BASF Metal Recycling 

In February 2011 Lührfilter Ltd commissioned an emission abatement system for the collection of dust and fume arising from three incineration furnaces, for BASF Metals Recycling Ltd (formally Engelhard Sales Limited) at their works in Cinderford. The plant was installed to achieve tighter operating limits as part of their IPPC Operating Licence.

The plant was designed to provide flexibility in operation of the 3 incineration furnaces. The production pattern was such that all three furnaces could operate simultaneously or any one of the individual furnaces. The off gas temperature from the furnaces could be as high as 720ºC

The filtration system was configured with individual headers all in various grades of stainless steel up to the base of the quench tower and a common header from this point up to the inlet of the quench tower. 

As the oxygen content on emission warranties was critical all expansion joints and dampers were specifically designed to reduce the ingress of oxygenated dilution air. 

The process gases are cooled down by use of a Lührfilter Vertical quench tower to control the input temperature to the bag filter .The quench tower complete with its own dedicated pump station and weather proof housing was also installed as part of the package, this system cools the process gases by the use of atomised water (atomisation by compressed air), thus continually controlling the output temperature to 180°C

The filtration system and fan was sized to handle the maximum extraction from all three incineration furnaces, the filter has a compressed air On-line cleaning system type DF and utilises our KUVIII additive re-circulation system and incorporates the Lührfilter dry gas scrubbing reaction chamber and conditioner drum to reduce the acidic compounds. This involves the injection of two reagent powders into the process gas stream. A Lührfilter patented conditioner operates within the reaction chamber. The function of these two items is to provide full utilization of the reagent therefore increasing the efficiency of acidic adsorption and reducing operational costs. 

The two reagent powders are mixed and introduced to the system using a dosing screw conveyor & rotary valve. The dosing station was installed in its own purpose built housing, incorporating additional storage facility for the 1m³ bulk bags. The system works on a recipe system where each furnace operator selects the batch to be melted and the dosing system automatically adjusts the required levels of reagent cocktail to achieve the correct additive mixture to meet the required emmission levels. 

The main ID fan (110kW) was inverter controlled to achieve flow rates with greater efficiency. The fan was supplied with sound attenuation to reduce pollutant noise levels. The waste air is discharged to atmosphere via the 22m high exhaust stack. 

Each furnace, quench pump control station & injection system were fitted with their own individual HMI control panels communicating via Ethernet back to the main control panel PLC, which also has its own dedicated control HMI, where additional parameters can be adjusted, which is located in its own air conditioned control room. 

Particulate emission to atmosphere was guaranteed to 5.0 mg/Nm³ dry the measured emissions after commissioning was <1.0 mg/Nm3. Emission Guarantees were also given for SO2, HF , HCl & Dioxin Concentrations which were also achieved.