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Effects of System Materials toward the Breakdown of Lubricants and Low-GWP Refrigerants.

AT-19-005 (RP-1774)

This paper is based on findings resulting from ASHRAE Research Project RP-1774.

INTRODUCTION

As the HVAC&R industry transitions to lower global warming potential (GWP) refrigerants, many research and development programs have been focused on hydrofluoroolefins (HFOs), which have been evaluated as alternative refrigerants to hydrochlorofluorocarbons (HCFC) and hydrofluorocarbons (HFC). The thermal stability of HFOs has been reported along with their compatibility with lubricants, metals, plastics, and elastomers (Minor and Spatz 2008, Koban 2011, Rohatgi 2012, Majurin et al. 2014); however, although there have been in-depth studies on the compatibility of process chemicals with HFC/POE systems (Cavestri and Schooley 1996; Rohatgi 2003, Rohatgi et al. 2012), there are limited published data on the compatibility of process chemicals with the HFO/lubricant systems. Process chemicals, including cleaners, degreasers, coolants, sealants, metal working fluids, brazing fluxes, rust inhibitors, and bearing slushing compounds, may be added directly to air-conditioning or refrigeration systems or may be left as residue after an attempt has been made to remove them from a system component. Some of these chemicals have been shown to cause degradation of refrigerants and/or compressor lubricants and their compatibility with the HFO/lubricant systems needs to be determined to ensure the long-term reliability of air-conditioning and refrigeration equipment. Previous research on the compatibility of process chemicals with R-134a/POE (Rohatgi 2003, Rohatgi et al. 2013) provides a sound knowledge base for the evaluation of HFOs. Most of the alternative lower GWP refrigerants under consideration have been shown to be compatible with polyolester (POE) and polyvinyl ether (PVE) lubricants currently in use, and it is anticipated that many process chemicals currently in use with R-134a/POE will be used with HFO/POE, unless shown to be incompatible by new research data.

In this research project, 25 of the chemicals previously used for compatibility study with R-134a/POE were used for compatibility study with HFO/POE. These chemicals, shown in Table 1, are currently in use or being considered for use with the HFO refrigerant systems.

EXPERIMENTAL METHODS

The refrigerant tested was a low-GWP refrigerant blend of R-32/R-1234yf/R-1234ze at 33.3 weight-percent each. The lubricant tested was a non-additized ISO 22 product representative of commercially used POE lubricant. The moisture content of the POE as analyzed by Karl Fischer coulometry was 98 ppm. The moisture contents of the POE with process chemical before aging are shown in Table 2. The copper, aluminum, and steel catalyst coupons (copper was CDA110 or C11000, steel 1010, and aluminum 1100) were prepared by punching 3.3 x 19.3 mm (0.13 x 0.76 in.) coupons from thin sheets. The coupons were held together by aluminum wire such that the steel and copper were separated by the aluminum. These prepared coupon sandwiches were thoroughly cleaned and kept dry prior to use.

Sealed Tube Preparation

The test tubes were cleaned by first rinsing with deionized water, then two rinses with methanol, and one rinse with toluene. They were dried at 175[degrees]C (347[degrees]F) and kept dry in desiccators prior to use. The metal coupons were first placed in the tube, which was then necked down to a size through which a standard cannula could fit. Next the lubricant, or lubricant with process chemical, was added accurately with a syringe and cannula. The tube was evacuated to 30 microns absolute pressure, followed by accurate charging of refrigerant through condensation from a calibrated gas handling system. Finally, the tube neck was sealed and annealed. The sealed tubes were placed in drilled holes in large aluminum blocks, which were heated in air-circulating ovens.

The process chemicals were used as is, without drying. Each of the selected chemicals shown in Table 1 was dissolved in the POE lubricant at the chosen initial concentrations of 0.1 weight-percent and 1.0 weight-percent (based on lubricant weight). Seven chemicals (polyoxyethylene nonylphenyl ether, propylene glycol, benzotriazole, neutral calcium alky laryl sulfonate, neodecanoic acid, chloroparaffin, and ferric chloride) appeared to be completely soluble or miscible in the POE at room temperature, at both initial concentrations. Five chemicals (triethanolamine, zinc chloride, potassium fluoride, potassium hydrogen fluoride, and sodium nitrite) were completely soluble or miscible at 0.1%, but not at 1.0%. The remaining chemicals were only partially soluble at both concentrations and their mixtures with the POE were kept well stirred before homogeneous representative samples were drawn for sealed tube preparation. For each test condition, triplicate sealed tubes were prepared, each tube containing 1.5 g (0.05 oz) of POE or POE/chemical mixture, 1.5 g (0.05 oz) of refrigerant and one metal coupon sandwich. The sealed tubes were aged in a temperature-controlled oven at 175[degrees]C (347[degrees]F) for 14 days.

Sample Analyses

After aging, the tubes were visually inspected for changes in the color of the lubricant or in the metal surfaces, signs of particulate, precipitate, film formation, metal corrosion, and copper plating. The liquid phase in the sealed tubes was analyzed for total acid number (TAN), by ion chromatography (IC) and by inductively coupled plasma (ICP). Samples with high TAN (greater than 3.0 mg KOH/g) were not analyzed by IC to avoid possible damage to the equipment. Samples that contained high concentration of fluoride (greater than 100 ppm) as determined by IC were analyzed by gas chromatography/mass spectrometry (GC/MS) to identify possible refrigerant decomposition products. The weights of the metal coupons were measured before and after aging, and the weight changes were calculated.

Visual inspections were made on each tube after removal from the oven and cooling to reduce internal pressure. The lubricant in each tube was compared to standard liquid color references, which gave a numerical value for the color from water clear and black in the table. Similarly, changes in the presence of solid particulate, extent of metal corrosion, and formation of copper plating were noted and scaled numerically, as described in Table 3.

The total acid number was determined for the lubricant according to a modified ASTM D664 (ASTM 2017) method. The method was modified to accommodate the small 1 mL 0.03 fl. oz. sample size by reducing the alcoholic KOH titrant concentration from 0.1 Normal to 0.01 Normal. This yielded sufficient sensitivity to determine acid numbers down to 0.1 mg KOH/g with a standard deviation of [+ or -]0.05.

In the determination of anion concentrations by IC, about 1 g (0.035 oz) of the lubricant sample was added to a preweighed cup containing 30 mL (1.8 [in..sup.3]) of deionized water. The water/lubricant mixture was stirred continuously for 24 hours to allow for extraction of halide ions and acid anions from the lubricant. The water extract was then analyzed by IC. The concentrations of halide ions (such as fluoride and chloride), organic acid anions (such as formate, acetate, butyrate, pentanoate, hexanoate, and heptanoate) and inorganic anions (such as nitrate, sulfate, carbonate, and bicarbonate) were obtained by calibrating the ion chromatograph with standard solutions so that the peak areas were proportional to the anion concentrations. The sensitivity of the IC method was 1 ppm for small anions such as fluoride, chloride, acetate, and formate and 10 ppm for large anions such as pentanoate, hexanoate, and heptanoate.

GC/MS was conducted using a capillary column with a nonpolar stationary phase and helium as the carrier gas. A column temperature program was used to separate the components on the GC column, and volatile chemicals were ionized by electron ionization at 70 eV. The ions were then filtered in a single quadrupole mass filter, and ions in the range between 33 and 500 mass/charge units (m/z) were detected. The total ion chromatograms were integrated and the results were expressed as percent area. The percentage peak area for an individual component is the peak area for that component divided by the summed areas of all of the peaks in the chromatogram. Mass percentage of an individual component can be obtained from percentage peak area if every component in the mixture is calibrated to determine its response factor. The calibration was not done in this study. This method allowed for semiquantitation of organic gas species with a molecular mass of at least 33 g/mole (33 Da). The mass spectrum for each individual peak in the chromatography was reviewed and identifications were assigned by comparison to mass spectral libraries and/or interpretation of the spectra. Additional confirmation of the assigned component identities, such as retention time verification with standards or different types of analyses, were not conducted. This GC/MS analysis procedure had sufficient sensitivity to detect very low concentrations of volatile organic compounds. In the analyses conducted, components present at concentrations in the range of 0.001% total peak area or less could be readily distinguished from the baseline and identified.

