Heat transfer fluid composition and use
11292949 · 2022-04-05
Assignee
Inventors
Cpc classification
C23F11/149
CHEMISTRY; METALLURGY
C09K5/20
CHEMISTRY; METALLURGY
International classification
C09K5/20
CHEMISTRY; METALLURGY
Abstract
The present invention provides a real, commercially viable alternative to known heat transfer fluids which exhibits essentially the same or improved viscosity profiles and avoids the corrosion problems. The present invention relates to a heat transfer fluid composition comprising between 10 to 80% by weight of a corrosion inhibitor and freeze point depressant dual function agent, and a viscosity reducing agent. Also disclosed are aqueous based heat transfer fluid products and their use in various heating and/or cooling systems.
Claims
1. A heat transfer fluid composition comprising: 30 to 80% by weight of a corrosion inhibitor and freeze point depressant dual function agent; wherein the corrosion inhibitor and freeze point depressant dual function agent is at least one of glycerol, polyglycerol, trimethylglycine, sorbitol, xylitol, maltitol, and lactitol; and 10% to 70% by weight of a viscosity reducing agent selected from potassium formate, potassium acetate, potassium propionate, and mixtures thereof; and wherein the composition does not comprise a diol selected from one or more of propane-1,3-diol (PDO), propane-1,2-diol(MPG), ethylene glycol (MEG), diethylene glycol (DEG), triethylene glycol (TEG), dipropylene glycol (DPD), or tripropylene glycol.
2. The composition according to claim 1, wherein the corrosion inhibitor and freeze point depressant dual function agent is glycerol.
3. The composition according to claim 1 wherein the viscosity reducing agent is potassium formate.
4. The composition according to claim 1, further comprising a sulfamic acid salt.
5. The composition according to claim 4, comprising from 0.1% to 5% by weight of the sulfamic acid salt.
6. The composition according to claim 1, comprising from 25 to 50% by weight of the viscosity reducing agent.
7. The composition according to claim 1, further comprising at least one corrosion inhibitor.
8. The composition according to claim 7, comprising from 1% to 15% by weight of the corrosion inhibitor.
9. The composition according to claim 7, wherein the corrosion inhibitor comprises at least one of: a. a yellow metal protector selected from the group consisting of a triazole derivative, benzotriazole, tolytriazole, mercaptobenzotraizole, and mixtures thereof, b. a first ferrous metal corrosion inhibitor selected from the group consisting of a long chain carboxylic acid salt, decanedioic acid (sebacic acid), octanoic acid (caprylic acid), nonanoic acid (pelargonic acid), isononanoic acid, 2-ethyl hexanoic acid, benzoic acid, and mixtures thereof, c. a second ferrous metal corrosion inhibitor selected from the group consisting of a mineral inhibitor, nitrate salts, nitrite salts, dipotassium phosphate, and mixtures thereof, or d. an aluminium metal corrosion inhibitor selected from the group consisting of a pH buffer, a secondary amine, a tertiary amine, long chain carboxylic acids, secondary or tertiary amine salts, and mixtures thereof.
10. The composition according to claim 1, further comprising a pH control agent.
11. The composition according to claim 10, wherein the pH control agent is at least one of sodium hydroxide and potassium hydroxide.
12. The composition according to claim 1, further comprising triethanolamine.
13. The composition according to claim 1, further comprising a biocide.
14. The composition according to claim 13, wherein the biocide is at least one of benzisothiazolone, methylisothiazolinone, and bis(3-aminopropyl)dodecylamine.
15. The composition according to claim 1, wherein the corrosion inhibitor and freeze point depressant dual function agent is glycerol and is present in an amount of 30-80% by weight; wherein the viscosity reducing agent is potassium formate and is present in an amount of 10-70% by weight and is in the form of a 75% potassium formate aqueous solution; and wherein the composition further comprises: 0.1-5% by weight of sulfamic acid; 1-15% by weight of corrosion inhibitors; 0-2% by weight of triethanolamine; 0-10% by weight a pH control agent; and 0-0.4% by weight of a biocide.
