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Engine manufacturers worldwide are forced to reduce diesel engine emissions like PM, CO, NOx, etc. Of late post combustion exhaust after-treatment devices viz. SCR, Selective Catalytic Converter, D...

Given the dominant share of coal in China’s energy-generation mix and the fact that >50% of the power plants in the country are currently

The importance of Coal in generation of electricity is well established. But, during the combustion of coal for generation of electricity, oxides of nitrogen (NOx) are also released. These oxides of nitrogen are pollutants which have an adverse effect on both the human life as well as the environment. Due to the increased pollution level from Coal Fired Power Plants, Ministry of Environment & Forests (MOE&F) on Dec 2015, announced stringent standards for coal based thermal power plants under the Environment Protection Act of 1986. Though various NOx control systems have been installed and functioning properly worldwide, but their provenness in the Indian scenario is yet to be established. As the coal in which the Indian power plants operates have a very different characteristics than the coal used abroad for power plants. This paper aims to address and explore the various methods and challenges in reducing the NOx emissions from Coal Fired Power Plants while firing Indigenous coal.

There is a wide range of resources for CO2 emissions. The net amount of CO2 emissions in the cement industry due to the consumption of fossil fuels and the chemical processes of cement prod...

To reach the short-term targets of the carbon dioxide limit, measures such as carbon capture and storage are necessary. The objective of this paper is to assess some low-temperature post-combustion...

This paper gives an overview of all the most significant results obtained during the CO2 capture pilot plants operation with Shell CANSOLV’s amine-based solvent DC-103. The pilot plant campaign at a full-scale waste to energy (WtE) plant in Oslo, Norway achieved its primary purpose of demonstrating low amine related emission levels during a test campaign of many months during 2019. This assures that the planned full-scale CO2 capture plant will meet the expected emissions specifications. It also allowed to gather important data on absorbent degradation in actual operation on WtE plant flue gas and confirm other performance parameters of the technology such as capture efficiency, energy requirements and product (CO2) purity.

The energy in general and electricity, in particular, plays a key role in the development of any nation. In India, about 60% of electricity demand is fulfilled by coal-based power plants. Increasing CO2 concentration in the environment is a global problem for which coal-based power plants are the main contributors. The present study is focused on the energy and exergy-based thermodynamic analysis of a 500 MWe Subcritical thermal power plant with Monoethanolamine (MEA) based post-combustion CO2 capture. The study is further carried out by using solar energy for reducing the energy penalty against MEA regeneration. A computer software program “Cycle-Tempo” is used for simulating the plants. The study reveals that use of solar energy for MEA regeneration instead of using steam increases the plant energy and exergy efficiencies about 2.4% and 5.4% points, respectively. The CO2 avoided by the plant is 0.71 kg/kWh. The total solar collector area required is about 347.6 acres.

This work presents a mathematical modeling framework for the simulation and optimization of pressure/vacuum swing adsorption (P/VSA) processes for post-combustion CO 2 capture. A single-stage P/VSA process for CO 2 capture from dry flue gas is considered using new zeolite 13X-based adsorbents resulting from perturbation on the 13X zeolite isotherm. A two-bed six-step P/VSA cycle configuration with light product pressurization is employed in systematic simulation and optimization studies. First a zeolite 13X, the current benchmark commercial adsorbent for CO 2 capture, is considered. Accordingly, the model is used to study and evaluate new zeolite 13X-based adsorbents for more efficient CO 2 capture. The results from systematic comparative simulation studies demonstrate that a modified zeolite 13X-based adsorbent appears to have better process performance compared with the original zeolite 13X. Furthermore, process optimization studies employing the above potential adsorbents are performed to minimize energy consumption for specified minimum requirements in CO 2 purity and recovery. The optimization results indicate that the minimum target of 95% in CO 2 purity and 90% in CO 2 recovery is easily met for the P/VSA process under consideration for both potential adsorbents under different operating conditions resulting in different energy requirements and CO 2 productivity.

