Analysis of trace organics and its correlation with COD in condensate from natural gas to hydrogen production

Qualitative and quantitative analysis of trace organics in the condensate and its correlation with chemical oxygen demand (COD) is the key to the research on the reuse technology of condensate (condensate) from natural gas to hydrogen production process. The contents of anions, COD, total organic carbon (TOC) and total nitrogen (TN) were measured by ion chromatography and the TOC analyzer. Trace organics in the condensate and its correlation with COD was investigated in this paper. Results show that the contents of COD and TOC is 74.1 and 17.81 mg/L, respectively, and the anions in the condensate are mainly Cl-, I-, and SO42-, etc. The condensate mainly contains small molecule organics including methanol, ethanol and formic acid with the content of 41.4, 2.1 and 3.2 mg/L, respectively. The spiked recovery of methanol, ethanol and formic acid is 96.1%, 100.2% and 103.9% by high performance liquid chromatography (HPLC) and gas chromatography (GC), respectively. Methanol is the main source of COD in the condensate, and the contribution rate reaches up to 83.8%. The removal of trace methanol can significantly reduce the COD of the condensate. This work might provide basic data for reasonable recovery and utilization of condensate in the hydrogen production process.