Explore the vast range of titles available.

Numerous mitigation techniques have been incorporated to capture or remove SO 2 with flue gas desulfurization (FGD) being the most common method. Regenerative FGD method is advantageous over other methods due to high desulfurization efficiency, sorbent regenerability, and reduction in waste handling. The capital costs of regenerative methods are higher than those of commonly used once-through methods simply due to the inclusion of sorbent regeneration while operational and management costs depend on the operating hours and fuel composition. Regenerable sorbents like ionic liquids, deep eutectic solvents, ammonium halide solutions, alkyl-aniline solutions, amino acid solutions, activated carbons, mesoporous silica, zeolite, and metal-organic frameworks have been reported to successfully achieve high SO 2 removal. The presence of other gases in flue gas, e.g., O 2 , CO 2 , NOx, and water vapor, and the reaction temperature critically affect the sorption capacity and sorbent regenerability. To obtain optimal SO 2 removal performance, other parameters such as pH, inlet SO 2 concentration, and additives need to be adequately governed. Due to its high removal capacity, easy preparation, non-toxicity, and low regeneration temperature, the use of deep eutectic solvents is highly feasible for upscale utilization. Metal-organic frameworks demonstrated highest reported SO 2 removal capacity; however, it is not yet applicable at industrial level due to its high price, weak stability, and robust formulation.

In this article, the results of full-scale experiments on the addition of a sodium sulfide to the CaCO3 slurry circuit in a wet flue gas desulfurization (WFGD) plant are presented. Tests are performed on two comparable WFGD installations (spray tower, 4 spraying levels and two stage gypsum de-watering by hydrocyclones and vacuum belt filter) which allows the investigation of the influence of lignite composition (lignite mined in Poland and the Czech Republic are compared) on the reduction in mercury emission. Additionally, the efficiency of precipitation of metals from the slurry (Hg, Zn, Pb, Cd, Cr, Cu, Ni, Fe, Se, and Mn) is investigated as the result of sulfide addition. For both objects, mercury re-emission from absorber occurs (the concentration of mercury in the chimney is higher than that before the WFGD absorber) and the sulfide addition to WFGD slurry stops this phenomenon. The addition of sulfide works effectively (mercury removal efficiency from flue gas reaches up to 88% for Polish tests and up to 87% for Czech Republic tests). For the tests in the Poland power plant, all of measured metals are precipitated from the slurry (precipitation of metals efficiency varied from 2% for zinc to 88% for mercury), but in the case of the test in the power plant in the Czech Republic, there is no effect on manganese, iron, and lead (precipitation of metals efficiency varied from 6.5% for copper to 86% for mercury). The addition of sulfide works effectively for lignite mined in Polish and Czech power plants under the conditions of similar WFGD installations.

The removal of SO 2 from flue gas remains a challenge. Adsorption-based separation of SO 2 using porous materials has been proposed as a more energy-efficient and cost-effective alternative to more traditional methods such as cryogenic distillations. Here we report a flexible hydrogen-bonded organic framework (HOF-NKU-1) that enables the sieving of SO 2 through the guest-adaptive response and shape-memory effect of the material. HOF-NKU-1 exhibits a high selectivity of 7,331 for the separation of SO 2 /CO 2 and a high SO 2 storage density of 3.27 g cm −3 within the pore space at ambient conditions. The hydrophobic nature of HOF-NKU-1 enables high dynamic SO 2 uptake and SO 2 recovery, even in conditions of 95% humidity. The SO 2 /CO 2 separation mechanism is studied through combinatorial gas sorption isotherms, breakthrough experiments and single-crystal diffraction studies, paving the way for the development of multifunctional shape-memory porous materials in the future. The efficient removal of SO 2 from flue gas remains a considerable challenge. Now a flexible hydrogen-bonded organic framework has been developed that exhibits high selectivity for SO 2 capture from flue gas mixtures, enabled by the material’s guest-adaptive behaviour and shape-memory properties.

