Different pressures and different durations of ultra-high pressure treatment were conducted for persimmon pulp after vacuum packing.The results showed that with the increase of pressure and extension of duration,the t...Different pressures and different durations of ultra-high pressure treatment were conducted for persimmon pulp after vacuum packing.The results showed that with the increase of pressure and extension of duration,the total number of bacteria in persimmon pulp decreased gradually.The treatment at 400 MPa for 15 min could meet the requirement of commercial sterility.After treatment,the color and the contents of soluble sugar,soluble solids and titratable acid of persimmon pulp were not changed significantly compared with the control group(P >0.05).The content of vitamin C in persimmon pulp declined gradually with the increase in pressure and time,with the maximum loss of 8.06% observed at 600 MPa for 20 min.Peroxidase( POD) activity also declined gradually with the increase of pressure and time.The activity of polyphenol oxidase( PPO) declined gradually with the increase of time,and increased first and then decreased with the increase of pressure.The content of polyphenols increased first and then decreased with the increase in pressure,and tended to increase overall with the increase in time.Under the treatment of 400 MPa for 20 min,the content of polyphenols reached the maximum.The antioxidant capacity of persimmon pulp after ultra-high pressure treatment was higher than that in the control group,but no significant differences were found among the treatment groups( P > 0.05).Compared with the control group,soluble tannin content was increased after ultra-high pressure treatment,but was far below the critical value for astringency(2 mg/g).In conclusion,ultra-high pressure treatment has only a slight effect on the sensory quality of persimmon pulp and can maintain its nutritional quality to a large extent and improve its antioxidant capacity.Moreover,ultra-high pressure treatment can eliminate astringency completely.展开更多
China Energy’s National Institute of Clean-and-Low-Carbon Energy(NICE)is developing a Power Plant Smart Management(PPSM)platform that employs digital-twin technology to undertake techno-economic modelling analysis on...China Energy’s National Institute of Clean-and-Low-Carbon Energy(NICE)is developing a Power Plant Smart Management(PPSM)platform that employs digital-twin technology to undertake techno-economic modelling analysis on China Energy’s existing coal-fired power-plant units and explore cost-effective solutions to improve those plant units’thermal efficiencies and operating performance.This paper presents a case study of PPSM on a 320-MWe coal-fired thermal power-plant unit,demonstrating how the digital-twin technology was employed to explore and analyse optimization solutions.Various optimization solutions and their cost-effectiveness were assessed using the digital-twin-modelling analysis;the results indicated the optimization solutions are expected to improve the plant unit’s operating efficiency and reduce its current electricity-generation coal consumption by up to 3.5 g/kWh standard coal equivalent(sce),worth annual fuel-cost savings of approximately 4 million RMB for a single unit or 8 million RMB for the two identical 320-MWe units that the power plant currently operates.The digital twin was also employed to assess the power-plant unit’s operating economics during both summer and winter.In summer,when the unit operates in electricity-generation-only mode,the unit’s operating thermal efficiency could drop by up to 6%points following the grid demand of load changes from 100%maximum continuous rating(MCR)down to 30% MCR,resulting in an~45 RMB/MWh increase of electricity-generation cost.In winter,when the unit operates in combined heat and power(CHP)cogeneration mode,for the same boiler load,the CHP operation increases the plant unit’s operating profit with increasing district-heating duty,although the relative profit gain from the CHP cogeneration could start to decrease when the district-heating steam-extraction flow increases to a certain point that varies depending on the market prices of heat and electricity,while the fuel cost was found to be equivalent to~50% of the unit’s total CHP income cogenerated from its electricity and district heat outputs.展开更多
基金Supported by Key Science and Technology Program of Shanxi Province(20130311032-3)Project of Shanxi Academy of Agricultural Sciences for Enhancing Independent Scientific and Technological Innovation Ability(2016zzcx-01)
文摘Different pressures and different durations of ultra-high pressure treatment were conducted for persimmon pulp after vacuum packing.The results showed that with the increase of pressure and extension of duration,the total number of bacteria in persimmon pulp decreased gradually.The treatment at 400 MPa for 15 min could meet the requirement of commercial sterility.After treatment,the color and the contents of soluble sugar,soluble solids and titratable acid of persimmon pulp were not changed significantly compared with the control group(P >0.05).The content of vitamin C in persimmon pulp declined gradually with the increase in pressure and time,with the maximum loss of 8.06% observed at 600 MPa for 20 min.Peroxidase( POD) activity also declined gradually with the increase of pressure and time.The activity of polyphenol oxidase( PPO) declined gradually with the increase of time,and increased first and then decreased with the increase of pressure.The content of polyphenols increased first and then decreased with the increase in pressure,and tended to increase overall with the increase in time.Under the treatment of 400 MPa for 20 min,the content of polyphenols reached the maximum.The antioxidant capacity of persimmon pulp after ultra-high pressure treatment was higher than that in the control group,but no significant differences were found among the treatment groups( P > 0.05).Compared with the control group,soluble tannin content was increased after ultra-high pressure treatment,but was far below the critical value for astringency(2 mg/g).In conclusion,ultra-high pressure treatment has only a slight effect on the sensory quality of persimmon pulp and can maintain its nutritional quality to a large extent and improve its antioxidant capacity.Moreover,ultra-high pressure treatment can eliminate astringency completely.
基金supported by the National Natural Science Foundation of China(Grant Nos.12102411,12072296,and 12072295)the Applied Basic Research Project of Sichuan Province(Grant No.2022NSFSC1957)+1 种基金the Research Funds from China Academy of Engineering Physics(Grant Nos.TCGH0414 and 2022YZL03)Fundamental Research Funds for Central Universities(Grant No.2682023CG004)。
文摘China Energy’s National Institute of Clean-and-Low-Carbon Energy(NICE)is developing a Power Plant Smart Management(PPSM)platform that employs digital-twin technology to undertake techno-economic modelling analysis on China Energy’s existing coal-fired power-plant units and explore cost-effective solutions to improve those plant units’thermal efficiencies and operating performance.This paper presents a case study of PPSM on a 320-MWe coal-fired thermal power-plant unit,demonstrating how the digital-twin technology was employed to explore and analyse optimization solutions.Various optimization solutions and their cost-effectiveness were assessed using the digital-twin-modelling analysis;the results indicated the optimization solutions are expected to improve the plant unit’s operating efficiency and reduce its current electricity-generation coal consumption by up to 3.5 g/kWh standard coal equivalent(sce),worth annual fuel-cost savings of approximately 4 million RMB for a single unit or 8 million RMB for the two identical 320-MWe units that the power plant currently operates.The digital twin was also employed to assess the power-plant unit’s operating economics during both summer and winter.In summer,when the unit operates in electricity-generation-only mode,the unit’s operating thermal efficiency could drop by up to 6%points following the grid demand of load changes from 100%maximum continuous rating(MCR)down to 30% MCR,resulting in an~45 RMB/MWh increase of electricity-generation cost.In winter,when the unit operates in combined heat and power(CHP)cogeneration mode,for the same boiler load,the CHP operation increases the plant unit’s operating profit with increasing district-heating duty,although the relative profit gain from the CHP cogeneration could start to decrease when the district-heating steam-extraction flow increases to a certain point that varies depending on the market prices of heat and electricity,while the fuel cost was found to be equivalent to~50% of the unit’s total CHP income cogenerated from its electricity and district heat outputs.
