Page 23 - Impiantistica Italiana Maggio Giugno 2014

The project consisted of small-scale experiments,
process evaluations and design, construction and
operation of a 0.5 MW process demonstration unit
at VTT. The PDU (Process Demonstration Unit test
runs were started in 2006 and the frst part of the
development path was concluded in 2007.

2.3.2. The BtL demonstration plant
The second step in the development path was a
long term demonstration in a larger scale. Toge-
Fig. 3 - Lay out model of 150 and following that a demonstration programme ther with FW, Finnish joint venture NSE Biofuels
MWth CFB gasifer was launched, which was continued until June built a demonstration plant in Varkaus, Finland, to
2000. The accumulated operating experience demonstrate long term gas production and gas
amounts to about 8500 hours of gasifcation runs cleaning to meet the requirements of FT-synthesis.
and about 3600 hours of operation as a fully inte- Gas for the gas cleaning test plant was produced in
grated plant as per the end of 1999. The test runs an atmospheric oxygen-steam blown CFB gasifer,
were very successful and the plant was operated which also supplied, and still supplies today, gas
on different wood fuels as well as straw and RDF. for the lime kiln of the Stora Enso pulp and paper
One of the last tests included operation on 100% mill. Gas produced in the gasifer is referred to here
straw, which was accomplished without disturban- as “raw gas” to make a clear difference between
ces or problems. cleaned and reformed gas, which is referred to as
“product gas”.

Fig. 4 - Värnamo biomass
IGCC demonstration plant
(FWE scope) and key pro-
cess data
2.3. Foster Wheeler oxygen steam The gasifer is a 12 MW circulating fuidized bed
th
unit, which has been running since the end of
blown gasifcation and gas 2008. It started frst as an air-blown gasifer in order
to produce only raw gas for the lime kiln. In 2009
cleaning development the gasifer was operated for the frst time using
a mixture of oxygen and steam as the fuidizing
2.3.1. Finnish approach agent. Since then the gasifer was mainly operated
The development of the ultra clean gas technology in the oxygen-steam mode to produce high calori-
for the future applications was launched in 2004 in fc and low nitrogen content gas for the 5 MW gas
th
Finland as a publicly funded project with some in- cleaning demonstration plant. The whole process
dustrial partners. In this frst stage of development chain of the plant is shown in fgure 5.
work Foster Wheeler was one of the biggest indu- FW supplied the 12 MW CFB gasifer with au-
th
strial partners in a project which was coordinated xiliaries and some of the main equipment for the
by VTT (Technical Research Center of Finland). gas cleaning plant: gas coolers, hot gas flters, ash

Impiantistica Italiana - Maggio-Giugno 2014 19