Preparation Of Bio-oil By Catalyzed Hydrothermal Liquefaction On Penicillin Residue In Ethanol-water Reaction System

Penicillin residue is a kind of organic hazardous waste that threatens the environment and human health.Hydrothermal liquefication(HTL)can transform penicillin residue into clean energy.The ethanol-water mixed solvent of HTL can take advantage of the synergistic effect between ethanol and water to simultaneously improve the yield and quality of bio-oil.Based on the analysis of the influence of the ethanol-water mixed solvent system on the HTL of penicillin residue,the optimum process parameters were determined and the main reaction path of bio-oil formation was clarified.The HTL of penicillin residue was catalyzed by adding molecular sieve and modified molecular sieve catalysts,and the catalytic mechanism was clarified.On these basis,the quality of bio-oil was further improved by stepwise two-step catalytic reaction.Under the ethanol-water mixed solvent system,the optimal process parameters of HTL of penicillin residue were determined as follows:ethanol-water ratio of 1:1/reaction temperature of 280?/residence time of 150min/solid-liquid ratio of 15%.Under these conditions,the highest yield of bio-oil was up to 33.29wt%,and the bio-oil was mainly composed of hydrocarbons containing nitrogen and esters.The esters in bio-oil were mainly formed by the esterification reaction between ethanol or other heteros and carboxylic acids.Hydrocarbons mainly came from the deacidification reaction of fatty acids and ring-opening formation of aromatic family substances.Nitrogenous materials were derived from the dehydration condensation of ammonia and fatty acids,the decarboxylation of amino acids and the Mail lard reaction of proteins and sugars.Four molecular sieve catalysts(HZSM-5,MCM-41,?-Al2O3,and ?)could reach the highest bio-oil yield when their addition amounts were 15%.The quality of bio-oil was improved after the catalysis reaction.The analysis of water phase products showed that existence of valuable nutrients(N-NH3,TOC,and TN).In addition,the reusability of four molecular sieve catalysts was studied.Four kinds of molecular sieves were modified by adding transition metals(Fe,Cu,and Co).The effect of mono-metal modified molecular sieves was better than that of polymetal modified molecular sieves,and the addition of catalyst could improve the highest H content in bio-oil up to 10.46%,and the highest HHV was 40.29 MJ/kg.In addition,in the mono-metal modified molecular sieves,Fe showed a good hydrogenation effect,and Cu showed a good denitrification effect.Stepwise ectopic catalysis could significantly improve the quality of bio-oil compared with in-situ catalysis,and stepwise two-step catalysis could further improve the quality of bio-oil.After secondary catalysis,the content of hydrocarbons in bio-oil increased to 8.72%,the nitrogen content decreased to 9.66%,the proportion of short-chain light oil reached 3.69%,and the coking rate decreased to 2.44%.On these basis,the two-step catalytic mechanisms for improving quality of bio-oil turned out to be Cu removing nitrogen through oxidation,Fe hydrogenating through lewis acid site transfer.This study provided a certain theoretical basis and potential technical support for the realization of harmless resource disposal of penicillin residue.