松木木屑加压烘焙制备高品质生物焦燃料及其特性研究

doi:10.13304/j.nykjdb.2024.0050

摘要/Abstract

摘要：

为利用农林废弃物以低成本制备高品质生物焦燃料，以雪松木屑（cedar sawdust， CS）为原料，采用微型高压反应釜进行加压烘焙试验，研究烘焙半焦燃料品质的提高和物化结构、热解动力学特性变化以及气体产物组分分布。结果表明，与同温度下（230 ℃）常压烘焙相比，加压烘焙半焦的固定碳含量均有所提高，压力促进了生物质中挥发性物质向固定碳的转化。CS-290-1.5半焦的挥发分从CS原样的84.09%降至45.74%，热值增加到28.15 MJ·kg^-1，燃料品质显著增加，且氧碳比、氢碳比降低至0.24和0.85，基本达到烟煤的燃料性能范围。温度对挥发分的脱除以及脱氧增碳效果起着重要的作用。傅里叶变换红外光谱结果显示，烘焙半焦中含氧基团减少，C=C增加，生物质组分间的脱氧及芳构化反应加强。拉曼试验结果表明，加压下温度的提高使烘焙半焦中小芳香环向大芳香环的缩聚程度提高，石墨化程度增加。随温度升高，固体半焦比表面积与总孔体积呈逐渐增加趋势，CS-290-1.5比表面积高达40.02 m²·g^-1，温度的提高促进了挥发分脱除与小分子气体的生成，导致孔隙数量增加，燃烧反应性增强。热解动力学计算表明，加压烘焙半焦在热解反应后期的活化能显著增加，烘焙半焦中交联反应增强，生成更多热稳定性高的物质。气体组分测定结果表明，相比常压加压烘焙更有利于生物质中纤维素和半纤维素组分的深度分解，促进了含氧基团的大量脱除，更多的以H₂O、CO、CO₂等形式释放。综上表明，借助气体压力增强松木木屑脱氧提质，为芳香类植物废弃物高值能源化利用提供了理论依据。

关键词: 芳香植物, 生物质, 加压烘焙, 脱氧, 活化能

Abstract:

To utilize agricultural and forestry waste to prepare high-quality biochar fuel at low cost， using cedar sawdust （CS） as raw material， pressurized torrefaction experiments were conducted using a micro high-pressure reactor to study fuel quality and the changes in physicochemical structure as well as pyrolysis kinetics. The results showed that，compared with atmospheric torrefaction at the same temperature （230 ℃）， the fixed carbon content of pressurized torrefied semi-char increased. Pressure promoted the conversion of volatile substances to fixed carbon in biomass. The volatile content in CS-290-1.5 decreased from 84.09% of CS to 45.74%， and calorific value increased to 28.15 MJ·kg^-1， the fuel quality significantly increased. The oxygen-carbon and Hydrogen-carbon ratios decreased to 0.24 and 0.85， which had basically reached the fuel quality range of bituminous coal. Temperature played an important role in the volatile matter removal and carbonization. Fourier-transform infrared spectroscopy results showed that oxygen-containing groups in solid products decreased， while C=C increased. The deoxygenation and aromatization reactions between biomass components were strengthened. Raman experimental results showed that the higher temperature under pressure led to an increase in condensation reaction from small to large aromatic rings in torrefied semi-char， resulted in an increase in graphitization degree. As temperature increased， the specific surface area and total pore volume of solid semi-char showed a gradual increase trend. CS-290-1.5 had a specific surface area of 40.02 m²·g^-1， suggesting that the raise in temperature promoted volatile matter removal and the generation of small molecule gases， thereby increasing pores and combustion reactivity. According to pyrolysis kinetics calculation， the activation energy of pressurized torrefied semi-char significantly increased at a later stage of pyrolysis reaction. The cross-linking reaction in torrefied semi-char was enhanced， resulting in the generation of more substances with high thermal stability. The determination results of gas composition indicated that compared to atmospheric pressure， pressurized torrefaction was more conducive to the deep decomposition of cellulose and hemicellulose of biomass， promoting the removal of a large number of oxygen-containing groups， and releasing in the form of H₂O， CO and CO₂. To sum up， using gas pressure could enhance the deoxygenation and quality improvement of pine sawdust， which provided a theoretical basis for the energy efficient utilization of aromatic plant waste.

