Chemistry: electrical and wave energy – Processes and products – Processes of treating materials by wave energy
Reexamination Certificate
2000-03-10
2001-12-11
Gorgos, Kathryn (Department: 1741)
Chemistry: electrical and wave energy
Processes and products
Processes of treating materials by wave energy
Reexamination Certificate
active
06328854
ABSTRACT:
TECHNICAL FIELD
This invention relates generally to the manufacture of methanol, and more particularly to a method of and apparatus for manufacturing methanol from methane.
BACKGROUND OF THE INVENTION
Methanol, the simplest of the alcohols, is a highly desirable substance which is useful as a fuel, as a solvent, and as a feedstock in the manufacture of more complex hydrocarbons. In accordance with the method of methanol manufacture that is currently practiced in the petroleum industry, methane is first converted to synthesis gas, a mixture of carbon monoxide and hydrogen. The synthesis gas is then converted over an alumina-based catalyst to methanol. The formation of synthesis gas from methane is an expensive process.
As will be apparent, methane and methanol are closely related chemically. Methane comprises a major component of natural gas and is therefore readily available. Despite the advantages inherent in producing methanol directly from methane, no commercially viable system for doing so has heretofore been developed.
SUMMARY OF THE INVENTION
The present invention comprises a method of and apparatus for manufacturing methanol from methane which overcomes the foregoing and other deficiencies which have long since characterized the prior art. In one aspect, the method involves a semipermeable partition upon which a light-activated catalyst capable of producing hydroxyl radicals from water is deposited. Water is passed over the catalyst side of the porous surface and methane at a positive pressure is present on the opposite side of the surface. The catalyst is exposed to light while water is passed over the catalyst. The light-exposed catalyst reacts with the water molecules to form hydroxyl radicals. The methane gas is forced through the semipermeable partition forming small bubbles in the flowing water. The hydroxyl radicals in the water then undergo a free-radical reaction with the methane gas in the water to form methanol.
In accordance with the broader aspects of the invention there is generated a stream of sub-micron sized methane bubbles. Due to their extremely small size, the methane bubbles have an extremely large surface area which increases reaction efficiency. Smaller pores in the semipermeable partition facilitate the formation of smaller bubbles. Additionally, high relative velocity between the water and the catalytic surface aids in shearing the bubbles off the surface while they are still small.
In accordance with one embodiment of the invention, a porous tube has an exterior coating comprising a semiconductor catalyst. The porous tube is positioned within a glass tube and water is caused to continuously flow through the annular space between the two tubes. Methane is directed into the interior of the porous tube and is maintained at a pressure high enough to cause methane to pass into the water and prevent the flow of water into the interior of the tube. As the water passes over the porous tube, methane bubbles are continually sheared off of the sintered surface. The methane bubbles thus generated are sub-micron in size and then therefore present an extremely large surface area.
Electromagnetic radiation generated from a suitable source is directed through the glass tube and engages the semiconductor catalyst to generate hydroxyl radicals in the flowing water. The hydroxyl radicals undergo a free-radical reaction with the methane forming methanol, among other free-radical reaction products. Subsequently, the methanol is separated from the reaction mixture by distillation.
In accordance with another embodiment of the invention, a porous tube surrounds a tubular lamp. The inside diameter of the tube is larger than the outside diameter of the tubular lamp thereby providing an annulus between the tube and the lamp. Methane is directed inwardly through the porous tube and is thereby formed into submicron size bubbles and sheared by high relative velocity between the inside surface of the porous tube and water flowing in the annulus between the porous tube and the lamp. A photocatalytic layer may be placed on the interior surface of the porous tube for activation by light from the lamp.
REFERENCES:
patent: 5779912 (1998-07-01), Gonzalez-Martin et al.
patent: 6156211 (2000-12-01), Gonzalez-Martin et al.
Grosso Philip
Sherman Jeffrey H.
Gorgos Kathryn
GRT, Inc.
O'Neil Michael A.
Tran Thao
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