This article presents key energy use figures and explores the energy saving potentials in office buildings across Europe by simulating several currently available scenarios. The information provided in this research work is based on a review of relevant literature and the results of EnergyPlus simulations of a reference office building that can be considered as a representative office building across Europe. Three locations were selected to represent the three climate zones in which Europe was divided.Lighting has been pointed out as an area with significant improvement potentials. These improvements have been investigated by using two scenarios with different lighting control systems. In both cases and regardless of the location of the office building, the energy savings were achieved with already existing technology and will bring important reductions in the overall energy bill.Two further aspects were investigated in this work: the first one is an improvement of the insulation of the windows and the external walls (U-value) and the second one the orientation of the building.Unlikely to the lighting improvements, the location of the buildings highly influences the amount of energy required by HVAC systems. It is observed that higher insulation factors are recommended in cold and medium climate zones while they should be carefully chosen in the warmer climate zones. Office buildings constructed in warm climate zones are subjected to higher heat gains that cannot be easily released from buildings within a well-insulated envelope. Consequently, the energy demand for cooling purposes is increased, affecting the overall energy consumption and the economic performance of the building. (c) 2013 Elsevier B.V. All rights reserved.

Steam methane reforming (SMR) is one of the most promising processes for hydrogen production. Several studies have demonstrated its advantages from the economic viewpoint. Nowadays process development is based on technical and economical aspects; however, in the near future, the environmental impact will play a significant role in the design of such processes. In this paper, an SMR process is studied from the viewpoint of overall environmental impact, using an exergoenvironmental analysis. This analysis presents the combination of exergy analysis and life cycle assessment. Components where chemical reactions occur are the most important plant components from the exergoenvironmental point of view, because, in general, there is a high environmental impact associated with these components. This is mainly caused by the exergy destruction within the components, and this in turn is mainly due to the chemical reactions. The obtained results show that the largest potential for reducing the overall environmental impact is associated with the combustion reactor, the steam reformer, the hydrogen separation unit and the major heat exchangers. The environmental impact in these components can mainly be reduced by improving their exergetic efficiency. A sensitivity analysis for some important exergoenvironmental variables is also presented in the paper.

In this paper, an advanced exergoenvironmental analysis is conducted for a steam methane reforming process for the production of hydrogen. The approach for calculating pollutant formation is generalized and the assumptions required for applying the analysis are discussed in detail. These are the main contributions of this work to the development of exergy-based methods for the analysis of energy-intensive chemical processes. In an advanced exergoenvironmental analysis, the environmental impact associated with the exergy destruction within a component as well as the component-related environmental impact and a component-related pollutant formation are split into unavoidable/avoidable and endogenous/exogenous parts. This splitting improves our understanding of the sources of thermodynamic inefficiencies and their effect to the formation of environmental impacts and pollutants, and facilitates a subsequent improvement of the overall process. Finally, some improvement options developed on the basis of the results of the advanced exergoenvironmental analysis are discussed.

Catalytic briquettes were prepared using a low-rank coal as carbon precursor and vanadium compounds, i.e. V2O5 and petroleum coke ash (PCA), as the source of the active phase. The catalytic briquettes presented herein offer a feasible low-cost possibility for flue gas cleaning in medium and small industrial facilities. For their preparation, coal was first pyrolysed, then blended with tar pitch and cold pressed to produce the cylindrical briquettes. Pressed briquettes were submitted then to pyrolysis and activation in the presence of steam or CO2, at different temperatures and residence times. Activated briquettes were functionalized by means of HNO3 and H2SO4-wet oxidation. Physical and chemical properties of the produced briquettes were evaluated using N2 adsorption, Raman spectroscopy, temperature programmed desorption (TPD), photoelectron spectroscopy (XPS) and NH3 chemisorption. Important mechanical properties such as Impact Resistance Index (IRI) and Water Resistance Index (WRI) were also determined for this series of briquettes. Briquettes showed considerable activity in the SCR of NO in a wide temperature range (75–350°C) and high selectivity towards N2. The several steps involved in the preparation of the catalytic briquettes influence both their structural–chemical and mechanical properties, as well as their catalytic activity in the SCR of NO. Thus, the evaluation of these parameters was found to be crucial for future scale-up and applications.