Spectrochemical analysis by inductively coupled plasma (ICP) was performed according to ASTM-D5185 (ASTM 2018) to determine the metal concentrations (in ppm by weight) in the lubricant. The POE samples were diluted with kerosene and then analyzed by ICP. The lower detection limit for most elemental metals is 1 ppm.

EXPERIMENTAL RESULTS

Visual Inspection

After aging, the tubes were observed for visual changes in the color of the lubricant; the presence of cloudiness, particulate, or deposit; film formation on the tube walls; and corrosion of the metal surfaces and copper plating on the steel coupons. To allow for easy comparison between the different chemicals tested and the controls (POE lubricant without process chemical), numerical values were assigned to the visual observations according to the score keys of Table 3. The numerical values are summarized and shown graphically in Figures 1 through 4.

In this study, the low initial process chemical concentration was 0.1 weight-percent and the high concentration was 1.0% weight-percent. As shown in Figure 1, in the (HFO Blend)/POE system, the change in lubricant color indicative of lubricant decomposition was not observed at the low as well as high concentration in the control and in twelve chemicals (including polyoxyethylene nonylphenyl ether, propylene glycol, sodium gluconate, EDTA, iron (III) phosphate dihydrate, sodium molybdate, sodium paratoluene sulfonate, potassium hydrogen fluoride, trisodium phosphate dodecahydrate, sodium carbonate, neodecanoic acid, and ferric chloride), while five chemicals (benzotriazole, ethanolamine, chloroparaffin, hydroxyethyl cellulose, and sodium palmitate) showed color changes at both concentrations. The remaining eight chemicals (boric acid, potassium hydroxide, triethanolamine, zinc chloride, potassium fluoride, calcium alkylaryl sulfonate, sodium nitrite, and sulfamic acid) showed color changes only when the initial concentration was high. Particulate, deposit, cloudiness, and film on tube walls indicate insolubility of chemical compounds in the refrigerant/lubricant system. As mentioned previously, seven chemicals (polyoxyethylene nonylphenyl ether, propylene glycol, benzotriazole, neutral calcium alkylaryl sulfonate, neodecanoic acid, chloroparaffin, and ferric chloride) appeared to be completely soluble or miscible in the POE at room temperature at both initial concentrations. Five chemicals (triethanolamine, zinc chloride, potassium fluoride, potassium hydrogen fluoride, and sodium nitrite) were completely soluble or miscible at 0.1% but not at 1.0%. The remaining chemicals were only partially soluble at both concentrations. After aging, many chemicals showed increased particulate, deposit, cloudiness, and film, as shown in Figure 2, where the visual score is the sum of the scores for particulate, deposit, cloudiness, and film. Increasing scores may indicate the formation of insoluble reaction products. Other chemicals shown in Figure 3 had decreased visual scores, probably because of increased solubility of the starting chemicals with temperature or their depletion through chemical reactions.

In the (HFO Blend)/POE system, the aluminum coupons remained shiny in all the tests. Visual changes were observed with the copper coupons aged in the presence of zinc chloride, ethanolamine (Figure 4), chloroparaffin, and ferric chloride at both concentrations and in the presence of benzotriazole and boric acid only at the high concentration (Table 4). Visual changes were observed with the steel coupons aged in the presence of zinc chloride, sodium nitrite, chloroparaffin, and hydroxyethyl cellulose at both concentrations, in the presence of EDTA and sodium palmitate at low concentration and in the presence of boric acid, ethanolamine, sulfamic acid, and ferric chloride at high concentration (Table 4).

Total Acid Number (TAN)

The TAN values, which can be indicative of lubricant decomposition if high, are shown in Table 5 and Figures 5 and 6. In the (HFO Blend)/POE system, at the low initial concentration, there were 22 chemicals along with the control that had TAN less than or equal to 1.0 mg KOH/g, while at the high concentration there were only 10 chemicals with TAN < 1.0. The 10 chemicals that resulted in TAN < 1.0 mg KOH/g at both concentrations included polyoxyethylene nonylphenyl ether, propylene glycol, EDTA, sodium molybdate, sodium paratoluene sulfonate, potassium fluoride, potassium hydrogen fluoride, sodium nitrite, sulfamic acid, and sodiumcarbonate, while the three chemicals thatresulted in TAN > 1.0 mg KOH/g at both concentrations were boric acid, potassium hydroxide, and ethanolamine. The high TAN for these three chemicals was likely due to decomposition products, because the TAN of the POE with process chemicals before aging were less than 1.0 mg KOH/g at both concentrations, as shown in Table 5. The remaining 12 chemicals (benzotriazole, sodium gluconate, iron [III] phosphate dihydrate, trisodium phosphate dodecahydrate, triethanolamine, zinc chloride, neutral calcium alkylaryl sulfonate, neodecanoic acid, chloroparaffin, ferric chloride, hydroxyethyl cellulose, and sodium palmitate) had TAN < 1.0 mg KOH/g at 0.1 weight-percent initial concentration and TAN > 1.0 mg KOH/g at 1.0 weight-percent initial concentration. For 3 of these 12 chemicals (zinc chloride, ferric chloride, and neodecanoic acid) the high TAN values were likely due to the presence of the chemicals, because the TAN of the POE with process chemicals before aging was greaterthan 1.0 mg KOH/g. Fortwo chemicals (benzotriazole and iron [III] phosphate dihydrate), although the before aging TAN was greaterthan 1.0 mg KOH/g, there were increases in TAN after aging indicative of chemical reactions. The remaining seven chemicals (sodium gluconate, trisodium phosphate dodecahydrate, triethanolamine, neutral calcium alkylaryl sulfonate, chloroparaffin, hydroxyethyl cellulose and sodium palmitate) had TAN < 1.0 mg KOH/g before aging and TAN > 1.0 mg KOH/g after aging, likely because of the presence of decomposition products.

Effect of Moisture Content on TAN. A review of the moisture contents in the POE with process chemical before aging (shown in Table 2) and the TAN after aging (shown in Table 5) indicated that the TAN remained small (< 0.6 mg KOH/g) for eight process chemicals with moisture levels ranging from 148 to 708 ppm. These chemicals included (polyoxyethylene nonylphenyl ether, propylene glycol, EDTA, sodium molybdate, potassium fluoride, potassium hydrogen fluoride, sodium nitrite, and sodium carbonate). For five process chemicals (benzotriazole, sodium gluconate, ethanolamine, sulfamic acid, and chloroparaffin), moisture level was not a significant factor, because there was a significant increase in TAN without a significant increase in moisture level when the initial chemical concentration changed from 0.1% to 1.0%, while for sodium paratoluene sulfonate both the moisture level and the TAN remained unchanged with the change in the chemical concentration. For the remaining 11 chemicals (boric acid, iron [III] phosphate dihydrate, potassium hydroxide, triethanolamine, zinc chloride, trisodium phosphate dodecahydrate, neutral calcium alkylaryl sulfonate, neodecanoic acid, ferric chloride, hydroxyethyl cellulose, and sodium palmitate), the increase in moisture level corresponded in an increase in TAN when the initial chemical concentration changed from 0.1% to 1.0%. However, whether the increase in TAN was caused by the moisture level through hydrolysis of the lubricant or the reaction between the process chemical and the refrigerant/lubricant system was not determined in this study.

