Abatement Process Research Articles

Remarkable enhancement of the selective catalytic reduction of NO at low temperature by collaborative effect of ethanol and NH3 over silver supported catalyst

The NOx selective catalytic reduction (SCR) is extensively studied as an effective process for air pollutants abatement from lean burn and Diesel vehicles. In the implemented Urea-SCR technology, the NO2/NOx ratio is a key parameter that limits the deNOx efficiency at low temperature (175–250°C). We demonstrate that co-feeding of ammonia and ethanol on a Ag/Al2O3 catalyst enables a drastic enhancement of the NOx conversion at temperatures below 200°C using only NO as NOx (standard SCR condition). Even if NO2 is provided at low temperature by the NO oxidation over Ag/Al2O3 in presence of EtOH, the NOx conversion improvement is not only due to a direct reaction between NH3 and NOx, but mainly attributed to the availability of hydrogen H* species resulting from EtOH oxidation (similar to a H2 assisted NH3-SCR process). Due to the presence of remaining NH3 and NO2 (formed over Ag/Al2O3 catalyst), further deNOx efficiency improvement was obtained at low temperature by addition of a NH3-SCR catalyst (WO3/Ce-Zr). The critical dependence of the SCR process on the Diesel Oxidation Catalyst (DOC) efficiency at low temperature is thus avoided.

Modifications of the adsorption-catalytic system for organic impurities removal

The study was dedicated to optimization of the adsorption-catalytic process for abatement of volatile organic compounds (VOC), combining the adsorption of VOC at ambient temperature in the bed of the oxidation catalyst with the periodical regeneration of the catalyst by oxidation of adsorbed species at elevated temperature. The detailed mathematical model, accounting for occurrence of unsteady-state adsorption and oxidation reactions, heat and mass transfer process both in the catalyst bed and the catalyst pellets, was constructed. The good quality of the model was verified by bench experiments. The process simulation has confirmed the high efficiency of the new versions of the adsorption-catalytic processes: the process with the startup heater located directly inside the catalyst bed and the process with the system of parallel beds with non-simultaneous regeneration; these approaches give the way to significantly decrease the specific energy consumption and to level off the peaks of VOC outlet content and outlet gas temperature. The optimal values of process parameters were defined in the study. The developed process may be applied for VOC abatement in different waste gases, being especially advantageous in terms of energy consumption and operation flexibility in processing of lean vent gases with high flow rate.

MEMBRO3X, a Novel Combination of a Membrane Contactor with Advanced Oxidation (O3/H2O2) for Simultaneous Micropollutant Abatement and Bromate Minimization

Ozonation is a water treatment process for disinfection and/or micropollutant abatement. However, ozonation of bromide-containing water leads to bromate (BrO3–) formation, a potential human carcinogen. A solution for mitigating BrO3– formation during abatement of micropollutants is to minimize the ozone (O3) concentration. This can be achieved by dosing ozone in numerous small portions throughout a reactor in the presence of H2O2. Under these conditions, O3 is rapidly consumed to form hydroxyl radical (•OH), which will oxidize micropollutants. To achieve this goal, a novel process (“MEMBRO3X”) was developed in which ozone is transferred to the water through the pores of polytetrafluoroethylene (PTFE) hollow fiber membranes. When compared to the conventional peroxone process (O3/H2O2), the MEMBRO3X process shows better performance in terms of micropollutant abatement and bromate minimization for groundwater and surface water treatment. For a groundwater containing 180 μg/L bromide, a 95% abatement of the o...

Use of Low-cost Materials for Tar Abatement Process

Use of Low-cost Materials for Tar Abatement Process

Preliminary techno‐economic analysis of a multi‐bed series reactor as a simultaneous CF4 abatement and utilization process

AbstractA preliminary techno‐economic analysis combining process simulation and economic analysis has been carried out to assess the feasibility of employing a new CF4 abatement and utilization process without HF effluent, where CaO was employed to convert produced HF into CaF2, a useful chemical. Moreover, the effect of employing multi‐bed series reactors compared with a single‐bed reactor on CaF2 production was analyzed using Aspen HYSYS® based on material and energy balances from process flow diagrams for three systems, a single‐bed reactor (S‐1), a two‐bed series reactor (S‐2), and a three‐bed series reactor (S‐3). From economic analysis to estimate annual operating cost savings for three systems, it was found that multi‐bed series reactors (S‐2 and S‐3) performed better than a single‐bed reactor (S‐1) due to equilibrium shift by Le Chatelier's principle leading to reduced operating temperatures to produce the same amount of CaF2 as S‐1. Consequently, annual cost savings of about 7 to 13% were obtained in S‐2 and S‐3 compared to S‐1 and this can serve as a useful guideline for the efficient system design. © 2017 Society of Chemical Industry and John Wiley & Sons, Ltd.

