Patent ID: 7445761

Claim:
A method of providing compressed substantially oxygen-free exhaust gas for industrial purposes comprising: (1) extracting exhaust gas from a lean burn engine consuming natural gas fuel and air, the extracted exhaust gas having oxygen therein; (2) passing said extracted exhaust gas through a cooling step in which the exhaust gas is cooled to cause at least a substantial portion of entrained water vapor therein to condense out leaving substantially water-free exhaust gas; (3) introducing said substantially water-free exhaust gas and natural gas into a combustion chamber having means of igniting combustion therein whereby these gases are combusted to produce oxygen-neutralized exhaust gas; (4) measuring for oxygen in said oxygen neutralized exhaust gas; (5) using the measurement obtained in Step (4) to regulate the ratio of natural gas to substantially water-free exhaust gas into said combustion chamber to ensure that substantially all oxygen in said substantially water-free exhaust gas is depleted as a consequence of combustion in Step (3) providing a substantially oxygen-free exhaust gas; and (6) compressing said substantially oxygen-free exhaust gas to provide compressed gas for industrial applications.