Ion Chromatography Results

IC was conducted to measure the concentrations of halide ions (such as fluoride and chloride); organic acid anions (such as formate, acetate, butyrate, pentanoate, hexanoate, heptanoate); and inorganic anions (such as nitrate, sulfate, carbonate, and bicarbonate). The concentrations of fluoride ions as determined by IC after aging are indicative of refrigerant decomposition except in the case of potassium fluoride and potassium hydrogen fluoride where the concentrations of fluoride may have come from the process chemicals rather than possible refrigerant decomposition. The fluoride ion concentrations are shown in Table 5. In the (HFO Blend)/POE system, there were nine chemicals (polyoxyethylene nonylphenyl ether, propylene glycol, EDTA, sodium paratoluene sulfonate, sodium nitrite, sulfamic acid, sodium carbonate, neodecanoic acid, and hydroxyethyl cellulose) along with the control that showed fluoride [less than or equal to] 100 ppm after aging at both low and high initial concentrations and two chemicals (potassium hydroxide and zinc chloride) that showed fluoride > 100 ppm at both concentrations. Two chemicals, including neutral calcium alkylaryl sulfonate and sodium palmitate had fluoride [less than or equal to] 100 ppm at the low initial concentration and fluoride > 100 ppm at the high concentration. Eight chemicals (benzotriazole, sodium gluconate, boric acid, iron [III] phosphate dihydrate, triethanolamine, trisodium phosphate dodecahydrate, chloroparaffin, and ferric chloride) with fluoride [less than or equal to] 100 ppm and two chemicals (such as sodium molybdate and ethanolamine) with fluoride > 100 ppm at 0.1 weight-percent initial concentration were not analyzed at the 1.0 weight-percent concentration due to their high TANs to avoid possible damage to the ion chromatograph.

The total organic acid (TOA) concentrations along with TAN are indicative of lubricant decomposition. TOA concentrations are shown in Table 5. In the (HFO Blend)/POE system, there were four chemicals (polyoxyethylene nonyl-phenyl ether, potassium fluoride, potassium hydrogen fluoride, and sodium carbonate) along with the control that showed TOA [less than or equal to] 1000 ppm after aging at both low and high initial concentrations and eight chemicals (propylene glycol, potassium hydroxide, sodium molybdate, sodium paratoluene sulfonate, zinc chloride, neutral calcium alkylaryl sulfonate, sodium nitrite, and hydroxyethyl cellulose) that showed TOA > 1000 ppm at both concentrations. Four chemicals (EDTA, sulfamic acid, neodecanoic acid, and sodium palmitate) had TOA [less than or equal to] 1000 ppm at the low initial concentration and TOA > 1000 ppm at the high concentration. Two chemicals (sodium gluconate and ferric chloride) with TOA [less than or equal to] 1000 ppm and seven chemicals (benzotriazole, boric acid, iron [III] phosphate dihydrate, triethanolamine, trisodium phosphate dodecahydrate, ethanolamine, and chloroparaffin) with TOA > 1000 ppm at 0.1 weight-percent initial concentration were not analyzed at the 1.0 weight-percent concentration to avoid possible damage to the ion chromatograph due to their high TANs.

Gas Chromatography/Mass Spectrometry Results

Samples that contained a high concentration of fluoride (greater than 100 ppm) as determined by IC were analyzed by GC/MS to identify possible refrigerant decomposition products. Because samples with high TAN (greater than 3.0 mg KOH/g) were not analyzed by IC to avoid possible damage to the ion chromatograph, they were also not analyzed by GC/MS. The results of GC/MS analyses are shown in Table 6. Figure 7 shows the percentage area of extraneous peaks, which were not present in the standard HFO refrigerant blend. Of the 16 samples analyzed by GC/MS, 11 chemicals (including EDTA at 1.0% initial concentration, iron [III] phosphate dodecahydrate at 0.1%, potassium hydroxide at 0.1%, sodium molybdate at 0.1% and 1.0%, triethanolamine at 0.1%, sodium nitrite at 1.0%, ethanolamine at 0.1%, sodium carbonate at 1.0%, neodecanoic at 1.0%, and hydroxyethyl cellulose at 1.0%) showed extraneous peaks with total areas less than or equal to 0.01% of the total area shown in the gas chromatogram. For four of these chemicals (EDTA at 1.0%, iron phosphate at 0.1%, and sodium molybdate at 0.1% and 1.0%) the extraneous peak areas consisted of only R-1234 isomers. As shown in Table 6, the other five chemicals showed numerous extraneous peaks which maybe reaction and or decomposition products.

Concentrations of Elemental Metals in the Lubricant

The concentrations of the iron, copper, and aluminum detected by inductively coupled plasma (ICP) are shown in Table 7. In the (HFO Blend)/POE system, there were 15 chemicals along with the control that showed total elemental concentrations of Fe+Cu+Al less than 10 ppm. These chemicals included polyoxyethylene nonylphenyl ether, propylene glycol, benzotriazole, sodium gluconate, EDTA, sodium molybdate, sodium paratoluene sulfonate, triethanolamine, potassium fluoride, potassium hydrogen fluoride, sodium nitrite, ethanolamine, sulfamic acid, sodium carbonate, and hydroxyethyl cellulose. Of the remaining 10 chemicals, 7 (boric acid, iron [III] phosphate dihydrate, potassium hydroxide, zinc chloride, neutral calcium alkylaryl sulfonate, chloroparaffin, and ferric chloride) had metal concentrations greater than 10 ppm after aging at both the low and high initial chemical concentrations of 0.1% and 1.0%, while three chemicals (trisodium phosphate dodecahydrate, neodecanoic acid, and sodium palmitate) had high metal concentrations only at the high initial chemical concentration of 1.0%.

Weight Changes of Metal Coupons

The weights of the copper/aluminum/steel coupon sandwiches were measured before and after aging and the percentages in weight change due to aging were calculated (Table 7). In the (HFO Blend)/POE system, all the weight changes were less than 1%, except in the presence of zinc chloride at the high initial chemical concentration of 1.0%, where there was a weight gain of 1.4%.

DISCUSSION

There is no consensus within the HVAC&R industry as to an acceptable or critical TAN value for HFC/POE system (Cartlidge and Schellhase 2003) and the original equipment manufacturers' (OEM) and/or lubricant suppliers' recommendations should always be followed. The limited published "acceptable" values of TAN varied between 0.2 mg (Gibb et al. 1999) and 3.3 mg KOH/g (Koban 2011), the "acceptable" fluoride concentrations were between 120 (Rohatgi 2012) and 240 ppm (SAE 2008), the "acceptable" organic acid concentrations were around 600 ppm (SAE 2008), and the "acceptable" elemental metal concentrations were 10 ppm for copper and 25 ppm for iron (Herbe and Lundqvist 1997). The following analysis protocols and the acceptance criteria shown in Table 8 were based on our own experience conducting numerous sealed tube tests on material compatibility and stability of refrigerant/lubricant systems (Henderson 2000; Rohatgi et al. 2012, 2013; Rohatgi 2016). First, the changes in the visual scores were computed by taking the difference between the scores before and after aging. In the case of particulate, deposit, cloudiness, and film, there were decreases in scores resulting in negative changes, but only positive changes were considered for comparison with the controls. If the changes in visual scores of the samples with chemicals were greater than the changes from the controls by one score point, then the samples were noted as failing. If the changes were less thanor equal to one point from the changes in the controls, then the samples were recorded as passing the visual tests. Pass/fail scores were also assigned to the TAN results by first taking the difference between the TAN values before and after aging. If the changes in TAN values of the samples with chemicals were greater than the changes from the controls by 1 mg KOH per gram, then the samples were noted as failing. If the changes were less than or equal to one mg KOH/g from the changes in the controls, then the samples were recorded as passing the TAN criterion. Similarly, for the changes in TOA, if the changes in TOA values of the samples with chemicals were greater than the changes from the controls by 1000 ppm, then the samples were noted as failing. If the changes were less than or equal to 1000 ppm from the changes in the controls, then the samples were recorded as passing the TOA criterion. For the concentrations of metals as measured by ICP, the changes in metal concentrations were calculated by first summing the concentrations of iron, copper, and aluminum and then taking the difference between this sum before and after aging. Since the concentration of metals in the control sample was zero, if the difference between before and after aging of the chemicals was greater than 50 ppm, then the samples were noted as failing. If it was less than or equal to 50 ppm, the samples were noted as passing.It should be emphasized that the pass/fail criteria of Table 8 are highly subjective and selected mainly to provide ways of comparing and ranking the different samples tested. Different applications require different acceptance criteria and the ones chosen here may either be too lenient or too stringent for a particular application. In addition, although many chemicals have small amounts of chemical reactions, as long as the change in their properties (such as visual, TAN, TOA, concentration of metals, and fluoride ion concentration) conform to the criteria shown in Table 8, they would have a passing score.

