The potential of WHR/batch and cullet preheating for energy efficiency in the EU ETS glass industry and the related energy incentives

The European Emissions Trading Scheme (EU ETS) covers approximately 45% of European greenhouse gases (GHGs), 11,000 stationary installations as well as aircraft operators. The EU ETS particularly affects the energy-intensive industries while it imposes a significant risk of “carbon leakage,” i.e., the risk of EU industry departing to countries with weaker restraints on GHG emissions. The EU glass industry, being capital intensive and also requiring long investment cycles, is the world’s largest glass producer with a market share close to one third of global production. Therefore, it is of significant importance to view the position of the EU ETS glass industry in terms of energy conservation possibilities. The present paper utilizes a vertical approach to provide information on both ETS market evolution and specific technical information to support technological innovation to the glass industry. EU ETS glass industry is analyzed regarding the balance between allocated European Union emission allowances (EUAs), verified CO₂ emissions, and potential shortfall in allowances so as to determine the situation of glass industries and the extent of urge for energy-saving activities towards the strengthening of their position within the requirements of the EU ETS phase III. The replication potential of waste heat recovery (WHR) through batch preheating is specifically addressed since it is considered a promising technology according to the latest Best Available Techniques (BAT) reference document for the glass industry under Directive IED 2010/75/EU. A case study for a container glass furnace based on simulation results is presented investigating the impact of different operating and design configurations on specific energy consumption and CO₂ emissions.     

Degradation of proton exchange membrane fuel cells due to CO and CO2 poisoning

The CO and CO₂ poisoning effects on the degradation of cell performance of proton exchange membrane fuel cell (PEMFC) under transient stage were investigated. The mechanism of CO poisoning lies in the preferential adsorbing of CO to the platinum surface and the blocking of active sites of hydrogen. These phenomena were described with adsorption, desorption, and electro-oxidation processes of CO and hydrogen in the present work. In addition, it is well known that the reverse water gas shift reaction (RWGS) is the main effect of the CO₂ poisoning, through which a large part of the catalytic surface area becomes inactive due to the hydrogen dissociation. The predicted results showed that, by contaminating the fuel with 10 ppm CO at the condition of P_H = 0.8 atm and PCO₂=0.2 atm$P_{\text{C}{\text{O}}_2}=0.2\text{atm}$, the current density of the PEM fuel cell was lowered 28% with rate constant of RWGS k_rs from zero to 0.02. With 50 ppm CO, the performance drop was only 18%. For the reformed gas, CO₂ poisoning became much more significantly when the CO content in the reactant gas was small.     

Experimental study on a spark ignition engine fuelled by methane–hydrogen mixtures

In this study, effects on a spark ignition engine of mixtures of hydrogen and methane have been experimentally considered. This article presents the results of a four-cylinder engine test with mixtures of hydrogen in methane of 0, 10, 20 and 30% by volume. Experiments have been made varying the equivalence ratio. Equivalence ratios have been selected from 0.6 to 1.2. Each fuel has been investigated at 2000 rpm and constant load conditions. The result shows that NO emissions increase, HC, CO and _CO2${\mathrm{CO}}_2$ emission values decrease and brake thermal efficiency (BTE) values increase with increasing hydrogen percentage.     

On the way to 130 g CO2/km—Estimating the future characteristics of the average European passenger car

A new average CO₂ emissions limit for passenger cars was introduced in EU in 2009 imposing gradual average CO₂ emissions reduction to 130 g/km until 2015. This paper attempts to study possible changes in vehicle characteristics for meeting this limit taking into account the average European passenger car of 2007–2008. For this purpose first the most important factors affecting vehicle fuel consumption over the reference cycle (NEDC) are identified. At a second step, the CO₂ benefit from the optimisation of these factors is quantified, through simulations of 6 different passenger cars commonly found in the European fleet. For the simulations Advisor 2002 was employed and validated against published type approval data. The analysis indicated that substantial reductions in vehicle weight, tyre rolling resistance and engine efficiency are necessary to reach even the 2008 target. A 10% reduction in average vehicle weight combined with 10% better aerodynamic characteristics, 20% reduced tyre rolling resistance and a 7.5% increase in average powertrain efficiency can lead to CO₂ reductions of approximately 13% (about 138 g/km based on 2007–2008 fleet-wide performance). Complying with the 130 g/km within the next six-year timeframe will be a rather difficult task and additional technical measures appear to be necessary.     

