不同裂解温度的污泥生物质炭理化特性分析

研究裂解温度对污泥生物质炭基础理化性质的影响,为安全、合理、高效处置污泥提供理论依据。将干燥污泥分别在200、300、500、700℃下进行热裂解处理(SBC200、SBC300、SBC500、SBC700),获得污泥生物质炭,测定其基础理化特性。结果表明：不同温度制备的污泥生物质炭表面颗粒结构完好,孔径范围均集中在10~50 μm,其中低温生物质炭SBC200表面较光滑,最可几孔径和中值孔径最大,分别为20.1 μm和14.8 μm,高温生物质炭SBC700表面较粗糙,比表面积最大,为5.98 m²/g。随裂解温度的提高,污泥生物质炭的产率、含水量、电导率、挥发分、阳离子交换量显著下降,全碳、氧、全氮、氢含量、有效磷和铵态氮均逐渐降低,pH和灰分含量显著增加。将污泥制备成生物质炭,是安全处置污泥的有效途径,低温制得的污泥生物质炭具有更大的提高土壤肥力的潜力,而高温制得的生物质炭在改良土壤酸性的应用上具有更大的潜力。

Analysis of Physical and Chemical Properties of Sludge-based Biochar at Different Pyrolysis Temperatures

To study the effect of pyrolysis temperature on the basic physical and chemical properties of sludge-based biochar, so as to provide a theoretical basis for the safe, reasonable and efficient disposal of sludge, dried sludge was pyrolyzed at 200, 300, 500 and 700 ℃ (SBC200、SBC300、SBC500、SBC700), respectively, and the basic physical and chemical properties of sludge-based biochar were determined. The results showed that the surface particle structure of the biochar prepared at different temperatures was not damaged. The pore size was in the range of 10-50 μm. The surface of SBC200 was smooth, the most probable pore size and the median pore size were the largest, which were 20.1 μm and 14.8 μm, respectively. The surface of the SBC700 was rough, with the largest specific surface area of 5.98 m²/g. With the increase of pyrolysis temperature, the yield, water content, conductivity, volatile matter and cation exchange capacity of sludge-based biochar decreased significantly. The total carbon, oxygen, total nitrogen, hydrogen content, available phosphorus and ammonium nitrogen decreased gradually. The pH and ash content of sludge-based biochar increased significantly with the increase of pyrolysis temperature. The preparation of biochar is an effective way to dispose sludge safely. The sludge-based biochar prepared at low temperature has great potential to improve soil fertility, while the biochar prepared at high temperature has great potential to improve the pH of acid soil.