Breaking Down the GTL Project at an Oklahoma Landfill

Final contracts have been signed to bring a joint venture gas-to-liquids (GTL) plant to the Waste Management East Oak Landfill site in Oklahoma City, Okla. These last contracts will cover the installation of process modules, related piping and ancillary equipment, for ENVIA's Oklahoma City GTL plant.

ENVIA Energy is the joint venture, between Houston-based Waste Management, Ventech Engineers International LLC, and Velocys, formed in March 2014 to produce renewable fuels and chemicals from biogas and natural gas using GTL.

Ventech Engineers International LLC designs and fabricates process modules for the oil and gas industry, with more than 350 modules, encompassing 25 different hydrocarbon processes, built in Ventech's Pasadena, Texas fabrication facility. Velocys, commercially based in Houston, Texas, deals with smaller scale GTL that turns natural gas or biomass into premium products such as diesel, jet fuel, waxes and base oils.

Fabrication of the modular process units by Ventech Engineers is essentially complete. The manufacture of Velocys' full-scale reactors and the initial catalyst charge to be used at the plant were completed in 2015. Mechanical completion of the GTL plant is expected in mid-year 2016.

Waste360 sat down with Dr. Neville Hargreaves, business development director for Velocys, to discuss the project.

Waste360: The ENVIA Energy GTL plant project is a partnership. Who are the partners and what are their roles?

Dr. Neville Hargreaves: ENVIA Energy is a joint venture, whose members include a subsidiary of Waste Management Inc., Ventech Engineers International LLC and Velocys. The JV is leveraging the expertise of the members in developing energy projects.

Waste Management is well positioned to use its expertise to identify and develop opportunities for the supply of landfill gas to projects developed by the JV. The Oklahoma City project is being situated adjacent to WM’s East Oak Landfill site. Waste Management has considerable expertise in landfill gas operations and the East Oak Landfill is the site of their WM GTL Inc. pilot scale landfill GTL unit constructed in 2009. The larger commercial reference plant currently under construction is being built at the same site because the permitting, gas flow, gas collection systems, operations, and finished product off-take and significantly landfill gas clean-up are well understood at that site.

Ventech is acting as EPC for the project. Its build of the projects’ modular process units at its fabrication facility in Pasadena, Texas, is essentially complete.

Velocys is providing the Fischer-Tropsch (FT) reactor and catalyst, utilizing its highly efficient microchannel technology and super-active catalyst—that enables gas-to-liquids (GTL) plants to be economical at the smaller scales needed at landfill sites. The manufacture of the reactors and initial catalyst charge for the project was completed in 2015. Following the announcement earlier in February Velocys is also taking a greater influence in the commissioning, start-up and operations of the plant.

Waste360: What technology will be used to convert landfill gas into liquid? How will it work?

Dr. Neville Hargreaves: The feedstock for the plant will be landfill gas co-fed with pipeline natural gas. The GTL process involves two main operations: the conversion of the gas into a mixture of carbon monoxide and hydrogen known as synthesis gas or syngas, followed by the Fischer-Tropsch process to convert the syngas into paraffinic hydrocarbons.

The products of the Fischer-Tropsch process can be upgraded to produce a wide range of high-quality finished products including ultra-clean diesel, kerosene, naphtha, bases for synthetic lubricants and waxes. The plant will deploy a number of Velocys’ full scale commercial Fischer-Tropsch reactors. The ENVIA Energy Oklahoma City GTL project provides a commercial reference plant for proving the use of smaller scale GTL with a combination of landfill gas or natural gas as feedstock and Velocys technology and Ventech engineering for that purpose.

GTL hasn’t been deployed commercially at a landfill site before now because smaller scale GTL technology, scalable for deployment at smaller gas resources is only now commercially available. Conventional GTL technology that has been successfully deployed to date by Shell and Sasol is only economical for plants producing 30,000 barrels per day or more. Only about 6 percent of the world's known natural gas fields—and none of the world’s landfill sites—are large enough to sustain a GTL plant of that size.

Scalable GTL is enabled by the combination of Velocys’ microchannel reactors and super-active catalysts that, together, significantly intensify the FT process, and Ventech’s modular construction methods. Plants can be easily scaled to match the size of the resource available, including at landfill sites.

Waste360: How will the liquid, or fuel, be used?

Dr. Neville Hargreaves: The final products of the process will be diesel, high value synthetic waxes, and naphtha. All of the product produced at the plant will be sold to third parties.

Fuels produced from the FT process offer significantly better performance than their petroleum-based equivalents. FT-derived diesel is highly paraffinic and does not contain aromatics or sulfur. FT fuels burn cleaner than petroleum-derived fuels, resulting in lower emissions of NOx, SOx and particulates. Use of high-purity FT diesel also reduces engine noise and reduces wear and tear on vital engine components. But most significantly, the GTL process can produce “drop in" fuels that are fully compatible with existing infrastructure and engines.

Because the feedstock for the ENVIA Energy Oklahoma City project includes a significant proportion of landfill gas—a renewable resource—the fuels produced by the plant deliver a significant reduction in lifecycle greenhouse gas emissions over their petroleum-derived equivalents.

 In general, synthetic waxes can be used for a wide variety of applications: candle making; coatings for waxed paper, cloth or tetrapak packaging; food-grade wax for e.g. coatings for hard cheese, sealants for jars cans and bottles; and in construction, tires, adhesives, polymers and personal care.

Speaking generally, uses for naphtha include as a chemical feedstock for ethylene crackers, to denaturate ethanol or as a blendstock for gasoline.

Waste360: What are the benefits of the system?

Dr. Neville Hargreaves: Smaller scale GTL, enabled by Velocys technology, provides a cost-effective way to take advantage of smaller scale and remote gas resources. Velocys' GTL technology makes smaller scale GTL possible due to the combination of our microchannel reactors and our super-active catalysts that together, intensify the FT process. This leads to better product yields and economics, and a plant that is easy to deploy at smaller scale.

Ventech’s modular construction methods can also bring considerable benefits to smaller scale GTL plants such as the OKC plant. The modules are constructed in an environmentally-controlled fabrication shop, where production can continue around the clock whatever the weather. Contrast this with stick-built conventional GTL plants that have to be constructed in the field. The efficiency and cost of labor in a factory environment is more favorable than in the field. Modular construction methods reduce the risks of schedule and cost overruns—an advantage not open to conventional GTL plants.

Waste360: What are the challenges?

Dr. Neville Hargreaves: At present the oil price is a challenge for oil industry projects or those producing products that are linked to the oil price. However, as a proportion of the products of this plant will be high valued specialty products, whose price is only weekly correlated to the oil price—and this helps mitigate the impact of lower oil prices, since high quality specialty products sell into a market that is predominately independent of crude. The U.S. EPA confirmed in 2015 that a portion of the products produced at the Oklahoma City plant will be eligible for cellulosic biofuel Renewable Identification Number (RIN) credits. This also helps with project economics.

Waste360: Any other uses for smaller-scale FT technology?

Dr. Neville Hargreaves: We consider this project to be a landmark for GTL and its application to landfill gas on a commercial basis. Another thing worth mentioning is that smaller-scale FT technology can also be used in conjunction with gasification of waste (avoiding landfill altogether); we’re involved in a number of prospective waste-to-liquids projects using that approach. Both of these routes are tremendously important for sustainable fuels. This is especially important for the airline industry, since there are so few alternatives for jet fuel—but this is one. And what better than to take a city’s waste, turn it into fuel and supply it to the local airport?