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Abstract Rapid economic growth and accelerating urbanization in the past three decades have accelerated the exhaustion of China’s mineral resources. China is the world’s largest consumer and importer of nickel resources; therefore, a growing domestic demand will increase China’s import dependence and in turn make it potentially vulnerable to supply shortages. One hundred years from 1950 to 2050 were examined for China’s nickel utilization. Identified domestic nickel resources can only sustain China’s industries until 2017, but nickel will reach peak utilization around the year of 2020–2022. Given the 5% annual increase in applications and the growing importation of minerals in China, the carrying duration of nickel resources until 2020 will require a nickel-recycling rate of more than 90%. To sustain China’s nickel utilization, future strategies should foster three solutions: maintaining a high level of imports, adjusting the landscape of nickel applications, and shifting from virgin mining of geological minerals to urban mining of anthropogenic resources.

In China, the national target for energy intensity reduction, when integrated with target disaggregation and information feedback systems, constitutes a numerical management system, which is a hallmark of modern governance. This paper points out the technical weaknesses of China's current numerical management system. In the process of target disaggregation, the national target cannot be fully disaggregated to local governments, sectors and enterprises without omissions. At the same time, governments at lower levels face pressure for reducing energy intensity that exceeds their respective jurisdictions. In the process of information feedback, information failure is inevitable due to statistical inaccuracy. Furthermore, the monitoring system is unable to correct all errors, and data verification plays a limited role in the examination system. To address these problems, we recommend that the government: use total energy consumption as the primary indicator of energy management; reform the accounting and reporting of energy statistics toward greater consistency, timeliness and transparency; clearly define the responsibility of the higher levels of government.

Using lignocellulosic biomass wastes to produce Hydrogen for the sustainable Hydrogen Economy can help reduce or eliminate the current heavy dependence on fossil energy. We hereby report a new pathway for H2 synthesis by simply applying commercial SrTiO3 catalyst in photoreforming processes following thermo-alkaline hydrolysis (TAH) pretreatment. Thanks to the thorough decomposition of the lignocellulosic matter under an optimized TAH condition, the obtained hydrolysate shows superior ability to produce H2. Its H2 production capacity is much better than that of TEOA and TEA, for which the cellulose hydrolysate was twice that of TEOA and 12 times that of TEA. This remarkable improvement is attributed to the selective formation of an important intermediate product, tartaric acid, which is for the first time identified as the key to enhancement of H2 generation from catalytic photoreforming processes. © 2022

Since CO2 capture and storage (CCS) is a viable CO2 abatement option, CO2 capture power plants (CCPPs) could become a significant part of the future generation mix. This paper investigates the flexibility of the operation of a representative post-combustion CCPP with ancillary facilities. A mathematical model of the operation of such a plant is developed. This model quantifies the relation between the major operating characteristics of a CCPP, including efficiency penalty, capacity penalty, net power output, and net CO2 emission. On this basis, a profit maximization model is proposed. This model would help a CCPP decide its power output schedule, CO2 capture schedule, and bidding strategies in response of volatile power and carbon prices in a day-ahead energy market and a cap-and-trade carbon emission market. The validity and the usefulness of the proposed model are demonstrated using numerical results.

This study innovatively combines mechanochemistry and high-temperature thermal reduction to achieve the recovery of valuable metals from spent LIBs. First, under the action of mechanical force, the crystal structure of lithium cobalt oxide (LiCoO2) found in the cathode materials of spent LIBs was destroyed and converted into lithium carbonate (Li2CO3) and Li-free residue (C/Co3O4) using dry ice as a co-grinding reagent. The optimum Li2CO3 recovery conditions were determined to be as follows: a ratio of dry ice: LiCoO2 powder mass of 20:1; a rotation speed of 700 rpm, and a reaction time of 1.5 h. With these conditions the maximum percentage of Li2CO3 recovered was 95.04 wt%. The Co3O4 in Li-free residue was reduced to a high-value Co0 product via a high-temperature (800 °C) heat treatment. Gibbs free energy analysis confirmed that the carbon in the Li-free residue could be used as a self-reducing reagent for the thermal reduction of Co3O4. The reactants and products of each step were characterized by XRD, FT-IR, XPS and SEM techniques. The green route for recycling spent LIBs that this study proposes realizes the green and cost-effective conversion of LiCoO2 to high-value products, which may become an outstanding example of recycling spent LIBs.

