Gas-pressurized torrefaction of biomass: A review

doi:10.16085/j.issn.1000-6613.2023-2126

Abstract

Abstract:

Gas-pressurized (GP) torrefaction has the advantages of mild reaction conditions, low energy consumption, high deoxygenation efficiency, high energy recovery efficiency, and semi-coke fuel quality similar as subbitumiunous coal. It is one of the novel technologies promising to replace the traditional torrefaction. This review introduces the development of GP torrefaction, reviews the optimization of GP torrefaction conditions (including the raw biomass type, temperature, pressure and time) and product composition and physicochemical properties, explains the macroscopic reaction pathways and microscopic reaction mechanisms, focuses on the combustion, pyrolysis and gasification utilisation pathways of semi-coke, reviews the reactor design and expansion in solid waste treatment such as chlorinated solid waste, sludge, etc. Finally, the GP torrefaction technology converting biomass into high fuel quality solid fuel which can directly replace coal is summarised and prospected.

Key words: biomass, gas-pressurized torrefaction, deoxygenation, optimization, product characteristics

摘要：

气压烘焙技术具备反应条件温和、能耗低、脱氧效率高、能量回收率高、半焦燃料品质近似次烟煤等优势，是一种有希望替代传统烘焙的新型技术之一。本文介绍了气压烘焙的发展脉络，综述了气压烘焙工况优化（包括原料种类、温度、压力、时间）、产物组成与理化特性，阐述了气压烘焙宏观反应路径和微观反应机理，着重介绍了半焦的燃烧、热解、气化利用途径，回顾了气压烘焙的反应器设计及其在含氯固废、污泥等处置中的拓展。最后对气压烘焙技术可将生物质转化为高品质固体燃料，直接替代煤炭进行了总结和展望。

关键词: 生物质, 气压烘焙, 脱氧, 优化, 产物特性

CLC Number:

SHI Liu, HU Zhenzhong, LI Xian, SUN Yiming, TONG Shan, LIU Xianzhe, GUO Li, LIU Hao, PENG Bing, LI Shuo, LUO Guangqian, YAO Hong. Gas-pressurized torrefaction of biomass: A review[J]. Chemical Industry and Engineering Progress, 2024, 43(5): 2494-2511.

石鎏, 胡振中, 李显, 孙一鸣, 童珊, 刘显哲, 郭丽, 刘豪, 彭冰, 李硕, 罗光前, 姚洪. 生物质气压烘焙技术研究进展[J]. 化工进展, 2024, 43(5): 2494-2511.

Figures/Tables 33

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项目	常压烘焙	气压烘焙
条件	250~300℃	200~250℃
	常压	1~1.8MPa
	10~120min	15~60min
机制	热裂解反应	强化挥发分与生物质的二次反应
能耗	高	低
半焦品质	氧含量>30%；高位热值17~24MJ/kg	氧含量约20%；高位热值23~28MJ/kg
	能量回收率70%~95%	能量回收率85%~96%
	可磨性好	可磨性好
	燃料品质近似泥煤	燃料品质近似次烟煤

项目	常压烘焙	气压烘焙
条件	250~300℃	200~250℃
	常压	1~1.8MPa
	10~120min	15~60min
机制	热裂解反应	强化挥发分与生物质的二次反应
能耗	高	低
半焦品质	氧含量>30%；高位热值17~24MJ/kg	氧含量约20%；高位热值23~28MJ/kg
	能量回收率70%~95%	能量回收率85%~96%
	可磨性好	可磨性好
	燃料品质近似泥煤	燃料品质近似次烟煤

种类	样品	烘焙条件	工业分析（d.b.）/%			元素分析（d.a.f.）/%				高位热值（d.a.f.） /MJ·kg^-1
种类	样品	烘焙条件	挥发分	固定碳	灰分	C	H	N	O	高位热值（d.a.f.） /MJ·kg^-1
农业生物质	稻秆1^[36]		75.2	15.2	9.6	48.9	5.2	0.9	45.0	15.9
		250℃、15min常压烘焙	68.8	19.9	11.3	50.8	5.6	1.0	42.7	17.5
		250℃、2.5MPa、15min气压烘焙	40.8	40.5	18.7	68.4	5.2	1.5	24.9	26.2
	稻秆2^[28]		75.2	15.1	9.7	45.8	6.0	1.1	47.1	15.7
		250℃、60min常压烘焙	72.1	15.9	12.1	53.2	6.0	1.3	39.5	19.7
		250℃、1.8MPa、60min气压烘焙	45.9	36.0	18.2	70.8	5.5	1.9	21.8	28.0
	玉米秸秆^[37]		72.7	19.6	7.7	43.7	5.3	2.8	48.2	17.6
		250℃、30min常压烘焙	66.6	22.3	11.1	45.4	4.9	2.3	47.4	18.2
		250℃、2.5MPa N₂、30min气压烘焙	49.5	35.7	14.8	56.7	4.5	2.5	36.3	22.2
	芦苇^[38]		70.0	18.1	11.9	44.5	5.7	1.7	48.1	14.6
		270℃、30min常压烘焙	35.3	47.0	17.7	51.4	5.1	2.1	41.4	17.3
		270℃、2.5MPa N₂、30min气压烘焙	30.9	43.4	25.7	59.6	4.0	3.0	33.4	19.9
林业生物质	松木1^[39]		85.5	14.1	0.4	50.3	5.9	0.04	43.8	17.7
		250℃、15min常压烘焙	82.5	17.0	0.5	53.3	6.0	0.03	40.6	19.4
		250℃、2.5MPa N₂、15min气压烘焙	62.1	37.1	0.8	65.4	5.5	0.09	29.1	24.7
	松木2		80.6	16.9	2.5	47.9	5.6	0.2	46.3	16.9
		250℃、60min常压烘焙	75.0	21.0	3.1	51.9	5.5	0.2	42.4	18.7
		250℃、1.8MPa、60min气压烘焙	43.0	53.6	3.4	71.3	4.7	0.3	23.7	27.0
	银合欢^[21]		87.3	12.2	0.5	50.1	7.4	0.7	41.8	20.4
		250℃、30min常压烘焙	81.6	17.3	1.1	54.0	6.4	0.7	38.9	21.9
		250℃、4.0MPa、30min气压烘焙	60.0	38.2	1.8	62.3	5.6	1.0	31.1	25.8
	杨木^[37]		84.0	15.1	0.9	49.2	5.5	0.8	43.5	19.5
		250℃、30min常压烘焙	82.9	15.6	1.5	49.8	5.7	0.8	43.7	19.8
		250℃、2.5MPa N₂、30min气压烘焙	71.2	26.9	1.8	58.4	5.6	0.5	35.4	23.5