The aim of the work is to carry out an economic assessment of the effect of various structures of multi-tiered oxygen lances and methods for flushing the converter bath with the afterburning of waste gases on the efficiency of the production of iron-carbon semi-products in a modern metallurgical plant. The study was conducted for the process of steel smelting in converters of combined blowing with supply of oxygen from above and neutral gas through the bottom in the conditions of using conventional and multi-tiered oxygen tuyeres. Studies on the afterburning of converter gas in the converter cavity showed that, in proportion to the increase in the proportion of CO2 in the exhaust gases, the costs of steel production are reduced. Compared with the use of tuyeres of classical construction, they amount to 3.23 US dollars / ton of steel for double-circuit, 6.81 US dollars / ton of steel for bunk, and 11.61 US dollars / ton of steel for three-tier. It was determined that when using the classic design of the upper oxygen tuyere, the lower heat of combustion of the converter gas is 10 MJ / m3. In comparison with the classical design, the two-tier, double-circuit and three-tier tuyeres ensure a reduction in the lower heat of combustion of the converter gas by 8,5; 4.4 and 27.1% (rel.), Respectively. On the basis of the data obtained, it is possible to draw a conclusion about the effectiveness of using the technology of combined blowing of the converter bath with the afterburning of exhaust gases in the converter cavity.

The energy consumption associated with absorbent regeneration remains the most critical challenge for the industrial implementation of chemisorption based CO 2 capture processes. Aimed at reducing the energy consumption, this paper proposes a promising process modification of the ammonia (NH 3 ) based CO 2 capture process that involves an advanced flash stripper with a cold rich split. We investigated the techno-economic performance of the advanced NH 3 process integrated with a 650 MW coal-fired power plant, and evaluated it technical and energy performance using a rigorous, rate-based model in Aspen Plus. A sensitivity study was also performed to optimise the modelling parameters, i.e. the stripper pressure and the absorbent NH 3 concentration, and minimize the regeneration duty. A very competitive regeneration duty of 1.86 MJ/kg CO 2 was achieved for an optimised stripper pressure of 12 bar and an NH 3 concentration of 10.2 wt%, with a total equivalent work of 0.164 MW h/t CO 2 for absorbent pumping, NH 3 regeneration and CO 2 compression. We also used a validated economic model to estimate the capital investment of the advanced NH 3 process and its corresponding economic performance. With its significant reduction in energy consumption, the proposed process was economically competitive with CO 2 avoided cost was as low as US$40.7/t CO 2 . This was 34% and 44% less than the reference NH 3 and monoethanolamine (MEA) processes, respectively. The advanced NH 3 based flash stripper also had technical and economic advantages over other amine absorbents, such as MEA and piperazine (PZ), as well as other advanced stripper modifications, such as inter-heating process, revealing its process viability in commercial application.

Gas-fired industrial furnaces are used for heat-treatment of semi-finished steel products. The required energy is provided by gas-fired burners, which are supplied by fuel and air. The combustion is often realized fuel rich to avoid scale formation at the product surface. Thus, the flue gas contains unburnt products, which are oxidized in a post combustion chamber by adding fresh air. The control of the volume flow of air to the post combustion chamber is a crucial task because the flue gas leaving the furnace must not contain unburnt products. For this control task, a two-degrees-of-freedom control strategy based on differential flatness in combination with a MIMO-PI controller is proposed. The basis for the control design is a first-principles mathematical model of the air supply circuit and the combustion of flammable products. The model is validated by means of measurement data from a real plant.

IHI has been developing Post Combustion Capture (PCC) technology using a chemical absorption process which is applied to coal-fired power plants. To reduce the costs of CO 2 capture, we have been investigating advanced amine solvents, packings, and process. The 2 nd IHI packing and new process were evaluated at a 20 ton-CO 2 /d pilot plant. The absorption performance of the 2 nd IHI packing was 1.8 times higher than a conventional packing with almost the same pressure loss per unit height. As a result of process performance tests, the regeneration energy of new IHI process achieved less than 2.4 GJ/t-CO 2 exluding the radiation heat.