Key words: aromatic plants, biomass, pressurized torrefaction, deoxygenation, activation energy

中图分类号:

TS69

丁献华, 闫双堆, 闫明. 松木木屑加压烘焙制备高品质生物焦燃料及其特性研究[J]. 中国农业科技导报, 2025, 27(7): 204-216.

Xianhua DING, Shuangdui YAN, Ming YAN. Preparation and Characteristics of High-quality Biochar Fuel by Pressurized Torrefaction of Pine Sawdust[J]. Journal of Agricultural Science and Technology, 2025, 27(7): 204-216.

图/表 13

图1 加压烘焙试验装置

Fig. 1 Pressurized torrefaction experimental device diagram

表1 CS原样及不同压力下加压烘焙半焦工业成分和元素分析

Table 1 Proximate composition and ultimate analysis of CS samples and pressurized torrefied semi-char

样品 Sample	工业成分Proximate composition/%		元素分析 Ultimate analysis/%					高位发热量HHV/（MJ·kg^-1）
样品 Sample	挥发分 V_daf	固定碳 FC_daf	碳C	氢H	氮N	氧O^△	硫S	高位发热量HHV/（MJ·kg^-1）
CS	84.09±2.06 a	15.91±0.81 c	46.71±0.96 c	5.38±0.53 b	0.25±0.01 c	47.51±1.85 a	0.15±0.01 b	14.99±0.75 c
CS-230-AP	76.35±2.00 b	22.65±1.57 b	54.84±1.42 b	5.47±0.14 b	0.76±0.03 a	38.80±0.96 b	0.13±0.00 b	19.44±0.26 b
CS-230-0.5	70.70±1.70 b	27.30±2.30 b	57.94±2.55 b	4.98±1.11 c	0.50±0.04 b	36.48±0.64 b	0.10±0.00 b	20.20±1.20 b
CS-230-1.0	66.02±2.11 b	33.98±2.11 a	63.32±0.95 a	5.05±0.31 c	0.59±0.02 b	30.92±2.02 b	0.12±0.01 b	23.12±1.62 a
CS-230-1.5	63.85±3.14 c	36.15±1.72 a	65.97±3.09 a	5.70±0.28 a	0.48±0.07 b	27.65±1.72 c	0.20±0.01 a	25.54±1.14 a
CS-230-2.0	63.01±2.36 c	36.99±2.85 a	67.00±0.52 a	5.35±0.32 b	0.45±0.07 b	27.06±1.39 c	0.14±0.01 b	25.49±0.81 a

图2 CS原样及230 ℃、不同压力下的烘焙半焦质量产率、氧碳比和氢碳比注：不同小写字母表示不同处理间在P<0.05水平差异显著。Note：Different lowercase letters indicate significant differences between different treatments at P<0.05 level.

Fig. 2 Mass yield， O/C and H/C of torrefied semi-char under different pressures at 230 ℃ and CS samples

表2 CS原样及不同温度下加压烘焙半焦工业成分和元素分析

Table 2 Proximate composition and ultimate analysis of CS samples and pressurized torrefied semi-char

