Coal-fired Power Plant Flue Gas Research Articles

Halogen (Cl, Br, I) regulation Cu-BTC for NH3-SCR: NO and Hg0 removal and mechanism analysis

Emissions of NOx and Hg0 in the atmosphere are primarily derived from coal-fired power plant flue gases. The control of these pollutants has emerged as a focal point of research in recent years. In this study, we synthesized a novel halogen-modified Cu-BTC catalyst designed for the synergistic removal of NO and Hg0. The results showed that: Cu-BTC catalyst maintained its original physicochemical properties even after being modified with different halogens (Cl, Br, I), and C-X (Cl, Br, I) bonds indicated the successful incorporation of halogens into the Cu-BTC. Furthermore, the catalytic performance was investigated through NH3-SCR method. Research indicated that halogens amplified the catalytic reduction of NO and the catalytic oxidation ability of Hg⁰. Furthermore, the effect of post-modification proved to be superior to pre-modification, following the order of Cl＞Br＞I. Under the conditions of 200 °C and 30000 h−1, the Cu-BTC-Cl catalyst exhibited the highest removal efficiency for both NO and Hg⁰, reaching 84.895 % and 76.841 %. While NO had a minor impact, NH₃ enhanced the removal of NO but inhibited the removal of Hg⁰. O2 significantly promoted pollutants removal, and the catalyst also showed strong resistance to both sulfur and water. The modified catalyst exhibited covalent C–Cl species, which effectively captured Hg0. Cu2+ participated in the removal of NO and Hg0, with partial transformation into Cu+.

Facile synthesis of Cu-BTC@biochar with controlled morphology for effective toluene adsorption at medium–high temperature

The development of adsorbents suitable for volatile organic compounds (VOCs) adsorption at medium–high temperature is urgently required for the control of VOCs in coal-fired power plant flue gas. In this study, a size-controlled broccoli-like Cu-BTC-loaded biochar composite (Cu-BTC@biochar) was synthesized with a facile one-pot method. Cu-BTC@biochar showed hierarchical pore structure features and significantly improved BET surface area (728.5 m2/g) compared with raw biochar (10.0 m2/g). The results of fixed-bed adsorption experiments show that Cu-BTC@biochar has outstanding toluene (typical components of VOCs) adsorption performance at the medium–high temperatures of 60 °C and 150 °C, the adsorption capacities can reach 501.8 and 88.8 mg/g, respectively. Molecular simulations were used to reveal the toluene adsorption mechanism and the results show that the van der Waals interaction plays an important role in the toluene adsorption process, but the electrostatic interaction of Cu-BTC@biochar has a significantly higher proportion than that of Cu-BTC (31 % vs 7 %), which is more pronounced when the temperature increases. Our findings demonstrate that this low-cost Metal-organic frameworks (MOFs) composite material presents great potential as the adsorbent for VOCs at medium–high temperature.

Sulfur/oxygen-doped porous carbons via NaCl-assisted thermolysis of a molecular precursor for CO2 capture

A novel combination of a cheap, readily available and easy to synthesize molecular precursor: p-toluenesulfonic acid (TsOH) and pore former NaCl was utilized for the production of sulfur/oxygen doped carbons. Dynamic and statistic adsorption capability of carbons on major coal-fired power plant flue gas components (CO2 (Carbon dioxide), Nitrogen (N2) and water vapor (H2O)) and surface chemical properties were investigated. NaCl addition increases micropore and larger pore development, but it marginally affects CO2 capture performance at low pressures due to similar pore volumes of carbons at ultramicropore (0.7 nm) range. However, dynamic adsorption experiments revealed that presence of large pores increases kinetics of adsorption. NaCl addition positively influences CO2 capture performance beyond 0.4–0.5 bar. Maximum CO2 uptake values are in the range of 0.78 mmol g−1 at 0.15 bar (298 K). CO2 uptake at low pressures (0.15 bar) at 298 K is connected to pore volume of micropores that has equal or smaller dimeter than 0.5 nm. It was demonstrated that presence of nonoxidized sulfur on carbon surface has a positive effect on CO2 adsorption at 0.15 bar (298 K and 313 K). There is no correlation found between CO2 uptake and oxygen or oxidized sulfur content, but there is a negative correlation between oxidized sulfur and CO2/N2 selectivity.