A new synthetic polyamine was found as a suitable compound for amine-impregnated solid sorbent through screening of amine compounds with the aid of density functional theory calculations. CO 2 capture performance of the sorbent was evaluated on a lab-scale CO 2 capture system. The solid sorbent was excellently regenerable even at low temperature condition. Then, Bench-scale demonstration will be started on current project, using the sorbent developed by Research Institute of Innovative Technology for the Earth (RITE) and moving bed system of Kawasaki Heavy Industries, Ltd (KHI).

IHI, with technical support from CSIRO, designed and constructed the “PICA pilot plant”, for the continued development of an advanced PCC process, which will enable a reduction in the CO2 capture absorbent regeneration energy by 40% compared to the conventional MEA based process. The project team installed the pilot plant at the AGL Loy Yang power plant in Australia. The pilot plant has been commissioned and tested in a conventional MEA based process configuration and has commenced a 5,000 hour operating campaign using the IHI absorbent and the IHI optimized process configuration, and had achieved 1,800 hours of operationby mid September, 2016. The designed CO2 capture ratio of 90% has been achieved and stable plant operation has been confirmed. Continuous analysis will be kept for confirming the performance and robustness of the system.

The performance of a mono-ethanolamine-based post-combustion CO2 capture plant was assessed experimentally using a dedicated pilot plant located at a coal-fired power station in China. The 1000-h pilot campaign enabled the assessment of the flue gas pre-treatment process, the conduct of a parametric study for optimization of the thermal energy requirement, determination of degradation products in the absorption liquid, and measurement of main process emissions. These results are compared with results in reports on other pilot plant operations based on mono-ethanolamine. © 2016 Society of Chemical Industry and John Wiley & Sons, Ltd.

Siloxanes present in small concentrations in biogas interfere with the operation of biogas-to-energy facilities. During biogas combustion, siloxanes form white deposits on engine components (engine heads, spark plugs, valves) in crystals or amorphous forms depending on the temperature. The purpose of this study was to evaluate the economic feasibility of biogas-to-energy systems for managing the operational challenges due to siloxanes in biogas. The facility maintenance cost data were compiled by a survey of biogas-to-energy facilities in the United States. Economic analyses were performed to compare the operational costs due to increased maintenance for removing the white deposits forming on the engine components and the installation of a pretreatment system (carbon adsorption) to remove siloxanes prior to combustion. Numerical analyses showed that for the facilities with operating capacities less than 1300 m3/h (750 scfm), the costs for installation and operation of the carbon adsorption system exceeded the maintenance costs for removal of deposits from the engine components. The maintenance costs correlated well with the reported maintenance needs which were between 120 and 800 man hours per year. On the basis of siloxane removal costs alone, it is not economically feasible to install a carbon adsorption system for siloxane removal prior to combustion for small facilities processing less than 1300 m3/h (750 scfm) of biogas. However, using a process for siloxane removal prior to gas engines (e.g., carbon adsorption) would be improve the overall performance of the gas engines and reduce maintenance need at all facilities.

This paper presented a comparative study of monoethanolamine (MEA) and diethanolamine (DEA) for post-combustion CO2 capture (PCC) process with different process configurations to study the interaction effect between solvent and process. The steady state process model of the conventional MEA-based PCC process was developed in Pro/II® and was validated with the experimental data. Then ten different process configurations were simulated for both MEA and DEA. Their performances in energy consumption were compared in terms of reboiler duty and total equivalent work. The results show that DEA generally has better thermal performances than MEA for all these ten process configurations. Seven process configurations provide 0.38%–4.61% total energy saving compared with the conventional PCC process for MEA, and other two configurations are not favourable. For DEA, except one configuration, other process configurations have 0.27%–4.50% total energy saving. This work also analyzed the sensitivities of three key parameters (amine concentration, stripper pressure and lean solvent loading) in conventional process and five process modifications to show optimization strategy.

