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[Display omitted] • The generation characteristics of ABS/AS under non-catalytic conditions were investigated. • SO 3 and NH 3 enhanced ABS/AS generation and deposition. • The initial deposition temperature of ABS/AS is exponentially correlated with the product of SO 3 and NH 3 concentration. • Liquid ABS deposited firstly, the mixture of H 2 O, ABS and H 2 SO 4 or AS and (NH 4) 3 H(SO 4) 2 deposited at low temperature. The generation and deposition of ammonium bisulfate (ABS) in flue gas caused serious blockage and corrosion to the air preheater, which seriously affect the safe and economic operation of coal-fired power plants. The generation and deposition of ABS/ammonium sulfate (AS) under non-catalytic conditions were studied on a simulated air preheater test bench, and FT-IR and XRD tests were performed to characterize the products under different conditions. Experimental results show that the generation of ABS/AS is complicated and controlled by the concentration of SO 3 and NH 3 , the ratio of SO 3 to NH 3 (SO 3 /NH 3) and deposition temperature. Under the same SO 3 conditions, ABS/AS generation rate under different SO 3 /NH 3 conditions is 1:2 > 2:1 > 1:1. The initial deposition temperature of ABS/AS will increase with the corresponding increase of SO 3 and NH 3 concentration, and is exponentially correlated with the product of SO 3 and NH 3 concentration in flue gas. In the temperature range 390–223 °C, ABS generated and deposited under all conditions, and in the temperature range 223–131 °C, the mixture of H 2 O, H 2 SO 4 , and ABS generated and deposited when SO 3 /NH 3 is 2:1, and AS with a small amount of (NH 4) 3 H(SO 4) 2 generated and deposited when SO 3 /NH 3 is 1:1 and 1:2. [ABSTRACT FROM AUTHOR]

[Display omitted] • The deposition and transformation of ammonium bisulfate (ABS) on fly ash under variable temperature conditions was investigated. • Fly ash enhanced ABS deposition by trapping and absorbing effects. • ABS deposition is positively correlated with the product of SO 3 and NH 3. • Along the flow direction of flue gas in the air preheater, the deposited products will gradually convert from ABS to the mixture of ABS and H 2 SO 4. • ABS will convert into sulfate with higher decomposition temperature on fly ash. Ammonium bisulfate (ABS) aggravates the corrosion and plugging of air preheaters, resulting in unplanned outages and expensive cleaning. Understanding its deposition and transformation process is important for the development of ABS control strategies. A multistage temperature control system was built to simulate the temperature gradient in the air preheater and the deposition and transformation of ABS in the presence of fly ash were studied using Fourier-transform infrared spectroscopy, scanning electron microscopy, energy-dispersive X-ray spectroscopy, and thermogravimetry. The presence of fly ash increases both the deposition amount and the temperature of ABS in the 25–200 ppm SO 3 concentration range; the initial ABS deposition temperature is between 202 and 290 ℃ and most likely occurs in the 230–250 ℃ range. The main product was ABS, and its formation temperature was much higher than the deposition temperature observed in the experiment. In the 224–180 ℃ range, the products gradually changed from ABS to sulfuric droplets. Fly ash has trapping and adsorbing effects on the gas-phase ABS in flue gas, and more ABS is captured at high temperatures owing to the higher concentrations of reactants. ABS deposition leads to the accumulation and adhesion of fly ash particles and reacts with the fly ash to convert it into a variety of ammonium salts and sulfates with higher decomposition temperatures. Compared with the sulfate formed after the deposition of sulfuric acid droplets, the sulfate formed by ABS conversion had a lower relative decomposition temperature. [ABSTRACT FROM AUTHOR]

[Display omitted] • The performance and mechanism of CO 2 capture by amine blended solvents were reviewed. • The technology of simultaneous removal of CO 2 /NOx/SO 2 by ammonia was discussed. • The industrial challenges during CO 2 capture were summarized. • The specific directions have been proposed for the future development. Absorption/regeneration systems based on chemical solutions are considered a more appropriate option for post-combustion CO 2 capture, with amine solvents being the most commonly utilized. First, this paper provides a systematic review of the mechanisms and performance of CO 2 capture by blended solvents of amine–amine, amine-organic solutions, amine-inorganic solutions, and amine-ionic liquids. Furthermore, some process modifications that can reduce energy consumption and amine degradation during CO 2 capture are discussed. As a promising and challenging absorbent, aqueous ammonia shows potential for simultaneous removal of CO 2 /NOx/SO 2 , producing valuable byproducts like ammonium sulphate and ammonium nitrate fertilizers. Therefore, the current development of ammonia scrubbing techniques for CO 2 capture and simultaneous removal of CO 2 /NOx/SO 2 is subsequently reviewed in terms of reaction mechanisms, process modifications, and application challenges. Finally, specific directions have been proposed for the future development of amine and aqueous ammonia scrubbing techniques, which are expected to provide meaningful guidance for CO 2 capture by chemical absorption. [ABSTRACT FROM AUTHOR]