16. The composition according to claim 1, wherein the corrosion inhibitor and freeze point depressant dual function agent is glycerol and is present in an amount of 30-70% by weight; wherein the viscosity reducing agent is potassium formate and is present in an amount of 25-50% by weight and is in the form of a 75% potassium formate aqueous solution; and wherein the composition further comprises: 0.1-2% by weight of sulfamic acid; 2-10% by weight of corrosion inhibitors; 0.1-2% by weight of triethanolamine; 0-10% by weight a pH control agent; and 0-0.4% by weight of a biocide.
17. The composition according to claim 1, having a pH of between 8.5 and 9.5.
18. The composition according to claim 1, further comprising a scale reducer.
19. The composition according to claim 1, further comprising a thermal stabiliser.
20. An aqueous based heat transfer fluid product, comprising the heat transfer fluid composition of claim 1 and water.
21. The product according to claim 20, comprising from 20% and 60% by volume of the heat transfer fluid composition.
22. A heat transfer fluid composition comprising: 20-80% by weight of a corrosion inhibitor and freeze point depressant dual function agent selected from the group consisting of glycerol, polyglycerol, trimethylglycine, sorbitol, xylitol, maltitol, and lactitol; and 10-25% by weight of a viscosity reducing agent selected from the group consisting of potassium formate, potassium acetate, potassium propionate, and mixtures thereof; and between 10% to 35% by weight of a diol.
23. The composition of claim 22, wherein the viscosity reducing agent is potassium formate.
24. The composition according to claim 22, wherein the corrosion inhibitor and freeze point depressant dual function agent is glycerol.
25. The composition according to claim 22, further comprising a sulfamic acid salt.
26. The composition according to claim 22, wherein the diol is at least one of propane-1,3-diol, propane-1,2-diol, ethylene glycol, diethylene glycol, triethylene glycol, dipropylene glycol, and tripropylene glycol.
27. The composition according to claim 22, further comprising a corrosion inhibitor.
28. The composition according to claim 22, further comprising a pH control agent.
29. The composition according to claim 22, further comprising a biocide.
30. An aqueous based heat transfer fluid product, comprising the heat transfer fluid composition of claim 22 and water.
31. The product according to claim 30, comprising from 20% and 60% by volume of the heat transfer fluid composition.
32. A heat transfer fluid composition comprising: 30-40% by weight of glycerol; 10-25% by weight of a 75% potassium formate aqueous solution; 20-35% by weight of propane-1,3-diol; 0.5-2% by weight of sulfamic acid in the form of a sulfamic acid salt; 3-6% by weight of corrosion inhibitors; 0.1-2% by weight of triethanolamine; 8.5-10% by weight of a pH control agent; and 0.1-0.4% by weight of a biocide.
Description
(1) Embodiments of the present invention are now described in more detail with reference to non-limiting examples and comparative data. A number of Tables and Figures are provided, of which;
(2)
(3)
(4)
(5)
EXAMPLES
(6) Reference to w/w % should be understood to refer to weight by weight percentage.
