Calculation of electric energy savings and simulation of tank operation with variable extraction of steam and liquid phases of propane-butane mixtures

Abstract

Currently, when consumers use various categories of propane-butane mixtures of liquefied petroleum gas as the main or backup energy carrier, natural and artificial regasification systems based on electric or direct fire evaporators with intermediate heat transfer agent or solid-state intermediate heat transfer agent of various evaporation capacity, which operate depending on the design in various evaporation modes, are widely used. An important element for reducing energy consumption in the artificial liquefied petroleum gas regasification systems is the switching of tank to the combined regasification mode. The combined cycle provides two main periods of tank operation: the initial period with natural regasification of liquefied gas in the day tank, ground tube evaporator, and the subsequent period with artificial regasification of the propane-butane mixture in the evaporator with an intermediate heat transfer agent. For the purpose of theoretical justification of the proposed cycle, a mathematical model of combined regasification of liquefied petroleum gases was developed, which comprehensively takes into account the main periods of tank operation: with natural regasification mode in the day tank, ground heat exchanger and artificial regasification mode in the evaporator. The results of the conducted research show that the implementation of the combined regasification cycle in the liquefied gas supply can significantly reduce the energy costs of its evaporation, increases the energy efficiency of liquefied petroleum gas supply systems and provides an average annual savings of 33.7% in electric energy for regasification.