In this paper, optimization of a post combustion carbon capture process based on two different objective functions of energy and utility requirements and associated costs is presented. CO2 residual mole fraction of the regenerated solution, solution circulation rates and lean solution temperature were selected as three most important variables of the process for optimization. One at a time method is adopted for optimization of the process variables. The results show that for a post combustion carbon capture process using monoethanolamine (MEA), lowest costs of the process are associated with the highest CO2 residual mole fraction of regenerated solution, lowest solution circulation rate and highest lean solution temperature. Based on the results of this research, having a general view of energy and utility requirements of the process leads to finding the lowest possible process costs. However, if a component oriented view is adopted for energy requirements, the worst possible choices of operational parameters are likely to be made.

Thiourea was selected as representative of combined S- and N-inhibitors and injected after the post-combustion zone of two full-scale municipal solid waste incinerators (MSWIs) using a dedicated feeder. Firstly, the operating conditions were scrutinised by monitoring the concentrations of SO2, NH3 and HCl in the clean flue gas. The suppression experiment showed that in MSWI A thiourea could reduce the total I-TEQ value in flue gas by 73.4% from 1.41 ng I-TEQ/Nm3 to 0.37 I-TEQ/Nm3, those in fly ash by 87.1% from 14.3 ng I-TEQ/g to 1.84 I-TEQ/g and the total dioxins emission factor by 87.0 wt.%, with a (S + N)/Cl molar ratio of 9.4. The suppression efficiencies of PCDD/Fs in flue gas and fly ash in MSWI B could be up to 69.2% and 83.0% when the (S + N)/Cl molar ratio attained 7.51. Furthermore, the congener distributions of dioxins were also analysed in the flue gas and fly ash, before and after addition of thiourea, to find cues to some suppression mechanism. In addition, the filtered fly ash was explored by the Scanning Electron Microscope (SEM) and Energy Dispersive Spectrometer (EDS) analysis of fly ash. These results suggest that poisoning the metal catalyst and blocking the chlorination are most probably responsible for suppression.

There are currently no studies in the literature on the use of natural waste marble powder (WMP) resources as inexpensive sorbents for looping cycle CO2 capture. The high volume of marble production is associated with considerable amounts of WMP generated as byproduct during cutting and polishing procedures, which negatively impacts the surrounding environment. The main goal and innovative idea addressed in this study consists of investigating if solid wastes WMP from marble producer sources can be used as possible inexpensive and effective solid materials to be used as precursors of CaO-based sorbents in Ca-looping cycle CO2 post-combustion capture process. The cyclic carbonation–calcination reactions were experimentally studied in a laboratory-scale fixed-bed reactor unit for 10 and 20 cycles. The innovative and interesting results obtained show that Portuguese WMP represents a category of promising natural inexpensive solid sorbents to be used as effective CaO-based sorbents for looping cycle CO2 post-...

Some features of heating and melting iron-rich pellets (IRP) by the method of charging the pellets through the axial ducts of electrodes are considered. When using this system of supplying iron ore raw materials through the holes in the electrodes, loose pellets fall into the impact zone of the electric arcs on the melt that ensures a high speed of their fusion. At the same time the technical-and-economic indices of the electrosmelting in the electric arc furnace (EAF) are improved. The use of the fuel-oxygen burners allow optimizing the IRP melting process improving the slagging conditions, heating, metal decarburization with post-combustion of final burning gases (CO, H2, etc.) in the arc furnace.

The more and more restrictive environment requirements in the field of pollutant emissions of co-generative plants are imposing researches related to the more efficient work of those related to the post combustion facility. The paper presents the results of a post combustion burner achieved on a test bench, when it idling operates on natural gas mixed with air or with burned gases of a gas turbine. The modeling of the measured emissions, led to NOx concentrations in ambient air that are below the limits imposed by the in force regulations related to air quality and are correlated to the real time measured data.

