Search

Flue gas desulfurization facilities produce flue gas desulfurization ash (FGDA), which has ecological and economic benefits. In this article, we explored the possibility and impact of using FGDA as the sole reinforcing filler to mechanically improve epoxidized natural rubber (ENR). The influence on the properties of the composites was examined. FGDA exhibits good interfacial interaction and compatibility with ENR, which improves the mechanical properties of ENR. When 15 phr FGDA was added, the tensile strength of the composites increased by approximately 41.4% compared with that of pure ENR. This work demonstrates the possibility of using FGDA as an effective and sole reinforcing material to enhance the properties of rubber materials. Highlights * FGDA improves the mechanical properties of ENR as a sole reinforcing filler. * FGDA reacts with ENR during vulcanization, enhancing compatibility. * Adding 15 phr FGDA to ENR increases the tensile strength by 41.4%. KEYWORDS composites, mechanical properties, rubber, vulcanization, 1 | INTRODUCTION Flue gas desulfurization ash (FGDA) is a substance created during the semidry desulfurization process, which involves using Ca[(OH).sub.2] to react with S[O.sub.2] generated from fossil fuel combustion [...]

Flue gas desulfurization ash (FGD) is a byproduct of flue gas desulfurization facilities. Its comprehensive utilization has attracted increasing interest. In this work, FGD is used as the reinforcing filler to improve the mechanical properties of carboxylated styrene‐butadiene rubber (XSBR). The effects of FGD on the curing characteristics, microtopography, and mechanical properties of the composites were studied. The results indicated that FGD can be uniformly dispersed in XSBR and effectively improve the mechanical properties of XSBR composites. The tensile strength of the XSBR/25FGD composite reaches 14.0 MPa, approximately 19.7% higher than that of pure XSBR. Even if the incorporation of FGD reaches 45 phr, the tensile strength is still higher than that of pure XSBR. The composites obtained a lower rate of thermal degradation than XSBR. The DMA properties of the composites may be improved by the appropriate amount of addition. This work provides a new method for making more effective use of FGD in the polymer field, which has significant economic and environmental benefits. [ABSTRACT FROM AUTHOR]

Mn–Ce–VOx/TiO2 (MnCeVTi), Mn–CeOx/TiO2 (MnCeTi) and Mn–VOx/TiO2 (MnVTi) nanocomposites as SCR DeNOx catalysts were synthesized by a modified sol–gel method. All catalysts shows high NOx conversion of over 90% at low temperature between 125 and 200 °C with GHSV of 30,000 h−1. MnCeVTi catalyst demonstrates the highest NOx conversion and produces the least byproduct N2O at 110–310 °C. The co-presence of Ce, V and Mn inhibits the growth of rutile, decreases crystallinity of anatase TiO2 and manganese oxides, reduces grain size, increases BET specific surface area and pore volume. There are most chemisorbed oxygen, appropriate Mn3+/Mn4+ and the synergistic effect of Ce and V on MnCeVTi sample. The acid sites on MnCeVTi are most below 280 °C and in widest temperature range. Lewis acid sites play a leading role in SCR reaction on MnCeVTi catalyst. These helps to optimize the SCR catalytic performance of MnCeVTi, on which E-R and L–H mechanism may coexist in the reaction. [ABSTRACT FROM AUTHOR]

CaSO3*0.5H2O content in CFB-FGD ash is more than 60%, leading to the different effect on the performance of cement compared to gypsum. The comparative study shows that the CFB-FGD ash with proper dosage is equivalent to gypsum on the setting time and the compressive strength of cement, but may lead to a significant decrease in the compressive strength with the excess amount, and the performance can be improved if combined with an appropriate amount of gypsum simultaneously. There have no obvious adverse effects upon the compatibility between the cement and the water reducing agent, and the bulk stability of cement in the application of the CFB-FGD ash with increasing content. The hydration product of C3A is C3A* CaSO3* 11H2O in the presence of CaSO3• 0.5H2O which is similar to AFm in chemical structure and in morphology of sheet form. The hydration of C3A with CaSO3*0.5H2O than CaSO4* 2H2O produces a larger amount of sheet-like AFm, other than columnar, needle-like AFt, which results in the different impact on the cement as mentioned earlier. [ABSTRACT FROM AUTHOR]

Commercial V2O5–WO3/TiO2 (abbreviated to VWTi) SCR catalysts are modified with Ce and different contents of Cu in wet impregnation method to improve their alkali metals resistance, which is beneficial for prolonging their service life. After K poisoning, NOx conversion of VWCeCuTi sample modified with 0.30% Ce and 0.05% Cu is 89% at 350 °C, which is obviously higher than that of VWTi with a 50% NOx conversion. A series of characterization tests were conducted and verified that the ratio of V5+ and the surface-active oxygen on VWCeCuTi sample increases due to the interaction between V, Ce and Cu. Additionally, with the addition of Ce and Cu, surface acid sites are increased and their stability is strengthened. The enhanced redox property and surface acidity contribute together to the excellent K resistance of VWCeCuTi catalyst. [ABSTRACT FROM AUTHOR]

