banneredit
3,643
edits
Knostrop Clinical Waste Incinerator: Difference between revisions
m
minor text change
(add page specific text) |
m (minor text change) |
||
| (10 intermediate revisions by 2 users not shown) | |||
| Line 6: | Line 6: | ||
==Summary== | ==Summary== | ||
[[Clinical Waste Incinerator]] operated by [[SRCL]] and located adjacent to Knostrop Treatment Works, Leeds, with an annual throughput limit of 17,000 tonnes. | [[Clinical Waste Incinerator]] operated by [[SRCL]] and located adjacent to Knostrop Treatment Works, Leeds, of a twin-line [[Grate|stepped hearth design]], with an annual throughput limit of 17,000 tonnes. | ||
==Plant<ref name="Adden">Annual Performance Report 2020</ref>== | ==Plant<ref name="Adden">Annual Performance Report 2020</ref>== | ||
The Leeds incinerator consists of two streams, known as the East and West streams, each with a nominal throughput of one tonne of [[Clinical Waste|clinical waste]] per hour. The [[Environmental Permit|permit]] sets an annual throughput limit of 8,500 tonnes on each stream, with lower limits on specific [[Waste|waste]] types. The two streams are independent of each other, so that one stream can still be operated while the other stream is shut down for maintenance. | |||
The two [[Incineration|incinerators]] are of [[Grate|stepped hearth design]], with three main [[combustion]] [[Grate|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 [[Grate|hearth]], and the [[Combustion|combustion]] process commences. Hydraulic rams operate at intervals to push the [[Clinical Waste|waste]] along the first [[Grate|hearth]], until it falls off the end onto the second [[Grate|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 [[Grate|hearth]] onto the third [[Grate|hearth]], where it burns out to produce an [[Incinerator Bottom Ash|ash]]. This [[Incinerator Bottom Ash|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 [[Incinerator Bottom Ash|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 from the [[Incineration]] process then pass through a secondary chamber, or afterburner, where any gaseous products of [[Combustion]] are burned out under oxygen rich conditions. This stage is designed to destroy any [[Wikipedia:Carbon monoxide|Carbon Monoxide]], [[Wikipedia:Volatile organic compound|Volatile Organic Compounds]], and [[Wikipedia:Dioxins and dioxin-like compounds|dioxins]] and [[Wikipedia:Furan|furans]] produced by the [[Combustion]] process. | |||
The [[Flue Gas|flue gases]] are then cooled by passing through a waste-heat boiler and [[wikipedia:Economizer| 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 Gas|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 [[wikipedia:Chimney|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]]. | |||
The [[Incineration|incineration]] process produces two residues; [[Incinerator Bottom Ash|bottom ash]] and [[Fly Ash|spent lime]]. The [[Incinerator Bottom Ash|bottom ash]] is sent to a recycling transfer station for reprocessing, the bulk of the material ultimately ending up as a [[Landfill|landfill]] cover material. The [[Fly Ash|spent lime]], which is the residue from the [[Flue Gas|flue gas]] abatement process, went to a site in Leeds where it is used to neutralise acidic wastes. | |||
{{EAIn|EPR={{#var:epr}}}} | {{EAIn|EPR={{#var:epr}}}} | ||
==References== | ==References== | ||