Flue Gas Emissions Research Articles

Towards the co-benefits of carbon capture, utilization and sequestration: A life cycle assessment study for steel slag disposal

Achieving decarbonization in the steel industry is of paramount importance for global carbon neutrality. Given the unavoidable generation of calcium-containing steel slag and carbon-rich flue gas emissions in the steelmaking process, steel slag carbonation is considered a CCUS technology capable of achieving pollution and carbon reduction in the steel industry. This study conducts a life cycle assessment (LCA) of the environmental impacts generated within the system boundaries of mainstream hot braising steel slag treatment and a novel carbonation steel slag approach. Results of the research demonstrate that the carbonation route based on carbon capture, utilization, and storage (CCUS) technology reduces the global warming potential (GWP) by 480% compared to the mainstream hot braising route, yielding −76.78 kg CO2 eq./t steel slag. The carbonation route also mitigates the environmental impact of pollutant emissions; however, it introduces a burden shifting associated with energy and resource consumption. Furthermore, to tackle the challenges of industrial application of steel slag carbonation, this study has explored upgrading schemes and proposed a future carbonation steel slag route that achieves process upgrades. By enabling carbonation of flue gas and improving carbonation efficiency, this route is forecasted to elevate the potential of carbon footprint reduction from 5% to 15% throughout the entire life cycle of steelmaking process. The study confirms that steel slag carbonation is a viable carbon-negative technology, delivering a substantiated CCUS solution for achieving co-benefits of pollution and carbon reduction in the steel industry.

Plastic-to-energy: Process and economic–environmental assessment of a recycling technology

Plastic waste becomes a major global concern as amounts of plastic waste are rising every year. To solve this problem, various recycling methods of plastic waste have been introduced including a waste-to-energy (WTE). Adopting plastic waste as feed source to WTE process has advantages but it accompanies economic and environmental issues followed by flue gas emission and energy generation efficiency. Therefore, this study developed an integrated assessment considering environmental threat and economic feasibility of targeting plastic waste as WTE fuel while maximizing net present value (NPV). A recycling method with WTE was proposed developing a power plant producing electricity which is based on plastic calorific value and a case study considering flue gas components. Furthermore, a sensitivity analysis identified variables that could influence the economic aspects of the process. As results, the FO cases, which secures residual heat through additional combustion reaction as a flue gas treatment method and generates electricity, had positive NPVs of 20.55, 19.90, 19.39, 18.93, and 18.50 million USD, respectively. Furthermore, sensitivity analysis indicates that the cost of electricity is the main contributor of NPV.

Examining waste-to-energy technology potential through the pilot project of Bantargebang Waste-to-Energy Power Plant

Municipal waste management in Indonesia, particularly Jakarta, poses a significant environmental challenge. Jakarta has been relying on the Bantargebang landfill to address its waste disposal needs for many years. Due to the persistent accumulation of waste, the Bantargebang landfill nears its maximum capacity. In response, a Waste-to-Energy (WtE) power plant was introduced in Bantargebang, serving as a pioneering initiative for WtE technology implementation in Indonesia. The Bantargebang WtE Plant employs incineration technology to convert municipal waste into electricity. Despite its usefulness, there are general environmental concerns about WtE plants, specifically focusing on their emissions and the potential presence of hazardous substances This research assesses the Bantargebang WtE Plant’s performance based on 2022 operational data, specifically examining waste reduction efforts and comparing incineration byproducts, including FABA (Fly Ash, Bottom Ash), and flue gas emissions, against government standards. The study indicates the plant can reduce waste mass by 96.5%. Furthermore, the WtE plant’s byproducts align with government standards for flue gas emissions and FABA residue. These results emphasize the potential of large-scale WtE power plants to achieve sustainable waste management goals in Indonesia. Nonetheless, there are opportunities for maximising waste accumulation reduction performance and enhancing operational value of WtE plant.

