This invention relates to a novel composition. In one aspect, this invention relates to processes to make said composition. In still another aspect, this invention relates to uses of said composition.
Light hydrocarbons are commercially significant as fuels, and as chemical intermediates in numerous industrial and domestic applications. Many gases which are potential sources of light hydrocarbons also contain carbon dioxide. For instance, subterranean deposits of natural gas frequently contain carbon dioxide along with light hydrocarbons such as methane, ethane, propane, butane and the like. If the carbon dioxide content of the natural gas is too high, then the gas will have little or no commercial value as fuel. The use of the gas will determine whether or not a given concentration of carbon dioxide is considered as high. For instance, where the gas is used as a town gas for home heating, the fuel value which represents the thermal energy per unit volume of gas must meet specific standards. If the gas contains too much carbon dioxide, then the energy content of the gas will be inadequate for the intended use. In industrial uses such as boilers and furnaces, a fuel value that is less than the fuel value of a town gas may be acceptable. However, gases with only twenty to thirty volume percent methane or the like based on total volume of gas have an extremely poor fuel value and are frequently not commercially acceptable for any use as a fuel.
Gases that have a relatively high carbon dioxide content and a relatively low content of light hydrocarbon generally have not been commercially utilized as fuels. The costs of separating the carbon dioxide from the light hydrocarbon are often prohibitive. Furthermore, major deposits of carbon dioxide-rich natural gas have been found offshore and in other remote locations. For example, it has been reported that large natural gas reserves in certain Siberian fields contain about 15 volume percent carbon dioxide and about 85 volume percent methane. Also, large deposits of natural gas found in the South China Sea are said to contain only about twenty volume percent methane and contain about eighty volume percent other constituents, of which carbon dioxide is reported to be the most abundant.
The transportation of a gas containing a light hydrocarbon from a remote source to a market poses technical and economical problems. For instance, there are presently three major modes for transporting gas containing a light hydrocarbon. These are gas pipelines, condensation of the gas to a low temperature liquid and transporting the refrigerated liquid by pipeline or vessel, and partial oxidation of the light hydrocarbon in the gas with air to produce methanol which can be transported by pipeline or vessel in liquid form without refrigeration. All of these modes are in commercial use, but are useful only under certain circumstances or have serious problems associated with their use.
Significant problems are incurred with transportation of light hydrocarbons by condensation and transportation as liquids. Liquid methane, for instance, has a low density and an extremely low boiling point. Boiling at -161.5.degree. C. at atmospheric pressure, liquid methane is generally transported in heavily insulated tankers, the cargo capacities of which are small compared to the size and cost. Liquid methane has a density of only about 0.415 g. cm.sup.-3 compared to a density of 0.8 for a medium light crude oil. Thus a barrel of cargo capacity will transport only about 146 lbs of liquid methane compared to about 300 lbs of crude oil.
Likewise the conversion of light hydrocarbons in methanol for transportation faces serious problems, even though methanol is a liquid which can be transported in conventional tankers and pipelines. For example, the current conversion of methane to methanol through controlled oxidation with air has several disadvantages. The partial oxidation reaction is exothermic and results in a loss of about 18.4% of the potential thermal energy of the methane. This loss represents about 1.08 million B.T.U. per equivalent barrel of crude oil, assuming that approximately 6,000 cu. ft. of methane is equivalent in potential energy to a barrel of crude oil. Also, methanol has a relatively low density, 0.7865 at 25.degree. C. Thus, more tanker volume is required to transport methanol as cargo as compared to denser liquids. Methanol also has a low heating value, 2.7 million B.T.U. per barrel versus 6.0 for crude oil.
In addition to problems associated with transporting, a gas presents storage problems also. These problems are incurred at the well head production source and at the location where the gas is used. Vast storage tanks adequate to accommodate large volumes of gas are often not available.
The transportation of solids or very viscous materials also presents technical and economic problems. Like natural gases, difficult to handle solid fuels such as coal, wood chips, and plant matter often have a source that is a great distance from a market. Some solid fuels are bulky and do not lend themselves well to some conventional modes of transportation unless they are combined with a liquid to form a slurry. Viscous bituminous mixtures such as asphaltic crudes, residual fuel oils, shale oils and tar sand extracts are akin to solid fuels in that they cannot easily be transported, since they cannot be pumped or otherwise moved, without heating and/or admixing with a dispersing agent or diluent. They can thus be considered equivalent to a solid fuel.
Many different slurry agents have been used with solid or viscous fuels. Coal, for instance, has been combined with water and with methanol. Slurrying coal with water presents numerous problems. The supply of water at many sources of coal is limited. Some states have passed laws forbidding the use of water to slurry coal for pipeline transport. There are a great many practical reasons for not pumping water along with coal from an area that has a limited water supply. Also, coal suspended in water easily separates. Thus upon any flow interruption, coal can settle out and block lines, valves, pumps, etc. A more stable slurry is needed. Coal that is too wet cannot be burned directly as a fuel. A certain amount of the water slurry agent must be separated from the coal and be disposed of. The disposal of a water slurry agent for coal can cause pollution problems. Water can pick up various contaminants such as iron, sulfur, or selenium from the coal. Solid fuels have also been combined with methanol. Methanol when used alone as a slurry agent can be very expensive, especially when the source of the methanol is a great distance from the source of the solid fuel.
The need for solutions to these problems increases with the demand for alternate sources of energy.