We are currently looking to conduct comprehensive laboratory testing on the industrial grease used in our electric motor maintenance routines at 50 Degree ambient Temp.
The primary objective of this testing is to evaluate the quality and performance parameters of the grease, verify its authenticity, and ensure its suitability for the electric motor bearings in our facility.
Could you please provide a detailed quotation and information regarding the testing services you offer for lubricating grease? Specifically, we would like to include the following parameters in the scope of testing:
1. Quality & Composition Analysis (e.g., Base Oil Viscosity, Dropping Point, Consistency / NLGI Grade, Penetration Test)
This technical module establishes operational standards for characterizing heavy hydrocarbon fractions (C6+ through C36+) in natural gas testing. Laboratory technicians, measurement engineers, and production chemists will learn to:
Standard natural gas compositions group heavy fractions into lumped pseudo-components (e.g., C6+). Advanced thermodynamic modeling, pipeline custody transfer, and custody dew point management require extended analysis (C7+, C14+, C36+).
Mechanism: Hydrocarbons heavier than Isopentane (n-C5) are retained on a short precut column while light gases (N2, CH4, CO2, C2-C5) pass to the analytical column.
Valve Timing: At a pre-calculated retention time, the switching valve reverses flow across the precut column, backflushing all C6 and heavier molecules as a single consolidated peak into the Thermal Conductivity Detector (TCD).
Assumed Ratio for Property Calculation: Unless characterized, the default C6+ pseudo-component is mathematically split as:
60\%\text C6\text (Hexane)
30\%\text C7\text (Heptane)
10\%\text C8\text (Octane)
Extended C7+, C14+, and C36+ Separation
Hardware: Utilizes a standard Gas Sampling Valve (GSV) coupled with a capillary column (e.g., 100\text m \times 0.25\text mm Dimethylpolysiloxane DB-1 or HP-1) and a Flame Ionization Detector (FID).
Thermal Ramp: Temperature programming starts at low temperatures (-10^\circ\textC to 40^\circ\textC) to focus volatile fractions, then ramps at 5^\circ\textC to 15^\circ\textC/min up to 320^\circ\textC+ to elute heavy alkanes, cycloalkanes, and aromatics.
C36+ High-Temperature GC: Requires high-temperature polyimide-coated or metal capillary columns operating up to 400^\circ\textC with cool on-column injection to avoid thermal degradation of heavy waxes.
3. Sampling Protocols & Contamination Control
Sampling errors disproportionately affect C6+ through C36+ fractions due to phase behavior changes inside sampling vessels.
┌───────────────────────────────┐
│ Heated Probe in Main │
│ Gas Stream Line │
└──────────────┬────────────────┘
│
▼
┌───────────────────────────────┐
│ Heated Regulator System │
│ (Maintain T > Dewpoint +20°F)
└──────────────┬────────────────┘
│
▼
┌───────────────────────────────┐
│ Heated Transport Tubing │
│ (Trace Heating) │
└──────────────┬────────────────┘
│
▼
┌───────────────────────────────┐
│ Constant Pressure Cylinder / │
│ Chromatograph Loop │
└───────────────────────────────┘
Key Rules for High-Fraction Sampling
Maintain Thermal Envelope: Sampling lines and regulators must be heated to at least 15^\circ\textC (30^\circ\textF) above the predicted Hydrocarbon Dew Point (HDP). Drops in line temperature cause retrograde condensation, stripping C14+ and C36+ components from the vapor phase.
Phase Isolation: Ensure liquid entrainment is avoided unless using specialized liquid injection valves for NGL/condensate testing.
Materials: Use sulfinert/silcosteel-treated stainless steel tubing to prevent adsorption of aromatic heavier compounds (C6-C9 aromatics) or trace sulfur compounds.
4. Technical Calculations & Property Assignment
To calculate the Gross Heating Value (BTU/SCF), Specific Gravity, and Compressibility (Z) from an extended GC run, heavy pseudo-components must be properly characterized.
Characterization Steps
Group Quantification: Sum the total area under peakseluting within specified retention windows:
C6 Window: n-C5 elution end to n-C6 elution end.
C7+ Fraction: Sum of all peaks eluting after n-C6.
C14+ Fraction: Sum of all peaks eluting after n-C13.
C36+ Fraction: Residual material eluting after n-C35.
Molecular Weight & Density Matching: Assign physical constants to the split fractions using GPA Standard 2145 physical property tables.