Development of Ecologically Sustainable Green Products Usable in the Agro-Sector as a Result of Innovative Technical Education

Growing concern of carbon dioxide emissions, greenhouse effects and rapid depletion of fossil fuels raise the necessity to produce and adopt new eco friendly sustainable alternatives to the internal combustion engine driven vehicles. For this reason, in the last decade, electric vehicles have become in some way widespread, principally because of their negligible flue gas emissions and lesser reliance on oil. Although electric cars were introduced many years ago, agriculture electric vehicles have recently gained attention. The world of agriculture has changed, small specialized farm utility vehicles are now used for a specific purpose, and in several cases they have an electric engine.

Ammonia blends for gas-turbines: Preliminary test and CFD-CRN modelling

Ammonia, with its high hydrogen density, cost effectiveness and ease of storage, is emerging as a potential fuel to meet decarbonisation targets in various sectors. However, the combustion of pure ammonia poses challenges due to its low calorific value and reactivity. Existing gas turbine combustion systems, refined over decades with conventional fuels, struggle to maintain comparable flue gas emission concentrations when burning ammonia.Overcoming this challenge requires a paradigm shift in gas turbine combustion, with implications for chemistry and combustor design methodology. Research into the chemical kinetic mechanism for ammonia combustion worldwide reveals differences in flame radical pools compared to methane combustion. The dominant NOx formation mechanism shifts to a "fuel-bound nitrogen" type, which differs from the "thermal" mechanism in hydrocarbon and hydrogen combustion.The integration of chemical reaction rates into Computational Fluid Dynamics (CFD) models with transport equations results in impractical computational times for industrial applications. Therefore, streamlined approaches such as chemical reaction reduction methods are being developed. This involves the construction of lumped parameter models (Chemical Reactor Network - CRN) to identify key parameters that affect species production. A reliable CRN implementation involves the identification of critical volumes using a preliminary CFD approach (CFD-CRN).This paper analyses preliminary experimental tests by Baker Hughes on an industrial burner using different ammonia, hydrogen, and methane fuel mixtures. The NOx results show a different behavior between methane and hydrogen. While the detailed mechanisms behind these results remain open questions, the CFD-CRN modelling approach is adopted. A proposed CRN is investigated for methane, hydrogen, and ammonia blends, providing insight into key parameters and a reasonable physical explanation for the different NOx results. A single calibration parameter (ϕpilot/ϕref) is used to predict accurately NOx emissions using experimental data available from experimental campaign.

Mechanism of O2-promoted NO adsorption on activated carbon: An experimental and computational study

Activated carbon can be used to control NOx emissions in low-temperature flue gas, while improving its performance is challenging. NO adsorption on activated carbon was found significantly promoted with the presence of O2. Based on the analysis of NO adsorption characteristics under different atmospheres and corresponding desorption characteristics, NO oxidation, NO2 migration and further conversion on activated carbon are proposed to cause the significant increase in NO adsorption capacity. Quantum chemical calculations conducted on the adsorption and reaction pathways of NO, O2, and NO2 on different carbonaceous models clarified that the pathway of O2-promoted NO adsorption on activated carbon can be divided into two stages. In the first stage, O2 adsorbs on active carbon atoms near the hydroxyl functional group and undergoes an oxidation reaction with gaseous NO to generate NO2. In the second stage, the desorbed NO2 is re-absorbed on the saturated carbon atoms; the N-down adsorption configuration of NO2 will not convert, while the O-down adsorption configuration of NO2 will oxidize the active site to form C-O and release NO; the C-O further reacts with the gaseous NO2 to form NO3- which stably remains. There are two types of active sites involved in the pathway. The active carbon atoms near the hydroxyl functional groups mainly play a catalytic role in the oxidation of NO, while the saturated carbon atoms mainly store nitrogen-containing components. The results can help improve the performance of activated carbon in adsorbing NO in low-temperature flue gas.

A novel process for ultra-low emission of flue gas by adding waste heat steam

This work offers a new process for removing fine particles from converters by adding steam from a waste heat boiler. The fine particles were enlarged using the pre-technique of water vapor condensation which was initially validated its available in a lab-scale experimental system. Following the steam was introduced into the secondary scrubber system to reform converter dust removal system, the mass concentration of the dust at the stack outflow decreased from approximately 30 ∼ 40 mg/m3 to 6 mg/m3. The morphology and elemental content of the fine particles released from the chimney vents, with and without steam injection, were analyzed by SEM and EDS, respectively, to further investigate the particle size range and chemical composition of the fine particles eradicated by steam injection. It was discovered that the growth and removal of the 200–300 nm iron–rich fine particles can be facilitated by vapor condensation. This work provides a new idea for achieving ultra-low emission transformation of the converter wet dust removal process.