The market of solar-assisted post-combustion CO2 capture (SPCC) is emerging globally in recent years. It is considered as a promising technology to apply the ammonia as the absorbent to implement the SPCC technology in view of its low regeneration temperature and low regeneration heat duty. However, few literatures indicate which type of solar thermal collectors (STCs) involved in the ammonia-based SPCC power plant is more applicable. Therefore, in this paper, the maximum theoretical potential price of STCs which make the value of the levelized costs of electricity (LCOE) and the cost of CO2 removed (COR) lower than that of the reference post-combustion CO2 capture (PCC) power plant is estimated. The potential of ammonia-based SPCC technology in the selected locations is also estimated, based on the detailed solar radiation resource assessment (i.e. DNI, sunshine time) and the STCs performance. It would be more attractive to adopt the vacuum tube (VT) as the STC involved into the ammonia-based PCC power plant to capture CO2 than parabolic trough collector (PTC). In order to achieve lower LCOE and COR than that of the reference PCC system, the price of the vacuum tube (VT) has to be reduced to 131.02 $/m2, 91.76 $/m2 and 57.10 $/m2 for the location of M1(Lhasa), M2(Tianjin) and M3(Xi’an), respectively. And the price of the parabolic trough collector (PTC) has to be reduced to 139.09 $/m2, 89.83 $/m2 and 50.84 $/m2, respectively.

Post-combustion capture of CO 2 from the flue gas of power plants by calcium looping, in which lime is used to capture CO 2 , is currently a promising technology. The decay in CO 2 uptake capacity of natural limestone is an intrinsic disadvantage of this technology, and the design of more stable sorbents has become an important goal. Techno-economic calculations that examine calcium looping must take into account this decay in capacity, and this has to date been accomplished using a formula for the population distribution of particles in the cycling system. However, the formula has some limitations that make it less suited to very stable sorbents, making it difficult to incorporate newer materials in such calculations. We developed a more general formula for the population distribution of solid particles in processes involving recirculations, and compared it with the widely used equation in the calculation of several process metrics. Particular consideration was given to conditions relevant to enhanced or tailored sorbents, for which our modified formula was well suited. In addition, the impacts of calcium looping process configuration on this generalized population distribution of solid particles were studied from mathematical and operational perspectives.

Mercury emissions from coal-fired power plants pose impact on human health. The emissions will be regulated in the near future. Mercury speciation in flue gas has an important effect on the efficiency of mercury emission control devices. This study focuses on the role of fly ash on the oxidation of Hg° in bench-scale simulated flue gas environment and in laboratory-scale coal combustion flue gas environment. The effects of flue gas matrices, temperature, fly ash mineralogy and morphology on the oxidation of Hg° are studied. Conclusions are drawn based on the testing results: • Mercury chemistry is very complex in flue gas. • The presence of fly ash is critical for heterogeneous Hg° oxidation. • The flue gas components, including NO2, HC1, NO and SO2, have strong effects on the potential of whole fly ashes to oxidize Hg°. • Fly ash specific surface area appears to have a determining effect on Hg° heterogeneous oxidation.

