GASIFICATION OF WASTE WITH ENERGY RECOVERY

Planet Advantage Ltd: The BCB Project

Technology Type: Thermal Treatment

Project Description

The aim of this project is to process BCB’s hazardous and non-hazardous industrial and commercial waste with a mixture (up to 1:1) with municipal solid waste (MSW), utilising these wastes as a fuel for Planet’s gasification process. Initially, 40,000 tonnes p.a. will be processed with a planned future increase to 60,000 tonnes.

In the initial phase, up to 6 MWe will be generated for export to the grid along with 6 MWt (as hot water) which is available for local or domestic use.

The plant will be owned and operated by BCB Environmental Management

Technology Background

The technology utilises a number of Primary Gasification Chambers (PGC’s) into which the waste is loaded, without any requirement for shredding or pre-processing. Each of these PGC’s holds approximately 16 tonnes of waste and these individual batches are operated sequentially, providing an even and efficient release of rich producer gases (Syngas) – mainly hydrogen, methane and carbon monoxide. The Syngas is mixed with oxygen and oxidized in the Secondary Combustion Chamber (SCC).

Within the low temperature, non-turbulent environment the slow – quiet – gasification process produces only tiny amounts of particulates and the steady temperature state reduces the likelihood of nitrous oxide (NOx) forming. The high temperature burnout of the gases in the secondary chamber prevents dioxin formation. Long exposure to temperature in the PGC reduces the ash to an absolute minimum and the carbon residue in the ash is measured at less than 0.5% w/w, with no slagging and subsequent easy mechanical recovery of ferrous and non ferrous metals.

The hot exhaust gases from the SCC are cooled in a water tube boiler equipped with a superheater for steam production and an economiser to gain maximum efficiency from the energy in the Syngas. The high pressure steam is then passed to a multi-stage turbine/generator set for electricity production. The cooled exhaust gases are cleaned and polished in the dry flue gas treatment system prior to being exhausted through the main stack.

The dry flue gas treatment system uses sodium bicarbonate for acid gas neutralisation, activated carbon to remove traces of heavy metals, dioxins and furans, and a filter bag house to collect the spent scrubber consumables and any residual fly-ash.

Location

The primary and secondary chambers will be housed inside Unit 86 – which is another former aircraft hangar adjacent to the company’s existing facility – with the flue gas treatment system and turbine sited externally.

Inputs / Outputs

The plant will be capable of processing 120 tonnes per day, resulting in the following estimated outputs:-

• 6 MWe exported to the grid
• 6 MWt available for industrial/commercial/domestic use
• 9 tonnes per day of bottom ash
• 5 tonnes per day of spent scrubber consumables and fly-ash

Scale / Costs

The capital costs for the 40,000 tonne Phase 1 are:

• £14.5m process plant
• £2.5m building and civil works
• £1m grid connection

Operating costs (before depreciation and interest):

• Approximately £35 - £40 per tonne

Emissions

The gasification process out-performs traditional incineration technology to produce emissions well within the Waste Incineration Directive (WID) limits. The rural location of this particular facility is expected to dictate a standard that achieves in the region of 20% of the WID standard.

Other Planet Developments

In May 2006, Planet’s technology partners commissioned a new plant in Husavik, Iceland. The plant has been built and operated to EU standards - in particular WID. It deals with 8,000 tpa of mixed waste including:-

• Untreated MSW
• Industrial / commercial
• Construction / demolition
• Tyres
• Meat and fish processing
• Agricultural plastic film

The plant produces steam which is sold to the local energy company approximately 300 metres from the Husavik facility. Plans are already in place to double the size of this facility to cope with an enlarged geographical area.

In the UK, a number of other clients have agreed terms in principle and are proceeding with the planning process in readiness for developing similar facilties in the 10 – 60,000 tpa range

Contact Details
Planet Advantage Ltd
Ascot House
51 Water Street
Radcliffe
Manchester
M26 3DE
Tel: 0161 724 2222
Fax: 0161 724 2229
email : info@planetgroup.co.uk
web: www.planetgroup.co.uk