Unveiling the potential of membrane in climate change mitigation and environmental resilience in ecosystem

Carbon capture technologies are becoming increasingly crucial in addressing global climate change issues by lowering CO2 emissions from industrial and power generation activities. Post-combustion carbon capture, which uses membranes instead of adsorbents, has emerged as one of promising and environmentally friendly approaches among these technologies. The operation of membrane technology is based on the premise of selectively separating CO2 from flue gas emissions. This provides a number of different benefits, including improved energy efficiency and decreased costs of operation. Because of its adaptability to changing conditions and its low impact on the surrounding ecosystem, it is an appealing choice for a diverse array of uses. However, there are still issues to be resolved, such as those pertaining to establishing a high selectivity, membrane degradation, and the costs of the necessary materials.In this article, we evaluate and explore the prospective applications and roles of membrane technologies to control climate change by post-combustion carbon capturing. The primary proposition suggests that the utilization of membrane-based carbon capture has the potential to make a substantial impact in mitigating CO2 emissions originating from industrial and power production activities. This is due to its heightened ability to selectively absorb carbon, better efficiency in energy consumption, and its flexibility to various applications. The forthcoming challenges and potential associated with the application of membranes in post-carbon capture are also discussed.

Excellent Mercury Removal in High Sulfur Atmosphere Using a Novel CuS-BDC-2D Derived by Metal-Organic Frame.

To effectively remove high concentrations of mercury in a high sulfur atmosphere of nonferrous smelting flue gas, a novel two-dimensional CuS-MOF (CuS-BDC-2D) material is synthesized by anchoring S to Cu sites in the Cu-BDC MOF. The highly dispersed CuS active sites and MOF framework structural properties in CuS-BDC-2D enable efficiently collaborate in capturing mercury. CuS-BDC-2D exhibits a layered floral structure with high specific surface area and thermal stability, with poor crystallinity. Compared to CuS and the three-dimensional CuS-MOF (CuS-BDC-3D) structure, CuS-BDC-2D demonstrates significantly higher mercury capture capacity due to the high exposure of active sites and defects sites in the two-dimensional material. Moreover, CuS-BDC-2D exhibits excellent resistance to sulfur, maintaining its high efficiency in removing Hg0 even at high levels of sulfur dioxide (SO2), such as 5000-20,000 ppm. The superior performance of CuS-BDC-2D makes it suitable for controlling mercury emissions in actual nonferrous smelting flue gas. This discovery also paves the way for the development of new mercury adsorbents, which can guide future advancements in this field.

Silica aerogel nanoparticle-stabilized flue gas foams for simultaneous CO2 sequestration and enhanced heavy oil recovery

With declining conventional reserves, tapping heavy oils generates substantial emissions yet is essential to meet energy demands. This study pioneers an integrated approach using silica aerogels to develop thermally stable flue gas foams for enhanced CO2 sequestration and heavy oil recovery. Microfluidic experiments and molecular dynamics simulations revealed a 5-fold decrease in gas diffusion rates for aerogel-stabilized versus pure surfactant foams at 95 °C due to the ultralow thermal conductivity of the nanoparticle coating layer. The thermally stable nanoengineered foams demonstrated a remarkable 81.23% CO2 trapping efficiency in heterogeneous cores, surpassing conventional flue gas foam. Additionally, three-dimensional simulations in an oil reservoir model showed improved vertical conformance and oil recovery with aerogel-stabilized foam. The exceptional insulating properties redirected heat downward to enhance sweep efficiency. This novel concept transforms flue gas emissions into value-added foams for concurrent environmental and productivity benefits during heavy oil development.