Summary Masdar has initiated the Abu Dhabi Carbon-Capture and -Storage Project, with the objective to develop a carbon-capture network in Abu Dhabi capable of creating large reductions of carbon dioxide (CO2) emissions and with the capacity to increase oil recovery by use of CO2 for enhanced oil recovery (EOR). Because Siemens (henceforth referred to as the Technology Owner) has developed, tested, and piloted a proprietary post-combustion CO2-capture technology (PostCapTM) for the removal of CO2 from the flue gas of coal- and gas-fired power plants suitable for the project, both parties decided to cooperate in executing a front-end engineering and design (FEED) study. The technology is based on an aqueous amino-acid-salt solution. The Technology Owner and Masdar have completed a FEED study for capturing 1,800,000 tons of CO2 annually from a natural-gas-fired power plant in Abu Dhabi by application of the PostCapTM technology. Various opportunities and challenges were encountered during the design of the retrofit capture plant. Challenges were often specific to the region, including local climate, water availability, and flue-gas quality. Design and optimization of the plant were influenced by local energy and labor prices. Further opportunities included integration with the power plant and with a local industrial facility. The power plant had to supply the capture plant with steam and power without reducing the original electricity-production capacity. To accomplish this, several heat- and power-integration concepts were evaluated with respect to their feasibility, including the application of a backpressure steam turbine and the retrofit of a simple-cycle gas turbine to combined-cycle gas turbine. Various cooling options were considered in view of climate and resource challenges. Cooling water had to be extracted from a reflux stream produced by an adjacent industrial facility. Drawing on the results of the FEED study, this paper presents the manner in which PostCapTM technology can be applied for capturing CO2 at a power plant in Abu Dhabi for the purpose of EOR, while satisfying specific local needs, and the way utility supply and power plant integration can be facilitated.

Currently, post-combustion carbon capture (PCC) is the only industrial CO2 capture technology that is already demonstrated at full commercial scale in the TMC Mongstad in Norway (300,000 tonnes per year CO2 captured) and BD3 SaskPower in Canada (1 million tonnes per year CO2 captured). This paper presents a comprehensive review of the most recent information available on all aspects of the PCC processes. It provides designers and operators of amine solvent-based CO2 capture plants with an in-depth understanding of the most up-to-date fundamental chemistry and physics of the CO2 absorption technologies using amine-based reactive solvents. Topics covered include chemical analysis, reaction kinetics, CO2 solubility, and innovative configurations of absorption and stripping columns as well as information on technology applications. The paper also covers in detail the post build operational issues of corrosion prevention and control, solvent management, solvent stability, solvent recycling and reclaiming, intelligent monitoring and plant control including process automation. In addition, the review discusses the most up-to-date insights related to the theoretical basis of plant operation in terms of thermodynamics, transport phenomena, chemical reaction kinetics/engineering, interfacial phenomena, and materials. The insights will assist engineers, scientists, and decision makers working in academia, industry and government, to gain a better appreciation of the post combustion carbon capture technology.

As a part of the strategic research program “Advanced technologies for energy generation: Development of a technology for highly efficient zero-emission coal-fired power units integrated with CO2 capture”, a mobile CO2 absorption pilot plant was erected. The main purpose of the pilot plant was to demonstrate the post-combustion technology in conjunction with a coal-fired power plant. The pilot plant captured CO2 by chemical absorption in amine-based solvents, which was considered to be the best adapted technology to the requirements of coal-fired power plants and suitable for retrofitting to existing units. The pilot plant captured up to 1000 kg/day of CO2 from the power plant’s flue gases with CO2 recovery exceeding 90 %. The flexible process flowsheet of the pilot plant offered high potential for the validation of various improvements, which were designed to reduce the process energy demand and to increase the CO2 recovery. This paper summarizes the initial operation experience at the TAURON Łaziska Power Plant in Poland. Selected first results obtained are presented and discussed. The initial campaigns utilized 20 and 30 wt% monoethanolamine (MEA) solutions recognized as baseline solvents that were suitable for comparative purposes. The initial campaigns at the pilot plant successfully demonstrated reliable operation and promising results.