(7) A series of heat transfer fluid compositions, as detailed below, were prepared and tested for the following; 1. Composition Stability—The stability of compositions was determined using thermal cycling between 20° C. and −10° C. The compositions were inspected for turbidity and the presence of undissolved solids. In particular, 50% v/v dilutions of the compositions were made up with de-ionised water and placed in the freezer at −10° C. and incubated at ambient 20° C. for a specified period of time. The solutions were inspected for clarity and presence of undissolved solids before and after each test. 2. Viscosity Profile—The viscosity profile of compositions were determined at a range of temperatures using an Anton-Parr viscometer. 3. Corrosion Protection—particularly preferred heat transfer fluid compositions in accordance with the present invention were tested according to the ASTM-D1384-05 corrosion testing method to the ASTM-D3306-10 standard, in which a rack of metal coupons were immersed in an aerated solution of the heat transfer fluid at 88° C. for two weeks. 4. Susceptibility to Biological Fouling—particularly preferred heat transfer fluid compositions in accordance with the present invention were tested using a repeat challenge testing methodology in which samples of the heat transfer fluid (50 g) were inoculated with microorganisms on a weekly basis for a 6 week period. A mixed suspension (0.2 ml, 10.sup.10 cfu/ml) containing a mixture of gram positive and gram negative bacteria, moulds and yeast was used to inoculate the samples. The extent of growth in each sample was determined each week by streaking both TS-agar and SA-agar nutrient media with the samples and incubating for 3 days at 25° C. 5. Freeze Point—the freeze points of particularly preferred heat transfer fluid compositions in accordance with the present invention were compared using differential scanning calorimetry (DSC). The DSC detects the melting point of the tested dilution. Under ideal conditions the melting point will also be equal to the freezing point of the substance. However, as freezing is a kinetically driven process the actual freezing point may be lower than the melting point. In consequence it can be concluded that for the dilutions tested freezing can, in principle, occur at any temperature below the recorded melting point, as will be appreciated by the person skilled in the art. 6. Hydraulic Efficiency—The pressure drop per 100 meters of pipe of fixed diameter at 0° C. caused by the optimised composition at turbulent flow (Reynold number=5000) was calculated using a standard engineering equations 1-3, recited below,
F=(5000×B)/(A×E) eq 1
C=[F×(πD.sup.2)]×1000 eq 2
Pressure Drop per 100 meter=[0.0791×(A×C2/100)]/[5000.sup.1/4×(π.sup.2×D.sup.5)] eq 3
Parameters; A=Fluid Density (kgm.sup.−3) B=Dynamic Viscosity (Pa.Math.S) C=Volumetric Flow Velocity (Ls.sup.−1) R.sub.e (Reynolds Number)=5000 D=Pipe Radius (m) E=Pipe Diameter (m) F=Mean Velocity (ms.sup.−1) 7. pH Stability—The pH stability of particular preferred heat transfer fluid compositions in accordance with the present invention were assessed using thermal storage experiments in which dilutions of the compositions were heated to 80° C. and the pH changes monitored routinely using a pH electrode over 2 weeks.
Abbreviations
(8) The following abbreviations are used herewith;
(9) MEG—Monoethylene glycol
(10) MPG—Monopropylene glycol
(11) PDO—Bio-derived or petrochemical derived propane-1,3-diol
(12) HTF—Heat transfer fluid
(13) Reference Solutions
(14) Standard MPG, MEG and PDO based heat transfer fluid compositions were used as reference solutions. In each case these were 93% w/w MPG/MEG/PDO and 7% w/w water.
EXAMPLES
(15)
(16) In
(17) Composition Stability
(18) For a HTF composition comprising a dual freeze point depressant and viscosity reducing agent, it is preferable that the viscosity reducing agent remains in solution over a wide temperature range and that precipitation of solids, that would coat heat exchangers leading to a drop in efficiency and degrade elastomeric seals and cause leaks, is avoided. The stability of the example compositions prepared (as detailed in Table 1) were assessed in terms of turbidity and the presence of un-dissolved solids at both room temperature and at −10° C. The results of this study are shown in Table 2.
(19) TABLE-US-00001 TABLE 2 Composition Stability Appearance at Room Composition Number Temperature Appearance at −10° C. KF001 ++ ++ KF002 ++ ++ KF003 ++ ++ KF004 ++ ++ KF005 ++ ++ KF006 ++ +− KF007 +− −− KF008 +− −− KF009 ++ −− KF010 ++ ++ KF011 ++ ++ KF012 ++ ++ KF013 ++ ++ KF014 ++ ++ KF015 ++ ++ KF016 ++ ++ ++ Clear +− Opaque −− Undissolved Solid Present
(20) Compositions using potassium formate alone as a viscosity reducing agent at various levels showed very good composition stability with the solutions remaining clear and free from un-dissolved solids over the temperature range examined. Incorporation of either sodium acetate or sodium propionate in the compositions led to decreased stability. In the case of compositions KF007 and KF009 where a higher concentration of sodium propionate was utilised, significant difficulties with keeping the salt in solution were observed, particularly at low temperatures. As such the use of potassium formate is preferred.