The Ozone Monitoring Instrument (OMI) onboard NASA's Aura satellite has been providing global observations of the ozone layer and key atmospheric pollutant gases, such as nitrogen dioxide (NO2) and sulfur dioxide (SO2), since October 2004. The data products from the same instrument provide consistent spatial and temporal coverage and permit the study of anthropogenic and natural emissions on local-to-global scales. In this paper, we examine changes in SO2 and NO2 over some of the world's most polluted industrialized regions during the first decade of OMI observations. In terms of regional pollution changes, we see both upward and downward trends, sometimes in opposite directions for NO2 and SO2, for different study areas. The trends are, for the most part, associated with economic and/or technological changes in energy use, as well as regional regulatory policies. Over the eastern US, both NO2 and SO2 levels decreased dramatically from 2005 to 2015, by more than 40 and 80 percent, respectively, as a result of both technological improvements and stricter regulations of emissions. OMI confirmed large reductions in SO2 over eastern Europe's largest coal-fired power plants after installation of flue gas desulfurization devices. The North China Plain has the world's most severe SO2 pollution, but a decreasing trend has been observed since 2011, with about a 50 percent reduction in 2012-2015, due to an economic slowdown and government efforts to restrain emissions from the power and industrial sectors. In contrast, India's SO2 and NO2 levels from coal power plants and smelters are growing at a fast pace, increasing by more than 100 and 50 percent, respectively, from 2005 to 2015. Several SO2 hot spots observed over the Persian Gulf are probably related to oil and gas operations and indicate a possible underestimation of emissions from these sources in bottom-up emission inventories. Overall, OMI observations have proved valuable in documenting rapid changes in air quality over different parts of the world during last decade. The baseline established during the first 11 years of OMI is indispensable for the interpretation of air quality measurements from current and future satellite atmospheric composition missions.

Capturing CO2 from humid flue gases and atmosphere with porous materials remains costly because prior dehydration of the gases is required. A large number of microporous materials with physical adsorption capacity have been developed as CO2-capturing materials. However, most of them suffer from CO2 sorption capacity reduction or structure decomposition that is caused by co-adsorbed H2O when exposed to humid flue gases and atmosphere. We report a highly stable microporous coppersilicate. It has H2O-specific and CO2-specific adsorption sites but does not have H2O/CO2-sharing sites. Therefore, it readily adsorbs both H2O and CO2 from the humid flue gases and atmosphere, but the adsorbing H2O does not interfere with the adsorption of CO2. It is also highly stable after adsorption of H2O and CO2 because it was synthesized hydrothermally.

CO 2 capture, utilization and sequestration technology is currently a global research hotspot with increasing CO 2 emission and rising atmospheric temperatures. Flue gas desulfurization gypsum (FGDG) was used to realize CO 2 mineralization in waste NaOH lye in a pilot scale bubble tower. The effects of the ionic strength, CO 2 flow rate, reaction temperature, and liquid level in the reactor on the properties of the mineralization products and the CO 2 mineralization efficiency were investigated using thermogravimetric analysis, X-ray diffraction (XRD), scanning electron microscopy (SEM), and particle size analysis. The experimental results indicated that ionic strength, reaction temperature and CO 2 flow rate significantly influenced the CO 2 mineralization efficiency of FGDG. The CO 2 mineralization efficiency reached 92.15% under the optimized conditions (the ionic strength: 10 −2 mol·L −1 , CO 2 flow rate: 20 L·h −1 , reaction temperature: 60 °C, liquid level: 50 cm). The liquid level has a strong effect on the particle size distribution of mineralized products. A higher liquid level promotes the formation of mineralized products with smaller particle sizes. These products consist of a single cluster of crystals and the main component is calcium carbonate. The pilot scale results demonstrate optimized evidence for CO 2 mineralization using FGDG in waste lye. Therefore, this approach enables the comprehensive utilization of three types of waste-gas, liquid, solid- generated produced in coal-fired power plants.

