In recent years, there has been global interest in meeting targets relating to energy affordability and security while taking into account greenhouse gas emissions. This has heightened major interest in potential inve...In recent years, there has been global interest in meeting targets relating to energy affordability and security while taking into account greenhouse gas emissions. This has heightened major interest in potential investigations into the use of supercritical carbon dioxide (sCO2) power cycles. Climate change mitigation is the ultimate driver for this increased interest;other relevant issues include the potential for high cycle efficiency and a circular economy. In this study, a 25 MWe recompression closed Brayton cycle (RCBC) has been assessed, and sCO2 has been proposed as the working fluid for the power plant. The methodology used in this research work comprises thermodynamic and techno-economic analysis for the prospective commercialization of this sCO2 power cycle. An evaluated estimation of capital expenditure, operational expenditure, and cost of electricity has been considered in this study. The ASPEN Plus simulation results have been compared with theoretical and mathematical calculations to assess the performance of the compressors, turbine, and heat exchangers. The results thus reveal that the cycle efficiency for this prospective sCO2 recompression closed Brayton cycle increases (39% - 53.6%) as the temperature progressively increases from 550˚C to 900˚C. Data from the Aspen simulation model was used to aid the cost function calculations to estimate the total capital investment cost of the plant. Also, the techno-economic results have shown less cost for purchasing equipment due to fewer components being required for the cycle configuration as compared to the conventional steam power plant.展开更多
Transition toward a sustainable,low-carbon energy future requires innovative,integrated solutions.Hybrid solar-hydrogen systems(HSHSs),which combine solar energy harvesting and hydrogen production,have excellent prose...Transition toward a sustainable,low-carbon energy future requires innovative,integrated solutions.Hybrid solar-hydrogen systems(HSHSs),which combine solar energy harvesting and hydrogen production,have excellent prosepects to address challenges related to renewable energy generation,storage,and usage.This article presents an overview of the research on the technical and economic feasibility of HSHSs,aimed at comprehensively articulating their current state,notable advancements,and future research directions.It begins by elucidating solar energy principles and conversion methods and emphasizing the potential of solar energy for hydrogen production.This study then explores the definitions,components,and synergistic integration of HSHSs.Optimized energy conversion and storage methods for efficient hydrogen production and storage are also highlighted.This study reviews the techniques employed for techno-economic evaluations over the last six years,addressing challenges such as the intermittency of solar energy and the efficiency of hydrogen production technologies.This review of the ongoing research provides helpful insights into the technological and economic feasibility of HSHSs.This underscores the necessity of continuous research and development efforts to overcome existing challenges and unlock their full potential.These systems can play a vital role in achieving a cleaner and more resilient energy future by optimizing the system performance,reducing costs,and fostering supportive policy frameworks.展开更多
The natural gas(NG)reforming is currently one of the low-cost methods for hydrogen production.However,the mixture of H2 and CO_(2) in the produced gas inevitably includes CO_(2) and necessitates the costly CO_(2) sepa...The natural gas(NG)reforming is currently one of the low-cost methods for hydrogen production.However,the mixture of H2 and CO_(2) in the produced gas inevitably includes CO_(2) and necessitates the costly CO_(2) separation.In this work,a novel double chemical looping involving both combustion(CLC)and sorption-enhanced reforming(SE-CLR)was proposed towards the co-production of H2 and CO(CLC-SECLRHC)in two separated streams.CLC provides reactant CO_(2) and energy to feed SECLRHC,which generates hydrogen in a higher purity,as well as the calcium cycle to generate CO in a higher purity.Techno-economic assessment of the proposed system was conducted to evaluate its efficiency and economic competitiveness.Studies revealed that the optimal molar ratios of oxygen carrier(OC)/NG and steam/NG for reforming were recommended to be 1.7 and 1.0,respectively.The heat integration within CLC and SECLRHC units can be achieved by circulating hot OCs.The desired temperatures of fuel reactor(FR)and reforming reactor(RR)should be 850C and 600C,respectively.The heat coupling between CLC and SECLRHC units can be realized via a jacket-type reactor,and the NG split ratio for reforming and combustion was 0.53:0.47.Under the optimal conditions,the H2 purity,the H2 yield and the CH4 conversion efficiency were 98.76%,2.31 mol mol-1 and 97.96%,respectively.The carbon and hydrogen utilization efficiency respectively were 58.60% and 72.45%in terms of the total hydrogen in both steam and NG.The exergy efficiency of the overall process reached 70.28%.In terms of the conventional plant capacity(75 × 103 t y^(-1))and current raw materials price(2500$t^(-1)),the payback period can be 6.2 years and the IRR would be 11.5,demonstrating an economically feasible and risk resistant capability.展开更多
On the basis of practical projects in Chongqing,the thermal performance of heat exchangers (single U-tube type and double U-tube type) of the ground-source heat pump (GSHP) system in the hot summer was obtained and an...On the basis of practical projects in Chongqing,the thermal performance of heat exchangers (single U-tube type and double U-tube type) of the ground-source heat pump (GSHP) system in the hot summer was obtained and analyzed. The data obtained from test could match with the result deduced from theoretical calculation. From the test results,the cooling capacity of double U-tube is 1.6 times that of single U-tube. Taking cost per depth per watt Clq as the evaluation standard,Clq of single U-tube is 4.69 RMB$/W,and Clq of double U-tube is 3.14 RMB$/W. The double U-tube heat exchangers usage should be prioritized.展开更多
The integration of refinery and petrochemical units(IRPUs)has become an inevitable choice for the sustainable development of petrochemical industry.The utilization efficiency of petroleum resources could be improved o...The integration of refinery and petrochemical units(IRPUs)has become an inevitable choice for the sustainable development of petrochemical industry.The utilization efficiency of petroleum resources could be improved obviously through IRPUs.However,integrating economic and environmental impacts into the model of IRPUs is still a grand challenge.Herein,a model called TEA-GHG-OPWM(Techno-Economic Analysis and GreenHouse Gases Oriented Plant-Wide Model)has been established on Aspen HYSYSTM platform to calculate the energy consumption,the technoeconomic performance,and the GHG emissions for two different kinds of schemes,viz,:VRHCU(Vacuum Residue Hydrocracking Unit)and VRDS-RFCC(Vacuum Residue Desulfurization and Residue Fluid Catalytic Cracking).Furthermore,a novel processing pathway named VGOHDT-HTMP-DC(Vacuum Gas Oil Hydrotreating,Hydrogenation and TMP coupling process and Delayed Coking)has also been developed to find methods to improve the economic performance based on a ten-million-CNY output value(TMYOV)and a reduced GHG emissions.Our results demonstrate that VRHCRU could consume more energy and emit more GHG(877.11 t of CO2 eq·TMYOV^-1·h^-1)than VRDS-RFCC(817.03 t of CO2 eq·TMYOV^-1·h^-1)and VGOHDT-HTMP-DC(721.96 t of CO2 eq·TMYOV^-1·h^-1),while obtaining a higher mass yield of petrochemicals.The VGOHDT-HTMP-DC process exhibits the lowest feedstock consumption,hydrogen consumption,energy consumption,and GHG emissions,indicating that VGOHDT-HTMP-DC has both well economic and environmentally friendly performance.展开更多