Sustainably Cultivating and Harvesting Microalgae through Sedimentation and Forward Osmosis Using Wastes.

Cost-effective nutrient sources and dewatering are major obstacles to sustainable, scaled-up cultivation of microalgae. Employing waste resources as sources of nutrients offsets costs for nutrient supplies while adding value through simultaneous waste treatment. Forward osmosis (FO), using simulated reverse osmosis brine, is a low-energy membrane technology that can be employed to efficiently harvest microalgae from a dilute solution. In this study, Scenedesmus obliquus, a green microalga, was cultivated with a fertilizer plant wastewater formula and simulated coal-fired power plant flue gas and then separated through either FO, with reverse osmosis reject model water as the draw solution, or sedimentation. Microalgal batches grown with simulated wastewater removed NH4+ within 2 days and reached nitrogen and phosphorus limitation simultaneously on Day 5. Sparging with the flue gas caused S. obliquus to produce significantly greater quantities of extracellular polymeric substances (30.7 ± 1.8 μg mL–1), which caused flocculation and enhanced settling to an advantageous extent. Five-hour FO trials showed no statistically significant difference (p = 0.65) between water fluxes for cultures grown with simulated flue gas and CO2-supplemented air (3.0 ± 0.1 and 3.0 ± 0.3 LMH, respectively). Reverse salt fluxes were low for all conditions and, remarkably, the rate of reverse salt flux was −1.9 ± 0.6 gMH when the FO feed was culture grown with simulated flue gas. In this work, S. obliquus was cultivated and harvested with potential waste resources.

Study on the characteristics of nitrogen dioxide adsorption and storage of coal residue in coal-fired power plants in goaf

In order to realize the storage of the residual coal in the goaf on the flue gas of the power plant, the adsorption characteristics of nitrogen dioxide in the flue gas of the power plant were studied. The Gaussian09 was used to study the adsorption process of NO2 molecules on coal at the density functional (DFT) B3LYP/6-311G level, and the model of NO2 adsorption by coal was established. Different quantities were obtained using orbital energy changes and molecular bond length changes. According to the principle of molecular adsorption, the adsorption of NO2 by coal is considered to be physical adsorption with endothermic heat. On the basis of simulation, using self-organized experimental devices, the single-component NO2 gas and the simulated coal-fired power plant flue gas were introduced into anthracite, bituminous coal and lignite. In single-component adsorption, the adsorption of NO2 by lignite increases with time. The time to reach equilibrium is related to the properties of the coal itself. In the process of simulated flue gas adsorption, the order of the adsorption amount of coal to flue gas is CO2 > NO2 > N2 > O2. In the simulated flue gas, coal is easy to absorb NO2 and CO2, and the competition between gases reduces the frequency of contact between NO2 and the coal surface. Simulation and experimental results show that coal has obvious adsorption characteristics for NO2, and it is feasible for the residual coal in the goaf to adsorb NO2 in the flue gas of power plants.

