UOP 209-00 PDF

Full title and description

UOP 209-00 — Alkalinity, Sulfide and Mercaptide Analyses of Used Refinery Caustic Solutions. This method describes procedures for determining strong base, weak base (spent caustic) and total alkalinity by potentiometric titration (Part A) and for determining sulfur present as sodium sulfide and sodium mercaptide (Part B). The procedures are intended for quantitative analysis of used refinery caustic solutions encountered in refinery operations and process control.

Abstract

This standard provides laboratory methods for measuring the alkalinity components and sulfur species in used refinery caustic solutions. Part A covers a potentiometric titration approach to separate and quantify strong base, weak base (spent caustic) and total alkalinity. Part B covers chemical determinations for sulfide and mercaptide concentrations. Results are intended to be quantitative over concentrations commonly found in refinery caustic streams; samples are noted to be chemically unstable and should be analyzed promptly after collection.

General information

• Status: Published standard (active method document as of original issuance).
• Publication date: 01 January 2000.
• Publisher: UOP LLC (A Honeywell Company).
• ICS / categories: Petroleum refining and petrochemical laboratory methods; chemical analysis of process streams (petroleum-related analytical methods).
• Edition / version: 209-00 (original 2000 issue).
• Number of pages: 16 pages.

Scope

Defines laboratory procedures for the analysis of used refinery caustic solutions removed from operations such as sweetening, sour gas/mercaptan removal, and other refinery treatment processes. The methods quantify alkaline strength (strong and weak bases) and measure sulfur present as sulfide and mercaptide. The standard emphasizes timely analysis because refinery caustic samples can change composition after sampling. Intended uses include process control, troubleshooting, charge assessment, and laboratory quality assurance.

Key topics and requirements

• Part A — Potentiometric titration to distinguish and quantify strong base, weak base (spent caustic) and total alkalinity.
• Part B — Chemical determinations for sulfur species: sulfide and mercaptide concentrations.
• Sample handling requirement: analyze samples as soon as possible due to instability of refinery caustic solutions.
• Quantitative performance: methods designed to be quantitative over concentration ranges commonly encountered in refinery streams.
• Includes an appendix with a double-indicator caustic solution analysis for convenient plant control checks (non-rigorous alternative).

Typical use and users

Laboratory analysts in refinery process-control and quality departments, refinery technical service groups, environmental and compliance laboratories, and consultants working on caustic regeneration or treatment unit optimization. Typical use cases include routine monitoring of spent caustic strength prior to regeneration or disposal, troubleshooting souring/mercaptan removal performance, and verifying process chemistry during operational changes.

Related standards

Other UOP methods for refinery stream analysis and treatment are commonly referenced alongside UOP 209-00 (for example, various UOP methods covering sampling, titrations and specific contaminant determinations). Industry-equivalent analytical standards from other organizations (ASTM, ISO) for sulfide/mercaptan analysis and caustic testing may be used in parallel depending on laboratory accreditation and regulatory requirements. See UOP listings for related method numbers in the same family.

Keywords

UOP 209-00; caustic analysis; spent caustic; alkalinity; potentiometric titration; sulfide; mercaptide; refinery process control; petrochemical laboratory methods.

FAQ

Q: What is this standard?

A: UOP 209-00 is a UOP laboratory method titled "Alkalinity, Sulfide and Mercaptide Analyses of Used Refinery Caustic Solutions" that specifies procedures to quantify alkalinity components and sulfur species in spent refinery caustic streams.

Q: What does it cover?

A: It covers two main parts — a potentiometric titration procedure to determine strong base, weak base (spent caustic) and total alkalinity (Part A), and analytical procedures to determine sulfur present as sodium sulfide and sodium mercaptide (Part B). It also includes an appendix with a simple double-indicator test for plant control.

Q: Who typically uses it?

A: Refinery laboratory personnel, process engineers, technical service teams, environmental labs and consultants who need quantitative data on caustic strength and sulfur species for process control, regeneration planning, disposal decisions, and troubleshooting.

Q: Is it current or superseded?

A: The document was issued in 2000 as UOP 209-00. Users should verify with UOP/Honeywell or their standards repository for any revisions, amendments, or superseding documents before relying on the method for compliance or critical control decisions.

Q: Is it part of a series?

A: Yes — it is part of the UOP family of test methods and process-chemistry procedures that cover a broad set of refinery analytical needs; related UOP method numbers appear in UOP listings and catalogs. Users commonly consult adjacent UOP methods for sampling, related titrations, and sulfur analyses.

Q: What are the key keywords?

A: caustic, spent caustic, alkalinity, potentiometric titration, sulfide, mercaptide, UOP, refinery analysis, process control.