Fuel Catalyst: The Oxygenation of Diesel and Heavy Fuel Oils
A fuel catalyst is a pre-combustion device that increases the fuel economy of a combustion engine and reduces emissions. Fuel additives and fuel detergents are not fuel catalysts. A fuel catalyst is not a catalytic converter. However, a fuel catalyst performs many of the same functions as fuel additives, fuel detergents, and catalytic converters. Like additives and detergents, fuel catalysts keep an engine running clean and efficient. Like a catalytic converter, a fuel catalyst reduces emissions.
But, fuel catalysts increase the fuel economy — the “gas” mileage — of a combustion engine. Fuel additives and detergents and catalytic converters do not, at least not to a noticeable degree.
Hydrocarbon Oxygenation as a Combustion Efficiency Variable Relevant to Fuel Efficiency
Combustion inefficiency is a major factor determining the fuel efficiency of an engine. Combustion efficiency is a measure of the amount of fuel fed into an engine in relation to the amount that produces energy. All combustion engines waste some portion of the fuel fed into the engine. Portions of the fuel fed into every combustion engine simply blow out the tailpipe as emissions.
There are a variety of reasons combustion engines waste some of the hydrocarbons in fossil fuels. Several factors determine the number of hydrocarbons fed into an engine that goes unburned or that are burned incompletely. One of the primary reasons — particularly for energy-dense fossil fuels like diesel and fuel oil — is poor hydrocarbon oxygenation.
Fuel catalysts increase the oxygenation potential of fossil fuels. That is to say, fuel catalyst prime fossil fuels hydrocarbons for oxygenation. The active elements in fuel catalyst are noble metals. The noble metals in a fuel catalyst are the same used in catalytic converters to reduce post-combustion emissions. They are also the same noble metals used at crude oil refineries to in the hydrogenation-dehydrogenation stage of hydrocracking.
Which Fuels Require Oxygenation Aids
The same reason metals rust is the reason fossil fuels burn, oxidation. The oxidation of fossil fuels — ignition/burning/combustion — requires oxygen. If the hydrocarbons in fossil fuel are without exposure to oxygen, they will not oxidize. For low-density fuels, oxygenation is not an issue. Particularly for gas-state fossil fuels, ease-of-oxygenation is almost an inherent trait.
Even gasoline is thin and light enough that oxygenation is not a major issue. A vacuum driven carburetor is sufficient to agitate gasoline hydrocarbons. Simply converting liquid gasoline into a mist mixes gasoline hydrocarbons with enough oxygen for them to oxidize. Though gasoline fuel injectors produce higher combustion efficiency, injectors are not absolutely necessary.
Diesel and fuel oil, on the other hand, are extremely dense in relation to other fossil fuels. The hydrocarbons in diesel and fuel oil are large and long. Additionally, the hydrocarbons in diesel and fuel oil pack together tightly. Efficiently oxygenating heavy, dense, tightly packed hydrocarbons requires advanced diesel engine technologies.
The first step toward increasing the oxygenation potential of a heavy fossil fuel begins at the refinery.
Increasing Oxygenation Potential of Fossil Fuels During Refining
A barrel of crude oil contains different categories, classes, and sizes of hydrocarbons. Every fossil fuel has a specific hydrocarbon mix composition. Refineries separate the hydrocarbons that comprise crude oil to make different fossil fuels. Crude oil contains light, medium, and heavy hydrocarbons.
Different fossil fuels contain different mixtures of the hydrocarbons in fossil fuel. For example, diesel and fuel oils primarily consist of saturated hydrocarbons. “Petroleum-derived diesel is composed of about 75% saturated hydrocarbons (primarily paraffin including n, iso, and cycloparaffins), and 25% aromatic hydrocarbons (including naphthalenes and alkylbenzenes). The average chemical formula for common diesel fuel is C12H24, ranging approximately from C10H20 to C15H28.”
Medium weight fossil fuels from crude oil have similar chemical compositions. But as the label explains, medium weight fossil fuels contain lighter hydrocarbons than those found in diesel and fuel oil. So too do lightweight crude oil derivatives like butane and liquid petroleum gas fuels have a hydrocarbon formula. Butane and LPG have light, small hydrocarbons.
Fossil Fuel Weight and Oxygenation Correlation
Separating the fossil fuel hydrocarbons in a barrel of crude oil is as simple as raising its temperature. At different temperatures, different fossil fuel hydrocarbons vaporize. Once the vaporized, low-pressure holding tanks pull the vaporized hydrocarbons in for storage. Then, the temperature of the distillation column rises further heating the remaining crude oil. The storage process repeats and the temperature of the distillation column rise again.
