Waste processing at the Energos energy recovery plant on the Isle of Wight, have temporarily suspended their gasification process because of “abnormal” emissions of dioxins.
Energos background from Island Pulse News: For the first time in the UK and after a four month delay on the noted opening, the Energos gasification plant on the Isle of Wight, began processing waste in May 2008.
Simon Bacon Spokesperson for S.S.A.I.N provided the heads up on this news:
The Waste Gas Technology waste plant on the IOW broke the legal emission limit for highly toxic Dioxins and Furans when tested in March. The limit if 0.1 nanograms per cubic metre however the plant emited 0.8616 nanograms per cubic metre which was clearly well over the limit. It also has major down times which raise a number of questions.
Tony Grimshaw, Technical Director for Energos:
“Waste Gas Technology has halted operations while Energos engineers deal with this unprecedented problem.”
A media release from the company states:
Waste Gas Technology (WGT) has temporarily suspended waste processing operations at its hybrid Energos energy recovery plant on the Isle of Wight to investigate abnormal dioxin emission test results and take action to restore previous low levels.
Routine independent emissions tests, undertaken as part of the environmental permit at the plant, reported a level of 0.86 ng/m3, which exceeded the company’s own established low standard and the permitted level. All other emissions tested were well within the EU limits.
The hybrid Energos Isle of Wight facility, owned and operated by Waste Gas Technology Limited, is totally different from any other previous or planned Energos projects because it involved the retrofit of an Energos gasifier to the front end of a former energy recovery plant. Much existing infrastructure and equipment was re-used, including the flue gas cleaning equipment where the current problem has arisen.
Tony Grimshaw, Technical Director for Energos:
In 13 years and 400,000 plus hours of safe operation on eight sites that utilise the Energos gasification technology the company has maintained exceptionally low dioxin emission levels. These are typically less than 5% of the stringent EU limit. In fact, independent emissions results from our newest plant in Norway show that dioxin emissions are below the limit of detection.
“The previous independent dioxin test completed on the Isle of Wight in 2009 was just 3.4% of the accepted EU safe level and typical of excellent environmental performance at all of our plants. Since then, continuous monitoring of combustion performance indicates that these low levels of dioxin emissions have been maintained until the recent problem.
Following an initial investigation, plans were made together with the Environment Agency to re-start the plant and to repeat the test. The results of these initial tests showed that while the dioxin emission levels had been greatly reduced, they were still above the limit value (0.138 and 0.148 over two consecutive days). Further action is being taken to correct a problem with the carbon injection system and WGT is confident that planned tests, to be carried out with the agreement of the Environment Agency in approximately two-weeks time, will demonstrate that low emission levels have been restored.
Added Tony Grimshaw:
“Our engineers believe they have found a lasting solution to this problem, but operations will not re-start until the matter is fully resolved and rigorous independent testing proves, without doubt, that emissions are restored to previous low levels. We would like to reassure residents living near proposed Energos sites that this is an isolated result from a very different type of hybrid plant. We would ask them to consider our, otherwise, unblemished environmental record with independently measured low emission data spanning more than a decade. The fact remains that the Energos gasification system is an extremely good process, with an excellent track record and this isolated incident at a non-standard plant does not change that.”
The Energos technology offers a clean energy recovery from waste solution that provides a best practice alternative to mass-burn incineration and a proven alternative to landfill. Its new generation gasification technology uses an advanced two-stage thermal treatment process that converts non-recyclable waste into a gas by using the heat of partial combustion to liberate the hydrogen and carbon within the waste.
Leftover waste that can’t be recycled and would otherwise be sent to landfill is fed into the gasification chamber, where it is manufactured into a syngas. This syngas is then transferred to a secondary oxidation chamber where it is fully combusted in a controlled environment that enables much tighter control than can be achieved in conventional energy from waste plants – resulting in extremely low emissions. The resulting heat energy is used to produce steam, which can be used to supply renewable heat and/or electricity.
Energos prides itself on achieving exceptionally low emissions, particularly dioxin, which is achieved by the extremely effective control of the combustion of the syngas in the second stage combined with the unique design of the boiler system that cools the gas down rapidly to reduce the reformation of dioxins. Finally, any residual dioxins are removed using carbon and a filter to remove dust particles.
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