Numerical method for predicting heat and mass transfer law of tobacco shreds in drum dryer

Abstract

The invention discloses a numerical method for predicting the heat and mass transfer law of tobacco shreds in a drum dryer. The drum cut-tobacco dryer is axially divided into a plurality of equidistant micro-units, and a mathematical model of heat and mass transfer is established for tobacco shreds and air flow in each micro-unit. Based on mass conservation equation, energy conservation equation and heat-mass balance equation, the program is solved by computer language. The residence time involved in the mathematical model of heat and mass transfer of tobacco shreds was calculated by the motion model of tobacco shreds and the modified empirical formula. The effective heat transfer coefficient and mass transfer coefficient of tobacco under different temperature and moisture content were measured by experiment method, and the database was established. The data of the database was directly transferred into the program when calculating the temperature and moisture content of tobacco alongthe drum dryer axis. Finally, the operating parameters of the production process can be inputted into the simulation system to obtain the tobacco outlet temperature, moisture content and the drum dryer along the axial temperature and moisture content curves.

Description

technical field [0001] The invention relates to the fields of chemical industry and tobacco, in particular to a method for measuring the law of heat and mass transfer of shredded tobacco in a drum shred dryer. Background technique [0002] Drying is a process with a long history, and its main purpose is to remove moisture from materials for storage, transportation and improvement of product quality. In the cigarette process, shredded tobacco drying is a key process in the shredded process. The heat and mass exchange characteristics of shredded tobacco are directly related to the whole process of being dried or rehydrated, thus affecting the moisture content of the particles themselves, the filling capacity of shredded tobacco, the crushing rate of the rolling process, and the sensory quality of finished cigarettes, which are closely related to the final quality of cigarette products. Economic benefits are closely related. In the production process of shredded tobacco, the ...

AI Technical Summary

Problems solved by technology

At present, in the cigarette production process, the optimal operating parameters are often obtained by on-site debugging of operating parameters and multiple tests. However, the moisture content and temperature data of shredded tobacco in the drum during the drying process are not easy to measure, and traditional experimental methods will Encountered obstacles such as heavy workload, high cost, long cycle time, and high energy consumption, the production process level still remains at the stage of relying on experience, which is not conducive to the improvement of the quality of shredded tobacco, and at the same time, the advantages of the shredded shredded machine cannot be brought into play

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