Abstract A theoretical model of the absorption of soluble gases during the first stage of slurry droplet drying, at or below room temperature and at atmospheric pressure, is suggested as a basis for the development of alternative drying methods. The suggested approach is based on the theory of slurry droplet evaporation, in conjunction with a model of chemical absorption by evaporating droplets. Slurry droplet evaporation is described by a system of transient conjugate nonlinear energy and mass conservation equations. Numerical calculations are performed for a slurry droplet evaporating in various gaseous mixtures, including a gaseous mixture containing soluble gases. It is shown that the effect of gas absorption is a significant enhancement in the rate of evaporation of a slurry droplet, with higher concentrations of soluble gas in the gas phase leading to a shorter first stage of drying. In particular, in a ternary gaseous mixture (N2/NH3/H2O) with an ammonia mass fraction of 0.5 and at 288 K, the evaporation time of a coal-water slurry droplet with an initial radius of 100 was about 20% shorter than that in a mixture free of soluble gases. The existence of a maximum in the temporal dependence of the interfacial temperature of the droplet during evaporation is also revealed. This maximum becomes more pronounced with increasing ambient concentration of the absorbate. Calculations show that relative humidity exerts a minor influence on the dynamics of gas absorption by liquid droplets. By contrast, relative humidity strongly affects the rate of evaporation of slurry droplets. The model for slurry droplet evaporation in the presence of soluble gas presented herein allows for calculation of the appropriate concentration of soluble gas in the gaseous phase to achieve an optimal regime for slurry droplet drying.

中文翻译：

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化学解离反应吸气对单浆液滴干燥的影响

摘要 建议在室温或低于室温和大气压下浆液滴干燥的第一阶段吸收可溶性气体的理论模型作为开发替代干燥方法的基础。建议的方法基于浆液液滴蒸发理论，并结合蒸发液滴的化学吸收模型。泥浆液滴蒸发由瞬态共轭非线性能量和质量守恒方程系统描述。对在各种气体混合物中蒸发的浆料液滴进行数值计算，包括含有可溶气体的气体混合物。结果表明，气体吸收的影响是浆滴蒸发速率的显着提高，气相中可溶性气体浓度较高，导致第一阶段干燥时间较短。特别是在氨质量分数为 0.5 和 288 K 的三元气体混合物 (N2/NH3/H2O) 中，初始半径为 100 的水煤浆液滴的蒸发时间比其短约 20%。在不含可溶性气体的混合物中。还揭示了蒸发过程中液滴界面温度随时间变化的最大值的存在。随着吸收物的环境浓度增加，该最大值变得更加明显。计算表明，相对湿度对液滴吸收气体的动力学影响很小。相比之下，相对湿度会强烈影响浆料液滴的蒸发速率。