Research projects

Research in waste to energy (WTE) plants to improve the electrical efficiency is a very important area in order to gain increased sustainable renewable energy as electricity. Waste incineration plants have less electrical efficiency compared to other combustion-based plants due to the high temperature corrosion effects taking place in waste incineration plants.

Experiments, August 2005

Waste burning at port 1 In the summer of 2005, we performed gas extraction experiments through some port holes above a full-scale grate-fired plant at Vestforbrænding line 5. It can become quite hot (1400 degrees celsius) in the flames when the waste is being incinerated.

Cooled probe at port 5 with sulphur The probes were inserted at 6 holes above and along the grate. This probe is from port 5, where no more combustion is taking place. The yellow on the probe is sulphur.

The gas is let through some filters and some washbottles containing a mixture of ultra pure water and ammonia (basic) or HNO3/H2O2 (acid, oxidizing). Wash bottles The ammonia solution is for high soluble chlorine which is present as HCl(g). It also catches salts of Sodium (Na) and Potassiums (K). The acidic solution oxidizes metals such as lead (Pb), Zinc (Zn), Copper (Cu), and sulphur present as SO2. After sampling the gas, the aqueous samples be analysed using ICP-OES (Inductively Coupled Plasma - Optical Emission Spectroscopy) with a specially filter for measuring chlorine (Cl). The chlorine can also be measured by using IC (Ion chromatography).

Very hot probe The probes are made of sintered aluminimium oxide (Al2O3) also called alumina. The probes are protected by a steel casing as the alumina probes are very fragile and somewhat expensive (about 2000 danish kroner, approx. 350 USD). The probes were 250 cm.

Very hot probe, closeup Notice how the deposit on the probe is evaporating. It gave these cracking sounds during cooling and when the deposits were falling off.

New experiments are planned in the summer of 2006 where the sampling will take place with a larger sampling train of serial coupled wash bottles. Also the new experiments aim to reduce the amount of tar, that condensed in the tubes and other places in the sampling system. The condensed tar gave rise to a series of troublesome investigations on how to extract from the tubes. Normally this would have been done using the aqueous wash bottle liquid, but this would not dissolve the tar. A mixture of toluene and methanol (90/10) were used to extract from the tubes.

Experiments 2006

Still in the planning and designing phase of the new probes with additional air intake to completely combust the gas before sampling.

Links

CHEC Research Centre
Department of Chemical Engineering
Technical University of Denmark
Babcock & Wilcox Vølund ApS
Vestforbrænding

Writing scientific articles

SI units and uncertainty page on NIST homepage: http://physics.nist.gov/Pubs/pdf.html.

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