(21) Compositions shown to be clear in appearance at room temperature were tested for corrosion protection according to the ASTM D1384-05/ASTM-D3306-10 test methods. The results of this testing is summarised in Table 3 below.
(22) Corrosion Protection
(23) For a low viscosity HTF composition to provide long term corrosion protection for a variety of metal and mixed metal systems it is crucial that the protection offered by the HTF is measured using a standard corrosion testing protocol. Furthermore, with potassium formate, sodium acetate and propionates known to be corrosive to metals, incorporation of these as viscosity reducing agents in a low viscosity HTF composition would be expected to decrease the corrosion protection offered by the HTF. Various compositions (as detailed in Table 1), containing different ratios of corrosion inhibitors, viscosity reducing agents and a dual freeze point depressant and corrosion inhibitor were tested according to the industry standard corrosion test (ASTM-D1384-05).
(24) TABLE-US-00002 TABLE 3 Corrosion Testing Results Extent of Corrosion Cast Cast Mild Soft Composition iron Aluminium Steel Copper Brass Solder KF001 xx Xx xx x+ x+ xx KF002 xx Xx xx x+ x+ xx KF003 xx Xx xx x+ x+ xx KF004 ++ ++ ++ ++ ++ ++ KF005 xx Xx xx x+ x+ xx KF006 ++ ++ ++ ++ ++ ++ KF010a xx x+ xx x+ x+ x+ KF010b ++ ++ ++ ++ ++ ++ KF012 xx Xx xx x+ x+ x+ KF013 xx Xx xx x+ x+ x+ KF014 xx Xx xx x+ x+ x+ KF015 xx Xx xx x+ x+ x+ KF016 xx Xx xx x+ x+ x+ 2. ++ Coupon Mass Loss within Specification, x+ Coupon mass loss >20 mg <50 mg, xx Coupon mass loss >50 mg
(25) The results of this corrosion testing showed that if potassium formate is to be used as a viscosity reducing agent and the composition is to pass the ASTM-D1384-05/ASTM-D3306-10 corrosion testing standard, glycerol should preferably be included in the composition. For example, replacing the glycerol component in KF004 with either MPG or PDO or a mixture thereof (KF001-KF003) leads to a significant loss in corrosion protection. Furthermore, the results show that replacement of potassium formate with sodium acetate as the viscosity reducing agent does enable the glycerol component of the composition to be replaced with MPG and still retain corrosion protection meeting the ASTM standard (KF006). However, this comes at the expense of both composition stability (Table 2) and viscosity due to the higher viscosity of sodium acetate solutions compared to those of potassium formate. The selection of constituent parts of the HTF composition may depend on the system in which it is intended to be used, and the duration of use in the said system.
(26) Replacing all or part of the glycerol component with PDO may be advantageous as this may lead to a reduction in viscosity due to the fact that PDO is less viscous than glycerol on a % w/w basis. Where potassium formate is used as a viscosity reducing agent, replacement of part of the glycerol content with PDO does provide a composition that passes the ASTM standard. However, by comparing the corrosion testing results from compositions KF010a and KF010b, this was shown only to be the case when sulfamic acid was also included in the composition. The failures in the corrosion testing shown by compositions KF012 and KF013 demonstrates that sulfamic acid is most effective in combination with glycerol. Furthermore, the failures in corrosion testing on compositions KF014, KF015 and KF016 have shown that the ratio of glycerol to potassium formate can be important in terms of corrosion protection regardless of the presence of sulfamic acid.
(27) Freeze Protection
(28) For a low viscosity HTF to be a suitable replacement for either an MEG based HTF or an MPG based HTF, it must provide comparable or better freeze protection in circulation. The total freeze protection offered by a HTF will depend, largely, upon the total % w/w content of freeze point depressant. In compositions KF004 and KF010b the freeze point depressants are glycerol, potassium formate and PDO. The total % w/w content of freeze point depressant in K4004 and KF010b is 82.6 and 84.5% w/w respectively. The total freeze point depressant content of the reference MPG based HTF is 93% w/w.