In recent decades, the accelerating economic and social developments have led to exponentially increasing emissions of carbon dioxide (CO2) into the atmosphere. As a result, much research efforts have been directed toward more effective measures for the carbon capture and storage (CCS). In this review, we first briefly described the general background on the various techniques available for the abatement of CO2 emissions worldwide. Then, we provided an in-depth discussion regarding the two comparable control technologies, i.e., the amine- vs. ammonia-based capture approaches; ammonia has lower energy costs than monoethanolamine (MEA). The applicability of each method was described further with an emphasis on their advantages and disadvantages. We also briefly discussed the available options for post-absorption processing such as recovery of absorbed CO2, compression, and storage. Many immobilized amines as adsorbents can only be regenerated a few times or are a ‘once-through process’. This may deplete the global supply of those materials if CCS is scaled up in excess of Mton CO2 captured per year. Ideally, the captured CO2 should be isolated from the atmosphere indefinitely and/or photochemically reduced (either biologically or industrially). Finally, we explored future challenges in this field of study to envision and suggest more optimized solutions.

An important process consideration in ammonia-based, post-combustion CO2 capture is the volatility of ammonia. Consequently, there is a need to adopt control measures to minimize the emission (the slip) of ammonia from such processes. This work evaluates techno-economic aspects of methods to reduce the ammonia slip. The emission of ammonia is required to be below 10 ppm while the ammonia slip from the absorber in an ammonia-based process may exceed 10%. The ammonia control methods that are evaluated in this work are staged absorption, ammonia abatement cycle, chilled absorption and acid wash. The control methods are also evaluated with respect to local conditions, such as cooling water temperature and flue gas CO2 concentration. Rate- and equilibrium-based thermodynamic modelling forms the basis for the evaluation process. A simplified economic estimation method is used to evaluate the utility cost of ammonia control designs under different operating conditions. The economic estimation shows that for the best case conditions the utility cost are as low as 1.5(sic)/tCO(2). However, the cost of the ammonia control may be more than tenfold when the available cooling water temperature is increased (>5 degrees) or when the flue gas CO2 concentration is decreased (

Amine scrubbing, a mature post-combustion carbon capture and storage (CCS) technology, could increase ambient concentrations of fine particulate matter (PM2.5) due to its ammonia emissions. To capture 2.0 Gt CO2/year, for example, it could emit 32 Gg NH3/year in the United States given current design targets or 15 times higher (480 Gg NH3/year) at rates typical of current pilot plants. Employing a chemical transport model, we found that the latter emission rate would cause an increase of 2.0 μg PM2.5/m(3) in nonattainment areas during wintertime, which would be troublesome for PM2.5-burdened areas, and much lower increases during other seasons. Wintertime PM2.5 increases in nonattainment areas were fairly linear at a rate of 3.4 μg PM2.5/m(3) per 1 Tg NH3, allowing these results to be applied to other CCS emissions scenarios. The PM2.5 impacts are modestly uncertain (±20%) depending on future emissions of SO2, NOx, and NH3. The public health costs of CCS NH3 emissions were valued at $31-68 per tonne CO2 captured, comparable to the social cost of carbon itself. Because the costs of solvent loss to CCS operators are lower than the social costs of CCS ammonia, there is a regulatory interest to limit ammonia emissions from CCS.

One option to mitigate the adverse effect of power plant output loss from adding a CO 2 capture plant is to operate it in flexible modes in which the capture level and/or regeneration rate are dynamically varied in response to varying electricity market demand and price. This can help the plant meet peak electricity demand and improve its overall profit. However, the benefit is offset by higher capital costs and/or CO 2 emission penalty. Various modes of flexible operation including capture level reduction and solvent storage have been optimized for a given post-combustion capture system with typical daily electrical energy price patterns and the results are compared with those from a fixed point operation. Effects of varying storage capacities and energy price patterns have also been evaluated. Simultaneous use of the two flexible modes is also optimized and the result showed significantly higher cost savings compared to the individual uses.

