Reformed natural gas for powering an internal combustion engine

A method of operating an engine comprising the steps of:

• (a) providing an engine;
• (b) providing a source of gaseous fuel for powering said engine;
• (c) providing a reactor in fluid communication with said engine;
• (d) recycling a portion of said exhaust gas from said engine to said reactor;
• (e) adding gaseous fuel to said reactor in a ratio range of 0.2 to 0.35 gaseous fuel to exhaust gas;
• (f) steam reforming said gaseous fuel at an oxygen level lower than the lower flammability limit of the gaseous fuel and at a temperature in the range of 450° to 800° C. using said exhaust gas as a source of heat and water to reform at least 10% of said gaseous fuel to form a gaseous mixture comprised of hydrogen and carbon monoxide;
• (g) combining said gaseous mixture with air to provide a combination mixture having a ratio range of 0.2 to 1 gaseous mixture to air and an excess oxygen level of between about 0.5 and 4% by volume in the exhaust gas;
• and
• (h) combusting said combination mixture in said engine.

In an improved process for operating an engine to produce an exhaust gas having near-zero NOx, wherein the engine is fueled by natural gas, the improved process comprising:

• (a) providing a reactor in fluid communication with said natural gas and exhaust gas from said engine;
• (b) recycling a first portion of the exhaust gas from said engine to said reactor;
• (c) adding natural gas to said reactor;
• (d) steam reforming said natural gas in said reactor at an oxygen level lower than the lower flammability limit of the natural gas using said first portion of exhaust gas as a source of heat and water to form a gas mixture comprised of methane, hydrogen and carbon monoxide;
• (e) combining said gas mixture from said reactor with air to provide a combination mixture;
• and
• (f) combusting said combination mixture in a combustion zone in said engine to produce the first portion of exhaust gas and a second portion of exhaust gas, wherein the first portion of exhaust gas contains up to about 4% oxygen by volume and the second portion of exhaust gas has near-zero NOx.

A method of operating an internal combustion engine comprising the steps of:

• (a) providing an internal combustion engine;
• (b) providing a source of fuel gas for powering said engine wherein the fuel gas is selected from the group consisting of natural gas, propane and combinations thereof;
• (c) recycling a first exhaust gas stream from said internal combustion engine to a steam reforming zone wherein said first exhaust gas stream is mixed with said fuel gas;
• (d) catalytically steam reforming said fuel gas in said steam reforming zone to form a diluted gaseous mixture containing hydrogen, carbon monoxide and an unreacted portion of the first exhaust gas stream;
• (e) combining said diluted gaseous mixture exiting said steam reforming zone with air to provide a combination mixture;
• and
• (f) combusting said combination mixture in a combustion zone within said internal combustion engine to produce the first exhaust gas stream and a second exhaust gas stream, wherein the first exhaust gas stream contains up to about 4% oxygen by volume and the second exhaust gas stream contains near-zero NOx.

A method of operating an engine comprising the steps of:

• (a) providing an engine;
• (b) providing a source of gaseous fuel for powering the engine;
• (c) providing a reactor in fluid communication with the engine;
• (d) recycling a first portion of an exhaust gas from the engine to the reactor;
• (e) adding gaseous fuel to the reactor;
• (f) steam reforming the gaseous fuel in the reactor at an oxygen level lower than the lower flammability limit of the gaseous fuel using the first portion of the exhaust gas as a source of heat and water to form a gas mixture comprised of methane, hydrogen and carbon monoxide;
• (g) combining the gas mixture from the reactor with air to provide a combination mixture;
• (h) combusting the combination mixture in a combustion zone in the engine to produce the first portion of exhaust gas and a second portion of exhaust gas, the second portion of exhaust gas having near-zero NOx and excess oxygen;
• and
• (i) reacting carbon monoxide from the second portion of the exhaust gas with the excess oxygen in the second portion of exhaust gas to form carbon dioxide, thereby producing a treated exhaust gas having near-zero carbon monoxide.