Field of the Invention

The invention relates to a process for the rapid transesterification of a fat using alcohol and a transesterification catalyst, as well as to a semisolid grease.

Background

It is widely know that the world cannot continue to use hydrocarbon based products going forward. Many reason exist for this;

1. Insecurity of supply for individual countries.

2. Environmental pollution.

3. Dwindling reserves of fossil hydrocarbons.

4. Health risks.

The world is changing, and what affects one country affects another. As recent events have shown, a commodity like oil, can have a great impact on the financial health of individual countries. Many millions of litres of hydrocarbon oil are being used all over the world. The demand for environmentally acceptable products is growing rapidly. There is increased concern about the effect of petroleum-based oils on the environment. One potential alternative is the use of "environmentally compatible" or "enviro-friendly" oils that are produced from vegetables. To achieve this classification, an oil must be nontoxic and must biodegrade rapidly if spilled. For instance, such oils are used as industrial lubricants or even automobile fuels after chemical processing.

Rapeseed-based (usually called canola) oil is currently the most common environmentally compatible chain-and-bar lubricant. However, in a time of concern for the world food supply, rapeseed oil used to lubricate chains is sadly wasteful of a highly valuable food. The proponents of rapeseed oil maintain that it is one of the most heart-healthy oils, and it has been reported to reduce cholesterol levels, lower serum triglyceride levels, and keep platelets from sticking together. When used as a chainsaw lubricant however, vast amounts of this food source is being discarded in our forests. A typical chainsaw uses 3 litres per day.

In Germany alone, 10 million litres of bar and chain oil are used annually. Thankfully, Germany at least has compulsory laws which make it illegal to use hydrocarbon lubricating oils for machinery like chainsaws, which improves the health of harvesters involved in forestry cultivation, as well as the health of our forests. However, many other countries allow the use of polluting hydrocarbon oil, and consequently billions of litres of this oil are sprayed directly into the environment. From a purely mechanical perspective, hydrocarbon oils are typically preferred as they are stickier and have better lubricating properties.

Different types of biofuel have been contemplated as replacements for hydrocarbon fuels, in search for alternatives that are non-toxic and biodegradable and thus environmentally compatible. For instance, biodiesel can be produced from waste vegetable oil, after it has already been used for food preparation. The biodiesel process involves transesterification of a fat with alcohol in presence of a catalyst, resulting in biodiesel and the byproduct glycerol. Though thousands of consumer products contain glycerol as an ingredient, the crude glycerol produced in a biodiesel process is typically regarded as waste. It is not feasible to refine raw glycerol produced by biodiesel facilities to a sufficient purity for consumer products. Glycerol is very difficult to burn, and only minor quantities of it can be used in anaerobic digesters etc. Many biofuel plants must pay to dispose of it. The average industrial biofuel facility will produce 70,000 litres of glycerol per week. This waste can be from 17% to 40% of the oil or fat being converted, depending on the quality of that oil.

To avoid producing too much waste glycerol, biofuel manufacturers naturally attempt to optimize the biofuel yield of their processes. For instance, it is common to minimize the amount of transesterification catalyst used, as higher amounts lead to a greater glycerol fraction and a smaller biofuel fraction. This is usually accomplished by titrating the amount of catalyst needed. There are hundreds of different types of organic fats, and the reactant is often contaminated, for example when using waste vegetable oil that has first been used in cooking. No two batches of oil are the same. For instance, the vegetable oil could be contaminated by animal fats from meat, or fish, or food particles.

This means that each batch must be tested to see what contaminants its contains, then a blend of suitable chemicals is made, and added in several steps to the oil or fat. Most biofuel facilities require 27 hours to convert a batch of oil and fat. The process can be made quicker, by the addition of extra chemicals, but this is wasteful, and expensive as they must then be removed. When fully reacted, the result is a mixture of glycerol and biodiesel, which can take weeks to fully separate. Many facilities use expensive spinning devices to facilitate separation, or spray water on the mixture to wash the glycerol out of the bio diesel. However this adds to problems, as the fuel is then oxidized, and becomes unstable, unless expensive antioxidants are added. Current bio diesel processes are also unreliable. Both large and small scale producers will regularly report failed batches. This can be due to a multitude of reasons, such as the age of the oil, unexpected contaminants, inaccurate measuring equipment, human error etc.