Optimal abatement technology adoption based upon learning-by-doing with spillover effect

We specify a general model of the dynamic abatement technology adoption process and show how the accumulated experience among them can alter the adoption timing. Learning-by-doing (LBD) effect is considered to describe the reduction of the costly price to the adoption. Moreover, spillovers effect which reflects how accumulated experience can be shared among different technologies, is integrated into the learning process. To ensure the specification convincing, some reasonable assumptions are considered such as one abatement technology must conduct its own experience in order to realize the spillover. Besides, to investigate how the abatement process is influenced by the technology allocation under the spillovers effect, an endogenous emission path is considered to necessitate a meaningful optimization problem. Finally, apart from obtaining some basic properties of the model, we implement an empirical study to verify the effectiveness of the model. Data from the iron industry in China is used to specify the process, which can highlight the spillovers effect among different technologies from a sector angle. In the results, we find that intrinsic mechanism in the model results in the interplay among abatement coefficient, spillover factor and the growing rate of the emission etc. Collaborative relationships between variables are discussed as well.

Modelling trade and climate change policy: a strategic framework for global environmental negotiators

In the past, failure of trade–climate talks might have created negative signs, but international trade actually induces more participation and helps to attain joint agreement. Carbon permit trading has a key role to play in the abatement process. Participation in global multilateral negotiations and a country's self-interest with respect to entering an abatement process depends upon either the scale of climate change damage or the punishment level that affects its economy. Thus, this study assumes N good cases for countries that have substantial emission levels. We analyse the change in utility function through a business-as-usual scenario for both group and individual country levels. The model designed in this study examines the data on emissions and gross domestic product (GDP) for selected developing and developed countries and the rest of the world. The data calibrations are similar to the previous studies. However, this study extends the model to a strategic level at which countries can choose coalition partners to undertake abatement for mutual benefits, considering the terms of trade. The results possess strong trade–environment policy options and help them to reach certain multilateral agreement.

Can Electrochemistry Make the Worlds Water Clean? – A Systematic and Comprehensive Overview

Water the generous gift of nature is sure to become scarce unless the ever growing population is enlightened enough in handling the increasing stress and to avoid the crisis due to the expanding demand on this precious commodity. Management of water and its resources by conservation and its judicious use help to preserve the available water. Even then, whether it is from surface or underground sources, it has become impossible to obtain good quality water for human consumption. Thus, the dwindling quantity and lessening quality of water require effective steps to be taken urgently for the sustenance of the living being of today and tomorrow. What this glass of water contains? worries one before he starts quenching his thirst. The extent of water contamination is so much and so varied that organic, inorganic and biological impurities are present in the water due to natural as well as induced reasons. The responsibility fell on the scientists and engineers to provide appropriate technologies help not only to remove the contaminants but also to treat at the user end. The conventional processes for pollution abatement are either physico-chemical or biological. The physicochemical methods aim at shifting the pollutants (land fill), concentrate the pollutant (adsorption), transfer the pollutant to another medium (air stripping) or cause secondary pollution (chemical precipitation leading to sludge). Biological techniques require narrow range of operating conditions. Electrochemistry provides technologies that have definite advantages than the above conventional methods. Electrochemical methods are versatile and offer not only clean but also cleaning technologies. The utility of electrochemical environmental techniques are expanding with the understanding and development of electrochemical engineering that led to design and development of novel electrodes and cell structures. The invention and large scale availability of improved polymeric and perfluorinated ionomers membranes have totally changed the purification and separation processes. Electrochemical analytical and sensing techniques are playing an important role in pollution control. Water quality up-gradation by electrochemical technique presents various alternatives, such as anodic, cathodic, direct and indirect methods to treat any type of contaminants in water and waste water. These methods, at the point of entry of pollutants into the environment, help not ony to remove the contaminant but also to recover and recycle useful chemicals. The electro-remediation of contaminated soil is, now, a proven and viable technology to prevent the pollution of water at the point of contamination itself. In this paper, the environmental applications of electrochemistry and some of the important and recent developments in the electrochemical methods of water and effluent treatment are reviewed. Electrochemical processes for decontamination of water from ions developed by CSIR-CECRI are also briefly described.