Process algorithm, numerical model and techno-economic assessment of charge calculation and furnace bath optimization for target alloy for induction furnace-based steelmaking is presented in this study. The developed ...Process algorithm, numerical model and techno-economic assessment of charge calculation and furnace bath optimization for target alloy for induction furnace-based steelmaking is presented in this study. The developed algorithm combines the make-to-order (MTO) and charge optimization planning (COP) of the steel melting shop in the production of target steel composition. Using a system-level approach, the unit operations involved in the melting process were analyzed with the purpose of initial charge calculation, prevailing alloy charge prediction and optimizing the sequence of melt chemistry modification. The model performance was established using real-time production data from a cast iron-based foundry with a 1- and 2-ton induction furnace capacity and a medium carbon-based foundry with a 10- and 15-ton induction furnace capacity. A simulation engine (CastMELT) was developed in Java IDE with a MySQL database for continuous interaction with changing process parameters to run the model for validation. The comparison between the model prediction and production results was analyzed for charge prediction, melt modification and ferroalloy optimization and possible cost savings. The model performance for elemental charge prediction and calculation purpose with respect to the charge input (at overall scrap meltdown) gave R-squared, Standard Error, Pearson correlation and Significance value of (0.934, 0.06, 0.97, 0.0003) for Carbon prediction, (0.962, 0.06, 0.98, 0.00009) for Silicon prediction, (0.999, 0.048, 0.999, 9E -11) for Manganese Prediction, and (0.997, 0.076, 0.999, 6E -7) for Chromium prediction respectively. Correlation analysis for melt modification (after charging of ferroalloy) using the model for after-alloying spark analysis compared with the target chemistry is at 99.82%. The results validate the suitability of the developed model as a functional system of induction furnace melting for combined charge calculation and melt optimization Techno-economic evaluation results showed that 0.98% - 0.25% ferroalloy saving per ton of melt is possible using the model. This brings about an annual production cost savings of 100,000 $/y in foundry A (medium carbon steel) and 20,000 $/y in foundry B (cast iron) on the use of different ferroalloy materials.展开更多
With the rapid depletion of fossil fuel reserves, it is feared that the world will soon run out of its energy resources. This is a matter of concern for developing countries whose economy heavily leans on its use of e...With the rapid depletion of fossil fuel reserves, it is feared that the world will soon run out of its energy resources. This is a matter of concern for developing countries whose economy heavily leans on its use of energy. Under the circums-tances it is highly desirable that renewable energy resources should be utilized with maximum conversion efficiency to cope with the ever increasing energy demand. Furthermore, the global economic and political conditions that tend to make countries more dependent on their own energy resources have caused growing interest in the development and use of renewable energy based technologies. In terms of its environmental advantages, renewable energy sources generate electricity with insignificant contribution of carbon dioxide (CO2) or other greenhouse gases (GHG) to the atmosphere and they produce no pollutant discharge on water or soil and hence power generation from renewable becomes very important. Major types of renewable energy sources include solar, wind, hydro and biomass, all of which have huge potential to meet future energy challenges. Solar photovoltaic technology in one of the first among several renewable energy technologies that have been adopted worldwide for meeting the basic needs of electricity particularly in remote areas. In this paper literature review pertaining to techno-economic feasibility analysis of solar photovoltaic power generation is discussed. The literature is basically classified into the following three main category design methods, techno-economic feasibility of solar photovoltaic power generation, performance evaluations of various systems.展开更多
Energy recovery from waste biomass can have significant impacts on the most pressing development challenges of rural poverty and environmental damages. In this paper, a techno-economic analysis is carried out for elec...Energy recovery from waste biomass can have significant impacts on the most pressing development challenges of rural poverty and environmental damages. In this paper, a techno-economic analysis is carried out for electricity generation by using timber and wood waste (T & WW) gasification in Iceland. Different expenses were considered, like capital, installation, engineering, operation and maintenance costs and the interest rate of the investment. Regarding to revenues, they come from of the electricity sale and the fee paid by the Icelandic municipalities for waste collection and disposal. The economic feasibility was conducted based on the economic indicators of net present value (NPV) and discounted payback period (DPP), bringing together three different subgroups based on gasifier capacities, subgroup a: 50 kW, subgroup b: 100 kW and subgroup c: 200 kW. The results show that total cost increases as the implemented power is increased. This indicator varies from 1228.6 k€ for subgroups a to 1334.7 k€ for subgroups b and 1479.5 k€ for subgroups c. It is worth mentioning that NPV is positive for three subgroups and it grows as gasifier scale is extended. NPV is about 122 k€ (111,020 $), 1824 k€ (1,659,840 $) and 4392 k€ (3,996,720 $) for subgroups a, b and c, respectively. Moreover, DPP has an inversely proportional to the installed capacity. It is around 5.5 years (subgroups a), 9.5 months (subgroups b) and 6 months (subgroups c). The obtained results confirm that using small scale waste biomass gasification integrated with power generation could be techno-economically feasible for remote area in Iceland.展开更多
Over time,physical activity(PA)has shifted from being a necessity to being an alternative.As a result,levels of PA have sharply decreased.1 Today,we are facing a worldwide pandemic of physical inactivity,with one deat...Over time,physical activity(PA)has shifted from being a necessity to being an alternative.As a result,levels of PA have sharply decreased.1 Today,we are facing a worldwide pandemic of physical inactivity,with one death every 6 s attributed to insufficient PA.2 To counteract this trend,a tremendous effort is being made to promote regular PA across the lifespan,mainly through the dissemination of knowledge about the health benefits of accumulating sufficient PA.展开更多
A shift to renewable energy sources will reduce emissions of greenhouse gases and secure future energy supplies. In this context, utilization of biogas will play a prominent role. Focus of this work is upgrading of bi...A shift to renewable energy sources will reduce emissions of greenhouse gases and secure future energy supplies. In this context, utilization of biogas will play a prominent role. Focus of this work is upgrading of biogas to fuel quality by membrane separation using a carbon hollow fibre(CHF) membrane and compare with a commercially available polymeric membrane(polyimide) through economical assessment. CHF membrane modules were prepared for pilot plant testing and performance measured using CO_2, O_2, N_2. The CHF membrane was modified through oxidation, chemical vapour deposition(CVD) and reduction process thus tailoring pores for separation and increased performance. The post oxidized and reduced carbon hollow fibres(PORCHFs) significantly exceeded CHF performance showing higher CO_2 permeance(0.021 m^3(STP)/m^2 h bar) and CO_2/CH_4 selectivity of 246(5 bar feed vs 50 mbar permeate pressure). The highest performance recorded through experiments(CHF and PORCHF) was used as simulation basis. A membrane simulation model was used and interfaced to 8.6 V Aspen HYSYS.A 300 Nm^3/h mixture of CO_2/CH_4 containing 30-50% CO_2 at feed pressures 6, 8 and 10 bar, was simulated and process designed to recover99.5% CH_4 with 97.5% purity. Net present value(NPV) was calculated for base case and optimal pressure(50 bar for CHF and PORCHF). The results indicated that recycle ratio(recycle/feed) ranged from 0.2 to 10, specific energy from 0.15 to 0.8(kW/Nm^3 feed) and specific membrane area from 45 to 4700(m^2/Nm^3 feed). The high recycle ratio can create problems during start-up, as it would take long to adjust volumetric flow ratio towards 10. The best membrane separation system employs a three-stage system with polyimide at 10 bar, and a two-stage membrane system with PORCHF membranes at 50 bar with recycle. Considering biomethane price of 0.78 $/Nm^3 and a lifetime of 15 years, the technoeconomic analysis showed that payback time for the best cascade is 1.6 months.展开更多
