CO2 reforming of CH4 by binode thermal plasma

A binode thermal plasma is first applied to CO₂ reforming of CH₄ to investigate how to enlarge the process and lower energy consumption. Experimental study is conducted in two modes. One is to introduce feed gases (CH₄ and CO₂) only into discharge region between the first anode and the second anode as plasma-forming gas; the other is to introduce them not only into discharge region but also into the plasma jet from the exit of plasma generator. The experimental results show that, the former brings about higher conversion and selectivity but appreciably lower energy conversion efficiency due to its higher energy utilization, while the latter brings about higher energy conversion efficiency but somewhat lower conversion and selectivity due to its larger feeding of CH₄ and CO₂. Furthermore, during discharge in both modes, the oxidation on cathode and anode, or carbon deposition in plasma generator is not observed.     

CO2 reforming of CH4 by combination of thermal plasma and catalyst

Experiments on synthesis gas preparation from dry reforming of methane by carbon dioxide with thermal plasma only and cooperation of thermal plasma with commercial catalysts have been performed. In all experiments, nitrogen gas was used as the plasma gas to form a high-temperature jet injected into a tube reactor. A mixture of _CH4${\mathrm{CH}}_4$ and _CO2${\mathrm{CO}}_2$ was fed vertically into the jet. Both kinds of experiments were conducted in the same conditions, such as total flux of feed gases, the molar ratio of _CH4/_CO2${\mathrm{CH}}_4/{\mathrm{CO}}_2$, and the plasma power except with or without catalysts in the tube reactor. Higher conversion of _CH4${\mathrm{CH}}_4$ and _CO2${\mathrm{CO}}_2$, higher selectivity of _H2${\mathrm{H}}_2$ and CO, and higher specific energy of the process were achieved by thermal plasma with catalysts. For example, the conversions of _CH4${\mathrm{CH}}_4$ and _CO2${\mathrm{CO}}_2$ were high to 96.33% and 84.63%, and the selectivies of CO and _H2${\mathrm{H}}_2$ were also high to 91.99% and 74.23%, respectively. Both were 10–20%$10–20\%$ higher than those by thermal plasma only.     

CO2 reforming of CH4 by synergies of binode thermal plasma and catalysts

To reduce the energy consumption of the process of CO₂ reforming CH₄ by plasma, the experiments about synergies of thermal plasma and commercial Z107 Ni/Al₂O₃ catalysts are investigated in three elaborate modes: the binode plasma only, the combination of the plasma and catalysts (CPC), the CPC with part of feed gases introduced into plasma discharge region. The optimal specific energy of 193 kJ/mol and energy conversion efficiency of 66% are achieved under the conditions of CH₄/CO₂ of 4/6, input power at 14.4 kW, feed gases of 5 m³/h in mode 3, when the conversions of CH₄ and CO₂ are 77% and 62%, and the selectivities of H₂ and CO are 88% and 97%, respectively. The experimental results are very close to the industrial requirement compared with steam-reforming process. The excellent performance of this process is attributed to three different reaction mechanisms, which will be discussed in this paper.     

CO2 reforming of CH4 by atmospheric pressure glow discharge plasma: A high conversion ability

CO₂ reforming of CH₄ to syngas has been investigated by a special designed plasma reactor of atmospheric pressure glow discharge. High conversion of CH₄, CO₂, and high selectivity of CO, H₂, as well as high conversion ability are carried out. The experiment is operated in wider parameter region, such as CH₄/CO₂ from 3/7 to 6/4, input power from 49.50 W to 88.40 W and total feed flux from 360 mL/min to 4000 mL/min. The highest conversion of CH₄ and CO₂ is 98.52% and 90.30%, respectively. Under the experimental conditions of CH₄/CO₂ rate at 4/6, input power at 69.85 W and total feed flux at 2200 mL/min, the conversion ability achieves a maximum of 12.21 mmol/kJ with the conversion of CH₄ and CO₂ is 60.97% and 49.91%, the selectivity of H₂ and CO is 89.30% and 72.58%, H₂/CO rate is 1.5, respectively. This process has advantages of relatively large treatment and high conversion ability, which is a benefit from a special designed plasma reactor.     