N2 and Ar dilution on the premixed biogas jet flame under external acoustic enforcement

In this study, combustion instabilities and flue gas emission changes under different dilutions of N2 (nitrogen) and Ar (argon) of a promising biogas mixture (70% CH4 - 30% CO2) in the fight against greenhouse gas emissions were investigated. In the experiments, additions were made from 0% to 50% at intervals of 10% for both gases. In order to detect the instability of the flame, external acoustic enforcements at different frequencies was applied through the speakers placed in the combustion chamber arms. The dynamic pressure fluctuation values were recorded. The results showed that low dilution ratios were effective in reducing flame instability for both inert gases. However, as the dilution ratio increased, the fuel/air mixture became leaner and blowoff occurred. In the case of comparing two different gases, it has been observed that the effect of argon gas on reducing dynamic pressure fluctuation is higher. Burner outlet temperature and brightness values of the flame decreased in both Ar and N2 dilution. CO and NOx emissions increased with increasing diluent volume for all dilution conditions. When the emissions of the two diluent gases are compared, the CO emission, which was 3134 ppm in the undiluted condition, increased up to 4949 ppm in 50% Ar dilution, while it increased to 4521 ppm in 50% N2 dilution.

Experimental study on the flexible peak shaving with pulverized coal self-preheating technology under load variability

The integration of renewable energy sources into power grids has led to power fluctuations, necessitating coal-fired power units to provide flexible peak shaving. The pulverized coal self-preheating technology can potentially provide broad-load regulation and rapidly respond to load changes. In this study, the impact of the self-preheating technology on fuel preheating modification, combustion characteristics, and NOx emissions are investigated. Load-stabilization bases are proposed based on preheating temperature, preheated coal gas composition, combustion temperature, and flue gas emissions. Load change rates are calculated using these bases to character the load response. The results demonstrate that the preheated fuel has similar properties as the highly reactive gaseous fuel and exhibits excellent ignition and combustion performances at 25 % load. Preheating treatment improves combustion efficiency, and burnout ratio and reduces NOx emissions. The NOx concentration approaches the ultra-low emission standard at 50 % load. Four load-stabilization bases, covering the preheating and combustion sides, comprehensively characterize the load response performance. The rates based on preheating indicators and combustion indicators maximize to 3.30 %/minute and 2.71 %/minute, respectively. The load change rate in the ramp-up phase is higher than that in the ramp-down phase, which is related to the effective internal heat storage carrier and external thermal insulation conditions. The driving force formed by high load step ranges and the deviation from the full load capacity are conducive to increasing the load change rates.

Application study for the high CO2 tolerant Chlorella strain by flue gas culture: Evaluation of growth performance and adaptive mechanisms

The application of microalgae for CO2 biosequestration of flue gas emissions from coal-fired power plants has attracted widespread attention. In this study, one high CO2 tolerant Chlorella strain (LAMB 31) screened by previous experiments was cultured with flue gas of a power plant, whose multiple growth performance and the adaptive mechanisms under the flue gas were investigated. The results indicated LAMB 31 grew well under the flue gas with a specific growth rate of 0.15/d and a maximum carbon fixation rate of 0.24 g/L/d. Correspondingly, LAMB 31 increased intracellular chlorophyll and fatty acid content (especially unsaturated fatty acids), while relatively low intracellular arsenic and mercury were accumulated, showing advantages of LAMB 31 for further food/feed and biodiesel production. Transcriptional results showed that enhancing carbon turnover and storage processes were the major mechanism for LAMB 31 adapting flue gas culture. Furthermore, inhibited uptake and enhanced detoxification of heavy mental were also found, verifying that LAMB 31 could effectively control the intracellular heavy mental accumulations. This study comprehensively evaluated the growth performance, elucidated possible adaptive strategies of Chlorella sp. responding to the flue gas, and provided further directions for the subsequent applications of LAMB 31 biomass.