Abstract Transesterification of oil feedstocks using immobilized lipase (IL) is a promising process for biodiesel production. However, the running cost of this process is still higher than that of conversional chemical-catalyzed approaches. To address this challenge, both upstream and downstream processes have to be optimized. This review provides an overview of recent progresses in improving IL-catalyzed biodiesel production, focusing on mid- and down-stream processing such as immobilization of lipase, bioreactors development, process optimization, simulation and techno-economic evaluation. The immobilization of lipase is a costly process. Most of the commercial ILs are prepared by adsorption of free lipase on polymeric materials. However, to further reduce cost, works should be focused on developing cheap carriers and strengthening the interaction between enzyme and carrier but without significant loss of lipase activity. Running cost of lipase also can be reduced by improving its lifetime during transesterification. To achieve this goal, solvents can be used to prevent lipase leaching and eliminate the inhibitive effects of alcohol (usually methanol) and glycerol. Downstream processing includes important units to purify biodiesel products. In this part, works should be focused on minimizing energy consumption and waste effluents. A global process integration and optimization with economic evaluation also should be figured out to improve the economic feasibility of Il-catalyzed production of biodiesel.

As climate change, compound hot extremes (CHEs), daytime and nighttime persistent hot extremes, are projected to become much more frequent and intense, which may pose a serious threat to human health. However, evidence on the impact of CHEs on injury is rare.We collected injury death data and daily meteorological data from six Chinese provinces during 2013-2018. A time-stratified case-crossover design with two-stage analytic approach was applied to assess the associations of CHEs with injury mortality by intention, mechanism, age and gender. Using the projected daily temperatures of five General Circulation Models (GCMs), we projected the frequency of CHEs and CHEs-attributable mortality burden of injury under three Representative Concentration Pathway (RCP) scenarios.CHEs were significantly associated with increased injury mortality risk (RR = 1.14, 95%CI: 1.09-1.19), with strong effects on unintentional injuries (RR = 1.16, 95%CI:1.11,1.22) and intentional injuries (RR = 1.11, 95%CI:0.99,1.25). Female (RR = 1.21,95%CI: 1.13-1.29) and the elderly (RR = 1.30, 95%CI: 1.22-1.39) were more susceptible to CHEs. Both the frequency and injury mortality burden of CHEs showed a steep rising trend under RCP8.5 scenario, with a 7.37-fold and 8.22-fold increase respectively, by the end of the century, especially in southern, eastern, central and northwestern China.CHEs were associated with increased injury mortality risk, and the CHEs-attributable injury mortality burden was projected to aggravate substantially in the future as global warming. It is urgent to develop targeted adaptation policies to alleviate the health burden of CHEs.

With the recent rapid development of smart grid technology, the distribution grids become more active, and the interaction between transmission and distribution grids becomes more significant. However, in traditional power flow calculations, transmission and distribution grids are separated, which is not suitable for such future smart grids. To achieve a global unified power flow solution to support an integrated analysis for both transmission and distribution grids, we propose a global power flow (GPF) method that considers transmission and distribution grids as a whole in this paper. We construct GPF equations, and develop a master-slave-splitting (MSS) iterative method with convergence guarantee to alleviate boundary mismatches between the transmission and distribution grids. In our method, the GPF problem is split into a transmission power flow and a number of distribution power flow sub-problems, which supports on-line geographically distributed computation. Each sub-problem can be solved using a different power flow algorithm to capture the different features of transmission and distribution grids. An equivalent method is proposed to improve the convergence of the MSS-based GPF calculation for distribution grids that include loops. Numerical simulations validate the effectiveness of the proposed method, in particular when the distribution grid has loops or distributed generators.

Abstract In this study, the potential advantages of fuels derived from coffee waste were evaluated and quantified over the entire life cycle. Life cycle evaluation is important for achieving robust understanding because it covers the entire sequence of stages of fuel production and utilization. Coffee waste collection and transport, oil extraction, and biodiesel production and transport are the stages covered under the first life phase, called “well-to-pump.” Extensive engine tests were also conducted to assess the second life phase, “pump-to-wheel.” Environmental, economic, energetic, and technical criteria were encapsulated within the frame of each phase, and various evaluation tools that fit each life stage were adopted. The results showed that coffee biodiesel contributes to an 80.5% reduction in CO2 emissions compared with the hydrocarbon diesel during its life cycle. Moreover, the conversion efficiency of the raw material energy to fuel energy in the case of coffee biodiesel was 10% higher than that of the petro-diesel. An energy amount of 3.45 MJ is associated with coffee biodiesel for each 1 MJ consumed in its life cycle. The economic viability of coffee biodiesel was found to be very sensitive to the price of the coffee solid fuel (biomass pellets). The entire project is feasible only when the price of pellets is 40% of that of wood pellets or higher. Substantial reduction of tailpipe emissions was attained for CO, CO2, and HC, with 45.3%, 5.7%, and 23.6% reductions, respectively, for B20. Reductions of 10.3% and 7.5% were observed in the brake thermal efficiency and brake power, respectively. Thus, coffee biodiesel has significant advantages and potential, and its technological development merits further research.