Selenium ligands doped ZnS for highly efficient immobilization of elemental mercury from coal combustion flue gas

At the upstream of electrostatic precipitator (ESP) or bag house (BH), using sorbents with excellent adsorption capacity is a common method for capturing mercury (Hg) from coal-fired power plant flue gas. ZnS, an inexpensively and conveniently prepared metal sulfide, can even be collected from nature, and is a promising candidate for its sulfur resistance. In this work, selenium ligands (Se 2− and Se 0 ) were introduced into ZnS for enhancing Hg 0 capture capability. The experimental results showed that the Hg 0 removal efficiency can reach 100% in a wide temperature range from 40 ℃ to 300 ℃ when the Se ratio was 30 wt% (30SZ). Compared with pure ZnS and Se powder, Se/ZnS were all exhibited an excellent absorbent capability. A long term experiment was imposed on 30SZ, and the sample adsorption capacity remained unchanged. Moreover, O 2 and SO 2 had insignificant effects on Hg 0 adsorption, NO showed a slight competition for Hg 0 adsorption. It was found that Se ligands (Se 2− and Se 0 ) and surface active S (S 2- and S) sites immobilized Hg 0 over the Se/ZnS surface, and in turn the adsorbed Hg 0 was basically converted to HgSe and HgS, and the adsorption mechanism was also proposed. With these advantageous performances, 30SZ is expected to be an economically feasible and scientifically sound sorbent. This work also provides a promising way for Hg 0 capture from coal combustion flue gas. • Inactive synthesized ZnS were functionalized to be highly efficient mercury sorbents. • The removal efficiencies can reach 100% in a wide temperature range from 40 to 300 ℃. • Se/ZnS had higher binding energy of Hg-Se to improve the adsorption capability. • The captured mercury is mainly converted into HgSe by chemisorption. • The components in the SFG have no obvious poison effects to synthesized 30SZ.

Carbon Capture From Flue Gas and the Atmosphere: A Perspective

Climate change has become a worldwide concern with the rapid rise of the atmospheric Co2 concentration. To mitigate Co2 emissions, the research and development efforts in Co2 capture and separation both from the stationary sources with high Co2 concentrations (e.g., coal-fired power plant flue gas) and directly from the atmosphere have grown significantly. Much progress has been achieved, especially within the last twenty years. In this perspective, we first briefly review the current status of carbon capture technologies including absorption, adsorption, membrane, biological capture, and cryogenic separation, and compare their advantages and disadvantages. Then, we focus mainly on the recent advances in the absorption, adsorption, and membrane technologies. Even though numerous optimizations in materials and processes have been pursued, implementing a single separation process is still quite energy-intensive or costly. To address the challenges, we provide our perspectives on future directions of Co2 capture research and development, that is, the combination of flue gas recycling and hybrid capture system, and one-step integrated Co2 capture and conversion system, as they have the potential to overcome the technical bottlenecks of single capture technologies, offering significant improvement in energy efficiency and cost-effectiveness.

Performance of transition metal (Cu, Fe and Co) modified SCR catalysts for simultaneous removal of NO and volatile organic compounds (VOCs) from coal-fired power plant flue gas

Emissions of NO and Volatile Organic Compounds (VOCs) in China are growing rapidly, thus it is necessary to develop a catalyst that can simultaneously remove them. In this study, a series of new V-W/Ti SCR catalysts modified by Cu, Fe and Co were prepared by wet impregnation method, which was used to simultaneously remove NO and typical VOCs (benzene and toluene) from coal-fired power plant flue gas. The catalyst activity evaluation was studied in selective catalytic reduction temperature window (260 °C, 300 °C, 340 °C, 380 °C and 420 °C) by a self-built device. Simulated flue gas was composed of 100 ppm benzene, 100 ppm toluene, 500 ppm NO, 1000 ppm SO2, 500 ppm NH3, 3.33% O2, and balanced N2, whose total flow was 750 mL/min. Characterization techniques such as SEM-EDS, XRD, XPS, and NH3-TPD were used to analyze the effect of Cu, Fe and Co loading on the catalyst's surface properties, physical structure, valence, and acid site, which further explained the removal efficiency result. The experimental results indicated that Cu0.1-V-W/Ti had the best denitration performance at low temperature and reached a maximum NO removal rate of 86.4% at 340 °C. All prepared catalysts had over 90% benzene removal and over 95% toluene removal rate. Cu0.1-V-W/Ti shows certain SO2 tolerance and has the potential to be used for simultaneous removal of NO and VOCs at SCR area of coal-fired power plants without extra capital cost.