The Combination of Simulation and Heat Pump Technology for the Treatment and Reconstruction of “Wet Plume” in fossil-fuel power station

The saturated wet flue gas discharged from the power plant chimney after wet desulfurization often forms a thick “white plume” at the chimney’s mouth. This “wet plume” phenomenon has a very bad impact on the lives of local people, and it will also cause corrosion damage to surrounding equipment while polluting the environment. This paper simulates the “wet plume” phenomenon caused by flue gas emissions under different flue gas parameters and environmental parameters by using the CFD simulation method and the new technology of “smoke tower integration” of power plant emissions. Through the simulation data, the “wet plume” pollution change is studied, which provides a reliable theoretical basis for the design of new power plants and the reconstruction of old power plants. At the same time, through the simulation data, the combination of flue gas indirect condensation technology and heat pump technology is selected to realize the recovery and reuse of flue gas waste heat and realize the dual embodiment of social value and practical value.

The effect of the ceramic foam cell structure on the combustion performance of porous media burner: experimental study

To investigate the effect of the ceramic foam cell structure on the combustion characteristics, a porous media burner(PMB) composed of foamed ceramic plates with Kelvin and WP cell models as structural features was designed and developed. The combustion chamber temperature, lean combustion limit, radiation efficiency and flue gas emission characteristics of the burner were analysed in the combustion of methane. The results show that with the same pore density, skeleton diameter and operating parameters, the combustion chamber temperature and radiation efficiency of the WP model are higher than those of the Kelvin model, while the CO and NOx emissions of WP model have an opposite tendency. When the ceramic foams are composed by WP cell model, under the same pore density and operating parameters, the burner has better combustion performance when the skeleton is thin. The combustion chamber temperature and radiation efficiency are higher, CO and NOx emissions are lower, and the lean combustion limit equivalent ratio is lower.

Preheating and Humidification of the Combustion Air to Increase the Hot Water Boiler Efficiency

Energy efficiency is one of the most pressing topics now. Energy consumption in-creases as living standards rise. Efficient heat production, i.e. efficient use of energy, is achieved with optimal boiler load. The second pressing issue is the protection of the environment from pollution. The process of burning different types of fuels to produce heat or energy results in emissions that can have negative impacts on the environment. One of the solutions to improve air quality is to reduce emissions from heating plants during their production. The scientific paper considers the possibility of a preheating and humidification for combustion air system to increase the efficiency of the boiler and reduce the amount of harmful emissions in flue gases. The boiler efficiency values were calculated before and after the installation of the preheating and humidification system for the combustion air, and measurements of the flue gas analysis were carried out using a Testo 350 flue gas analyzer. Calculations and measurements for flue gas analysis have shown that the combustion air preheating and humidification system increases the boiler house efficiency by 15 % and re-duces nitrogen oxide emissions by 70 %.

Investigation of the NO removal process of ultra-low temperature adsorption-rapid regeneration

NO removal facility installed at the very tail-end of the flue gas could reduce the effects of dust and SO2 poisoning, the problem is to figure out how to remove NOx at ultra-low temperature. Relying on rotary reactors, a NOx adsorption-enclosed regeneration process (NAER) was proposed, by which NOx is adsorbed onto the adsorbent at ambient temperature and then to on-site degrade in a high-temperature and enclosed environment with the high-concentration CO. Metal-doped activated carbon emerged as the optimal catalyst for shortening the cooling temperature difference. The results indicated that the maximum adsorption capacity for NO is 38.67 mg/g at 50 ℃, and NO conversion reaches exceed 90 % at 250 ℃ when 1400 ppm CO and 700 ppm NO are introduced into the reactor. The novel enclosed high-concentration of CO reduction regeneration encourages more NO to participate in the reaction, promoting the deep decomposition of nitrate and avoiding the overflow of NOx at the outlet. The difference between the breakthrough time and regeneration time spans 12–21 min. The carbon consumption is 0.0087 %/min, ensuring the long-term and continuous operation of the material. The current study explains the reaction mechanism of NO adsorption via in-situ FTIR. Life cycle assessment method is applied to analyze NAER’s emission standards, while life cycle inventory method calculates the economic cost, which stands at 287.06 RMB. The reduced cost is primarily reflected in the energy and raw materials inputs. The proposed process holds significant potential for optimizing the ultra-low emission of flue gas.

