On this global basis, paraffinic base oil supply has been dominated by US-based refiners but as the growth in car sales in China and India surges ahead, Group II/III base oil production is expected to fulfil the market requirement with Group I oil plants being phased out or upgraded to produce Group II oils.
As a result, refiners are already taking steps to increase production with a number of new Group II/III base oil plants recently started up or in construction phase. Consequently, the market place has become more price-competitive with refiners looking for ways to improve efficiencies in their lube oil processes. One way to achieve this is by using accurate and reliable online analysis techniques that reduce give- away and increases the yield of products of higher economic value. There are many different types of on-line/in- line viscometers available on the market, which would seem to fit this requirement.
However, it can be shown that systems that comply with ASTM D 445, allow more precise control of lube oil processes, which can lead to increases in revenue. For example, an error of 1 percent product viscosity that causes a blend adjustment can easily result in increasing product cost by €0.01 a gallon. For a large lubricant manufacturer, this can amount to €900,000 in lost revenue per year.
An example is the use of the process viscosity analyser VISC-4 by BARTEC BENKE. The VISC-4 is a capillary type viscometer where the capillary temperature is controlled to +/-0.02K according to ASTM D 445. The temperature control is the single most important parameter for obtaining accurate and precise Kinematic Viscosity measurements. This is especially true for petroleum products as their rate of viscosity per unit temperature is significantly greater than other products. Thus, a slight variation in temperature can have a very large effect on the viscosity of the fluid.
The VISC-4, with its precise temperature control design, has provided readings that show that the analyser meets and exceeds the requirements of ASTM D 445 (see Figure 1 and Table 1).
Figure 1: VISC-4 Kinematic Viscosity readings @ 100 °C for 150N grade of lube base oil over a 12hr test
Table 1: VISC-4 Kinematic Viscosity readings @ 100°C for different grades of lube base oils over a
12hr test run
From Table 2 and Figure 2, a 0.1K variation in temperature will cause the Kinematic Viscosity to change by 0.56cSt, which represents a 0.52% deviation at the measured value of 108cSt @ 40°C.
Table 2: Deviation of Kinematic Viscosity and Index by Temperature accuracy of ± 0.1 K
Since ASTM D 445 requires a maximum deviation of 0.11%, a +/-0.1K temperature control of any sensor or measuring device will not enable conformance to ASTM D 445.
Figure 2: Kinematic Viscosity/Temperature variation due to +/- 0.1K at 40°C
From the results achieved by the VISC-4, see Table 1 and Figure 1, conformance to ASTM D 445 is achieved.
This excellent and reliable performance allows plant operators to optimise the production of higher value products. Remarkable is the payback time for the VISC-4, which is in the region of only 1 to 2 months.
The VISC-4 is available in several variants for different measurement ranges and temperature ranges: depending on the respective ranges and their combinations, Kinematic Viscosities from 0.7 cSt to 1,000 cSt can be measured at temperatures from 20°C to 100°C.
The VISC-4 is ATEX, CSA and GOST approved for use in zone 1 of hazardous areas (note: other regional certifications also available.)The continuous display of the Kinematic Viscosity, the high temperature precision and the minimised maintenance expenditure show the high process efficiency of the Viscosity Process Analyser VISC-4, which has been confirmed by the tests that have been conducted. Other products that can be measured using the VISC-4 include bunker fuels, gasoils and crude oils.
Figure 3: Kinematic Viscosity/Temperature variation due to +/- 0.1K at 100°C