Using Simulated Flue Gas to Rapidly Grow Nutritious Microalgae with Enhanced Settleability

Favorable microalgal nutrition from waste resources and improved harvesting methods would offset costs for a process that could be scaled up to treat pollution and produce valuable animal feed in lieu of soy protein. Co-benefits include avoidance of carbon dioxide emissions, which may provide an additional revenue stream when carbon markets begin to flourish. To sustainably achieve these goals at scale, barriers to microalgal production such as tolerance for waste streams and dramatic improvement in dewatering and settleability of the microalgae must be overcome. Presently, it is largely assumed that nutritious microalgae, including Scenedesmus obliquus, would be inhibited by SOx and NOx in flue gases and settle slowly as discrete particles. Studies conducted with a 2 L photobioreactor, sparged with simulated coal-fired power plant flue gas, demonstrated that both biomass productivity and settling rates were increased. The average maximum biomass productivity was 700 ± 40 mg L–1 d–1, which significantly exceeded that of the control culture (510 ± 40 mg L–1 d–1). Thirty-minute trials of modeled bulk settling showed rapid coagulation, likely facilitated by extracellular polymeric substances, and compaction when the cultures were grown with simulated emissions. Control cultures, not exposed to the additional toxicants in flue gas, settled as discrete particles and did not show any settling progress within 30 min. Of the SO2 sparged into the cultivation system, (111 ± 4)% was captured as either SO42– in the medium or fixed in the S. obliquus biomass. The stress of simulated-emissions exposure decreased the S. obliquus protein contents and altered the amino acid profiles but did not decrease the fraction of methionine, a valuable amino acid in animal feed.

In vivo creation of plasmid pCRT01 and its use for the construction of carotenoid-producing Paracoccus spp. strains that grow efficiently on industrial wastes

BackgroundCarotenoids are natural tetraterpene pigments widely utilized in the food, pharmaceutical and cosmetic industries. Currently, chemical synthesis of these compounds outperforms their production in Escherichia coli or yeast due to the limited efficiency of the latter. The use of natural microbial carotenoid producers, such as bacteria of the genus Paracoccus (Alphaproteobacteria), may help to optimize this process. In order to couple the ability to synthesize these pigments with the metabolic versatility of this genus, we explored the possibility of introducing carotenoid synthesis genes into strains capable of efficient growth on simple low-cost media.ResultsWe constructed two carotenoid-producing strains of Paracoccus carrying a new plasmid, pCRT01, which contains the carotenoid synthesis gene locus crt from Paracoccus marcusii OS22. The plasmid was created in vivo via illegitimate recombination between crt-carrying vector pABW1 and a natural “paracoccal” plasmid pAMI2. Consequently, the obtained fusion replicon is stably maintained in the bacterial population without the need for antibiotic selection. The introduction of pCRT01 into fast-growing “colorless” strains of Paracoccus aminophilus and Paracoccus kondratievae converted them into efficient producers of a range of both carotenes and xanthophylls. The exact profile of the produced pigments was dependent on the strain genetic background. To reduce the cost of carotenoid production in this system, we tested the growth and pigment synthesis efficiency of the two strains on various simple media, including raw industrial effluent (coal-fired power plant flue gas desulfurization wastewater) supplemented with molasses, an industrial by-product rich in sucrose.ConclusionsWe demonstrated a new approach for the construction of carotenoid-producing bacterial strains which relies on a single plasmid-mediated transfer of a pigment synthesis gene locus between Paracoccus strains. This strategy facilitates screening for producer strains in terms of synthesis efficiency, pigment profile and ability to grow on low-cost industrial waste-based media, which should increase the cost-effectiveness of microbial production of carotenoids.

Cross-Linked Polyphosphazene Blends as Robust CO2 Separation Membranes.