A carbon coated monolith was modified by different oxidative treatments to introduce different oxygen surface groups. Three kinds of liquid oxidizing agents (HNO3, H2SO4 and H2O2) were used at different temperatures and residence times. The resulted oxidized activated carbon coatings were impregnated with 3% V wt on carbon and tested for the SCR of NO with NH3 in a temperature range of 150–350°C. The performance of the carbon coated catalysts was assessed by characterization of supports and catalysts through their textural and chemistry surface properties. In this sense, regarding the preparation of the catalysts, oxidation process plays itself a promoting role in the formation of oxygen surface groups that to a certain extent improves the catalytic activity. Inorganic acid, especially HNO3 oxidation increases mainly the carboxyl and lactone groups whereas H2O2 oxidation significantly increases oxygen surface groups attributed to phenol, and carbonyl/quinine groups.Generally, NO reduction activity is increased when fresh catalyst surface acidity increases and vanadium is doped on it. HNO3 oxidized samples are able to fix higher amounts of vanadium in comparison to other oxidized monoliths. This fact can be attributed to the fact that the fresh catalyst surface acidity caused by the HNO3 oxidation has a promoting role to favour well anchored and distributed vanadium onto its surface. Oxidation as well as vanadium impregnation process decrease BET surface area and micropore volume of supports. However, the chemistry surface developed for the oxidation process seems to be much more important promoting SCR activity and consequently a higher catalytic activity is observed for oxidized samples.

CO2 capture and storage from energy conversion systems is widely known as a potential method to reduce CO2 emissions to the atmosphere and to limit the impact of energy use on the climate. This study uses the exergoeconomic and exergoenvironmental analyses to provide an evaluation from an economic and environmental perspective, respectively, of an advanced zero emission plant (AZEP) and to reveal possible ways to improve the overall effectiveness of the plant. The AZEP, which is an oxy-fuel power plant, is evaluated and compared with a reference plant without CO2 capture. The exergoeconomic analysis shows a high increase in cost for the AZEP, due to the introduction of the membrane technology, while on the other hand, its environmental impact is significantly reduced. When compared with competitive alternatives, like chemical absorption-a post-combustion technology for CO2 capture-the oxy-fuel plant achieves lower relative cost and exergy expenditures.

The influence of two different washcoats deposited on ceramic honeycombs (alumina and carbon) on the catalytic and mechanical properties of catalysts are examined in this work. A series of carbon and alumina washcoated samples was prepared through a dip-coating method and subsequently cured and treated to reach a suitable chemistry surface. Carbon-coated monoliths present a high washcoat homogeneity, high integrity and a suitable chemistry surface that favour NO reduction at low temperatures. The carbon washcoat was bonded perfectly to the ceramic monoliths. The high adherence between both materials, checked by vibrational tests, provides higher resistance indexes against axial compression and prevents crack propagation. Both facts are a consequence of the high mechanical strength of the catalyst. On the other hand, alumina coatings present better temperature resistance, although their adherence to ceramic monoliths is not as good as in carbon-coated samples. The properties of alumina coatings are strongly dependent on the slurry viscosities, which influence the integrity of the washcoat, mechanical properties and even NO conversion. Both series of catalysts have shown a good NO conversion under on-board conditions, although the key parameters of each washcoat are completely different.

Carbon-coated catalysts doped with tungsten and vanadia oxides with different V and W loadings have been prepared by the ionic exchange method and characterized. The surface, structure and composition have been investigated by XPS, Raman, N2 sorption at 77K, TPD-NH3 and reactivity tests for the SCR of NO with NH3 at low temperatures. Under reaction conditions, NO conversions were found to go through a maximum with vanadia surface coverage at approximately half a monolayer. The observed decrease in the SCR activity at higher vanadia loadings can be attributed to either a loss of dispersion or loss of textural properties. Maximum NO conversion is ascribed to the higher Brönsted proton acidity (V4+) of the centres that decreases with increasing vanadia loadings up to 3wt% loading due to the increase of V4+/V5+ ratio.Large amounts of tungsten (5%, w/w) upon or before addition of vanadia do not provide an enhancement of activity. The results indicate that W addition increases surface acidity leading to stronger Brönsted or even Lewis acid centre creation.

