DE3045730A1 - Plant atmos. made inert by IC engine exhaust - to reduce danger of dust explosion - Google Patents

Abstract

A gaseous atmos. esp. inside coal grinding plant, is made safer by feeding into the plant the exhaust gases from an IC engine, possibly in conjunction with those from a separate combustion process. The IC engine may be supplied with gas contg. less O2 than needed for normal efficient operation. Gas from the plant may be used to supply O2 for the engine, which may produce electrical or mechanical power for use in auxiliary equipment. Arrangement prevents formation of explosive gas mixt. with coal dust. The exhaust gases from IC engine and further combustion process can be used alternately or simultaneously depending on conditions, e.g. the former can be added for peak demands detected by a sensor.

Description

Method and device for inerting the

System gases of a plant The invention relates to a method for inerting a gas atmosphere within a system, in particular a Coal grinding plant. The invention also relates to a device for performing it this procedure.

Process and devices for inerting an ignitable fuel / oxygen mixture within a coal grinding plant are known from DE-OS 28 49 432, for example. This is within the gas circuit of an air flow grinding system, namely in An additional burner in the area of a lifting air line leading to the mill discharge arranged. Before commissioning this coal grinding plant and during operation, namely when the oxygen content measured in the gas circuit of the mill has a exceeds a certain value, the burner is activated, which by mixing the oxygen-containing, circulating mill gases with fuel as well as the following combustion the oxygen content in the gas cycle to a tolerable level Level lowers.

Furthermore, from DE-OS 28 53 031 an air flow grinding system is known, in which the exhaust gases from a furnace are fed to a central inert gas collecting chamber from which numerous branch lines to all the points in the grinding system lead to which air in) smells are to be expected. In this gas mess room a constant pressure is maintained with the help of a control device.

The furnace is also on the flue gas side with the inlet area the mill in connection. Partial load operation or shutdown of the furnace triggers via a pressure switch that works in the area of the central inert gas collecting tank the automatic start-up of an auxiliary burner, which then supplies the inert gas of the entire system.

These known inerting methods and devices are thus in common that the exhaust gases from burners are always used to generate inert gas will.

It is therefore the object of the invention to these known inerting methods and devices to further improve, in particular in terms of application technology. These The object is achieved in that in the system at least the exhaust gases of an internal combustion engine are introduced. The process in an internal combustion engine delivers in addition to those for the method according to the invention desired exhaust gases also mechanical, especially kinetic energy, which at numerous individual aggregates present in a coal grinding plant are used can. In this way one finds its way through in relation to the mere exhaust gas generation Combustion More versatile use of the energy chemically bound in the fuel instead of.

In an advantageous embodiment of the invention, the system in addition, the exhaust gases of a further combustion process are fed. The exhaust gases the internal combustion engine can thus both alternatively and simultaneously are fed to the system with the exhaust gases from a further combustion process.

Regarding the quantitative allocation to the individual combustion processes numerous variations are possible.

For example, there may be a basic need for inert gases from another combustion process arise during a short-term peak demand from an internal combustion engine is covered.

In a further embodiment of the invention, the internal combustion engine with a low oxygen content in relation to optimal performance the combustion air operated. Since when using the internal combustion engine according to the invention Energy generation is not in the foreground, this can result in a loss of performance can be bought within wide limits. For example, a l) ieselll) otor with values of less than 8 vol. UL. Oxygen content of the intake manifold Gases can still be operated, although 4% by volume is the absolute lowest limit must be viewed.

In another embodiment of the invention, system gases are the System as an oxygen carrier for the combustion process in the internal combustion engine used. In this way it is possible to remove the system gases from the system branch off completely or partially and after going through the thermal process in feed the internal combustion engine back into the system, whereby the there Oxygen content is lowered. The gas routing of the internal combustion engine is as far as fully integrated into the system.

Imine device for carrying out the invention Procedure is shown in the% eicllrlullg itili, 'iticl of an air-flow grinding plant for coal.

Specifically, (1) denotes a tube mill and (2) an air flow classifier, its semolina discharge (3) via a conveyor unit (4) to a double pendulum sluice (5), which is connected to the mill input (6).

With (7) a raw coal bunker is designated, which has another conveyor unit (8) is also connected to the double pendulum sluice (5).