CH4-CO2 reforming by plasma - challenges and opportunities

CH₄-CO₂ reforming is of rapid growing interest for reasons of the continuous decrease of petroleum resources and the emphasis on the environmental situation for greenhouse gas mitigation. Plasma technology is considered to be one of potential ways for CH₄-CO₂ reforming. This paper presents an overview of CH₄-CO₂ reforming by cold plasmas and thermal plasma. The evaluations for their performances and the key factors in different plasmas are given. In particular, the attention is focused on how to achieve higher conversions at high feed-gas flow rate, so as to lessen the energy consumption in the process by plasma to meet the requirements of industrial application. To obtain the aim, three key factors, electron density, plasma temperature and reactor configuration related to the process are emphasized. Considering the current status of CH₄-CO₂ reforming by plasma, there is an opportunity to improve the energy conversion efficiency and the treatment capacity of the process by optimizing both plasma form and reactor design in future work.     

CO2 emissions,energy usage,and output in Central America

This study extends the recent work of Ang (2007) [Ang, J.B., 2007. CO₂ emissions, energy consumption, and output in France. Energy Policy 35, 4772–4778] in examining the causal relationship between carbon dioxide emissions, energy consumption, and output within a panel vector error correction model for six Central American countries over the period 1971–2004. In long-run equilibrium energy consumption has a positive and statistically significant impact on emissions while real output exhibits the inverted U-shape pattern associated with the Environmental Kuznets Curve (EKC) hypothesis. The short-run dynamics indicate unidirectional causality from energy consumption and real output, respectively, to emissions along with bidirectional causality between energy consumption and real output. In the long-run there appears to be bidirectional causality between energy consumption and emissions.     

CO2 emissions,electricity consumption and output in ASEAN

This study examines the causal relationship between carbon dioxide emissions, electricity consumption and economic growth within a panel vector error correction model for five ASEAN countries over the period 1980–2006. The long-run estimates indicate that there is a statistically significant positive association between electricity consumption and emissions and a non-linear relationship between emissions and real output, consistent with the environmental Kuznets curve. The long-run estimates, however, do not indicate the direction of causality between the variables. The results from the Granger causality tests suggest that in the long-run there is unidirectional Granger causality running from electricity consumption and emissions to economic growth. The results also point to unidirectional Granger causality running from emissions to electricity consumption in the short-run.     

Economic growth, CO2 emissions, and fossil fuels consumption in Iran

Environmental issues have attracted renewed interest and more attention during recent years due to climatic problems associated with the increased levels of pollution and the deterioration of the environmental quality as a result of increased human activity. This paper investigates the causal relationships between economic growth, carbon emission, and fossil fuels consumption, using the relatively new time series technique known as the Toda-Yamamoto method for Iran during the period 1967–2007. Total fossil fuels, petroleum products, and natural gas consumption are used as three proxies for energy consumption. Empirical results suggest a unidirectional Granger causality running from GDP and two proxies of energy consumption (petroleum products and natural gas consumption) to carbon emissions, and no Granger causality running from total fossil fuels consumption to carbon emissions in the long run. The results also show that carbon emissions, petroleum products, and total fossil fuels consumption do not lead to economic growth, though gas consumption does.     

CO2 emissions,energy consumption and economic growth in China: A panel data analysis

This paper examines the causal relationships between carbon dioxide emissions, energy consumption and real economic output using panel cointegration and panel vector error correction modeling techniques based on the panel data for 28 provinces in China over the period 1995–2007. Our empirical results show that CO₂ emissions, energy consumption and economic growth have appeared to be cointegrated. Moreover, there exists bidirectional causality between CO₂ emissions and energy consumption, and also between energy consumption and economic growth. It has also been found that energy consumption and economic growth are the long-run causes for CO₂ emissions and CO₂ emissions and economic growth are the long-run causes for energy consumption. The results indicate that China's CO₂ emissions will not decrease in a long period of time and reducing CO₂ emissions may handicap China's economic growth to some degree. Some policy implications of the empirical results have finally been proposed.     

