Chinese forests, characterized by relatively young stand age, represent a significant biomass carbon （C） sink over the past several decades. Nevertheless, it is unclear how forest biomass C sequestration capacity in...Chinese forests, characterized by relatively young stand age, represent a significant biomass carbon （C） sink over the past several decades. Nevertheless, it is unclear how forest biomass C sequestration capacity in China will evolve as forest age, climate and atmospheric CO2 concentration change continuously. Here, we present a semi-empirical model that incorporates forest age and climatic factors for each lbrest type to estimate the effects of forest age and climate change on total forest biomass, under three different sce-narios based on the fifth phase of the Coupled Model Intercomparison Project （CMIPS）. We estimate that age-related forest biomass C sequestration to be 6.69 Pg C （~0.17 Pg C a^-1） from the 2000s to the 2040s. Climate change induces a rather weak increase in total forest biomass C sequestration （0.52-0.60 Pg C by tile 2040s）. We show that rising CO2 concentrations could further increase tile total forest biomass C sequestration by 1.68-3.12 Pg C in the 2040s across all three scenarios. Overall, the total forest biomass in China would increase by 8.89-10.37 Pg C by the end of 2040s. Our findings highlight the benefits of Chinese afforestation programs, continued climate change and increasing CO2. concentration in sustaining the forest biomass C sink in the near future, and could therefore be useful for designing more realistic climate change mitigation policies such as continuous forestation programs and careful choice of tree species.展开更多
The conversion of biomass into hydrogen-rich gas provides a competitive means for producing clean energy and chemicals from renewable resources.Based on the principle of Gibbs free energy minimization, a new method wa...The conversion of biomass into hydrogen-rich gas provides a competitive means for producing clean energy and chemicals from renewable resources.Based on the principle of Gibbs free energy minimization, a new method was presented with better effectiveness and simplicity to be used for the prediction of chemical equilibrium composition of hydrogen production by biomass gasification in supercritical water(SCW).Applying this method to analyzing the process of glucose gasification in SCW, it was found that the product gas consisted primarily of hydrogen and carbon dioxide as well as a small amount of methane and carbon monoxide.The gas yield was strongly affected by reaction temperature and feedstock concentration and less affected by reaction pressure in the following range:temperature 623—1073 K,pressure 22.5—35 MPa,and concentration 0.1—0.8 mol·L -1 .The hydrogen production in product gas increased with the increase of temperature and decreased with the increase of concentration.展开更多
基金supported by the National Key R&D Program of China(2017YFA0604702)the National Natural Science Foundation of China(41530528 and 31621091)
文摘Chinese forests, characterized by relatively young stand age, represent a significant biomass carbon （C） sink over the past several decades. Nevertheless, it is unclear how forest biomass C sequestration capacity in China will evolve as forest age, climate and atmospheric CO2 concentration change continuously. Here, we present a semi-empirical model that incorporates forest age and climatic factors for each lbrest type to estimate the effects of forest age and climate change on total forest biomass, under three different sce-narios based on the fifth phase of the Coupled Model Intercomparison Project （CMIPS）. We estimate that age-related forest biomass C sequestration to be 6.69 Pg C （~0.17 Pg C a^-1） from the 2000s to the 2040s. Climate change induces a rather weak increase in total forest biomass C sequestration （0.52-0.60 Pg C by tile 2040s）. We show that rising CO2 concentrations could further increase tile total forest biomass C sequestration by 1.68-3.12 Pg C in the 2040s across all three scenarios. Overall, the total forest biomass in China would increase by 8.89-10.37 Pg C by the end of 2040s. Our findings highlight the benefits of Chinese afforestation programs, continued climate change and increasing CO2. concentration in sustaining the forest biomass C sink in the near future, and could therefore be useful for designing more realistic climate change mitigation policies such as continuous forestation programs and careful choice of tree species.
文摘The conversion of biomass into hydrogen-rich gas provides a competitive means for producing clean energy and chemicals from renewable resources.Based on the principle of Gibbs free energy minimization, a new method was presented with better effectiveness and simplicity to be used for the prediction of chemical equilibrium composition of hydrogen production by biomass gasification in supercritical water(SCW).Applying this method to analyzing the process of glucose gasification in SCW, it was found that the product gas consisted primarily of hydrogen and carbon dioxide as well as a small amount of methane and carbon monoxide.The gas yield was strongly affected by reaction temperature and feedstock concentration and less affected by reaction pressure in the following range:temperature 623—1073 K,pressure 22.5—35 MPa,and concentration 0.1—0.8 mol·L -1 .The hydrogen production in product gas increased with the increase of temperature and decreased with the increase of concentration.