Table 9 is a summary of the comparison between the effects of the process chemicals on the (HFO Blend)/POE system and the R-134a/POE system. Three process chemicals (polyoxyethylene nonylphenyl ether, propylene glycol, and potassium hydrogen fluoride) met all the criteria listed in Table 8 and were considered compatible for use at both 0.1 and 1.0 weight-percent concentrations in both the (HFO Blend)/POE system and the R-134a/POE system. Five chemicals (boric acid, potassium hydroxide, trisodium phosphate dodecahydrate, neutral calcium alkylaryl sulfonate, and ethanolamine) failed the TAN and/or TOA and/or metal concentrations criteria and were thus considered as incompatible for use at both 0.1 and 1.0 weight-percent concentrations in both refrigerant/lubricant systems. Three chemicals (zinc chloride, chloroparaffin, and ferric chloride) failed more than two visual criteria and were considered as incompatible for use at both concentrations in both refrigerant/lubricant systems. One chemical (sodium paratoluene sulfonate), which was considered compatible in R-134a/POE system was noted as requiring caution for use in (HFO Blend)/POE system because it failed the film formation criterion. In the (HFO Blend)/POE system, two chemicals (potassium fluoride and sulfamic acid) that were compatible for use at 0.1 weight-percent required caution at 1.0 weight-percent, while four chemicals (benzotriazole, triethanolamine, sodium nitrite, and neodecanoic acid), which were also compatible at 0.1 weight-percent were considered incompatible at 1.0 weight-percent. Four chemicals (EDTA, iron [III] phosphate dihydrate, sodium molybdate, and sodium carbonate) required caution at both concentrations, while the remaining three chemicals (sodium gluconate, hydroxyethyl cellulose, and sodium palmitate) required caution at 0.1% and were considered incompatible at 1.0%.

There were five chemicals that were considered incompatible or requiring caution in the R-134a/POE system but were noted as compatible in the (HFO Blend)/POE system. These chemicals were potassium fluoride, sulfamic acid, triethanolamine, sodium nitrite, and neodecanoic acid all at the low initial concentration of 0.1%.

CONCLUSION

The results from this study have shown that many of the chemicals found in process fluids would react with the R-134a/POE and (HFO Blend)/POE systems. Chemical reactions result in changes in a number of properties, such as darker lubricant color, cloudiness, deposit, film formation, darker metal color, dullness, corrosion, increased TAN, increased TOA, and presence of metals in solution, presence of reaction products (such as fluoride ions in the [HFO blend]/POE system). This study showed that the extent of reaction depends on the chemical and its concentration, while previous studies with R-134a/POE showed that it also depends on the aging temperature and the aging time. However, the decision whether or not a chemical is compatible for use in a refrigeration system is highly subjective and depends on the user, the application, and the equipment. The tests conducted in this project were screening tests and, due to the large number of process chemicals, the test matrix was limited to one low GWP refrigerant blend of R-1234yf/R-1234ze (E/R-32), one non-additized ISO 22 POE lubricant, two concentrations for each of the 25 process chemicals, one aging temperature and one aging time. Because a refrigerant blend of R-1234yf/R-1234ze(E)/R-32 was used, if there was no reaction with a particular process chemical, it could be concluded that the process chemical is compatible for use in R-1234yf, R-1234ze(E), and R-32 independently; however, in the cases where significant chemical reactions occurred it would be difficult to establish whether the process chemical is more reactive in R-1234yf/POE or R-1234ze(E)/POE, or R-32/POE. It has been reported that R-1234ze is more stable than R-1234yf and R-1234yf/R-32 blend with fluoride ion concentrations less than 150 ppm after aging in three different lubricants (mixed acid POE, branched acid POE, and PVE) (Rohatgi 2012). In such cases, follow-up research projects need to be conducted to identify the individual refrigerant within the blend that might be contributing to the chemical reactions with the process chemicals

ACKNOWLEDGMENTS

I would like to express my gratitude to ASHRAE and Technical Committee (TC) 3.2, Refrigeration Chemistry, for funding and supporting this research project and the Project Monitoring Subcommittee for its support and guidance. I would also like to acknowledge the valuable assistance of Rob Clark for his excellent workmanship and insightful discussions.

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DISCUSSION

Rogeh Alnajjar, President, Alpha Commissioning Engineers, Inc., Northbrook, IL: Great presentation. Great materials.

Ngoc Dung (Rosine) Rohatgi, PhD

Member ASHRAE

Ngoc Dung (Rosine) Rohatgi is the president and co-owner of Spauschus Associates, Inc., Bethlehem, GA, USA.
Table 1. List of Chemicals Included for Experimental Study

Chemical Name                 Chemical Formula

Polyoxyethylene nonylphenyl   [C.sub.9][H.sub.19][C.sub.6][H.sub.4]
ether (from RP-1410)          [(OC[H.sub.2]C [H.sub.2]).sub.n]OH
Propylene glycol              C[H.sub.3]CH(OH)C[H.sub.2]OH
(from RP-1158)
Benzotriazole (from RP-1158)  [C.sub.6][H.sub.5][N.sub.3]
Sodium gluconate              [C.sub.6][H.sub.11][O.sub.7]Na
(from RP-1410)
Boric acid (from RP-1410)     [H.sub.3]B[O.sub.3]
EDTA (from RP-1158)           [(H[O.sub.2]CC[H.sub.2]).sub.2]
                              NC[H.sub.2]C[H.sub.2]N[(C[H.sub.2]
                              C[O.sub.2]H).sub.2]
Iron (III) phosphate          FeP[O.sub.4].2[H.sub.2]O
dihydrate (from RP-1158)
Potassium hydroxide           KOH
(from RP-1158)
Sodium molybdate              [Na.sub.2]Mo[O.sub.4]
(from RP-1158)
Sodium paratoluene sulfonate  C[H.sub.3][C.sub.6][H.sub.4]S[O.sub.3]Na
(from RP-1158)
Triethanolamine (from         N[(C[H.sub.2]C[H.sub.2]OH).sub.3]
RP-1158)
Zinc chloride (from           Zn[Cl.sub.2]
RP-1158)
Potassium fluoride            KF
(from RP-1410)
Potassium hydrogen fluoride   KH[F.sub.2]
(from RP-1410)
Trisodium phosphate           [Na.sub.3]P[O.sub.4].12[H.sub.2]O
dodecahydrate (from RP-1410)
Neutral calcium alkylaryl     Ca[(C[H.sub.3][(C[H.sub.2]).sub.m]CH
sulfonate (from RP-1410)      ([C.sub.6][H.sub.5])[(C[H.sub.2).sub.n]
                              S[O.sub.3]).sub.2]
Sodium nitrite (from RP-1410) NaN[O.sub.2]
Ethanolamine                  [C.sub.2][H.sub.7]NO
(from RP-1410)
Sulfamic acid (from           [H.sub.3]NS[O.sub.3]
RP-1410)
Sodium carbonate              [Na.sub.2]C[O.sub.3]
(from RP-1410)
Neodecanoic acid              [C.sub.10][H.sub.20][O.sub.2]
(from RP-1410)
Chloroparaffin                [C.sub.X][H.sub.(2x-y+2)][Cl.sub.Y]
(from RP-1410)
Ferric chloride               Fe[Cl.sub.3]
(from RP-1410)
Hydroxyethyl cellulose        [C.sub.2][H.sub.6][O.sub.2].x
(from RP-1410)
Sodium palmitate              [C.sub.16][H.sub.31]Na[O.sub.2]
(from RP-1410)

