Knostrop Clinical Waste Incinerator: Difference between revisions

The two incinerators are of stepped hearth design, with three main combustion hearths and an ash box. [[Clinical Waste]] is loaded mechanically direct from the wheeled bins used to deliver the [[Clinical Waste|waste]], onto the first hearth, and the [[Combustion|combustion]] process commences. Hydraulic rams operate at intervals to push the [[Clinical Waste|waste]] along the first hearth, until it falls off the end onto the second hearth where the [[Clinical Waste|waste]] burns vigorously at a temperature of between 1000 and 1100 degrees Centigrade. The [[Clinical Waste|waste]] is then pushed from the second hearth onto the third hearth, where it burns out to produce an ash. This bottom ash is then pushed into an ash box, where the fixed carbon in the ash is further burned out. The retention time on the hearths is approximately 12 hours, with the bottom ash being retained in the ash box for up to 8 hours before being dropped into a skip. Ram movements are programmed in relation to the number of bins fed.

The flue gases are then cooled by passing through a waste-heat boiler and economiser, before passing into the final, abatement section of the process. Powdered [[Wikipedia:Lime (material)|lime]] (Calcium Hydroxide) and powdered [[wikipedia:Activated carbon|activated carbon]] are added to the flue gases entering the abatement process to remove acid gases, heavy metals and residual [[Wikipedia:Dioxins and dioxin-like compounds|dioxins]] and [[Wikipedia:Furan|furans]] before discharge to atmosphere from the stack. The flue gases being discharged from the stack are continuously monitored for [[wikipedia:Hydrogen chloride|Hydrogen Chloride]], [[wikipedia:Sulfur dioxide|Sulphur Dioxide]], [[Wikipedia:Carbon monoxide|Carbon Monoxide]], [[Wikipedia:Nitrogen oxide|Oxides of Nitrogen]], particulate matter (dust), [[Wikipedia:Volatile organic compound|Volatile Organic Compounds]], [[Wikipedia:Oxygen|oxygen]] and [[Moisture Content|moisture content]].