WO2016166499A1

WO2016166499A1 - A lubricant

Info

Publication number: WO2016166499A1
Application number: PCT/GB2016/000076
Authority: WO
Inventors: Patrick Anthony DOONAN
Original assignee: 3D Eco Oil Limited
Priority date: 2015-04-13
Filing date: 2016-04-08
Publication date: 2016-10-20
Also published as: EP3283604A1; GB201506238D0

Abstract

A biodegradable lubricating oil for use with mechanised equipment such as chain driven forestry and agricultural equipment in which the lubricating oil is formed from the crude glycerol by-product of biodiesel production distilled to remove excess methanol from the glycerol by-product.

Description

A Lubricant

Introduction This invention relates to a lubricant and more particularly to an ecologically friendly biodegradable lubricating oil suitable for use with mechanised equipment such as chain driven forestry and agricultural equipment.

Background of the Invention

Lubricants such as lubricating oils are widely used to lubricate moving mechanical parts such as the chains in chainsaws, balers and the like. In general, lubricating oils are formed from mineral oils which suffer from a number of disadvantages. For example, mineral oils are generally produced from petroleum making them expensive to produce and non-environmentally friendly to manufacture, in addition, mineral oils are not biodegradable further adding to their non-environmentally friendly nature - this is particularly undesirable where the lubricating oils are being used in otherwise environmentally friendly activities such as sustainable forestry management.

Summary of the Invention

According to the invention there is provided a lubricant comprising glycerol wherein the glycerol is a by-product of bio-diesel production. Preferably, the lubricant comprises a lubricant oil for mechanised equipment.

Suitably, the lubricant oil comprises from about 77% to about 88% glycerol.

Preferably, the lubricant oil comprises from about 80% to about 87% glycerol.

Optionally, the lubricant oil comprises a diluent. Preferably, the lubricant oil comprises from about 10% to about 40% diluent. More preferably, the lubricant oil comprises from about 13% to about 20% diluent. Suitably, the diluent comprises water. Alternatively, or in addition, the diluent comprises isopropyl alcohol.

Advantageously, the lubricant oil comprises a tackifier. Preferably, the lubricant oil comprises from about 2% to about 3% by weight of a tackifier. More preferably, the tackifier comprises a hydrophobic tackifier. Suitably, the hydrophobic tackifier comprises Flowtac 2000.

Preferably, the lubricant oil comprises a surfactant/emulsifier. Suitably, the lubricant oil comprises from about 1% to about 2% by weight of surfactant emulsifier.

Advantageously, the surfactant/emulsifier is selected from the group comprising polyethylene glycol (PEG), TPM, polypropylene glycol (PPG), d-Iimonene and ethoxylated alcohol or mixtures thereof. Preferably, the glycerol by-product of biodiesel production has been subjected to a methanol removal process. More preferably, the methanol removal process comprises a distillation process. Most preferably, up to 90% of the methanol present in the glycerol by-product is removed in the methanol removal process.

The invention also extends to a method for the manufacture of a lubricant from the glycerol by-product of biodiesel manufacture comprising:

removing excess methanol from the glycerol by-product;

adding a diluent as required, and

mixing a tackifier as required to obtain a glycerol lubricant having the desired physical properties. Preferably, the lubricant comprises a lubricant oil for mechanised equipment. Suitably, the excess methanol is removed by distillation. Preferably, the diluent comprises water and/or isopropyl alcohol.

Advantageously, the tackifier comprises a hydrophobic tackifier. Preferably, the hydrophobic tackifier comprises Flowtac 2000.

Preferably, the method of the invention further comprises the step of adding a surfactant/emulsifier to the glycerol lubricant. More preferably, the surfactant/emulsifier is selected from the group comprising polyethylene glycol (PEG), TPM, polypropylene glycol (PPG), d-limonene and ethoxylated alcohol or mixtures thereof. In a further embodiment, the invention also extends to the use of glycerol in the manufacture of a lubricant for mechanised equipment.

Preferably, the mechanised equipment comprises chain driven forestry/agricultural equipment.

Suitably, the lubricant comprises a lubricant oil.

In a preferred embodiment, the glycerol comprises the glycerol by-product of biodiesel production.

The invention also extends to the use of glycerol as a mineral oil substitute in lubricating oils. Preferably, the glycerol comprises the glycerol by-product of biodiesel production. Suitably, methanol is removed from the glycerol by-product and, preferably, the methanol is removed by distillation.

