• 关键词：污泥  稻秆  共热解  生物炭  协同作用

• 基金项目：广东省科技计划项目(No.2012B010500036);广东省农业科技成果转化项目(No.2012NL040);广东省中国科学院全面战略合作项目(No.2012B091100271);国家自然科学基金(No.31100353)

• 王定美
• 1. 广东省生态环境与土壤研究所, 广州 510650;2. 中国热带农业科学院环境与植物保护研究所, 海口 571101

• 王跃强
• 广东省生态环境与土壤研究所, 广州 510650

• 余震
• 广东省生态环境与土壤研究所, 广州 510650

• 刘静
• 广东省生态环境与土壤研究所, 广州 510650

• 周顺桂
• 广东省生态环境与土壤研究所, 广州 510650

• 摘要：为了研究共热解对生物炭中碳氮固定的协同效应,利用管式固定炉开展了不同热解温度(300~700 ℃)下的污泥与稻秆单独热解及其共热解(泥秆质量分别为1:3、1:1、3:1)试验研究.结果发现,污泥和稻秆共热解并不是两种物料单独热解贡献的简单叠加.共热解对生物炭产率无协同效应,但对固定碳产率的协同性受共热解条件影响较大.在相同热解温度下,1:3和3:1泥秆比共热解生物炭中的碳和氮含量协同量化值均明显大于1:1泥秆比下的协同量化值,碳和氮元素含量协同量化值分别在热解温度和泥秆比为(400 ℃、1:3)与(400 ℃、3:1)时达到最大值12.43%与40.65%.碳和氮固定率协同量化值随热解温度的升高而增加,最大分别为53.77%~56.13%和38.30%~39.12%,说明共热解可显著提高生物炭中碳和氮元素的固定水平.除3:1泥秆比共热解生物炭中H/C原子比大于理论值,对降低生物炭的芳香度与饱和度具协同作用外,其他共热解条件下的H/C、(O+N)/C、O/C原子比均小于理论值,对提高生物炭的稳定性具明显的协同促进作用.污泥与稻秆在泥秆比1:3、1:1与3:1下共热解,提高协同效应的方式分别为促进脱氧去氢反应、去氢反应与脱氧反应.该研究结果可为生物炭在碳氮封存减排中的应用提供新的工艺途径.

• Abstract：This study compared the sole pyrolysis of sewage sludge (SS) or rice straw (RS) with co-pyrolysis of SS/RS at different mass ratios (1:3, 1:1, and 3:1) regarding with biochar production, C and N transformations and elemental composition. The pyrolysis were carried out with a tube fixed-bed reactor at different temperatures of 300~700 ℃. The results indicated that co-pyrolysis of SS and RS was not a simple addition of the individual contribution of the two. Co-pyrolysis of SS and RS had no synergistic effect on the biochar yield. However, the synergistic effect of co-pyrolysis on fixed-carbon yield was dependent on co-pyrolysis conditions. At the same pyrolysis temperature, the values of synergistic effect (Δs) of carbon and nitrogen contents in biochars from 1:3 and 3:1 SS/RS were significantly higher than those from 1:1 SS/RS. The maximum ΔC of 12.43% and the maximum ΔN of 40.65% were observed using a mass ratio of 1:3 SS/RS and 3:1 SS/RS at a pyrolysis temperature of 400 ℃, respectively. As the pyrolysis temperature increased, the synergistic effects of co-pyrolysis on C and N fixing increased, reaching a maximum value of 53.77%~56.13% and 38.30%~39.12%, respectively. This suggested that co-pyrolysis is benefit for fixing C and N in biochar. Except that the atomic ratio of H/C in the biochar from 3:1 SS/RS was higher that its theoretical value, the atomic ratios of H/C, (O+N)/C and O/C were all lower than their theoretical values under other co-pyrolysis conditions (i.e.,SS/RS ratio, temperature). This indicated that co-pyrolysis had evident positive synergistic effects on biochar stability. The synergistic effects of co-pyrolysis of SS and RS were enhanced by deoxygenation and dehydrogenation, dehydrogenation, and deoxygenation when SS/RS was in ratios of 1:3, 1:1 and 3:1, respectively. The results showed that the effect of carbon and nitrogen fixation in biochar can be significantly enhanced using co-pyrolysis of SS and RS with an optimal mixture ratio, and this provides a new technology for C and N sequestration to mitigate climate change.

• Key words：sewage sludge  rice straw  co-pyrolysis  biochar  synergies

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