The Ougree Coke Works
The area where today’s coke works are located was purchased by the “Societe Anonyme John Cockerill” in 1882 and there have been several coke work incarnations since then. The current coke works were build in 1957, shortly after the “Societe Anonyme John Cockerill” merged with “Societe Anonyme Ougree-Marihaye” to form the “Societe Anonyme Cockerill-Ougree”. For a history of the “SA Cockerill” see Cockerill-Sambre, Ougree. The Ougree Coke Works were equipped with 4 Krupp-Koppers oven batteries, which were installed in 1967 and 1983 and totalled 139 ovens. In 2010 the number of ovens was increased to 185 due to the restart of the “Haut Fourneau B (HFB)” . At the height of its production the coke works produced 800000 tonnes of metallurgical coke per year. However, the HFB closed down for good in 2011, sealing the fate of the Ougree Coke Works, which closed their doors in 2014.
The Coal Silos
While some coal was delivered to the Ougree Coke Works by train, most of the it arrived by ship via the River Meuse, the port being located just outside the coke works. After having been unloaded, the coal was pulverised to a size of about 2mm before being transported to the coal silos by conveyors, which deposited the crushed coal in bins depending on its origin. This avoided coal with different chemical and physical properties being mixed. The two silos at Ougree had a total capacity of about 11000 tonnes. However, on average the silos never contained more than 15 days of coal supply, mainly because humidity impacted negatively on the quality of the coal.
Before leaving the coal silos, the crushed coal was mixed with oil and various by-products (such as naphtalene fuel), in order to render the coking process more efficient. This coal mixture was then transported to the charging tower for storage and further processing.
The Coal Mill
The Coke Batteries and Charging Tower
The coal that is used to produce coke is usually a blend of two or more low, medium, or high volatile coals which are normally low in sulphur and ash. Blending is usually needed to control the properties of the resulting coke, to optimize the quality and quantity of byproducts, and to avoid the expansion exhibited by certain types of coal that may cause excessive pressure on the oven walls during the coking process. This blending of the coal mixtures was done in the charging tower. Once the optimal blend is obtained, coke dust, petroleum coke and fuel oil were added before the mixture was discharged into the charging car, which travelled along the top of the battery along a set of rails. The Ougree Coke Works had two charging cars, one for each battery.
The coke ovens are the chambers made of refractories to convert coal into coke by carbonizing coal in absence of air and there by distilling the volatile matter out of coal. A coke oven plant consists of one or more coke oven batteries each containing up to 100 of coke ovens. The coke ovens are charged through charging holes, which are located on top of the oven, next to the rails of the charging car. In order to charge the ovens, the charging car was positioned over the charging hole of an empty, hot oven (called ‘spotting’), the lids on the charging ports were removed, and the coal was discharged from the hoppers of the charging car into the oven.
The coking process (thermal distillation) takes place in groups of ovens called batteries. A battery consists of a number of adjacent ovens with common side walls that are made of high quality silica and other types of refractory brick. The wall separating adjacent ovens, as well as each end wall, is made up of a series of heating flues. At any time, half of the flues in a given wall are burning gas while the other half are conveying waste heat from the combustion flues to a ‘checker brick’ heat exchanger and then to the combustion stack. Gas is injected into the flues via fuel injectors that are located immediately below and on both sides of the coke ovens. Every 20 to 30 minutes the battery ‘reverses’, and the waste heat flues become combustion flues while the combustion flues become the waste heat flues. This process provides more uniform heating of the coal mass. The operation of each oven is cyclic, but the battery contains a sufficiently large number of ovens to produce an essentially continuous flow of raw coke oven gas. The individual ovens are charged and emptied at approximately equal time intervals during the coking cycle. Coking proceeds for 15 to 18 hours to produce blast furnace coke. During this period, volatile matter of coal distills out as coke oven gas. The coking time is determined by the coal blend, moisture content, rate of under firing, and the desired properties of the coke. When demand for coke is low, coking times can be increased to 24 hours. Coking temperatures generally range from 900 to 1100 deg C and are kept on the higher side of the range to produce blast furnace coke. The gases and hydrocarbons that evolve during the thermal distillation are removed through the off take system and sent to the byproduct plant for recovery.
At the end of the coking cycle, doors on both ends of the oven are removed and the incandescent coke is pushed from the oven by a ram that is extended from the pusher machine. The coke is pushed through a coke guide into a quenching car. The quenching car carries the coke to either a wet quenching tower where it is cooled.
The coking process produces coke oven gas (COG) which is unsuited for firing the coke oven batteries and for other applications, because of technical and environmental related. Coke oven gas contains various toxic and carcinogenic substances, such as benzene, toluene, amonia and hydrogen cyanide. Thus, it requires cleaning, which is done in the so-called by-product plant which comprises a complex chemical plant. The coke oven gas is extracted from the coke ovens by extractors which are situated on top of the ovens. During the extraction process the COG, which has a temperature of 1000 degree Celsius, is immediately quenched by direct contact with a spray of aqueous liquor (flushing liquor). The resulting cooled gas is water saturated and has a temperature of around 80 deg C. This gas is collected in the a large pipeline called the “coke oven battery gas collecting main”. The amount of flushing liquor sprayed into the hot gas leaving the oven chambers is far more than is required for cooling, and the remaining unevaporated flushing liquor provides a liquid stream in the gas collecting main that serves to flush away condensed tar and other compounds. At some stage the raw coke oven gas and the flushing liquor are separated and then flow separately to the byproduct plant for treatment.
The Power Station
This derelict power station was abandoned long before the Ougree Coke Works closed their doors, according to some sources sometime before 2000. This power plant probably provided electricity to the Ougree Coke works before the expansion of the power plants at the HF6 Serraing and HBF Ougree.