SoftOx for Stranded Gas Utilization: DOE STTR Phase I - Final Technical Report
Many of today’s oil producers are forced to flare associated natural gas or shut-in wells because they cannot economically bring their gas to market. Natural gas flaring and venting exposes pro-ducers to environmental liabilities, reduces their potential revenue, and depreciates their assets. This project is focused on a particularly acute problem for many oil producers—the co-production of sour gas that contains more than 1% H2S. In the absence of readily available centralized gas processing facilities or qualified re-injection wells, producers must either flare this sour gas or halt production. While addressing sour gas flaring is our initial focus, the proposed SoftOx gas-to-liquids conversion process is more broadly applicable to monetizing any natural gas resource that is currently economically stranded, flared, or vented. If successful, the SoftOx process could allow the monetization of over 5 Quads (5 EJ) per year of flared or vented natural gas worldwide, resulting in a reduction of up to 1% of global greenhouse gas emissions. The proposed SoftOx process is a proprietary thermocatalytic process that converts hydrogen sul-fide and methane into sulfur-containing liquid hydrocarbon compounds and sweetened hydrogen-rich natural gas. The novelty of this process lies in the use of sulfur to oxidize methane (soft oxidation)—instead of oxygen—allowing it to overcome fundamental challenges associated with oxygen-based methane conversion to liquids—that is, the thermodynamically favorable conversion of methane to carbon dioxide and the high cost of separating oxygen from air. Moreover, the simplicity of the proposed two-stage thermocatalytic process allows for the economical production of small modular process units that can address the relatively low volumes of flared and vented natural gas (< 100 Mscfd), as compared to traditional sour gas treatment (amine/Claus) and gas-to-liquid (Fischer-Tropsch) processes that require massive scale (> 10,000 Mscfd) to be economical. In this DOE STTR Phase I project, we demonstrated a bench scale (~ 20 scfd) integrated SoftOx process comprising two consecutive reactors and a membrane separator with single-pass yields to liquid products of 11–13 wt% using simulated sour gas feed (70% CH4, 20% C2H6, 5% C3H8, 5% H2S by volume). We also developed an optimized process model and conducted a detailed technoeconomic analysis of a 90-Mcfd SoftOx process unit with a baseline simple payback period of 5 years and a 2-year payback at high levels of deployment of 50 units or more.
- Research Organization:
- Modular Chemical Inc.
- Sponsoring Organization:
- USDOE Office of Science (SC)
- Contributing Organization:
- Modular Chemical Inc., Gas Technology Institute, AristoSys LLC
- DOE Contract Number:
- SC0019805
- OSTI ID:
- 1797701
- Type / Phase:
- STTR (Phase I)
- Report Number(s):
- ISRN MCI/DOE/TR-2021-FINAL
- Resource Relation:
- Related Information: n/a
- Country of Publication:
- United States
- Language:
- English
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