• Kurkela, Esa
• Simell, Pekka
• Barbagli, Francesco
• Haavisto, Ilkka
• Ståhlberg, Pekka
• Berna, Gianni

Abstract

The project concerned three different approaches toachieve reliable operationin fixed-bed gasification ofavailable biomass residues. The first approach was basedon the pretreatment of fuels for use in standarddowndraft gasifiers. The second one was based on using acommercially available updraft fixed-bed gasifier forheating applications. The third was based on thedevelopmentg of a new type of gasifier that wereindependent of the natural descending fuel flow caused bygravity.The downdraft gasification tests were carried out inItaly in a gasifier-engine-generator facility with arange of Italian biofuels, the aim being to createcriteria for fuel selection, collect reliable performancedata with suitable fuels and to identify technicalpossibilities for broadening the feedstock basis by usingmixture fuels and additives. The test results andexperiences clearly demonstrated the limitations of thistype of commercial gasification technology.Operation experiences of commercial updraft gasifiersoperating in Finland and Sweden were collected andevaluated. These updraft gasifiers operate well with sodpeat and wood chips. However, these gasifiers cannotoperate reliably with low-bulk density fibours fuels likebark, sawdust and shavings.The third technical approach was realised by designing,constructing and testing a pilot plant of a new type ofgasifier, based on forced fuel flow and suitable forlow-bulk-density fibrous biomass fuels. The pilot plantwas connected to a secondary catalytic gas cleaningdevice, which made it possible to produce tar-free gassuitable for engine use. This new fixed-bed gasifiermakes it possble to utilise such biomass residues andenergy crops that cannot be used in the presentlyavailable fixed-bed gasifiers, like forest residue chips,sawdust and crushed bark. However, further work isrequired to demonstrate the whole gasifier, gas cleaningand engine concept and to define the lifetime andavailability of the catalytic gas cleaning system.

Topics

• density
• wood
• gasification