Feasibility Analysis of Municipal Solid Waste Incineration for Harmless Treatment of Potentially Virulent Waste

The outbreak of major health emergencies, such as the COVID-19 pandemic, has posed numerous challenges to waste management. Environmentally sound treatment of such epidemic-related municipal solid waste (MSW) plays a vital role in interrupting virus transmission. In this study, the furnace type, incineration process and control parameters of an MSW incinerator were comparatively analyzed with those of a medical waste incinerator and hazardous waste incinerator according to China’s MSW incineration pollution control standards. In addition, changes in flue gas emissions data before, during and after the outbreak of the pandemic were empirically analyzed. The study revealed the following: (1) the feasibility of MSW incinerators to meet the harmless disposal of potentially viral municipal solid waste (PVMSW); (2) the priority order of incinerator types for MSW incinerators in the disposal of potentially virulent waste was grate furnace incinerator > fluidized bed incinerator > cement kiln; and (3) when MSW incinerators treated PVMSW, the emissions of dioxin compounds in the flue gas fluctuated between 0.00052 and 0.031 ng TEQ/m3, HCl emissions fluctuated between 1.6 and 23.742 mg/m3, CO emissions fluctuated between 0.18 and 59.15 mg/m3, heavy metal emissions fluctuated between 0.000008 and 0.855 mg/m3, and particulate matter emissions fluctuated between 0.64 and 12.13 mg/m3. All emissions met the flue gas emission standards. This study verified the feasibility of using MSW incinerators to treat PVMSW during a sudden major pandemic and provided a theoretical basis for the environmentally sound collaborative treatment of PVMSW and a reference for the emergency management and sustainable development of MSW.

Combustion of chicken manure and Turkish lignite mixtures in a circulating fluidized bed

Burning chicken manure (CM) with lignites may be a promising method to ensure waste management. In this study, a circulating fluidized bed boiler (CFBB) system was designed, manufactured, and tested for the disposal of CM in poultry farming. Combustion and co-combustion tests of CM and Kale Lignite (L) were carried out in the CFBB to determine the effect of excess air ratio and CM share in the fuel mixture on combustion efficiency and flue gas emissions. As the CM share in the mixture increased, the combustion efficiency increased from 86 % to 95 %. It was observed that while CO emissions increased, SO2 and NOx emissions decreased with respect to CM share. CO emissions ranged from 726 to 2241 mg/Nm3 for 100%L and between 838 and 2450 mg/Nm3 for 100%CM. The NOx emissions changed between 177.5 and 240 mg/Nm3 for 100%CM; however, it was 276.3 mg/Nm3 for 100%L. While SO2 emissions (average) for 100%L were around 5200 mg/Nm3, as the CM share in the fuel mixture increased, emissions decreased, and when they became zero for 100%CM. CO emissions decreased as the excess air ratio increased. SO2 and NOx emissions increased as the excess air ratio increased in almost all fuel mixtures. This combustion system was proposed for waste disposal, emission reduction, and usage of domestic sources. Photovoltaic panels can support this system and meet farms' operational energy requirements away from the grid. Combustion efficiency can be increased by operating the system at oxy-firing mode instead of air-firing.

Research on carbon dioxide capture and mass transfer in hydro-jet cyclone

Steel smelting has a large amount of flue gas emissions and high carbon capture costs, making it one of the “heavy disaster areas” for carbon dioxide (CO2) emissions. This article develops a hydro-jet cyclone (HJC) by coupling the gas phase swirling flow field with the liquid phase jet flow field, and proposes a carbon capture technology for smelting flue gas. During the dispersion process of liquid phase microelements, there was simultaneous rotation and revolution of droplets, which enhances the gas–liquid mass transfer process. The surface renewal effect increases the effective specific interface area, and the interface oscillation effect was beneficial for reducing the mass transfer resistance on the liquid side. A model for the effective phase interface area (ae) of HJC was first proposed for different jet hole, with a maximum ae of 5358.95 m2·m−3.In the CO2-NaOH system, the absorption efficiency of CO2 was 88.9 %. This article supplements HJC's research on carbon capture and gas–liquid mass transfer by optimizing the size of the jet hole, which was beneficial for the development of efficient carbon capture equipment in the steel industry and further promotes the sustainable development of the steel industry.