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 />
wastes. The company has plans <strong>to</strong> complete <strong>the</strong> installation of a larger fixed bed British Gas/Lurgi<br />
slagging gasifier.<br />
The medium CV product gas is cleaned and used <strong>to</strong> generate electricity, through a combined cycle using<br />
a 44 MWe Als<strong>to</strong>m Turbine and a 30 MWe steam turbine. There are plans <strong>to</strong> syn<strong>the</strong>sise methanol <strong>to</strong><br />
enhance <strong>the</strong> degree of recycling that can be achieved in <strong>the</strong> installation.<br />
Current capacities are<br />
• Plastics 5 <strong>to</strong>nnes/hr<br />
• Wood 6 <strong>to</strong>nnes/hr<br />
• Liquid waste 200 <strong>to</strong>nnes/day<br />
• Domestic waste 20 <strong>to</strong>nnes/ hr<br />
All residues leave <strong>the</strong> site as inert slag<br />
This project represents a technically viable waste disposal and energy complex on a very large scale. It<br />
is an engineering success that combines a high degree of material recovery with a high electrical<br />
efficiency. It did however make substantial use of <strong>the</strong> existing brown coal processing plant so replication<br />
may prove difficult.<br />
Choren, Freiberg, Germany<br />
CHOREN Gmbh have been developing a process <strong>to</strong> produce a renewable fuel compatible with <strong>the</strong> diesel<br />
fuel infrastructure that uses lignocellulose materials. The concept is <strong>to</strong> gasify biomass and use <strong>the</strong><br />
resultant gas as a feeds<strong>to</strong>ck <strong>to</strong> syn<strong>the</strong>sise alkanes using <strong>the</strong> Fischer Tropsch reaction.<br />
The process for <strong>the</strong> gasification of wood and similar materials is based on an entrained flow gasifier used<br />
for brown coal in <strong>the</strong> 1980’s in <strong>the</strong> former DDR. The gasification process comprises two steps, slow<br />
pyrolysis of chipped material followed <strong>by</strong> <strong>the</strong> oxygen gasification of <strong>the</strong> tar vapours and char produced.<br />
The oxygen gasifier is interesting in that it is arranged in two stages; <strong>the</strong> first gasifies <strong>the</strong> pyrolysis<br />
vapours in oxygen and <strong>the</strong> second gasifies <strong>the</strong> char <strong>by</strong> reaction with <strong>the</strong> product gases from <strong>the</strong> first<br />
stage, having first been finely ground. A consequence of <strong>the</strong> second reaction is that <strong>the</strong> gasses are<br />
cooled <strong>by</strong> <strong>the</strong> endo<strong>the</strong>rmic reaction of char with CO2.<br />
The syn<strong>the</strong>sis gas from <strong>the</strong> gasifier is essentially free from tar contamination and can be cleaned <strong>by</strong><br />
filtration before <strong>the</strong> CO/H2 ratio is adjusted using <strong>the</strong> CO shift reaction. CO2 is <strong>the</strong>n removed <strong>by</strong> scrubbing<br />
and <strong>the</strong> gas passed fur<strong>the</strong>r in<strong>to</strong> <strong>the</strong> Fischer Tropsch reac<strong>to</strong>r <strong>to</strong> form a product mixture of diesel oil and<br />
naphtha.<br />
The first installation was a pilot, or alpha, plant which operated from <strong>the</strong> mid 90’s <strong>to</strong> 2005 and had a fuel<br />
input of 1MW. The second, or beta, installation is a demonstration with a fuel input of 45MW and is just<br />
undergoing commissioning and testing near Freiberg in Saxony. The third installation, or sigma, is a <strong>full</strong><br />
scale commercial unit of 640 MW which is in <strong>the</strong> design phase and should enter service in 2015.<br />
The overall energy balance of <strong>the</strong> beta demonstration unit is predicted <strong>to</strong> convert 100% fuel energy value<br />
<strong>to</strong> 39% diesel, 13% naphtha, and 6% export electricity giving an overall efficiency of 58% fuel <strong>to</strong> energy<br />
product. This is expected <strong>to</strong> improve with scale up.<br />
The development of <strong>the</strong> process is being supported <strong>by</strong> a consortium of Daimler Chrysler, Shell,<br />
Volkswagen, and o<strong>the</strong>rs with assistance from local German authorities and <strong>the</strong> EU. 292<br />
292 Start-up of <strong>the</strong> first commercial BTL production facility. Lecture <strong>by</strong> Dr. Chris<strong>to</strong>ph Kiener, Project Development Manager at <strong>the</strong> 16th European<br />
Biomass Conference & Exhibition, 3. June 2008, Valencia. www.choren.com<br />
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