Chemical Name                 Chemical Abstract Service
                              (CAS) Number (purity)

Polyoxyethylene nonylphenyl   9016-45-9
ether (from RP-1410)          (liquid; purity unknown;)
Propylene glycol              57-55-6 (liquid; 99% pure)
(from RP-1158)
Benzotriazole (from RP-1158)  95-14-7 (solid; 99% pure)
Sodium gluconate              527-07 (solid; 98% pure)
(from RP-1410)
Boric acid (from RP-1410)     10043-35-3 (solid; ACS
                              reagent)
EDTA (from RP-1158)           60-00-4 (solid;
                              99.5% pure)
Iron (III) phosphate          13463-10-0
dihydrate (from RP-1158)      (solid; purity unknown)
Potassium hydroxide           1310-58-3
(from RP-1158)                (solid; ACS reagent)
Sodium molybdate              7631-95-0 (solid;
(from RP-1158)                98% pure)
Sodium paratoluene sulfonate  657-84-1
(from RP-1158)                (solid; purity unknown)
Triethanolamine (from         102-71-6 (liquid;
RP-1158)                      98% pure)
Zinc chloride (from           7646-85-7 (solid;
RP-1158)                      98% pure)
Potassium fluoride            7789-23-3 (solid;
(from RP-1410)                99% pure)
Potassium hydrogen fluoride   7789-29-9 (solid;
(from RP-1410)                99% pure)
Trisodium phosphate           10101-89-0
dodecahydrate (from RP-1410)  (solid; 98% pure)
Neutral calcium alkylaryl     (liquid; purity unknown)
sulfonate (from RP-1410)
Sodium nitrite (from RP-1410) 7632-00-0 (solid;
                              97% pure)
Ethanolamine                  141-43-5 (liquid;
(from RP-1410)                99% pure)
Sulfamic acid (from           5329-14-6 (solid;
RP-1410)                      99% pure)
Sodium carbonate              497-19-8 (solid; 99.95%
(from RP-1410)                pure)
Neodecanoic acid              26896-20-8
(from RP-1410)                (liquid; prime grade)
Chloroparaffin                63449-39-8
(from RP-1410)                (solid; 70% pure)
Ferric chloride               7705-08-0
(from RP-1410)                (solid; purity unknown)
Hydroxyethyl cellulose        9004-62-0
(from RP-1410)                (solid; purity unknown)
Sodium palmitate              408-35-5 (solid; purity
(from RP-1410)                unknown)

Chemical Name                 References

Polyoxyethylene nonylphenyl   Burdeniuc et al. 2013, 2015
ether (from RP-1410)
Propylene glycol              Kamishima et al. 2012;
(from RP-1158)                Rached 2012
Benzotriazole (from RP-1158)  Rached 2012; Rao
                              et al. 2013
Sodium gluconate              Bergherm 2014;
(from RP-1410)                Hodge et al. 2017
Boric acid (from RP-1410)     Nappa et al. 2014, Minor
                              et al. 2014 a, 2014b
EDTA (from RP-1158)           Leck et al. 2014
Iron (III) phosphate          Wollitz 2013;
dihydrate (from RP-1158)      Taras et al. 2013
Potassium hydroxide           Avril and Collier 2013;
(from RP-1158)                Pigamo et al. 2013, 2016;
                              Bossoutrot and Sedat 2014;
                              Bektesevic et al.
                              2015, Sedat and
                              Bossoutrot 2015, Mukhopadhyay
                              et al. 2015
Sodium molybdate              Kontomaris et al. 2011;
(from RP-1158)                Steele et al. 2016
Sodium paratoluene sulfonate  Kontomaris et al. 2011;
(from RP-1158)                Okamoto and Sasao
                              2013; Seki et al.
                              2014; Mabuchietal. 2017
Triethanolamine (from         Fukasaku 2012; Fukasaku
RP-1158)                      et al. 2012; Matsuura
                              et al. 2014; Sun and
                              Nappa 2015a
Zinc chloride (from           Wangetal. 2013; Sun
RP-1158)                      and Nappa 2015b;
                              Matsumoto et al. 2016;
                              Gill et al. 2017
Potassium fluoride            Avril and Collier 2013;
(from RP-1410)                Sedat and Bossoutrot 2015
Potassium hydrogen fluoride   Phelps and Sturgill
(from RP-1410)                2009
Trisodium phosphate           Nappa et al. 2014
dodecahydrate (from RP-1410)
Neutral calcium alkylaryl     Matsumoto et al. 2016
sulfonate (from RP-1410)
Sodium nitrite (from RP-1410) Fujinami and
                              Yokoyama 2015
Ethanolamine                  Sun and Nappa
(from RP-1410)                2015a
Sulfamic acid (from           Kennoy et al. 2014;
RP-1410)                      Chen et al. 2014
Sodium carbonate              Mahler et al. 2012;
(from RP-1410)                Yamakawa et al. 2013;
                              Fukasaku et al.
                              2014; Nappa et al. 2014;
                              Wang and Tung 2014a
Neodecanoic acid              Rebrovic and Boggess
(from RP-1410)                2015, 2016; Itoh and
                              Kajiki 2015
Chloroparaffin                Handa et al. 2014
(from RP-1410)
Ferric chloride               Mukhopadhyay et al. 2010;
(from RP-1410)                Pham et al. 2010; Nose and
                              Komatsu 2014; Tirtowidjojo et
                              al. 2014; Wang and Tung
                              2014b
Hydroxyethyl cellulose        Bayless 2016
(from RP-1410)
Sodium palmitate              Tazaki et al. 2004;
(from RP-1410)                Tagawa et al. 2012