CO2 emissions structure of Indian economy

This paper analyses carbon dioxide (CO₂) emissions of the Indian economy by producing sectors and due to household final consumption. The analysis is based on an Input–Output (IO) table and Social Accounting Matrix (SAM) for the year 2003–04 that distinguishes 25 sectors and 10 household classes. Total emissions of the Indian economy in 2003–04 are estimated to be 1217 million tons (MT) of CO₂, of which 57% is due to the use of coal and lignite. The per capita emissions turn out to be about 1.14 tons. The highest direct emissions are due to electricity sector followed by manufacturing, steel and road transportation. Final demands for construction and manufacturing sectors account for the highest emissions considering both direct and indirect emissions as the outputs from almost all the energy-intensive sectors go into the production process of these two sectors. In terms of life style differences across income classes, the urban top 10% accounts for emissions of 3416 kg per year while rural bottom 10% class accounts for only 141 kg per year. The CO₂ emission embodied in the consumption basket of top 10% of the population in urban India is one-sixth of the per capita emission generated in the US.     

Influence of European passenger cars weight to exhaust CO2 emissions

The increase of atmospheric CO₂ concentration influences climate changes. The road transport sector is one of the main anthropogenic sources of CO₂ emissions in the European Union (EU). One of the main parameters influencing CO₂ emissions from passenger cars (PCs) is their weight, which increases during last years. For the same driving distance, heavier vehicles need more work than lighter ones, because they have to move an extra weight, and thus more fuel is consumed and thus increased CO₂ emissions. The weight control of new PCs could be an efficient way to control their CO₂ emissions. After an analysis of the EU new PCs market, their segment distribution and their weight, some estimations for 2020 are presented. Based on this analysis, 13 base scenarios using several ways for the control of the weight of future European new PCs are used to estimate their CO₂ emissions and the benefit of each scenario. The results show that a significant benefit on CO₂ emissions could be achieved if the weight of each PC does not exceed an upper limit, especially if this limit is quite low. The benefit obtained by limitations of weight is higher than the benefit obtained from the expected decreased future fuel consumption. Similar results are obtained when the weight of new PCs does not exceed an upper limit within each segment, or when the weight of each new PC decreases.     

CO2 emissions,energy consumption and economic growth in BRIC countries

This paper examines dynamic causal relationships between pollutant emissions, energy consumption and output for a panel of BRIC countries over the period 1971–2005, except for Russia (1990–2005). In long-run equilibrium energy consumption has a positive and statistically significant impact on emissions, while real output exhibits the inverted U-shape pattern associated with the Environmental Kuznets Curve (EKC) hypothesis with the threshold income of 5.393 (in logarithms). In the short term, changes in emissions are driven mostly by the error correction term and short term energy consumption shocks, as opposed to short term output shocks for each country. Short-term deviations from the long term equilibrium take from 0.770 years (Russia) to 5.848 years (Brazil) to correct. The panel causality results indicate there are energy consumption–emissions bidirectional strong causality and energy consumption–output bidirectional long-run causality, along with unidirectional both strong and short-run causalities from emissions and energy consumption, respectively, to output. Overall, in order to reduce emissions and not to adversely affect economic growth, increasing both energy supply investment and energy efficiency, and stepping up energy conservation policies to reduce unnecessary wastage of energy can be initiated for energy-dependent BRIC countries.     

Income and CO2 emissions: Evidence from panel unit root and cointegration tests

This paper re-investigates the stationarity properties of per capita carbon dioxide (CO₂) emissions and real Gross Domestic Product (GDP) per capita for 109 countries within seven regional panel sets covering 1971–2003. We apply the recent unit-root test of the panel seemingly unrelated regressions augmented Dickey–Fuller (SURADF) test developed by Breuer et al. [2001. Misleading inferences from panel unit-root tests with an illustration from purchasing power parity. Review of International Economics 9, 482–493; 2002. Series-specific unit-root tests with panel data, Oxford Bulletin of Economics and Statistics 64, 527–546]. The panel SURADF test accounts for the presence of cross-country correlations in the data, and the parameters in the panel specification vary across countries. More importantly, this test allows us to identify how many and which members of the panel contain a unit root. Overall, our empirical results illustrate that real GDP and CO₂ emissions in these countries are a mixture of I(0) and I(1) processes, and that the traditional panel unit-root tests could lead to misleading inferences as well as the conduct of cointegration analysis being perhaps inappropriate. The results of our analysis carry critical implications for the modeling of CO₂ emissions and GDP because of the different orders of integration for the two variables.     