(29) The freeze protection offered by compositions KF004 and KF010b was investigated using differential scanning calorimetry (DSC). The DSC detects the melting point of the dilutions. Under ideal conditions this will also be equal to the freezing point of the substance. However, as freezing is a kinetically driven process the actual freezing point may be lower than the melting point. In consequence it can be concluded that for the dilutions listed above freezing can, in principle, occur at any temperature below that listed.
(30) The data in Table 4 shows that despite the lower % w/w content of freeze point depressant, the freeze protection offered by KF004 is essentially equivalent to that of a reference MPG based HTF at dilutions of 40% v/v and below. At concentrations greater than 40% v/v an MPG based HTF offers better freeze protection. Surprisingly, the freeze protection offered by KF010b is generally better than that offered by an MPG based HTF despite its lower freeze point depressant load. Furthermore, at concentrations greater than 40% v/v, no melting point was detected at all down to −80° C. for KF010b. This DSC profile indicates that for dilutions greater than 40% v/v, no significant quantities of solid ice are formed at temperatures down to −80° C. For a heat transfer fluid this is significant as it indicates that a pipe bursting effect is unlikely to be observed with KF010b in application at >45% v/v and on exposure to extremely low temperatures.
(31) TABLE-US-00003 TABLE 4 Freeze Point Comparison KF004/KF010b Reference MPG KF004 DSC Melting KF010b DSC Based HTF Melting % v/v Point/° C. Melting Point/° C. Point/° C. 20 −5.51 −5.40 −5.26 30 −10.10 −11.34 −10.66 40 −17.56 −18.68 −18.95 45 −19.15 Not Detected −24.72 50 −23.09 Not Detected −28.57
Viscosity Studies
(32) The viscosity profiles of the example compositions that showed the most favourable corrosion testing data and composition stability were determined. This data is presented in Table 5. In each case the data was obtained on a 40% v/v dilution of the composition. As a reference, the viscosity profile of a typical MPG based HTF is also presented. The viscosity profile of compositions was determined at a range of temperatures using an Anton-Parr viscometer. 40% v/v dilutions (10 ml) were injected into the Anton-Parr viscometer and the viscosity and density recorded at a range of temperatures.
(33) TABLE-US-00004 TABLE 5 Viscosity Comparison KF010b Reference MPG KF004 Dynamic Based HTF Temperature/ Dynamic Viscosity Dynamic Viscosity ° C. Viscosity (mPa .Math. S) (mPa .Math. S) (mPa .Math. S) 20 4.04 3.27 4.32 10 5.64 4.59 6.78 0 8.46 6.82 11.14 −10 13.90 10.89 21.16 −20 24.90 19.38 45.35
(34) As would be expected, replacement of a more viscous component in a composition (such as MPG), with a less viscous component such as potassium formate and or PDO in compositions KF004 and KF010b does lead to a reduction in viscosity compared to a standard MPG based HTF. Replacement of the PDO in KF010b with MEG was examined as a means of further improving the viscosity profile. MEG, on a % w/w basis, is of lower viscosity than PDO. In consequence it was anticipated that the viscosity of KF010b could be reduced by using MEG in the composition. The data in Table 6 shows the viscosity data on a 50% v/v solution of both KF010b and a composition in which the PDO is replaced with MEG (KF011).
(35) TABLE-US-00005 TABLE 6 KF010/KF011 Viscosity Comparison KF011 KF010b Dynamic Temperature/ Dynamic Viscosity ° C. Viscosity (mPa .Math. S) (mPa .Math. S) −5 13.38 11.24 −10 17.46 17.81 −15 23.36 23.52 −20 30.98 32.31
(36) Surprisingly, replacement of PDO with MEG in composition KF010b did not lead to the expected improved viscosity profile. At low temperatures the viscosity of composition KF011 was higher than that of KF010b. This indicates that an interaction between the three main components in composition KF010b, rather unexpectedly, is responsible for some of the drop in viscosity rather than the drop in viscosity being solely due to the replacement of some of the more viscous components (glycerol, MPG or PDO) with some of the less viscous components (potassium formate and monoethylene glycol). That is to say, there is an unexpected synergistic effect on viscosity profile, in a HTF composition comprising glycerol, potassium formate, and PDO.