An effective cross-linking technique allows a viscous and highly gas-permeable hydrophilic polyphosphazene to be cast as solid membrane films. By judicious blending with other polyphosphazenes to improve the mechanical properties, a membrane exhibiting the highest CO2 permeability (610 barrer) among polyphosphazenes combined with a good CO2/N2 selectivity (35) was synthesized and described here. The material demonstrates performance stability after 500 h of exposure to a coal-fired power plant flue gas, making it attractive for use in carbon capture applications. Its CO2/N2 selectivity under conditions up to full humidity is also stable, and although the gas permeability does decline, the performance is fully recovered upon drying. The high molecular weight of these heteropolymers also allows them to be cast as a thin selective layer on an asymmetric porous membrane, yielding a CO2 permeance of 1200 GPU and a CO2/N2 pure gas selectivity of 31, which does not decline over 2000 h. In addition to gas separation membranes, this cross-linked polyphosphazene can potentially be extended to other applications, such as drug delivery or proton exchange membranes, which take advantage of the polyphosphazene's versatile chemistry.

The characteristics of arsenic in Chinese coal-fired power plant flue gas desulphurisation gypsum

Flue gas desulphurization (FGD) gypsum had broad application prospects in soil, but the trace heavy metals in FGD gypsum directly determine the severity of secondary pollution. In this work, we focused on arsenic in FGD gypsum for 70 samples from Chinese 20 provinces, investigating the characteristics of distribution and leaching by total contents, fractions, leaching tests, and species, and identifying arsenic mode of occurrence and possible risk for FGD gypsum applications. The result showed arsenic was generally approximately 15 mg/kg in Chinese FGD gypsum, and had an obvious geographical distribution by samples from different areas. Leaching tests showed a lower ability of arsenic release in short-term leaching as well as a large potential leaching risk by the sustained release of arsenic in long-term leaching for high-level arsenic FGD gypsum. X-ray photoelectron spectroscopy showed arsenic in FGD gypsum was mainly present as As(III), which has a higher toxicity. Based on our results, with regard of arsenic, most FGD gypsum is a safe material for soil application, but we did notice the potential risk of arsenic release due to long-term leaching and the content of arsenite.

Microstructural control of a SSZ-13 zeolite film via rapid thermal processing

A SSZ-13 zeolite (CHA type zeolite having a pore size of 0.37 × 0.42 nm2) can separate CO2 (0.33 nm) from larger molecules (N2 (0.364 nm) or CH4 (0.38 nm)) because of the molecular size differences. However, methods to control the non-zeolitic defects of SSZ-13 membranes are lacking. Here, we demonstrate that rapid thermal processing (RTP) of as-synthesized SSZ-13 films tunes their microstructural defect properties and increases their CO2 separation ability. The maximum CO2/N2 separation factor (SF) at 30 °C increased from ~2.9 to ~4.8 due to RTP because the defective region was reduced. Furthermore, the addition of water vapor (the third main component of coal-fired power plant flue gas) to the feed markedly improved the CO2/N2 SF of the RTP-treated SSZ-13 membrane; from ~4.3 at 50 °C (a representative flue gas stream temperature) under dry conditions to ~10.1 under wet conditions (vs. ~1.6 across the conventionally calcined counterpart). Furthermore, the less-defective RTP-treated SSZ-13 membranes achieved a CO2/CH4 SF as high as ~43.7 under wet conditions at 50 °C. Fluorescence confocal optical microscopy analyses complemented with the permeation modeling revealed that the reduced defect size after RTP (~2.2 nm against ~3.9 nm for the conventionally calcined counterpart) improved the CO2 permselectivity, even though the defect porosities were low (~0.1%).