Investigation of a triple-pressure organic Rankine cycle(TPORC) using geothermal energy for power generation with the net power output of the TPORC analyzed by varying the evaporation pressures, pinch temperature diff...Investigation of a triple-pressure organic Rankine cycle(TPORC) using geothermal energy for power generation with the net power output of the TPORC analyzed by varying the evaporation pressures, pinch temperature differences(tpp) and degrees of superheat(tsup) aimed to find the optimum operation conditions of the system. The thermodynamic performance of the TPORC was compared with a dual-pressure organic Rankine cycle(DPORC) and a single-pressure ORC(SPORC) for geofluid temperatures ranging from 100°C to 200°C, with particular reference to the utilization of a hot dry rock(HDR) geothermal resource. Thermodynamic performances of the TPORC system using eight different organic working fluids have also been investigated in terms of the net power outputs. Results show that a higher geofluid mass flow rate can make a considerable contribution to shortening the payback period(PBP) as well as to decreasing the levelized electricity cost(LEC), especially when the geofluid temperature is low. For the temperature range investigated, the order from high to low based on thermodynamic and techno-economic performances is found to be TPORC > DPORC > SPORC. In terms of using geothermal resources within the given temperatures range(100°C–200°C), the TPORC system can be a better choice for geothermal power generation so long as the wellhead geofluid temperature is between 140°C and 180°C.展开更多
With population growth around the world,municipal waste disposal and continued energy demand becomes some of the major challenges to deal with.In order to address these,an approach is required for an optimal waste man...With population growth around the world,municipal waste disposal and continued energy demand becomes some of the major challenges to deal with.In order to address these,an approach is required for an optimal waste management system that offers the population benefit with a lower environmental impact.This study evaluates the technical-economic and environmental impact analysis of a grid-connected waste to energy(WtE)plant to power a Univerisiti Teknologi Malaysia(UTM)community.The energy recovery potential of the waste stream was assessed using the life cycle assessment(LCA)method with GaBi^(TM) software(version 4).A technical,economic and environmental analysis was then carried out for the grid-connected WtE system using HOMERPro software with gasification conversion technology.The cash flow analysis was based on levelized costs of energy(LCOE)and total net present value(NPV).The results gave an NPV for the system at USD 1.11×10^(7),with most of the effects resulting from the grid operating costs and the LCOE of USD 0.43/kWh compared to the grid unit price of USD 0.7/kWh which corresponds to a saving of$0.27/kWh in energy purchase.From an environmental point of view,the results showed a significant reduction in carbon dioxide emissions from around 2,000 tons per year to around 400 tons per year.With regard to the amount of waste sent to landfills,the results show a significant improvement from 142,605.5 kg/year to 0.13 kg/year.展开更多
Standalone Solar PV systems have been vital in the improvement of access to energy in many countries.However,given the large cost of solar PV plants’components,in developing countries,there is a dear need for such co...Standalone Solar PV systems have been vital in the improvement of access to energy in many countries.However,given the large cost of solar PV plants’components,in developing countries,there is a dear need for such components to be subsidised and incentivised for the consumers to afford the produced energy.Moreover,there is a need for optimal sizing of the solar PV plants taking into account the solar information,energy requirement for various activities,and economic conditions in the off-grid regions in Rwanda.This study aims to develop optimally sized solar PV plants suited to rural communities in Rwanda.Likewise,it aims at characterizing the impacts of subsidies and incentives on the profitability and affordability of solar PV plants’energy in Rwanda.In the study,we have developed a model on basis of which the plant power(peak power)and costs of energy can be predicted given the load requirements using PVSyst.The model was validated using data corrected at eight different sites.Our generalized predictive model’s results matched the results obtained using field measurement data as inputs.The models have been able to replicate with a by degree of accuracy the peak powers and the plants’costs for different loads and were used to evaluate the economic viability of solar PV plants in Rwanda.It was found that with incentives and subsidies of 20%,the solar PV systems’costs,the Levelised Cost of Energy would drop from a maximum of 0.098 Euro to a minimum of 0.072 Euro,the payback period was reduced from a maximum of 7.5 years to a minimum of 6.0 years while the return on investments was seen to vary between 425.72 and 615.32 per cent over the plants’lifetime of 25 years.Overall our findings underscore the importance of government subsidies and incentives for solar PV energy generation projects to be significantly profitable.展开更多
Techno-economic analysis of a small-scale Modified Plant Oil (MPO) production plant that has an annual production capacity of 15,072,741 kg of MPO (batch process) was carried out to estimate the capital and operating ...Techno-economic analysis of a small-scale Modified Plant Oil (MPO) production plant that has an annual production capacity of 15,072,741 kg of MPO (batch process) was carried out to estimate the capital and operating costs of a plant. The analysis was done by using a computer model that was designed and simulated with an aid of SuperPro Designer (Version 4.32) software. The specified feedstock was crude Jatropha oil (JO) and the main product was MPO. The major processes involved were degumming, neutralisation and blending. Degumming involved the removal of gums or phospholipids, and two methods were used: water degumming and acid degumming, whereas blending involved mixing of degummed or purified JO with natural gas condensate (NGC) modifier to lower the viscosity of JO. From techno-economic analysis of the process, it was found that the total capital investment of a plant was about US $ 10,222,000 and the predicted unit production cost of MPO was US $ 1.315/kg at a value of US $ 1.0/kg of JO. The economic feasibility of MPO production was found to be highly influenced by the price of feedstock, which contributed about 95% of the total annual production cost. The relationship between plant throughput and unit cost of producing MPO showed that unit production cost was very sensitive to production rate at low annual throughputs. The MPO cost showed a direct linear relationship with the cost of JO, with a change of US $ 0.50/kg of MPO in MPO cost in every change of US $ 0.50/kg of JO in JO price. The process technology simulated was found to be economically viable and can be implemented in rural setting, taking into consideration Tanzania’s rural situation.展开更多