样品 Sample	工业成分Proximate composition/%		元素分析Ultimate analysis/%					高位发热量HHV/（MJ·kg^-1）
样品 Sample	挥发分 V_daf	固定碳 FC_daf	碳C	氢H	氮N	氧O^△	硫S	高位发热量HHV/（MJ·kg^-1）
CS	84.09±2.06 a	15.91±0.81 e	46.71±0.96 c	5.38±0.53 a	0.25±0.01 c	47.51±1.85 a	0.15±0.01 a	14.99±0.75 c
CS-200-1.5	75.83±2.92 b	24.17±0.97 d	54.20±0.96 b	4.85±0.32 b	0.38±0.02 b	40.49±1.24 a	0.08±0.01 b	18.02±0.52 b
CS-230-1.5	63.85±2.46 c	36.15±2.07 c	65.97±2.42 a	5.70±0.24 a	0.48±0.02 b	27.65±0.66 b	0.20±0.00 a	25.54±1.26 a
CS-260-1.5	53.40±1.90 d	46.60±1.30 b	68.78±1.55 a	5.39±0.75 a	0.49±0.02 b	25.25±0.40 b	0.09±0.00 b	26.48±1.03 a
CS-290-1.5	45.74±1.83 e	54.26±2.55 a	71.71±3.01 a	5.63±1.04 a	0.66±0.01 a	22.39±1.63 b	0.15±0.01 a	28.15±1.33 a

图3 CS原样和各温度下固体半焦的H/C-O/C图

Fig. 3 H/C-O/C diagram of solid semi-char at various temperatures and CS samples

图4 CS原样和各温度下固体半焦的FTIR分析

Fig. 4 FTIR analysis of solid semi-char at different temperatures and CS samples

图5 不同温度下CS加压烘焙半焦的拉曼分峰结果A：CS-230-1.5的拉曼分峰；B：各样品分峰面积计算结果

Fig. 5 Raman peak splitting results of CS pressurized torrefied semi-char at different temperaturesA：Raman splitting of CS-230-1.5；B：Peak area results of each sample

表3 CS原样及各温度下固体半焦的BET测试结果

Table 3 BET test results of solid semi-char at different temperatures and CS sample

样品 Sample	比表面积 Specific surface area/（m²·g^-1）	总孔体积 Total pore volume/（cm³·g^-1）	平均孔径 Average pore size/nm
CS	27.47	0.042 9	3.23
CS-230-AP	25.03	0.047 3	5.12
CS-200-1.5	24.25	0.043 9	4.78
CS-230-1.5	37.69	0.056 8	4.38
CS-260-1.5	38.92	0.068 3	3.99
CS-290-1.5	40.02	0.070 4	3.52

图6 CS原样及各温度下固体半焦热解的TG曲线

Fig. 6 TG curves of solid semi-char at various temperatures and CS samples

图7 CS原样及各温度下固体半焦热解的DTG曲线

Fig. 7 DTG curves of solid semi-char at various temperatures and CS samples

图8 CS原样及各温度下固体半焦热解的In（a/T2）-1/T阿伦尼乌斯图

Fig. 8 In（a/T2）-1/T arrhenius plot of solid semi-char at different temperatures and CS samples

图9 CS原样及各温度下烘焙半焦热解的活化能分布曲线

Fig. 9 Activation energy distribution curve of solid semi-char at different temperatures and CS samples

图10 不同压力及温度下烘焙气体产物组成A：230 ℃、不同压力下气体分布；B：1.5 MPa、不同温度下气体分布

Fig. 10 Compositions of torrefied gas products under different pressures and temperaturesA：Gas distribution at 230 ℃ and different pressures；B：Gas distribution at 1.5 MPa and different temperatures

