18 June 2002 – Since mad cow disease was identified in the mid 1980s, blamed on the use of meat and bone meal (MBM) in animal feed, the feed has been banned by the EU in order to eradicate the disease. Most European countries now require animal meal to be incinerated which means that new technology and larger industrial kilns are needed to cope with the volume.
Power plants and cement factories increasingly use secondary raw materials in the incineration process and have thus approached manufacturers of material handling equipment to develop technologies for unloading, storing and conveying the product. Taking on the task is Louise Fordertechnik, a subsidiary of the Aumund Group.
An issue when storing and handling MBM is its explosive nature due to the high content of volatiles, a result of the drying process. MBM also contains fat which makes the materials react differently to heat and cold. Stored in silos, it tends to stick to the silo walls when the fat melts during summer, or turns consistent during winter. Buffer silos need to be designed to isolate the product from extreme temperatures and the reclaim and conveying equipment must be able to cope with the sticky material.
Louise Fordertechnik has designed a compact unit incorporating truck unloading, storage, silo discharge and boiler feeding. Truck unloading is performed pneumatically by means of a compressor unit installed next to the silo supporting structure. The same compressor unit then pumps the meal into the buffer silo. The compressed air is continuously cooled to prevent the fat contained in the product from melting. Based on experience, residues from metal labels can from time to time be found in the animal meal. A meal separator is thus installed inside the pneumatic
conveying tube leading to the silo.