Method and apparatus for measuring and controlling efficiency of a combustion

Claim 1

A method for measuring the efficiency of a coal combustion by analysis of an ash sample drawn from a region of a coal combustion plant in order to analyze a property of the ashes related to the unburnt carbon content in said ashes, which comprises: a) drawing the ash sample to be analyzed from a region of a coal combustion plant and conveying said sample to a filter-support in a reaction cell hermetically sealed under controlled pressure; b) exhausting said reaction cell; c) supplying combustion reaction gas under controlled pressure into said reaction cell; d) projecting on a surface of said sample a laser beam of sufficient kind and power to be absorbed by said sample and to heat a superficial layer of said sample to the carbon combustion temperature or higher; e) withdrawing the gas present in said reaction cell, which includes CO 2 produced from combustion of said superficial layer of said sample and O 2 present in the combustion reaction gas but not taken up by the combustion, into a first or second calibrated detector; f) either, measuring in said first calibrated detector the amount of CO 2 in the gas withdrawn from said reaction cell or, optionally, measuring in said second calibrated detector the amount of O 2 in the gas; g) estimating the amount of unburnt carbon in said sample by comparison of the amount of CO 2 or O 2 in said withdrawn gas with the amount of CO 2 or O 2 measured from carrying out the above steps a)-e) on a sample of a known amount of unburnt carbon, the amount of unburnt carbon being an indicator of the efficiency of the combustion.

Claim 2

A method for measuring the efficiency of a coal combustion by analysis of an ash sample drawn from a region of a coal combustion plant in order to analyze a property of the ashes related to the unburnt carbon content in said ashes, which comprises: a) drawing the ash sample to be analyzed from a region of a coal combustion plant and conveying said sample to a filter-support in a reaction cell hermetically sealed under controlled pressure; b) exhausting said reaction cell; c) supplying combustion reaction gas under controlled pressure into said reaction cell; d) projecting on a surface of said sample a laser beam of sufficient kind and power to be absorbed by said sample and to heat a superficial layer of said sample to the carbon combustion temperature or higher; e) withdrawing the gas present in said reaction cell, which includes CO 2 produced from combustion of said superficial layer of said sample and O 2 present in the combustion reaction gas but not taken up by the combustion, into a first or second calibrated detector; f) either, measuring in said first calibrated detector the amount of CO 2 in the gas withdrawn from said reaction cell or, optionally, measuring in said second calibrated detector the amount of O 2 in the gas; g) estimating the amount of unburnt carbon in said sample by comparison of the amount of CO 2 or O 2 in said withdrawn gas with the amount of CO 2 or O 2 measured from carrying out the above steps a)-e) on a sample of a known amount of unburnt carbon, the amount of unburnt carbon being an indicator of the efficiency of the combustion.

Claim 8

An apparatus for measuring the efficiency of combustion in a coal combustion plant, said apparatus comprising: a device in flow communication with a reaction cell and constructed so as to be capable of connecting to the combustion plant for drawing ash samples from a region of the plant and transporting the samples to said reaction cell; said reaction cell constructed so as to be sealed in order to form a controlled pressure space inside thereof and comprising a filter-support for supporting the ash samples supplied from said device, an aperture positioned on said reaction cell for passing a laser beam onto said filter-support, a baffle plate constructed so as to be movable between a closed an open position located between said aperture and said filter-support, wherein said aperture is sealed by a plate of material constructed so as to allow the laser beam to pass therethrough and said baffle plate is in a closed position when the ash samples are transported to said reaction cell; means for heating said reaction cell in order to remove humidity contained in the ash samples; a combustion reaction gas source in flow communication with the inside of said reaction cell and constructed so as to supply a controlled amount of reaction gas under controlled pressure; a laser source constructed so as to generate the laser beam; means for directing the laser beam on a surface of the ash sample positioned on said filter-support in order to combust any carbon contained in a superficial layer of the sample with the reaction gas thereby generating an amount of carbon dioxide or oxygen gas or a mixture thereof; means in flow communication with a detector and said reaction cell for exhausting said reaction cell of said carbon dioxide and oxygen gas and transporting the gas to said detector; said detector in flow communication with said reaction cell and calibrated so as to measure the amounts of one or more of the carbon dioxide and oxygen gas generated from said combustion; an ejector constructed so as to remove the ash samples from said reaction cell after combustion.

Claim 9

An apparatus for measuring the efficiency of combustion in a coal combustion plant, said apparatus comprising: a device in flow communication with a reaction cell and constructed so as to be capable of connecting to the combustion plant for drawing ash samples from a region of the plant and transporting the samples to said reaction cell; said reaction cell constructed so as to be sealed in order to form a controlled pressure space inside thereof and comprising a filter-support for supporting the ash samples supplied from said device, an aperture positioned on said reaction cell for passing a laser beam onto said filter-support, a baffle plate constructed so as to be movable between a closed an open position located between said aperture and said filter-support, wherein said aperture is sealed by a plate of material constructed so as to allow the laser beam to pass therethrough and said baffle plate is in a closed position when the ash samples are transported to said reaction cell; means for heating said reaction cell in order to remove humidity contained in the ash samples; a combustion reaction gas source in flow communication with the inside of said reaction cell and constructed so as to supply a controlled amount of reaction gas under controlled pressure; a laser source constructed so as to generate the laser beam; means for directing the laser beam on a surface of the ash sample positioned on said filter-support in order to combust any carbon contained in a superficial layer of the sample with the reaction gas thereby generating an amount of carbon dioxide or oxygen gas or a mixture thereof; means in flow communication with a detector and said reaction cell for exhausting said reaction cell of said carbon dioxide and oxygen gas and transporting the gas to said detector; said detector in flow communication with said reaction cell and calibrated so as to measure the amounts of one or more of the carbon dioxide and oxygen gas generated from said combustion; an ejector constructed so as to remove the ash samples from said reaction cell after combustion.