污泥基活性炭-甲醇工质对吸附/解吸特性

Adsorption/desorption characteristics of sludge-based activated carbon and methanol

将市政生物污泥资源转化与吸附制冷能效提升相交叉融合,通过炭素前驱体进行复配、KOH催化炭化及磷酸催化活化相结合的压块炭改进工艺对污泥基活性炭的孔结构进行原位调控,制备了4种新型污泥基活性炭(WNC-4/3/2/1);对比研究了以污泥炭和甲醇制冷剂为工质对的吸附制冷床的吸附/脱附循环、制冷量及制冷功率变化特性.结果表明:KOH和磷酸浸渍过程可分别促进微孔及中孔结构的发育,WNC-4的总孔、微孔及中孔容积分别达到0.6960,0.1641和0.5319cm^(3)/g.比表面积与孔结构容积水平的同步提升与甲醇制冷剂吸附/脱附量呈良好的相关性(R^(2)>0.90).基于Langmuir吸附等温模型(R^(2)=0.9939)计算的最大吸附量Q_(L)^(*)达到(552.67±23.83)mg/g;基于Sokoda-Suzuki方程计算的40min内的平衡吸附量和脱附量分别为(372.94±9.504)和(412.55±8.309)mg/g.脱附温度为100℃时,WNC-4吸附制冷系统的稳定脱附量、制冷量和制冷功率分别达到(328.81±10.74)mg/g,(300.34±9.81)kJ/kg和(600.68±19.62)kJ/(kg·h).

Interdisciplinary research was conducted between sewage sludge reclamation and adsorption refrigeration.Pore structure regulation was investigated using sewage sludge as the main carbon precursor,and effects of KOH-catalytic carbonization and phosphoric-acid catalytic activation were clarified.And four new types of sludge-based activated carbons(WNC-4/3/2/1)were prepared by innovative procedure.Performances in terms of adsorption/desorption capacities,refrigerating capacities and refrigerating power were conducted,based on WNC-methanol adsorption refrigeration working pair.Results suggested that the impregnation process of KOH and phosphoric acid resulted in increasing of microporous and mesoporous structures,respectively.Especially,total-,micro-and meso-porous volumes of the new carbon WNC-4 researched to 0.6960,0.1641 and 0.5319 cm^(3)/g,respectively,which was prepared by combined catalysis of KOH and phosphoric acid.The correlation analysis between the specific surface area/pore structure distribution and Q_(L)^(*) showed that degree of mesoporous volumes have the most significant correlation with methanol adsorption capacity(R^(2)>0.90).The maximum adsorption capacity(Q_(L)^(*))calculated by Langmuir adsorption isotherm model(R2=0.9939)reached to 552.67±23.83 mg/g.The equilibrium adsorption and desorption capacities within 40 min obtained by Sokoda-Suzuki equation were(372.94±9.504)and(412.55±8.309)mg/g,respectively.The desorption capacity,refrigerating capacity and power reached to(327.95±10.56)mg/g,(299.55±7.87)kJ/kg and(599.10±8.15)kJ/(kg·h),respectively,under 100℃ of desorption temperature.