The influence of treating carbon with sulphuric and nitric acids on the activity of a carbon-based briquette catalyst for NO reduction with NH3 was examined in a fixed-bed reactor at low temperature (150°C). The briquette catalysts were prepared from a low-rank coal and a commercial tar pitch. The active phase was impregnated from a suspension of ashes of coke petroleum by means of an equilibrium adsorption method. The catalytic behaviour of NO reduction over acid treated briquettes was found to vary with the surface characteristics of the carbon support. This suggests that the number of oxygen-containing sites as well as vanadium load and dispersion affect the reaction activity. In the presence of oxygen, the SCR activity is enhanced with a nitric acid treatment, activity is promoted by the presence of acidic surface groups such as carboxyl and lactone, which can help not only to create a reservoir of reactants on the catalysts surface but also to improve the dispersion or even increase the amount of vanadium loading. Therefore, the results of this study suggest that the formation of acidic sites on the surface is an important step for NO reduction with NH3 over carbon-based catalysts. Additional techniques such as XPS and TPD to characterize the oxygen surface and those such as N2 adsorption to characterize the textural properties were also used in this study.

Exhaust gasses from small and medium stationary sources contain NO, that will be regulated by new European legislation in the coming years. Among all the processes the SCR-NH3 seems to be the more promising one. However, the application of commercial catalysts to these new facilities presents some drawbacks such as the high and narrow operation temperature, its low withdraw to SO, or its high cost production. In order to improve this technology, in previous works, carbon-supported catalytic briquettes have shown a good kinetic performance under the above commented conditions. In this study, other aspects such as thermal stability, long-term performance, spatial velocity influence and mechanical resistance were evaluated. Finally, a simple economic assessment was carried out providing a three times lower cost production than commercial catalysts. From all the data collected, there are some evidences that these catalyst briquettes will have a good performance in small and medium facilities, being an interesting alternative to commercial ones. (C) 2007 Elsevier B.V. All rights reserved.

The kinetics of the selective catalytic reduction of NO in the presence of vanadium loaded carbon-based catalysts has been studied, by means of different techniques, such as transient response analysis, temperature programmed desorption and DRIFT spectrometry. The results point out to a reaction mechanism involving adsorbed species of ammonia, which react with the NO from the gas phase. The role of oxygen will be the regeneration of the spent catalytic sites. Finally, the Mars van Krevelen kinetic model was successfully used to fit the experimental data.

Selective catalytic reduction (SCR) with NH3 and most probably with urea is unanimously regarded as one of the most promising technologies for the abatement of NO, on-board. For this application at low temperatures. carbon-based monolithic catalysts have been prepared using, a blend of polymers on cordieritc monoliths, doped with two different vanadium compounds and two different loadings (3 and 5%). The active phase precursors were either the ashes of a petroleum coke (PCA) ora commercial NH4VO3. An experimental design was carried out to study the reduction of NO emissions, the selectivity towards N-2 and the release of ammonia-slip in the outlet reactor gasses. Both primary measures (temperature. gas space velocity per hour (GSVH) and the molar ratio of NH3/NO) as well as secondary SNR influences were evaluated using a 2(3) factorial design for the two types of catalysts. Polinomial modellings were deducted from statistical analysis of the experiments, and a good agreement between models and measured data was obtained. The evaluation showed that the temperature is the variable which has a greater influence on all the response variables studied. Spatial velocity shows approximately an equal importance on NO conversion and selectivity towards N-2 whereas the molar ratio of NH3/NO is only an important factor in the interaction to other parameters. Catalysts prepared using PCA have similar catalytic behaviour than those prepared with NH4VO3. Although they show a slightly lower catalytic activity, similar selectivity towards N-2 and higher values of ammonia-slip.The physical-chemical features of the catalysts, analysed by N-2 physisorption, ammonia adsorption and temperature programme desorption have a close relation with the catalysts behaviour. The physical-chemical features are of key importance for achieving a considerable catalytic activity. The values of apparent activation energy calculated for the catalysts presented in this paper were similar to other carbon-based catalysts and smaller than the ones Corresponding to TiO2-supported systems. (c) 2008 Elsevier B.V All rights reserved.

