Mod 4 - Sulfur

Module from the Laboratory Analyst Training Curriculum curriculum.

Module 4 — Sulfur Analysis · Learning Objectives · 1. Compare UV fluorescence and XRF techniques for refinery sulfur determination. · 2. Operate D5453 UV fluorescence analyzer for ULSD and low-sulfur gasoline. · 3. Calibrate and run D2622 WDXRF for mid-range sulfur. · 4. Recognize interferences (halogens, nitrogen) and apply corrections. · 5. Maintain quality control to meet Tier 3 gasoline and ULSD limits. · Sulfur Methods Overview

Method	Principle	Range	Application
ASTM D5453	UV Fluorescence	0.5–8000 mg/kg	Gasoline, ULSD, jet, kerosene
ASTM D2622	WDXRF	3–10,000 mg/kg	Mid-range S, robust matrix
ASTM D4294	EDXRF	17 mg/kg–5 wt%	Field/fast; mid to high S
ASTM D3120	Microcoulometry	<40 mg/kg	Obsolete but still in specs
ASTM D1552	High-Temp Combustion	0.06–8.0 wt%	Crude, heavy resid, coke
ASTM D7039	MWDXRF	5–500 mg/kg	ULSD, low-S gasoline
ASTM D6920	Oxidative Combustion	100 µg/kg–10,000 mg/kg	Wide range distillates
D5453 UV Fluorescence — Operating Points
Parameter	Typical Value
Furnace temperature	1832 °F (1000 °C)
Oxygen flow	450–500 mL/min
Argon/inert carrier	130–160 mL/min
Sample injection	2–20 µL (auto)
Calibration standards	DBT or thiophene in iso-octane
Check standard frequency	Every 10 samples or 1× / hour
D2622 WDXRF — Operating Points
Parameter	Typical Value
X-ray tube	Rh target, 30–50 kV
Count time	100–300 s per sample
Sample cell	Mylar film, 0.15 mil
Calibration range	3 points covering spec range
Matrix correction	Required; density and C/H ratio
Purge	He or vacuum chamber
Regulatory Sulfur Limits
Product	Limit	Reference
Tier 3 Gasoline (avg)	10 mg/kg	EPA 40 CFR 80.1603
Tier 3 Gasoline (cap)	80 mg/kg	Per gallon cap
ULSD (on-road)	15 mg/kg	EPA / ASTM D975
Jet A-1	3000 mg/kg	ASTM D1655
Marine ECA	1000 mg/kg (1000 ppm)	MARPOL Annex VI
Marine global	5000 mg/kg	IMO 2020
No. 2 Heating Oil	500 mg/kg	ASTM D396 (most states)
Interferences & Controls
Interference	Method Impact	Control
Nitrogen	Quenches UV fluorescence	Use N-doped check std; D5453 Method B
Halogens (Cl, Br)	WDXRF peak overlap	Background subtraction, escape peak check
Aromatics	UV background elevation	Proper carrier flow; baseline subtract
Water	Combustion quench	Dry sample, remove free water
Additives (FAME)	Matrix change	Calibrate with matrix-matched standards
Precision Summary
Method	Level	r	R
D5453	10 mg/kg	0.35 mg/kg	0.70 mg/kg
D5453	100 mg/kg	2.5 mg/kg	5.1 mg/kg
D2622	50 mg/kg	3.0 mg/kg	4.5 mg/kg
D2622	500 mg/kg	12 mg/kg	22 mg/kg
D4294	200 mg/kg	14 mg/kg	25 mg/kg
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Source: Laboratory_Analyst_Training_Curriculum_v1.xlsx · Sheet: Mod 4 - Sulfur

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