Citgo Petroleum Corp., Houston, has taken final investment decision (FID) to move forward with its previously announced project to add a new unit intended to enhance processing of US domestic light crude and increase production of gasoline-blending components at its 479,000-b/d deep-conversion refinery along the Calcasieu Ship Channel in Lake Charles, La.

After announcing in mid-August its decision to defer funding for the now-formally named Lake Charles refinery depentanizer project (LCRDP), Citgo confirmed on Sept. 1 its approval of the LCRDP at a total investment of $310 million as part of the operator’s strategy to support long-term viability of the refinery, promote regional economic stability, and help ensure reliable US fuel supplies.

The LCRDP will involve the addition of new installations and equipment aimed at improving the St. Charles complex’s naphtha-upgrading capabilities by converting lower-value streams into higher-quality and higher-value gasoline blend components, Citgo said.

Alongside helping to improve long-term competitiveness of the refinery, Citgo said it expects the LCRDP will also increase refining flexibility at the site while enhancing the company’s ability to meet continued US demand for reliable transportation fuels.

Locally, the planned project investment will help reinforce a long-term future of the Lake Charles refinery to support ongoing employment for the complex’s existing Southwest Louisiana-based workforce, as well as create additional opportunities for contract workers, local suppliers, and service providers in the region during construction, the company said.

With formal FID on the project now in place, Citgo said it will advance engineering, construction, and commissioning activities to achieve targeted startup of a completed LCRDP in 2029.

The operator did not reveal a reason for its decision to bring forward funding for the project or whether the proposed investment would affect its most recent outlook for overall 2026 capital expenditures of $867 million in August that excluded LCRDP.

Originally commissioned in 1944, the St. Charles refining complex is now Citgo’s largest refinery following upgrades completed in 2023 that increased the site’s nameplate capacity to 463,000 b/d from 425,000 b/d, followed by subsequent improvements—including crude unit naphtha handling debottlenecking, process control upgrades, and other unidentified infrastructure enhancements—that collectively increased crude processing by another 16,000 b/d to its 479,000-b/d capacity, according to Citgo’s 2025 annual report.