THE MODERN TECHNOLOGY OF IRON AND STEEL PRODUCTION AND POSSIBLE WAYS OF THEIR DEVELOPMENT

In the changing global market scenario for raw materials for the steel industry, a number of novel iron- and steelmaking process technologies are being developed to provide the steel companies with economically-sustainable alternatives for iron- and steel-making. In addition, the steel industry is also focusing on reduction of energy consumption as well as green-house gas (GHG) emissions to address the crucial subject of climate change. Climate change is presenting new risks to the highly energy- and carbon-intensive, iron and steel industry. The industry needs to focus on reduction of energy consumption as GHG emissions to address climate change. Development of alternate iron- and steelmaking process technologies can provide steel companies with economically-sustainable alternatives for steel production. For managing climate change risks, novel modeling tools have been developed by Hatch to quantify and qualify potential energy savings and CO2 abatement within the iron and steel industry. The tool developed for abatement of greenhouse gas carbon is called G-CAPTM (Green-House Gas Carbon Abatement Process) while that developed for improving energy effi ciency is called En-MAPTM (Energy Management Action Planning). Evaluation of existing operations have shown that most integrated plants have GHG and energy abatement opportunities; on the other hand, the best-in-class plants may not have a lot of low-risk abatement opportunities left, even at high CO2 price. In this context, it is important to assess these critical issues for the alternate iron- and steelmaking technologies that have been developed. This paper presents a comparative evaluation of energy-effi ciency and GHG emissions for some selected iron- and steelmaking technologies that are being considered for implementation. In this work, Hatch’s G-CAP™ and En-MAP™ tools that were developed with the main objective of quantifying and qualifying the potential energy savings and CO2 abatement within the iron and steel industry, were employed in the evaluation conducted.

Modeling analysis of energy requirement in aqueous ammonia based CO2 capture process

Aqueous ammonia is a promising alternative absorbent for CO2 capture from the flue gas of coal-fired power plants. The efficiency penalty of aqueous ammonia based CO2 capture process, however, is considerably heavy, resulting from the energy requirement for CO2 regeneration and NH3 abatement cycle. The paper focused on the whole process including CO2 absorption, CO2 regeneration, CO2 compression, NH3 abatement and NH3 recovery process, and analyzed the effects of operating parameters on the energy requirement of this process with a validated and reliable model. The sensible heat, stripping heat and desorption heat were calculated to gain insights into the regeneration process. The orthogonal analysis method was then adopted to find out the achievable minimum energy requirement for CO2 capture. The minimum energy requirement was identified as 2.89MJ/kg CO2 for CO2 regeneration process and 4.07MJ/kg CO2 for the whole process.

Prioritisation of odorants emitted from sewers using odour activity values

Volatile sulfur and volatile organic compound (VSC and VOC, respectively) emissions were measured over a 3.5 year period from 21 field monitoring sites across Australia to determine their potential contribution to sewer odours and support the evaluation of odour abatement processes used to treat sewer emissions. Measured VOC concentrations were generally less than 250 μg/m3, although some VOCs (toluene, trimethylbenzene and cymene) were present at higher concentrations. In general, sewer headspace VOCs are unlikely to be a significant contributor to sewer odours and VOC monitoring is only recommended for sites with a history of significant trade waste discharges or where odour character descriptors are typical of VOCs. A range of VSCs were identified, including hydrogen sulfide, ethyl mercaptan, methyl mercaptan, dimethyl sulfide, dimethyl disulfide, dimethyl trisulfide, carbon disulfide, and carbonyl sulfide. From a concentration perspective, the VSCs were dominated by hydrogen sulfide, followed by methyl mercaptan, and then a range of sulfides. Significant variations in VSC concentration and relative importance were observed between the cities and all identified VSCs were potentially odorous. An odorant prioritisation methodology to identify key and high priority odorants was developed and successfully demonstrated. While some high priority VOCs were identified, VSCs (hydrogen sulfide, methyl mercaptan, dimethyl sulfide, and dimethyl disulfide) were the dominant priority odorants. A wider range of VSCs should be assessed in addition to hydrogen sulfide to improve the evaluation of odour abatement processes.

