Utilization of domestic waste biomass char in the context of carbon neutrality—low NOx decoupled combustion
-
摘要: 乡镇生活垃圾的碳、氮含量较高,直接燃烧造成大量CO2和NOx的排放,通过热解后的生物质炭可以将燃烧烟气中的NO还原为N2,利用碳资源的同时,可以降低NOx的排放。以乡镇生活垃圾中四类(纸类、橡塑类、木竹类和纺织类)六种典型组分作为实验原料,在固定床反应器上进行热解与解耦燃烧实验,在低碳排放的基础上,考察解耦燃烧对乡镇生活垃圾燃烧时NOx排放的抑制作用。结果表明,当热解温度为700 ℃,物料粒径为1.6–2.5 mm时,热解气中还原性气体浓度较高,生物质炭对NO的还原率达到60%以上。与传统燃烧和空气分级燃烧时N转化率相比,解耦燃烧的NOx减排率分别为44.1%和18.1%,具有明显控制NOx排放效果。因此,基于热解的乡镇生活垃圾解耦燃烧是一种有效控制NOx排放的方式,有利于乡镇生活垃圾的清洁高效转化与利用。Abstract: The carbon and nitrogen content of township waste is high, and direct combustion causes a large amount of CO2 and NOx emissions. The biomass carbon after pyrolysis can reduce the NO in the combustion flue gas to N2, which can reduce NOx emissions while using carbon resources. Using 6 typical components in 4 kinds of rural solid waste (including paper, plastic, wood and textile) as experimental materials, the pyrolysis and decoupling combustion experiments are carried out in a fixed-bed reactor to investigate the effect of decoupling combustion on NOx emission. The experimental results showed that when the pyrolysis temperature was 700 ℃ and the particle size were 1.6–2.5 mm, the concentration of reducing gas in pyrolysis gas was higher and the reduction rate of NO in the char reached over 60%. By comparing the N conversion of decoupling combustion with that of normal combustion and air staged combustion, the NOx emission reduction rates of the decoupling combustion were 44.1% and 18.1%, respectively. Therefore, the decoupling combustion of rural solid waste based on pyrolysis is an effective way to control NOx emission, which is conducive to the clean and efficient transformation and utilization of rural solid waste.
-
Key words:
- rural solid waste /
- pyrolysis /
- biomass /
- decoupling combustion /
- NOx emission
-
图 2 热解(a)和燃烧(b)实验装置示意图
Figure 2 Schematic diagram of the experimental apparatus of pyrolysis (a) and combustion (b)
(a) 1: Mass flowmeter; 2: Temperature controller; 3: Heating electric furnace; 4: Fixed bed reactor; 5: Condensing tube; 6: Cold hydrazine; 7: Acetone; 8: Wet flowmeter; 9: NaHCO3; 10: Color-changing silica gel; 11: Air bag; 12: Meteorological chromatograph (b) 1: Gas cylinder; 2: Mass flowmeter; 3: Rotor flowmeter; 4: Outer tube; 5: Inner tube; 6: Heating electric furnace; 7: Temperature controller; 8: Flue gas analyzer; Ⅰ, Ⅱ, Ⅲ: gas import or export
表 1 原料的工业分析与元素分析
Table 1 Proximate and ultimate analyses of samples
Material Proximate analysis wad/% Elemental analysis wdaf/% A V FC C H N S O* Plastic 9.76 82.89 7.35 87.02 6.28 1.52 0.06 5.12 Cotton 8.36 88.53 3.12 48.28 7.51 1.77 0.12 42.32 Rice husk 15.17 66.85 17.98 51.42 6.81 0.34 0.14 41.28 Wood 5.21 80.04 14.75 57.34 7.29 0.39 0.41 34.57 Paper 7.01 84.76 8.23 45.51 5.76 0.40 0.35 47.98 Chemical fiber 0.27 87.10 12.63 61.06 4.34 1.56 0.15 32.88 *: by difference, ad: air dry basis; daf: dry and ash free basis -
