微藻生物能源研究现状及展望

能源是现代社会发展的命脉,目前仍以化石燃料为主,而对化石燃料过度依赖导致的能源危机和环境问题日益突出,人类需要寻找可再生的清洁能源作为替代能源。微藻作为可持续的生物能源原料,具有巨大的发展潜力。本文综述了微藻原料获取各环节的研究现状,包括微藻育种、规模培养和采收,并重点论述了微藻生物质转化为生物能源产品的研究进展,包括生物柴油、生物乙醇、生物燃气、生物油,同时指出了微藻生物能源未来的研究方向。     

Energy use,industrial soot and vehicle exhaust pollution—China's regional air pollution recognition,performance decomposition and governance

The identification of “industrial soot” or “vehicle exhaust” pollution facilitates developing proper measures for the mitigation of regional air pollution. In order to identify the pollution types at a regional level, this paper applies the Luenberger productivity indicator to decompose air pollutant emissions performance. Furthermore, we simultaneously consider pollution rates and the productivity change. Thus, we propose a new modeling framework allowing for the variable-specific decomposition of the environmental performance along time and quantity dimensions to identify the underlying patterns. The panel data for 30 provinces and autonomous regions are then applied to identify regional atmospheric pollution type. The results show that SO₂ emission from industrial soot and NO_x emissions from vehicle exhaust constitute an important source of regional atmospheric environmental inefficiency, though the former seems to be more decisive. The southeast coastal provinces showed generally lower levels of inefficiency, compared to the northwest inland area. During the period of the 11th Five-Year Plan of China, industrial SO₂ emission performance contributed to the increase in the atmospheric environmental productivity, while traffic NO_x emissions acted as a negative factor in this regard. Therefore, the government should seek to increase the intensity of environmental regulation in transportation sector. At the country level, technical progress associated with both types of pollutions was positive and thus exceed the negative efficiency change for the same variables. In particular, in Beijing-Tianjin-Hebei region, the productivity changes in industrial SO₂ emissions and traffic NO_x emissions indicate a “stably advancing” type. The results further indicate that there are 18 provinces of China which have experienced mixed-type pollution. Jilin and Hainan were classified as provinces experiencing vehicle exhaust gas pollution, whereas Guizhou was defined as that subject to industrial soot pollution. The government should formulate and implement diversified support and regulation policies to govern SO₂ and NO_x pollution at the regional level.     

CO2 emissions and economic activity: A short-to-medium run perspective

This paper looks at the short-to-medium run impact of economic activity on CO₂ emissions in the United States, shifting the existing focus away from the long-run Environmental Kuznets Curve (EKC). Our novel methodological approach combines discrete wavelet transforms with dynamic factor models. This allows us to (i) estimate economic and emissions cycles at different frequencies, and (ii) let economic activity be estimated from many different economic variables, rather than focussing on a small number as in existing studies. From our results, one might at first conclude that emissions are not linked to economic activity in the short-run. However, when looking at the cycles uncovered at timescales of length one to three years, we see that there are indeed strong linkages. Policymakers therefore cannot be exclusively long-termist when evaluating the impact of economic policy on the environment.     

反应精馏过程中的多稳态分析

Reactive distillation processes for synthesis of ethylene glycol （EG） and ethyl tert-butyl ether （ETBE） were modeled with the simulation package ASPEN PLUS. The input multiplicity and output multiplicity were discussed with the method of sensitivity analysis for both cases. In EG production process, steady state multiplicities were studied in terms of effective liquid holdup volume and boil-up ratio. In ETBE synthesis process, the user kinetic subroutine was supplied into ASPEN PLUS firstly, and then the composition, temperature and reaction-rate profiles within the reactive distillation column were presented in detail. A set of stable solution branches based on distinct initial guesses for a range of boil-up ratio were found in EG synthesis. Input multiplicities were observed for a range of reboiler duty at several values of reflux ratio for ETBE synthesis process. These results can be used to avoid excessive energy consumption and achieve optimum design of reactive distillation column.     

Bimetallic Cu–Ni catalysts for the WGS reaction – Cooperative or uncooperative effect?