Lighter hydrocarbons vaporize first, then medium weight hydrocarbons. Heavy hydrocarbons vaporize last. “Distillates” is the name of the separated hydrocarbons. But, there are hydrocarbons in crude oil that will not vaporize. The hydrocarbons that remain in a distillation column after the last cycle have the label “residuals.”
Light distillates oxygenize rapidly and without a great deal of prompting. Heavy fossil fuel hydrocarbons do not. And, residual fuels have a very poor oxygenation potential. A lack of oxygenation potential means a fossil fuel has a limited number of uses.
In order to increase the oxygenation potential of heavy and residual fuels, refineries put fossil fuels through cracking processes. Cracking is the process of breaking hydrocarbons into smaller sizes and shorter lengths. Hydrocracking is the process by which refineries resize residual fuel hydrocarbons to produce diesel. Fluid catalytic cracking is the process by which refineries resize residual fuel hydrocarbons to produce gasoline.
Hydrocracking Versus Fluid Catalytic Cracking
There are other differences between hydrocracking and fluid catalytic cracking (FCC) aside from the fact that one produces diesel and the other produces gasoline. “The primary objective of both cracking processes is to produce lighter saturated hydrocarbons with reduced molecular weights and boiling points from heavy oils. But, catalytic cracking is a carbon rejection process, hydrocracking is in a hydrogen addition process.”
Not only do hydrocracking and fluid catalytic cracking produce different fuels, but hydrocracking also removes contaminants like sulfur and nitrogen. But again, the principal purpose of both cracking processes is to produce hydrocarbons that oxygenate — and by extension, burn — more easily.
Increasing Oxygenation Potential of Fossil Fuels Prior to Combustion
Gasoline is a lighter, more volatile fuel than diesel and therefore oxygenates more easily. Still, as a liquid the oxygenation potential of gasoline has limits. Therefore, the modern fuel injection systems of gasoline engines convert liquid gasoline into a light spray. By converting gasoline into micro-drops, a fuel injection system oxygenates the gasoline.
Diesel, on the other hand, is a far heavier and denser fuel than gasoline. Even the high-pressure injection systems on today’s diesel engines fail to prime diesel for complete oxygenation. Recently, an effort was made to produce ultra-high-pressure injection systems. In fact, the U.S. Army was one of the factions most interested in creating ultra-high-pressure injection systems.
“The Army uses intensified fuel injection systems on a number of their diesel-powered vehicles. These systems are currently limited to injection pressures of about 20,000 psi. In an effort to increase thermal efficiency (fuel economy), raise power output and operate on a variety of heavy hydrocarbon fuels, the army desires to develop an ultra-high pressure (>40,000 psi)intensified fuel injection system.”
However, the success of these systems was limited. For one, there was no evidence that ultra-high-pressure systems actually increase fuel efficiency or power ratings. And two, ultra-high-pressure injection systems are both difficult to maintain and often create engine wear and damage not associated with lower pressure injection systems.
Increasing Oxygenation with a Fuel Catalyst
Another means of increasing the oxygenation potential of diesel fuel is to make it a homogeneous mixture. Even after the refining process, diesel is a heterogeneous mixture of hydrocarbons. Rather than hydrocarbons being uniformly distributed throughout diesel, the hydrocarbons clump together into clusters.
The clusterization of hydrocarbons is a product of the fact that hydrocarbons have a natural charge. The charges of hydrocarbons atoms bring them together to create clusters. “Most fuels for internal combustion engine are liquid, fuels do not combust until they are vaporized and mixed with air. Most emission motor vehicle consists of unburned hydrocarbons, carbon monoxide and oxides of nitrogen. Generally, fuel for an internal combustion engine is a compound of molecules. Each molecule consists of a number of atoms made up of a number of nucleus and electrons, which orbit their nucleus. Magnetic movements already exist in their molecules and they therefore already have positive and negative electrical charges.”
The problem with hydrocarbon clusters is that the hydrocarbon molecules on the inside of a cluster have no exposed surface area. Without exposed surface area, hydrocarbons can not oxygenate. If a hydrocarbon is not oxygenized, it will not oxidize. That is to say, without oxygen, a hydrocarbon will not ignite/combust/burn.
How the Rentar Works
The Rentar Fuel Catalyst contains noble metals similar to those found in a catalytic converter or a hydrocracking plant. The noble metals in the Rentar neutralize the charge binding hydrocarbon fuel clusters together. Once the charge disappears, hydrocarbon clusters drift apart into individual hydrocarbon molecules. So essentially, the Rentar changes diesel fuel from a heterogeneous mixture into a homogeneous mixture.
The oxygenation of diesel fuel makes engines run more efficiently. Hence, the Rentar makes engines more fuel efficient. In fact, the Rentar is proven to improve fuel efficiency between 3 and 8 percent on over-the-road vehicles. With the Rentar Fuel Catalyst, off-the-road vehicles and machines get even better fuel savings.