US 6,386,014 B1Granted

Energy measurement device for flowing gas using microminiature gas chromatograph

AssigneeEagle Research Corporation

InventorJames N. Butch

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Abstract

A system for determining the energy and volume delivered by a flowing natural gas carried within a pipeline based on BTU content analysis of the natural gas using a micro-miniature gas chromatograph. By monitoring key parameters of the flowing natural gas, such as temperature, pressure, flow rate, and BTU content, the system 110 accurately determines the total energy and total volume delivered by the flowing natural gas over a programmable duration of time. Micro-miniature fabrication of the gas chromatograph imparts important advantages to the system 110, including small size, modular design, low power consumption, fast BTU analysis times, and low consumption of consumable carrier and reference gases. Low power consumption permits operation of the system 110 using low-capacity supplies such as solar or battery, while minuscule consumption of consumable gases permits the use of 100 ml or less cartridges for the carrier and reference gases, making the integration of the consumable gas cartridges into the system 110 enclosure practical. A further advantage of the micro-miniature gas chromatograph as used in the system 110 is its modular design, allowing convenient disposal and replacement. The foregoing attributes combine to provide an energy monitoring system that, due to its small size, low operating power, and low consumption of consumable gases, is ideally suited for unattended operation for extended periods of time.

Claims37

Dependent claims

An apparatus for monitoring an energy value for a flowing gas comprising:

a flow monitor for measuring a flow rate of the flowing gas;
a micro-miniature gas chromatograph for detecting an amount of a constituent bearing on energy content of the flowing gas comprising:
i. a micro-capillary injection chamber in selective fluid communication with an inert carrier gas and a sample of the flowing gas for mixing the carrier gas and the sample into a gas mixture,
ii. a micro-capillary separation column for separating the constituent from the gas mixture having a first opening in fluid communication with said injection chamber for receiving the gas mixture and a second opening for exhausting the constituent separated from the gas mixture,
iii. a detector in fluid communication with said second opening of said separation column for detecting an amount of the constituent, and
iv. a heater in thermal communication with said injection chamber and said separation column for heating said injection chamber and said separation column;
a control system operatively associated with said flow monitor and said detector for calculating the energy value of the flowing gas based on the flow rate of the flowing gas and the detected amount of the constituent;
an inlet tube in fluid communication with the flowing gas for obtaining the sample;
a pressure regulator operatively associated with the sample tube for regulating the pressure of the sample;
a filter operatively associated with the pressure regulator for filtering the sample;
an outlet tube in fluid communication with said micro-miniature gas chromatograph for conveying the regulated and filtered sample gas to said micro-miniature gas chromatograph;
and
a heater in thermal communication with at least one of said inlet tube, said filter, said pressure regulator, and said outlet tube for preventing condensates from forming in the sample gas.

10 more elements

An apparatus for measuring an energy value for a flowing gas comprising:

a flow monitor for monitoring a flow rate of the flowing gas;
a pressure monitor for monitoring a pressure of the flowing gas;
a temperature monitor for monitoring a temperature of the flowing gas;
a gas sampler for obtaining a sample from the flowing gas;
a gas cartridge separately containing a carrier gas and a reference gas;
a gas conditioner for conditioning the carrier gas, the reference gas, and the sample;
a micro-miniature gas chromatograph for detecting an amount of a constituent of the sample bearing on energy content of the flowing gas comprising:
i. a micro-capillary injection chamber in selective fluid communication with an inert carrier gas and the sample for mixing the carrier gas and sample into a gas mixture,
ii. a micro-capillary separation column having a first opening in fluid communication with said chamber for receiving the gas mixture and a second opening for exhausting the constituent separated from the gas mixture,
iii. a detector in fluid communication with said second opening of said separation column for detecting an amount of the constituent, and
iv. a heater in thermal communication with said injection chamber and said separation column for heating said injection chamber and said separation column;
a control system operatively associated with said flow, temperature, and pressure monitors, said gas sampler, said gas conditioner, and said micro-miniature gas chromatograph for determining the energy value for the flowing gas based on the flow rate of the flowing gas, the temperature of the flowing gas, the pressure of the flowing gas, and the detected amount of the constituent;
and
wherein the combination of said control system, said micro-miniature gas chromatograph, and said flow meter require less than 2W of power in operation.

11 more elements

Dependencies are inferred from the claim text.