参考文献 30

[1]	FIELD C B, CAMPBELL J E, LOBELL D B.Biomass energy:the scale of the potential resource [J]. Trends Ecol. Evol., 2008,23(2):65-72.
[2]	LONG H L, LI X B, WANG H, et al.. Biomass resources and their bioenergy potential estimation:a review [J]. Renew.Sustain. Energy Rev., 2013, 26: 344-352.
[3]	QUADER M A, AHMED S, GHAZILLA R A R, et al.. A comprehensive review on energy efficient CO₂ breakthrough technologies for sustainable green iron and steel manufacturing [J]. Renew. Sustain. Energy Rev., 2015,50:594-614.
[4]	严云,何强,沙建雄,等.污泥-杏壳基生物质炭的制备工艺优化及对亚甲基蓝吸附研究[J].化工新型材料,2022,50(11):278-282.
	YAN Y, HE Q, SHA J X, et al.. Optimization of the preparation process of sludge-apricot shell-based biomass carbon and its adsorption towards methylene blue [J]. New Chem. Mater.,2022,50(11):278-282.
[5]	BACH Q V, SKREIBERG Ø. Upgrading biomass fuels via wet torrefaction:a review and comparison with dry torrefaction [J].Renew. Sustain. Energy Rev., 2016,54: 665-677.
[6]	孙启祥,彭镇华,张齐生.自然状态下杉木木材挥发物成分及其对人体身心健康的影响[J].安徽农业大学学报,2004,31(2):158-163.
	SUN Q X, PENG Z H, ZHANG Q S. Volatiles of wood of Chinese fir in nature and its effect on human health [J]. J.Anhui Agric. Univ., 2004,31(2):158-163.
[7]	金紫霖,张启翔,潘会堂,等.芳香植物的特性及对人体健康的作用[J].湖北农业科学,2009,48(5):1245-1247.
	JIN Z L, ZHANG Q X, PAN H T, et al.. The aromatic characteristics and healthy effects of the aromatic plants [J].Hubei Agric. Sci., 2009, 48(5):1245-1247.
[8]	DING Y M, HUANG B Q, LI K Y, et al.. Thermal interaction analysis of isolated hemicellulose and cellulose by kinetic parameters during biomass pyrolysis [J/OL]. Energy, 2020, 195:117010 [2023-12-18]. .
[9]	STRANDBERG M, OLOFSSON I, POMMER L, et al.. Effects of temperature and residence time on continuous torrefaction of spruce wood [J]. Fuel Process. Technol., 2015,134:387-398.
[10]	TOOR S S, ROSENDAHL L, RUDOLF A. Hydrothermal liquefaction of biomass:a review of subcritical water technologies [J]. Energy, 2011, 36(5):2328-2342.
[11]	TONG S, SUN Y M, LI X, et al.. Gas-pressurized torrefaction of biomass wastes:Roles of pressure and secondary reactions [J/OL].Bioresour. Technol., 2020, 313:123640 [2023-12-18]. .
[12]	MATALI S, RAHMAN N A, IDRIS S S, et al.. Lignocellulosic biomass solid fuel properties enhancement via torrefaction [J].Procedia Eng., 2016,148:671-678.
[13]	NHUCHHEN D R, BASU P. Experimental investigation of mildly pressurized torrefaction in air and nitrogen [J]. Energy Fuels, 2014, 28(5):3110-3121.
[14]	丁亮,张永奇,黄戒介,等.热解压力对生物质焦结构及气化反应性能的影响[J].燃料化学学报,2014,42(11):1309-1315.
	DING L, ZHANG Y Q, HUANG J J, et al.. Effects of pyrolysis pressure on the properties and gasification reactivities of biomass chars [J]. J. Fuel Chem. Technol., 2014, 42(11):1309-1315.
[15]	WANNAPEERA J, WORASUWANNARAK N. Upgrading of woody biomass by torrefaction under pressure [J]. J. Anal. Appl. Pyrolysis, 2012, 96:173-180.
[16]	AGAR D, DEMARTINI N, HUPA M. Influence of elevated pressure on the torrefaction of wood [J]. Energy Fuels, 2016, 30(3):2127-2136.
