抄録
Optimum operating condition of a single effect, vertical-long-tube type evaporator is presented in this paper. For such evaporator, the value of overall heat transfer coefficient has been given experimentally as a function of drum pressure, heating temperature, flow rate and density of solution.
Basic equations which describe the static properties of the evaporator are given by taking the mass and energy balances of solution, the material balance of solute, etc. into consideration.
From these equations, a polyhedron is formed to satisfy the constraints imposed on the variables such as condenser flow rate and circulation flow rate in three-dimensional space whose rectangular coordinate is heat consumption rate, drum pressure and density of solution respectively.
It is demonstrated that the optimum operating condition is determined by calculating the value of a performance index for each point in the polyhedron.
As a numerical example, optimum operating condition of a single effect evaporator for caustic soda is shown.
