ASTM E947-22 PDF

Overview

ASTM E947-22 is the Standard Specification for Sampling Single-Phase Geothermal Liquid or Steam for Purposes of Chemical Analysis. Published by ASTM International, this standard details essential requirements and equipment guidelines for collecting uncontaminated and representative samples from single-phase geothermal liquid or steam flows, including geopressured liquids. The standard is intended to support accurate chemical analysis by ensuring that the collection process preserves the integrity of the geothermal sample throughout extraction, cooling, and storage.

This specification emphasizes the use of dedicated sample probes, appropriate materials, robust safety practices, and precise control over sampling conditions to prevent contamination, bias, or sample losses. It also addresses the need for clean and well-designed sampling apparatus for reliable analysis in geothermal energy exploration, monitoring, and research.

Key Topics

• Sample Probe Design and Placement: Probes are inserted directly into the central flow of piping to ensure samples are truly representative of the single-phase fluid, not affected by wall deposits or stagnant areas.

• Sampling Line Construction: Short, sturdy lines made of corrosion-resistant materials are recommended to retain sample quality and avoid structural failures.

• Valves and Fittings: Full-port ball or gate valves are required to give probes unrestricted access to fluid flow. Specialized valves and fittings must prevent sample contamination and allow access for temperature and pressure measurements.

• Sample Cooling: The specification outlines continuous tubing through the cooling coil to prevent contamination or dilution, with proper regulation of cooling rates for both liquid and steam.

• Container Requirements: Sample containers and closures for both liquids and gases must not leach or adsorb analytes, thereby ensuring analytical accuracy.

• Cleaning and Maintenance: All sampling equipment must be kept clean, rinsed with distilled water, and free from lubricants or residues that could influence chemical results.

• Safety Practices: The standard addresses the importance of safe probe insertion and removal, as well as leak-free operation during high-pressure geothermal sampling.

Applications

ASTM E947-22 is widely applicable in the geothermal energy sector for operations such as:

• Resource assessment: Collecting baseline data for geothermal reservoir evaluation and exploration.
• Plant monitoring: Regular sampling for operational control and chemical monitoring in geothermal power plants.
• Environmental compliance: Ensuring samples collected are suitable for regulatory reporting and environmental impact analyses.
• Research and development: Supporting laboratory and field studies on the chemical composition of geothermal fluids for improved exploitation methods.

Using the correct sampling techniques defined by this standard helps eliminate errors due to contamination, phase separation, or chemical changes during sampling, making it indispensable for those working with geothermal steam or liquids.

Related Standards

Professionals using ASTM E947-22 should also be aware of the following ASTM standards and guides:

• ASTM E1675 - Practice for Sampling Two-Phase Geothermal Fluid for Purposes of Chemical Analysis (useful for cases involving two-phase fluid flows).
• ASTM D1192 (Withdrawn) - Former guide for equipment used in sampling water and steam in closed conduits.

These documents, alongside ASTM E947-22, provide a comprehensive framework for geothermal sampling, ensuring sample integrity whether the target is single-phase steam, liquid, or more complex multi-phase conditions.

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