Table 2. Moisture Contents of POE with Process Chemicals Before Aging

Chemical Name                          Moisture, ppm

Polyoxyethylene nonylphenyl        148ppmat0.1 weight-percent
ether (from RP-1410)               concentration; 196 ppm at 1.0%
                                   weight-percent concentration
Propylene glycol (from RP-1158)    167ppmat0.1 weight-percent
                                   concentration; 170ppmat 1.0%
                                   weight-percent concentration
Benzotriazole (from RP-1158)       159ppmat0.1 weight-percent
                                   concentration; 162 ppm at 1.0%
                                   weight-percent concentration
Sodium gluconate (from RP-1410)    155ppmat0.1 weight-percent
                                   concentration; 152ppmat 1.0%
                                   weight-percent concentration
Boric acid (from RP-1410)          493 ppm at 0.1 weight-percent
                                   concentration; 3659 ppm at 1.0%
                                   weight-percent concentration
EDTA (from RP-1158)                150ppmat0.1 weight-percent
                                   concentration; 164 ppm at 1.0%
                                   weight-percent concentration
Iron (III) phosphate dihydrate     148 ppm at 0.1 weight-percent
(from RP-1158)                     concentration; 521 ppm at 1.0%
                                   weight-percent concentration
Potassium hydroxide                181 ppm at 0.1 weight-percent
(from RP-1158)                     concentration; 595 ppm at 1.0%
                                   weight-percent concentration
Sodium molybdate (from RP-1158)    160 ppm at 0.1 weight
                                   -percentconcentration; 156 ppm at
                                   1.0% weight-percentconcentration
Sodium paratoluene sulfonate       301 ppm at 0.1 weight-percent
(from RP-1158)                     concentration; 281 ppm at 1.0%
                                   weight-percent concentration
Triethanolamine (from RP-1158)     272 ppm at 0.1 weight-percent
                                   concentration; 322 ppm at 1.0%
                                   weight-percent concentration
Zinc chloride (from RP-1158)       292 ppm at 0.1 weight-percent
                                   concentration; 337 ppm at 1.0%
                                   weight-percent concentration
Potassium fluoride (from RP-1410)  300 ppm at 0.1 weight-percent
                                   concentration; 302 ppm at 1.0%
                                   weight-percent concentration
Potassium hydrogen fluoride        263 ppm at 0.1 weight-percent
(from RP-1410)                     concentration; 259 ppm at 1.0%
                                   weight-percent concentration
Trisodium phosphate                681 ppm at 0.1 weight-percent
dodecahydrate (from RP-1410)       concentration; 3383 ppm at 1.0%
                                   weight-percent concentration
Neutral calcium alkylaryl          256 ppm at 0.1 weight-percent
sulfonate (from RP-1410)           concentration; 507 ppm at 1.0%
                                   weight-percent concentration
Sodium nitrite (from RP-1410)      240 ppm at 0.1 weight-percent
                                   concentration; 295 ppm at 1.0%
                                   weight-percent concentration
Ethanolamine (from RP-1410)        314 ppm at 0.1 weight-percent
                                   concentration; 337 ppm at 1.0%
                                   weight-percent concentration
Sulfamic acid (from RP-1410)       242 ppm at 0.1 weight-percent
                                   concentration; 198 ppm at 1.0%
                                   weight-percent concentration
Sodium carbonate (from RP-1410)    247 ppm at 0.1 weight-percent
                                   concentration; 708 ppm at 1.0%
                                   weight-percent concentration
Neodecanoic acid (from RP-1410)    177 ppm at 0.1 weight-percent
                                   concentration; 212 ppm at 1.0%
                                   weight-percent concentration
Chloroparaffin (from RP-1410)      188 ppm at 0.1 weight-percent
                                   concentration; 164 ppm at 1.0%
                                   weight-percent concentration
Ferric chloride (from RP-1410)     189 ppm at 0.1 weight-percent
                                   concentration; 264 ppm at 1.0%
                                   weight-percent concentration
Hydroxyethyl cellulose             305 ppm at 0.1 weight-percent
(from RP-1410)                     concentration; 619 ppm at 1.0%
                                   weight-percent concentration
Sodium palmitate                   203 ppm at 0.1 weight-percent
(from RP-1410)                     concentration; 341 ppm at 1.0%
                                   weight-percent concentration

Table 3. Score Keys for Visual Inspection Results

Visual  Liquid Color      Cloudiness    Particulate
Score

0       Water clear       Clear         No particulate
1       Water clear       Faint; very   Faint; very
        at 1.0 and 1.5    light         small amount
                          cloudiness
2       Water clear at    Light         Small amount
        2.0; very faint   cloudiness
        yellow at 2.5
3       Pale yellow at    Cloudy;       Medium
        3.0; light        medium        amount
        yellow at 3.5     cloudiness
4       Yellow at 4.0;    Very cloudy;  Large, heavy
        yellow-orange at  Heavy         amount
        4.5               cloudiness
5       Light orange at   Extremely     Extremely
        5.0; orange at    heavy         heavy amount
        5.5               cloudiness
6       Orange-brown
        at 6.0; brown at
        6.5
7       Dark brown at
        7.0; brown-black
        at 7.5
8       Black             --            --

Visual  Film Deposit on Tube       Aluminum       Copper
Score   Walls or In Bottom of      Corrosion      Corrosion
        Tube

0       No film                    Shiny          Shiny
1       Faint; very light film or  Dull; dark     Slightly
        deposit on walls and in    gray or dull   dull; slightly
        bottom of tube             with coating   darker color
2       Light film or deposit on   Spot or stain  Dull; darker
        walls and in bottom        on surface     color
        of tube
3       Medium Film or             Black (with    Dull with
        deposit on walls           spots)         stains, film
        and in bottom                             or coating
        of tube
4       Heavy film or              Black;         Black
        deposit on walls           corroded
        and in bottom of
        tube; ring at liquid/gas
        interface
5       Extremely heavy deposit    --             --
        and extremely heavy
        ring
6
7
8       --                         --             --

Visual  Steel           Copper
Score   Corrosion       Plating

0       Shiny           No copper
                        plating
1       Dull; slightly  Lightplating
        darker          or plating on
                        edges
2       Dull; dark      Plating on
        gray            surface
3       Spots or        Heavy
        coating on      copper
        surface         plating
4       Black           --
5       --              --
6
7
8       --              --

Table 4. Summary of Metal Catalyst Visual Observations ([HFO Blend]/POE]

Process Chemical  Chemical       Aging          Copper
                  Concentration                Corrosion

Control           0.1            Before aging  0
                  1.0            After aging   0
                  0.1            Before aging  0
Zinc chloride                    After aging   3
                  1.0            Before aging  0
                                 After aging   1
                  0.1            Before aging  0
                                 After aging   1
Ethanolamine      1.0            Before aging  0
                                 After aging   3
                  0.1            Before aging  0
                                 After aging   2.5
Chloroparaffin    1.0            Before aging  0
                                 After aging   2.5
                  0.1            Before aging  0
                                 After aging   2.5
Ferric chloride   1.0            Before aging  0
                                 After aging   2.5
                  0.1            Before aging  0
                                 After aging   0
Benzotriazole     1.0            Before aging  0
                                 After aging   3
                  0.1            Before aging  0
                                 After aging   0
Boric acid        1.0            Before aging  0
                                 After aging   3
                  0.1            Before aging  0
                                 After aging   0
Sodium nitrite    1.0            Before aging  0
                                 After aging   0
                  0.1            Before aging  0
Hydroxyethyl                     After aging   0
cellulose
                  1.0            Before aging  0
                                 After aging   0
                  0.1            Before aging  0
                                 After aging   0
EDTA              1.0            Before aging  0
                                 After aging   0
                  0.1            Before aging  0
Sodium                           After aging   0
palmitate
                  1.0            Before aging  0
                                 After aging   0
                  0.1            Before aging  0
                                 After aging   0
Sulfamic acid     1.0            Before aging  0
                                 After aging   0

Process Chemical  Visual Observations
                  Aluminum   Steel      Copper
                  Corrosion  Corrosion  Plating

Control           0          0          0
                  0          0          0
                  0          0          0
Zinc chloride     0          1          0
                  0          0          0
                  0          4          0
                  0          0          0
                  0          0          0
Ethanolamine      0          0          0
                  0          3          0
                  0          0          0
                  0          4          0
Chloroparaffin    0          0          0
                  0          4          0
                  0          0          0
                  0          0          2
Ferric chloride   0          0          0
                  0          2.5        0
                  0          0          0
                  0          0          0
Benzotriazole     0          0          0
                  0          0          0
                  0          0          0
                  0          0          0
Boric acid        0          0          0
                  0          3          0
                  0          0          0
                  0          1          0
Sodium nitrite    0          0          0
                  0          2.5        0
                  0          0          0
Hydroxyethyl      0          1          0
cellulose
                  0          0          0
                  0          1          0
                  0          0          0
                  0          2          0
EDTA              0          0          0
                  0          0          0
                  0          0          0
Sodium            0          1          0
palmitate
                  0          0          0
                  0          0          0
                  0          0          0
                  0          0          0
Sulfamic acid     0          0          0
                  0          4          0

Table 5. Summary of TAN, TOA, and Fluoride Ion Concentrations of
Samples after Aging in (HFO Blend)/POE1

Process Chemicals        Concentration  TAN,
                         Weight,%       mg KOH/g
                                        Before     After
                                        aging (3)  aging

