Bio-SNG (Synthetic Natural Gas) and Gasification Technologies
Bio-SNG is produced by gasification of cellulosic materials (e.g. forestry residues, energy crops), whereas "biogas" is produced by a biological process - anaerobic digestion of organic materials (e.g. manure, organic waste).
Bio-SNG is typically produced via an initial gasification step followed by gas conditioning, SNG synthesis and gas upgrading. Bio-SNG can be used in a similar way to biomethane (biogas) generated via anaerobic digestion. Syngas may also be converted into liquid advanced biofuels. Syngas may be converted to diesel, ethanol (e.g. Fulcrum Bioenergy) or other fuel molecules (e.g. via Methanol To Gasoline technology).
Biomass Gasification Technology Assessment (US 2012)
In November 2012 an extensive Biomass Gasification Technology Assessment was produced by M. Worley and J. Yale, Harris Group Inc. on behalf of NREL. The goal was to solicit and review the technical and performance data of gasifier systems and develop preliminary capital cost estimates for the core equipment. Specifically, the assessments focused on gasification and tar reforming technologies that are capable of producing a syngas suitable for further treatment and conversion to liquid fuels.
Bio-SNG Projects in Europe
SNG Demonstration in Güssing
The Biomass CHP Plant Güssing, which started operation in 2002, has a fuel capacity of 8 MW and an electrical output of about 2 MWel with an electrical efficiency of about 25 %. Wood chips with a water content of 20 – 30 % are used as fuel. The plant consists of a dual fluidized bed steam gasifier, a two-stage gas cleaning system, a gas engine with an electricity generator, and a heat utilization system, offering a complete value chain demonstration from woody biomass to SNG.
Commercial bio-sng plants are expected to be in the scale of 20 to 200 MW. In the initial conversion step i.e. in the biomass gasification process wood chips are converted into a syngas or more general into a product gas. The FICFB gasification process has operated in Güssing since 2002 for a combined heat and power (CHP) plant and in this time has been in operations for many 10000s of hours. The product gas is delivered at ambient pressure, has a high content of CH4, higher hydrocarbons and tars. This product gas is suitable for SNG production.
The final conversion step consists of three individual steps, i.e. gas conditioning, SNG synthesis and gas upgrading. R&D work over the first 8 years at Güssing focused on gas conditioning and SNG synthesis. The pilot scale showed that fluidized bed SNG synthesis is possible. The whole process chain reaches high conversion efficiencies and has the potential for lower investment and lower operation costs than conventional SNG synthesis technology.
On 18 December 2012 it was announced that GoBiGas Phase 2, Sweden, has been selected to receive counterpart funding of €58.8m under the first call for proposals of the NER300 funding programme for innovative low-carbon technologies. The Project will demonstrate the large-scale conversion of low-quality wood into high quality synthetic natural gas (SNG) by indirect gasification at atmospheric pressure, gas cleaning, methane production (via nickel catalyst), pressurization and injecting the product into the regional gas network. The Project will make use of forestry feedstock, which consists of pulpwood and forest residues harvested from the surrounding areas of Gothenburg, the Lake Vänern and Baltic region. The volume of ~0.5 Mt/year of wet biomass will be used in the Project, which has an installed capacity of ~100 MWth to produce 800 GWh/year of gas (SNG).
Background to the GoBiGas project
The purpose of the GoBiGas project led by Göteborg Energie A/B is to build a large scale plant that converts low quality cellulosic materials to biofuel with a conversion rate of more than 60%. The plant will be built as a co-generation plant where most of the losses in the process are recovered, pushing the overall efficiency to around 90%. The initial plant has a capacity of 20 MW biomethane production, which is enough to supply some 15 000 passenger cars with biofuel. In a second phase, to be completed by 2015, the plant will be expanded to 100 MW capacity. The plant will have with a continuous operation of 8000 hours per year.
Biomethane is the 2nd generation biofuel that allows for the highest conversion factors in gasification processes, because it’s the simplest hydrocarbon that exists. It also allows for very efficient transportation through the natural gas grid, because biomethane and natural gas is the same chemical substance, but with different origins. This is already being practiced in Sweden and other Member States.
The project will result in substantial reductions in CO2 emissions, not only because of the small amounts of fossil fuels used in the WTW chain,resulting in CO2 savings of at least 85% for every unit of fossil fuel displaced, but most importantly it will provide very high CO2 savings per unit of land used for fuel production. Apart from the difference of yield in the different processes, the use of the waste heat in GoBiGas is an important element in the CO2 balance.
Gaya Demonstration Project
The Gaya Demonstration project, supported by the EC, aims to demonstrate a commercial pathway for gasification and methanation of residues (e.g. wood, straw) to produce synthetic biomethane at the industrial scale.
