“Renewable gasoline” from wood

A project to demonstrate an economically viable method for thermochemical conversion of woody biomass into gasoline is underway and gaining momentum. The first product has been produced and the results are promising. ANDRITZ and its partners are now ramping up to fine-tune the design for a commercial plant and to verify the economics.

From tree to pump. Jim Patel of Carbona (left) holds a sample of the woody biomass while Samy Ramzy Diab of Haldor Topsøe holds a sample of the renewable gasoline produced at GTI.

"The use of renewable gasoline would represent about a 92% reduction in life cycle greenhouse gas emissions when compared to conventional gasoline."
Jim Patel, President, Carbona

Editor’s note: We have been reporting on the progress of biomass-to-liquid development since UPM (the giant forest products company) announced its cooperation with ANDRITZ for the design and supply of a commercial-scale biomass gasification plant. The first story detailed the conceptual testing at the Gas Technology Institute (GTI) in the USA. The second story looked at UPM’s work in Finland with renewable diesel and talked of the testing at GTI with Haldor Topsøe’s syngas-to-gasoline process. This third report brings you up-to-speed on the exciting developments.

Note: The material in this story is based upon work supported by the U.S. Department of Energy, Golden Field Office, under Award Number DE-EE0002874.

"Developed nations are looking for alternatives to fossil fuels", says Petri Kukkonen, Vice President, Biofuels at UPM. Second-generation biofuels have the potential to be a big part of the solution. And," UPM can provide these biofuels while developing a profitable business in a fast-moving market". According to Kukkonen, the initial goal of the UPM-ANDRITZ work was to develop a technology platform that could be duplicated for multiple sites. "This development work was successful", he says. The initial testing at the Gas Technology Institute (GTI) in the USA was conducted on several different types of woody biomass. According to Kari Salo, Managing Director of Carbona, "We completed 10 test campaigns at GTI which enabled us to finalize the design of the plant. We fine-tuned our feed system, gasifier, gas conditioning, and gas cleaning. All the components were tested as a complete system, including the supervisory control."

New testing is proving out the integrated technology for producing a renewable gasoline from wood. Financing from the US Department of Energy (DOE) covers about 70% of the costs, with the partners sharing the rest. The overall goal of the DOE’s Integrated Biorefinery Program is to enable the production of biofuels and reduce the dependence on oil. A longer term (2022) goal set forth in the USA’s Energy Independence and Security Act is the production of 36 billion gallons per year of renewable transportation fuels. "This is a dream project", says Niels Udengaard, Syngas Technology Manager at Haldor Topsøe and the overall Project Manager for the tree-to-tank project. "All the individual technology steps – from wood supply to fuel station – have been demonstrated individually in the past. But, for the first time, they are now integrated into one plant to produce transportation fuel." Udengaard explains that the demonstration project is focused on achieving a production rate of about 20 barrels per day of renewable gasoline from wood biomass for 20 to 30 days. "This will give us enough experience to establish a design for a commercial plant which can produce 85 million gallons per year of ‘drop-in’ renewable gasoline. Drop-in means that no modifications are required to the infrastructure or the vehicles." According to Udengaard, about 95% of American automobiles are fuelled by gasoline. The scenario is different in Europe, where UPM is also involved in research for wood-to-diesel transportation fuels (using the Fischer-Tropsch synthesis process). For the demonstration, UPM provides the wood biomass, Carbona provides the technology to convert biomass to clean syngas, Haldor Topsøe provides the technology for processing syngas into gasoline, and Phillips 66 provides the emissions testing and fleet testing of the drop-in renewable gasoline (See box on page 7 for a brief profile of each company).

The project was kicked off in June 2010 when the process design was detailed and reviewed. The project makes use of proprietary technologies from Carbona (gasification), GTI/Uhde (acid gas removal), and Haldor Topsøe (gas purification and synthesis). The biomass is converted into renewable gasoline through the following steps at the Flex Fuel testing facility at GTI: gasification, gas cleaning/filtration, tar reforming, acid gas removal, and gasoline synthesis. One test bay at the facility accommodates the Carbona gasification, gas processing (reformer), gas conditioning (cooler), and cleaning (filtration and scrubbing) equipment. Another houses the Haldor Topsøe TIGAS unit.

In the gasification process , biomass is partially oxidized or partially combusted. The product of gasification is a combustible synthesis gas (or syngas). The Carbona bubbling fluidized bed gasifier is a high-pressure, oxygen- blown design capable of, in commercial size, up to 200 MWth biomass fuel input. Oxygen-blown syngas typically has two to three times the calorific value of air-blown. The gasifier is operated with a catalytic tar reforming system developed by Carbona and Haldor Topsøe to destroy and reform tars in the gas. "Compared to a boiler, the mixture in our gasifier is very fuel-rich, because the oxygen is controlled to avoid complete combustion," says Jim Patel, President of Carbona. Instead of producing CO2 and H2O, a gasifier produces mostly CO and H2. Our technology removes the heavy tars, cracks the lighter tars, reforms the methane, and reduces the ammonia content to produce a clean syngas.

