Influences Of Protein And Lipid Contents Of Feedstocks On Hydrothermal Liquefaction And Biocrude Oil Upgradation

The conversion efficiency of biomass hydrothermal liquefaction(HTL)depends on various parameters,including reaction temperature,residence time,composition and catalyst.The composition of the biocrude oil was mainly affected by the components of the feedstocks,i.e.,protein,carbohydrates and lipids.There are obvious differences in the components of the biocrude oil produced from different feedstocks.The biocrude oil contains high oxygen and nitrogen contents,and is inferior in quality to the petroleum.The biocrude oil yield,quality and the migration and distribution of protein during hydrothermal liquefaction process were mainly affected by the reaction temperature.The purpose of this research was to improve the utilization rate of feedstock and increase the conversion efficiency for high quality biocrude oil.In this study,two types of feedstock with different raw fat and protein contents were selected for hydrothermal liquefaction to evaluate the influence of fat and protein on biocrude oil yield and quality.The biocrude oil was then refined and upgraded using catalysts.The effects of reaction temperature,reaction time,solid content of feedstocks and catalyst on the yields of the HTL products were also studied.The experimental results showed that the influence orders of the parameters were:reaction temperature>reaction time>solid-content.The conversion rate was 55%from low-fat and high-protein feedstock obtained at 260℃,60 min reaction time and solid-content of 25%.While for high-fat and low-protein feedstock,the highest conversion rate was 82.9%obtained at 220℃,90 min reaction time and solid content of 20%.However,the condition for the best biocrude quality was not consistent with that for the highest biocrude yield.Rresults indicated that the content of hydrocarbons in biocrude oil from low-fat high-protein feedstock was higher than that of high-fat and low-protein raw materials.With the increase of reaction temperature,the conversion rate of biocrude decreased while the quality increased.In this dissertation,the effects of reaction temperature,reaction time and the solid content of raw materials on the process of hydrothermal liquefaction were investigated using FeZSM-5 catalyst.The results illustrated that the yield of biocrude was 19%achieved under supercritical conditions at 410℃,28 MPa of process pressure,60 min of reaction time,and 25%of solid content.With the increase of the reaction temperature,the contents of organic carbon and nitrogen in the water phase was increased.It was shown that the application of catalyst effectively improved the efficiency of biomass liquefaction reaction and enhanced the carbon recovery in the oil phase and the nitrogen recovery in the water phase.In order to avoid the loss of organic carbon in the raw materials and utilize the biomass effectively,firstly,the biocrude oil(maximum yield of 55%)was obtained at 260℃ with an initial pressure of 2 MPa,and then the biocrude oil was refined using the upgrading technology.The experimental results showed that the combination method of hydrothermal liquefaction and thermal cracking was very effective to improve the oil yield and quality of biocrude from low-fat and high-protein feedstock.When the reaction temperature was 320℃ and the reaction time was 3 hours,the maximum yield of upgraded oil was 81.3%with a higher heating value(HHV)of 40.80 MJ/Kg,and the energy recovery was above 80%.Hydrothermal liquefaction and catalytic upgrading experiments of high-fat and low-protein food processing waste were used to explore new method for the selection of feedstock for commercial HTL application.The HHVs of the upgrading oil from such waste were very high.A HHV of 41.52 MJ/kg was obtained from the biocrude oil produced at 320℃ with a retention time of 3 h,which was the same HHV as of the petroleum(41 MJ/kg).The low protein content of the feedstock led to a low nitrogen content of the biocrude oil.The content of nitrogen in the biocrude oil after upgrading was 0.39%from biocrude obtained at 320℃ with a retention time of 180 min,and the biocrude oil yield of 78.6%.As an important step in commercization of HTL,the upgrading process could improve the biocrude production and increase the energy density simultaneously.The results showed that the combination of hydrothermal liquefaction and catalytic upgrading could effectively improve the utilization of raw materials and the quality of biocrude oil.