Field Analytical Method Development for C6-C9 Ranged Hydrocarbon Measurement

Oral Presentation

Prepared by D. Kong1, T. Vidra2, H. Muhammad2, K. Sutrisno2, B. Morlan1, R. Kamath1, S. Mcmillen1
1 - Chevron Engergy Technology Company, 100 Chevron Way, 50-1263, Richmond, California, 94802, United States
2 - Chevron Pacific Indonesia, , , United States


Contact Information: kitty.kong@chevron.com; 510-2421654


ABSTRACT

Scope/Objectives: Total Petroleum Hydrocarbons (TPH) in soil is often measured to determine if soils have been impacted by crude oil. Chevron Pacific Indonesia (CPI) operates several oil fields in Sumatra, and during site decommissioning, TPH values of soil samples must be analyzed. In 2014, a new regulatory requirement to test for C6-C9 ranged hydrocarbons was issued by an Indonesian government agency. In most of the aged crude oil contaminated sites, the concentration of volatile petroleum hydrocarbons in the C6-C9 range is very low or below detection limits.
Methods and Results: CPI conducted lab and field studies using commercially available portable GC-MS (Gas Chromatography with Mass Spectrometry) and solid phase micro extraction (SPME) to measure the C6-C9 ranged hydrocarbons. Portable GC-MS have been used widely for BTEX (Benzene, Toluene, Ethyl Benzene and Xylene) and other volatile organics measurements, but it has not been reported to test for TPHg ranged material measurements. Proof of concept work targeted to the total concentration of C6-C9 ranged hydrocarbons started in 2016 and quickly moved into pilot testing on-site in 2017. Over 250 freshly collected soil samples were tested using a portable GC-MS over a period of ten days. The field results for over 10 % of the samples were compared to the EPA 8260 TPHg performed by a third party commercial lab. The results demonstrated that the conventional EPA 8260 method using solvent extraction or the time-consuming purge-and-trap technique, and the prescribed sample preservation with methanol can all be avoided to produce acceptable screening results for quick analysis using a portable GC-MS with SPME. Of the 250 samples analyzed, none contained TPHg C6-9 above regulatory limits.
Novelty: This pilot study is the first to report the TPHg measurement using a portable GC-MS, to provide a quick screening for which soils may require remediation.
Keywords:
Rapid field analytical method, Portable GCMS, Solid Phase Micro Extraction, total petroleum hydrocarbons (TPH) and soil sample