To summarize, it has been hard to replace hydrocarbon oils with good alternatives. In the field of lubricants, the industry has turned to vegetable oils which have poorer mechanical properties and waste a valuable food resource. This is particularly troubling considering that the modern intensive food industry is one of the main consumers of hydrocarbon fuels. As for replacing the fuels, current biodiesel processes must struggle to achieve cost efficiency when producing a substantial amount of glycerol waste. Attempting to optimize biodiesel yields have led to slow, unreliable or overly complicated processes that do little to improve the cost efficiency.

Summary of the Invention Most surprisingly, the applicant accidentally found that using an excess amount of catalyst permits a fat transesterification process, which produces a grease with amazing properties, that can be used immediately in industrial applications, rather than waste glycerol. The new process makes no use of unnecessary chemicals and can be used for a wide range of reactants. The process is extremely quick, requiring only minutes rather than weeks to achieve complete separation between the biofuel fraction and the glycerol grease fraction. The new process is simple, inexpensive and reliable. Furthermore, the new glycerol grease was found to have exceptional lubricating qualities for use with machinery with rapidly rotating parts, such as chainsaws. Since it is a grease rather than an oil, it can adhere to rotating parts much better than current fluid lubricants. However, since it also contains a high concentration of emulsifiers, the grease mixes readily with various volatile solvents, permitting easy application of the diluted grease. Furthermore the new grease is completely bio degradable, as it was once part of an organic product. Thus, in one operation, it is now possible to produce a new biodegradable lubricant, and a biodiesel fuel.

Therefore there is no waste. Thus, in a first aspect, the invention relates to a process for the rapid

transesterification of a fat using alcohol and a transesterification catalyst, wherein an excess amount of catalyst is used to cause formation of a semisolid grease.

According to this aspect of the invention, it is preferable that the amount of catalyst is at least 50%, more preferably 100%, most preferably 200% or more in excess of the amount needed to carry out the rapid transesterification. It is even possible to use a sufficient amount of catalyst to convert all or substantially all of the reactants into a grease. Preferably, the alcohol is methanol and the catalyst is KOH. In such a case, it is preferred that the KOH is dissolved in a sufficient amount of methanol, whereafter the dissolved KOH in methanol is added to the fat, so that the total amount of KOH used is at least 1.5%, more preferably 2.0%, most preferably 3% or more by weight of the fat. It is also contemplated that the dissolved KOH in methanol could be added in two or more steps. Preferably, the fat is vegetable oil.

In a second aspect, the invention relates to a semisolid grease, obtainable through the process according to the first aspect of the invention. Several uses are contemplated for this grease, for instance its application as an emulsifier, herbicide, lubricant or lubricant additive.

In a third aspect, the invention relates to a semisolid grease, comprising glycerol, glycerid emulsifiers and fat. According to this aspect of the invention, the grease may also comprise an amount of volatile solvents to temporarily reduce the viscosity of the grease.

Detailed Description of the Invention

A wide array of greases are known. For instance, WO03018729 (to Abcon APS et al.) describes a non-toxic biodegradable grease.

Biodiesel production is common in many parts of the world, both in large scale and for personal use in more improvised reactors. A seminal work in the field, especially for the general public, was presented 2003 by Tickell, entitled "From the Fryer to the Fuel Tank" (ISBN 0-9707227-0-2, available on-line). Tickell teaches titration in order to find the exact amount of base catalyst needed, first describing the use of NaOH as a catalyst. Typically, the amount of NaOH is about .35% of the volume of new vegetable oil. KOH is also described, using an identical titration technique. Typically, the amount of KOH used is about .9% of the volume of new vegetable oil. Tickell describes using methanol or ethanol as the reactant alcohol. Furthermore, Tickell describes that the waste glycerol could be discarded on the ground, composted or used as a degreasing soap.

Several patents have been granted in the field of biodiesel production. For instance, WO2009095668 (to Quicksilver LTD) describes the transesterification of vegetable oils. Also, US5713965 (to the US Army) describes the production of biodiesel, lubricants and fuel and lubricant additives.

