Infrared Drying: From Process Modeling to Advanced Process Control

Abstract

The article surveys the drying of solids materials and polymer solutions when infrared radiation (IR) is employed as the main heating source. The study reviews the current research trends of IR drying of specific applications. A case study similar to an industrial setting is presented to illustrate a model development and control scheme of an IR drying unit. The design and online implementation of an internal model controller (IMC) is discussed. The study demonstrates the controller capabilities to suppress random variations of the moisture content in the material entering the dryer. Simulation results also showed the success of model predictive control (MPC) multivariable controller ability, while handling process interactions and process constraints, to track setpoint changes in the humidity and temperature of the material exiting the dryer and to reject unmeasured stochastic disturbances in the inlet humidity stream. INTRODUCTIONEven though drying is an old and well-established process, the transport phenomena characterized by a simultaneous transfer of mass and energy is an interesting and fascinating area to study. In a recent survey, Mujumdar [1] reviewed the most important aspects of drying technology. He highlighted the R&D research trends in this area from conventional to new technologies. Energy saving and product quality are among the main concerns in industry today. Thermal drying, being defined as the removal of moisture from a solid, is one of the most ubiquitous and energy-intensive processes. Firstly, the energy required for a drying process can be supplied by different means to adapt the drying requirement of a variety of products and also to satisfy the industrial and market demand. Thus, efficient use and management of energy are very desirable in the design and operation of a drying unit. In fact, energy

Effect of Water on the Quality of Dehydrated Products: A Review of Novel Characterization Methods and Hybrid Drying Technologies

“…[144] Conventional freeze drying requires a long processing time. [145,146] The application of IR radiation in the freezedrying process significantly lowers the drying time [147] and improves the quality of dried products. The sweet potato and aloe vera were remarkably stable and had desirable sensory attributes when dried using IR-assisted freeze drying at the same time that the drying time was also WATER AND DEHYDRATED PRODUCT QUALITY significantly reduced.…”

Numerical modeling of physical fields in the process of drying of paper for corrugating by the infrared radiation

“…In (9) and hereinafter, the absorption coefficients of media are also effective values. For example, for a wet fluting this coefficient is determined by formula:…”

“…Thus, authors of [9] describe modeling the drying process by a radiation method. However, the model lacks the distribution law of IR radiation by thickness of the material.…”

“…This system includes (14), (15), a formal solution (9) for the boundary surfaces of the system and the current values of coordinate z [17].…”

A GODFIP Control Algorithm for an IRC Grain Dryer

“…Infrared radiation drying is a new drying technology developed in recent 30 years and now has become more popular because of its advantages, such as its low drying time, the reasonable quality of the final dried product, and its greater energy savings capability, in addition to its lower price compared to microwave and vacuum drying methods [3]. So far, the research scope of the infrared radiation drying technology mainly focuses on the study of experiments and simulation of drying, but there are no studies in the aspect of infrared radiation grain drying control [4][5][6][7][8][9][10][11]. In order to meet the drying control requirements of the IRC dryer, effective control strategies for the grain dryer should be further researched on.…”