The cost of pipelining climate change mitigation: An overview of the economics of CH4, CO2 and H2 transportation

Gases like CH₄, CO₂ and H₂ may play a key role in establishing a sustainable energy system: CH₄ is the least carbon-intensive fossil energy resource; CO₂ capture and storage can significantly reduce the climate footprint of especially fossil-based electricity generation; and the use of H₂ as energy carrier could enable carbon-free automotive transportation. Yet the construction of large pipeline infrastructures usually constitutes a major and time-consuming undertaking, because of safety and environmental issues, legal and (geo)political siting arguments, technically un-trivial installation processes, and/or high investment cost requirements. In this article we focus on the latter and present an overview of both the total costs and cost components of the distribution of these three gases via pipelines. Possible intricacies and external factors that strongly influence these costs, like the choice of location and terrain, are also included in our analysis. Our distribution cost breakdown estimates are based on transportation data for CH₄, which we adjust for CO₂ and H₂ in order to account for the specific additional characteristics of these two gases. The overall trend is that pipeline construction is no longer subject to significant cost reductions. For the purpose of designing energy and climate policy we therefore know in principle with reasonable certainty what the minimum distribution cost components of future energy systems are that rely on pipelining these gases. We describe the reasons why we observe limited learning-by-doing and explain why negligible construction cost reductions for future CH₄, CO₂ and H₂ pipeline projects can be expected. Cost data of individual pipeline projects may strongly deviate from the global average because of national or regional effects related to the type of terrain, but also to varying costs of labor and fluctuating market prices of components like steel.     

Natural emissions of CO2 from the geosphere and their bearing on the geological storage of carbon dioxide

Carbon dioxide (CO₂) capture and storage has the potential to reduce CO₂ emissions from fossil fuel combustion. Although leakage from monitored CO₂ injection sites has been minimal to non-existent, experience from the natural gas storage industry suggests that, if it becomes a widely deployed technology, leaks may be expected from some storage sites. Natural occurrences of CO₂ in the geosphere, some of which have been exploited, provide insights into the types of emissions that might be expected from anthropogenic CO₂ storage sites. CO₂ emission sites are commonly found in clusters in CO₂-prone geological provinces: the most common natural emissions sites in sedimentary basins consist of carbonated springs and mofettes. These represent at worst only a local hazard. In volcanic and hydrothermal provinces, more energetic emissions may occur due to active supply from degassing magma. These include rare, sudden emissions from fissures and craters that have caused fatalities. It is unlikely that such provinces would be considered for CO₂ storage Major lake overturn events such as occurred at Lake Nyos in 1986 are considered highly unlikely to occur as a result of CO₂ storage, not least because CO₂ levels in lake waters can be monitored and remediated. Natural CO₂ fields indicate that under favourable conditions CO₂ can be retained in the subsurface for millions of years. The main risk from man-made CO₂ storage sites that does not have any close analogy in nature is considered to be a well blowout. A blowout that took place at a natural CO₂ field provides some indication of the likely hazard.     

Assessment of CO2 emissions reduction in a distribution warehouse

Building energy use accounts for almost 50% of the total CO₂ emissions in the UK. Most of the research has focused on reducing the operational impact of buildings, however in recent years many studies have indicated the significance of embodied energy in different building types. This paper primarily focuses on illustrating the relative importance of operational and embodied energy in a flexible use light distribution warehouse. The building is chosen for the study as it is relatively easy to model and represents many distribution centres and industrial warehouses in Europe.A carbon footprinting study was carried out by conducting an inventory of the major installed materials with potentially significant carbon impact and material substitutions covering the building structure. Ecotect computer simulation program was used to determine the energy consumption for the 25 years design life of the building. This paper evaluates alternative design strategies for the envelope of the building and their effects on the whole life emissions by investigating both embodied and operational implications of changing the envelope characteristics. The results provide an insight to quantify the total amount of CO₂ emissions saved through design optimisation by modeling embodied and operational energy.     