An experimental investigation of hydrogen-enriched air induction in a diesel engine system

Diesel engines are the most trusted power sources in the transportation industry. They intake air and emit, among others, the pollutants _NOX${\mathrm{NO}}_X$ and particulate matter. Continuous efforts and tests have tried to reduce fuel consumption and exhaust emissions of internal combustion engines. Alternative fuels are key to meeting upcoming stringent emission norms. We study hydrogen as an air-enrichment medium with diesel as an ignition source in a stationary diesel engine system to improve engine performance and reduce emissions. Stationary engines can be operated with less fuel than neat diesel operations, resulting in lower smoke levels and particulate emissions. Hydrogen (_H2)$({\mathrm{H}}_2)$-enriched air systems in diesel engines enable the realization of higher brake thermal efficiency, resulting in lower specific energy consumption (SEC). _NOX${\mathrm{NO}}_X$ emissions are reduced from 2762 to 515 ppm with 90% hydrogen enrichment at 70% engine load. At full load, _NOX${\mathrm{NO}}_X$ emission marginally increases compared to diesel operation, while both smoke and particulate matter are reduced by about 50%. The brake thermal efficiency increases from 22.78% to 27.9% with 30% hydrogen enrichment. Thus, using hydrogen-enriched air in a diesel engine produces less pollution and better performance.     

Numerical and experimental study of soot formation in laminar diffusion flames burning simulated biogas fuels at elevated pressures

The effects of pressure and composition on the sooting characteristics and flame structure of laminar diffusion flames were investigated. Flames with pure methane and two different methane-based, biogas-like fuels were examined using both experimental and numerical techniques over pressures ranging from 1 to 20 atm. The two simulated biogases were mixtures of methane and carbon dioxide with either 20% or 40% carbon dioxide by volume. In all cases, the methane flow rate was held constant at 0.55 mg/s to enable a fair comparison of sooting characteristics. Measurements for the soot volume fraction and temperature within the flame envelope were obtained using the spectral soot emission technique. Computations were performed by solving the unmodified and fully-coupled equations governing reactive, compressible flows, which included complex chemistry, detailed radiation heat transfer and soot formation/oxidation. Overall, the numerical simulations correctly predicted many of the observed trends with pressure and fuel composition. For all of the fuels, increasing pressure caused the flames to narrow and soot concentrations to increase while flame height remained unaltered. All fuels exhibited a similar power-law dependence of the maximum carbon conversion on pressure that weakened as pressure was increased. Adding carbon dioxide to the methane fuel stream did not significantly effect the shape of the flame at any pressure; although, dilution decreased the diameter slightly at 1 atm. Dilution suppressed soot formation at all pressures considered, and this suppression effect varied linearly with CO₂${\text{CO}}_2$ concentration. The suppression effect was also larger at lower pressures. This observed linear relationship between soot suppression and the amount of CO₂${\text{CO}}_2$ dilution was largely attributed to the effects of dilution on chemical reaction rates, since the predicted maximum magnitudes of soot production and oxidation also varied linearly with dilution.     