A series of polymeric carbon-coated monoliths oxidized with either concentrated or 2N HNO3, H2O2 or H2SO4 and subsequently loaded with 3wt.% vanadium were prepared. The influence of the different oxidation treatment conditions on the SCR (selective catalytic reduction) catalytic activity, texture and chemical surface properties were studied. Similar pore distribution and pore volumes were observed for the four oxidized samples, indicating that surface modification of carbon supports has been successfully made without disrupting the original textural structures of activated coated monoliths. The surface chemistry created by the oxidation treatments has two effects on the catalytic activity. One of these is that higher surface acidity results in higher NO reduction up to a certain extent. The highest acidities seem to promote a sufficiently strong NH3 adsorption on the surface such that the lack of efficient desorption decreases the overall NO conversion efficiency. The other effect is that a low surface acidity does not seem to promote vanadium dispersion and fixation, thereby also resulting in decreased NO reduction efficiency.

Carbon-supported catalysts in the form of powder, briquettes and monolitos have been prepared. Powder and briquette samples have been obtained using a Spanish low-rank coal as raw material for carbon support through a pyrolysis process whereas monoliths were prepared by coating cordierite monoliths with a blend of two polymers. Vanadium was chosen as active element and impregnated by equilibrium adsorption from 1 to 8 wt% on the surface of as-prepared supports. All samples were tested in the selective catalytic reduction of NO with NH 3 as reducing agent at low temperature (150 °C), demonstrating a considerable efficiency which was enhanced mainly by oxidation treatments and an increase of vanadium loading up to vanadium agglomerates formation. The nature of carbon precursor determines the porosity development and surface chemistry of supports, what results in a different dispersion and fixation of active phase. An enhancement of NO efficiency is achieved by increasing microporosity and the amount of surface oxygen groups in pyrolysed coal whereas in polymer blend, mesoporosity and just a certain amount of surface oxygen groups should be promoted. An excess in vanadium loading decreases NO reduction efficiency because of a pore blockage and the formation of vanadium agglomeration what makes to expose a lower vanadium surface to the reactants.

In this paper, a novel method for preparing low-cost carbon-based briquettes is described. This procedure includes the briquetting of the carbon material, subsequent activation and finally an equilibrium adsorption impregnation of the active phase. A local low-rank coal was used for the preparation of the carbon briquettes, while both a model vanadium compound (V2O5) and the ashes of a petroleum coke (PCA) were used as the precursors of the active phase. The catalytic briquettes have been tested for NO reduction. The effect of a HNO3-oxidation previous to the impregnation has been also evaluated. The reduction tests have been carried out in presence of oxygen and with the addition of ammonia as reducing agent. The briquettes have shown to be active for NO reduction at low temperature (100–300 °C). Surface chemistry as well as the porous structure of the support, affect the catalyst behaviour. In general terms, higher NO reduction efficiencies were measured for the catalysts prepared using the pre-oxidised briquettes.

Carbon-based catalysts in powder, briquette and monolith forms have been prepared. Powder and briquette samples have been obtained from low-rank coal whereas monolith samples were prepared by coating cordierite monoliths with a blend of two polymers, namely, furan resin and polyethylene glycol. Vanadium was impregnated in these carbon-based catalysts by equilibrium adsorption using the ashes of a petroleum coke (PCA) as precursor and they were tested in the SCR of NO at low temperature. PCA contains around 23 % V, 3 % Fe and 3 % Ni among other transition metals and this use is an undeniable good way for its revalorisation. As-prepared catalysts have demonstrated a considerable efficiency which was enhanced by pre-oxidizing treatments and an increase of vanadium loading. The presence of oxygen surface functionalities is of key importance to achieve an adequate distribution and fixation of the active phase while an excess in vanadium loading can even cause pore blockage decreasing the total efficiency. External diffusion and pressure drop coefficients were calculated for the three kinds of catalysts. As expected, powder catalyst shows the highest pressure drop while briquette and monolith samples show lower pressure drop values with no sign of diffusion limitations. For this reason, these structurated catalysts are considered to be more suitable for industrial applications.

Carbon-based catalytic briquettes have been prepared for the reduction of NO in the presence of NH3 at low temperatures (100–250°C). In general terms, the reduction efficiency is promoted by an increase in the support porosity, and especially, by an oxidizing treatment prior to the impregnation. The apparent rate constants for the catalytic briquettes doped with the ashes of a petroleum coke are within the same order of magnitude as other catalysts for selective catalytic reduction (SCR) of NO at low temperature, demonstrating the feasibility of using them for this purpose.