Abengoa Cellulosic Ethanol Biorefinery, Kansas, United States of America

Spanish sustainable technology company Abengoa Bioenergy (Abengoa) officially opened its commercial scale integrated biorefinery for the production of ethanol from lignocellulosic biomass in Hugoton in Kansas, US, in October 2014. The facility is owned and operated by Abengoa Bioenergy Biomass of Kansas (ABBK), a wholly owned subsidiary of Abengoa.

The $685m biorefinery has a capacity to produce approximately 25 million gallons of cellulosic ethanol per annum. It will reduce about 139,000t of carbon dioxide emissions a year resulting from burning of 15.5 million gallons of gasoline fuel for automotive transportation. It will be equivalent to removing 35,000 cars from road. It will also reduce oil imports.

The plant co-generates 21MW of electricity for captive consumption, while the excess power is supplied to the local Stevens County community. Lignin and animal feed are produced as by-products.

Work on the facility was started in July 2011. Construction was officially started after receiving the prevention of significant deterioration (PSD) air quality construction permit from the state in September 2011. It was completed in mid-August 2014 and production of cellulosic ethanol began at the end of September 2014.

Feedstock used at Abengoa's biorefinery

The biorefinery utilises multicellulosic biomass, crop residue and plant fibres as feedstock. Up to 80% of the feedstock consisting of irrigated corn stover, and the remainder comprises wheat straw, milo stubble and switchgrass.

The cellulosic biomass requirement of the plant is approximately 350,000t a year. ABBK has secured the supplies from the local biomass producers for ten years. The feedstock is sourced within 80km distance from the plant.

Background to the bioethanol project

"The facility is owned and operated by Abengoa Bioenergy Biomass of Kansas (ABBK), a wholly owned subsidiary of Abengoa."

Plans to construct a commercial scale second generation (2G) biorefinery at Hugoton were initiated in 2007. The Hugoton site was selected for abundance of feedstock and support from the state. The US Department of Energy (DOE) guaranteed a loan of $132.4m from the Federal Financing Bank in August 2011, including a $97m grant for the project.

Abengoa's facility is one of the six second-generation bioethanol facilities supported by the DOE in the US. The US Department of Agriculture also supported the project under the Biomass Crop Assistance Program.

The project will benefit the local economy by paying $17m for every 1,000t/day of feedstock, creating 300 local construction jobs for two years and contributing $9m towards purchase of local services, goods and supplies every year. The plant also employs 65 permanent staff at an estimated annual payroll of $5m.

Plant details and technology used at the Kansas complex

The biorefinery sits on a 385-acre site in Stevens County and includes complex buildings, plant wide utilities and product storage facilities. It is located next to 425 acres of agricultural land, which serves as buffer.

The ethanol conversion process at the plant is based on a proprietary enzymatic hydrolysis technology developed by Abengoa. The proprietary fractionation technology and catalysts were developed at the research and development laboratories in Seville and Babilafuente and at the Seville University biochemical laboratory. The custom-made enzymes were developed with licence from Dyadic International, based on the patented C1 Technology Platform.

It was tested, evaluated and verified for over ten years before it was applied. The company has been operating a 0.4Ml/y pilot facility in York, the US, since 2007. A 5Ml/y demonstration scale facility has also been operational in Babilafuente in Salamanca, Spain, since September 2009.

Processing at Abengoa Bioenergy's Stevens County-based biorefinery

The ethanol conversion process involves preparation of the biomass feedstock for pre-treatment.

"The $685m biorefinery has a production capacity of about 25 million gallons of cellulosic ethanol per annum."

Enzymes are added to enhance the pre-treatment conditions for further thermochemical reactions. Enzymatic hydrolysis converts the cellulose of agricultural residues to glucose and xylose sugars. These sugars are fermented and distilled to produce renewable cellulosic ethanol fuel. The remaining solution undergoes stillage for separation of wastewater and recovery of about 29,000t/y of lignin.

The unconverted biomass and crop residual wastes are used as fuel in the biomass boiler to produce high pressure steam, generating electricity and heat through the turbine and generator units.

An estimated 1,200t of agricultural residue is processed at the facility each day to generate the fuel and green power. The unconverted residual solids, other agricultural biomass and biogas from anaerobic wastewater treatment are used to generate heat and electricity.

Contractors invovled in the Hugoton-based bioethanol plant

A consortium of Abener Engineering and Construction Services and Teyma USA served as the project engineer and design-build contractor. Partnered companies included Abengoa Bioenergy New Technologies and Abengoa Bioenergy Trading.

Pioneer Electric Cooperative is the retail electric service provider for the facility.

NRI Energy Technology