DEVELOPMENTS IN CLEANING COKE OVEN DOORS Paul H. Donnan Jetin Sullair Inc. 5131 N.E. Union Avenue Portland, OR 97211 SUMMARY This paper will report on the work carried out over the last eight years on cleaning coke oven doors by using high pressure water jets. On a coking plant the doors are regularly removed to enable the re-charging process to take place. The doors have to be cleaned within one and a half minutes during the "pushing cycle". Buildup of hard carbonaceous, bitumastic layers on the doors and seals prevent easy removal and replacement. Additional benefits of clean door seals are the prevention of polluting the surrounding area, and a lessening of health hazard to the coke oven operators. Investigation into optimizing the cleaning operation will be reported. INTRODUCTION Coke is used in the iron making processes and to make the coke, coal is baked in ovens for about 18 hours. The gases released from the coal are used for firing the steel furnaces. There are many by-products, such as tar, benzine and the residue coke is discharged, and cooled, prior to being fed into the hungry blast furnaces, as required, for the steel making processes. The ovens used for coke making are up to 10 meters high, 0.5 meters wide and 30 meters deep. In a large coking plant there are several batteries and each battery comprises 50 ovens (see figure 1). The charge of coal is fed into the top of the ovens and after cooking for about 18 hours, vertical doors placed at each end of the oven are removed, the red hot coke is pushed through into specially built railway trucks. The coke is then cooled and then fed by conveyors directly to the blast furnaces. After the coke has been pushed through, the two doors are replaced. There has been an increasing problem with existing coking plants where the doors have suffered from fouling with tar deposits from the coal. During the 'cooking process', bitumen separates out mainly on the bottom of the oven and if there are any gaps in the door seal, coal tar oozes out of the door. One can imagine that with high narrow doors making a metal to metal seal is quite difficult if not impossible. Distortion of the doors is inevitable due to high temperatures in the oven. The doors are held onto the oven with two latching catches; as these are turned from the vertical to the horizontal, the latch tightens onto the door jamb, pushing it towards the oven. At times, it is impossible to get the door back onto the oven because of a buildup of bitumen on the faces, thus a spare door has to be collected from the end of
158