使用FluidScan和均匀制剂的准备，以测量涡轮和工业油中的总水污染

A very serious issue in turbine and other industrial oils is water contamination, and water testing forms a part of any lubricant condition monitoring program. Turbine oils normally are formulated to have oxidation resistance, high thermal stability, and exceptional water separation.

专门用于蒸汽轮机或燃气轮机的市售的润滑剂是用特定的添加剂配方制造的，但也有许多油脂可以与不同类型的涡轮机起作用。燃气轮机倾向于积聚污泥和清漆，而蒸汽轮机可能会经历泡沫，氧化和污泥。但是，涡轮系统中的水污染是一个问题。严重的水污染会导致油的粘度，添加剂耗竭，加速氧化和降低轴承寿命的变化。涡轮制造商通常建议警告警报限制<1000 ppm。

在油中检测水的最广泛接受的技术是Karl Fischer（KF）Coulometric滴定（ASTM D6304）¹。这种滴定技术相当麻烦，因为它需要危险的试剂，细致的样品制备，昂贵的设备以及至少每分钟分析。2020欧洲杯下注官网然而，当熟练的操作员执行水时，Karl Fischer分析水可以产生可重复且高度准确的结果，并且是用于水测定的其他分析技术的比较技术。此外，水不必完全溶解在油中。

这流体扫描手持式红外分析仪可以通过在红外吸光度谱的基线中的升力来发现油滴的光散射。图1说明了用过的涡轮机油样品的不同类型的流体扫描光谱，水污染水平增加。

图1。用二手涡轮机油的流体扫描光谱，被用水污染了监视发电厂的真空脱水过程

由油中的水混合物引起的光散射程度取决于那里的水的浓度，但它也受到物理分散在油中的方式的影响：离散水滴的大小和数量如图2所示，存在于油中。

图2。由于水滴变化，二手涡轮机油中光散射的图形表示。光谱A是二手涡轮机，在均质化后立即分析了29,000 ppm的水污染。Spectrum B是一种二手涡轮机油，其均质化后立即分析了9,500 ppm的水污染。光谱C是与A（29,000 ppm）中的样本相同的样本，但均质化后允许静置45分钟。浓度和水滴尺寸的变化在基线提升程度上显而易见。

这refore, it is vital to have representative, homogeneous sampling. At the sampling site, a portable instrument such as the FluidScan can be used for instant results where the water and oil will be homogeneous due to the tumultuous motion within the instrument. If the samples are allowed to settle, perhaps during transit to a laboratory or designated oil analysis site, the water will sooner or later separate as shown in Figure 3. After the water has fully separated from the oil, it is complicated to obtain an accurate measurement of the water content.

图3。从发电厂发货后收到的二手雪佛龙GST 32样品

方法

A new water calibration, which measures light scattering because of the presence of water droplets, is provided on the流体扫描用于工业图书馆。该技术是由众多流行品牌的涡轮和齿轮/轴承油的水污染样品创建的，用于对工业液体的强烈通用校准，范围从1,000 ppm到65,000 ppm的水。该技术的重要组成部分是使用均质器。图4显示了样品用市售的机械均匀均匀的均质，并在室温下静止两分钟（不超过30分钟），然后测量流体扫描。

图4。匀浆水污染的油

结果

使用500 ppm到10,000 ppm的水污染范围的16个样品用于测试针对Karl Fischer D6304的总水流体测量。每个样品是通过在分析前将其匀浆在高高的30秒的情况下制备。它们在三个流体范围和Karl Fischer上同时测量，以减少采样误差的效果。图5显示了结果。

图5。Comparison of the new total water measurement on the FluidScan to ASTM D6304 Karl Fischer titration method

为了证明均质剂在确定工业液中的重要性，该工业流体是为了出色的水分可分离性，由13个服务中的雪佛龙GST组成的测试套件，来自发电厂中的32个油样样品，并没有合适的均质化测试。

图6显示了A组，其中样品在高高的高均匀均匀。在分析之前，将样品瓶轻轻倒20次以混合。

图6。在高均质上均质30秒后显示的样品

图7显示了B组，其中样品用手强烈摇动30秒，然后休息几分钟，以使气泡消散。在测试之前，将样品瓶轻轻倒20次以混合。

图7。Sample which was shaken vigorously by hand for 30 seconds. To the eye, the opacity looks similar to the homogenized samples even though the water is not uniformly dispersed in the sample.