Cortus WoodRoll® Technology Sweden
Cortus has built an integrated production flow plant where the drying, pyrolysis and gasification of different biofuels is run at the scale of 500 kW. In February 2012, it was announced that the plant had succeeded to produce synthesis gas from biomass without traces of hydrocarbons. This 'breakthrough' facilitates the use of the synthesis gas for more cost-effective fuel production.
Following the success of these trials, the aim is to construct a ten times larger demonstration plant in Köping. The plant is constructed in cooperation with Torkapparater AB, Concordance AB, AGA Gas AB, ÅF and Sandvik Heating Technology, among others. Funding comes from the Swedish Energy Agency, Triple Steelix, Movexum and Cortus.
Bio-SNG Demonstration of the Production and Utilization of Synthetic Natural Gas (SNG) from Solid Biofuels (Bio-SNG) (TREN/05/FP6EN/S07.56632/019895)
The objective of the "Bio-SNG"-project is to demonstrate SNG (Synthetic Natural Gas) production from solid biofuels and to integrate this Bio-SNG into the existing energy infrastructure (i.e. fuel station for vehicles, natural gas grid). To meet the specifications required for the gas-utilisation in vehicles or the gas-feeding into an existing natural gas grid the produced SNG will be upgraded. Cars will be operated with this upgraded renewable gaseous fuel to demonstrate the powerful application within the transportation sector.
This overall system of SNG production and use options will be assessed comprehensively according to technical, economical and environemtnal aspects, as well as possible contributions within the European energy system. Thereby effects of the commercial implementation of SNG into the energy system will be examined and can be compared with other options to produce transportation fuel from biomass. Also the possibility of heat and power production from solid biofuels will be considered within this overall assessment e.g. by taking into consideration economic advantages beyond the pure fuel production for transport issues.
E.ON Bio2G Project
The E.ON Bio2G project in Sweden involves the design, erection and commissioning of a gasification plant with 200MW output, with construction planned to start in 2013.
Concord Blue / Blue Tower Gasification Technology
In Germany, Blue Tower (Concord Blue) is developing gasification technology to convert a wide range of wastes to energy via gasification system with up to 80% efficiency.
The ECN/HVC Project for BioSNG
ECN ECN has been developing a system for the conversion of dry lignocellulosic biomass into natural gas quality gas: BioSNG or Substitute Natural Gas from biomass. Technology choices have been based on the desire to have large-scale BioSNG plants with high overall efficiency. The ECN concept is based on so-called MILENA indirect gasification and OLGA tar removal.
The ECN concept offers 70% efficiency from biomass to BioSNG. A lab-scale system is available at ECN. A 1 MW pilot system at ECN is under commissioning for the two main parts of the system: the MILENA gasifier and the OLGA tar removal. HVC is a waste company, which is expanding its activities towards renewable energy. Joining the development of the BioSNG-concept perfectly fits in with HVC’s ambitions in the medium and long term. HVC intends to realize two demonstration plants to demonstrate the ECN-concept.
The first demo plant will be a ~10 MW CHP plant to demonstrate the combination of the MILENA and OLGA-processes. This will be operated from 2012. The second demo plant will be a ~50 MW SNG plant in which the MILENA and OLGA are up-scaled and further gas cleaning and methanation will be added. These additional units will be supplied by a large EPC, which will soon be involved in the development.
View Poster on ECN/HVC project ( 1.2 Mb PDF) presented at SPM2.
Biomethane (Biogas and Bio-SNG) for transport presentation
A global overview of Biomethane for Transport (covering BioGas and Bio-SNG) was presented by Deutsches Biomasse Forschungs Zentrum gemeinnützige GmbH at the "From today’s to tomorrow’s biofuels – From the Biofuels Directive to bio based transport systems in 2020; IEA Bioenergy Task 39 Subtask Policy and Implementation Workshop" on June 3-5, 2009, Dresden, Germany
SNG and Gasification Developments in the US
Sundrop Fuels has announced a partnership with ThyssenKrupp Uhde (Germany) to produce 50mgy of drop in biofuels (renewable gasoline) at a plant near Alexandria, Louisiana, with construction due to start later in 2012. The plant will combine natural gas and biomass (forest residues) using a commercial XTL process that integrates ThyssenKrupp Uhde’s High Temperature Winkler gasification process and gas cleaning, followed by methanol synthesis and methanol-to-gasoline (MTG) technology (licensed from Exonn Mobil).
The Rentech Inc. Port St. Joe Renewable Energy Project (Port St. Joe Project), in Florida, is an advanced-stage renewable power project that would employ a Rentech-SilvaGas biomass gasifier to provide synthesis gas to a combined–cycle power plant. The project is designed to produce approximately 55 megawatts net of renewable low-carbon base load electric power (RenPower™) from approximately 930 dry tons per day of woody biomass.