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Abstract Hydrogen sulphide is likely to become more common in produced hydrocarbon fluids, as the exploitation of deep reservoirs increases and unconventional resources get recovered significantly, such as heavy oils or bitumen. Hydrogen sulphide presence in produced oil and gas results in operational, environmental and treatment problems. Therefore, understanding the origin and the amount of hydrogen sulphide in petroleum reservoirs has great importance for petroleum engineers. Three natural processes are set forth to explain the generation of H 2 S in reservoirs: bacterial sulphate reduction, thermal cracking and thermochemical sulphate reduction (TSR). It is the TSR that leads to the largest amount of H 2 S. This phenomenon involves hydrocarbon oxidation and sulphate reduction and produces as by-products, hydrogen sulphide, carbon dioxide, carbonate minerals and heavy organo-sulphur compounds. The reaction mechanisms of TSR, as well as its kinetics, are not yet fully understood. In this paper, we checked the thermodynamic feasibility of TSR, at temperatures prevailing in the reservoirs where TSR is encountered. Firstly, we calculated the Gibbs energy of the reactions proposed by Worden and Smalley (Worden R.H. and Smalley P.C., 1996, H 2 S producing reactions in deep carbonate gas reservoirs: Khuff Formation, Abu Dhabi, Chem. Geol., 133, p. 157–171). We concluded that they are thermodynamically possible from 25 °C, confirming thermodynamic data published by Anisimov (Anisimov L., 1978, Conditions of abiogenic reduction of sulfates in oil and gas bearing basins, Geochem. Int., 15, p. 63) and Yue and co-workers (Yue C., Li S., Ding K., Zhong N., 2003, Study of thermodynamics and kinetics of CH4–CaSO 4 and H 2 S–Fe 2 O 3 systems, Chinese J. chem. Eng., 11, (6), p.696–700., Yue C., Li S., Ding K., Zhong N., 2006, Thermodynamics and kinetics of reaction between C1–C3 hydrocarbons and calcium sulfate in deep carbonate reservoirs, Geochem. J., 40, 87–94). Secondly, we used a non-stoichiometric approach without any pre-requisite chemical scheme this time. We calculated the Gibbs Energy of chemical systems composed by hydrocarbons, sulphur, anhydrite and water. The minimization of the Gibbs Energy lead to find the most probable chemical systems at steady state. Our theoretical results are consistent with the chemical schemes set forth for TSR by Orr (Orr W., 1977, Changes in Sulfur Content and Isotopic Ratios of Sulfur during Petroleum Maturation — study of Big Horn Basin Paleozoic Oils, in R. Campo and J. Goni Eds, Advances in onorganic geochemistry, Madrid Spain, Enadimsa, p. 571–595), by Worden and Smalley (Worden R.H. and Smalley P.C., 1996, H 2 S producing reactions in deep carbonate gas reservoirs: Khuff Formation, Abu Dhabi, Chem. Geol., 133, p. 157–171) and by Machel (Machel H.G., 2001, Bacterial and thermochemical sulfate reduction in diagenetic settings — old and new insights, Sedimentary Geology, 140, p. 143–175). Moreover, they are in concordance with some in-situ observations: anhydrite and hydrocarbon consumption with simultaneous formation of calcite, hydrogen sulphide and water. Our results showed as well that the larger the number of the carbon atoms in the reactant hydrocarbons, the more irreversible the reaction is.

Abstract In this paper, we examine the time-varying causal relationship between green bonds and other assets including US conventional bonds, WilderHill clean energy (equity) index, and CO2 emission allowances price during the period spanning from 30 July 2014 to 10 February 2020. We apply the novel time-varying Granger causality test (Shi et al. 2018) based on the recursive evolving algorithm introduced by Phillips et al. (2015a, 2015b) for controlling financial bubbles to detect real–time causality, detecting possible changes in the causal direction and dating financial turbulences, The study based on this algorithm reveals a significant causality running from the US 10-year Treasury bond index to green bonds starting from the end of the year 2016 until the end of the sample period. Besides, we find that the link CO2 emission allowances price causing green bonds is significant from the beginning of the sample period to the end of the year 2015. Furthermore, by using the recursive-evolving causality algorithm of the Shi et al. (2018) test, we find that the causality running from the clean energy index to green bonds is very limited to the year 2019. On the other hand, there is no significant causality running from green bonds to all considered assets, indicating no predictive power for this asset in its proper domain, which is not yet examined in the literature.