A feasibility study on a novel stone dust looping process for abatement of ventilation air methane

This paper describes the development of a novel stone dust looping process that relates to the removal of ventilation air methane using stone dust. The working principle behind the stone dust looping process is incredibly simple which involves the catalytic oxidation of methane followed by carbonation and calcination reactions. In the current work, laboratory scale fluidized bed experiments and process simulations were conducted to evaluate the feasibility of the stone dust looping process. The experimental work concluded that oxidation of ventilation air methane in the stone dust looping process can be successfully achieved at temperatures between 500 and 650°C. The experimental results indicated that oxidation of methane was found to increase at higher temperatures while carbon dioxide capture efficiency showed a declining trend with increasing temperature. Furthermore, higher methane conversion and optimum (thermodynamic) carbon dioxide capture efficiency were observed for lower ventilation air methane flow rates and higher bed inventory. The concentration of methane in ventilation air methane and stone dust particle size did not have a significant effect on methane conversion or carbon dioxide capture. Also, comparison with synthetically prepared CuO and Fe2O3 catalysts has been made with CaO for VAM oxidation. CaO was found to be comparable to Fe2O3 and superior to CuO. From the process simulations, it was concluded that thermal energy generation in the carbonator was increased with higher methane and carbon dioxide concentrations. However, at the same time for higher methane and carbon dioxide concentrations, a greater CaO flux was required in the carbonator and hence a larger amount of goaf gas was required for the calcination reaction. The higher thermal energy generation in the carbonator was expected to improve the autothermicity of the stone dust looping process at concentrations of methane in the ventilation stream <0.2 vol.% (thermodynamic limit).

CIECIA: A new climate change integrated assessment model and its assessments of global carbon abatement schemes

From the perspective of global economic general equilibrium, this study developed a new climate change IAM named CIECIA. The economic core of this IAM is a multi-country-sector general equilibrium model. The endogenous technology progress mode is introduced into CIECIA. Based on this model, three assessment principles of the global cooperating abatement scheme are proposed, including effectiveness, feasibility, and fairness. This study simulated and analyzed six types of primary global cooperating abatement schemes. The simulated results indicate that all of the selected schemes can satisfy the climate mitigation targets by 2100. Thus, they are all effective schemes. However, the schemes have quite different feasibilities and fairness. The Stern Scheme benefits the developed countries, but is unfair to the developing countries. The Nordhaus Scheme promotes the developments of the developing countries. However, it leads to negative impacts on the interests of the developed countries. The principle of convergence on accumulated carbon emissions per capita and the principle of convergence on carbon emissions per capita benefit the economic developments of the middle and low developing countries most. However, these two types of schemes cause tremendous losses to the main economic entities in the world including China. The Pareto Improvement Scheme, which was developed from the Global Economic Growth Scheme, balances the fairness and feasibility in the carbon abatement process and realizes the Pareto improvement of accumulated utilities in all the participating countries. Thus, the Pareto Improvement Scheme is the most reasonable global cooperating carbon abatement scheme.

The modern technology of iron and steel production and possible ways of their development

In the changing global market scenario for raw materials for the steel industry, a number of novel ironand steelmaking process technologies are being developed to provide the steel companies with economically-sustainable alternatives for ironand steel-making. In addition, the steel industry is also focusing on reduction of energy consumption as well as green-house gas (GHG) emissions to address the crucial subject of climate change. Climate change is presenting new risks to the highly energyand carbon-intensive, iron and steel industry. The industry needs to focus on reduction of energy consumption as GHG emissions to address climate change. Development of alternate ironand steelmaking process technologies can provide steel companies with economically-sustainable alternatives for steel production. For managing climate change risks, novel modeling tools have been developed by Hatch to quantify and qualify potential energy savings and CO2 abatement within the iron and steel industry. The tool developed for abatement of greenhouse gas carbon is called G-CAPTM (Green-House Gas Carbon Abatement Process) while that developed for improving energy efficiency is called En-MAPTM (Energy Management Action Planning). Evaluation of existing operations have shown that most integrated plants have GHG and energy abatement opportunities; on the other hand, the best-in-class plants may not have a lot of low-risk abatement opportunities left, even at high CO2 price. In this context, it is important to assess these critical issues for the alternate ironand steelmaking technologies that have been developed. This paper presents a comparative evaluation of energy-efficiency and GHG emissions for some selected ironand steelmaking technologies that are being considered for implementation. In this work, Hatch’s G-CAP™ and En-MAP™ tools that were developed with the main objective of quantifying and qualifying the potential energy savings and CO2 abatement within the iron and steel industry, were employed in the evaluation conducted.