As the lubricant of the invention is a by-product of the production of biodiesel, it is cheap to produce. Moreover, the lubricant is environmentally friendly and exceeds the minimum biodegradabiiity requirements of chemicals as defined by the OECD to such an extent that it can be defined as being "readily biodegradable". The lubricant of the invention is formed from the crude glycerol by-product of biodiesel production which can be distilled to remove methanol from the glycerol byproduct. The removed methanol is then effectively replaced by a biodegradable and environmentally friendly diluent such as water in the final product which assists in ensuring a desirable lubricating oil viscosity. Accordingly, the lubricant of the invention is derived from a freely available raw material source so that what would otherwise be considered a waste material can be exploited to manufacture an effective lubricating oil having wide application. Accordingly, the Applicant has arrived at a new and original use for a crude glycerol by-product in the manufacture of an environmentally friendly and readily

biodegradable lubricating oil.

Detailed Description of the Invention

The lubricating oil of the invention can be generally made up of from about 77% to about 88% glycerol, preferably from about 80% to about 87% glycerol, from about 10% to about 20% diluent, preferably from about 13% to about 20% diluent (e.g. water and/or isopropyl alcohol) and from about 2% to about 3% by weight of a tackifier such as Flowtac 2000 (Trade Mark) available from Brad-Chem Limited. The lubricating oil can also include from about 1% to about 2% by weight of a suitable surfactant/emulsifier (or a blend of surfactants/emulsifiers) for stabilising the glycerol/diluent mixture. The glycerol employed in the lubricating oil of the invention is derived from a crude glycerol by-product resulting from the manufacture of biodiesel from spent cooking oil. The crude glycerol by-product can be processed to produce the lubricating oil of the invention using a methanol removal process, preferably a distillation process in which excess methanol present in the crude glycerol by-product is substantially removed e.g. up to 90% of the methanol present is the crude by-product is removed.

The methanol is removed from the crude glycerol product due to its undesirable toxicological and ecological characteristics.

The crude glycerol by-product can vary in the quantity of methanol present in the byproduct according to the biodiesel manufacturing process employed. However, in general, most crude glycerol by-products of biodiesel production will contain from about 10% to about 20% methanol although levels are more frequently in the range from about 12% to about 14% methanol.

In the distillation process of the invention, the crude glycerol product is distilled at a temperature ranging from about 68°C to about 73°C to remove the methanol. A temperature of about 71 °C is preferred. The crude glycerol is generally distilled for a period sufficient to remove up to about 90% of the methanol as required.

Accordingly, where the crude glycerol generally comprises from about 10% to about 18% by weight of methanol, the distillation process of the invention reduces the methanol levels to from about 2% by weight to about 4% by weight which is sufficient to exceed biodegradability standards in the final product. If desired, the glycerol from which the methanol has been removed can be employed as is. However, in a preferred embodiment, the distilled product can be diluted to enhance the physical characteristics such as the viscosity of the product. For example, it has been found that the addition of a diluent at levels ranging from about 10% to about 40% can enhance the performance of the lubricating oil of the invention at various environmental temperatures e.g. in winter months a lubricating oil incorporating a diluent is recommended in order to prevent the lubricating oil from thickening excessively at low temperatures. In general, in the absence of a diluent such as water, the lubricating oil is suitable for use at temperatures down to about -10°C. Surprisingly, it has been found that by adding water to the lubricant at relatively low levels, the operating temperature for the lubricating oil can be reduced to about -18°C.

Suitable diluents include water and isopropyl alcohol either alone or combination although isopropyl alcohol is especially suitable for use at particularly low

temperatures. Typically, water can be used at levels ranging from about 10% to about 40% while isopropyl alcohol can be used at levels ranging from about 10% to about 25%. If desired, a pour point depressant can be added for very low temperature use.

A tackifier can also be mixed with the glycerol to enhance the physical

characteristics of the lubricating oil e.g. to enhance adhesion and prevent "flinging" of the lubricating oil of the invention from equipment such as chainsaw chains in use. Hydrophobic tackifiers are preferred. An example of such a preferred tackifier is the Flowtac 2000 (Trade Mark) available from Brad-Chem Limited referred to above.

Surprisingly, it has been found that although glycerol and diluents such as isopropyl alcohol and water are all water soluble, hydrophobic tackifiers result in a lubricating oil exhibiting optimal performance characteristics that is still water miscible and disposable.

In general, the tackifier can be incorporated into the lubricating oil at levels ranging from about 2% to about 3% by weight.