Definitions

As used herein, the term "fat" means triesters of glycerol and fatty acids. The fat could contain various such triesters, with fatty acids of various chain lengths. The fatty acids could be saturated, unsaturated or polyunsaturated. For instance, "fat" could signify vegetable oil or animal fat. The fat need not be a pure substance, but could contain various contaminants, or even comprise a mixture of fats. As used herein, the term "alcohol" refers to any alcohol normally used for the transestenfication of fats, such as ethanol or methanol. A person skilled in the art will appreciate which alcohols are suitable reactants for a transestenfication reaction. Preferably, the alcohol is methanol.

As used herein, the term "transestenfication catalyst" refers to any catalyst used in the transestenfication of fats, or a combination thereof. Typical examples include NaOH and KOH. A skilled person will realize that the choice of catalyst will affect the chemical composition of the end product, as well as its properties, such as viscosity. It is contemplated that a skilled person may combine different catalysts to achieve certain product properties.

As used herein, the term "excess amount" as in "excess amount of catalyst" means an amount in excess of the minimum amount of catalyst needed to carry out the transestenfication reaction in a timely fashion. Known rapid transestenfication processes concerned with the production of biodiesel attempt to minimize the amount of catalyst used in order to improve yields. As a person skilled in the art will appreciate, the exact amount of catalyst needed varies depending on the reactant material, and is usually determined on a case-by-case basis through titration. At any rate, the transestenfication process according to the invention requires a significantly greater amount of catalyst to be used in order to achieve the invention, i.e. a semisolid grease. Typically, the amount of catalyst is at least 50%, more preferably 100%, most preferably 200% or more in excess of the amount needed to carry out the rapid transestenfication. A skilled person can easily determine if the amount of catalyst used was sufficient to achieve the invention, by examining whether a grease was formed or not (after allowing residual solvents to evaporate etc.)

As used herein, the term "grease" refers to a semisolid substance, or such a substance dissolved in volatile solvents, making it temporarily more liquid. The grease is an emulsion consisting of various known and unknown compounds, for instance fats, emulsifiers, soaps, alcohols etc. Once any volatile solvents have evaporated sufficiently, the grease will not be runny, but adhere to most surfaces.

As used herein, the term "sufficient amount" as in "sufficient amount of methanol" means an amount sufficient to carry out a transestenfication reaction, unless otherwise noted. It is common to add alcohol in excess rather than in stochiometric amounts, so as to drive the reaction to completion more readily. A skilled person can determine how much of a reactant alcohol such as methanol is needed to carry out the reaction. Typically, an amount of methanol of about 20% by volume of the reactant fat is used. In the invention, it is preferred not to use an overabundance of methanol, as a greater time or effort is then required to let the methanol evaporate from the grease according to the invention.

Properties of the Grease According to the Invention

Chemical analysis of a grease sample produced according to the invention has revealed that the grease, once water, methanol and other volatile solvents evaporate, contains about 20-40% glycerol, about 20-30% mono- and diglycerides and about 20-30% other organic compounds including methylesters, fats and soaps. The free and bonded fatty acids in the sample comprised about 10-20% stearic and palmitic acid, which are solid at room temperature. Without being bound by any particular theory, it is assumed that the mono- and diglycerides act as emulsifiers, permitting the stable mixing of glycerol and non-polar organic substances. The fatty acid composition in the glycerides and other organic compounds are believed to increase the viscosity of the emulsion beyond that of crude glycerol, thus achieving a grease. As glycerol, glycerides, methylesters, fats and soaps all have lubricating properties, it is believed that the excellent properties of the grease according to the invention is a combination effect from several of its constituents. Nevertheless, a defining feature of the inventive grease is the high content of glycerol in combination with a high content of glycerid emulsifiers, making the glycerol miscible with non- polar lubricating substances such as fat.

