Success histories of gasification development

 

In Finland, research and development activities gasification began in the 1970s. In the 1980s, the application of simple gasification air system first performed and main combined heat and power plant burning lime (lime kilns). Furthermore, in 1986 successfully built updraft gasification systems that produce heat 5 MWth. In almost the same time, gasification systems CFB (circulating fluidized bed) was also built with a power output of 15-35 MWth for the needs of pulp-paper industry (pulp). In the 1990s, IGCC (integrated gasification combined cycle) is also introduced, but because it needs huge resources into further development constraints [1]. Biomass gasification systems are generally only suitable for small and medium scale up to 10 MWe power.

Fig. Bioner Gasification in Finland [1].

With updraft system, biomass is inserted from the top of reactor. The presence of air and steam from below the reactor that moves up causing the biomass will have a series of processes. During the trip biomass from top to bottom reactor, biomass will experience drying, pyrolysis, gasification and combustion. Ash removed from the bottom of the reactors. Gas results updraft gasification process systems containing oil and tar in large numbers. The resulting gas temperature is low (80-300oC for biomass or 300-600oC for coal). Bottom ash (bottom ash) generally burn completely and leaves no burning charcoal in the amount that can be ignored. Dust generated is also relatively low because the gas velocity used was also low and is caused also by the "filtering effect" on the drying and pyrolysis [1].

Because the amount of tar produced quite a lot, then the gases from the gasification can not be directly inserted into the internal combustion engine (IC, internal combustion). Because the tar too, so that piping system needs to be cleaned once per 2-6 weeks depending on the type of fuel used.

In 1980, thermal power from the gasification Bionerr Finland is 1.5 MWth. The fuel used is wood chips, forest waste, peat, straw, pellets, coal and mix. With a moisture content of wood used by 41%, the gases released from the gasification process is 30% CO, 11% H2, 3% CH4, 7% CO2, and 49% N2 with 6.2 equivalents HHV MJ/m3n. Tar produced between 50-100 g/m3n. In 1986, the capacity of 8 units Bioneer Finland is 4-5 MWth.

Year 1999-2001 was developed type of updraft gasification combined with downdraft with a capacity of 500 kWth. As is known, type of downdraft gasification tar yield is lower than other types of updraft. This is because tar brought together the results of pyrolysis gas and then goes into the gasification and high temperature combustion. In the area of gasification and combustion of this, then tar will unravel. The result of the gases from this downdraft gasification system after filtered and cooled can be directly inserted into the internal combustion engine. However, on the commercialization tahun2 not yet done, because to ensure that low-tar required type of biomass with high quality.

The next development occurred in 1997's with still using the system downdraft and updraft gasification system. Two types of gas are separated and clean gases can be directly inserted into the internal combustion engine, while the gases are dirtier (with more tar) is used for the boiler. Planned capacity in 2001 is 2 MW (1.1 MWth and 450 Kwe). Gasification was built in Tervola, Finland.

Fig. Gasification Entimos Oy, in Tervola, Finland [1].

 

Fig. Sampe of gasification wood boilers

 

[1] ____, 2002, Review of Finnish Biomass Gasification Technologies, technical report, VTT, Finland.