The Ni/ZrO2 catalyst and the methanation of CO and CO2

The Ni/ZrO₂ catalyst is one of the most active systems for the methanation of CO to be employed in the hydrogen purification for PEMFC. This contribution aims to study the effect of ZrO₂ on the methanation of CO and CO₂. The catalytic behavior of Ni/ZrO₂, Ni/SiO₂, a physical mixture comprising Ni and ZrO_2, and a double-bed reactor were evaluated. The TPD of CO and CO₂, TPSR and the cyclohexane dehydrogenation reaction were carried out to describe the catalysts and the reactions. The high activity of Ni/ZrO₂ catalyst toward the methanation of CO is related to the presence of active sites on the ZrO₂ surface. The methanation of CO occurs on ZrO₂ due to its ability to adsorb CO and also because of the hydrogen spillover phenomenon. Apparently, the effect of ZrO₂ is less relevant for the methanation of CO₂. Ni/ZrO₂ is a very promising system for the purification of hydrogen.     

Hydrogen impacts on performance and CO2 emissions from a diesel power generator

This work investigates the performance and carbon dioxide (CO₂) emissions from a stationary diesel engine fueled with diesel oil (B5) and hydrogen (H₂). The performance parameters investigated were specific fuel consumption, effective engine efficiency and volumetric efficiency. The engine was operated varying the nominal load from 0 kW to 40 kW, with diesel oil being directly injected in the combustion chamber. Hydrogen was injected in the intake manifold, substituting diesel oil in concentrations of 5%, 10%, 15% and 20% on energy basis, keeping the original settings of diesel oil injection. The results show that partial substitution of diesel oil by hydrogen at the test conditions does not affect significantly specific fuel consumption and effective engine efficiency, and decreases the volumetric efficiency by up to 6%. On the other hand the use of hydrogen reduced CO₂ emissions by up to 12%, indicating that it can be applied to engines to reduce global warming effects.     

Environmental and economic benefits resulting from citizens’ participation in CO2 emissions trading: An efficient alternative solution to the voluntary compensation of CO2 emissions

Over the last few months in the emerging and lucrative carbon project market, a growing number of organizations have proposed to offset citizens’ greenhouse gas emissions. The target of these carbon-offset initiatives is to satisfy the increasing demand of individuals wishing to take part in the fight against climate change. In this paper, we review and criticize these carbon-offsetting programs in general terms. We then propose an alternative that, in our opinion, should prove to be a better solution for citizens who are willing to pay for protecting the environment. This alternative is to organize citizens’ participation in carbon emissions trading on a large scale in order to purchase and retire (destroy) CO₂ permits. To do so, a benevolent Regulator or non-governmental organization must correct certain CO₂ emissions market failures; this particularly concerns the high transaction costs, which represent an entry barrier and prevent citizens from purchasing and withholding permits. Based on theoretical findings, we demonstrate that implementing citizens’ participation in emissions trading is an economically efficient and a morally preferable option.     

The effect of carbon tax on per capita CO2 emissions

As the most efficient market-based mitigation instrument, carbon tax is highly recommended by economists and international organizations. Countries like Denmark, Finland, Sweden, Netherlands and Norway were the first adopters of carbon tax and as such, research on the impacts and problems of carbon tax implementation in these countries will provide great practical significance as well as caution for countries that are to levy the tax. Different from the existing studies that adopt the model simulation approaches, in this article, we comprehensively estimate the real mitigation effects of the five north European countries by employing the method of difference-in-difference (DID). The results indicate that carbon tax in Finland imposes a significant and negative impact on the growth of its per capita CO₂ emissions. Meanwhile, the effects of carbon tax in Denmark, Sweden and Netherlands are negative but not significant. The mitigation effects of carbon tax are weakened due to the tax exemption policies on certain energy intensive industries in these countries. Notwithstanding, in Norway, as the rapid growth of energy products drives a substantial increase of CO₂ emissions in oil drilling and natural gas exploitation sectors, carbon tax actually has not realized its mitigation effects.