The feasibility of using desulfurization ash generated from CFB+CFB-FGD process as cement admixture was studied. The effects of dry and wet ball mill on the fineness, compositions and activity of the desulfurization ash were also evaluated. The results show that the wet mill is more effective to the fineness of the desulfurization ash. After grinding for 90 minutes, the median particle size is about 3µm. The grinding has little effect on the composition of the desulfurization ash; grinding can effectively improve the activity of the desulfurization ash and achieve ultra-fine desulfurization ash to replace the 20% Portland cement mortar. The early strength is equivalent to the control formula. After 28 days, the strength of the mortar is better than the control formula. The cement concrete strength exceeds the control formula after 7 days, and reaches 120% of the strength of the control formula after 28 days. Grinding has little effect on the dimensional stability of the mortar. [ABSTRACT FROM AUTHOR]

Effects of nonthermal plasma (NTP) on the selective catalytic reduction of NO by CH (CH-SCR) over Co-In/zeolites were investigated in the presence of SO and HO at low temperatures (

The influence of balance gas mixture on decomposition of dimethyl sulfide was investigated experimentally by a wire-cylinder pulse corona reactor at room temperature. A new type of high voltage pulse generator with a thyratron switch and a Blumlein pulse-forming network was used in the experiments. The experiments were conducted at a fixed pulse frequency of 100pps. The DMS decomposition efficiency as well as energy yield was investigated using varying oxygen concentration (0.6–21.0%), humidity (0–1.0%) and different balance gas (air, N2, Ar). Breakdown voltage of DMS in Ar is lower than that of DMS in N2, both of which are proportional to the gas pressures. The conversion of DMS in Ar is more efficient than that in N2 and air at a fixed peak voltage. In addition, it is found that 5% oxygen is the optimum concentration in decomposition of DMS, due to higher conversion of DMS and relatively fewer yields of by products, such as O3, NO x and SO2. The highest DMS removal efficiency where the energy yield was 1.24mgkJ−1 was achieved with the gas stream containing 0.3% H2O in air. [Copyright &y& Elsevier]

The poisoning effect of single elements on commercial V2O5-WO3/TiO2 catalysts has been studied in the past decades. In this study, the combined effects of two multi-element systems (phosphorus-potassium and phosphorus-lead) on V2O5-WO3/TiO2 catalysts were studied by diverse characterizations. The results show that potassium and lead can result in the deactivation of catalysts to different degrees by reacting with active acid sites and reducing the amount of V5+. However, phosphorus displays slight negative influence on the NOx conversion of the catalyst due to the comprehensive effect of reducing V5+ amount and generating new acid sites. The samples poisoned by phosphorus–potassium and phosphorus–lead have higher NOx conversion than that by potassium or lead, because doped potassium or lead atoms may react with new acid sites generated by phosphate, which liberates more V–OH on the surface of catalysts and reduces the poisoning effects of potassium or lead on vanadium species and active oxygen species. [ABSTRACT FROM AUTHOR]

Direct leaching with NaOH can be an economically acceptable method for vanadium (V) and tungsten (W) recovery from spent selective catalytic reduction (SCR) catalysts. However, different chemical-physical characteristics of catalysts would affect the V and W leaching. In this paper, the V and W leaching behavior of various sources of SCR catalysts with a local difference (yellow and gray color) were systematically investigated with alkali leaching solution under ambient pressure. Different leaching efficiencies from yellow and gray color areas were correlated with oxidation states and species of V and W on catalyst surfaces, as characterized by X-ray photoelectron spectroscopy (XPS), Raman, Fourier transform infrared spectroscopy (FTIR), and other analytic methods. For the V leaching efficiency, the samples from a gray area of catalysts (40.0–51.0%) were lower than that from the yellow area (66.8–69.8%). The higher molar ratio of V3+ and a lower molar ratio of V5+, and the lower total V content on the surface of the samples from the gray area could be the main reasons for the lower V leaching efficiency. As for the W leaching efficiency, the samples from the gray area (44.6–57.3%) were slightly higher than that from the yellow area (38.0–52.6%) of catalysts. The less total W content of surface species and stronger interaction among V–W–Ti of yellow area samples resulted in the lower leaching efficiency. These differential leaching efficiencies needed to be taken into consideration for recovering V and W from spent SCR catalysts. [ABSTRACT FROM AUTHOR]

Abstract In this study, the deactivation of commercial V 2 O 5 -WO 3 /TiO 2 selective catalytic reduction catalysts by Pb was discussed primarily, and the combined promotive effects of SO 2 and HCl on Pb-poisoned V 2 O 5 -WO 3 /TiO 2 catalysts were studied. The results show that the treatment with SO 2 and HCl markedly improves the NO x conversion of Pb-poisoned catalysts. SO 2 and HCl react with Pb chemisorbed on V 2 O 5 , which increases effectively the ratio of V5+ and active oxygen species and the amount of acid sites. Graphical abstract Unlabelled Image Highlights • Pb-poisoned commercial SCR catalyst is reactivated by treatment with HCl and SO 2. • XPS confirms the transformation of V5+ species into V4+ species after doping by Pb. • Active oxygen species are generated after the treatment with HCl and SO 2. • V4+ transforms to V5+ in the catalyst after exposing to HCl and SO 2. • Results indicate the promotive effect of SO 2 and HCl on Pb-poisoned catalysts. [ABSTRACT FROM AUTHOR]