Simultaneous improvement in qualities of bio-oil and syngas from catalytic pyrolysis of rice husk by demineralization

Abstract

This study aims to investigate the influences of different demineralization pretreatment processes on the properties of liquid and gas products from catalytic pyrolysis via activated carbon catalyst. To achieve this goal, deionized water, hydrochloric acid, and acetic acid were used to remove ash. The results indicated that leaching could remove a large amount of alkali and alkaline earth metals (AAEMs). Besides, the experiments of different leaching solutions on catalytic fast pyrolysis of rice husks were conducted. It can be found that compared with direct pyrolysis, the catalytic pyrolysis produced more gas products, in which CO increased by 6.49%, while the bio-oil was concentrated in phenols (more than 90%). After demineralization, the content of CO in gas products further increased by 8.04%, while the relative content of phenol in bio-oil enhanced by 14.79% as well. Catalysis can enrich phenol in bio-oil, and leaching can enhance this enrichment. Meanwhile, demineralization can further improve the quality of syngas. The sample after demineralization by hydrochloric acid performed best on catalytic fast pyrolysis, where CO accounts for 57.68% volume of gaseous product and phenol accounted for 68.21% of bio-oil.