The chemical composition of the grease not only makes it suitable as a lubricant, but for instance also as an emulsifier. It could also serve in this capacity as a lubricant or fuel additive. The high content of emulsifiers makes the grease readily miscible with both polar and non-polar substances, which also makes it an excellent detergent. As it is non-toxic and biodegradable, it is even suitable for use as a consumer soap, or degreaser, especially under industrial conditions. These properties also make it suitable for use as a herbicide, as a thin, greasy film could be applied to a plant, for example by simply diluting the grease with water and spraying it onto the plant. Other potential uses include all known uses of lubricants and emulsifiers, in particular where a non-toxic and/or biodegradable product is preferred. As a lubricant, the inventive grease has many advantages. As it is a grease rather than a liquid oil, it adheres more readily to machinery. It prevents dirt from entering intricate parts of the machinery as the grease fills up small spaces. Oil is very poor in this respect. The inventive grease has a very high density, the highest in fact of all chain oils to date. For instance, compared to vegetable oil when used as a chainsaw lubricant, this means 40% more heat reduction, keeping bar and chain cool under high pressure, and high rpm's.

The high content of emulsifiers means that the lubricant washes easily from clothing and machinery. It also cleans the machinery. For instance, should a chainsaw contact soil when lubricated with the inventive grease, placing the chain under a water hose simply washes away all soil, leaving the bar and chain immaculately clean. In other words, it does not become an oily grinding paste. This is contrary to many other water miscible products, where machinery tends to be coated with dust, and tend to gather dust, looking dirty most of the time. Another example of the usefulness of the emulsifiers in this application, is its potential to dissolve pitch or sap, for example from pine trees. This pitch or sap tends to shorten the life of a chainsaw.

Furthermore, the inventive grease is considered an ECL (environmentally considerate lubricant) as it is composed of natural substances, and as it is water miscible, and breaks down in the soil readily. Therefore the operator may for instance use it near bodies of water without environmental problems. Mineral oils cannot be used near water as the spray can drift ten feet or more, especially if the operator is high in the tree line. The ECL grease according to the invention will also not spray into a fine mist and cause illness for the operator. It is non-carcinogenic, virtually inert, and completely safe.

The grease has unlimited shelf life. Vegetable oil based lubricants must contain antioxidants etc. to prolong life. However the grease according to the invention is stable. It will not gum, oxidize, carbonize, polymerize, gel or putrefy due to bacteria, in any way. When used, the inventive grease will not become thicker, but remain a light grease under all circumstances for lubrication, reducing drag, heat- very high pressure and rpm resistance. Even years later, the inventive grease will not become hard, or thicker, or deteriorate. Nor will the grease according to the invention 'coke' and leave material residues if the blade gets hot. Vegetable oil leaves a 'coke' (similar to a frying fan) on the chain, building up over time. The new grease cannot do this, as the boiling point is over 300 degrees centigrade.

Producing the Grease According to the Invention

In the process of the invention, a semisolid grease is produced through a process for the rapid transesterification of a fat using alcohol and a transesterification catalyst. This is accomplished through using an excess amount of catalyst compared to what is normally needed to carry out the transesterification, for instance when attempting to produce methylesters as a fuel. Typically, the amount of catalyst needed is at least 50%, more preferably 100%, most preferably 200% or more in excess of the amount needed to carry out the rapid transesterification. If the alcohol is methanol, the catalyst is KOH and the fat is high quality vegetable oil with a low content of FFA's (free fatty acids), this usually translates to a total amount of KOH used of at least 1.5%, more preferably 2.0%, most preferably 3% or more by weight of the oil. Though the exact amount of catalyst needed depends on the process conditions and reactants used, a skilled person can easily determine if the invention has been achieved by examining whether a grease was formed in the glycerol fraction or not. Typical concentrations of catalyst produce a glycerol fraction that remains liquid after solvents evaporate, and thus does not form into a grease.

The alcohol used in the invention is typically a C1-C5 alcohol, preferably methanol or ethanol. The alcohol is typically added in excess. When methanol is used, a typical amount is 20% by volume of the reactant fat. If a more diluted grease is desired, for example to facilitate application of the grease onto a surface, a greater amount of alcohol could be used. If a less diluted grease is desired, the alcohol could be used in stoichiometric or near-stoichiometric amounts. The fat used in the invention may be a low-grade lipid material derived from animal fats and vegetable oils, including recycled fats and oils and waste grease. Such low-grade lipid materials are very complex and are typically difficult to economically process using the current state of the art because of their high free fatty acid levels (ranging from a few percent to 50 percent, and higher). The transesterification catalyst is preferably a base catalyst. Suitable base catalysts include such alkali catalysts as potassium hydroxide (KOH) and sodium hydroxide (NaOH). Alternatively, an alkoxide, such as potassium methylate, may be added to the transesterification reactor to facilitate the base catalysis. As such, the rapid conversion of glycerides to alkyl esters may occur in the presence of caustic alkoxide, such as caustic methoxide catalysts. The transesterification reaction typically occurs at a temperature in the range of about 25° C. to about 65° C, preferably from about 55° C. to about 65° C, and at a pressure of about 14.5 psia to about 3,625 psia. Regardless of pressure, it is preferred that the temperature is above the melting point of the reactant fat, but below the boiling point of the reactant alcohol. Preferably, multiple alcohol or catalyst additions are made to the transesterification reactor. The invention does not need to use acids to first esterify the feedstock, as the production of a semisolid grease is the objective of the invention, rather than maximizing the yield of methylesters.