An eco-industrial park or estate is a community of manufactaring and service businesses located together on a common property. The goat of ElP is to create a win-win harmonious development aspect of ecooomic developme...An eco-industrial park or estate is a community of manufactaring and service businesses located together on a common property. The goat of ElP is to create a win-win harmonious development aspect of ecooomic development and environmental protection. This paper emphasizes that the external .effect of an EIP is its main characteristic of technoeconomic evaluation for eco-industrial park project. From the view of the property, rights, the EIP's product is typicalty public-private. The government should take some inca.rares for the quantitative analysis on ecological positive externalities of the enterprises in EIP, and also should adopt Coase's Theorem, which supports that the market transaction is the best way to deal with positive externalities (external economics or diseconoraics), or Pigou's Theorem, which holds that the government anti-positive externalities programs are the best way to cope with positive externalities, to internalize the EIP's external effects, which is also a fundamental tool to encourage investors to actively invest in EIP projects, Furthermore. this paper thinks that the EIP 's income should be equal to the income of staple products of the private property, and that of its by-products of the public property. According to this principle, this paper has put forward three major indicators, net present value (NPV), internal rate of renan (IRR), and investment repayment period (IRP), which are also extensively used indicators in ardinary project techno-economic evaluation model to evaluate EIP technoeconomic effects. Theoretically, the indicatory not only can be used in EIP project evaluation, but also can provide a quantitative measure toot for the government to support EIP's construction to the maximum. In the end. a case is analyzed.展开更多
The general theme-“ethics in the future”-intends to question a form of human knowledge,ethics,in relation to a dimension of time,the future.In broader terms,the title refers to a question about the relationship betw...The general theme-“ethics in the future”-intends to question a form of human knowledge,ethics,in relation to a dimension of time,the future.In broader terms,the title refers to a question about the relationship between knowledge and time,which in turn includes questions such as:“To what do different forms of knowledge-ethics,economics,physics-refer when they discuss the future?”;“What do they mean by a possible,probable,preferable future?”;“What future emerges through their key concepts?”;“What kind of future challenges present knowledge within an epochal context that is established in the form of an incessant reproduction of relative means and ends,one that is constantly outdated?”;“What form of knowledge is required first and foremost so that the establishment of this epoch can take place?”展开更多
Built on artificial intelligence, digitalization, and information technologies, the "Third Industrial Revolution "" transforms large-scale assembly lines and flexible manufacturing system with fundamental modern ma...Built on artificial intelligence, digitalization, and information technologies, the "Third Industrial Revolution "" transforms large-scale assembly lines and flexible manufacturing system with fundamental modern manufacturing technologies and features personalized manufacturing, which is enabled by reconfigurable manufacturing system, and quick market response. It is a profound transformation of techno-economic paradigms, imbedded in the technology, management, and institutional systems. As this revolution deepens, it is likely that manufacturing and the manufacturing sector would acquire new definitions. In addition, the resource foundation and factor structure, which are central to the competitiveness of a nation and an enterprise, would perhaps be reconfigured, hence rewriting the landscape of global industrial competition. Under this scenario, the "smiling curve '" which used to portray the economic features of the value chain, may change into a "silence curve" or even "sadness curve ". The catching- up pathway of latecomer countries, as predicted by the traditional 'flying geese model", is likely to be blocked, solidifying the division of"core and periphery countries" which is unfavorable to developing countries. Industrial competition between countries would move from competition between enterprises and supply chains to competition in industrial ecosystems, matdng system adaptability and dynamics the key to long-term industrial competitiveness. As an effort to embrace the "Third Industrial Revolution" and meet the challenges brought by "multi-facets competition" with developed industrial nations in various links of value chain, in the future China should make appropriate adjustments in its strategies for economic transition and upgrading, global competition, technological innovation, industrial development and information technology.展开更多
India generates more than 140 million tonnes of surplus crop residue every year In Haryana, the agricultural sector alone produces 24.64 million tonnes of residue annually;of which only 71</span><span style=&...India generates more than 140 million tonnes of surplus crop residue every year In Haryana, the agricultural sector alone produces 24.64 million tonnes of residue annually;of which only 71</span><span style="white-space:nowrap;font-family:Verdana;">%</span><span style="font-family:Verdana;"></span><span style="font-family:Verdana;"> is consumed in various domestic and commercial activities within the state. The rest of the material is burned causing severe contamination of air with smoke. There is an urgent need to identify suitable and sustainable conversion technologies that are efficient, eco-friendly as well as cost-effective for managing the huge available biomass not only in the state but also in the country. This paper reviews briefly the available crop residue and quantities burned, proposes a scheme to incorporate part of the residue in the field for its fertilizer value. The remaining biomass is harvested for animal feed and the excess is converted to bioenergy and biofuels. Among the developed and developing biofuels, the paper identifies biogas production from biomass for on-farm use. Pelletization is identified as an enabling technology to provide high quality feedstock for conversion to heat/power and in near future to advanced biofuels.展开更多
Grasslands in northern China serve the country as both an ecological barrier and a livestock production base.There,installing enclosures has been becoming the major grassland restoration measure adopted by many local ...Grasslands in northern China serve the country as both an ecological barrier and a livestock production base.There,installing enclosures has been becoming the major grassland restoration measure adopted by many local governments.However,the effects of restoration on both ecological and production benefits of grassland remain unclear for implemented grassland restoration policies.Therefore,a representative rangeland in northern China,the Maodeng pasture in Inner Mongolia Autonomous Region was selected as the study area,and remote sensing monitoring analyses were carried out to quantify the ecological benefits and economic benefits from 2015 to 2021.The results showed that:1) in terms of ecological benefits,the grassland area with a grassland coverage rate of more than 60% accounts for 32.3% of the regional area,and 86.4% of its grassland grew significantly better than the same period in2015,showing a significant improvement in grassland growth.Using the average amount of carbon per unit area as the ecological benefit evaluation index,it increased by 27.1% to 32.48Tg C/yr from 2015 to 2021.2) In terms of economic benefits,both theoretical grass production and livestock