{"title":"Removal of ash in biochar from carbonization by CO2-enhanced water leaching and its mechanism","authors":"Shuo ZHANG, Yan-peng BAN, Yu-xin WEN, Jia-long ZHU, Yi-ming WANG, Hao-quan HU, Li-jun JIN","doi":"10.1016/S1872-5813(22)60059-8","DOIUrl":null,"url":null,"abstract":"<div><p>Ash content is an important factor affecting the quality and combustion performance of biochar. In this paper, a method of ash removal from biomass is proposed by carbonization followed by CO<sub>2</sub>-enhanced water leaching. The effects of the carbonization temperature of bagasse, the temperature and time of CO<sub>2</sub>-enhanced water leaching on the deashing were investigated. The results show that the deashing rate firstly increases and then decreases with the carbonization temperature, while the opposite trend is obtained with increasing the water leaching temperature and time. For bagasse biochar carbonized at 300 °C, the deashing rate reaches 57% at the water leaching temperature of 40 °C for 4 h. Compared with water leaching without carbonization, the proposed method can increase the content of fixed carbon and the char yield by 7% and 3%, respectively. It is because in the process of deashing, CO<sub>2</sub> diffuses and dissolves into water to form carbonic acid which reacts with part of metal salts to form water-soluble salts, resulting in the removal rate of K, Na and Ca up to above 50%, and part removal of calcite and dolomite. Also, the proposed process shows higher deashing efficiency and universality, but the deashing degree is closely related to the ash composition and kinds in biochar. As to peanut shell and poplar, the deashing rate exceeds 30% by carbonization at 300 °C and CO<sub>2</sub>-enhanced water leaching at 40 °C for 4 h.</p></div>","PeriodicalId":15956,"journal":{"name":"燃料化学学报","volume":null,"pages":null},"PeriodicalIF":0.0000,"publicationDate":"2023-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"1","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"燃料化学学报","FirstCategoryId":"1087","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S1872581322600598","RegionNum":0,"RegionCategory":null,"ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q3","JCRName":"Energy","Score":null,"Total":0}
引用次数: 1
Abstract
Ash content is an important factor affecting the quality and combustion performance of biochar. In this paper, a method of ash removal from biomass is proposed by carbonization followed by CO2-enhanced water leaching. The effects of the carbonization temperature of bagasse, the temperature and time of CO2-enhanced water leaching on the deashing were investigated. The results show that the deashing rate firstly increases and then decreases with the carbonization temperature, while the opposite trend is obtained with increasing the water leaching temperature and time. For bagasse biochar carbonized at 300 °C, the deashing rate reaches 57% at the water leaching temperature of 40 °C for 4 h. Compared with water leaching without carbonization, the proposed method can increase the content of fixed carbon and the char yield by 7% and 3%, respectively. It is because in the process of deashing, CO2 diffuses and dissolves into water to form carbonic acid which reacts with part of metal salts to form water-soluble salts, resulting in the removal rate of K, Na and Ca up to above 50%, and part removal of calcite and dolomite. Also, the proposed process shows higher deashing efficiency and universality, but the deashing degree is closely related to the ash composition and kinds in biochar. As to peanut shell and poplar, the deashing rate exceeds 30% by carbonization at 300 °C and CO2-enhanced water leaching at 40 °C for 4 h.
期刊介绍:
Journal of Fuel Chemistry and Technology (Ranliao Huaxue Xuebao) is a Chinese Academy of Sciences(CAS) journal started in 1956, sponsored by the Chinese Chemical Society and the Institute of Coal Chemistry, Chinese Academy of Sciences(CAS). The journal is published bimonthly by Science Press in China and widely distributed in about 20 countries. Journal of Fuel Chemistry and Technology publishes reports of both basic and applied research in the chemistry and chemical engineering of many energy sources, including that involved in the nature, processing and utilization of coal, petroleum, oil shale, natural gas, biomass and synfuels, as well as related subjects of increasing interest such as C1 chemistry, pollutions control and new catalytic materials. Types of publications include original research articles, short communications, research notes and reviews. Both domestic and international contributors are welcome. Manuscripts written in Chinese or English will be accepted. Additional English titles, abstracts and key words should be included in Chinese manuscripts. All manuscripts are subject to critical review by the editorial committee, which is composed of about 10 foreign and 50 Chinese experts in fuel science. Journal of Fuel Chemistry and Technology has been a source of primary research work in fuel chemistry as a Chinese core scientific periodical.