US 6,475,802 B2 · Apparatus for and method of collecting gaseous mercury and differentiating between different mercury components

Abstract

A method and apparatus are provided for collecting a sample gaseous mercury, to differentiate between different gaseous mercury components. A quartz denuder module is provided having a coated extended surface for adsorbing reactive gaseous mercury. After collection of a sample, the coating it is heated to desorb the mercury as elemental gaseous mercury, which can then be detected and measured in conventional analyzer. During the sampling phase, as reactive gaseous mercury is removed from the sample flow in the denuder, the sample can then be passed to the analyzer for detection of elemental gaseous mercury. Where particulate mercury may be present, a filter trap can be provided downstream from the denuder. Separate steps can be provided for heating and pyrolysis of particulate mercury, for separate measurement in the analyzer. The pump module can be configured to a past the gas sample through scrubbers, to generate zero air as a flushing gas. The denuder can be mounted in separated module, so that it can be mounted in desired external location, remote from other instrumentation.

Claims50

Dependent claims

A speciation module for repeated speciation of reactive gaseous mercury from elemental mercury and particulate bound mercury and for use with mercury analysis equipment, the speciation module comprising:

an adsorption unit having an extended transfer surface and a coating including a halogen salt on the transfer surface for adsorbing reactive gaseous mercury and allowing elemental mercury and particulate bound mercury to pass through the adsorption unit, the adsorption unit having an adsorption unit inlet opening directly to a gas sample and an adsorption unit outlet for connection to a pump means, for drawing the gas sample through the adsorption unit, and being formed of a material capable of withstanding a desorption temperature;
a first inlet for a flushing gas, substantially free of mercury vapour, for flushing out of the adsorption unit and connectable to the adsorption unit inlet;
a heating means for heating the adsorption unit to the desorption temperature higher than an adsorption temperature, the desorption temperature being such as to cause reactive gaseous mercury adsorbed onto the coating to be released as gaseous elemental mercury vapour, for measurement, and such as to regenerate the coating on the transfer surface to facilitate repeated speciation;
and,
a temperature controller for controlling the heating means, whereby the adsorption unit can be maintained at the adsorption temperature for adsorption of the reactive gaseous mercury and, at the desorption temperature for desorption of the reactive gaseous mercury as gaseous elemental mercury vapour.

2 more elements

An apparatus for use with a mercury analyzer for the repeated speciation of reactive gaseous mercury, the apparatus comprising:

(1) an adsorption unit having an extended surface and a coating a halogen salt on the extended surface for adsorbing reactive gaseous mercury and allowing elemental mercury and particulate bound mercury to pass through the adsorption unit, the adsorption unit having an adsorption unit inlet opening directly to a gas sample and an adsorption unit outlet and being formed of a material capable of withstanding a desorption temperature;
(2) a heating means for heating the adsorption unit to the desorption temperature higher than an adsorption temperature, the desorption temperature being such as to cause reactive gaseous mercury adsorbed on the coating to be desorbed and vaporized as elemental mercury vapour and such as to cause the coating on the extended surface to regenerate to facilitate repeated measurements;
(3) a temperature controller for controlling the heating means, whereby the adsorption unit can be maintained at the adsorption temperature for adsorption of the reactive gaseous mercury and, at the desorption temperature for desorption;
(4) a pump means connected to the adsorption unit outlet for drawing the gas sample through the adsorption unit;
and,
(5) a flushing gas supply means for supply of a flushing gas and connectable to the adsorption unit inlet, for passing flushing gas through the adsorption unit, whereby in use, the gas sample is drawn through the adsorption unit by the pump means in a sampling phase and reactive gaseous mercury is adsorbed onto the coating of the adsorption unit, and in a desorption phase, the heating means is actuated and flushing gas is passed through the adsorption unit from the adsorption unit inlet to the adsorption unit outlet so that adsorbed reactive gaseous mercury is desorbed as elemental mercury vapor-and entrained in the flushing gas flow.

3 more elements

A method for speciation of reactive gaseous mercury from elemental mercury and particulate bound mercury in a gas sample and measurement of the reactive gaseous mercury, the method comprising the steps of:

(1) passing the gas sample through an adsorption unit having an adsorption unit inlet opening directly to the gas sample and an adsorption unit outlet and being capable of withstanding a desorption temperature, said adsorption unit having an extended surface provided with a coating for adsorbing reactive gaseous mercury and allowing the elemental mercury and the particulate bound mercury in the gas sample to pass through the adsorption unit, the adsorption unit being maintained at a suitable adsorption temperature above ambient temperature of the gas sample to prevent condensation of water vapour during adsorption;
(2) after a known quantity of the gas sample has been passed through the adsorption unit, terminating supply of the gas sample, and passing a flushing gas through the adsorption unit;
and
(3) while passing the flushing gas through the adsorption unit, heating the adsorption unit to the desorption temperature higher than the adsorption temperature, to cause desorption of reactive gaseous mercury compounds as gaseous elemental mercury vapour for entrainment in the flushing gas and to regenerate the coating of the adsorption unit to facilitate repeated mercury speciation without significantly compromising the coating, and passing the flushing gas with the entrained gaseous elemental mercury vapour to a mercury analyzer for determination of the level of the reactive gaseous mercury in the gas sample.

1 more element

Dependencies are inferred from the claim text.

Apparatus for and method of collecting gaseous mercury and differentiating between different mercury components

Life of this patent

Apparatus for and method of collecting gaseous mercury and differentiating between different mercury components

Life of this patent

Abstract

Claims50