# Parametric Analysis of Cylinder Drying Process in Association with Various Materials
## 1 Introduction  
Drying is one of the indispensable steps in many industrial manufacturing processes, such as chemical and pharmaceutical industries, agriculture and food processing, pulp and paper production, wood and minerals processing, solid fuels preparation, etc. [1]. More importantly, the drying process requires a vast amount of energy [2]; this directly impacts the near-future energy shortage and fast global warming. Aiming at gaining better insights into the drying process and reducing the energy consumption as well as decreasing the hazards of drying materials, many researchers were involved in studies of this field. In which, [PERSON] et al. [3] examined the drying rate of fabrics. In their study, the drying rate is defined by the weight of water evaporating per unit area per unit time. Their results indicated that most fabrics have the same drying rate; however, the drying time of fabrics not only depends on the drying rate but also depends on the amount of water, which the fabric is holding before drying; therefore, some fabrics can dry sooner than others are. A handbook of industrial drying was introduced by [PERSON] [4]. In this handbook, various drying methods for many different materials and different drying processes are presented in detail. The drying of porous material was investigated by [PERSON] et al. [5]. They revealed that in the falling rate period, the drying rate is slower than that of the constant rate period. In the third stage of the falling rate, the moisture contained within the subsurface is continuously evaporated until it is in equilibrium with the ambient environment. [PERSON] et al. [6] developed a mathematical model for optimizing the energy consumption in a single-tier cylinder dryer. They reported that the single-tier cylinder dryer could savethe steam supply up to 4.6%. [PERSON] [7] proposed a new model of multi-cylinder dryers for a paper drying process. In their study, the moisture and temperature of the drying materials, as well as the energy consumption of the drying system, were examined in detail. Fundamental theory and applications of paper drying were introduced by [PERSON] [8]. In the book, he suggested applying the anti-blow boxes and vacuum rolls in the drying system for decreasing energy consumption. [PERSON] and [PERSON] [9] developed a static energy model to describe the conventional drying process of a multi-cylinder paper dryer. They employed the specific drying rate, specific heat consumption, and energy efficiency to evaluate the performance of the drying process. Transient heat-and-mass transfers in a cylinder dryer were investigated by [PERSON] and [PERSON] [10]. In their study, a computational model was developed to calculate the heat-and-mass transfer processes in the dryer system, and experiments of a single-cylinder dryer were also carried out to verify the numerical results. Although the computational model was developed for examining the heat-and-mass transfer of the paper drying process, they suggested that the computational model could also be applied to predict the drying process of other materials. Concerning the computational model developed by [PERSON] and [PERSON], [PERSON] [4] commented that the term for containing moving materials (V is the velocity), which was employed in the theory of [PERSON] and [PERSON], can be neglected due to the extremely high rotational speed of the cylinders. Investigations of the hybrid drying of food and bioproducts were reviewed by [PERSON] et al. [11]. They pointed out that the drying kinetics and efficiency as well as the product quality are significantly influenced by the rate of moisture removal. The reaction engineering approach was proposed and applied by [PERSON] and [PERSON] [12; 13; 14]. They revealed that their proposed model could effectively predict the temperature during the composing of sewage sludge compared to that of the experimental results. The reaction engineering approach was also reported by [PERSON] et al. [15] and [PERSON] et al. [16].