[1] 郝彦龙, 侯成林, 付丽霞, 李洪瑞, 唐行鹏. 生活垃圾无害化处理工程设计实例[J]. 环境工程,2020,38(2):135−139. doi: 10.13205/j.hjgc.202002019HAO Yan-long, HOU Cheng-lin, FU Li-xia, LI Hong-rui, TANG Xing-peng. Engineering design of a municipal solid waste disposal project[J]. Environ Eng,2020,38(2):135−139. doi: 10.13205/j.hjgc.202002019 [2] 田阳, 项娟, 路垚, 李妍, 梁海恬, 何宗均. 生活垃圾堆肥处理研究[J]. 中国资源综合利用,2020,38(11):56−60. doi: 10.3969/j.issn.1008-9500.2020.11.016TIAN Yang, XIANG Juan, LU Yao, LI Yan, LIANG Hai-tian, HE Zong-jun. Research on domestic waste composting treatment[J]. China Res Compr Util,2020,38(11):56−60. doi: 10.3969/j.issn.1008-9500.2020.11.016 [3] 邓乂寰, 刘抒悦, 吴坤, 赵泉林, 叶正芳. 中国生活垃圾主要处理方式和年运行费用分析及“十四五”政策研究[J]. 环境科学与管理,2021,46(4):9−13. doi: 10.3969/j.issn.1673-1212.2021.04.007DENG Yi-huan, LIU Shu-yue, WU Kun, ZHAO Quan-lin, YE Zheng-fang. Analysis on disposal methods and annual costs of domestic waste in china and policy suggestions for the 14th five-year plan[J]. Environ Sci Manage,2021,46(4):9−13. doi: 10.3969/j.issn.1673-1212.2021.04.007 [4] 李丹, 陈冠益, 马文超, 段宁. 中国村镇生活垃圾特性及处理现状[J]. 中国环境科学,2018,38(11):4187−4197. doi: 10.3969/j.issn.1000-6923.2018.11.026LI Dan, CHEN Guan-yi, MA Wen-chao, DUAN Ning. Characteristics and treatment status of rural solid waste in China[J]. China Environ Sci,2018,38(11):4187−4197. doi: 10.3969/j.issn.1000-6923.2018.11.026 [5] 2021年中国统计年鉴[M]. 国家统计局, 2022.China Statistical Yearbook 2021 [M]. National Bureau of Statistics, 2022. [6] 罗永浩, 陈祎, 杨明辉, 陆杰, 武桐. 生活垃圾典型组分热解及NOx前驱物析出特性研究[J]. 农业工程学报,2018,34(S1):143−148.LUO Yong-hao, CHEN Yi, YANG Ming-hui, LU Jie, WU Tong. Research on pyrolysis of typical component of municipal solid waste and release characteristics of NOx precursor[J]. Trans Chin Soc Agr Eng,2018,34(S1):143−148. [7] ATES F, MISKOLCZI N, BORSODI N. Comparision of real waste (MSW and MPW) pyrolysis in batch reactor over different catalysts. Part I: product yields, gas and pyrolysis oil properties[J]. Bioresour Technol,2013,133:443−454. doi: 10.1016/j.biortech.2013.01.112 [8] GLARBORG P, JENSEN A D, JOHNSSON J E. Fuel nitrogen conversion in solid fuel fired systems[J]. Prog Energy Combust Sci,2003,29(2):89−113. doi: 10.1016/S0360-1285(02)00031-X [9] TOMITA A. Reprint of: pyrolysis technologies for municipal solid waste: A review[J]. Fuel Process Technol,2001,71:18. [10] HE J, SONG W, GAO S, DONG L, BARZ M, LI J, LIN W. Experimental study of the reduction mechanisms of NO emission in decoupling combustion of coal[J]. Fuel Process Technol,2006,87(9):803−810. doi: 10.1016/j.fuproc.2006.04.003 [11] 尚校, 高士秋, 汪印, 董利, 许光文, 郭景海. 不同煤燃烧方式降低NOx排放比较及解耦燃烧应用[J]. 燃料化学学报,2012,40(6):673−670.SHANG Xiao, GAO Shi-qiu, WANG Yin, DONG Li, XU Guang-wen, GUO Jing-hai. Comparison of NOx reduction among different coal combustion methods and the application of decoupling combustion[J]. J Fuel Chem Technol,2012,40(6):673−670. [12] DONG L, GAO S, XU G. NO reduction over biomass char in the combustion process[J]. Energy Fuels,2010,24(1):446−450. doi: 10.1021/ef900913p [13] CHEN D, YIN L, WANG H, HE P. Reprint of: Pyrolysis technologies for municipal solid waste: A review[J]. Waste Manag,2015,37:116−136. doi: 10.1016/j.wasman.2015.01.022 [14] BAI J S, YU C J, LI L M, WU P, LUO Z Y, NI M J. Experimental study on the NO and N2O formation characteristics during biomass combustion[J]. Energy Fuels,2013,27:515−522. [15] 李旺. 基于褐煤半焦中温高效脱除烟气中NOx的研究[D]. 武汉: 武汉科技大学, 2017.LI Wang. Study on Efficient removal of NOx in flue gases by semi-coke in the medium temperature[D]. Wuhan: Wuhan University of Science and Technology, 2017. [16] KLOSS S, ZEHETNER F, DELLANTONIO A, ET AL. HAMID R, OTTNER F, LIEDTKE V, SCHWANNINGER M, GERZABEK M H, SOJA G. Characterization of slow pyrolysis biochars: effects of feedstocks and pyrolysis temperature on biochar properties[J]. J Environ Qual,2012,41(4):990−1000. doi: 10.2134/jeq2011.0070 [17] ZHAO J, WANG S, WU Z, MENG H, CHEN L. Hydrogen-rich syngas produced from the co-pyrolysis of municipal solid waste and wheat straw[J]. Int J Hydrogen Energy,2017,42(31):19701−19708. doi: 10.1016/j.ijhydene.2017.06.166 [18] MORRIS R M. Effects of particle size and temperature on volatiles produced from coal by slow pyrolysis[J]. Fuel,1990,69(6):776−779. doi: 10.1016/0016-2361(90)90045-R [19] 王瑜堂, 张军, 岳波, 王敦球, 於俊颖, 黄启飞, 吴小卉, 靳琪. 