Conference article

In recent years; there has been great incentive to improve the energy utilization with which the existing capital in offshore and onshore surface facilities is utilized. One of the most energy intensive processes in oil upstream industry is natural gas liquid or NGL recovery plant. The main gorge of energy consumption in conventional NGL plants is propane refrigeration. Hence; more attention should be focused on the effective utilization of propane chillers in a NGL plant. In this study; a novel process configuration for recovery of natural gas liquids in NGL plant is purposed. The required refrigeration in this configuration is obtained by a selfrefrigeration system. In summary; the novel scheme generates refrigeration internally; decreasing cooling load of propane chiller and providing additional refrigeration for inlet gas cooling due to plant capacity increase. Besides; the recycled stripping gas also eliminates the need for external reboiler heat. The warmer the stripping gas; the less demand is placed upon the bottom reboiler; thereby saving fuel and energy cost. In this investigation; a simulation model has been developed on the basis of using novel configuration in Gachsaran NGL1200 in south of Iran. The model has been applied for evaluating of energy utilization in this plant. Results of the model show decreasing in total electricity demand of the plant from 268 kWh/tNGL to 175 kWh/tNGL by decreasing cooling load and electricity consumption in propane chiller. Also; the need for reboiler heat is satisfied and efficacy of demethanizer column is improved from 72% to 84% by more NGL recovery. Finally; economical analysis of the new retrofit has been studied.

NGL plant; self-refrigeration; SGR; energy utilization