to read the full report - Ecolateral by Peter Jones
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Evaluation of Opportunities for Converting Indigenous UK Wastes <strong>to</strong> Wastes and Energy<br />
AEA/ED45551/Issue 1<br />
Table 77 Gasifier feeds<strong>to</strong>ck requirements<br />
Gasifier<br />
Type<br />
Fixed bed<br />
downdraft<br />
Typical<br />
Size MW<br />
fuel<br />
1 MW<br />
modules<br />
Fixed bed 10 MW<br />
updraft modules<br />
Fluidised 25MW<br />
bed direct or upwards<br />
indirect<br />
Heated kilns 20MW<br />
modules<br />
Small<br />
heated<br />
tubes<br />
Large<br />
heated<br />
tubes<br />
Large<br />
entrained<br />
flow<br />
10 MW<br />
modules<br />
Fuel Quality<br />
Regularly<br />
sized, dry and<br />
clean wood<br />
chips with low<br />
ash. Possibly<br />
pellets<br />
Wood chip<br />
SRF<br />
Waste Wood<br />
Clean Wood<br />
<br />
most qualities <br />
Most dry<br />
shredded<br />
materials<br />
Most shredded<br />
materials not<br />
necessarily dry<br />
Most dry<br />
shredded<br />
materials not<br />
necessarily dry<br />
50MW Minimally<br />
sorted or<br />
prepared<br />
100 MW<br />
upwards<br />
Plasma 2MW<br />
upwards<br />
T C Fuels – Thermochemical Fuels<br />
materials<br />
Capable of<br />
high pressure<br />
pneumatic<br />
transport or<br />
slurry<br />
component<br />
Most shredded<br />
materials not<br />
necessarily dry<br />
Domestic Pellet<br />
Industrial Pellet<br />
Unsorted Waste<br />
Wet Wastes<br />
Agricultural<br />
Residues<br />
T C Fuels<br />
<br />
<br />
<br />
<br />
<br />
<br />
With <strong>the</strong> exception of <strong>the</strong> direct fluidised beds none of <strong>the</strong> gasification processes above can be<br />
considered <strong>to</strong> be widely available commercially. The allocation of feeds<strong>to</strong>ck is <strong>the</strong>refore an estimate<br />
based on AEA knowledge.<br />
Primary Gas Cleaning<br />
The gas from <strong>the</strong> gasifier contains a range of contaminants. The most important are dust and residual<br />
organic compounds or tars that can cause difficulties for <strong>the</strong> following conversion process. The extent of<br />
cleaning necessary varies with <strong>the</strong> end use of <strong>the</strong> gas, so a fluidised bed gasifier supplying hot gas <strong>to</strong> a<br />
coal fired utility boiler will have minimal dust removal whereas a unit supplying gas <strong>to</strong> a reciprocating<br />
engine will need reliable dust, tar and acid gas removal. Syn<strong>the</strong>sis processes require a very high level of<br />
purity <strong>to</strong> avoid poisoning of <strong>the</strong> catalysts used in <strong>the</strong> reactions - <strong>the</strong>se are more properly regarded as part<br />
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