Electricity: measuring and testing – Impedance – admittance or other quantities representative of... – Distributive type parameters
Patent
1997-08-11
2000-03-14
Brock, Michael
Electricity: measuring and testing
Impedance, admittance or other quantities representative of...
Distributive type parameters
324 714, 73 3402, 73 2403, G01N 3153
Patent
active
060377836
DESCRIPTION:
BRIEF SUMMARY
The invention relates to a method for determining the charging of a gas stream with solid fractions, in particular for regulating the firing of a boiler with coal dust in a coal-fired power station, and to a device for this purpose.
In many sectors of industry, it is necessary to transport solid fractions by means of a gas stream. In the present case, the primary concern is to measure and regulate the supply of coal dust to the boiler of a coal-fired power station. However, this is to be merely a preferred exemplary embodiment of the present invention.
In coal-fired power stations known at the present time, coal dust is fed by carrier air to corresponding burners which are arranged at different levels in a boiler. Furthermore, combustion air also enters the boiler and assists the combustion of the coal dust in the boiler.
For the purpose of setting the quantity of coal-dust particles which is supplied, flaps, distributors or such actuating members are employed in a corresponding, feed conduit, these being set once, namely on the commissioning of the coal-fired power station, and then remaining in this position for a relatively long period of time.
Sampling from the feed stream is then carried out at specific periods for the purpose of resetting the firing. An incorrect setting of the firing is not recognized because, at the present time, the quantity of coal-dust particles can be measured only discontinuously. However, the supply of an incorrect quantity of coal-dust particles to the boiler has a highly adverse effect. On the one hand, the efficiency is appreciable lowered and, on the other hand, the waste gas values are increased. Furthermore, as a consequence of an incorrect quantity of coal-dust particles, the boiler and also the burner are subject to increased wear.
The use of measuring instruments in the feedstream itself would also be conceivable, but the disadvantage of this is that the feedstream is contracted in the region of the measuring instrument, so that pressure losses or abrasion occur here. Both are undesirable.
The object on which the present invention is based is to develop a method and a device of the above-mentioned type, by means of which a continuous determination of the solid fractions in a gas stream becomes possible in a simple manner, without this gas stream being in any way impaired.
To achieve this object, electromagnetic waves are sent from a transmitter to a receiver through the gas stream having the solid fractions, and the attenuation of these electromagnetic waves as a result of the absorption of some of them on the solid fractions is determined.
The great advantage of this method is, on the one hand, that it is possible continuously to subject the gas stream having the solid fractions to the electromagnetic waves. Continuous measurement of the solid fractions may accordingly take place. Furthermore, there is no need, for example in a sensor tube, for mechanical fittings which lead to the above-mentioned disturbance of the gas stream.
The invention makes use of the advantage of electromagnetic waves that parts of these electromagnetic waves are reflected and absorbed on solid fractions. That is to say, these parts do not arrive at the receiver, so that a considerable difference is detected between the electromagnetic waves transmitted and those received. The charging of the gas stream with solid fractions can be deduced from this difference, this, of course, initially being only of relative value. Evaluating the relative measurement by means of a correcting factor gives an absolute measurement.
This could be carried out, for example, as follows: conveyor, by means of which coal is fed to a mill for the production of coal dust. This can take place by means of commercially available measuring systems, for example by means of a radiometric conveyor weigher. burner conduits or the sensor tubes is formed, in order thereby to determine the total throughput capacity and/or quantity. relative measurement of the coal-dust stream is calculated from: ##EQU1##
Each measured value is e
REFERENCES:
patent: 4512200 (1985-04-01), Ghering et al.
patent: 4566321 (1986-01-01), Zacchio
patent: 4718269 (1988-01-01), Der Kinderen
patent: 4726235 (1988-02-01), Leffert et al.
patent: 5341101 (1994-08-01), Maerefat et al.
patent: 5502393 (1996-03-01), Yamaguchi et al.
patent: 5550537 (1996-08-01), Perdue
patent: 5581191 (1996-12-01), Yamaguchi
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