ASTM D8393-21 PDF

Overview

ASTM D8393-21: Standard Guide for Determination of Pore Volume of Powdered Catalysts and Catalyst Carriers by Water Adsorption sets out guidance for measuring the pore volume of powdered catalysts and catalyst carriers using water adsorption. Accurate determination of mesopore and macropore volume is a significant quality attribute for materials used primarily in fluid catalytic cracking (FCC) processes and other catalyst applications.

This standard is intended for use by professionals in materials specification, manufacturing control, and research and development where the evaluation and quality assessment of catalytic materials is critical. The guide ensures consistent and reliable measurement practices across laboratories and industries.

Key Topics

• Scope of Measurement:

  • Specifies use for fine catalysts and catalyst carriers, including FCC catalysts, additives, and spray-dried products.
  • Suitable for powders predominantly ranging from 20 to 150 µm equivalent spherical diameter and average particle size from 60 to 100 µm.
  • Capable of measuring pore volume in the range of 0.25 mL/g to 0.46 mL/g.

• Principle of Method:

  • Pore volume is determined by titration with deionized water, leveraging capillary action for adsorption in mesopores (2-50 nm) and macropores (>50 nm).
  • Water should not chemically react with the material during analysis.

• Procedure and Apparatus:

  • Employs a burette for controlled water addition, analytical balance for precise weighing, muffle furnace, conical flask, thermostatic water bath, and other standard laboratory glassware and tools.
  • Post-sample preparation, water is gradually titrated and absorbed until saturation, with endpoint determined by changes in sample consistency and adhesion.

• Calculation and Reporting:

  • Pore volume is calculated using the ratio of the total water absorbed to the mass of the sample.
  • Results should be expressed in SI units.

• Safety and Compliance:

  • Adhering to health, safety, and environmental regulations is the user's responsibility.
  • Developed per international standardization principles, including those set out by the WTO TBT Committee.

Applications

• Catalyst Characterization:

  • Measurement of pore volume is essential for optimizing FCC catalysts used in petroleum refining, especially for cracking heavy oils. The presence and size of mesopores and macropores significantly influence catalyst reactivity and selectivity.

• Quality Control:

  • This method allows manufacturers and users to verify catalyst specifications, control batch-to-batch variation, and ensure product conformity for customers.

• Research and Development:

  • Provides reliable data for development of new catalyst formulations, enhancement of manufacturing processes, and comparison with alternative measurement techniques such as mercury intrusion porosimetry (see ASTM D4284).

• Materials Specification:

  • Used as a standard reference in procurement and supply chain documentation for powdered catalysts and related products.

Related Standards

• ASTM D4284 - Test Method for Determining Pore Volume Distribution of Catalysts and Catalyst Carriers by Mercury Intrusion Porosimetry.

  • Noted correlation between water adsorption and mercury intrusion techniques.

• ASTM D1193 - Specification for Reagent Water.

• ASTM D4464 - Test Method for Particle Size Distribution of Catalytic Materials by Laser Light Scattering.

• ASTM E105 - Practice for Probability Sampling of Materials.

• ASTM E177 - Practice for Use of the Terms Precision and Bias in ASTM Test Methods.

• ASTM E456 - Terminology Relating to Quality and Statistics.

• ASTM E691 - Practice for Conducting an Interlaboratory Study to Determine the Precision of a Test Method.

By following ASTM D8393-21, stakeholders in catalyst production and use can ensure that pore volume measurement is consistent, reliable, and aligned with international best practices, supporting optimal catalyst performance and regulatory compliance.

Keywords: ASTM D8393-21, pore volume, powdered catalysts, catalyst carriers, water adsorption, FCC catalyst, mesopore, macropore, catalyst characterization, quality control, standard guide.