(37) Further studies on the viscosity profile, and hydraulic efficiency of optimised composition KF010b were conducted and compared to the standard MPG, PDO, glycerol and MEG based HTF's. The data was obtained using dilutions of the three HTF compositions that provide freeze protection to −30° C.
(38) As shown by
(39) TABLE-US-00006 TABLE 7 Hydraulic Calculations Dynamic Pressure Drop per Viscosity Flow Rate (m/s) 100 m (kPa) MEG Reference HTF 4.5 0.540 14.6 30% v/v KF010b 5.5 0.573 16.9 35% v/v MPG Reference HTF 8.7 1.050 53.9 35% v/v
(40) Calculations are based on dilutions of the HTF providing freeze protection to −15° C. flowing through 40 mm diameter pipe at 0° C. with a Reynolds number of 5000.
(41) The data in Table 7 shows that for a given pipe diameter, KF010b will require a lower flow rate and develop a significantly lower pressure drop compared to the reference MPG based HTF at turbulent flow. The data in Table 7 shows that KF010b has a hydraulic performance much more akin to that of an MEG based HTF than an MPG based HTF. In consequence, replacement of an MPG based HTF with KF010b increases the heat transfer efficiency of a system and reduces the energy used to pump the HTF. Furthermore, systems designed to operate with KF010b instead of an MPG based HTF can use smaller pumps and piping of smaller diameter leading to an overall cost saving.
(42) Biological Fouling
(43) Biological fouling of a HTF can lead to fluid degradation, pH changes, an increase in viscosity and a loss of efficiency and corrosion. Any low viscosity HTF must demonstrate equivalent or improved resistance to biological fouling compared to standard MPG, MEG or PDO based HTFs. With optimised composition stability, corrosion protection, viscosity and toxicity profiles observed with compositions KF010B and KF004 the susceptibility of the compositions to biological fouling was examined next. With both compositions containing glycerol, which is known to be susceptible to biological fouling, it is anticipated by the skilled person that compositions KF004 and KF010b would show less resistance to biological growth than a standard MPG based product. In order to test this prejudice repeat challenge test were conducted in which compositions were inoculated with a standard solution on a weekly basis and the extent of biological growth monitored using agar plates. The resistance to biological fouling was judged semi quantitatively using a system from − to +++, where − indicates no biological growth and +++ indicates serious growth. The type of growth (bacterial, mould or yeast) was also determined by this test method. The total duration of the test was six weeks (
(44) Surprisingly the results obtained from the testing showed that the KF004 composition (Sample B) showed a significantly higher resistance to biological fouling than a simple glycerine solution (Sample A) with biological fouling detected only after the 5.sup.th inoculation. As such, compositions according to the present invention overcome a prejudice in the art in relation to use of glycerol leading to unacceptable levels of biological fouling. Furthermore, further optimisation of composition KF011 by including the commercially available biocide Parmetol MBX® at 0.05% w/w makes it possible to provide equivalent biological fouling resistance as a standard MPG based HTF with the same charge of Parmetol MBX®. This is unexpected given the skilled persons understanding that glycerol is susceptible to biological fouling.
(45) pH Stability
(46) Changes in the pH of a HTF can lead to a decrease in the corrosion protection offered by the HTF and accelerate degradation of the HTF. Glycerol, present in both compositions KF004 and KF0010b, is known to be chemically less stable and more susceptible to degradation at elevated temperatures than MPG, MEG or PDO. The degradation of glycerol leads to the formation of acidic compounds which in turn reduce the pH of the HTF. Optimised composition KF010b was tested for pH stability by holding a 50% v/v dilution in water of the composition at 80° C. for 2 weeks. The pH was measured before and after and this data is recorded in Table 8. In addition, compositions including a range of pH buffers were also tested and this data is also presented in Table 8. For the sake of comparison, the data obtained from a heated storage test on the standard MPG based HTF (50% v/v dilution) is also presented.
