Review of ethanol production via biological syngas fermentation

doi:10.11949/0438-1157.20220268

Abstract

Abstract:

Syngas bio-fermentation to produce ethanol has the advantages of mild reaction conditions, high product selectivity, wide source of raw materials, and low-carbon sustainable development. It is a promising new production process for renewable energy. The species of microorganisms and corresponding suitable operating conditions for ethanol production via syngas fermentation are reviewed. The Wood-Ljungdahl pathway of syngas fermentation is analyzed and the extensive sources of syngas are summarized. The effects of the process parameters, such as the composition of syngas, pressure, pH, temperature, medium component and gas-liquid mass transfer on syngas fermentation, are analyzed and discussed. The key problems of poor mass transfer performance of gas substrate and low ethanol yield in the syngas fermentation process are pointed out. The different mass transfer performance of typical bioreactors is compared, and the approaches to enhancing mass transfer are reviewed. Finally, the industrialization progress of ethanol production by syngas fermentation is reviewed, and the future development direction is proposed.

Key words: syngas, fermentation, ethanol, bioreactor, mass transfer

摘要：

采用合成气生物发酵法制乙醇具有反应条件温和、产物选择性高、原料来源广泛、低碳可持续发展等优势，是一种具有前景的可再生能源新型生产工艺。文章综述了合成气发酵法制乙醇的微生物种类及对应的适宜操作条件，分析了合成气发酵法制乙醇的Wood-Ljungdahl代谢途径；总结了合成气的广泛来源；分析讨论了过程工艺参数如合成气组成及压力、pH、温度、培养基组分、气液传质对合成气发酵的影响；指出合成气发酵法制乙醇面临的底物传质性能差、乙醇收率低等关键问题，比较了典型反应器在传质方面的差异，归纳了传质强化方法；总结了合成气发酵法制乙醇的工业化进展，并提出了未来的发展方向。

关键词: 合成气, 发酵, 乙醇, 生物反应器, 传质

CLC Number:

TQ 920.6

Yuelin WANG, Wei CHAO, Xiaocheng LAN, Zhipeng MO, Shuhuan TONG, Tiefeng WANG. Review of ethanol production via biological syngas fermentation[J]. CIESC Journal, 2022, 73(8): 3448-3460.

王悦琳, 晁伟, 蓝晓程, 莫志朋, 佟淑环, 王铁峰. 合成气生物发酵法制乙醇的研究进展[J]. 化工学报, 2022, 73(8): 3448-3460.

Figures/Tables 6

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菌种	分离来源	适宜温度/℃	适宜pH	产物
嗜中温菌种
Alkalibaculum bacchi^[8-9]	农场土壤	37	8.0~8.5	乙酸、乙醇
Acetobacterium woodi^[4]	—	30	6.8	乙酸
Butyribacterium methylotrophicum^[10-12]	下水道污泥	37~40	7.5	乙酸、乙醇、丁酸、丁醇
Clostridium aceticum^[13]	—	30	8.5	乙酸
Clostridium autoethanogenum^[14-15]	兔粪	37	5.8~6.0	乙醇、乙酸、2,3-丁二醇
Clostridium carboxidivorans^[16]	—	37	5.2	乙醇、丁醇
Clostridium carboxidivorans P7^[17]	污水池沉积物	38	5.0~7.0	乙酸、乙醇、丁醇
Clostridium coskatii^[18]	—	37	5.8~6.5	乙酸、乙醇
Clostridium drakei^[17]	沉积物	25~30	3.6~6.8	乙酸、乙醇、丁酸
Clostridium ljungdahlii^[19]	鸡粪	37	6.0	乙醇、乙酸
Clostridium ragsdalei P11^[20-21]	鸭塘底泥	37	6.3	乙醇
Clostridium scatologenes^[22]	—	37~40	5.4~7.0	乙酸、乙醇、丁酸
Mesophilic bacterium P7^[23]	农业潟湖	37	5.7~5.8	乙醇
嗜热菌种
Moorella sp. HUC22-1^[24]	地下热泥浆	55	6.3	乙酸
Moorella thermoautotrophica^[25]	—	58	6.1	乙酸

菌种	分离来源	适宜温度/℃	适宜pH	产物
嗜中温菌种
Alkalibaculum bacchi^[8-9]	农场土壤	37	8.0~8.5	乙酸、乙醇
Acetobacterium woodi^[4]	—	30	6.8	乙酸
Butyribacterium methylotrophicum^[10-12]	下水道污泥	37~40	7.5	乙酸、乙醇、丁酸、丁醇
Clostridium aceticum^[13]	—	30	8.5	乙酸
Clostridium autoethanogenum^[14-15]	兔粪	37	5.8~6.0	乙醇、乙酸、2,3-丁二醇
Clostridium carboxidivorans^[16]	—	37	5.2	乙醇、丁醇
Clostridium carboxidivorans P7^[17]	污水池沉积物	38	5.0~7.0	乙酸、乙醇、丁醇
Clostridium coskatii^[18]	—	37	5.8~6.5	乙酸、乙醇
Clostridium drakei^[17]	沉积物	25~30	3.6~6.8	乙酸、乙醇、丁酸
Clostridium ljungdahlii^[19]	鸡粪	37	6.0	乙醇、乙酸
Clostridium ragsdalei P11^[20-21]	鸭塘底泥	37	6.3	乙醇
Clostridium scatologenes^[22]	—	37~40	5.4~7.0	乙酸、乙醇、丁酸
Mesophilic bacterium P7^[23]	农业潟湖	37	5.7~5.8	乙醇
嗜热菌种
Moorella sp. HUC22-1^[24]	地下热泥浆	55	6.3	乙酸
Moorella thermoautotrophica^[25]	—	58	6.1	乙酸

合成气来源	CO/%	CO₂/%	H₂/%	N₂/%	CH₄/%
煤燃烧气化^[36]	31.8~38.5	1~6	48~66.5	0.4~6.4	0.3~0.5
天然气转化^[37]	17.5	11.6	63.6	5.7	0.9
木质纤维素气化^[38]	14.7	16.5	4.4	56.8	4.2

合成气来源	CO/%	CO₂/%	H₂/%	N₂/%	CH₄/%
煤燃烧气化^[36]	31.8~38.5	1~6	48~66.5	0.4~6.4	0.3~0.5
天然气转化^[37]	17.5	11.6	63.6	5.7	0.9
木质纤维素气化^[38]	14.7	16.5	4.4	56.8	4.2

工业尾气类型	CO/%	CO₂/%	H₂/%	N₂/%	CH₄/%
电石炉尾气	78.97	3.22	6.96	10.34	0.013
碳化硅尾气	70~90	2~3	1~5	1~3	2~4
黄磷尾气	75~85	0.4	10~15	—	4
醋酸尾气	81	3	12	2	1.5
铁合金尾气	65~75	10~15	5~10	5~10	0~2
转炉煤气	60~80	15~22	0~2.5	10~20	—
合成氨驰放气	25~45	—	2.5~8	41~64	—
高炉煤气	25~30	9~12	1.5~3	55~60	—
炭黑尾气	9~13	2~3	9~12	36~38	0.2~0.8
焦炉煤气	5.5~7	1~3	54~59	3~5	25~30