村镇生活垃圾重金属含量及其土地利用中的环境风险分析[J]. 农业环境科学学报,2017,36(8):1634−1639. doi: 10.11654/jaes.2016-1593WANG Yu-tang, ZHANG Jun, YUE Bo, WANG Dun-qiu, YU Jun-ying, HUANG Qi-fei, WU Xiao-hui, JIN Qi. Heavy metal content of the rural solid waste and its land utilization environmental risk analysis[J]. J Agro-Environ Sci,2017,36(8):1634−1639. doi: 10.11654/jaes.2016-1593 [20] SIDDIQI H, KUMARI U, BISWAS S, MISHRA A, MEIKAP B C. A synergistic study of reaction kinetics and heat transfer with multi-component modelling approach for the pyrolysis of biomass waste[J]. Energy,2020,204:117933. doi: 10.1016/j.energy.2020.117933 [21] PAN L, DAI F, PEI S, HUANG J, LIU S. Influence of particle size and temperature on the yield and composition of products from the pyrolysis of Jimsar (China) oil shale[J]. J Anal Appl Pyrolysis,2021,157:105211. doi: 10.1016/j.jaap.2021.105211 [22] WANG D, CHEN Z, LI C, WANG D, LI Y, YANG H, LIU Z, YU J, GAO S. High-quality tar production from coal in an integrated reactor: Rapid pyrolysis in a drop tube and downstream volatiles upgrading over char in a moving bed[J]. Fuel,2021,285:119156. doi: 10.1016/j.fuel.2020.119156 [23] 邓飞虎, 王黎. 轮胎粒径对热解产物的影响[J]. 应用化工,2019,48(6):1382−1384. doi: 10.3969/j.issn.1671-3206.2019.06.031DENG Fei-hu, WANG Li. Influences of tire size on pyrolysis products[J]. Appl Chem Ind,2019,48(6):1382−1384. doi: 10.3969/j.issn.1671-3206.2019.06.031 [24] CHEN Y, FANG Y, YANG H, XIN S, ZHANG X, WANG X, CHEN H. Effect of volatiles interaction during pyrolysis of cellulose, hemicellulose, and lignin at different temperatures[J]. Fuel,2019,248:1−7. doi: 10.1016/j.fuel.2019.03.070 [25] WANG C, BI H, LIN Q, JIANG X, JIANG C. Co-pyrolysis of sewage sludge and rice husk by TG-FTIR-MS: Pyrolysis behavior, kinetics, and condensable/non-condensable gases characteristics[J]. Renewable Energy,2020,160:1048−1066. doi: 10.1016/j.renene.2020.07.046 [26] XIAO R, YANG W. Influence of temperature on organic structure of biomass pyrolysis products[J]. Renewable Energy,2013,(50):136−140. [27] TOMITA A. Suppression of nitrogen oxides emission by carbonaceous reductants[J]. Fuel Process Technol,2001,71(1):53−70. [28] ZAWADZKI J, WISNIEWSKI M. Adsorption and decomposition of NO on carbon and carbon-supported catalysts[J]. Carbon,2002,40(1):119−124. doi: 10.1016/S0008-6223(01)00081-1 [29] ZHANG H, JIANG X, LIU J, SHEN J. New insights into the heterogeneous reduction reaction between NO and char-bound nitrogen[J]. Ind Eng Chem Res,2014,53(15):6307−6315. doi: 10.1021/ie403920j [30] 牛欣, 肖军. 污泥化学链燃烧过程中氮迁移转化特性研究[J]. 燃料化学学报,2017,45(4):506−513. doi: 10.3969/j.issn.0253-2409.2017.04.016NIU Xin, XIAO Jun. Nitrogen transformation in chemical looping combustion of sewage sludge[J]. J Fuel Chem Technol,2017,45(4):506−513. doi: 10.3969/j.issn.0253-2409.2017.04.016 [31] LIAO X, SHAO J, ZHANG S, LI X, YANG H, WANG X, CHEN H. Effects of CO2 and CO on the reduction of NO over calcined limestone or char in oxy-fuel fluidised bed combustion[J]. IET Renew Power Gener,2019,13(10):1633−1640. doi: 10.1049/iet-rpg.2018.6277