A base catalyst for example KOH can be difficult to dissolve in the alcohol such as methanol. Many use electric paddles to mix the solution, while adding the base to the alcohol. However, the base will stick to the bottom of the reactor, in a hard glassy layer. This complicates things, as it must now all be dissolved, or the mixture will not be potent enough. To cure this, it is preferable to keep the base catalyst suspended in the alcohol solution. This way, it cannot adhere to the floor of the reactor. One method is to use pumps to mix the solution. However, this would necessitate the use of filters to prevent the alkali base entering the pump. This is because the base is normally solid before it is dissolved, and can block a pump with solid base catalyst. A solution is to use a pump to draw alcohol from the top of the reactor vessel, and pump it up, similar to a fountain, inside the reactor vessel, but the reactor vessel is full.

Therefore an upward current is formed. This constantly blows base up, away from the floor of the vessel, into the body of the reactor. It is helpful to have a reactor vessel which is cone shaped for this purpose. The base is then added to the vessel, but none of the base enters the pump, as it is sucking from the top of the reactor vessel.

The chemical reaction between the base catalyst and the alcohol will cause heat. Therefore it is advisable to use a steel container, preferably stainless steel. Also, due to heat, the volume of alcohol is likely to increase, so it is preferable if the reactor has enough room to accommodate about 25% extra volume. Adding the base in the concentrations used in the invention, will lead to significant heat as explained above. This may cause violent boiling of the alcohol, which is very dangerous. Thus, it is preferable to add the base catalyst over time while allowing the alcohol to cool between additions.

While adding the solution of catalyst and alcohol to the feedstock, it is preferable to have the fat circulating in the reactor vessel with sufficient force that it is visibly moving, and swirling in the reactor vessel. Using a strong centrifugal pump [3kw pump per 1000 litre] is an excellent, versatile, and reliable solution. Also, if a nozzle is used where the fat enters the reactor vessel, this will concentrate, and speed up the flow, creating small vortices, and encouraging the total volume to be in constant motion. One can also have an adjustable obstruction in the outflow of the hot oil. By adjusting this obstruction, one can obtain cavitation without expensive equipment. One may know if cavitation is occurring by a type of wailing sound, or hammering sound. Using a stethoscope placed at the obstruction, one can hear cavitation as a type of rushing sound. By adjusting the flow, using a tap or some such, one can attempt to make this noise louder, and this will be the optimum point for cavitation to occur. These steps help drive the transesterification process.

If so desired, the resulting grease can be used to purify the biodiesel fraction after settling. Mixing the two fractions will produce an unstable emulsion, where the glycerol grease soon separates out again. The tremendous emulsifiers in the grease will clean the biodiesel of many impurities. When the grease reforms into globules, it tends to attract at a site of nucleation, usually a particle, and due to the growing weight, brings any particles to the floor of the reactor vessel. The invention, having been fully disclosed by the above description, will now be further illustrated by means of the following non-limiting examples. They should not be construed as limiting the scope of the invention, as determined by the claims. Examples

Example 1: Transesterification to Produce Biodegradable Grease and

Methylesters According to the Invention 6 grams of KOH was dissolved in 40 grams of methanol, at ambient temperature, using a pyrex glass beaker. A magnetic stirrer was used to dissolve the KOH, and the beaker was covered to prevent loss of methanol, as it heated due to chemical reaction. 200 grams of new sunflower oil with a FFA content of 0.4% was preheated to 63 degrees centigrade in a separate beaker, and a magnetic stirrer was used to agitate the oil at 230 rpm. The KOH in methanol was added to the oil and the mixture was stirred for 20 minutes. After settling for an additional 20 minutes, two fractions had formed.

