ASTM D5236-25 PDF

Full title and description

ASTM D5236-25 — Standard Test Method for Distillation of Heavy Hydrocarbon Mixtures (Vacuum Potstill Method). This method specifies a vacuum potstill (low pressure-drop entrainment separator, total takeoff) procedure for producing distillate fractions and residue from heavy hydrocarbon mixtures (initial boiling point >150 °C) for quality evaluation, fraction yield estimation, and preparation of samples for analytical studies.

Abstract

This test method describes the vacuum potstill distillation of heavy crude oils, petroleum distillates, residues and synthetic mixtures to produce standardized distillate fractions and a residue, and to obtain distillation curves expressed as atmospheric equivalent temperatures (AET). The method includes apparatus performance criteria, typical apparatus illustration, and annexes covering sensor calibration, temperature response, dehydration of wet samples, conversion to AET, and determination of wettage. The procedure is intended for characterization and fraction production where conventional atmospheric distillation methods are not appropriate due to high boiling ranges or thermal stability concerns.

General information

• Status: Active standard (D5236-25).
• Publication date: Published in 2025 (standard designation D5236-25; commercial listings indicate release in early April 2025).
• Publisher: ASTM International (Committee D02 — Subcommittee D02.08).
• ICS / categories: Organic chemicals in general — ICS 71.080.01 (petroleum and related products).
• Edition / version: D5236-25 (current active edition).
• Number of pages: 19 pages (standard document length as listed by commercial providers).

Scope

The standard covers vacuum potstill distillation procedures for heavy hydrocarbon mixtures with initial boiling points above 150 °C (300 °F). It specifies distillation conditions and equipment performance criteria for production of gas-oil and lubricating-oil-range fractions and standard residue, and for determining distillation curves to the highest achievable atmospheric equivalent temperature possible by the method. Annexes provide additional test and calibration practices required for reliable operation. The method is explicit that results are not directly comparable with some atmospheric distillation procedures (for example, D2892) and it includes safety warnings concerning hazardous materials used in some apparatus configurations.

Key topics and requirements

• Applicability to heavy crude oils, residues and synthetic heavy hydrocarbon mixtures (initial boiling point >150 °C).
• Use of a vacuum potstill with low pressure‑drop entrainment separator and total takeoff operation.
• Production and specification of standardized distillate fractions (gas oil and lubricating oil ranges) and residue.
• Determination of distillation curves reported as atmospheric equivalent temperature (AET) and guidance on maximum achievable AET (dependent on sample heat tolerance).
• Apparatus performance checks, sensor calibration, and temperature response test methods (Annexes A1–A5).
• Safety and environmental cautions (handling of hazardous materials such as mercury in some apparatus contexts, and general laboratory safety responsibilities).

Typical use and users

Used by petroleum and petrochemical laboratories, refinery laboratories, quality control and product development teams, contract analytical laboratories, and researchers concerned with characterizing heavy crudes, residues, and synthetic heavy hydrocarbon mixtures. Typical applications include yield estimation of boiling-range fractions, preparation of fractions for downstream analyses, and production of residues for asphalt or other uses (with caution regarding heat‑soak effects on properties).

Related standards

Standards commonly referenced with or compared to D5236 include ASTM D2892 (atmospheric distillation of crude oils for cut points up to specified AET), ASTM D86 (distillation of petroleum products — for lighter boiling-range materials), and other ASTM practices for sensor calibration and temperature conversion. Users should consult the referenced annexes in D5236 and the indicated companion distillation standards when selecting methods for particular samples or cutpoint ranges.

Keywords

distillation, vacuum potstill, heavy crude oil, residue, gas oil, lubricating oil, atmospheric equivalent temperature (AET), potstill, fractionation, ASTM D5236-25.

FAQ

Q: What is this standard?

A: ASTM D5236-25 is the ASTM standard test method that defines the vacuum potstill procedure for distilling heavy hydrocarbon mixtures to obtain standardized fractions and residue and to generate distillation curves expressed in atmospheric equivalent temperature.

Q: What does it cover?

A: It covers apparatus, operational conditions, performance checks, and procedures to distill materials with initial boiling points above 150 °C, producing gas-oil and lubricating-oil-range distillates and residues, plus annexed methods for sensor calibration, temperature response, dehydration of wet samples, conversion to AET, and wettage determination.

Q: Who typically uses it?

A: Refinery and petroleum testing laboratories, QC and R&D teams, contract analytical labs, and any organization needing standardized fraction production or high‑temperature distillation curves for heavy oils and residues.

Q: Is it current or superseded?

A: It is the current active edition designated D5236-25 (released in 2025 and shown as active/last-updated in ASTM’s standards listings).

Q: Is it part of a series?

A: D5236 is part of ASTM’s petroleum distillation family of test methods; it is used alongside other distillation standards such as D2892 (atmospheric crude distillation methods) and D86 (distillation of lighter petroleum products) to cover different boiling ranges and test objectives.

Q: What are the key keywords?

A: Heavy hydrocarbon mixtures, vacuum potstill, distillation, residue, gas oil, lubricating oil, atmospheric equivalent temperature (AET), potstill fractionation, ASTM D5236-25.