Engineering: How Much Energy Does It Take to Cook Cereals II?
In this column, Levine continues the calculations begun in his column published in the January-February 2013 issue of CFW to determine the energy used to cook cereal grains. With a goal of reaching a moisture content of 33%, calculations to approximate steam condensation in the drum are presented. Because steam condensation is the result of heat lost to the environment, performing this calculation requires the estimation of the heat transfer coefficient and surface area of the drum. The resulting moisture content still falls short and, therefore, requires the addition of water. Calculating the amount of water that must be added to the drum requires an equation for a mass balance and heat balance that can be solved to obtain the added water requirement. The process also requires the use of steam to remove air from the vessel. The amount of purging required can be calculated by figuring that 99% of the air volume in the vessel must be removed and considering the order of decay and the density of the steam at process pressure.