In this work, bimetallic Cu–Ni catalysts have been studied in the water-gas shift (WGS) reaction, and they have shown different levels of synergy and anti-synergy in terms of catalytic activity and selectivity to the desired products. Cu–Ni interactions alter the physicochemical properties of the prepared materials (i.e. surface chemistry, redox behaviour, etc.) and as a result, the catalytic trends are influenced by the catalysts' composition. Our study reveals that Cu enhances Ni selectivity to CO₂ and H₂ by preventing CO/CO₂ methanation, while Ni does not help to improve Cu catalytic performance by any means. Indeed, the monometallic Cu formulation has shown the best results in this study, yielding high levels of reactants conversion and excellent long-term stability. Interestingly, for medium-high temperatures, the bimetallic 1Cu–1Ni outperforms the stability levels reached with the monometallic formulation and becomes an interesting choice even when start-up/shutdowns operations are considered during the catalytic experiments.     

Environmental risk assessment of industrial facilities: Techniques,regulatory initiatives and insurance

Most companies that manufacture, handle or dispose of chemicals or petroleum products have the potential to cause environmental impairment, especially by longterm or gradual release of materials into the environment. This impairment creates potential liabilities that result from numerous regulations as well as from common law. One way to identify these potential environmental liabilities and exposures is through environmental risk assessment. The primary focus of an environmental risk assessment is to evaluate the potential for off-site gradual impairment arising from a company's operations. Such an assessment reviews the status of the firm's environmental risk exposure and is a useful internal tool for corporate planning. There are three major objectives in performing an environmental risk assessment: risk identification, risk evaluation and risk reduction. To identify risk, numerous criteria are used to determine the individual factors contributing to the potential for off-site exposure. The interaction of these individual risk factors is then used to evaluate the overall potential for gradual environmental impairment. After the risks have been evaluated, recommendations are made to reduce the potential exposures. In addition, implementation of risk reduction strategies accomplish the objective of legislative initiatives for protecting human health and the environment. Environmental risk management can and should be encouraged through legislative initiatives.     

Can China achieve its 2030 energy development targets by fulfilling carbon intensity reduction commitments?

China has proposed carbon intensity targets and energy development targets for 2030. This study investigates the linkages between these targets and assesses if China can achieve its energy development targets by fulfilling its carbon reduction commitments. To this end, it quantitatively evaluates the impact of carbon emission controls on the Chinese economy using a dynamic computable general equilibrium model. The results show that China's carbon abatement pledge cannot guarantee achievement of all energy objectives. China is likely to reach the upper limit of its carbon intensity target in 2020 and the lower limit in 2030 if current abatement efforts are maintained. To achieve the upper limit in 2030, the carbon price will be CNY 83/tCO₂. The energy consumption target for 2020 is likely to be realized but the 2030 target is not. A more stringent price constraint on carbon emissions would be helpful to the achievement of the non-fossil energy target in 2030, but would have a limited promoting effect on natural gas development. Our results reveal the linkages between China's energy targets and carbon emission targets, which is valuable to the cost-effective dual control of energy consumption and carbon emission.     

差示扫描量热法和质量平衡法测定林丹的纯度

目的通过差示扫描量热法(differential scanning calorimetry,DSC)和质量平衡法(mass balance,MB)2种不同方法对林丹(γ-丙体六六六)纯度标准物质进行纯度分析的研究。方法基于Van’t Hoff原理,即物质的熔融曲线来算出杂质含量,利用DSC法对林丹进行纯度分析;采用气相色谱面积归一化法测量林丹的主成分纯度值,顶空-气相色谱法测量溶剂残留,卡尔费休测定水分和灼烧法测定灼烧残渣来最终确定林丹纯度。结果 DSC法测定林丹纯度为99.92%,不确定度为0.05%,质量平衡法测得林丹纯度为99.74%,不确定度为0.02%。结论 2种不同原理的方法对林丹纯度的测量有较好的一致性。DSC法方法简单,可操作性强,所需样品量较小,对仪器精度要求较高,相对不确定度较大。质量平衡法适用于所有有机纯物质的纯度分析,考察因素较多,分析较全面,且不确定度相对较小,方法准确度高。