounds will have an adversely effect on the subsequent hydrogenation and upgrading process of coking gasoline.Meanwhile,these phenolic compounds are important chemical raw materials,so it is essential to extract phenol from coking gasoline.There are many methods to extract phenolic compounds from coal tar,and the main method in industry is chemical method.However,it requires the use of a large number of strong acids and alkali,which will cause great corrosion inside the equipment and a large amount of phenol-containing wastewater will be produced.In order to avoid the above problems,an extraction method was adopted to extract phenolic compounds in coking gasoline,and ethylamine solution,which is easy for recycling was chosen as an extractant,and a new process for extractant recovery was put forward,which was different from the conventional distillation column.The amine phenol liquid fed at the top of the tower is distilled out of only ethylamine gas through a recovery tower without a condenser,and then it is absorbed by the phenol-containing aqueous solution in the process to obtain a recycled ethylamine solution extractant.This new process not only has high extraction rate of phenolic compounds in coking gasoline,but also has high recovery rate of extractant,low energy consumption,and has good economic and ecological benefits.The main research contents of this article are summarized as follows:1)The experiment for the extraction of phenolic compounds in coking gasoline with ethylamine was conducted through a small laboratory test device.The results show that the extraction rate of phenolic compounds from coker gasoline was 92.19%at normal temperature and pressure with 25%fresh ethylamine 3:1 continuous countercurrent extraction.2)Establish the model components through Aspen Plus software,choose the NRTL method as the physical property method,and simulate the process of 25%ethylamine 3:1 continuous countercurrent extraction of coking gasoline to verify the accuracy of the model.Then use Aspen Plus software to simulate the ethylamine extraction of phenolic compounds in coking gasoline and the recovery process,and optimize the process parameters.Under the optimal operating conditions:The extraction rate of phenol in extraction tower is 98.06%,the recovery rate of ethylamine in recovery tower is 99.99%,the washing rate of amine in washing tower is 99.99%,and the absorption rate of ethylamine in absorption tower is 99.99%.3)Using Aspen Plus software to simulate the conventional distillation and separation process of crude phenol,and using the NQ curve to optimize each column,and the optimization results of each column were determined.The Aspen Plus software was used to conduct energy-saving research on the conventional distillation and separation process of crude phenol.The intermediate reboiler was set up in the dehydrating tower and the interpara-cresol tower,and the phenol tower was simulated by heat pump rectification.4)Using Aspen Energy Analyzer energy analysis software to optimize the design of heat exchange network of the processing of extracting phenol in coke gasoline and refining process of crude phenol.With the goal of minimizing the total annual cost,determine the optimalΔT_minwas 10℃,and finally optimize the determined heat exchange network.As a result,the load of cold public works was reduced by 27.46%,and the load of hot public works was reduced by 25.82%.