Abstract There is a growing use of metamodels to evaluate building energy performance. However, current metamodeling approaches lack a common foundation. The aim of this work was to develop a general metamodel for building energy performance. Based on the premise that each building element can have an impact on energy performance, our general metamodel assumes that the overall impact is a polynomial function of the individual impacts. The model includes time-dependent parameters such as the solar heat gain coefficient and energy system efficiency. A model derived from the general model was tested on an office located in Paris. Energy needs and consumption, the cost of energy consumption and the CO2 emissions for heating and cooling were analyzed. The study highlighted the significant impact of the choice of the performance criteria in evaluating the efficiency of building design solutions. The metamodel represents a fast way to perform calculations with an accuracy close to that of dynamic simulations. It can be used as a basis to perform parametric studies and for future building energy regulations.

The phosphate (P) fertilizer industry generates a highly hazardous and acidic wastewater. The present study reports the evaluation of an integrated precipitation and Enhanced Biological Phosphorus Removal (EBPR) process for the treatment of fertilizer plant wastewater and effluent detoxification, assessed by microtoxicity and seed germination tests. Effluent samples were collected from a local P fertilizer industry and were characterized by their high fluoride and P content. First, the samples were pre‐treated by precipitation of P and fluoride ions using hydrated lime. The resulting low‐fluoride and phosphorus effluent was then treated with the EBPR process to monitor the simultaneous removal of carbon, nitrogen, and phosphorus. Phosphorus removal included a two‐stage anaerobic/aerobic system operating under continuous flow. Pre‐treated wastewater was added to the activated sludge and operated for 160 days in the reactor. The operating strategy included increasing the organic loading rate from 0.3 to 1.2 g chemical oxygen demand (COD)/L day. The stable and high removal rates of COD, NH4+‐N, and PO43−‐P were then recorded. The mean concentrations of the influent were approximately 3600 mg COD/L, 60 mg N/L and 14 mg P/L, which corresponded to removal efficiencies of approximately 98%, 86%, and 92%, respectively. The microtoxicity of the treated wastewater was then monitored by LUMIStox and its phytotoxicity was investigated on cress, tomato, wheat, maize, ryegrass, and alfalfa seed germination. LUMIStox tests showed that treatment allowed a significant toxicity removal. Moreover, the untreated wastewater inhibited the species germination even when diluted 10 times, whereas a positive effect of treated wastewater was noticed. © 2013 American Institute of Chemical Engineers Environ Prog, 33: 463–471, 2014

Abstract Batteries are responsible for the major share of costs of electric vehicles (EVs). However, they are idle most of the time during vehicle use and expected to retain a significant capacity when discarded from vehicle use. As a result, they may provide an additional value during and after their vehicle life, helping to reduce their total costs of ownership. We use a dynamic model to evaluate three competing approaches of using EV batteries for grid applications. These are (1) batteries installed in EVs, also known as vehicle-to-grid (V2G), as well as (2) used and (3) new batteries installed in stationary energy storage systems (ESS), which we refer to as battery-to-grid (B2G). We find that none of the approaches is likely to be implemented on a large scale as the anticipated revenues barely (if at all) offset the additional costs incurred by the corresponding applications.