种类	样品	烘焙条件	工业分析（d.b.）/%			元素分析（d.a.f.）/%				高位热值（d.a.f.） /MJ·kg^-1
种类	样品	烘焙条件	挥发分	固定碳	灰分	C	H	N	O	高位热值（d.a.f.） /MJ·kg^-1
农业生物质	稻秆1^[36]		75.2	15.2	9.6	48.9	5.2	0.9	45.0	15.9
		250℃、15min常压烘焙	68.8	19.9	11.3	50.8	5.6	1.0	42.7	17.5
		250℃、2.5MPa、15min气压烘焙	40.8	40.5	18.7	68.4	5.2	1.5	24.9	26.2
	稻秆2^[28]		75.2	15.1	9.7	45.8	6.0	1.1	47.1	15.7
		250℃、60min常压烘焙	72.1	15.9	12.1	53.2	6.0	1.3	39.5	19.7
		250℃、1.8MPa、60min气压烘焙	45.9	36.0	18.2	70.8	5.5	1.9	21.8	28.0
	玉米秸秆^[37]		72.7	19.6	7.7	43.7	5.3	2.8	48.2	17.6
		250℃、30min常压烘焙	66.6	22.3	11.1	45.4	4.9	2.3	47.4	18.2
		250℃、2.5MPa N₂、30min气压烘焙	49.5	35.7	14.8	56.7	4.5	2.5	36.3	22.2
	芦苇^[38]		70.0	18.1	11.9	44.5	5.7	1.7	48.1	14.6
		270℃、30min常压烘焙	35.3	47.0	17.7	51.4	5.1	2.1	41.4	17.3
		270℃、2.5MPa N₂、30min气压烘焙	30.9	43.4	25.7	59.6	4.0	3.0	33.4	19.9
林业生物质	松木1^[39]		85.5	14.1	0.4	50.3	5.9	0.04	43.8	17.7
		250℃、15min常压烘焙	82.5	17.0	0.5	53.3	6.0	0.03	40.6	19.4
		250℃、2.5MPa N₂、15min气压烘焙	62.1	37.1	0.8	65.4	5.5	0.09	29.1	24.7
	松木2		80.6	16.9	2.5	47.9	5.6	0.2	46.3	16.9
		250℃、60min常压烘焙	75.0	21.0	3.1	51.9	5.5	0.2	42.4	18.7
		250℃、1.8MPa、60min气压烘焙	43.0	53.6	3.4	71.3	4.7	0.3	23.7	27.0
	银合欢^[21]		87.3	12.2	0.5	50.1	7.4	0.7	41.8	20.4
		250℃、30min常压烘焙	81.6	17.3	1.1	54.0	6.4	0.7	38.9	21.9
		250℃、4.0MPa、30min气压烘焙	60.0	38.2	1.8	62.3	5.6	1.0	31.1	25.8
	杨木^[37]		84.0	15.1	0.9	49.2	5.5	0.8	43.5	19.5
		250℃、30min常压烘焙	82.9	15.6	1.5	49.8	5.7	0.8	43.7	19.8
		250℃、2.5MPa N₂、30min气压烘焙	71.2	26.9	1.8	58.4	5.6	0.5	35.4	23.5

样品	工业分析（d.b.）/%			元素分析（d.a.f.）/%				高位热值（d.a.f.） /MJ·kg^-1
样品	挥发分	固定碳（diff.）	灰分	C	H	N	O（diff.）	高位热值（d.a.f.） /MJ·kg^-1
稻秆	75.2	15.2	9.6	48.9	5.2	0.9	45.0	15.9
AP-200	74.3	15.5	10.2	47.5	6.0	0.9	45.6	16.5
AP-250	68.8	19.9	11.3	50.8	5.6	1.0	42.7	17.5
AP-300	43.0	35.5	21.5	65.3	5.0	1.3	28.4	24.1
GP-200	49.8	33.8	16.4	61.0	5.6	1.3	32.1	22.8
GP-250	40.8	40.5	18.7	68.4	5.2	1.5	24.9	26.2
GP-300	30.6	47.5	21.9	73.2	5.1	1.6	20.0	28.6
褐煤	45.3	34.2	20.5	65.3	4.9	1.1	28.7	24.0
次烟煤	33.2	44.3	22.5	74.9	5.7	1.5	17.9	31.7