Ra Ximhai (Jul 2017)
METHODOLOGY FOR ESTIMATION OF STATIONARY AND DYNAMIC PARAMETERS FOR LIQUEFIED PETROLEUM GAS (LPG) RE-LIQUEFACTION IN SPHERICAL STORAGE SYSTEMS
Abstract
Temperature difference between the environment and the liquid contained in the liquefied petroleum gas storage spheres produces: net inward heat flow, increase in stored fuel temperature, LPG partial vaporization and consequently an increase in storage pressure. In order to maintain adequate safety conditions, since uncontrolled pressure increases could lead to risky situations and economic losses, re-liquefaction systems, consisting on auto refrigeration units, are installed; this system extracts the evaporated gas, compress it and then condense it again in a closed cooling cycle. Frequently these systems are designed using heuristic criteria, without considering the calculations necessary for correct equipment sizing; this results in costly modifications or in oversized equipment. In the present article, a simple but effective methodology for the calculation of thermal loads, daily temperature increase rate and pressure accumulation and restore times is presented, the methodology was compared with real data, through data acquisition and processing during the summer months of 2015 and 2016 for 12 storage spheres in a gas company located in a coastal state of Mexico, finding that the values predicted for the rate of daily temperature increase and recovery times are statistically consistent with the experimental data.