"Gas cleaning is very critical," explains Richard Knight, GTI’s Project Manager . "The catalysts in the gasoline synthesis process are sensitive to contamination, so we are using our Morphysorb acid gas removal process prior to the Haldor Topsøe technology. Morphysorb was developed jointly between GTI and Uhde GmbH of Germany. It uses a nontoxic solvent created primarily from members of the morpholine chemical family to remove CO2 and H2S from the syngas."

The TIGAS process (Topsøe Integrated GAsoline Synthesis) is an improved version of the methanolto-gasoline process. Other technologies convert syngas into methanol, methanol into dimethyl ether (DME), and then DME into gasoline in a two-loop process. TIGAS streamlines that process by producing DME directly from the syngas in a single-loop process, eliminating the need for methanol production and storage. "TIGAS was developed in the 1980’s to convert natural gas to fuel", Udengaard says. "Today, we can use non-fossil resources as our raw material. We should be able to use any biomass in the future, perhaps even household waste." "Using these integrated processes, nearly 50% of the energy in the wood ends up in the gasoline, Patel says. That is a very high efficiency for the production of biofuels."

The work is being conducted at GTI in three test campaigns over a 29-month time frame. The first campaign, completed during March 2013, proved that the plant could be operated at steady-state to produce gasoline from woody biomass. The pilot plant’s capacity for feeding biomass is about 20 t/d. The biomass feed pellets are softer than standard fuel pellets and have about 10% moisture or less.

The wood source is primarily aspen from UPM’s forests, but the bark has been left on to simulate forest residue and mill wastes. During the first test, the front-end equipment responsible for producing the clean syngas operated very well and was on stand-by several days in readiness to provide syngas for the downstream processes, according to Knight of GTI. "The carbon conversion exceeded targets, gas cleanup was within limits, and the acid gas removal process was also within limits.

The TIGAS unit produced 96 octane gasoline, and the trace methanol in the wastewater was much lower than expected. After some initial mechanical issues, the TIGAS synthesis operated very well at steady reactor temperature profiles." "The results of the initial testing  were significant," Patel says. "We were able to establish stable operating conditions for steam-oxygen gasification and achieve high carbon conversion rates. Heavy tars were reduced in the reformer by up to 100%. The things we had to work on for the second test were to improve the reliability of the hot gas filter, to reduce the amount of nitrogen in the syngas, to integrate more tail gases to the gasifier, and to increase the yield," explains Patel.

The second campaign was recently completed with excellent results. The integrated plant operated for over 10 days and produced about 4,000 gallons (15,100 l) of good quality gasoline. The gasoline will be used to perform engine tests. The third campaign, to be completed by mid-2014, will apply the lessons learned to run steady-state for up to one month and produce sufficient gasoline for fleet testing. Based on success with this testing, a plant design capable of running steady-state at commercially attractive volumes and costs will be finalized. "By the end of the third test, we should have arrived at a commercial plant design that solves the current challenges, with all of the processes integrated and tested thoroughly," Udengaard says.
"Our project goals are energy efficiency above 45% and carbon efficiency above 32% (meaning the percentage of input energy and carbon content of the biomass converted into usable gasoline and LPG)." "these integrated processes, conversion of wood biomass to gasoline is energy efficient and one of the more attractive methods of producing renewable biofuels," says Patel. "The use of renewable gasoline would represent about a 92% reduction in life cycle greenhouse gas emissions when compared to conventional gasoline."

Carbona is an ANDRITZ subsidiary dedicated to gasification technology. It is supplying gasifier and gas cleanup technologies, including tar reforming.

Phillips 66 is an energy manufacturing and logistics company with midstream, chemicals, refining, marketing, and specialties businesses. The company has 13,500 employees and about US 51 billion in assets. It is providing the liquid fuel handling, transportation, single-engine emissions testing, and moderate fleet testing in preparation for registration with the US Environmental Protection Agency (EPA).

The Gas Technology Institute (GTI) is a leading research, development, and training institute that has been addressing energy and environmental challenges for more than 70 years. It has extensive experience with all types of gasification systems. It is providing the design, construction, and operation of the pilot plant as well as data analysis and data modeling.

Haldor Topsøe is a family-owned business founded in Denmark with about 2,200 employees worldwide. Its main activities are the manufacturing and sale of state-of-the-art catalyst and the licensing/engineering of catalytic processes. It is providing the TIGAS process, the technology for ultra-cleanup and conversion of the syngas, and overall project management.

UPM has 24,000 employees and is known as the Biofore Company. Its activities involve energy and pulp, papermaking, and the production of engineered materials. Its subsidiary in the USA is providing the biomass raw material (wood pellets).

SPECTRUM -   Andritz -  1/2014