The demand for reduced pollutant emissions has motivated various technological advances in passenger car diesel engines. This paper presents a study comparing two fuel injection systems and analyzing their combustion noise and pollutant emissions. The abilities of different injection strategies to meet strict regulations were evaluated. The difficult task of maintaining a constant specific fuel consumption while trying to reduce pollutant emissions was the aim of this study. The engine being tested was a 0.287-liter single-cylinder engine equipped with a common-rail injection system. A solenoid and a piezoelectric injector were tested in the engine. The engine was operated under low load conditions using two injection events, high EGR rates, no swirl, three injection pressures and eight different dwell times. Four injector nozzles with approximately the same fuel injection rate were tested using the solenoid injection system (10 and 12 orifice configuration) and piezoelectric system (6 and 12 orifice design). The injection system had a significant influence on pollutant emissions and combustion noise. The piezoelectric injector presented the best characteristics for future studies since it allows for shorter injection durations and greater precision, which means smaller fuel mass deliveries with faster responses.

AbstractThe unhairing step in leather manufacture generates a highly hazardous and alkaline wastewater. This article reports the evaluation of an activated sludge system for the treatment of unhairing wastewater and effluent detoxification, assessed by seed germination tests.The activated sludge system reactor was fed for 112 days with diluted unhairing effluent; the operation strategy included increasing the organic loading rate (OLR) from 0.7 to 1.6 g chemical oxygen demand (COD) L−1 d−1. COD and suspended solids (SS) removal efficiencies were up to 85 and 80%, respectively, for an OLR lower than 1.4 g COD L−1 d−1.Sulphide removal efficiency was ∼90%, as sulphide was oxidized to other species such as sulphate. The biological oxidation of thiosulphates into tetrathionates was also investigated.The effect of untreated and treated unhairing wastewater on seed germination of maize, sorghum, and wheat was examined. Treatment decreased the phytotoxicity of the wastewater. Indeed, germination was inhibited when effluent dilution was lower than 90% of untreated wastewater, whereas a positive effect of treated wastewater was noticed.Phytotoxicity assays showed that biological treatment of unhairing wastewater contributed to a decrease in toxicity of the effluent. © 2010 American Institute of Chemical Engineers Environ Prog, 2011

Purpose Waste generation poses a significant environmental challenge in the United Arab Emirates due to the rapid urbanization, population growth and industrialization witnessed in recent decades. As a result, there has been a substantial surge in waste production. To fulfil its sustainability and circular economy aspirations in various economic domains, the UAE must prioritize efficient waste management. The purpose of this study is to assess the environmental and energy efficiency of the UAE’s economic sectors particularly within its vital energy sectors, which encompass crude oil, natural gas and mining, manufacturing and electricity, by gauging their adherence to sustainability and circularity objectives. Design/methodology/approach The authors used the data envelopment analysis input–output model to identify sectors that exhibit strong performance as well as those that are falling behind. Findings Based on this study, the agriculture, the crude oil, natural gas and mining sectors and financial services and banking were found to be the most efficient. The results of this study concluded that the UAE is making progress toward achieving its sustainability and circularity objectives; however, the findings suggest that more effort is needed to fully realize these goals. Originality/value By identifying high-performing and underperforming sectors, decision-makers can prioritize efforts to enhance sustainability and circularity in area of greatest need in the economy.

This paper attempts to analyse the role of building energy efficiency (BEE) in China in addressing climate change mitigation. It provides an analysis of the current situation and future prospects for the adoption of BEE technologies in Chinese cities. It outlines the economic and institutional barriers to large-scale deployment of the sustainable, low-carbon, and even carbon-free construction techniques. Based on a comprehensive overview of energy demand characteristics and development trends driven by economic and demographic growth, different policy tools for cost-effective CO(2) emission reduction in the Chinese construction sector are described. We propose a comprehensive approach combining building design and construction, and the urban planning and building material industries, in order to drastically improve BEE during this period of rapid urban development. A coherent institutional framework needs to be established to ensure the implementation of efficiency policies. Regulatory and incentive options should be integrated into the policy portfolios of BEE to minimise the efficiency gap and to realise sizeable carbon emissions cuts in the next decades. We analyse in detail several policies and instruments, and formulate relevant policy proposals fostering low-carbon construction technology in China. Specifically, Our analysis shows that improving building energy efficiency can generate considerable carbon emissions reduction credits with competitive price under the CDM framework.