ASTM D7795-15(2022)e1 PDF
Standard Test Method for Acidity in Ethanol and Ethanol Blends by Titration
Standard Test Method for Acidity in Ethanol and Ethanol Blends by Titration
- Статус документа:
- Действующий
- Формат:
- Электронный (PDF)
- Количество страниц:
- 7
- Дата публикации:
- 1 апреля 2022 г.
- Издание:
- D7795
- ICS:
- 75.160.20
SIGNIFICANCE AND USE 5.1 This test method measures acidity in ethanol or ethanol blends quantitatively. Denatured fuel ethanol may contain additives such as corrosion inhibitors and detergents as well as contaminants from manufacturing that can affect the acidity of finished ethanol fuel. Very dilute aqueous solutions of low molecular mass organic acids, such as acetic acid, are highly corrosive to many metals. It is important to keep such acids at a very low level. 5.2 Acceptable levels of acidity in ethanol or ethanol blends can vary with different specifications but in general it is below 200 mg/kg (ppm). Knowledge of the acidity can be required to establish whether the product quality meets specification. SCOPE 1.1 This test method covers the determination of acidity as acetic acid (see Specification D4806) in commonly available grades of denatured ethanol, and ethanol blends with gasoline ranging from E95 to E30. This test method is used for determining low levels of acidity, below 200 mg/kg (ppm mass), with the exclusion of carbon dioxide. 1.1.1 Procedure A—Developed specifically for measurement of acidity by potentiometric titration. This is the referee method. 1.1.2 Procedure B—Developed specifically for measurement of acidity by color end point titration. 1.2 The ethanol and ethanol blends may be analyzed directly by this test method without any sample preparation. 1.3 Review the current and appropriate Material Safety Data Sheets (MSDS) for detailed information concerning toxicity, first aid procedures, and safety precautions and proper personal protective equipments. 1.4 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard. 1.5 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use. Some specific hazards statements are given in Section 7 on Hazards. 1.6 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
Abstract
Overview
ASTM D7795-15(2022)e1: Standard Test Method for Acidity in Ethanol and Ethanol Blends by Titration is an internationally recognized standard developed by ASTM International. This test method quantitatively measures the acidity levels in denatured ethanol and ethanol-gasoline blends (ranging from E30 to E95). Monitoring acidity is critical to maintaining the quality and safety of ethanol fuel, as even dilute solutions of low molecular mass organic acids like acetic acid can be highly corrosive to metals and cause significant degradation of storage and handling equipment.
ASTM D7795 provides two main procedures for acidity determination:
- Procedure A: Potentiometric titration (referee method).
- Procedure B: Color end point titration.
The method enables rapid, accurate evaluation of acidity, ensuring that ethanol fuels meet accepted quality specifications, typically keeping acidity below 200 mg/kg (ppm).
Key Topics
- Test Scope: Covers acidity measurements (as acetic acid) in denatured ethanol and ethanol-gasoline blends without the need for complex pre-treatment or sample preparation.
- Measurement Methods:
- Potentiometric titration: Utilizes a specialized pH electrode for precise endpoint detection.
- Color end point titration: Employs phenolphthalein as an indicator for manual titrations.
- Sample Handling: Direct analysis of samples; steps to minimize contamination by carbon dioxide.
- Significance: Controls corrosive acid content from contaminants, additives, or byproducts, protecting storage systems and engines from premature wear or failure.
- Precision & Quality Control: Stipulates regular calibration and statistical quality assurance procedures to maintain reliability and consistency of results.
- Safety Considerations: Emphasizes compliance with safety data sheets (SDS), proper use of personal protective equipment, safe handling of flammable and corrosive substances, and adherence to environmental and waste regulations.
Applications
- Fuel Quality Assurance: Ensures that ethanol fuels and blends meet regulatory and industry specifications for acidity, supporting fuel performance and durability.
- Corrosion Prevention: Detects and helps control corrosive acids that can damage transportation and storage infrastructure, fuel injection systems, and engine components.
- Manufacturing & Supply Chain: Supports producers, blenders, and distributors of ethanol fuel in quality assurance, troubleshooting, and product certification.
- Regulatory Compliance: Helps demonstrate adherence to national and international fuel standards and technical barriers to trade requirements, facilitating market access.
This method is particularly valuable for:
- Ethanol fuel producers and blenders
- Fuel quality laboratories
- Regulatory agencies overseeing fuel safety
- Engine and vehicle manufacturers requiring data on fuel compatibility
Related Standards
ASTM D7795 references and aligns with several key industry standards to ensure consistent and accurate acidity measurement. Related standards include:
- ASTM D4806: Specification for Denatured Fuel Ethanol for Blending with Gasolines
- ASTM D1193: Specification for Reagent Water
- ASTM D6299: Practice for Statistical Quality Assurance and Control Charting Techniques
- ASTM D6708: Practice for Statistical Assessment and Improvement Between Test Methods
- ASTM D4175: Terminology Relating to Petroleum Products, Liquid Fuels, and Lubricants
- ASTM D770: Specification for Isopropyl Alcohol
- Practice E200: Preparation, Standardization, and Storage of Standard and Reagent Solutions for Chemical Analysis
The standard was developed in accordance with internationally recognized principles for standards development, aligning with the World Trade Organization (WTO) Technical Barriers to Trade (TBT) Committee requirements.
Keywords: ASTM D7795, acidity in ethanol, ethanol blends, titration method, fuel quality testing, automotive fuel standards, acetic acid in ethanol, potentiometric titration, quality control in fuel analysis, denatured ethanol compliance
Технические детали
- Технический комитет
- D02 - Petroleum Products, Liquid Fuels, and Lubricants
- SKU
- ASTM D7795-15(2022)e1
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