Abstract: A primary air system for a combustion plant provides a flow of primary air to at least one coal pulverizer, which emits pulverized coal in a downstream direction to a furnace. The primary air system includes a first primary air line for feeding hot primary air to the coal pulverizer and a second primary air line for admixing of cold primary air into the hot primary air line at a mixing location positioned upstream of the coal pulverizer. A control system shuts off the flow of primary air to the coal pulverizer, when the coal pulverizer is being repaired or serviced while the furnace is in operation. The control system includes a first flow control butterfly valve disposed in the first primary air line at a position upstream of the mixing location and a second flow control butterfly valve disposed in the second primary air line at a position upstream of the mixing location.

Abstract: A power plant which combusts fossil fuel and biomaterial or waste includes a large boiler plant having at least one device for the combustion of fossil fuel. At least one additional combustion device is connected to the large boiler plant via at least one connection channel. The additional combustion device includes a grate hearth for the combustion of biomaterial or waste. The additional combustion device includes at least one heat exchanger device which is integrated into the water/steam circuit of the large boiler plant.