裂解温度对海南不同材料生物炭理化特性的影响

为探求热带地区生物质在制备生物炭时对温度的响应,以热带地区植物桉树、橡胶树和椰糠为原料,在300、500和700℃下制备成桉树炭(E)、橡胶树炭(RT)和椰糠炭(SC),利用元素分析仪、扫描电镜(SEM)、X射线能谱分析仪(EDS)和傅立叶红外光谱分析仪(FTIR)等研究不同裂解温度对生物炭的酸碱度、结构及元素组成和含...

Effect of Pyrolysis Temperature on the Physicochemical Properties of Biochar from Different Materials in Hainan

In order to explore the temperature response of biomass in the preparation of biochar in tropical areas, eucalyptus, rubber tree and coco bran were used as the raw materials to prepare eucalyptus charcoal (E) and rubber tree charcoal (RT) and coconut bran charcoal (SC) at 300, 500 and 700℃. Elemental analyzer, scanning electron microscope (SEM), X-ray energy spectrum analyzer (EDS) and Fourier infrared spectroscopy (FTIR) were used to study the pH, structure and element composition of biochar at different pyrolysis temperatures. With the increase of pyrolysis temperature, the ash content and pH of the three biochar increased, and the increase of 300?500℃ (17.60%?27.59%) was significantly higher than that of 500?700℃ (4.97%?10.47%). When the pyrolysis temperature was 300 and 500℃, the pH value was E > SC > RT, and when the temperature was 700℃, and that was SC > E > RT. With the increase of temperature, the yield of the three biochars decreased. At each temperature, the yield of SC was significantly higher than that of E and RT. C/N comparison showed that RT>E>SC under all temperature conditions. SC contained more elements, while E and RT had higher C content. When the pyrolysis temperature was 300?500℃, the -OH vibration peak (3432 cm^?1) of E and RT increased with the increase of temperature, and the peak value decreased when the temperature increased to 700℃. SC was within 300?700℃, -OH vibration peak increased with increasing temperature. When the wavelength was 1659?1744 cm^?1, when the C=C vibration peak of E and RT was 300?500℃, it increased with the temperature rise. At this time, the temperature rose again, the peak difference was not big, SC was 300?700℃, the peak value increased with increasing temperature. At 2800?3000 cm^?1, aliphatic CH₃ and CH₂ groups appeared. When the cracking temperature was higher than 500℃, the vibration peak of E was basically the same as 700℃, while the vibration peak of RT decreased at 700℃. The absorption peak in the 785?880 cm^?1 band was the aromatic ring C-H bending vibration. When the cracking temperature was higher than 500℃, the vibration peaks formed by the three raw materials all decreased with the increase of temperature. The results of this study show that the elemental composition, surface characteristics and functional groups of biochar prepared from coconut bran are quite different from those of biochar prepared from eucalyptus and rubber trees, and it is more sensitive to the pyrolysis temperature.