Abstract: To improve slag quality, on a fired grate, at the end of the main combustion process, where burnable fractions are still present in addition to slag components which are already forming, the burnup rate or burnup intensity is changed by varying the primary air rate in sequential time sections, the time sections preferably being in a ratio of 1:1 and the reduced primary air rate being 50 to 70% of the standard primary air rate.

Abstract: In order to carry out the method for controlling the firing rate of the combustion installation, the fire grate is equipped with a plurality of undergrate zones. In order to determine the control signal, the undergrate zone at the beginning of the main combustion zone is equipped with the corresponding measurement devices, namely a temperature sensor and a pressure sensor and the associated air supply line is equipped with an airflow measuring device. A further pressure sensor is provided in the furnace space so that the static pressure difference between the undergrate zone and the furnace space can be determined. The measured values from this measurement equipment are supplied to a central computer ZR which outputs, if necessary taking account of a flow coefficient .alpha.

Abstract: In order to remove deposits in feed nozzles (20), which serve to recycle exhaust gas into the furnace of a firing installation, a lance (27) can be inserted into the feed nozzles (20) and is held in such a way as to be displaceable in its longitudinal direction. The lance (27) has a nozzle head (28) at its front end for the spraying of water and is connected at its rear end to a valve device (29), which can be adjusted via a control device (32) with regard to the water quantity, the water pressure and the opening and closing times. By means of the lance (27), water is sprayed in a finely distributed manner onto deposits (34) in the interior of the feed nozzle (20), as a result of which the water penetrates into these deposits and causes these deposits to be blasted off due to the development of vapour.

Abstract: To detect a regulating quantity which is directly proportional to the combustion temperature, an infrared measuring device in the form of an infrared pyrometer is provided in the descending waste gas flue of an incineration plant and measures the temperature of the waste gases. The influence of radiation from the glowing fuel bed or the flame is excluded by arranging this measuring device in the descending waste gas flue. The temperature-dependent regulating quantity which is determined in this way can be used directly or indirectly to influence the combustion process. In a preferred application, the temperature-dependent regulating quantity serves to influence the supply of fuel and the speed of the combustion grate, while a regulating quantity derived from the mass flow of steam serves to influence the supply of primary air.