DD245473A1 - METHOD AND ARRANGEMENT FOR ELECTRICALLY TURNING A CARBON AIR COMPOUND - Google Patents

Abstract

The task is to finish the coal dust-air mixture provided by a coal mill without any further intermediate treatment and an additional ignition fuel and to start the steam boiler with the total mill output. This is achieved by heating an electrode in an alternating electrical field by vortex currents to their maximum temperature, then the coal dust-air mixture is supplied, the resulting fuel gases heated by further strengthening of the alternating electric field in the high frequency range up to a plasma-like state be increased and the supply of Kohlenstaubluft mixture. figure

Description

For this 1 page drawing

Field of application of the invention

The invention relates to a method and an arrangement for the electrical ignition of a coal dust-air mixture.

Characteristic of the known technical solutions

Large combustion plants, such as steam boilers in power plants, are ignited and / or operated with highly flammable fuels (oil or gas) or specially treated pulverized coal. The ignition of easily inflammable fuels takes place due to the required, relatively low ignition energy either by means of electrical sparks (DE 2531556) or direct or indirect electrical Widerstandsheizüngen (DD 224394, DE 3424272). Such ignition requires a large amount of gas or oil. In order to avoid having to use these high-quality primary energy sources for combustion purposes, it is becoming increasingly common practice to operate pilot burners with processed pulverized coal. A disadvantage of these ignition devices that the coal dust has diverted from the total flow of a coal mill and must be dried to ensure a certain minimum moisture with a high technological cost. The ignition of flame-retardant fuels, such as pit-lignite lignite coal, is already carried out via arcing arrangements. Due to the concentrated burning of the arc, the electrodes are subject to relatively high wear. Rigid electrodes must therefore be replaced often, for nachschiebbare electrodes a complicated drive mechanism is required.

Object of the invention

The aim of the invention is to reduce the cost of igniting a pulverized coal-air mixture.

Explanation of the essence of the invention

The invention has the object of providing the coal dust-air mixture provided by a coal mill without a further intermediate treatment and ignite without an additional ignition fuel and the entire mills power the steam boiler to approach.

This is inventively achieved in that an electrode is heated in an alternating electric field by eddy currents to their maximum temperature, then the coal dust-air mixture is supplied, the resulting fuel gases by further amplification of the alternating electric field into the high-frequency range up to a plasma state are heated and the supply of the coal dust-air mixture is increased.

The arrangement for carrying out the method is characterized in that a quartz tube is externally wound with a coil which is connected to a frequency generator and in the quartz tube, an electrode bundle is axially displaceable.

embodiment

The invention will be explained in more detail below using an exemplary embodiment. The accompanying drawing shows the arrangement for igniting the pulverized coal-air mixture.

A quartz tube 2 is externally wound with a coil 4. The coil 4 is connected to a frequency generator 3. In the quartz tube 2 is an electrode bundle 1, z. B. coal or tantalum, arranged axially displaceable.

The electrode bundle 1 is heated by the frequency generator 3 and the coil 4 to maximum temperature. Thereafter, a sufficient amount of a pulverized coal-air mixture 5 is blown from a coal mill into the quartz tube 2. The coal dust-air mixture 5 ignites and burns as a stable flame. The generator frequency is further increased up to the high-frequency range. Thus, the combustion gases are overheated by the frictional heat up to plasma temperatures. At the same time, the supply of the pulverized coal-air mixture 5 is further increased and the electrode bundle laus moved out of the quartz tube 2. By controlling the amount of coal dust-air mixture 5 and the RF energy, the heating power of the burner is set.

By means of the method according to the invention, a pulverized coal-air mixture 5 provided by a coal mill can be started up and operated without a further intermediate treatment and without an additional ignition fuel.

Claims (2)

Invention claim: 1. A method for the electrical ignition of a pulverized coal-air mixture, characterized in that an electrode is heated in an alternating electric field by eddy currents to their maximum temperature, then the coal dust-air mixture is supplied, the resulting fuel gases by further amplification of the alternating electric field are heated in the high frequency range to a plasma state and the supply of the coal dust-air mixture is increased. 2. Arrangement for carrying out the method according to item 1, characterized in that a quartz tube (2) is externally wound with a coil (4) which is connected to a frequency generator (3) and in the quartz tube (2) an electrode bundle ( 1) is arranged axially displaceable.