Gasifiers current developments

Two major types of gasifiers currently in development are direct-fired gasifiers, using air, and the indirect-fired method, where heated sand surrounds biomass and gasifies it. These design schemes are described in Chapter 3. 

Current Status The U.S. Department of Energy (DOE) and its private-sector collaborators have substantially advanced the development of gasification-based power systems during the last decade. This section describes the current status for the various types of gasifiers used. 

The company Noell in Germany, currently owned by Future Energy GmbH, has developed a down-fired entrained flow reactor (EFR). Instead of burners at the side of the reactor, this gasifier only consists of a single burner in the top part, which results in a simpler and lower cost reactor. Also, the control of this single burner is easier than the former types mentioned with a resulting lower capital and operational cost related. 

To adapt for wood an advanced lignite gasifier that operates co-current at 10 atm in a fluidized bed. This system has many advantages, produces a very clean gas, but is now in a very preliminary development stage. 

Although the data obtained in these studies have been valuable in interpreting the slagging phenomena observed in gasifier tests, a more fundamental objective of the current work is to develop correlations that can be used to predict a priori the viscosity behavior of low-rank-coal slags from a knowledge of the ash or slag composition. 

The comparison mentioned under 2. will result in knowledge on which method can reliably be used under which conditions. As other methods might be simpler (in terms of man-hours and equipment needed to perform the measurement) compared to the Guideline or produce online results on-site, we have named them shortcut methods . Examples of these methods are a) the solid phase adsorption (SPA) method developed by KTH (7], b) a number of solvent-free tar collection systems used by BTG, BEF, IGT [8-10] and c) the FID online tar analysing method under development at the University of Stuttgart (11,12]. Currently it is unknown under which conditions these methods give reliable results, for example it is unknown whether the SPA method can be used for updraft gasifier tars and at which conditions the solvent-free methods fail to collect ail tars, for instance as a result of aerosol formation. 

Although much enthusiasm currently exists for producing ethanol fuels from local sugar crops in developing nations, the results of this very cursory analysis indicate to us that at least one other option could supplement petroleum fuels used in transportation with biomass fuels at comparable or lower capital investments. This option is the use of vehicle-mounted gasifiers. 

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