Key indexes evaluation of the domestic largest helium extraction unit for single well with normal temperature process

Objective The largest helium extraction unit for a single well using a normal-temperature process in China, this unit uses process of two-stage membrane separation coupled with two-stage pressure swing adsorption. Performance evaluation of this unit can provide critical operational data for domestic helium-poor natural gas helium extraction technology development. The use of a simple orifice flowmeter poses significant challenges to the evaluation of key performance indexes.

Method Based on the material balance of helium and carbon dioxide, this study developed: Firstly, a calculation method for estimating feed gas flow rate using measurable gas component data. Secondly, the calculation formulas of helium yield in the first-stage membrane separation and the helium loss rate in the first-stage pressure swing adsorption without flow data.

Result Firstly, the product gas component significantly exceeded the design specifications: φ₂（He）=98.50%, φ₂（H₂）=1.50%, φ₂（CH₄）=1.14×10⁻⁶, φ₂（CO₂）＜0.10×10⁻⁶. Secondly, the key performance indexes surpassed design expectations: the total helium yield of the unit was 82.25%, the helium yield of the first-stage membrane separation was 93.21%, and the helium loss rate of the first-stage pressure swing adsorption was 0.17%.

Conclusion The proposed evaluation methodology effectively resolves the performance evaluation challenges caused by orifice plate flowmeter measurement errors, establishing a reliable framework for single-well helium extraction unit performance evaluation. The outstanding operational performance of the unit demonstrates the industrial application feasibility of this membrane separation coupled with pressure swing adsorption process.