Process Requirements and Enhanced Economics of Helium Recovery From Natural Gas

Abstract

Abstract The principal economic sources for the world's helium supply are helium rich natural gas reservoirs. Helium is found in natural gas reservoirs in concentrations ranging from 0.005% to about 8%. Typically, naturally occurring nitrogen also exists in these reservoirs. The presence of nitrogen requires processing of the gas to upgrade the heating value of the natural gas product stream. The helium recovery process can be thermally integrated into the natural gas processing operations of natural gas liquids (NGL) recovery and/or nitrogen rejection units (NRU). The helium recovery unit (HRU) can even be added as a straddle facility. The process requirements and the economic enhancement of helium recovery from natural gas for an NGL/NRU/HRU facility are presented. The facility process requirements covered include:–feed pretreatment for the removal of freezable components–turbo-expander process for NGL recovery–thermally integrated nitrogen rejection unit–thermally integrated helium recovery unit–feed gas and residue product compression Facility capital cost and economic evaluations are presented for example cases with and without helium recovery. A guideline is presented to illustrate how the addition of helium recovery can create economically attractive projects from otherwise marginal opportunities. Introduction The addition of helium recovery to natural gas processing can greatly enhance project economics. Depending on plant size and the helium content of the feed stream, helium can add to project revenues with minimal increases in capital and operating power. This can substantially boost a project's internal rate of return, making a marginal project look good, a good project look exceptional. The forecasted growth in helium demand coupled with the supply and demand picture, instills confidence in the economic opportunity for helium recovery. Helium is the second most abundant element in the universe, second only to hydrogen. Yet helium is rare on earth, found principally in only four regions of the world; the United States, Poland, Algeria, and the USSR. Helium is found in natural gas reservoirs ranging in concentrations from 0.005% to about 8%. P. 11^