(47) TABLE-US-00007 TABLE 8 pH Stability Trial Composition pH At Start pH at End Change Reference MPG HTF 8.01 7.90 0.11 KF010b 7.82 7.23 0.60 KF010b + 0.5% w/w 8.84 8.77 0.07 Triethanolamine KF010b + 1.0% w/w 8.95 8.89 0.06 Triethanolamine KF010b + 0.5% w/w 8.76 8.68 0.08 Morpholine KF010b + 1.0% w/w 8.89 8.74 0.15 Morpholine
(48) The data in Table 8 shows that composition KF010b is more susceptible to changes in pH than the reference MPG based HTF. However, incorporation of a suitable pH buffer such as triethanolamine or morpholine between 0.5-1.0% w/w leads to a significant improvement in the pH stability of the composition. The importance of pH stability in use will depend on the application or system the HTF is to be used in, and also the period of use.
Field Trial Example
(49) To further demonstrate some of the flexibility and range of the invention, a specific formulation was made to the composition in Table 9, and a commercial field trial was performed.
(50) TABLE-US-00008 TABLE 9 Field Trial Fluid (KF017) Composition Component Weight % Glycerol 45 Potassium formate (75% solution) 45 Inhibitor additives 9.7 Benzotriazole (0.04), tolyltriazole (0.1), sulphamic acid (0.6), sebacic acid (0.3), trimethylhexanoic acid (2.34), water (5.0), sodium hydroxide (0.86), triethanolamine (0.47) Dye/water 0.3
(51) The KF017 formulation was diluted to a freeze point of −15° C., and the viscosity of the mixture compared to typical heat transfer fluids at the same freeze point protection. The lower viscosity of KF017 when compared to these fluids, and in particular a typical MEG fluid, is shown in
(52) Corrosion protection was recorded as shown in Table 10.
(53) TABLE-US-00009 TABLE 10 Corrosion testing of KF017 ASTM-D1384-05/ASTM- Mass loss/gain D3306-10 Mass loss/gain Metal (mg) Limit (mg) Cast aluminium −13.5 30 max Cast iron +7.5 10 max Mild steel <1.0 10 max Soft solder +25.0 30 max Copper <1.0 10 max Brass <1.0 10 max
Detail of the Field Trial with KF017
(54) KF017 was trialled in a direct substitution test against a typical commercial MPG product (Dowcal™ N). The equipment it was tested on was a chocolate manufacturing line built by MacIntyre Chocolate Systems Limited of Arbroath, Angus, Scotland. The unit was installed by McIntyre and operated by Universal Robina Corporation based in the Philippines. The molten product moves between rollers which are chilled to form an initial skin on the surface of the chocolate. Ideally, this will happen in such a way that this chilling forms a barrier to resist deformation during further processing, but also leaves the chocolate pliable enough to aid its movement along the rollers before a final chilling stage. The line had been designed to produce a maximum of 500 kg of chocolate lentils per hour, but was restricted in its performance and was only able to produce around 250 kg per hour at best. Frequent cutting out of the chiller implied that the need to reach an operating temperature of −25° C. was being hampered by the viscosity of the incumbent product.
(55) KF017 was diluted with deionised water to a freeze point of −36° C., giving an effective operating temperature of about −30° C. (allowing for a 6° C. freeze point buffer). The system was drained of the Dowcal™ N product, flushed clean, and the fluid replaced with the diluted KF017. During the initial trial work, the system delivered an increased operating rate of 360 kg per hour—an increase in the production rate of 44% and there were no stoppages due to equipment cut-out. A pumping problem was noticed that appeared to be the result of cavitation in the fluid from foam issues. While this foam issue was addressed, the system was returned to standard manufacture using the Dowcal™ N, and production dropped back to the 250 kg per hour rate with frequent cut-out.
(56) For the second trial with KFD017 plus a small addition of antifoam (Xiameter AFE-1510), a similar dilution as described above was used. There were no further pumping issues with this formulation. After a steady increase in rate during this second trial phase, the production was able to be ramped up to and maintained at its design capacity (500 kg per hour) with KF017, representing a 100% increase over the previously used fluid (Dowcal™ N).