carrying capacity increased from 2015 to 2021.Compared to 2015,the theoretical grass production in 2021 increased by 24.8% to 71 900 t.The livestock carrying capacity reached 52 100 sheep units in 2021,nearly 11 000 sheep units more than that in 2015.During the study period,multiple economic indicators(on a per capita basis of permanent residents) for the pastoral area of Xilinhot City to which the Maodeng pasture belongs,have grown steadily.Per capita total income rose from 29 630 yuan(RMB) in2015 to 62 859 yuan(RMB) in 2021.Relying on grassland resources to develop the pastoral ecology also broadens the potential economic development space.Overall,the establishment of the reserve and the experiment of implanting an enclosure policy have had a significant and positive impact on Maodeng pasture’s development from both an ecological and economic perspective.With the support of scientific evidence,enclosure policy can be extended to more than 110 000 km~2 of grasslands in northern China with similar precipitation and temperature conditions,enhancing the productive and ecological potential of grasslands.The above research results will contribute to the scientific formulation of grassland pasture quality improvement plans in northern China.展开更多
Maltagliati et al.1 recently highlighted the vital role of affective experiences in promoting physical activity(PA).The authors suggested that positive affective experiences,rather than health benefits,can tip the bal...Maltagliati et al.1 recently highlighted the vital role of affective experiences in promoting physical activity(PA).The authors suggested that positive affective experiences,rather than health benefits,can tip the balance in favor of PA over sedentary alternatives.The authors proposed a new formal decision model between PA and sedentary alternatives and reported that when health benefits are the unique reason to action,the costs of PA(e.g.,effort)and the subjective value(SV)of sedentary alternatives(V_(sed))are the main drivers of decision-making processes.展开更多
文摘In recent years, there has been global interest in meeting targets relating to energy affordability and security while taking into account greenhouse gas emissions. This has heightened major interest in potential investigations into the use of supercritical carbon dioxide (sCO2) power cycles. Climate change mitigation is the ultimate driver for this increased interest;other relevant issues include the potential for high cycle efficiency and a circular economy. In this study, a 25 MWe recompression closed Brayton cycle (RCBC) has been assessed, and sCO2 has been proposed as the working fluid for the power plant. The methodology used in this research work comprises thermodynamic and techno-economic analysis for the prospective commercialization of this sCO2 power cycle. An evaluated estimation of capital expenditure, operational expenditure, and cost of electricity has been considered in this study. The ASPEN Plus simulation results have been compared with theoretical and mathematical calculations to assess the performance of the compressors, turbine, and heat exchangers. The results thus reveal that the cycle efficiency for this prospective sCO2 recompression closed Brayton cycle increases (39% - 53.6%) as the temperature progressively increases from 550˚C to 900˚C. Data from the Aspen simulation model was used to aid the cost function calculations to estimate the total capital investment cost of the plant. Also, the techno-economic results have shown less cost for purchasing equipment due to fewer components being required for the cycle configuration as compared to the conventional steam power plant.
文摘Transition toward a sustainable,low-carbon energy future requires innovative,integrated solutions.Hybrid solar-hydrogen systems(HSHSs),which combine solar energy harvesting and hydrogen production,have excellent prosepects to address challenges related to renewable energy generation,storage,and usage.This article presents an overview of the research on the technical and economic feasibility of HSHSs,aimed at comprehensively articulating their current state,notable advancements,and future research directions.It begins by elucidating solar energy principles and conversion methods and emphasizing the potential of solar energy for hydrogen production.This study then explores the definitions,components,and synergistic integration of HSHSs.Optimized energy conversion and storage methods for efficient hydrogen production and storage are also highlighted.This study reviews the techniques employed for techno-economic evaluations over the last six years,addressing challenges such as the intermittency of solar energy and the efficiency of hydrogen production technologies.This review of the ongoing research provides helpful insights into the technological and economic feasibility of HSHSs.This underscores the necessity of continuous research and development efforts to overcome existing challenges and unlock their full potential.These systems can play a vital role in achieving a cleaner and more resilient energy future by optimizing the system performance,reducing costs,and fostering supportive policy frameworks.
基金supported by National Natural Science Foundation of China(U1810205)The authors would also like to thank the Fund Program for the Scientific Activities of Selected Returned Overseas Professionals in Shanxi Province(20220003)Scientific and Technological Innovation Programs of Higher Education Institutions in Shanxi(2021L002)for their support.
文摘The natural gas(NG)reforming is currently one of the low-cost methods for hydrogen production.However,the mixture of H2 and CO_(2) in the produced gas inevitably includes CO_(2) and necessitates the costly CO_(2) separation.In this work,a novel double chemical looping involving both combustion(CLC)and sorption-enhanced reforming(SE-CLR)was proposed towards the co-production of H2 and CO(CLC-SECLRHC)in two separated streams.CLC provides reactant CO_(2) and energy to feed SECLRHC,which generates hydrogen in a higher purity,as well as the calcium cycle to generate CO in a higher purity.Techno-economic assessment of the proposed system was conducted to evaluate its efficiency and economic competitiveness.Studies revealed that the optimal molar ratios of oxygen carrier(OC)/NG and steam/NG for reforming were recommended to be 1.7 and 1.0,respectively.The heat integration within CLC and SECLRHC units can be achieved by circulating hot OCs.The desired temperatures of fuel reactor(FR)and reforming reactor(RR)should be 850C and 600C,respectively.The heat coupling between CLC and SECLRHC units can be realized via a jacket-type reactor,and the NG split ratio for reforming and combustion was 0.53:0.47.Under the optimal conditions,the H2 purity,the H2 yield and the CH4 conversion efficiency were 98.76%,2.31 mol mol-1 and 97.96%,respectively.The carbon and hydrogen utilization efficiency respectively were 58.60% and 72.45%in terms of the total hydrogen in both steam and NG.The exergy efficiency of the overall process reached 70.28%.In terms of the conventional plant capacity(75 × 103 t y^(-1))and current raw materials price(2500$t^(-1)),the payback period can be 6.2 years and the IRR would be 11.5,demonstrating an economically feasible and risk resistant capability.
文摘On the basis of practical projects in Chongqing,the thermal performance of heat exchangers (single U-tube type and double U-tube type) of the ground-source heat pump (GSHP) system in the hot summer was obtained and analyzed. The data obtained from test could match with the result deduced from theoretical calculation. From the test results,the cooling capacity of double U-tube is 1.6 times that of single U-tube. Taking cost per depth per watt Clq as the evaluation standard,Clq of single U-tube is 4.69 RMB$/W,and Clq of double U-tube is 3.14 RMB$/W. The double U-tube heat exchangers usage should be prioritized.
基金The research was supported by the National Natural Science Foundation of China(21978325 and 21776312)the Fundamental Research Funds for the Central Universities(20CX06073A,20CX06095A,and 20CX06096A).