CO2 emissions of Turkish manufacturing industry: A decomposition analysis

In this study, CO₂ emissions of Turkish manufacturing industry are calculated by using the fuel consumption data at ISIC revision 2, four digit level. Study covers 57 industries, for the 1995–2001 period. Log Mean Divisia Index (LMDI) method is used to decompose the changes in the CO₂ emissions of manufacturing industry into five components; changes in activity, activity structure, sectoral energy intensity, sectoral energy mix and emission factors. Mainly, it is found that changes in total industrial activity and energy intensity are the primary factors determining the changes in CO₂ emissions during the study period. It is also indicated that among the fuels used, coal is the main determining factor and among the sectors, 3710 (iron and steel basic industries) is the dirtiest sector dominating the industrial CO₂ emissions in the Turkish manufacturing industry.     

Hydrogen perspectives in Italy: Analysis of possible deployment scenarios

The paper analyses Italian hydrogen scenarios to meet climate change, environmental and energy security issues. An Italy-Markal model was used to analyse the national energy–environment up to 2050. About 40 specific hydrogen technologies were considered, reproducing the main chains of production, transport and consumption, with a focus on transport applications. The analysis is based on the Baseline and Alternative scenario results, where hydrogen reaches a significant share. The two scenarios constitute the starting points to analyse the hydrogen potential among the possible energy policy options. The energy demand in the Baseline scenario reaches values around 240 Mtoe at 2030, with an average annual growth of 0.9%. The Alternative scenario reduces consumption down to 220 Mtoe and stabilizes the _CO2${\mathrm{CO}}_2$ emissions. The Alternative scenario expects a rapid increase of hydrogen vehicles in 2030, up to 2.5 million, corresponding to 1 Mtoe of hydrogen consumption. A sensitivity analysis shows that the results are rather robust.     

The impact of fiscal and other measures on new passenger car sales and CO2 emissions intensity: Evidence from Europe

This paper examines the impact of national fiscal measures in the EU (EU15) on passenger car sales and the CO₂ emissions intensity of the new car fleet over the period 1995–2004. CO₂ emissions and energy consumption from road transport have been increasing in the EU and as a result since 1999 the EU has attempted to implement a high profile policy strategy to address this problem at European level. Less prominent is the fact that Member States apply vehicle and fuel taxes, which may also be having an impact on the quantity of passenger cars sold and their CO₂ emissions intensity. Diesel vehicle sales have increased appreciably in many countries over the same period and this study makes a first attempt to examine whether Member State fiscal measures have influenced this phenomenon. This work uses a panel dataset to investigate the relationship between national vehicle and fuel taxes on new passenger car sales and the fleet CO₂ emissions intensity in EU15 over a 10-year period. Our results show that national vehicle and fuel taxes have had an impact on passenger car sales and fleet CO₂ emissions intensity and that different taxes have disparate effects.     

Causalities between CO2, electricity,and other energy variables during phase I and phase II of the EU ETS

The topic of this article is the analysis of the interplay between daily carbon, electricity and gas price data with the European Union Emission Trading System (EU ETS) for CO₂ emissions. In a first step we have performed Granger causality tests for Phase I of the EU ETS (January 2005 until December 2007) and the first year of Phase II of the EU ETS (2008). The analysis includes both spot and forward markets—given the close interactions between the two sets of markets. The results show that during Phase I coal and gas prices, through the clean dark and spark spread, impacted CO₂ futures prices, which in return Granger caused electricity prices. During the first year of the Phase II, the short-run rent capture theory (in which electricity prices Granger cause CO₂ prices) prevailed. On the basis of the qualitative results of the Granger causality tests we obtained the formulation testable equations for quantitative analysis. Standard OLS regressions yielded statistically robust and theoretically coherent results.     

