Siemens gasification technology was originally developed by Deutsches Brennstoffinstitut (DBI) in Freiberg, Germany for the gasification of pulverized local brown coal and other solid feedstocks in 1975. The Noell group acquired the technology in 1991 and developed it further to handle liquid residues and wastes. The gasifier also operated under the name of Babcock Borsig and Future Energy before being acquired by Siemens in 2006.
The Siemens gasifier is a dry-feed, pressurized, entrained-flow reactor, which can be supplied with either a refractory lining for low ash feedstocks or with a cooling screen in the gasification section of the gasifier. The cooling screen consists of a gas-tight membrane wall structure that is studded and refractory-lined with a thin layer of silicon carbide for protection. The molten slag formed in the gasifier chamber cools and solidifies as it contacts the cooling screen, forming a compact slag layer, protecting it from further damage by the flowing slag. Once a slag layer is formed over the cooling screen, subsequent hot slag flows down the reactor chamber into the quench section of the gasifier where it solidifies upon contact with water from a ring of quench nozzles and is removed through a lock hopper.
Feedstocks with an ash content of greater than two percent by weight are preferred when using the cooling screen design; in this scenario the gasifier can achieve carbon conversion rates higher than 99%. Siemens gasification technology is well suited for coals from anthracite to lignite, as well as biomass, petcoke, and residual oil.
Demonstration and Early Commercialization
In addition to its 23 year of operating experience at the SVZ Schwarze Pumpe Gasification Complex in Saxony, Germany, Siemens gasifiers have been selected for use in a number of gasification projects in around the world. A Siemens SFG-200 gasifier has been operating since 2008 in the Czech Republic on liquid tars and oils. The first five Siemens SFG-500 gasifiers entered commercial operation in 2011 in the Shenhua Ningxia Coal Industry, NCPP I coal to polypropylene project in China. Eight SFG-500 gasifiers are being manufactured for a coal to SNG project in western China and the Texas Clean Energy Project to be located in Odessa, TX will use 2 Siemens SFG-500 gasifiers.