文摘The integration of refinery and petrochemical units(IRPUs)has become an inevitable choice for the sustainable development of petrochemical industry.The utilization efficiency of petroleum resources could be improved obviously through IRPUs.However,integrating economic and environmental impacts into the model of IRPUs is still a grand challenge.Herein,a model called TEA-GHG-OPWM(Techno-Economic Analysis and GreenHouse Gases Oriented Plant-Wide Model)has been established on Aspen HYSYSTM platform to calculate the energy consumption,the technoeconomic performance,and the GHG emissions for two different kinds of schemes,viz,:VRHCU(Vacuum Residue Hydrocracking Unit)and VRDS-RFCC(Vacuum Residue Desulfurization and Residue Fluid Catalytic Cracking).Furthermore,a novel processing pathway named VGOHDT-HTMP-DC(Vacuum Gas Oil Hydrotreating,Hydrogenation and TMP coupling process and Delayed Coking)has also been developed to find methods to improve the economic performance based on a ten-million-CNY output value(TMYOV)and a reduced GHG emissions.Our results demonstrate that VRHCRU could consume more energy and emit more GHG(877.11 t of CO2 eq·TMYOV^-1·h^-1)than VRDS-RFCC(817.03 t of CO2 eq·TMYOV^-1·h^-1)and VGOHDT-HTMP-DC(721.96 t of CO2 eq·TMYOV^-1·h^-1),while obtaining a higher mass yield of petrochemicals.The VGOHDT-HTMP-DC process exhibits the lowest feedstock consumption,hydrogen consumption,energy consumption,and GHG emissions,indicating that VGOHDT-HTMP-DC has both well economic and environmentally friendly performance.
文摘Process algorithm, numerical model and techno-economic assessment of charge calculation and furnace bath optimization for target alloy for induction furnace-based steelmaking is presented in this study. The developed algorithm combines the make-to-order (MTO) and charge optimization planning (COP) of the steel melting shop in the production of target steel composition. Using a system-level approach, the unit operations involved in the melting process were analyzed with the purpose of initial charge calculation, prevailing alloy charge prediction and optimizing the sequence of melt chemistry modification. The model performance was established using real-time production data from a cast iron-based foundry with a 1- and 2-ton induction furnace capacity and a medium carbon-based foundry with a 10- and 15-ton induction furnace capacity. A simulation engine (CastMELT) was developed in Java IDE with a MySQL database for continuous interaction with changing process parameters to run the model for validation. The comparison between the model prediction and production results was analyzed for charge prediction, melt modification and ferroalloy optimization and possible cost savings. The model performance for elemental charge prediction and calculation purpose with respect to the charge input (at overall scrap meltdown) gave R-squared, Standard Error, Pearson correlation and Significance value of (0.934, 0.06, 0.97, 0.0003) for Carbon prediction, (0.962, 0.06, 0.98, 0.00009) for Silicon prediction, (0.999, 0.048, 0.999, 9E -11) for Manganese Prediction, and (0.997, 0.076, 0.999, 6E -7) for Chromium prediction respectively. Correlation analysis for melt modification (after charging of ferroalloy) using the model for after-alloying spark analysis compared with the target chemistry is at 99.82%. The results validate the suitability of the developed model as a functional system of induction furnace melting for combined charge calculation and melt optimization Techno-economic evaluation results showed that 0.98% - 0.25% ferroalloy saving per ton of melt is possible using the model. This brings about an annual production cost savings of 100,000 $/y in foundry A (medium carbon steel) and 20,000 $/y in foundry B (cast iron) on the use of different ferroalloy materials.
文摘With the rapid depletion of fossil fuel reserves, it is feared that the world will soon run out of its energy resources. This is a matter of concern for developing countries whose economy heavily leans on its use of energy. Under the circums-tances it is highly desirable that renewable energy resources should be utilized with maximum conversion efficiency to cope with the ever increasing energy demand. Furthermore, the global economic and political conditions that tend to make countries more dependent on their own energy resources have caused growing interest in the development and use of renewable energy based technologies. In terms of its environmental advantages, renewable energy sources generate electricity with insignificant contribution of carbon dioxide (CO2) or other greenhouse gases (GHG) to the atmosphere and they produce no pollutant discharge on water or soil and hence power generation from renewable becomes very important. Major types of renewable energy sources include solar, wind, hydro and biomass, all of which have huge potential to meet future energy challenges. Solar photovoltaic technology in one of the first among several renewable energy technologies that have been adopted worldwide for meeting the basic needs of electricity particularly in remote areas. In this paper literature review pertaining to techno-economic feasibility analysis of solar photovoltaic power generation is discussed. The literature is basically classified into the following three main category design methods, techno-economic feasibility of solar photovoltaic power generation, performance evaluations of various systems.
文摘Energy recovery from waste biomass can have significant impacts on the most pressing development challenges of rural poverty and environmental damages. In this paper, a techno-economic analysis is carried out for electricity generation by using timber and wood waste (T & WW) gasification in Iceland. Different expenses were considered, like capital, installation, engineering, operation and maintenance costs and the interest rate of the investment. Regarding to revenues, they come from of the electricity sale and the fee paid by the Icelandic municipalities for waste collection and disposal. The economic feasibility was conducted based on the economic indicators of net present value (NPV) and discounted payback period (DPP), bringing together three different subgroups based on gasifier capacities, subgroup a: 50 kW, subgroup b: 100 kW and subgroup c: 200 kW. The results show that total cost increases as the implemented power is increased. This indicator varies from 1228.6 k€ for subgroups a to 1334.7 k€ for subgroups b and 1479.5 k€ for subgroups c. It is worth mentioning that NPV is positive for three subgroups and it grows as gasifier scale is extended. NPV is about 122 k€ (111,020 $), 1824 k€ (1,659,840 $) and 4392 k€ (3,996,720 $) for subgroups a, b and c, respectively. Moreover, DPP has an inversely proportional to the installed capacity. It is around 5.5 years (subgroups a), 9.5 months (subgroups b) and 6 months (subgroups c). The obtained results confirm that using small scale waste biomass gasification integrated with power generation could be techno-economically feasible for remote area in Iceland.
基金We would like to thank individuals for their participation in our online survey as well as the study authors who responded to our data requests.This work was supported by the Economic and Social Research Council(ES/P000738/1)the Medical Research Council(MC_UU_00006/5)the University of Cambridge,and the National Health and Medical Research Council(GS2000053).The funders had no role in designing the study,analyzing the data,or writing the manuscript.
文摘Over time,physical activity(PA)has shifted from being a necessity to being an alternative.As a result,levels of PA have sharply decreased.1 Today,we are facing a worldwide pandemic of physical inactivity,with one death every 6 s attributed to insufficient PA.2 To counteract this trend,a tremendous effort is being made to promote regular PA across the lifespan,mainly through the dissemination of knowledge about the health benefits of accumulating sufficient PA.