An experimental study on performance and emission characteristics of a hydrogen fuelled spark ignition engine

In the present paper, the performance and emission characteristics of a conventional four cylinder spark ignition (SI) engine operated on hydrogen and gasoline are investigated experimentally. The compressed hydrogen at 20  MPa has been introduced to the engine adopted to operate on gaseous hydrogen by external mixing. Two regulators have been used to drop the pressure first to 300 kPa, then to atmospheric pressure. The variations of torque, power, brake thermal efficiency, brake mean effective pressure, exhaust gas temperature, and emissions of _NOx${\mathrm{NO}}_x$, CO, _CO2${\mathrm{CO}}_2$, HC, and _O2${\mathrm{O}}_2$ versus engine speed are compared for a carbureted SI engine operating on gasoline and hydrogen. Energy analysis also has studied for comparison purpose. The test results have been demonstrated that power loss occurs at low speed hydrogen operation whereas high speed characteristics compete well with gasoline operation. Fast burning characteristics of hydrogen have permitted high speed engine operation. Less heat loss has occurred for hydrogen than gasoline. _NOx${\mathrm{NO}}_x$ emission of hydrogen fuelled engine is about 10 times lower than gasoline fuelled engine. Finally, both first and second law efficiencies have improved with hydrogen fuelled engine compared to gasoline engine. It has been proved that hydrogen is a very good candidate as an engine fuel. The obtained data are also very useful for operational changes needed to optimize the hydrogen fueled SI engine design.     

Analysis of the benefits of carbon credits to hydrogen addition to midsize gas turbine feedstocks

The addition of hydrogen to the natural gas feedstocks of midsize (30–150 MW) gas turbines was analyzed as a method of reducing nitrogen oxides (_NOx)$({\mathrm{NO}}_x)$ and _CO2${\mathrm{CO}}_2$ emissions. In particular, the costs of hydrogen addition were evaluated against the combined costs for other current _NOx${\mathrm{NO}}_x$ and _CO2${\mathrm{CO}}_2$ emissions control technologies for both existing and new systems to determine its benefits and market feasibility. Markets for _NOx${\mathrm{NO}}_x$ emissions credits currently exist in California and the Northeast States and are expected to grow. Although regulations are not currently in place in the United States, several other countries have implemented carbon tax and carbon credit programs. The analysis thus assumes that the United States adopts future legislation similar to these programs. Therefore, potential sale of emissions credits for volunteer retrofits was also included in the study. It was found that hydrogen addition is a competitive alternative to traditional emissions abatement techniques under certain conditions. The existence of carbon credits shifts the system economics in favor of hydrogen addition.     

Methane emissions by Chinese economy: Inventory and embodiment analysis

Concrete inventories for methane emissions and associated embodied emissions in production, consumption, and international trade are presented in this paper for the mainland Chinese economy in 2007 with most recent availability of relevant environmental resources statistics and the input–output table. The total CH₄ emission by Chinese economy 2007 estimated as 39,592.70 Gg is equivalent to three quarters of China's CO₂ emission from fuel combustion by the global thermodynamic potentials, and even by the commonly referred lower IPCC global warming potentials is equivalent to one sixth of China's CO₂ emission from fuel combustion and greater than the CO₂ emissions from fuel combustion of many economically developed countries such as UK, Canada, and Germany. Agricultural activities and coal mining are the dominant direct emission sources, and the sector of Construction holds the top embodied emissions in both production and consumption. The emission embodied in gross capital formation is more than those in other components of final demand characterized by extensive investment and limited consumption. China is a net exporter of embodied CH₄ emissions with the emission embodied in exports of 14,021.80 Gg, in magnitude up to 35.42% of the total direct emission. China's exports of textile products, industrial raw materials, and primary machinery and equipment products have a significant impact on its net embodied emissions of international trade balance. Corresponding policy measures such as agricultural carbon-reduction strategies, coalbed methane recovery, export-oriented and low value added industry adjustment, and low carbon energy polices to methane emission mitigation are addressed.     

