SYNTHETIC NATURAL GAS (SNG) - STATE-OF-THE-ART TECHNOLOGY AND APPLICATION REVIEW

Synthetic natural gas (SNG) can be produced by thermochemical or hydrothermal conversion of carbon containing fuels like biomass or coal with subsequent cleaning, methanation and upgrading. In contrast to fossil natural gas, the biomass-derived SNG (Bio-SNG) has a neutral or even negative CO2 balance due to CO2 capture and storage.Although the SNG production process is not a ?new? technology, there is still no commercial break-through of the technology for biomass. So far concepts for SNG plants range from small applications around few MWth (> 1MWth) up to several 100 MWth. Whereas small size has the advantages of easy, local supply of biomass and local heat sinks, big industrial scale plants have the inherent higher efficiency due to scale up effects. Furthermore, various biomass gasification technologies are available but not all of them are suitable for a subsequent SNG production. The allothermal gasification has some advantages regarding the gas composition (low N2 content in the product gas).In general, all SNG processes from synthesis gas contain a gas cleaning, a methanation and a subsequent upgrading/conditioning of the raw SNG. However, in detail, there are some different concepts for the conversion and lots of elaborate challenges to solve, for example the tar problematic. One critical point is the methanation, which may be conducted in a fluidized or a fixed bed catalytic reactor with intermediate cooling or recirculation of product gas but as well can be done in liquid phase (slurry reactor). The critical parameter is the removal of reaction heat and so far no final design is established.In Europe there are some prominent SNG example facilities mainly in the pilot plant stage. An overview of SNG projects and operating plants and their technical specifications are shown. Today the most prominent Bio-SNG plants are located in Austria (Güssing), the Netherlands and Sweden.For the final grid injection SNG has to fulfill the respective legal conditions, as for example in Germany specified in the G260 worksheet. Economic considerations as well as legal boundary conditions are outlined.     «

Synthetic natural gas (SNG) can be produced by thermochemical or hydrothermal conversion of carbon containing fuels like biomass or coal with subsequent cleaning, methanation and upgrading. In contrast to fossil natural gas, the biomass-derived SNG (Bio-SNG) has a neutral or even negative CO2 balance due to CO2 capture and storage.Although the SNG production process is not a ?new? technology, there is still no commercial break-through of the technology for biomass. So far concepts for SNG plants...     »