80 GHz Level Radar Solution Helps Recycle APC Residue Into Concrete Blocks
Another success for high frequency contactless radar level sensors
Castle Environmental is a leading supplier of specialist waste treatment, recycling and disposal services, handling in excess of 250,000 tonnes of waste each year. They operate three fully permitted sites in the UK and are proud to be ISO 14001 and ISO 9002 accredited.
They are dedicated to reducing reliance on landfill through the development of sustainable waste treatment and recovery methods. One type of waste processed at their Cardiff site is APCr (Air Pollution Control residue), the fine powder that remains following the cleaning of gases from Energy from Waste facilities. It contains lime which is alkaline, and consequently APCr is classified as hazardous waste.
For the past 18 months Castle have used recycled APCr as an aggregate replacement in the production of precast concrete products. Following a detailed end of waste review in full consultation with Natural Resources Wales (NRW), APCr is gainfully employed in the manufacture of a range of concrete blocks.
The pre-processed APCr is combined with additional aggregates and cement to produce heavy duty interlocking concrete blocks and 4” dense blocks, which are used in construction, civil engineering projects, barriers and bay walls.
(See fig 1) Now that APCr can be recycled as an alternative to landfilling the waste, the resultant concrete products mark a huge step forward in Castle Environmental’s plans to be the leading recycler of APCr in the UK.
Part of this recycling process involves mixing the APCr powder with recycled water in a 4m high agitated vessel to form a slurry which is then dewatered prior to combining with other aggregates to form the blocks.
During this mixing process, the level in the vessel requires careful monitoring and control to ensure the process is carried out under the correct conditions.
Inside the vessel there is a very agitated surface, solids can build up on the walls as well as the agitator itself and surface foam can also be produced under certain conditions. (See fig 2)
All these difficult conditions; the uneven surface, foam and solids build up – are accommodated by the VEGAPULS 64’s 80 GHz radar technology to deliver accurate and reliable level readings. It employs focusing to avoid unwanted interfering signals combined with high sensitivity to read through condensation, sensor build up and to overcome the foaming surface.
This technology is overcoming the ‘Laws of Physics’ that imply the higher the frequency, the more it can be affected. Through latest generation components, enhanced design and software it is taking sensitivity to astonishing performance levels, VEGAPULS 64 radar copes with these challenges and many others. 80 GHz contactless radar is offering new solutions to level measurements that were previously thought impossible with a contactless device.
As well as handling difficult conditions such as these, they are also capable of measuring very low reflectivity hydrocarbons, even liquid gases, highly pure solvents, past complicated vessel internals, down long nozzles and even operating through process isolation valves.
VEGA Controls Ltd
Kendal House, Victoria Way, Burgess Hill, West Sussex, RH15 9NF
Tel: 01444 870055
Fax: 01444 870080
info.uk@vega.com
www.vega.com/en
