Is Pyrolysis Incineration?

Question: Is WP2's Pyrolysis Facility an Incinerator?

One of the contentious issues surrounding WP2’s proposed facility at The Old Railway Yard, Haybridge, is the exact nature of the technology that they will be using. WP2 claims that their pyrolysis facility is not an incinerator. WEPG have sourced the documents that give us an insight into answering this question. These are presented below, along with the original source location so that individuals who wish to follow this point up may do so.

WP2 categorically claim that it is not an incinerator or incineration in any form. However, in our opinion this is merely a question of semantics at best, or a deliberate attempt by WP2 to mislead the public at worst. As the following sources clearly demonstrate, the process proposed by WP2 is a form of incineration and is regulated as such by the Environment Agency (EA) through the Waste Incineration Directive (WID) and Integrated Pollution Prevention Control (IPPC) licensing.

1. EU Definition 2000/76/EC, Article 3(4) (which can be downloaded here) should leave us is no doubt that taking the facility as a whole, an incinerator is exactly what WP2 are proposing here: ‘incineration plant’ means any stationary or mobile technical unit and equipment dedicated to the thermal treatment of wastes with or without recovery of the combustion heat generated. This includes the incineration by oxidation of waste as well as other thermal treatment processes such as pyrolysis, gasification or plasma processes in so far as the substances resulting from the treatment are subsequently incinerated. This definition covers the site and the entire incineration plant including all incineration lines, waste reception, storage, on site pretreatment facilities, waste-fuel and air-supply systems, boiler, facilities for the treatment of exhaust gases, on-site facilities for treatment or storage of residues and waste water, stack, devices and systems for controlling incineration operations, recording and monitoring incineration conditions;

2. The Wells Journal (May 5, 2005) in an article titled ‘Chemical Engineer David Green Responds to Questions on WP2’s Proposal’. posed the question, ‘Is it incineration?’, regarding the facility proposed by WP2 to chemical engineer David Green (of NGreen Environmental Consultants Ltd). He is a committee member of the Environmental Protection Subject Group for the Institute of Chemical Engineers (ICE). His response was: ‘Pyrolysis itself is not incineration because there is no direct combustion. However, if the gas produced from the process is subsequently burned, the overall process is classified as incineration according to European and UK legislation. [This is the legislation quoted in (a) above]. One potential advantage over direct incineration is that the gases can be cleaned before combustion, which is a more efficient method’.

The potential advantage mentioned in the last sentence remains ‘potential’, as to date, no such pre-combustion cleaning has been undertaken in a Graveson Energy Management (GEM, proposed supplier of WP2's 'pyrolysis' technology) facility of this nature. Hence, uncertainty remains over the effectiveness of the cleaning process, and disposal of the toxic products from this process, as well as the ‘advantage’ that this will make to the emissions profile from the process. The EA reviewed these ‘advantages’ in a technical report, which is described in (d) below, and found them to be ‘unsubstantiated’

3. Juniper Consultancy Services Ltd are providers of a *global directory of pyrolysis and gasification processes, wherein they also list an entry for GEM. In conclusion to their discussion as to whether the processes of pyrolysis and gasification should be considered as incineration, they offer (pp. E:242): ‘The final arbiter as to whether gasification and pyrolysis will be considered as surrogate processes of incineration, in relation to waste treatment applications, will be the regulators’ - the EU and UK legislation as listed in heading 1 above makes it categorically clear that these processes are merely incineration by another name. In their subsequent discussion of regulation (pp. E:253) though, the same authors defend their notion of gasification processes producing syngas that can be cleaned prior to combustion as falling outside the WID regulations, promoting it as technology of simple ‘gas utilisation’. However, with particular reference to the GEM process emissions (pp. E:382-387), they note: ‘There may be an issue in the context of minimum residence times imposed in Europe under the Waste Incineration Directive (WID), under which (in our view) this process would be regulated’. Further to this, WP2 will have to submit an application to the EA for an Integrated Pollution Prevention Control (IPPC) permit for their proposed pyrolysis facility at the Haybridge site, in line with its necessary regulation as an incinerator under the WID.

*Heermann, C., Schwager, F. J. & Whiting, K. J. (2001), ‘Pyrolysis & Gasification of Waste: A Worldwide Technology & Business Review’, 2^nd Edition, Juniper Consultancy Services Ltd.

4. R&D Technical Report on Pyrolysis & Gasification Activities P4-100TR In this technical report of ‘waste pyrolysis and gasification activities’ published by the *EA, the authors note (pp. 58): ‘A key conclusion from this work is that, based on current evidence, waste pyrolysis and gasification plants will have similar pollution potential to waste combustion plants. The techniques for controlling pollution levels are broadly the same as those applicable to waste combustion and the achievable release levels should broadly be the same. Claims that pyrolysis and gasification processes are inherently less polluting than conventional waste combustion processes have not yet been substantiated’. As would be anticipated from this conclusion, pyrolysis and gasification systems will be regulated just as incinerators, under WID.

*Higham, I, Palacios, I & Barker, N. (2001). Review of BAT for New Waste Incineration Issues, R&D Technical Report on Pyrolysis & Gasification Activities P4-100TR. Produced by AEA Technology Environment (R&D Project P4-100) and published by the Environment Agency, Bristol. ISBN: 1 58705 717 1.

5. WP2's Website It is probably pertinent now to examine the line that WP2 have adopted over the question of whether their proposed process is incineration. Not surprisingly, they claim that it is not! A download from their website, ‘Frequently Asked Questions’, deserves re-evaluation:

Q. If it is not incineration, how does it differ?

A. In an incinerator gases are driven out of the feedstock by the high temperature of the ‘furnace’, however they are then immediately combusted within the furnace with oxygen and the carbon residues creating carbon dioxide and steam amongst other ‘flue’ gases. Heat is recovered from the hot ‘flue’ gases before they are scrubbed to remove unacceptable chlorides and oxides of sulphur and nitrogen. The recovered heat is used to produce steam which is used either as a source of industrial heat or to drive steam turbines. The other by-product of incineration is ash.

In pyrolysis the hot gases driven out of the feedstock are not combusted. They are cooled, scrubbed and then used directly as a source of industrial heat or to fire lean burn reciprocating engines that drive generators [i.e. to release the ‘heat’ the gases must be incinerated]. Although it has a calorific value, the residual carbon is not combusted with oxygen, thus reducing the level of carbon dioxide pumped direct into the atmosphere.

We have added our own interpretations to the last paragraph in square brackets – in our opinion, it seems they couldn’t bring themselves to say the obvious!

Answer: YES. It is incineration by another name, presumably to soften public perception.

Quote To Note

In a House of Lords enquiry on 14th April 1999, Environment Minister Michael Meacher said, "Incinerator plants are the source of serious toxic pollutants: dioxins; furans; acid gases; particulates; heavy metals; and they all need to be treated very seriously. There must be absolute prioritisation given to human health requirements and protection of the environment. I repeat the emissions from incinerator processes are extremely toxic. Some of the emissions are carcinogenic. We must use every reasonable instrument to eliminate them altogether."