As indicated above, a suitable surfactant/emulsifier or blend of

surfactants/emulsifiers can be included in the lubricating oil formulation for stabilising the glycerol/diluent mixture, e.g. glycerol and water, and preventing separation of the mixture over extended periods. Suitable surfactants/emulsifiers include polyethylene glycol (PEG), TPM, polypropylene glycol (PPG), d-limonene and ethoxylated alcohol or mixtures thereof.

The resultant lubricating oil incorporating all components namely glycerol, residual methanol (if any) and optional diluents, tackifier and surfactants/emulsifiers is extremely stable with a desirably long shelf life.

As will be appreciated by those skilled in the art, the crude glycerol by-product employed in the lubricating oil of the invention can also contain residues or impurities from the biodiesel production process such as water, KOH and soaps. Surprisingly, the Applicant has therefore arrived at a novel and inventive use for glycerol in the manufacture of a lubricating oil. In particular, the Applicant has identified a heretofore unknown ecologically friendly use for glycerol by-products of biodiesel production which up to now have either been destroyed, composted or digested at considerable expense.

Examples The invention will now be described, by way of example only, with reference to the following drawings and non-limiting Examples in which:

Figure 1 is a graph of the absolute oxygen demand of all treatment groups over 28 Days, and

Figure 2 is a graph of the percent degradation over 28 days.

Example 1 - Methanol Removal Methanol was removed from a 200 L batch of the crude glycerol by-product of biodiesel manufacture as follows.

200 L of the crude glycerol containing approximately 20% methanol was placed in a still having a capacity of approximately 500 L fitted with a reflux tower which was in turn connected to a condenser at its outlet. Three electric immersion-type heaters were used to heat the still - two 3-phase heaters and one single-phase heater.

A temperature gauge was fitted in the still and a temperature probe was fitted at the top of the reflux tower. The temperature probe served to control the single-phase heater via a FID controller and maintain an even temperature in the still as required.

The two 3-phase heaters were first activated and the temperature probe was set at 71^eC. When the temperature reached a temperature between 53°C and 58^eC as detected by the temperature probe, one of the 3-phase heaters was switched off and heating continued until the temperature probe detected the pre-set temperature of 71°C.

It should be noted that the methanol can start to distil off at a temperature of approximately 58^eC although optimal distillation occurs from approximately the mid 60's °C to about the pre-set temperature of about 71 °C.

Upon reaching the pre-set temperature of 71 °C, the remaining 3-phase heater was switched off and the single-phase heater was switched on. The single-phase heater served to maintain the distillation temperature at 71°C by heating the still as required in response to the temperature detected by the temperature probe.

The distillation flow rate ranged from about 12 to about 18 L methanol/hour with the 3-phase heater switched on, to between 4 and 5 L methanol/hour with the 3-phase heater switched off and the single-phase heater switched on. Distillation was continued for five hours until approximately 90% of the methanol present in the crude glycerol by-product was removed i.e. approximately 34 L methanol. Example 2 - Lubricating Oil Mixture

Following cooling to approximately 50°C, 112 L of the methanol depleted glycerol was pumped through a filter into a mixing tank having a capacity of 500 L fitted with an electric single-phase mixer.

16.8 L of isopropyl alcohol was added to the glycerol as a diluent together with 96ozs/2.72kg Flowtac 2000 (Trade Mark) tackifier available from Brad-Chem Limited. The mixture was then mixed for approximately one hour.

The resultant lubricating oil therefore contained approximately:

112 L of methanol depleted glycerol* = 85%

16.8 L IPA = 13%

2.7 L Flowtac 2000 = 2%

131.5 L = 100%

*which included approximately 5-7% residual water The parameters described in the above Examples relate to a batch size of 200 L. However, as will be appreciated by those skilled in the art, the parameters can be varied as required in accordance with other batch sizes. Example 3 - Efficacy

The efficacy of the lubricating oil prepared as outlined in Examples 1 and 2 above was demonstrated as follows. A chainsaw was placed in a vice and secured. A mineral oil-based lubricating oil of the prior art was applied to the chainsaw in the conventional manner and a card placed 0.5 metres to the front of the chainsaw bar to catch any fling of oil from the nose of the bar. The chainsaw was activated and the fling recorded on the card. The exercise was then repeated using the lubricating oil of the invention and the fling recorded.

It was observed that the fling pattern created by both lubricants was extremely similar thus demonstrating the analogous physical properties, including viscosity, of the lubricating oils while the chainsaw was clearly lubricated by the lubricant oil of the invention - in particular the bottom rail of the saw bar was efficiently lubricated by the lubricating oil of the invention.

