{"title":"Effect of acid washing and torrefaction combined pretreatment on the properties of waste tobacco stem biomass and the quality of pyrolysis bio-oil.","authors":"Anni Wang, Jianhang Hu, Long Zhang, Hua Wang","doi":"10.3389/fchem.2025.1603584","DOIUrl":null,"url":null,"abstract":"<p><p>Aiming at the issues of low yield and poor quality of bio-oil obtained from direct pyrolysis of biomass, in this study, waste tobacco stems (TS) were used as raw materials, and the pretreatment methods of torrefaction and acid washing were adopted to study the effects of different torrefaction temperatures and pretreatment sequences on the quality of TS biomass and bio-oil. Results showed that combined pretreatment synergistically integrated deoxygenation from torrefaction and deashing from acid washing. High-temperature torrefaction-based combined pretreatment reduced TS oxygen content from 54.83% to 20.14%. Acid washing pretreatment achieved more than 90% removal of inorganic elements (K, Cl and Mg). The order of combined pretreatment also had an important influence on biomass pyrolysis. Torrefaction-acid washing pretreatment decreased ash content of TS, increased the relative content of sugars and aromatic compounds in bio-oil, reduced alcohols and ketones relative contents, and improved bio-oil higher heating value (HHV) and pH. Acid washing-torrefaction pretreatment enhanced bio-oil productivity, increased nitrogen-containing compounds and phenols relative content, reduced acids and aldehydes contents, and lowered bio-oil water and ash contents. Additionally, with the increase in torrefaction temperature, the O/C molar ratio of TS decreased, the HHV of TS increased, and the thermal cracking of nicotine in bio-oil to generate pyridine compounds was promoted. This study demonstrates a viable pathway to convert TS into high-quality fuels and bio-oil via combined pretreatment, offering new insights for optimizing biomass pyrolysis technology and enhancing resource utilization efficiency.</p>","PeriodicalId":12421,"journal":{"name":"Frontiers in Chemistry","volume":"13 ","pages":"1603584"},"PeriodicalIF":3.8000,"publicationDate":"2025-06-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12187669/pdf/","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Frontiers in Chemistry","FirstCategoryId":"92","ListUrlMain":"https://doi.org/10.3389/fchem.2025.1603584","RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"2025/1/1 0:00:00","PubModel":"eCollection","JCR":"Q2","JCRName":"CHEMISTRY, MULTIDISCIPLINARY","Score":null,"Total":0}
引用次数: 0
Abstract
Aiming at the issues of low yield and poor quality of bio-oil obtained from direct pyrolysis of biomass, in this study, waste tobacco stems (TS) were used as raw materials, and the pretreatment methods of torrefaction and acid washing were adopted to study the effects of different torrefaction temperatures and pretreatment sequences on the quality of TS biomass and bio-oil. Results showed that combined pretreatment synergistically integrated deoxygenation from torrefaction and deashing from acid washing. High-temperature torrefaction-based combined pretreatment reduced TS oxygen content from 54.83% to 20.14%. Acid washing pretreatment achieved more than 90% removal of inorganic elements (K, Cl and Mg). The order of combined pretreatment also had an important influence on biomass pyrolysis. Torrefaction-acid washing pretreatment decreased ash content of TS, increased the relative content of sugars and aromatic compounds in bio-oil, reduced alcohols and ketones relative contents, and improved bio-oil higher heating value (HHV) and pH. Acid washing-torrefaction pretreatment enhanced bio-oil productivity, increased nitrogen-containing compounds and phenols relative content, reduced acids and aldehydes contents, and lowered bio-oil water and ash contents. Additionally, with the increase in torrefaction temperature, the O/C molar ratio of TS decreased, the HHV of TS increased, and the thermal cracking of nicotine in bio-oil to generate pyridine compounds was promoted. This study demonstrates a viable pathway to convert TS into high-quality fuels and bio-oil via combined pretreatment, offering new insights for optimizing biomass pyrolysis technology and enhancing resource utilization efficiency.
期刊介绍:
Frontiers in Chemistry is a high visiblity and quality journal, publishing rigorously peer-reviewed research across the chemical sciences. Field Chief Editor Steve Suib at the University of Connecticut is supported by an outstanding Editorial Board of international researchers. This multidisciplinary open-access journal is at the forefront of disseminating and communicating scientific knowledge and impactful discoveries to academics, industry leaders and the public worldwide.
Chemistry is a branch of science that is linked to all other main fields of research. The omnipresence of Chemistry is apparent in our everyday lives from the electronic devices that we all use to communicate, to foods we eat, to our health and well-being, to the different forms of energy that we use. While there are many subtopics and specialties of Chemistry, the fundamental link in all these areas is how atoms, ions, and molecules come together and come apart in what some have come to call the “dance of life”.
All specialty sections of Frontiers in Chemistry are open-access with the goal of publishing outstanding research publications, review articles, commentaries, and ideas about various aspects of Chemistry. The past forms of publication often have specific subdisciplines, most commonly of analytical, inorganic, organic and physical chemistries, but these days those lines and boxes are quite blurry and the silos of those disciplines appear to be eroding. Chemistry is important to both fundamental and applied areas of research and manufacturing, and indeed the outlines of academic versus industrial research are also often artificial. Collaborative research across all specialty areas of Chemistry is highly encouraged and supported as we move forward. These are exciting times and the field of Chemistry is an important and significant contributor to our collective knowledge.