Comparison between the Dual Pressure Low-Temperature Distillation Process and a Hybrid Natural Gas Purification Technology

Natural gas is the fastest growing fossil fuel in future global energy scenarios. The consequent increase in the global demand for it has led to the need for the exploitation of those reserves that were left undeveloped in the past because of the high CO2 content. Thus, new technologies have been recently proposed to treat the raw natural gas extracted from these reservoirs in a cost-effective and less energy-intensive way compared to conventional technologies.

The aim of this work is to analyze the Dual Pressure Low-Temperature distillation process recently developed by the GASP Group of Politecnico di Milano for this purpose. In particular, a comparison is carried out between this process and a hybrid technology, the SprexCO2 process, which combines a low-temperature distillation process for a bulk CO2 removal with chemical absorption into aqueous alkanolamines solutions. Simulations have been carried out with Aspen Plus® and the net equivalent methane method has been used to convert thermal and work fluxes of each process into the corresponding amount of methane required for their supply. Different CO2 contents in the raw natural gas feed stream have been considered in order to establish the breakeven point between the two processes.