In Silico Modeling of a Novel Refrigeration Process of the Ammonia–Water Falling-Film Absorption

Abstract

Nowadays, the ammonia–water absorption refrigeration system (AARS) has attracted much attention due to its merits such as energy conservation and environment-friendliness. Meanwhile, growing studies have focused on the key equipment of ammonia–water absorber of AARS. Based on the thermodynamic and transfer property models that are specially determined in this study for the ammonia–water system, a calculational model of the ammonia–water falling-film absorber outside vertical tubes (AW-FFA-OVT) is established. The simulation of the ammonia absorption process is then carried out by the Fortran program in silico. The reliability of the physical models and the absorber model is verified by comparing with the experimental data from the literature. The mechanism of the proposed ammonia absorber is investigated by observing various key factors. The proposed model has already been successfully applied in the design and simulation of the key equipment in an actual AARS process.

Efficient Synthesis of α-FeOOH from Pickling Wastewater in Falling Film Tower and Its Kinetics

“…The red line in the figure is the circulation path of the reaction solution, and the blue line is the circulation path of insulated water. The falling film tower has attracted extensive attention due to its characteristics of small temperature difference and high mass transfer efficiency. , In addition, there are no moving parts inside; the structure is simple and not easy to block, thus avoiding the shortcomings of the packed tower, such as large gas–liquid resistance and gas–liquid interception. , At present, there are few studies on the synthesis kinetics of α-FeOOH and even less on the macrokinetics considering the influence of mass transfer. Domingo et al studied the oxidation kinetics of different iron oxides.…”

“…The falling film tower has attracted extensive attention due to its characteristics of small temperature difference and high mass transfer efficiency. 14,15 In addition, there are no moving parts inside; the structure is simple and not easy to block, 16 such as large gas−liquid resistance and gas−liquid interception. 17,18 At present, there are few studies on the synthesis kinetics of α-FeOOH and even less on the macrokinetics considering the influence of mass transfer.…”

Process Simulation and Optimization of Ammonia-Containing Gas Separation and Ammonia Recovery with Ionic Liquids

“…Meanwhile, NH 3 is also an important chemical raw material, which can be used as refrigerants and nitrogen fertilizer. 4,5 Therefore, the cleaning treatment of NH 3 separation and recovery from industrial gases is considered as a significant and essential technology to reduce atmospheric pollution and increase the efficient utilization of NH 3 .…”

“…Considering the fact that NH 3 is able to form ammonium salt with NOx and SO 2 in the atmosphere, it is also a major source of particulate matter 2.5 (PM 2.5) pollution. , Thus, NH 3 emission regulation becomes more and more urgent in recent years. Meanwhile, NH 3 is also an important chemical raw material, which can be used as refrigerants and nitrogen fertilizer. , Therefore, the cleaning treatment of NH 3 separation and recovery from industrial gases is considered as a significant and essential technology to reduce atmospheric pollution and increase the efficient utilization of NH 3 .…”

“…Several operational parameters are optimized for the ammoniacontaining tail gas purification process, such as the number of total theoretical stage (N stage ), feed stage of semilean liquid (N solvent ), the ratio of splitted lean liquid to the total liquid flow rate (R SLT ), total absorbent flow ratio (F total ), absorption pressure (P ab ), pressure of flash 1 (P flash1 ), pressure of flash 2 (P flash2 ), and temperature of flash 1 (T flash2 ). The value ranges are [6,20] for N stage , [4,18] for N solvent , [0.2, 0.8] for R SLT , [5,40] The optimization of the purification process is shown in the following equation. The objective functions are the minimum of TPC and TPCOE and maximum of η eff .…”