Structured catalytic cartridges for SO2 oxidation in flue gases of coal-fired powerplants

Structured glass-fiber catalysts (GFC) are considered for application in the process of oxidation of endogenous SO2 directly in the media of flue gases from coal-fired powerplants. Such oxidation may be used for conditioning of flue gases to improve the efficiency of ash particulates in electrostatic precipitators. Comparison of Pt-based and vanadia-based GFC showed the much better performance by Pt/GFCs, having much higher activity and significantly lower ignition temperature (~300 °C). The best performance is demonstrated by Pt/GFC synthesized by high-temperature synthesis method in combination with spraying of active component precursor solution on the glass-fiber support surface instead of conventional impregnation. Application of structured GFC cartridges makes possible to apply them directly inside the flue gas duct with appropriate pressure drop. High permeability of such cartridges makes possible to apply them in the gas fluid contaminated with ash particulates with minimized risk of clogging. Beyond the mentioned advantages, application of GFC may be useful for resolution of related environmental problems: incineration of polyaromatic compounds and mercury-containing organic substances in flue gases.

An integrated process of chemical precipitation and sulfate reduction for treatment of flue gas desulphurization wastewater from coal-fired power plant

Flue gas desulphurization process in coal-fired power plants, produces wastewater with concentrated sulfate, chloride, metals and refractory organic compounds, which leads to serious pollution and corrosion problem during recycling. In this study, an integrated process of chemical precipitation and sulfate reduction for treatment of coal-fired power plant flue gas desulphurization wastewater was developed. Without additional of heavy metal trapping and strong oxidizing agents, chemical precipitation was performed as pre-treatment for removal of suspended solid (97%) in raw flue gas desulphurization wastewater. Comparison study on treatment of pre-treated flue gas desulphurization wastewater were performed in three parallelly operated sequencing batch reactors, by cultured sulfate reducing bacteria strain BY7, SR10 and SR3, respectively. This study demonstrated that strain BY7 and SR10 sulfate reducing bacteria were able to adapted to high-salinity flue gas desulphurization wastewater, with high efficiencies of sulfate reduction (86–94%), metals (70–100%) and refractory organic compounds removal (85–95%). The highest sulfate loading rate of 0.5 kg SO42−/m3·d was achieved in sequencing batch reactors with strain BY7 and SR10. Besides, a sustainable removal of chloride and fluoride were achieved (about 35% and 55%, respectively), which probably relate to co-precipitation or biosorption processes. Up to 14 out of 25 refractory organic compounds in flue gas desulphurization wastewater could be completely removed after integrated treatment process. As response to flue gas desulphurization wastewater stress, abundance of monounsaturated fatty acids were increased, and upregulated expression of genes related to salt detoxification were observed in SBR_BY7 and SBR_SR10. Therefore, this study provided a potential low-cost flue gas desulphurization wastewater recycling technology with simultaneously removal of sulfate, refractory organic compounds, heavy metal and salts.

Entropy generation analysis of heat and water recovery from flue gas by transport membrane condenser

Abstract The transport membrane condenser (TMC) has been used for heat and water recovery from coal-fired power plant flue gas. The capillary condensation of water vapor in membrane pore structure is the main gas separation mode. A lumped parameter model was established to study the heat and mass transfer in TMC. Recovered water and heat flow rates, water recovery ratio, heat recovery efficiency, and pressure drops were calculated. The temperature and humidity ratio distributions were displayed. The influences of structural parameters and operating conditions on the water and heat recovery performances were analyzed. In addition, the entropy generation model was proposed to calculate entropy variations and entropy generation components. The aim is to provide insights into TMC parameter selection and operation optimization. Moreover, the relationship between entropy generation components and TMC performances were confirmed. The results show that increasing packing fraction, or decreasing the membrane inner diameter or membrane pore size can improve the heat and water recovery performances. Besides, high water flow rates and low water temperatures have advantages in the operation. Increasing the mass/heat transfer driving force can enhance heat transfer performance, but the heat transfer entropy generation rate also increases. The maximum mass transfer entropy generation rate often corresponds to the best water recovery performance.

