Comparison of the Mehra Process(sm) for Nitrogen Rejection to a Cryogenic Process for Nitrogen Rejection from Subquality Natural Gas. Topical Report, June 1990-April 1991

摘要

The objective of the study was to compare the technical merits and process economics of the Mehra Process for nitrogen rejection to a cryogenic process for nitrogen rejection from subquality natural gas. The Mehra technology is a solvent absorption process, while a cryogenic process employs low temperature partial condensation and fractionation to separate gases. The study consisted of preparing a complete nitrogen rejection process design for each technology, complete with a flow diagram, material and energy balances, equipment sizes, and utility consumptions. These data were inputted into a proprietary computer cost estimating program to calculate the total fixed capital investment and production costs for each process. For a 20 million scfd capacity nitrogen rejection system and at the same performance requirements for both processes, the Mehra technology was estimated to require 12% less total fixed capital investment than a state-of-the-art cryogenic process. The corresponding production cost savings by the Mehra technology were estimated to be equal to about 3 cent/million Btu of upgraded natural gas. Besides its favorable economics, the Mehra technology has many intangible technical attributes.