Drying process evaluation

Simultaneous heat and mass transfer also occurs in drying processes, chemical reaction steps, evaporation, crystallisation, and distillation. In all of these operations transfer rates are usually fixed empirically. The process can be evaluated using either the heat- or mass-transfer equations. However, if the process mechanism is to be fully understood, both the heat and mass transfer must be described. Where that has been done, improvements in the engineering of the process usually result (see Process energy conservation). 

Higgins, G. M. Helmstetter, A. J. "Evaluation of Hazardous Waste Incineration in a Dry Process Cement Kiln," Proc. 8th Annu. Res. Symp. Incineration and Treatment of Hazardous Waste, EPA-600/9-83-003, 1983. 

Once the baseline data for heat distribution are established, the combination of in-process moisture analysis (of the load being dried) and heat or airflow distribution (for a loaded oven) will help the technologist understand the drying process for a product. In addition, other information learned will include the moisture level in the dried granulation can be reached without exposing the material to excess heat. This relationship will help QA evaluate the process during validation as well as audit the process if process deviations should be encountered. 

Leovic, K.W., Whitaker, D.A., Northeim C. and Sheldon L.S. (1998) Evaluation of test method for measuring indoor air emissions from dry-process photocopiers. Journal of Air sj Waste Management Association, 48, 915-23. 

Damaged Books and Evaluation of Traditional and New Drying Processes, Adv. Chem. Ser. (1977) 164,105. 

An instrument performing measurements of D2 (viz. the ratio of the resistivity of ice to that of a product at a given temperature) and implementing DTA (differential thermal analysis) was developed to control freeze-drying processes the principal components are a test chamber, a cooling and heating unit, a digital computer system and a printer. It was used to evaluate the thermal features of a 20% sucrose solution [12]. 

The most likely syngas consumers in the infrastructure are Fisher-Tropsch diesel processes, ammonia producers, methanol producers and the Direct Reduction of Iron (DRI) process. The H2/CO ratios required by these process range from >0.68. 4. Assuming that syngas is produced using entrained flow reactors with reformers, preliminary economic evaluation revealed that the HQ pipeline should provide syngas in a ratio bandwidth of 0.9-1.1. 

The effect of mixtures on the detachment conditions was also evaluated by dr)dng pastes made by a mixture of maltodextrin MOR-REX 1910 and sucrose, with a total solid content of 61.5%, but with increasing amount of sucrose (5, 10, and 15% sucrose, dry weight basis (dwb)). Results in Figure 21.3 indicate that for a defined drying temperature, the moisture content at the moment of self-detachment of the dried film decreased with the increase in sucrose addition. Thus the addition of sucrose made the detachment of dried films of maltodextrin from an inert solid surface during the drying process more difficult. The larger the amount of sucrose added. 

Pakowski, Z., Bartczak, Z., Strumillo, C., and Strenstrom, S. 1991. Evaluation of equations approximating thermodynamic and transport properties of water, steam and air for use in CAD of drying processes. Drying Technology—An International Journal 9 753-773. 

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