The lubricating oil of the Invention was also highly efficacious at preventing overheating of the saw bar. Example 4 - Biodegradability

The ready biodegradability of the lubricating oil prepared as outlined in Examples 1 and 2 above was assessed employing the Manometric Respiratory Test (OECD Guideline 301 F, Ready Biodegradability, Manometric Respirometry Test) as follows.

- Method

Manometric Respirometer, glass bottles were filled with 250 ml_ of the lubricating oil. The degradability and toxicity of the lubricating oil at a concentration of 100 mg/L was estimated in a mineral medium which was inoculated with microorganisms from a municipal wastewater treatment plant. In order to check the procedure, sodium benzoate was used as a readily degradable reference item at a concentration of 100 mg/L, along with a toxicity control with 100 mg/L lubricating oil and 100 mg/L sodium benzoate.

The system consisted of reaction vessels containing a CO2 absorbing agent, an electro-chemical oxygen generator and a switching manometer. The amount of produced oxygen required to maintain constant gas volume was determined via coulometry. The test over 28 days was performed in a climate controlled chamber. The temperature ranged from 22.28 - 22.98°C with mean temperature of 22.59°C.

Percent degradation was determined as the ratio of the amount of oxygen taken up by the microbial population during biodegradation and the COD/ThOD (Chemical/ Theoretical Oxygen Demand) for the test or reference item. The mineral medium was inoculated with a defined amount of activated sludge from a municipal waste water treatment plant. 500 ml_ brown glass bottles served as reaction vessels. These were filled with 250 mL permanently stirred test media, into which the respective chemicals were added. For CO2 absorbance, the reaction vessels also contained a separate vessel filled with soda lime.

All reaction vessels were stored in an Incubator BSB-Digi device (Selutec GmbH, 72379 Hechingen, Germany) at a temperature between 22.28 - 22.98°C with a mean temperature of 22.59°C. The samples were permanently stirred during the test period. The amount of produced oxygen required to maintain constant gas volume was determined via coulometry over the test period of 28 days. Degradation was determined for the lubricating oil, an inoculum control, a procedure control, an abiotic control and a toxicity control.

As inoculum, activated sludge collected from the aeration tank of the municipal sewage treatment plant of Pforzheim/Germany was used. This sewage treatment plant predominantly processes domestic sewage. The activated sludge was washed in mineral medium three times by centrifugation at 3000 rpm for 10 minutes and was afterwards kept under aerobic conditions for 1 day prior to application.

- Mineral Medium

The mineral medium was prepared from four stock solutions using ultrapure grade water. The final composition was as described in Table 1 : Table 1

Composition of the mineral medium

All chemicals used were of analytical grade.

- Test Medium

The pH of the test medium was 7.4 ± 0.2 and 250 mL were used for the abiotic control. Test medium for all other treatment groups was prepared by addition of activated sludge to the mineral medium. The concentration of activated sludge was adjusted to 30 mg/L.

- Treatment Groups

1. Test item group (test item and inoculum)

2. Procedure control group (reference item and inoculum)

3. Inoculum control group (inoculum)

4. Toxicity control group (test item, reference item and inoculum) For treatment groups 1 - 3 two replicates and for treatment group 4 one replicate were used.

- Procedure

Respective amounts of test item were prepared on glass cover slips of 21*26 mm and given into the respective test vessels (treatment groups 1 and 4). For all test assays 250 ml_ of the respective medium were transferred into the test vessels by using volumetric flasks. The preparation of the individual treatments is summarised in Table 2.

Table 2

Preparation of the test assays

Test vessels were put into the test chamber, and were allowed to acclimatise for about one hour with slightly opened manometer and test vessel lids. Prior to the test start, lids were closed tightly and simultaneously.

The pH was measured in the mineral medium and one additional test item replicate prior to the test start and in all treatment groups after 28 days. The oxygen uptake for each test vessel was measured continuously and recorded at 6 hour intervals as shown in Tabfe 3:

Table 3

Individual Daily Values for Cumulative Oxygen Consumption

- Evaluation of Degradability

The BOD determined at each time was calculated by subtracting the oxygen depletion (mg O2/L) of the inoculum control from that exhibited by the test item. This corrected depletion was divided by the concentration (mg/L) of the test item, to obtain the specific BOD as mg oxygen per mg test item. The percentage

biodegradation was calculated by dividing the specific BOD by the ThOD of the test item, the reference item or a mixture of both:

mg 0 /L (uptake test item) - mg 0 /L(uptake blank)

BOD = = mg 0₉/mg test item test item/L

The ThOD for the reference item was calculated from the elemental composition (CcHnClciNnNanaOoFpSs).