从瓶中的中部填充了塑料一次性移液器，并使用相同的等分试样将液体分配到KF小瓶中，并将其分配到流体扫描翻转式电池中。结果可以在图8中查看。

图8。这samples prepared with a homogenizer showed great agreement between the calculated water concentration on the FluidScan and Karl Fischer result. The samples that were shaken by hand were not accurate.

Evidently, the sample preparation technique has a large influence on the results. All samples prepared only with strong hand-shaking (Method B) had an unacceptably huge number of errors, and in fact, never measured more than 6,000 ppm water on the FluidScan. Although the hand-shaken sample looked opaque, similar to the homogenized samples, a hand-shaken blend of oil with water is not actually homogenous. For at site analysis, a fresh oil sample measured directly at the sampling site should be homogeneous with even water droplet size from the turbulence and shearing within the machine.

特别是在涡轮机油中，水污染的临界限制在约500 ppm的范围内。由于测量对基线漂移很敏感，因此，为了在此范围内提供所需的精度，必须在测量每个样品之​​前对仪器进行巨大护理。至少必须在每次测量之前进行新的背景。此外，必须实施一些清洁度阈值，以寻找牢房中存在残留油的阈值。采用“空气”背景和“空单元”背景也可能会有所帮助。

Measurements of Mobil DTE 732 samples with increasing quantities of water contamination present were taken on a number of spectrometers over several days. Samples were measured in randomized duplicates on each unit on each device, homogenizing the sample for 60 seconds each time before measurement on the FluidScan and by KF. The average results (Figure 9) received over the four days of testing for a single spectrometer, Unit 1, shows the superior linearity of reaction to the technique.

图9。在单元1获得的四天内，每个Mobil DTE 732样品的平均水结果

涡轮机油的液体扫描测量结果严重水污染

表1列出了对所有五个流体扫描单元进行的所有测量结果的综合结果。在每个单元中，在测试的几天中，重复性平均为100 ppm（1*STD）。该技术在所有五个单元上都表现良好，每次测量值<150 ppm（1*std）。很明显，可以在500至1000 ppm的范围内获取可操作的数据。

表格1。此处显示了来自具有不同水污染水平的Mobil DTE 732样品的多天的结果。

一日度测量		样品A，kf = 0 ppm					样品B，KF = 205 ppm					Sample C, KF = 470 ppm					样品D，KF = 1005 ppm
		单元1	单元2	单元3	单元4	单元5	单元1	单元2	单元3	单元4	单元5	单元1	单元2	单元3	单元4	单元5	单元1	单元2	单元3	单元4	单元5
1	1	0	158	0	0	94	244	244	297	270	240	343	428	506	390	536	1139	1038	1164	1223	1061
	2	0	0	0	78	76	136	167	324	297	163	481	470	437	400	103	1060	1081	1204	1299	1117
2	1	9	239	85	156	66	183	201	286	122	233	494	404	561	601	423	915	909	1281	1134	1098
	2	71	27	207	213	0	160	264	183	373	200	705	496	808	675	657	942	962	1075	1092	1156
3	1	101	0	82	85	23	170	0	279	276	91	238	110	409	353	394	988	823	1020	1212	857
	2	0	0	50	67	0	234	141	83	312	298	428	387	621	603	354	1132	1079	1056	1253	1143
4	1	0	0	0	0	80	36	0	130	115	0	309	348	436	457	453	941	655	1007	906	749
	2	78	54	131	195	127	61	33	339	107	109	505	345	416	536	466	841	617	1059	1023	894
AVE		33	60	69	99	59	153	131	240	234	167	438	373	524	502	424	995	895	1108	1143	1010
Stdev		41	84	69	77	43	74	107	96	104	96	145	119	137	118	160	107	183	97	131	154

结论

这new FluidScan technique for investigation of water contamination in turbine oils is a powerful, reliable technique provide an immediate alert of severe water contamination. The largest contributor to the disparity is the sampling. Hand-shaking is not enough for gaining a homogeneous sample and dependable results for water measurement on the流体扫描。Instant on-site analysis or the preparation of samples before analysis with a commercially available homogenizer is proposed for the best results. With a best practice sampling method, results correlating within 20% to Karl Fischer can be accomplished. The new FluidScan water calibration provides accurate assessment of the total water contamination in 90% of the industrial library for >300 ppm water in turbine oils and >1000 ppm water in other oils.

参考
1 ASTM D6304参考

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