Pyrolysis Of Corn Oil Spent Bleaching Clay To Produce Bio-Oil And Utilization Of Solid Residue

China has a large oil and fat industry system and consumer population,with the annual expansion of the edible oil processing industry,the amount of spent bleaching clay,a by-product of oil refining process,also increases sharply.The spent bleaching clay is abundant in quantity and low cost,with the dual properties of"waste"and"resource",and has great potential for recycling and application.If spent bleaching clay can be used rationally,it can not only reduce the cost of the edible oil processing industry,but also reduce environmental pollution and help the country achieve the goal of carbon neutrality.How to properly handle and resourcefully utilize the spent bleaching clay and turn it into a treasure has become an urgent problem to be solved.In this paper,aromatic-rich bio-oil was prepared by microwave and electric heating catalytic pyrolysis experiments with corn oil spent bleaching clay as the object of study,and the microwave process parameters were adjusted.Then the spent bleaching clay-based foam ceramic materials were produced by organic foam impregnation of the pyrolysis residue.In view of the advantages of high temperature and low pressure drop of the spent bleaching clay-based foam ceramic,a new foam catalyst was produced by impregnation with ZSM-5 molecular sieve on its surface and applied to the continuous catalytic pyrolysis system of clay oil to improve the catalyst efficiency and bio-oil quality.Based on the above process,the whole component utilization of spent bleaching clay was achieved.The details are as follows:(1)In the pyrolysis of spent bleaching clay,the pyrolysis temperature range(300℃to 600℃)of corn oil spent bleaching clay was studied by TG-DTG analysis method,and the activation energy calculated by KAS method and FWO method was110.64 k J/mol and 115.80 k J/mol,respectively.The experimental results of microwave heating and electric heating showed that microwave heating can save 50%reaction time and 53.0%,39.8%and 47.3%energy consumption compared with electric heating under the three conditions of non-catalysis,in-situ catalysis and ex-situ catalysis,respectively.Microwave heating increased the relative content of aromatics by promoting hydrogen transfer and cyclization reactions.In addition,the optimal pyrolysis temperature,catalytic temperature,mass ratio of feedstock to catalyst and nitrogen flow rate were obtained as 500℃,500℃,10/1 and 50 m L/min,respectively.Under these conditions,the relative content of aromatics was 87.89%,of which monocyclic aromatic hydrocarbons was up to 71.20%.(2)In the pyrolysis residue preparation of ceramic foam and foam catalyst,by adding alumina,magnesium oxide and other additives,the spent bleaching clay-based ceramic foam was prepared by the organic foam impregnation method.When the amount of alumina was 25 wt.%,the spent bleaching clay-based ceramic foam with yellow-green,three-dimensional pore structure and moderate hardness could be prepared.In addition,its rough surface was conducive to catalyst attachment.The ZSM-5/spent bleaching clay-based foam catalyst was prepared by impregnating ZSM-5.The characterization analysis showed that the ZSM-5 powder could be uniformly loaded on the spent bleaching clay-based foam ceramic.Compared with ZSM-5powder,the specific surface area of the catalyst after loading decreased by 33.378 m~2/g,but the pore volume and average pore diameter increased by 1.565 cm~3/g and 0.099nm,respectively.(3)In the pyrolysis of clay oil by ZSM-5/spent bleaching clay-based foam catalyst,the pore size wolud affect the packing density of ZSM-5 on the catalyst support carrier.Low packing density was conducive to reducing the diffusion limit and shortening the diffusion path,thereby increasing the aromatics content in the bio-oil.The experimental results showed that the relative content of monocyclic aromatic hydrocarbons increased by 39.81%under 5ZFC catalysis compared with ZSM-5 powder catalysis.In addition,the continuous microwave pyrolysis of the clay oil showed that the ZSM-5/spent bleaching clay-based foam catalyst had higher initial activity and obtained higher aromatics content compared to powdered ZSM-5.In addition,the loading rate affected the activity release rate of the catalyst in the pyrolysis process.The lower the loading rate,the faster the activity release rate and the faster the deactivation rate,but the higher the aromatics content can be obtained by improving the catalyst utilization rate.