16[2c + l/2(h - cl - 3n)+ 3s + 5/2p + 1/2na - 0]

ThOD = mg 02/mg

MW

where MW = molecular weight.

The ThOD of the reference item sodium benzoate was calculated to be 1.67 mg 02/mg. The COD for the test item was determined to be 1.767 mg Oa/mg. The ThOD of the toxicity control was calculated to be

Hence it was determined to be 1.719 mg 02/mg.

Results

The O2 concentrations in the test vessels were measured at time intervals of 6 h from t = 0 days to t = 28 days. All treatment groups were corrected by the mean value of the inoculum controls. Afterwards, the biochemical oxygen demand (BOD mg 02/mg test item) was calculated as described above. The percent degradation was derived from the BOD, divided by the theoretical oxygen demand (ThODRef, CODTest item or the sum of both). The test item showed a degradation of 84.6 % while the reference item amounted to a degradation of 91.6 % after 28 days. A summary for the respective pass levels is given in Table 4 below.

To exclude an overestimation of oxygen consumption, photometric nitrate and nitrite measurements were performed for each replicate of TG 1 , TG 3 and TG 4 at t = 28 days and nitrification could be excluded as impairing factor. Table 4

Pass levels and overall degradation

In the toxicity control, biodegradation amounted to 79.1 % within 14 days. Thus, according to the test guidelines, the test item had no inhibitory effect on activated sludge microorganisms at the tested concentration of 100 mg/L due to a biodegradation > 25 %.

Measured pH values are shown in Table 5 below:

Table 5

pH Values

"measured in one additional replicate The daily % degradation values are given in Table 6 below while graphical summaries of the absolute oxygen demand and percent degradation are given in Figures 1 and 2.

Table 6

Percentage Degradation

Degradation¹ [%]

Test Item Procedure Control Toxicity Control

[days] Replicate 1 Replicate 2 Replicate 1 Replicate 2 -

0 0.0 0.0 0.0 0.0 0.0

1 18.7 17.6 6.8 8.5 13.7

2 28.3 27.9 50.5 50.6 22.8

3 39.7 38.7 59.3 60.2 30.2

4 46.2 45.2 66.5 69.0 35.1

5 51.8 50.7 72.2 74.7 58.8

6 55.4 54.4 75.8 78.5 62.1

7 59.7 58.8 79.0 80.9 65.6

8 64.0 63.5 81.1 82.8 68.3

9 67.8 66.9 82.4 83.9 70.7

10 70.4 69.2 83.7 85.4 73.0

11 72.8 71.4 85.0 86.5 74.5

12 74.3 73.3 85.1 87.2 75.6

13 76.3 75.0 85.9 87.9 77.4

14 77.8 76.4 86.5 88.4 79.1

15 78.9 77.8 87.0 89.3 80.7

16 80.1 78.3 87.5 89.5 81.6

17 81.1 79.5 87.7 90.5 82.9

18 82.1 80.1 88.1 90.4 83.3

19 82.4 80.6 88.4 91.5 84.2

20 83.6 81.1 88.5 91.6 84.7

21 84.0 81.6 88.9 92.0 85.3

22 84.4 81.9 89.2 92.0 85.7

23 84.9 82.2 89.6 92.4 86.4

24 85.1 82.2 89.6 92.9 86.5

25 85.4 82.4 89.9 92.7 87.0

26 85.7 82.8 90.0 93.3 87.2

27 86.0 83.0 90.2 93.1 87.8

28 86.2 83.0 90.0 93.3 88.0

Mean 84.6 91.6 - Accordingly, the following biodegradation was determined at the end of the 28-day period:

Lubricating Oil (100 mg/L): 84.6 %

Sodium benzoate (100 mg/L): 91.6 %

Since the pass value of > 60 % was reached within 28 days, the lubricating oil of the invention was considered to be readily biodegradable according to OECD Guideline 301 F. Furthermore, the lubricating oil had no inhibitory effect on activated sludge microorganisms at the tested concentration of 100 mg/L.

Accordingly, the lubricant oil of the invention, being readily biodegradable, far exceeded the minimum biodegradability standards required of such materials and in fact, as shown in Table 6, exceeded the basic biodegradability standard of 61% after only eight days.