Separation of Carbon Dioxide from Real Power Plant Flue Gases by Gas Permeation Using a Supported Ionic Liquid Membrane: An Investigation of Membrane Stability.

The separation of carbon dioxide from coal-fired power plant flue gases using a CO2/N2-selective supported ionic liquid membrane (SILM) was investigated and the performance and stability of the membrane during operation are reported. The membrane is composed of a polyacrylonitrile (PAN) ultrafiltration membrane as a support and a selective layer of an ionic liquid (IL), 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide (EMIM Tf2N). The feasibility of large-scale SILM production was demonstrated by the formation of a square-meter-scale membrane and preparation of a membrane module. A flat-sheet envelope-type SILM module containing 0.67 m2 of the membrane was assembled. Prior to real flue gas operation, the separation behaviour of the membrane was investigated with single gases. The stability of the SILM during the test stand and pilot plant operation using real power plant flue gases is reported. The volume fraction of carbon dioxide in the flue gas was raised from approx. 14 vol. % (feed) to 40 vol. % (permeate). However, issues concerning the membrane stability were found when SO3 aerosols in large quantities were present in the flue gas.

Simulation of the Dynamics and Control Responses of the Carbon Dioxide Chemical Absorption Process using Aspen Custom Modeler

A rate-based dynamic model for the amine-based carbon dioxide absorption process was developed and built in Aspen Custom Modeler, which provides the convenient utilization of the property databank, thermodynamic models, controller models and solver facilities provided by the Aspen platform. The model was verified by the literature reported pilot plant dynamic data. A carbon dioxide absorption process with control system for the treatment of the coal-fired power plant flue gas was simulated using this model. The dynamic responses to the disturbances of the flue gas flow rate, temperature and carbon dioxide concentration as well as the set point changes of the absorption efficiency and lean solution loading are presented. The control scheme works well to reach the new steady state but requires a response time of about 9 hours. The model can be utilized to investigate the performance of alternative control schemes.

Alternative Approach to Current EU BAT Recommendation for Coal-Fired Power Plant Flue Gas Desulfurization Wastewater Treatment

Fossil fuel combustion is a serious environmental problem. Significant quantities of flue gasses and wastewater, requiring further treatment, are produced. This article compares three wet flue gas desulfurization (FGD) wastewater treatment methods: coagulation with precipitation using iron(III) ions—recommended by the European Union as the best available technique (BAT)—and two alternative advanced oxidation processes (Fe2+/H2O2 and Fe0/H2O2). Both oxidation processes that were used met the technical FGD wastewater treatment requirements of the BAT. The best treatment effects, expressed as pollutants’ removal, were obtained for the Fe2+/H2O2 process for 150/300 mg/L reagent doses. It allows effective removal of boron up to 212 mg/L and heavy metals up to below the detection limit <0.010 mg/L for Pb and <0.005 mg/L for Cu. Therefore, the Fe2+/H2O2 process could be an option for FGD wastewater treatment as an alternative to the BAT recommended iron(III)-based coagulation with precipitation. Additionally, an analysis of variance was applied to check the significance of the two independent variables and their interactions. Statistical analysis confirmed high efficiency and applicability of treatment process.

CO2 absorber coupled with double pump CO2 capture technology for coal-fired flue gas

Amine absorption method which is used for removing CO2 from coal-fired power plant flue gas has the high energy consumption and degradation rate, strong corrosion. In view of these defects and flue gas having low CO2 partial pressure, a new organic amine absorbent whose saturated absorption capacity can reach to 47.447.4L CO2/Lamine has been developed. Compared with MEA solution, its saturated absorption capacity has been increased by 29.1%, and the regeneration rate increased by more than 80%. The CO2 capture process flow has been analyzed, and ‘absorption heat pump +MVR heat pump’ double heat pump coupled low energy consumption CO2 capture system has been developed. Compared with traditional MEA technology, this system can save 38.32% energy, and its water saving rate can reach to 63%.