EFFECT OF KEROSENE MASS FLOW RATE AND AVERAGE TEMPERATURE IN DIRECT CONTACT HEAT EXCHANGER

Abstract

Industrial plants are huge consumers of energy, these plants are installing heat exchangers in an effort to reduce energy consumption, and so improve operating efficiencies. Limited numbers of experimental and numerical investigations have dealt with the parameters affecting the heat transfer aspects in single phase direct contact heat exchangers which may be selected for their high thermal efficiency and minimum capital investment. In oil refineries energy from hot temperature oil streams can be recovered by transfer directly to a cheap coolant liquid in liquid-liquid direct contact heat exchangers. The heat recovered from these heat exchangers has different applications including preheating boiler feed water and preheating wash water. Heat recovery from hot temperature refinery products using direct contact heat exchanger throughout a theoretical phenomenological study is central to the theme of this paper. Kerosene-water system has been chosen. The effect of the heating fluid inlet temperature (65-97.50)°C, and mass flow rate (25 to 45) kg/s on direct contact heat exchanger design parameters and heat transfer characteristics were investigated theoretically throughout nine cases. Correlations of heat recovered from the system as well as design and operating characteristics of the heat exchanger were estimated. Increasing kerosene flow rate found to associate directly with increasing the contact surface area, number of plates, number of channels per pass and pressure drop, while when the heat exchanger is designed to operates at high kerosene inlet temperature, big heat exchangers with large areas, high number of plates and channels per pass are needed for efficient heat exchanger performance. Optimization and modeling the effect of kerosene operating variables on heat recovered was conducted using Response Surface Methodology. The results showed that an optimum heat recovery value of 6.8782 megawatt could be achieved for kerosene optimum inlet temperature (91.82°C), and mass flow rate (50.11 kg/s). Keywords: direct contact heat exchanger; kerosene and water system, kerosene mass flow rate and inlet temperature.