Effect of biomass type and pyrolysis temperature on nitrogen in biochar, and the comparison with hydrochar. (1st May 2021)

• Record Type: Journal Article
• Authors: Xu, Siyu; Chen, Jiefeng; Peng, Haoyi; Leng, Songqi; Li, Hui; Qu, Wenqi; Hu, Yingchao; Li, Hailong; Jiang, Shaojian; Zhou, Wenguang; Leng, Lijian
• Is Part Of: Fuel. Volume 291(2021)
• Publication Date: 2021-05-01
• Subjects: HTC Hydrothermal Carbonization -- HTL Hydrothermal Liquefaction -- N Nitrogen -- SS Soybean Straw -- CL Chlorella -- AP Aqueous phase -- SS-T/CL-T (T = 300 400 500 600 700 800 °C) Biochar of SS/CL at various pyrolysis temperature -- SS-n/CL-n (n = 0 1 2 3 4) Hydrochar of SS/CL with aqueous phase recirculation, and n means the recirculation times -- C Carbon -- H Hydrogen -- O Oxygen -- VM Volatile Matter -- FC Fixed Carbon -- TG Thermogravimetric Analysis -- DTG Derivative Thermogravimetry; Biochar -- Hydrochar -- Pyrolysis temperature -- Nitrogen containing functional groups -- Soybean straw -- Microalgae; Fuel -- Periodicals; Coal -- Periodicals; Coal; Fuel; Periodicals; 662.6
• DOI: 10.1016/j.fuel.2021.120128
• Languages: English
• ISSNs: 0016-2361

Abstract

Graphical abstract: Highlights: Biomass type and pyrolysis temperature influence Nitrogen content and formation. N existed as pyridinic-N, pyrrolic-N, quaternary-N and pyridinicN-O in biochar. N existed as protein-N, pyridinic-N, pyrrolic-N in hydrochar. N transformation: cyclization, dimerization, ring condensation and oxidation. N stability: protein-N < pyrrolic-N < pyridinic-N < quaternary-N < pyridinicN-O. Abstract: In this paper, two different biomasses (soybean straw and Chlorella ) were pyrolyzed at temperatures 300–800 °C to obtain biochars. The impacts of biomass type and pyrolysis temperature on the physical and chemical properties of biochar, especially the effects on nitrogen (N) content and composition, were investigated. Furthermore, the hydrochar obtained from hydrothermal carbonization (HTC) of the same biomass was compared with the pyrolysis biochar. Biochar N content was positively correlated with biomass N content and negatively correlated with pyrolysis temperature. For raw biomass, N mainly existed as protein-N and inorganic-N, which converted to more stable structures through the pyrolysis process, including pyridinic-N, pyrrolic-N, graphitic-N (or quaternary-N) and pyridinicN-O. While in hydrochar, N-containing species mainly include protein-N, pyrrolic-N and pyridinic-N. Biochar had more kinds of N-containing species, more aromatic structures, and higher stability compared with hydrochar.