Synthesis and hydrogen storage properties of carbon nanotubes

Multi-walled carbon nanotubes (MWNT) have been synthesized by chemical vapor decomposition of acetylene over rare-earth (RE) based _AB2${\mathrm{AB}}_2$ alloy hydride catalysts. The _AB2${\mathrm{AB}}_2$ alloy hydride catalysts have been prepared by hydrogen decrepitation technique and characterized by scanning electron microscopy. The advantage of this novel method of obtaining catalysts has been discussed. The as-grown carbon nanotubes were purified by acid and heat treatments and characterized using powder X-ray diffraction, transmission electron microscopy, scanning electron microscopy, thermo gravimetric analysis and Raman spectroscopy. Hydrogen adsorption measurements were carried out on as-prepared and purified MWNT in the temperature range of 143–373 K and pressure range of 10–100 bar using a high pressure hydrogen adsorption setup and the results have been discussed. A maximum hydrogen storage capacity of 3.5 wt% is obtained for purified MWNT prepared with _DyNi2${\mathrm{DyNi}}_2$ alloy hydride catalyst at 143 K and 75 bar.     

Hydrogen production from Chlamydomonas reinhardtii biomass using a two-step conversion process: Anaerobic conversion and photosynthetic fermentation

Chlamydomonas reinhardtii UTEX 90 accumulated 1.45 g dry cell weight and 0.77 g starch/L during photosynthetic growth using TAP media at 25 ^°C${}^{°}\mathrm{C}$ in presence of 2% _CO2${\mathrm{CO}}_2$ for 3 days. C. reinhardtii biomass was concentrated and then converted into hydrogen and organic acids by anaerobic fermentation with Clostridium butyricum. Organic acids in the fermentate of algal biomass were consecutively photo-dissimilated to hydrogen by Rhodobacter sphaeroides KD131. In the concentrated algal biomass 52% of the starch was hydrolyzed to 37.1 mmol _H2${\mathrm{H}}_2$/L-concentrated algal biomass and 13.6, 25.5, 7.4 and 493 mM of formate, acetate, propionate, and butyrate, respectively by C. butyricum. R. sphaeroides KD131 evolved 5.72 mmol _H2${\mathrm{H}}_2$ per ml-fermentate of algal biomass under illumination of 8 klux at 30 ^°C${}^{°}\mathrm{C}$. Only 80% of the organic acids, mainly butyrate, were hydrolyzed during photo-incubation. During anaerobic conversion, 2.58 mol _H2/mol${\mathrm{H}}_2/\mathrm{mol}$ starch–glucose was evolved using C. butyricum and then 5.72 mol _H2/L${\mathrm{H}}_2/\mathrm{L}$-anaerobic fermentate was produced by R. sphaeroides KD131. Thus, the two-step conversion process produced 8.30 mol _H2${\mathrm{H}}_2$ from 1 mol starch–glucose equivalent algal biomass via organic acids.     

The ignition,combustion and flame structure of carbon monoxide/hydrogen mixtures. Note 1: Detailed kinetic modeling of syngas combustion also in presence of nitrogen compounds

The kinetic characterization of the _H2/CO${\mathrm{H}}_2/\mathrm{CO}$ system is of interest right now due mainly to its role in sustainable combustion processes. The aim of this paper is to revise and validate a detailed kinetic model of hydrogen and carbon monoxide mixture combustion with particular focus not only on _NOx${\mathrm{NO}}_x$ formation but also on interactions with nitrogen species. Model predictions and experimental measurements are discussed and compared across a wide range of operating conditions. This study moves from the detailed analysis of species profiles in syngas oxidation in flow reactor and laminar premixed flames to global combustion properties (ignition delay times and laminar flame speeds) by referring to a large set of literature data. According to recent literature, the validation of the kinetic scheme confirmed there was a need to slightly modify the kinetic parameters of two relevant _CO2${\mathrm{CO}}_2$ formation reactions (CO+OH=_CO2+H$\mathrm{CO}+\mathrm{OH}={\mathrm{CO}}_2+\mathrm{H}$ and CO+O+M=_CO2+M$\mathrm{CO}+\mathrm{O}+\mathrm{M}={\mathrm{CO}}_2+\mathrm{M}$) and of reaction HONO+OH=_NO2+_H2O$\mathrm{HONO}+\mathrm{OH}={\mathrm{NO}}_2+{\mathrm{H}}_2\mathrm{O}$.