[17]	张传佳,李安心,涂德浴.水稻秸秆成型燃料热解特性试验研究[J].中国农业科技导报,2017,19(7):95-100.
	ZHANG C J, LI A X, TU D Y. The experimental study on pyrolysis characteristics of rice straw briquette fuel [J]. J. Agric.Sci. Technol., 2017, 19(7):95-100.
[18]	肖军,沈来宏,王泽明,等.生物质加压热重分析研究[J].燃烧科学与技术,2005,11(5):415-420.
	XIAO J, SHEN L H, WANG Z M, et al.. Pressurized thermogravimetric analysis of pyrolysis of biomass [J].J.Combust. Sci. Technol., 2005, 11(5): 415-420.
[19]	SONOBE T, WORASUWANNARAK N.Kinetic analyses of biomass pyrolysis using the distributed activation energy model [J]. Fuel, 2008, 87(3):414-421.
[20]	DE CAPRARIIS B, SANTARELLI M L, SCARSELLA M, et al..Kinetic analysis of biomass pyrolysis using a double distributed activation energy model [J]. J. Therm. Anal.Calorim., 2015, 121(3): 1403-1410.
[21]	严云,刘洪,曹芮,等.农林废弃生物质的热解特性及动力学研究[J].化工新型材料,2020,48(1):148-151, 156.
	YAN Y, LIU H, CAO R, et al.. Study on pyrolysis characteristics and kinetics of waste biomass in agriculture and forestry [J]. New Chem. Mater., 2020, 48(1):148-151, 156.
[22]	LIU X G, LI B Q, MIURA K. Analysis of pyrolysis and gasification reactions of hydrothermally and supercritically upgraded low-rank coal by using a new distributed activation energy model [J]. Fuel Process. Technol., 2001, 69(1):1-12.
[23]	SATTASATHUCHANA S, PARNTHONG J, YOUNGIAN S,et al..Energy efficiency of bio-coal derived from hydrothermal carbonized biomass:Assessment as sustainable solid fuel for municipal biopower plant [J/OL]. Appl. Therm. Eng., 2023, 221:119789 [2024-12-30]. .
[24]	陈勇,陈登宇,孙琰,等.烘焙脱氧预处理对生物质秸秆燃料品质的影响[J].科学技术与工程,2015,15(11):205-209.
	CHEN Y, CHEN D Y, SUN Y, et al.. Effect of torrefaction on the fuel properties of biomass straw [J]. Sci. Technol. Eng., 2015, 15(11):205-209.
[25]	XIN S Z, YANG H P, CHEN Y Q, et al.. Chemical structure evolution of char during the pyrolysis of cellulose [J]. J. Anal.Appl. Pyrolysis, 2015, 116:263-271.
[26]	周亚运,肖军,吕潇,等.预处理生物质的热解实验研究[J].东南大学学报(自然科学版),2016,46(2):317-325.
	ZHOU Y Y, XIAO J, LYU X, et al.. Experimental study on pyrolysis of pretreated biomass [J]. J. Southeast Univ.(Nat. Sci.), 2016, 46(2):317-325.
[27]	宫聚辉,邵婷婷,路平,等.煤和沙柳的O₂/CO₂混合燃烧特性及相互作用研究[J].中国农业科技导报,2017,19(10):96-106.
	GONG J H, SHAO T T, LU P, et al.. Combustion characteristic and interaction of coal and Salix Psammophila under O₂/CO₂ atmosphere [J]. J. Agric. Sci. Technol., 2017, 19(10):96-106.
[28]	苏允泓,任菊荣,孙云娟,等.烘焙提升生物质燃料品质的研究[J].林产化学与工业,2023,43(2):27-35.
	SU Y H, REN J R, SUN Y J, et al.. Improving the quality of biofuel by torrefaction [J].Chem.Ind.For.Prod.,2023,43(2):27-35.
[29]	SETKIT N, LI X, YAO H, et al.. Torrefaction under mechanical pressure of 10-70 atMPa 250 ℃ and its effect on pyrolysis behaviours of Leucaena wood [J/OL].Bioresour.Technol., 2021, 338:125503 [2023-12-18]. .
[30]	LI X J, HAYASHI J I, LI C Z. FT-Raman spectroscopic study of the evolution of char structure during the pyrolysis of a Victorian brown coal [J]. Fuel, 2006, 85(12/13):1700-1707.