The fine material fraction of the classifier (2) arrives via a line (9) in a separator (10), in which it is separated from the mill gas and after passing through it a rotary valve (11) is discharged as fine coal. The exhaust pipe (12) the separator (10) is connected to the suction side of a fan (13), which communicates on the pressure side with a branch point (14). Not by means shown shut-off devices, which are arranged in branch lines (15) and (16), can be any quantity distribution of the starting from the branch point (14) entire mill gas flow can be made on these two branch lines. That Mill gas reaching the branch line (15) is after dedusting in an electrostatic precipitator (17) over a chimney (18) discharged into the open, with the in the Electrostatic precipitator (17) accumulating dust in the finished product in the raw coal bunker (7) (7) can be added.

The mill gas introduced into the branch line (16) flows into the Mill circuit consisting of tube mill (1); Air flow separator (2), conveyor unit (4) and double pendulum sluice (5) and is at a branch point (19) distributed on further branch lines (20) and (21). While the branch line (20) leads to the mill inlet (6), there is the branch line (21), also called the light air line called, with the mill outlet (6 ') in connection. The arrows on all as simple Lines of the lines shown indicate the direction of the respective material flow or gas flow.

With (22) is an internal combustion engine, e.g. a diesel engine numbered, the output shaft via a coupling (23) with an electrical energy generator (24) is in connection. The intake port of the diesel engine (22) is designated by (25), which in the embodiment shown via a connecting line (26) to the Branch line (16) is connected, but practically c'li all one be animated Steep of the mill gas circuit described can be appropriate. Via this connection line (26) is at least part of the circulating oxygenated System gases branched off and used as oxygen carriers to the thermal process in the diesel engine (22) supplied. It is useful, especially when the oxygen content is very low of the system gases to the outlet connection (25) a further oxygen-containing gas To maintain stable operation of the diesel engine (22). on however, a graphic representation of the additional equipment required for this is provided been waived. The exhaust gases from the diesel engine (22) pass through a line (27) to a branch point (28) and via a branch line (29) to the mill inlet (6). In the mill system described, they serve to render the circulating water inert System gases, however, can also be used for pre-inerting when the Koh ienm'hl tni ig <are used.

As an alternative to or at the same time as the exhaust gases from the diesel engine (22) can also connect to the mill system via a branch line (30) via the branching point (28) to the mill inlet (6) guided exhaust gases of another, shown schematically Combustion system, which is designated by number (31), are supplied. Included is also the representation of shut-off devices for reasons of drawing simplicity in the course of the branch lines (30) and (27) have been omitted.

An expediently used one is also not shown Measuring system for determining the instantaneous gas composition in the mill system, thus proceeding from a desired composition via appropriate control elements a quantitative regulation of the required emptying, exhaust gases, in particular the connection or disconnection of one of the two branch lines (30) or (27) or the diesel engine (22) can be initiated.

It is of particular advantage in the method according to the invention that In the case of inert gas generation, mechanically usable energy is also obtained, which over the energy generator (24) is converted into electrical energy and in this form can be used in numerous units of the coal grinding plant, e.g. in the case of the conveying units, (: blowing, etc .. The inert gas generator can do a lot here are advantageously used at the same time as an emergency generator, so that at Power failures mean safe shutdown or maintenance the operation of the coal grinding plant is made possible without it at any point the formation of explosive coal dust-air mixtures occurs.

Claims (6)

Patentan.spruche 1. Method for rendering a gas atmosphere inert within a plant, in particular a coal grinding plant, characterized in that that at least the exhaust gases from an internal combustion engine (22) are introduced into the system will. 2. The method according to claim 1, characterized in that the plant In addition, the exhaust gases from a further combustion process are fed. 3. The method according to claims 1 or 2, characterized in that that the internal combustion engine (22) based on an optimal performance Operation is operated with low oxygen content. 4th Method not according to claim 3, characterized in that system gases the system as an oxygen carrier for the combustion process in the internal combustion engine (22) can be used. 5. Device comprising a plant, in particular a coal grinding plant, characterized in that at least one internal combustion engine (22) is on the exhaust side with the system in connection. 6. Apparatus according to claim 5, characterized in that the internal combustion engine (22) is coupled to an electrical energy generator (24).