Control                  None            0.06       0.30
Polyoxyethylene          0.1             0.07       0.26
Nonylphenyl ether (1)
                         1.0             0.06       0.22
Propylene glycol         0.1             0.04       0.25
                         1.0             0.03       0.62
Benzotriazole (1)        0.1             0.11       0.19
                         1.0             2.08       5.58; 7.27
Sodium gluconate         0.1             0.06       0.66
                         1.0             0.06       7.43
Boric acid (1)           0.1             0.11       3.70
                         1.0             0.28      22.93
EDTA                     0.1             0.14       0.25
                         1.0             0.33       0.43
Iron (III)               0.1             0.18       0.21
phosphate dihydrate
                         1.0             1.52       6.64
Potassium                0.1             0          1.39
Hydroxide
                         1.0             0          4.05
Sodium                   0.1             0.06       0.56
Molybdate
                         1.0             0.05       0.51
Sodium paratoluene       0.1             0.05       1.04
Sulfonate
                         1.0             0.06       0.91
Triethanolamine (1)      0.1             0.04       0.70
                         1.0             0.03       6.05; 5.53
Zinc chloride            0.1             1.24       0.98; 1.12
                         1.0            12.22      12.46
Potassium fluoride       0.1             0.04       0.05
                         1.0             0.01       0.20
Potassium hydrogen       0.1             0.01       0.21
Fluoride
                         1.0             0.01       0.19
Trisodium phosphate      0.1             0.75       1.03
Dodecahydrate
                         1.0             0.02      11.0
Neutral calcium          0.1             0.10       0.81; 0.88
alkylaryl sulfonate (1)
                         1.0             0.48       1.75; 1.17
Sodium nitrite           0.1             0.07       0.45
                         1.0             0.08       0.47
Ethanolamine (1)         0.1             0.06       2.06; 2.82
                         1.0             0.13      10.24; 10.27
Sulfamic acid (1)        0.1             0.09       0.31
                         1.0             0.28       0.82
Sodium carbonate         0.1             0.04       0.06
                         1.0             0.04       0.05
Neodecanoic acid         0.1             0.44       0.91
                         1.0             3.6        3.31
Chloroparaffin (1)       0.1             0.08       1.03; 1.07
                         1.0             0.07       9.59
Ferric chloride          0.1            12.74       0.88
                         1.0            12.04      11.47
Hydroxyethyl             0.1             0.05       0.93
Cellulose
                         1.0             0.10       1.93
Sodium palmitate         0.1             0.08       0.52
                         1.0             0.08       1.49

Process Chemicals        TOA,
                         ppm
                         Before          After aging
                         aging (3)

Control                   91              288
Polyoxyethylene          179              464
Nonylphenyl ether (1)
                         145              488
Propylene glycol         Not available   1111
                         Not available   1988
Benzotriazole (1)        Not available   2074
                         Not applicable  Not analyzed (2)
Sodium gluconate         616              836
                         Not applicable  Not analyzed (2)
Boric acid (1)            93             2951; 2204
                         Not applicable  Not analyzed (2)
EDTA                     Not available    776
                         Not available   1622
Iron (III)               Not available   2016
phosphate dihydrate
                         Not applicable  Not analyzed (2)
Potassium                Not available   1584
Hydroxide
                         Not available   5122
Sodium                   Not available   2118
Molybdate
                         Not available   1447
Sodium paratoluene       Not available   1009
Sulfonate
                         Not available   1287
Triethanolamine (1)      Not available   1057
                         Not applicable  Not analyzed (2)
Zinc chloride            Not available   2131
                         Not available   11,837
Potassium fluoride       416              800
                         100              941
Potassium hydrogen         0              468
Fluoride
                         116              750
Trisodium phosphate      407             1867
Dodecahydrate
                         Not applicable  Not analyzed (2)
Neutral calcium          242             1277
alkylaryl sulfonate (1)
                         421             2143
Sodium nitrite             0             1054
                         116             1621
Ethanolamine (1)         222             2263
                         Not applicable  Not analyzed (2)
Sulfamic acid (1)         24              505
                           6             1013;1012
Sodium carbonate          88              446
                         147              883
Neodecanoic acid           0              840
                           0             1315
Chloroparaffin (1)        95             1127
                         Not applicable  Not analyzed (2)
Ferric chloride            0              897
                         Not applicable  Not analyzed (2)
Hydroxyethyl             142             1099
Cellulose
                         376             2144
Sodium palmitate         462              660
                         421             1300

Process Chemicals        Fluoride
                         Ion
                         Concentration,
                         ppm

Control                    11
Polyoxyethylene             2
Nonylphenyl ether (1)
                            5
Propylene glycol            2
                            4
Benzotriazole (1)          44
                         Not analyzed (2)
Sodium gluconate           54
                         Not analyzed (2)
Boric acid (1)             13; 14
                         Not analyzed (2)
EDTA                       23
                           62
Iron (III)                 85
phosphate dihydrate
                         Not analyzed (2)
Potassium                 391
Hydroxide
                         2593
Sodium                    187
Molybdate
                           19
Sodium paratoluene         19
Sulfonate
                           20
Triethanolamine (1)        64
                         Not analyzed (2)
Zinc chloride            1081
                         3515
Potassium fluoride        322
                         1721
Potassium hydrogen         42
Fluoride
                          303
Trisodium phosphate        24
Dodecahydrate
                         Not analyzed (2)
Neutral calcium            36
alkylaryl sulfonate (1)
                          123
Sodium nitrite             13
                           64
Ethanolamine (1)          719
                         Not analyzed (2)
Sulfamic acid (1)          13
                           14; 7
Sodium carbonate           26
                           91
Neodecanoic acid            6
                           53
Chloroparaffin (1)         29
                         Not analyzed (2)
Ferric chloride            25
                         Not analyzed (2)
Hydroxyethyl               11
Cellulose
                           61
Sodium palmitate           27
                          183

(1.) The two numbers reported are from duplicate tubes.
(2.) Samples were not analyzed due to high TAN.
(3.) Data available from published ASHRAE reports (Rohatgi 2003,
Rohatgi et al. 2013). Data are "Not applicable" when samples were not
analyzed after aging due to high TAN.

Table 6. Composition of Extraneous GC/MS Peaks (1)

Process Chemical       Extraneous Peaks

1.0% Potassium         0.010% R-245fa, 0.005% R-1234 isomer;
hydroxide              0.003% 2-Methylpropene, 0.003% Butanal,
                       0.002% R-356 isomer, 0.001% 2-Butene isomer;
                       0.001% 2-Fluoro-2-Methyl
                       propane, 0.003% unknown
0.1% Zinc chloride     0.008% R-31,.0.005% R-1234 isomer;
                       0.003% 2-methylpropene, 0.001%
                       Difluorodimethylsilane
1.0% Zinc chloride     0.215% R-1234 isomer; 0.212% R-31,
                       0.010% R-1233 isomer, 0.009% 1-Pentene,
                       0.009% 3,4,4-trimethylcyclohexene, 0.008%
                       2-Methylpropene, 0.003% Chloromethane,
                       0.003% Methylene chloride, 0.003% 3-Hexene,
                       0.002% 2-Hexene, 0.002% R-356 isomer,
                       0.002% N-Butane, 0.002% 2-Butene isomer;
                       0.002% Pentane, 0.002% 2-Pentene,
                       0.001% 2-Fluoro-2-Methyl Propane,
                       0.001% 2-Butene isomer, 0.001%
                       1,2-Dimethyl-Cyclopropane,
                       0.001% 2,2,3-Trimethyldecane,
                       0.001% Methylcyclopentane, 0.007% unknown
1.0% Neutral calcium   0.059% R-1234 isomer; 0.004%
alkylaryl sulfonate    R-1233 isomer; 0.001%
                       Difluorodimethylsilane, 0.01%
                       2-Methylpropene, 0.001%
                       F43-10 Decafluoropentane
1.0% Sodium palmitate  9.160% Acetone, 1.472% mixture of
                       C7-C10 branched cyclic species, 0.005%
                       R-1233 isomer, 0.004% mixture of Hydrocarbons,
                       0.001% Difluorodimethylsilane,0.001%
                       R-1234 isomer, 0.001% F43-10
                       Decafluoropentane

(1.) The percentage peak area for an individual component is the peak
area for that component divided by the summed areas of all of the peaks
in the chromatogram. Mass percentage of an individual component can be
obtained from percentage peak area if every component in the mixture
was calibrated to determine its response factor. The calibration was
not done in this study.

