Refinery Process Fundamentals Curriculum

Module 6 - Treating & Blending

Module from the Refinery Process Fundamentals Curriculum curriculum.

TREATING, SULFUR RECOVERY & PRODUCT BLENDING · Learning Objectives · 1. Explain amine treating chemistry and equipment (absorber, regenerator, flash drum) 2. Describe Merox and caustic treating for mercaptan removal 3. Understand Claus sulfur recovery and tail gas treating 4. Apply product blending principles to meet gasoline, diesel, and jet fuel specifications 5. Identify key product specifications and ASTM test methods · Treating Processes Overview

Process	Feed	Removes	Chemistry/Mechanism	Key Equipment	Products
Amine Treating (MDEA/DEA)	Fuel gas, LPG, H2 recycle	H2S and CO2	Amine + H2S ⇌ Amine sulfide (reversible absorption)	Absorber, regenerator, flash drum, lean/rich exchangers	Sweet gas, acid gas to SRU
Merox (Caustic/Catalyst)	LPG, naphtha, kerosene, jet	Mercaptans (RSH)	RSH + NaOH → NaSR + H2O; NaSR + O2 → RSSR (catalyzed)	Extractor or fixed-bed reactor, caustic circulation	Sweetened product, spent caustic
Caustic Wash	LPG, naphtha	H2S, mercaptans, organic acids	NaOH neutralization: H2S + NaOH → Na2S + H2O	Wash drum or mixing valve + settler	Treated product, spent caustic
Claus Sulfur Recovery	Acid gas from amine regen	H2S → elemental sulfur	2H2S + SO2 → 3S + 2H2O (Claus reaction, staged)	Reaction furnace, waste heat boiler, catalytic converters (2-3)	Liquid sulfur (99.9%), tail gas
TGTU (Tail Gas)	Claus tail gas	Residual H2S, SO2, COS, CS2	Hydrogenation → absorption (SCOT process)	Reactor, quench column, amine absorber	Clean gas to incinerator, >99.5% S recovery
Sour Water Stripper	Sour condensate from units	H2S and NH3	Steam stripping — reverses absorption	Stripping column, overhead condenser	Stripped water (reuse), acid gas to SRU
Product Specifications — Key Fuel Properties
Product	Specification	Key Property	Limit	ASTM Method	Why It Matters
Gasoline	ASTM D4814	Sulfur	10 ppm max (Tier 3)	D5453	Catalyst poison in catalytic converters
Gasoline	ASTM D4814	RVP	7.0-15.0 psi (seasonal)	D5191	Evaporative emissions, hot/cold start
Gasoline	ASTM D4814	RON/MON (AKI)	87/89/91/93 AKI	D2699/D2700	Anti-knock performance
ULSD Diesel	ASTM D975	Sulfur	15 ppm max	D5453	DPF protection, emissions compliance
ULSD Diesel	ASTM D975	Cetane Number	40 min	D613	Ignition quality — affects cold start, noise, emissions
ULSD Diesel	ASTM D975	Cloud Point	Seasonal (-20 to +5°F)	D2500	Operability in cold weather
Jet Fuel (Jet A)	ASTM D1655	Flash Point	100°F min	D93	Fire safety in handling and storage
Jet Fuel (Jet A)	ASTM D1655	Freeze Point	-40°F max	D5972	Fuel system operability at altitude (-65°F at FL400)
Jet Fuel (Jet A)	ASTM D1655	Sulfur	0.30 wt% max	D4294	Turbine hot section corrosion
Source: FOS Chief Files — Module 13 (Treating), Module 12 (Sulfur Recovery), Refinery_Product_Specifications_v1.xlsx

Source: Refinery_Process_Fundamentals_Curriculum_v1.xlsx · Sheet: Module 6 - Treating & Blending

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