Claims

1. A lubricant comprising glycerol wherein the glycerol is a by-product of bio- diesel production.

2. A lubricant as claimed In Claim 1 wherein the lubricant comprises a lubricant oil for mechanised equipment.

3. A lubricant as claimed in Claim 2 wherein the lubricant oil comprises from about 77% to about 88% glycerol.

4. A lubricant as claimed In Claim 2 or Claim 3 wherein the lubricant oil comprises from about 80% to about 87% glycerol. 5. A lubricant as claimed in any of Claims 2 to 4 wherein the lubricant oil comprises a diluent.

6. A lubricant as claimed in Claim 5 wherein the lubricant oil comprises from about 10% to about 40% diluent.

7. A lubricant as claimed in Claim 5 or Claim 6 wherein the lubricant oil comprises from about 13% to about 20% diluent.

8. A lubricant as claimed In any of Claims 5 to 7 wherein the diluent comprises water.

9. A lubricant as claimed in any of Claims 5 to 8 wherein the diluent comprises isopropyl alcohol. 10. A lubricant as claimed in any of Claims 2 to 9 wherein the lubricant oil comprises a tackifier.

11. A lubricant as claimed in Claim 10 wherein the lubricant oil comprises from about 2% to about 3% by weight of a tackifier.

12. A lubricant as claimed in Claim 10 or Claim 11 wherein the tackifier comprises a hydrophobic tackifier.

13. A lubricant as claimed in Claim 12 wherein the hydrophobic tackifier comprises Flowtac 2000.

14. A lubricant as claimed in any of Claims 2 to 13 wherein the lubricant oil comprises a surfactant emulsifier. 15. A lubricant as claimed in Claim 14 wherein the lubricant oil comprises from about 1 % to about 2% by weight of surfactant/emulsifier.

16. A lubricant as claimed in Claim 14 or Claim 15 wherein the

surfactant/emulsifier is selected from the group comprising polyethylene glycol (PEG), TPM, polypropylene glycol (PPG), d-limonene and ethoxylated alcohol or mixtures thereof.

17. A lubricant as claimed in any of Claims 2 to 16 wherein the glycerol by- product of biodiesel production has been subjected to a methanol removal process.

18. A lubricant as claimed in Claim 17 wherein the methanol removal process comprises a distillation process. 9. A lubricant as claimed in Claim 17 or Claim 18 wherein up to 90% of the methanol present in the glycerol by-product is removed in the methanol removal process.

20. A method for the manufacture of a lubricant from the glycerol by-product of biodiesel manufacture comprising:

removing excess methanol from the glycerol by-product;

adding a diluent as required, and

mixing a tackifier as required to obtain a glycerol lubricant having the desired physical properties.

21. A method for the manufacture of a lubricant as claimed in Claim 20 wherein the lubricant comprises a lubricant oil for mechanised equipment.

22. A method for the manufacture of a lubricant as claimed in Claim 20 or Claim 21 wherein the excess methanol is removed by distillation.

23. A method for the manufacture of a lubricant as claimed in any of Claims 20 to

22 wherein the diluent comprises water and/or isopropyl alcohol. 24. A method for the manufacture of a lubricant as claimed in any of Claims 20 to

23 wherein the tackifier comprises a hydrophobic tackifier.

25. A method for the manufacture of a lubricant as claimed in Claim 24 wherein the hydrophobic tackifier comprises Flowtac 2000.

26. A method for the manufacture of a lubricant as claimed in any of Claims 20 to 25 further comprising the step of adding a surfactant/emulsifier to the glycerol lubricant. 27. A method for the manufacture of a lubricant as claimed in Claim 26 wherein the surfactant/emulsifier is selected from the group comprising polyethylene glycol (PEG), TPM, polypropylene glycol (PPG), d-limonene and ethoxylated alcohol or mixtures thereof. 28. Use of glycerol in the manufacture of a lubricant for mechanised equipment.

29. Use as claimed in Claim 28 wherein the mechanised equipment comprises chain driven forestry/agricultural equipment.

30. Use as claimed in Claim 28 or Claim 29 wherein the lubricant comprises a lubricant oil.

31. Use as claimed in any of Claims 28 to 30 wherein the glycerol comprises the glycerol by-product of biodiesel production.

32. Use of glycerol as a mineral oil substitute in lubricating oils.

33. Use as claimed in Claim 32 wherein the glycerol comprises the glycerol by- product of biodiesel production.

34. Use as claimed in Claim 33 wherein methanol is removed from the gfyceroi by-product. 35. Use as claimed in Claim 34 wherein the methanol is removed by distillation.