“Egg of Columbus”: Single-step complete removal of chloride impurities from ionic liquids by AgCl deposition on silver electrode

Chloride impurities in ionic liquids (ILs), which can be present even in huge amounts depending on the IL synthetic route, are particularly critical for electrochemical processes; thus, their abatement is often mandatory. However, while their analytical quantification has been the subject of many studies involving a variety of techniques, the so far available processes for their abatement are still unsatisfactory, having low efficiency, and/or involving multiple steps, and/or being far from mild and easily scalable. In this context, like an “egg of Columbus”, a quite simple and safe process for chloride abatement in ILs is proposed, practically coinciding with the electrolytic preparation of a Ag|AgCl electrode. It proceeds in a single step, at room temperature, at very low potentials, with nearly ideal current efficiencies, and with negligible side effects on the electrolyzed IL. The chloride impurities are quantitatively captured and accumulated on the silver wire and eliminated by simply removing the resulting Ag|AgCl electrode from the solution, with no need of subsequent treatments.

Modeling of the NH3–CO2–H2O vapor–liquid equilibria behavior with species-group Pitzer activity coefficient model

The vapor–liquid equilibria (VLE) model of the NH3–CO2–H2O system is crucial to the ammonia-based CO2 capture processes simulation and the proposition of innovation processes. Though traditional VLE models could describe the behavior of this system, they are always suffering too many regressed parameters and, more serious, the number of these parameters increases with the number of real species in the solution raised to the power of higher than 2. To conquer this problem, an upgraded thermodynamic model of the NH3–CO2–H2O system with the species-group Pizter activity coefficient model has been developed on the basis of the original model proposed by Krop (1999). Comparing with the commonly used activity coefficient models such as E-NRTL, extended UNIQUAC and original Pitzer model, the species-group Pizter activity coefficient model relates the parameters to the groups of species instead of real species in the solution, leading to significantly reducing the number of regressed parameters and simplifying the calculation. However, in the original model, the precipitation was not considered, which makes the validity of the model questionable, and the calculation of enthalpy, great importance for CO2 emission abatement processes, was also not taken into account. Therefore, in this work, the solid–liquid equilibria (SLE) of the NH4HCO3–H2O system were employed in the upgraded model to represent the precipitation and a new set of parameters were refitted against VLE data with genetic algorithm. The results indicate that this simplified thermodynamic model could satisfactorily describe the thermodynamic behavior of the NH3–CO2–H2O system.

Competing uses for China's straw: the economic and carbon abatement potential of biochar

AbstractChina is under pressure to improve its agricultural productivity to keep up with the demands of a growing population with increasingly resource‐intensive diets. This productivity improvement must occur against a backdrop of carbon intensity reduction targets, and a highly fragmented, nutrient‐inefficient farming system. Moreover, the Chinese government increasingly recognizes the need to rationalize the management of the 800 million tonnes of agricultural crop straw that China produces each year, up to 40% of which is burned in‐field as a waste. Biochar produced from these residues and applied to land could contribute to China's agricultural productivity, resource use efficiency and carbon reduction goals. However competing uses for China's straw residues are rapidly emerging, particularly from bioenergy generation. Therefore it is important to understand the relative economic viability and carbon abatement potential of directing agricultural residues to biochar rather than bioenergy. Using cost‐benefit analysis (CBA) and life‐cycle analysis (LCA), this paper therefore compares the economic viability and carbon abatement potential of biochar production via pyrolysis, with that of bioenergy production via briquetting and gasification. Straw reincorporation and in‐field straw burning are used as baseline scenarios. We find that briquetting straw for heat energy is the most cost‐effective carbon abatement technology, requiring a subsidy of $7 MgCO2e−1 abated. However China's current bioelectricity subsidy scheme makes gasification (NPV $12.6 million) more financially attractive for investors than both briquetting (NPV $7.34 million), and pyrolysis ($−1.84 million). The direct carbon abatement potential of pyrolysis (1.06 MgCO2e per odt straw) is also lower than that of briquetting (1.35 MgCO2e per odt straw) and gasification (1.16 MgCO2e per odt straw). However indirect carbon abatement processes arising from biochar application could significantly improve the carbon abatement potential of the pyrolysis scenario. Likewise, increasing the agronomic value of biochar is essential for the pyrolysis scenario to compete as an economically viable, cost‐effective mitigation technology.

