A critical pathway towards enhancing pulp mill biorefineries is to integrate the extraction and utilization of hemicelluloses into the pulping processes.Hence,an industrial pre-extraction strategy for hemicelluloses t...A critical pathway towards enhancing pulp mill biorefineries is to integrate the extraction and utilization of hemicelluloses into the pulping processes.Hence,an industrial pre-extraction strategy for hemicelluloses targeting eucalyptus kraft pulping process was developed.Alkaline solution or pulping white liquor was used to pre-extract hemicelluloses before the actual pulping process.The response surface methodology(RSM)technique was applied to investigate the most suitable conditions to maximize the yield of these hemicelluloses while simultaneously minimizing the damage to pulp yields and properties.Temperature(105 to 155℃),alkali concentration(3%to 8%),sulfidity(20%to 30%)and retention time(19 to 221 min)were combined to evaluate their effects on hemicellulose yields and chemical structures.The optimal pre-extraction conditions identified in this work(5.75%NaOH concentration,25%sulfidity at 135℃for 60 min)successfully allowed recovering 4.8%of hemicelluloses(based on the wood dry mass)and limited damages to pulp yields and properties.The cellulose content in pulp can even be increased by about 10%.Hemicellulose emulsification properties were also evaluated,which were comparable to synthetic emulsifiers.This study provides an industrial pathway to effectively separate and utilize wood hemicelluloses from the pulping process,which has the potential to improve the economy and material utilization of pulp and paper mills.展开更多
呼和浩特盛乐现代服务业集聚区云计算数据中心由内蒙古京能盛乐热电公司的冷热电三联供机组提供冷源,制冷站一期负荷为17 585 k W。同过分析比较,制冷站选用溴化锂吸收式制冷机,并拟定4种制冷方案。经分析认为,全部采用热水吸收式制冷方...呼和浩特盛乐现代服务业集聚区云计算数据中心由内蒙古京能盛乐热电公司的冷热电三联供机组提供冷源,制冷站一期负荷为17 585 k W。同过分析比较,制冷站选用溴化锂吸收式制冷机,并拟定4种制冷方案。经分析认为,全部采用热水吸收式制冷方案,虽然初投资及运行费用较大,但该方案可实现能源的阶梯利用,热效率可达80%以上;可填补热电机组夏季热负荷的低谷,均衡热电机组冬、夏季用汽负荷;可以提高云计算数据中心的安全性和可靠性,降低设备的维护工作量及费用;在运行中可以减少机组耗煤量,从而减少污染物排放量。因此该云计算数据中心采用热水吸收式制冷方案。展开更多
基金supported by the Natural Science Foundation of Guangdong Province(2023A1515030211)the National Natural Science Foundation of China(22278157)Guangzhou Science and Technology Program(2023B03J1365).
文摘A critical pathway towards enhancing pulp mill biorefineries is to integrate the extraction and utilization of hemicelluloses into the pulping processes.Hence,an industrial pre-extraction strategy for hemicelluloses targeting eucalyptus kraft pulping process was developed.Alkaline solution or pulping white liquor was used to pre-extract hemicelluloses before the actual pulping process.The response surface methodology(RSM)technique was applied to investigate the most suitable conditions to maximize the yield of these hemicelluloses while simultaneously minimizing the damage to pulp yields and properties.Temperature(105 to 155℃),alkali concentration(3%to 8%),sulfidity(20%to 30%)and retention time(19 to 221 min)were combined to evaluate their effects on hemicellulose yields and chemical structures.The optimal pre-extraction conditions identified in this work(5.75%NaOH concentration,25%sulfidity at 135℃for 60 min)successfully allowed recovering 4.8%of hemicelluloses(based on the wood dry mass)and limited damages to pulp yields and properties.The cellulose content in pulp can even be increased by about 10%.Hemicellulose emulsification properties were also evaluated,which were comparable to synthetic emulsifiers.This study provides an industrial pathway to effectively separate and utilize wood hemicelluloses from the pulping process,which has the potential to improve the economy and material utilization of pulp and paper mills.
文摘呼和浩特盛乐现代服务业集聚区云计算数据中心由内蒙古京能盛乐热电公司的冷热电三联供机组提供冷源,制冷站一期负荷为17 585 k W。同过分析比较,制冷站选用溴化锂吸收式制冷机,并拟定4种制冷方案。经分析认为,全部采用热水吸收式制冷方案,虽然初投资及运行费用较大,但该方案可实现能源的阶梯利用,热效率可达80%以上;可填补热电机组夏季热负荷的低谷,均衡热电机组冬、夏季用汽负荷;可以提高云计算数据中心的安全性和可靠性,降低设备的维护工作量及费用;在运行中可以减少机组耗煤量,从而减少污染物排放量。因此该云计算数据中心采用热水吸收式制冷方案。
