In a patent application published 1 December 2015, Altex described the basic approach for its synthetic fuels processes. Carbonaceous materials—e.g., coal, biomass, or waste—is heated in the absence of molecular oxygen to produce a solid containing char and ash and volatile gases. However, in contrast to other processes which partially condense the volatile gases to form pyrolysis oil, in the Altex system, the volatile gases are fed directly to a second non-catalytic reactor.

This reactor converts a portion of the volatile gases into a mixture of light olefins, predominantly ethylene and propylene. This process, like gasification in the gasification/F-T processes, effectively normalizes the volatile gas feed by converting it into a gas stream that is relatively independent of the feed composition.

The stream now containing light olefins, which are reactive towards oligomerization using very inexpensive catalysts, are optionally first cleaned using standard gas-cleanup techniques and then fed to a third reactor where they are linked together to produce hydrocarbons of the correct molecular weight for the targeted synthetic fuel.

This use of light olefins as building blocks results in good control of the product composition as with a traditional gasification/F-T process. It also reduces cost by avoiding the need for hot-gas cleanup and F-T catalysts.

In contrast to traditional pyrolysis, the main product can be used as a high-value liquid fuel. By combining inexpensive feedstock and the best aspects of pyrolysis processes (e.g., lower cost) and gasification/F-T processes (e.g., finer product control) with oligomerization of the light olefins produced, the process embodiments of the invention enable the production of synthetic fuel from carbonaceous material at a relatively low cost.

—US 9199889

Altex has been working with the US Department of Energy (DOE) on developing a version of the process to convert a mixture of coal and biomass to jet fuel since 2012. The company has made consistent progress on the Coal-and-Biomass-to-Liquids (CBTL) System and received a second DOE project to further develop this technology, referred to as the GreenHouse Gas Reduced Coal and Biomass to Liquid Based Jet Fuel (GHGR-CBTL) System. This award scales up the CBTL capacity, from the existing .3-BPD to 1-BPD, and increases the technology readiness level (TRL) from 4 to 5.

Altex is using the equipment developed, data gathered, and experience gained through the DOE efforts for the biomass to synthetic gasoline project with the Energy Commission.

Data generated by this pilot plant, that will be located in Sunnyvale, California, will enable us to design a commercial plant to make 3,000 BPD of ASTM Standard D4814 gasoline at a cost of less than $2 per gallon. In order to support California’s aggressive objectives regarding greenhouse gas emissions, we intend to achieve a climate change related carbon intensity of 30 g CO₂e/MJ, that will be 65% less than petroleum based gasoline.

—Dr. Mehdi Namazian, Vice President of Altex

Much of the work that Altex has conducted to date on this technology has been supported by the US Department of Energy, the Defense Advanced Research Projects Agency (DARPA) and the US Army.

Unitel is a designer and builder of modular pilot and mini-plants. Over the years, the Unitel team has executed more than 1,300 projects, many of them first-of-a-kind, for 400+ major industrial firms and R&D organizations in 35 countries.

Our most recent successful biomass project involves the design and construction of a recirculating fluid catalyst demo plant for RTI International. The pyrolysis oil made by this unit is converted into oxygen-free fuels using a two-reactor hydrotreating pilot plant that was also designed and built by Unitel.

—Serge Randhava, CEO of Unitel

Resources

• Method and apparatus for conversion of carbonaceous materials to liquid fuel US 9199889 B2