文摘A shift to renewable energy sources will reduce emissions of greenhouse gases and secure future energy supplies. In this context, utilization of biogas will play a prominent role. Focus of this work is upgrading of biogas to fuel quality by membrane separation using a carbon hollow fibre(CHF) membrane and compare with a commercially available polymeric membrane(polyimide) through economical assessment. CHF membrane modules were prepared for pilot plant testing and performance measured using CO_2, O_2, N_2. The CHF membrane was modified through oxidation, chemical vapour deposition(CVD) and reduction process thus tailoring pores for separation and increased performance. The post oxidized and reduced carbon hollow fibres(PORCHFs) significantly exceeded CHF performance showing higher CO_2 permeance(0.021 m^3(STP)/m^2 h bar) and CO_2/CH_4 selectivity of 246(5 bar feed vs 50 mbar permeate pressure). The highest performance recorded through experiments(CHF and PORCHF) was used as simulation basis. A membrane simulation model was used and interfaced to 8.6 V Aspen HYSYS.A 300 Nm^3/h mixture of CO_2/CH_4 containing 30-50% CO_2 at feed pressures 6, 8 and 10 bar, was simulated and process designed to recover99.5% CH_4 with 97.5% purity. Net present value(NPV) was calculated for base case and optimal pressure(50 bar for CHF and PORCHF). The results indicated that recycle ratio(recycle/feed) ranged from 0.2 to 10, specific energy from 0.15 to 0.8(kW/Nm^3 feed) and specific membrane area from 45 to 4700(m^2/Nm^3 feed). The high recycle ratio can create problems during start-up, as it would take long to adjust volumetric flow ratio towards 10. The best membrane separation system employs a three-stage system with polyimide at 10 bar, and a two-stage membrane system with PORCHF membranes at 50 bar with recycle. Considering biomethane price of 0.78 $/Nm^3 and a lifetime of 15 years, the technoeconomic analysis showed that payback time for the best cascade is 1.6 months.
基金supported by the National Key Research and Development Program of the 13th FiveYear Plan of China(Grant No.2018YFB1501805)。
文摘Investigation of a triple-pressure organic Rankine cycle(TPORC) using geothermal energy for power generation with the net power output of the TPORC analyzed by varying the evaporation pressures, pinch temperature differences(tpp) and degrees of superheat(tsup) aimed to find the optimum operation conditions of the system. The thermodynamic performance of the TPORC was compared with a dual-pressure organic Rankine cycle(DPORC) and a single-pressure ORC(SPORC) for geofluid temperatures ranging from 100°C to 200°C, with particular reference to the utilization of a hot dry rock(HDR) geothermal resource. Thermodynamic performances of the TPORC system using eight different organic working fluids have also been investigated in terms of the net power outputs. Results show that a higher geofluid mass flow rate can make a considerable contribution to shortening the payback period(PBP) as well as to decreasing the levelized electricity cost(LEC), especially when the geofluid temperature is low. For the temperature range investigated, the order from high to low based on thermodynamic and techno-economic performances is found to be TPORC > DPORC > SPORC. In terms of using geothermal resources within the given temperatures range(100°C–200°C), the TPORC system can be a better choice for geothermal power generation so long as the wellhead geofluid temperature is between 140°C and 180°C.
基金supported/funded by the Ministry of Higher Education under Fundamental Research Grant.Grant No.FRGS/1/2018/TK07/UTM/02/6.https://www.mohe.gov.my/en/initiatives-2/187-program-utama/penyelidikan/548-research-grants-inf-ormation.
文摘With population growth around the world,municipal waste disposal and continued energy demand becomes some of the major challenges to deal with.In order to address these,an approach is required for an optimal waste management system that offers the population benefit with a lower environmental impact.This study evaluates the technical-economic and environmental impact analysis of a grid-connected waste to energy(WtE)plant to power a Univerisiti Teknologi Malaysia(UTM)community.The energy recovery potential of the waste stream was assessed using the life cycle assessment(LCA)method with GaBi^(TM) software(version 4).A technical,economic and environmental analysis was then carried out for the grid-connected WtE system using HOMERPro software with gasification conversion technology.The cash flow analysis was based on levelized costs of energy(LCOE)and total net present value(NPV).The results gave an NPV for the system at USD 1.11×10^(7),with most of the effects resulting from the grid operating costs and the LCOE of USD 0.43/kWh compared to the grid unit price of USD 0.7/kWh which corresponds to a saving of$0.27/kWh in energy purchase.From an environmental point of view,the results showed a significant reduction in carbon dioxide emissions from around 2,000 tons per year to around 400 tons per year.With regard to the amount of waste sent to landfills,the results show a significant improvement from 142,605.5 kg/year to 0.13 kg/year.
文摘Standalone Solar PV systems have been vital in the improvement of access to energy in many countries.However,given the large cost of solar PV plants’components,in developing countries,there is a dear need for such components to be subsidised and incentivised for the consumers to afford the produced energy.Moreover,there is a need for optimal sizing of the solar PV plants taking into account the solar information,energy requirement for various activities,and economic conditions in the off-grid regions in Rwanda.This study aims to develop optimally sized solar PV plants suited to rural communities in Rwanda.Likewise,it aims at characterizing the impacts of subsidies and incentives on the profitability and affordability of solar PV plants’energy in Rwanda.In the study,we have developed a model on basis of which the plant power(peak power)and costs of energy can be predicted given the load requirements using PVSyst.The model was validated using data corrected at eight different sites.Our generalized predictive model’s results matched the results obtained using field measurement data as inputs.The models have been able to replicate with a by degree of accuracy the peak powers and the plants’costs for different loads and were used to evaluate the economic viability of solar PV plants in Rwanda.It was found that with incentives and subsidies of 20%,the solar PV systems’costs,the Levelised Cost of Energy would drop from a maximum of 0.098 Euro to a minimum of 0.072 Euro,the payback period was reduced from a maximum of 7.5 years to a minimum of 6.0 years while the return on investments was seen to vary between 425.72 and 615.32 per cent over the plants’lifetime of 25 years.Overall our findings underscore the importance of government subsidies and incentives for solar PV energy generation projects to be significantly profitable.
文摘Techno-economic analysis of a small-scale Modified Plant Oil (MPO) production plant that has an annual production capacity of 15,072,741 kg of MPO (batch process) was carried out to estimate the capital and operating costs of a plant. The analysis was done by using a computer model that was designed and simulated with an aid of SuperPro Designer (Version 4.32) software. The specified feedstock was crude Jatropha oil (JO) and the main product was MPO. The major processes involved were degumming, neutralisation and blending. Degumming involved the removal of gums or phospholipids, and two methods were used: water degumming and acid degumming, whereas blending involved mixing of degummed or purified JO with natural gas condensate (NGC) modifier to lower the viscosity of JO. From techno-economic analysis of the process, it was found that the total capital investment of a plant was about US $ 10,222,000 and the predicted unit production cost of MPO was US $ 1.315/kg at a value of US $ 1.0/kg of JO. The economic feasibility of MPO production was found to be highly influenced by the price of feedstock, which contributed about 95% of the total annual production cost. The relationship between plant throughput and unit cost of producing MPO showed that unit production cost was very sensitive to production rate at low annual throughputs. The MPO cost showed a direct linear relationship with the cost of JO, with a change of US $ 0.50/kg of MPO in MPO cost in every change of US $ 0.50/kg of JO in JO price. The process technology simulated was found to be economically viable and can be implemented in rural setting, taking into consideration Tanzania’s rural situation.