Steam recovery from the spent gases from flues could be a key step in addressing the water shortage issue while additionally benefiting energy saving. Herein, we propose a system that uses organosilica membranes consisting of a developed layered structure to recover steam and latent heat from waste. Proof-of-concept testing is conducted in a running incinerator plant. The proposed system eliminates the need for a water supply while simultaneously recovering latent heat from the waste stream. First, the long-term stability of an organosilica membrane is confirmed over the course of six months on a laboratory-scale under a simulated waste stream. Second, steam recovery is demonstrated in a running waste incinerator plant (bench-scale), which confirms the steady operation of this steam recovery system with a steam recovery rate comparable to that recorded in the laboratory-scale test. Third, process simulation reveals that this system enables water-self-reliance with energy recovery that approximates 70% of waste combustion energy. Flue gas is a rich source of water and energy. Here, authors provide a state-of-the-art system anchored in organosilica membrane technology, attaining impressive steam recovery, delivering up to 70% energy recovery, and offering a promising remedy for global water shortages.

This paper, which focuses on emissions from China's coal-fired power plants during 1990–2010, is the second in a series of papers that aims to develop a high-resolution emission inventory for China. This is the first time that emissions from China's coal-fired power plants were estimated at unit level for a 20-year period. This inventory is constructed from a unit-based database compiled in this study, named the China coal-fired Power plant Emissions Database (CPED), which includes detailed information on the technologies, activity data, operation situation, emission factors, and locations of individual units and supplements with aggregated data where unit-based information is not available. Between 1990 and 2010, compared to a 479 % growth in coal consumption, emissions from China's coal-fired power plants increased by 56, 335, and 442 % for SO2, NOx, and CO2, respectively, and decreased by 23 and 27 % for PM2.5 and PM10 respectively. Driven by the accelerated economic growth, large power plants were constructed throughout the country after 2000, resulting in a dramatic growth in emissions. The growth trend of emissions has been effectively curbed since 2005 due to strengthened emission control measures including the installation of flue gas desulfurization (FGD) systems and the optimization of the generation fleet mix by promoting large units and decommissioning small ones. Compared to previous emission inventories, CPED significantly improved the spatial resolution and temporal profile of the power plant emission inventory in China by extensive use of underlying data at unit level. The new inventory developed in this study will enable a close examination of temporal and spatial variations of power plant emissions in China and will help to improve the performances of chemical transport models by providing more accurate emission data.

One of the main bottlenecks to deploying large-scale carbon dioxide capture and storage (CCS) in power plants is the energy required to separate the CO 2 from flue gas. For example, near-term CCS technology applied to coal-fired power plants is projected to reduce the net output of the plant by some 30% and to increase the cost of electricity by 60–80%. Developing capture materials and processes that reduce the parasitic energy imposed by CCS is therefore an important area of research. We have developed a computational approach to rank adsorbents for their performance in CCS. Using this analysis, we have screened hundreds of thousands of zeolite and zeolitic imidazolate framework structures and identified many different structures that have the potential to reduce the parasitic energy of CCS by 30–40% compared with near-term technologies. Developing capture materials and processes that reduce the energy required to separate carbon dioxide from flue gas in power plants is an important area of research. A computational approach to rank adsorbents for their performance in carbon dioxide capture and storage is now proposed, which will enable hundreds of thousands of zeolitic structures to be screened.

The adverse effects of climate change calls for the rapid transformation of manufacturing processes to decrease the emissions of carbon dioxide. In particular, a lower carbon footprint can be achieved by capturing carbon dioxide at the site of emission. Here we review the use of industrial effluents, waste and residues to capture carbon dioxide. Waste include steelmaking slag, municipal solid waste incinerator ashes, combustion fly ash, black liquor, paper mill waste, mining waste, cement waste, construction and demolition waste, waste from the organic industry, and flue gas desulfurization gypsum waste. Capture capacities range from 2 to 800 kg of carbon dioxide per ton of waste, depending on processes, waste type and conditions. Cement waste and flue gas desulfurization gypsum waste show the highest capture capacity per ton of waste.