The bottom glycerol grease fraction was about 33% of the total product volume, whereas the yield of methylesters was about 66%. A sample was extracted using a pipette and expelled onto a petri dish. The brown, translucent, thick liquid sample was observed to have a consistency comparable to automobile engine oil. Using a wooden spatula, the brown liquid was spread on the petri dish, and the petri dish placed in an oven at 67 degrees centigrade, to evaporate any solvents from the sample. After 4 hours, the dish was removed from the oven, and left to cool. The sample had turned into a light, translucent grease. When tapped with one's finger, the grease would form sharp 'peaks', which would remain standing, similar to margarine. Comparative Example 1: Transesterification to Produce Biodiesel and Waste Glycerol

2 grams of KOH was dissolved in 40 grams of methanol, at ambient temperature, using a pyrex glass beaker. A magnetic stirrer was used to dissolve the KOH, and the beaker was covered to prevent loss of methanol, as it heated due to chemical reaction. 200 grams of new sunflower oil with a FFA content of 0.4% was preheated to 63 degrees centigrade in a separate beaker, and a magnetic stirrer was used to agitate the oil at 230 rpm. The KOH in methanol was added to the oil and the mixture was stirred for 20 minutes. After settling for an additional 20 minutes, two fractions had formed.

The bottom glycerol waste fraction was about 10% of the total product volume, whereas the yield of methylesters was about 90%. A sample was extracted using a pipette and expelled onto a petri dish. The brown, translucent, liquid sample was observed to have a consistency comparable to cooking oil. Using a wooden spatula, the brown liquid was spread on the petri dish, and the petri dish placed in an oven at 67 degrees centigrade, to evaporate any solvents from the sample. After 4 hours, the dish was removed from the oven, and left to cool. The sample had not turned into a grease, but remained an oil like substance. The glycerol did not have the slightest tackiness to it.

Example 2: Using the Inventive Grease as a Chainsaw Lubricant A grease sample was prepared according to the invention. A ratio of 3% KOH to used oil, and 18% volume of methanol was used. The resulting glycerol grease fraction was smooth and similar to light engine oil in viscosity. This was placed in the chain oiler of a chainsaw. The chainsaw was a Stihl 090 with a 65 centimeter bar - one of the biggest chainsaws in the world, and a very powerful professional chainsaw.

The empty chain oiling chamber was filled with 500ml of the new grease invention. When the chainsaw was started, and running, the first observation was the lack of spray coming from the end of the bar. This is most unusual, as a spray of oil is normal with traditional vegetable oil lubricants, resulting in a wasteful loss of lubricant. Instead, only a few small droplets came from the bar and chain.

The chainsaw was used to cut beech tree, which was chosen due to its difficulty to cut. This is due to the wood forming a fine pulp, and removing oil, and getting onto the intricate parts of the cutting chain. After a full hour of cutting this wood, grease was surprisingly found in amongst all the links of the chain, and between the plates of the links, and the hinges of the links. Also, grease was found on all the chain, including the underneath part of the bar. This is most unusual, as normal chain oil is removed, and flung away long before it reaches the bottom of the bar. The bottom of the bar is normally dry.

For second trials, a smaller Stihl chainsaw was used, having a new chain and bar. The new grease performed just as well in the smaller chainsaw, and surprisingly, at the end of the work day after seven hours of cutting, the chain did not need adjusting. This is very unusual, and indicated the grease was performing in practice, as it was in theory. The chain was not wearing nearly as much, because of the lubrication it was getting. During testing it was also noted that the chain did not get very hot, and remained sharper. This is due in fact to the chain not wearing as much. When a chain wears, the angle of the blades changes a little, so that the operator must then apply more pressure to achieve the same speed of cutting. But as the chain was fully lubricated, the chain remained sharp. The pump of the chainsaw was then adjusted to output 50% less oil to the chain. This was thought to be too low, based on experiences with traditional lubricants. However, after one hour of cutting, the chainsaw unexpectedly remained lubricated, and working properly.