In this study, five absorption/stripping process configurations, including a conventional process, split flow with overhead exchanger, simple vapor recompression, and two new configurations-split flow with vapor recompression (SFVR), and improved split flow with vapor recompression (ISFVR) using 30 wt% aqueous monoethanolamine (MEA) for CO 2 capture from a 300 MW power plant were simulated and compared, usingthe ProMax3.2 program. In the SFVR and ISFVR, the heat from the stripper overhead vapor and CO 2 compression system were recovered to the stripping column in order to reduce the reboiler duty and overall energy consumption. Sensitivity analyses were carried out to evaluate the effects of key parameters (e.g. lean CO 2 loading and feed fraction) with regards to energy consumption. The simulation results showed that the innovative configurations SFVR and ISFVR could fully utilize the latent heat of the stripper overhead vapor and decreased the total equivalent works by 17.21% and 17.52%, respectively, compared with those of the conventional configuration. The minimal total equivalent works were 0.808 GJ/t CO 2 and 0.805 GJ/t CO 2 , respectively. The split stripping with overhead heat exchanger process is the third with a total equivalent work of 0.86 GJ/tCO 2 , while the simple vapor recompression configuration provided no reduction when compared with the conventional process.

The overall performance of the post-combustion chamber of steelmaking plants is controlled by the size of the gap that allows for the ambient air to merge with the hot gas stream exiting the fourth hole of an electric arc furnace. The impact of the opening coefficient (ratio between the gap area and the total area) on the post-combustion chamber performance has been investigated by a comprehensive 3D, steady, CFD simulation comprising radiative heat exchanges and detailed chemical reactions. It is found that no unique value of the opening coefficient is capable of optimizing all the relevant quantities of the evacuation process of exhaust fumes. A value of the opening coefficient comprised in the range 0.40–0.52 appears advisable in the investigated model geometry. It is shown that the accurate knowledge of some boundary conditions at the gap does not grossly modify the above serviceable range. Inefficiencies of the sample post-combustion chamber are highlighted and fan power savings are advised.

Solvent degradation represents one of the main operational drawbacks of the post-combustion CO2 capture process. Degradation not only induces additional costs for solvent make-up, it also impacts the process efficiency and its environmental penalty due to the emission of various degradation products. There is still a gap of knowledge about the influence of process operating conditions on degradation, making it currently impossible to predict the solvent degradation rate in CO2 capture plants. Morever, the reaction mechanisms corresponding to solvent degradation are very slow, significantly complicating its study in industrial units. In the present work, appropriate experimental equipment and analytical methods are developed for accelerating the degradation of monoethanolamine solvents (MEA). The relevance of accelerated conditions is established by comparing artificially degraded solvent samples with degraded solvent samples from industrial CO2 capture pilot plants. Two approaches are evaluated implying either discontinuous or continuous gas feed, this latest being the most representative of industrial degradation. The respective influences of the gas feed composition and the gas-liquid transfer are evidenced and quantified. Finally, the present study leads to a better understanding of solvent degradation in the CO2 capture process with MEA. More generally, it also evidences that accelerated conditions at laboratory-scale may provide relevant information for the study of slow phenomena taking place in large-scale industrial processes. Further works include the development of a kinetic model for MEA solvent degradation and the extension of this methodology to other promising solvents in order to facilitate the operation and large-scale deployment of CO2 capture.

Fossil fuels presently cater to majority of energy demand of the world. However, due to the climate change problem capture of CO2 emitted from the use of fossil fuels is emerging as a necessity. Alternately, developing technology with CO2 neutral fuels may reduce green house gas emission. Possible even better solution may be combining both of these options, i.e., employing CO2 capture process for energy efficient system using CO2 neutral fuels, say biomass. In this paper, such cogeneration system with CO2 capture using amine solution has been proposed. Thermodynamic modeling for the detail process has been implemented using ASPEN Plus®. Comparative study of performance relative to a similar base case plant without carbon capture has been presented. Results show post combustion CO2 capture process is better than pre-combustion CO2 capture process for such plants with net negative CO2 emission. Also degree of CO2 capture has to be optimized on the basis of the overall performance of the plant as higher CO2 capture affects thermodynamic and economic performance of the plant, specifically beyond certain value. In a net CO2 negative emission plant extent of CO2 capture is quite flexible and may be decided for optimum performance.