Table 7. Summary of Metal Concentrations and Coupon Weight Changes in
(HFO Blend)/POE Systems

Process Chemicals    Concentration  Metal            Coupon Weight
                     weight, %      Concentrations,         Changes,%
                                    Iron  Aluminum  Copper

Control              None             <1   <1       <1       0; 0
Polyoxyethylene      0.1              <1   <1       <1       0; 0
nonylphenyl          1.0               1   <1       <1       0; 0
ether (1)
Propylene glycol     0.1               1   <1       <1       0; 0
                     1.0              <1   <1       <1       0; 0
Benzotriazole        0.1              <1   <1       <1       0; 0
                     1.0              <1   <1       <1      +0.1
Sodium gluconate     0.1              <1   <1       <1       0; 0
                     1.0               1   <1       <1       0
Boric acid (1)       0.1              10   <1       <1       0; 0
                     1.0             369   <1       <1      -0.4
EDTA                 0.1               1   <1       <1       0; 0
                     1.0              <1   <1       <1       0; 0
Iron (III)           0.1              12   <1       <1       0; 0
phosphate dihydrate  1.0             134   <1        2       0; 0
Potassium            0.1              23    3        2       0; 0
Hydroxide            1.0            2692  318        3      -0.7; -0.6
Sodium               0.1               1   <1       <1       0; 0
Molybdate            1.0              <1   <1       <1       0; +0.1
Sodium paratoluene   0.1               1   <1       <1       0; +0.1
Sulfonate            1.0               1   <1       <1      +0.1; 0
Triethanolamine      0.1               3    1       <1       0; 0
                     1.0               1    3       <1       0
Zinc chloride        0.1             549    9        1      -0.2; -02
                     1.0            1945   55        4      +1.4; +0.7
Potassium fluoride   0.1              <1   <1       <1       0; 0
                     1.0              <1   <1       <1       0; 0
Potassium hydrogen   0.1              <1   <1       <1       0; +0.1
fluoride
                     1.0              <1   <1       <1       0; +0.1
Trisodium phosphate  0.1               1   <1       <1       0; 0
dodecahydrate        1.0            2135    4       <1      -0.7
Neutral calcium      0.1             156   <1       <1       0; 0
alkylaryl sulfonate  1.0             552    1       <1       0; 0
Sodium nitrite       0.1               1   <1       <1       0; 0
                     1.0               2   <1        1       0; 0
Ethanolamine         0.1              <1   <1       <1      +0.1; +0.1
                     1.0              <1   <1       <1      +0.7
Sulfamic acid        0.1              <1   <1       <1       0; 0
                     1.0              <1   <1       <1       0; 0
Sodium carbonate     0.1              <1   <1       <1       0; 0
                     1.0              <1   <1       <1       0; 0
Neodecanoic acid     0.1               6   <1       <1       0; 0
                     1.0             340   <1        1      -0.1; -0.1
Chloroparaffin       0.1              20   <1       <1      +0.2; +0.2
                     1.0              62   <1        4      +0.3
Ferric chloride      0.1              25   <1        1      +0.3; +0.2
                     1.0             778   <1       36      +0.5; +0.4
Hydroxyethyl         0.1               5   <1       <1       0; 0
cellulose            1.0               4   <1       <1       0; 0
Sodium palmitate     0.1               1   <1       <1       0; 0
                     1.0             466    2        1       0; -0.1

(1.) The two numbers reported are from duplicate tubes.

Table 8. Summary of Criteria for Pass/Fail Scores in the Ranking of
Chemical Species

Property Measurements         Criteria for Passing

Visuals (color, cloudiness,   Changes in visual scores of the
film, deposit, corrosion of   samples with chemicals were
metals, and copper plating)   less than or equal to changes
                              from the controls by one score point.
TAN                           Changes in TAN values of the
                              samples with chemicals were less
                              than or equal to changes
                              from the controls by 1 mg/KOH per g.
TOA                           Changes in TOA values of the
                              samples with chemicals were less
                              than or equal to changes
                              from the controls by 1000 ppm.
Metals in lubricant           Changes in the sum of the
                              concentrations of steel, aluminum,
                              and copper metals detected in
                              lubricants with chemicals were less
                              than or equal to changes from the
                              controls by 50 ppm.
Fluoride ion concentrations   Concentrations of fluoride ions after
                              aging in the samples with
                              chemicals were less than or
                              equal to fluoride ions after
                              aging in the controls by 100 ppm.

Table 9. Summary of Comparison between (HFO Blend)/POE System and
R-134a/POE System

Process Chemicals       (HFO Blend)/POE at  (HFO Blend)/POE at
                        0.1% concentration  1.0% concentration

Polyoxyethylene         Compatible (1)      Compatible
nonylphenyl ether
Propylene glycol        Compatible          Compatible
Potassium hydrogen      Compatible          Compatible
fluoride
Potassium fluoride      Compatible          Caution (2)
Sulfamic acid           Compatible          Caution
Benzotriazole           Compatible          Incompatible
Triethanolamine         Compatible          Incompatible
Sodium nitrite          Compatible          Incompatible
Neodecanoic acid        Compatible          Incompatible
Sodium paratoluene      Caution (2)         Caution
sulfonate
EDTA                    Caution             Caution
Iron (III) phosphate    Caution             Caution
dihydrate
Sodium molybdate        Caution             Caution
Sodium carbonate        Caution             Caution
Sodium gluconate        Caution             Incompatible (3)
Hydroxyethyl cellulose  Caution             Incompatible
Sodium palmitate        Caution             Incompatible
Boric acid              Incompatible        Incompatible
Potassium hydroxide     Incompatible        Incompatible
Zinc chloride           Incompatible        Incompatible
Trisodium phosphate     Incompatible        Incompatible
dodecahydrate
Neutral calcium         Incompatible        Incompatible
alkylaryl sulfonate
Ethanolamine            Incompatible        Incompatible
Chloroparaffin          Incompatible        Incompatible
Ferric chloride         Incompatible        Incompatible

Process Chemicals       R-134a/POE at 0.1%  R-134a/POE at 1.0%
                        concentration       concentration

Polyoxyethylene         Compatible          Compatible
nonylphenyl ether
Propylene glycol        Compatible          Compatible
Potassium hydrogen      Compatible          Compatible
fluoride
Potassium fluoride      Incompatible (3)    Incompatible
Sulfamic acid           Caution             Incompatible
Benzotriazole           Compatible          Incompatible
Triethanolamine         Incompatible        Incompatible
Sodium nitrite          Caution             Incompatible
Neodecanoic acid        Incompatible        Incompatible
Sodium paratoluene      Compatible          Compatible
sulfonate
EDTA                    Compatible          Caution
Iron (III) phosphate    Caution             Incompatible
dihydrate
Sodium molybdate        Incompatible        Incompatible
Sodium carbonate        Incompatible        Incompatible
Sodium gluconate        Caution             Incompatible
Hydroxyethyl cellulose  Caution             Incompatible
Sodium palmitate        Incompatible        Incompatible
Boric acid              Incompatible        Incompatible
Potassium hydroxide     Incompatible        Incompatible
Zinc chloride           Incompatible        Incompatible
Trisodium phosphate     Incompatible        Incompatible
dodecahydrate
Neutral calcium         Incompatible        Incompatible
alkylaryl sulfonate
Ethanolamine            Incompatible        Incompatible
Chloroparaffin          Incompatible        Incompatible
Ferric chloride         Incompatible        Incompatible

(1.) Compatible when meeting all the criteria listed in Table 8.
(2.) Caution when failing one or two visual criteria.
(3.) Incompatible when failing more than two visual criteria or failing
TAN, TOA, metals, or fluoride.
COPYRIGHT 2019 American Society of Heating, Refrigerating, and Air-Conditioning Engineers, Inc. (ASHRAE)
No portion of this article can be reproduced without the express written permission from the copyright holder.
Copyright 2019 Gale, Cengage Learning. All rights reserved.

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Publication:ASHRAE Transactions
Date:Jan 1, 2019
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