Multi-objective optimization for the design and synthesis of utility systems with emission abatement technology concerns

The sustainable design configuration of utility systems incorporating pollutant emission abatement technologies has an important influence on economic cost, pollutant emission, and energy consumption of the process industry. In this paper, four typical cogeneration systems that address different emission reduction technologies are proposed as candidate structures for utility system design. The proposed systems are a gas boiler-based cogeneration system firing clean natural gas, circulating fluidized bed boiler-based cogeneration system incorporating SO2 abatement during combustion, pulverized coal boiler-based cogeneration system encompassing desulfurization and denitration after combustion, and gas–steam combined cogeneration system firing clean natural gas. The equipment performance, energy consumption, material consumption, pollutant emission, and investment and operation cost models of these cogeneration systems, as well as the corresponding emission abatement processes, are established. A multi-objective mixed integer nonlinear programming (MOMINLP) model is formulated to determine the equipment type (or cogeneration system and emission abatement technology), equipment number, equipment design capacity, and equipment operation load while simultaneously combining the multiple objectives of minimization of economic cost, minimization of environmental effect, and maximization of exergy efficiency. The original MOMINLP model is converted into a multiple objective mixed integer linear programming (MOMILP) model through linear approximation, unit size discretization, and relaxation. The augmented ε-constraint method is applied to identify the set of Pareto optimal solutions with respect to the aforementioned objective functions. An example of industrial utility system design optimization was presented. In addition, the best combination of cogeneration system for utility system structure under different objective was introduced. The sensitivity of the solutions to the primary energy source price and power to heat ratio was conducted.

Low-Pressure Plasma Reactor with a Cylindrical Electrode for Eco-friendly Processing in the Semiconductor Industry

Thin film deposition processes emit large amounts of NF3 and by-product particles, which are of great concerns in the semiconductor industry, from the environmental and economic points of view. With an objective to overcome these concerns, plasmas are generated from a cylindrical reactor placed before a vacuum pump. The discharge stability is evaluated by monitoring the changes in the plasma images with the pressure. By using a particle sampler and a particle trap, the size and quantity of the by-product particles are compared during plasma-on and plasma-off. The effects of adding O2 and H2O to the by-products of the NF3 abatement process are investigated by analyzing the spectra obtained with a Fourier transform infrared spectroscopy. Further, the H2O flow rate is optimized for the highest destruction and removal efficiency of NF3. Finally, the applicability of our device to the after-treatment equipment is discussed.

Ornamental plants as sinks and bioindicators

Mitigation of urban air pollution is a big challenge, especially for the metropolitan cities of the world. In an Indian metropolis like Delhi, even after the implementation of several control policies, no such remarkable change has been observed in its air quality. Globally, afforestation or greenbelt development is an effective and well-recognized pollution abatement process. The aim of our present study was to examine the biochemical response of some naturalized ornamental plant species, viz. Dracaena deremensis, Tagetes erecta, Rosa indica and Dianthus caryophyllus. During experimental study, plants were kept at selected sites which were categorized in terms of traffic density (emission source) and vegetative pattern during winter months for 120 days. Four biochemical parameters, viz. total chlorophyll, ascorbic acid, pH, relative water contents along with Air Pollution Tolerance Indices were determined from foliar samples at each selected site. D. deremensis and T. erecta were classified under tolerant while R. indica and D. caryophyllus were marked as in sensitive category. Based on the sensitivity of selected plant species, it has been recommended that D. deremensis and T. erecta may be used as sinks for the abatement of air pollution at highly polluted sites whereas R. indica and D. caryophyllus can be used as bioindicators.