文摘An eco-industrial park or estate is a community of manufactaring and service businesses located together on a common property. The goat of ElP is to create a win-win harmonious development aspect of ecooomic development and environmental protection. This paper emphasizes that the external .effect of an EIP is its main characteristic of technoeconomic evaluation for eco-industrial park project. From the view of the property, rights, the EIP's product is typicalty public-private. The government should take some inca.rares for the quantitative analysis on ecological positive externalities of the enterprises in EIP, and also should adopt Coase's Theorem, which supports that the market transaction is the best way to deal with positive externalities (external economics or diseconoraics), or Pigou's Theorem, which holds that the government anti-positive externalities programs are the best way to cope with positive externalities, to internalize the EIP's external effects, which is also a fundamental tool to encourage investors to actively invest in EIP projects, Furthermore. this paper thinks that the EIP 's income should be equal to the income of staple products of the private property, and that of its by-products of the public property. According to this principle, this paper has put forward three major indicators, net present value (NPV), internal rate of renan (IRR), and investment repayment period (IRP), which are also extensively used indicators in ardinary project techno-economic evaluation model to evaluate EIP technoeconomic effects. Theoretically, the indicatory not only can be used in EIP project evaluation, but also can provide a quantitative measure toot for the government to support EIP's construction to the maximum. In the end. a case is analyzed.
文摘The general theme-“ethics in the future”-intends to question a form of human knowledge,ethics,in relation to a dimension of time,the future.In broader terms,the title refers to a question about the relationship between knowledge and time,which in turn includes questions such as:“To what do different forms of knowledge-ethics,economics,physics-refer when they discuss the future?”;“What do they mean by a possible,probable,preferable future?”;“What future emerges through their key concepts?”;“What kind of future challenges present knowledge within an epochal context that is established in the form of an incessant reproduction of relative means and ends,one that is constantly outdated?”;“What form of knowledge is required first and foremost so that the establishment of this epoch can take place?”
文摘Built on artificial intelligence, digitalization, and information technologies, the "Third Industrial Revolution "" transforms large-scale assembly lines and flexible manufacturing system with fundamental modern manufacturing technologies and features personalized manufacturing, which is enabled by reconfigurable manufacturing system, and quick market response. It is a profound transformation of techno-economic paradigms, imbedded in the technology, management, and institutional systems. As this revolution deepens, it is likely that manufacturing and the manufacturing sector would acquire new definitions. In addition, the resource foundation and factor structure, which are central to the competitiveness of a nation and an enterprise, would perhaps be reconfigured, hence rewriting the landscape of global industrial competition. Under this scenario, the "smiling curve '" which used to portray the economic features of the value chain, may change into a "silence curve" or even "sadness curve ". The catching- up pathway of latecomer countries, as predicted by the traditional 'flying geese model", is likely to be blocked, solidifying the division of"core and periphery countries" which is unfavorable to developing countries. Industrial competition between countries would move from competition between enterprises and supply chains to competition in industrial ecosystems, matdng system adaptability and dynamics the key to long-term industrial competitiveness. As an effort to embrace the "Third Industrial Revolution" and meet the challenges brought by "multi-facets competition" with developed industrial nations in various links of value chain, in the future China should make appropriate adjustments in its strategies for economic transition and upgrading, global competition, technological innovation, industrial development and information technology.
文摘India generates more than 140 million tonnes of surplus crop residue every year In Haryana, the agricultural sector alone produces 24.64 million tonnes of residue annually;of which only 71</span><span style="white-space:nowrap;font-family:Verdana;">%</span><span style="font-family:Verdana;"></span><span style="font-family:Verdana;"> is consumed in various domestic and commercial activities within the state. The rest of the material is burned causing severe contamination of air with smoke. There is an urgent need to identify suitable and sustainable conversion technologies that are efficient, eco-friendly as well as cost-effective for managing the huge available biomass not only in the state but also in the country. This paper reviews briefly the available crop residue and quantities burned, proposes a scheme to incorporate part of the residue in the field for its fertilizer value. The remaining biomass is harvested for animal feed and the excess is converted to bioenergy and biofuels. Among the developed and developing biofuels, the paper identifies biogas production from biomass for on-farm use. Pelletization is identified as an enabling technology to provide high quality feedstock for conversion to heat/power and in near future to advanced biofuels.
基金Under the auspices of the Inner Mongolia Autonomous Region Science and Technology Achievement Transformation Special Project(No.2020CG0123)the Strategic Priority Research Program of Chinese Academy of Sciences(No.XDA26050301-01)。
文摘Grasslands in northern China serve the country as both an ecological barrier and a livestock production base.There,installing enclosures has been becoming the major grassland restoration measure adopted by many local governments.However,the effects of restoration on both ecological and production benefits of grassland remain unclear for implemented grassland restoration policies.Therefore,a representative rangeland in northern China,the Maodeng pasture in Inner Mongolia Autonomous Region was selected as the study area,and remote sensing monitoring analyses were carried out to quantify the ecological benefits and economic benefits from 2015 to 2021.The results showed that:1) in terms of ecological benefits,the grassland area with a grassland coverage rate of more than 60% accounts for 32.3% of the regional area,and 86.4% of its grassland grew significantly better than the same period in2015,showing a significant improvement in grassland growth.Using the average amount of carbon per unit area as the ecological benefit evaluation index,it increased by 27.1% to 32.48Tg C/yr from 2015 to 2021.2) In terms of economic benefits,both theoretical grass production and livestock carrying capacity increased from 2015 to 2021.Compared to 2015,the theoretical grass production in 2021 increased by 24.8% to 71 900 t.The livestock carrying capacity reached 52 100 sheep units in 2021,nearly 11 000 sheep units more than that in 2015.During the study period,multiple economic indicators(on a per capita basis of permanent residents) for the pastoral area of Xilinhot City to which the Maodeng pasture belongs,have grown steadily.Per capita total income rose from 29 630 yuan(RMB) in2015 to 62 859 yuan(RMB) in 2021.Relying on grassland resources to develop the pastoral ecology also broadens the potential economic development space.Overall,the establishment of the reserve and the experiment of implanting an enclosure policy have had a significant and positive impact on Maodeng pasture’s development from both an ecological and economic perspective.With the support of scientific evidence,enclosure policy can be extended to more than 110 000 km~2 of grasslands in northern China with similar precipitation and temperature conditions,enhancing the productive and ecological potential of grasslands.The above research results will contribute to the scientific formulation of grassland pasture quality improvement plans in northern China.
文摘Maltagliati et al.1 recently highlighted the vital role of affective experiences in promoting physical activity(PA).The authors suggested that positive affective experiences,rather than health benefits,can tip the balance in favor of PA over sedentary alternatives.The authors proposed a new formal decision model between PA and sedentary alternatives and reported that when health benefits are the unique reason to action,the costs of PA(e.g.,effort)and the subjective value(SV)of sedentary alternatives(V_(sed))are the main drivers of decision-making processes.