SE443040B - POWDER CONDUCTING PLANT FOR A PROCESS Oven - Google Patents

Description

4 »- ...,., _ Rost. 8003445-7 2 air back into the mill system and serves as extra carrier air in the mill, while the rest together with the carbon dust separated in the cyclone is blown into the furnace. At high carbon humidity and at low-temperature mill heating, a larger amount of exhaust air is obtained from the drying than corresponds to the required amount of carrier air. In these cases, therefore, either a high amount of primary air must be purchased or an extra filter installed. This results in disadvantages such as direct and indirect fire. Thus, a high amount of primary air prevents the optimization of the blowing impulse conditions in the furnace burner and an extra filter means extra investment costs and an increased risk of coal explosions and fires. The object of the invention is therefore to provide a plant in which, regardless of the carbon humidity and the mill heating, the primary air portion can be freely selected small and the blowing conditions in the burner nozzle are adjustable regardless of the mill-drying process, without a special carbon filter or intermediate storage containers and the associated safety risks and additional costs, such as even in the case of an indirect plant, need to be taken into account and at which the heat and the mill air can be recovered.

This object is solved according to the invention by feeding a subset of the air from the separator to the process goods cooler.

Suitably, the subset of the separator air fed to the process goods cooler is fed into the front part of the process goods cooler. It is also suitable that the partial amount of the separator air fed to the process cooler is fed in via a process contained in the process cooler. It becomes possible to limit the proportion of primary air volume for the furnace burner independently of the grinding-drying system and the carbon humidity to the minimum required for optimal combustion. and at the same time energy-saving insert the remaining amount of mill air environmentally friendly without any special filter system. The plant according to the invention works energy-saving, since the heat from the hot mill air is reused for heating the secondary air.

Furthermore, the residual carbon dust of the mill air is supplied to the secondary air, so that it does not need to be filtered out; in particular, this residual carbon dust in the secondary air stream can be burned. This means a more direct and complete utilization of the entire carbon dioxide amount of the mill air, so that the plant according to the invention not only works to save energy or raw material but also to be environmentally friendly and cheaper, then residual POOR QUALIT? 8003445-7 the carbon dust is removed and consequently a special filter system is no longer needed.

In addition, due to the absence of a carbon intermediate container and the filter plant_and through the possibility to run and inactivate the associated grinding-drying plant even at high carbon humidities with low hot air temperatures, the plant according to the invention has a high safety against carbon explosions. and fires are guaranteed and even high carbon humidities can be easily overcome through the far-reaching use of the waste heat of the furnace and / or the tile cooler.

The plant according to the invention is explained with the aid of the attached drawing figure, which schematically shows how it works. According to the figure, the plant in particular comprises a cement kiln with a tile-sliding cooling radiator.

The coal dried and ground in a coal mill 1 is separated in a high-efficiency cyclone 2 and is trapped by a closing means 3 in the primary air stream and a partial air stream of the primary air 4, respectively.

The amount of gas or air required for drying and as carrier air is sucked with a system fan 5 through the coal mill 1 and the high-power cyclone 2. As transport medium and drying medium in front of the coal mill 1, either hot radiator air through the radiator air line 6 or hot furnace main air through the furnace main air duct 7 is used. the furnace exhaust line 8, hot gas from a combustion chamber 9 or combinations of radiator air, furnace main air, furnace exhaust gas and hot gas, whereby for the control the radiator air valve 10, the furnace air valve 11, the furnace exhaust valve 12 and the combustion chamber valve 13 and the cold air valve 30 are used. The carbonaceous mill air pre-repelled in the high-power cyclone 2 is divided behind the system fan 5 and can be transported both to the primary air fan 15, to the mill inlet over the connecting line valve 19 through the connecting line 18 or to a cooling air fan 16 of the clinker coolers of the different coolers 17. depending on the requirements of the mill system, carbon humidity and flame formation, the lengths can be optimized and adjusted within the range of 0 - 100% each. In addition, the connecting line valve 19, the cooling air supply valve 20 and the auxiliary valve 21 as well as the primary air valve 22 and the cold air mixing valve 23 serve.

Through these setting options, the proportion of primary air can be arbitrarily reduced and the most diverse burner nozzles 24 and combination burners, for example with additive fuel 36, are inserted, without having to take into account the coal moisture and the conditions at the grinding-drying plant. _ "_.-_-..... _ _ Poon QUALITY .., .- =. .Ee-.r-f fl _ f. .. f? N; 8003445-7 So, especially at high carbon humidities, a higher The blowing takes place, for example, with a corresponding cooling air fan 1ë, as shown in the figure, or, as not shown in the figure, directly into one of the cooling chambers 31. However, the blowing can also be divided into several cooling air fans 16 or even is conveyed with a separate cooling air supply fan 34 into one or more cooling air chambers 31 and directly to the hot air part of the tile cooler 37 over the grate 25. Preferably, however, the hot air part of the cooling air chamber 31, which is closest to the tile cooler 37 In addition, the non-thermal heating component still present in the mill air in the form of residual carbon dust during the passage through the hot clinker layer is thus ignited and utilized.This further heats the secondary air. the air is supplied to the exhaust air duster 27 via the exhaust air line 32 and is dusted in it. With the aid of the exhaust fan 28 and the control valve 29, the exhaust air is transported out into the open depending on the furnace head pressure.

In the plant according to the invention, in contrast to the indirect process, all exhaust air heat is recovered, ie both the thermal heat and also the heat present in the residual carbon dust of the exhaust air. In addition, no carbon filter is required due to the combustion of the residual carbon dust. This means a significant saving and increase in operational reliability. Consequently, no carbon dust is released into the free atmosphere, so that the plant according to the invention is significantly more environmentally friendly than hitherto known plants. No intermediate storage of carbon dust is required either, so that the risk of carbon fires and explosions is significantly reduced. Overall, of course, investment, care and operating costs are lower.

In contrast to direct and semi-direct procedures, the primary air volume can be chosen freely. Thus, an optimization of the flame is possible and the amount of primary air can be kept considerably smaller. This results in fuel savings, which at high carbon humidities can amount to up to about 100 kcal / kg clinker (0.42 fi J / h clinker).

POOR QUALITY

Claims (3)

8003445-7 P a t e n t k r a v: Powder firing plant for a process furnace, in particular for a cement clinker furnace, with grinding and drying of coal and feeding the used drying air from the coal mill (1) through a separator (cyclone Z), from which the separated coal powder is fed to powder burner (24) in the process furnace, the air from the separator (2) being used as primary air (through the valve 22) and possibly also as return air (through the valve 19) to the mill (1), and in which the process goods are cooled by means of fl. genuine air (from fans 16) and the used fan air is used as secondary air to the powder burners (24) and possibly also as drying air (through 14) during powder drying or as heating or cooling air, characterized in that a subset (via 34) of the air from the separator (2) is fed to the process goods cooler (17). Plant according to Claim 1, characterized in that the subset of the separator air supplied to the process cooler is fed into the front part of the process cooler (cooling air chambers 31). Plant according to Claim 1 or 2, characterized in that the subset of the separator air fed to the process goods cooler is fed in via a grate (25) included in the process cooler. LPOOR QUALIÉ t '