Lubricant Blending and Quality Assurance

R. David Whitby

• Publisher: CRC Press
• Year: 2018
• eBook ISBN: 9780429882579
• Topic: Physical Sciences
• Subtopic: Industrial & Technical Chemistry

Many people, including those involved in the manufacturing, marketing and selling of lubricants, believe that blending lubricants is simply a matter of putting one or more base oils and several additives into a tank of some kind and stirring them around to mix them. Blending lubricants that meet customers' demands requires much more than this. The correct ingredients of the right quality need to be used in precisely controlled quantities. The ingredients need to be tested prior to blending and the finished products need to be tested following blending. The ingredients need to be stored and mixed under carefully controlled conditions. The finished lubricants need to be stored and packaged carefully and then delivered to customers correctly.

This book discusses all of these issues, describes the different types of equipment used to blend lubricants, provides guidance on how best to use this equipment, and offers tips and techniques to help to avoid problems. It focuses on liquid lubricants. Greases are not discussed, as their manufacture involves very different manufacturing procedures compared with those concerned with liquid lubricants.

The book starts with descriptions and discussion of the properties and characteristics of the main types of mineral and synthetic base oils, as well as the properties and characteristics of the main types of additives that are used in lubricant formulations. Criteria and methodologies used to design both new and upgraded blending plants are covered next. The types and operation of the equipment used in lubricant blending plants are described and discussed, together with a chapter on how to avoid problems before, during, and after blending. Testing and analysis of base oils, additives, and blended lubricants are covered in two separate chapters. Procedures for quality control and quality management in lubricant blending plants are also discussed in two separate chapters. Types of packages for lubricants are reviewed, together with methods for filling packages and methods for transporting lubricants in bulk. The storage of lubricants and supply chain management is also covered in depth.

1 Introduction

1.1 Purpose

Many people, including those involved in the manufacturing, marketing and selling of lubricants, believe that blending lubricants is simply a matter of putting one or more base oils and several additives into a tank of some kind and stirring them around to mix them.

Blending lubricants that meet customer’s demands requires much more than this. The correct ingredients of the right quality need to be used in precisely controlled quantities. The ingredients need to be tested prior to blending, and the finished products need to be tested following blending. The ingredients need to be stored and mixed under carefully controlled conditions. The finished lubricants need to be stored and packaged carefully and then delivered to customers correctly.

This book discusses all these issues, describes the different types of equipment used to blend lubricants, provides guidance on how best to use this equipment and offers tips and techniques to help avoid problems.

This book focuses on liquid lubricants. Greases are not be discussed, as their manufacture involves very different manufacturing procedures compared with those concerned with liquid lubricants.

1.2 Approach

In order to manufacture high-quality lubricants, high-quality ingredients, suitable equipment, correct procedures and methodologies, standardised testing, appropriate packaging, correct storage conditions, a well-trained workforce and excellent management are required. All these subjects are discussed in this book.

Consequently, we approach this task in a methodical way. We start by considering the numerous types of base oils and additives that are used to manufacture lubricants. The base oils used in lubricants are classified into two broad groups: mineral oils and synthetic oils. Within each group there are significant differences between different base oils. There is no single “universal” base oil that will be suitable for use in all lubricant applications. This book illustrates and discusses all the main types of base oils used in lubricants.

Many hundreds of additives are used in different types of lubricants. This book explains why additives are used, the main types of additives and their functions and the very variable physical and chemical properties of different classes of additives. The fundamental importance of these differences to the operation of a lubricant blending plant is explained.

We then look into how and what goes into formulating a lubricant (selecting which base oils and additives to use) and why this can be important in making a product easier or more difficult to blend. The methodology of formulating, developing and testing a new or improved lubricant is complicated and time-consuming. Lubricant formulation chemists and engineers do not just select a base oil or additive because it happens to be available or low cost. Selecting which base oil(s) and additives to use for a specific lubrication application requires a great deal of experience, skill, testing and refinement.

Having discussed the ingredients and recipes for lubricants, we then look at how and why blending plants are designed. Many factors and a huge amount of market, technical, logistical and process information must be gathered and evaluated as inputs into the design of an efficient and profitable lubricant blending plant. This book describes and discusses these factors and the information required. We then look at the options available for lubricant blending plant layouts, with their advantages and disadvantages. Finally, the elements of the design process are considered, as well as the use of computer-aided design programmes for producing the detailed design plans and construction drawings.

Chapter 7 focuses on the types of equipment used in a lubricant blending plant. The advantages of each type of equipment are considered and the relationships between the various facilities are discussed. We look at the operation of each type of equipment, so that lubricant blending plant managers, supervisors and operators can gain insights into the efficient and effective use of the facilities in their plant. The chapter also discusses systems for automating the processes used to blend lubricants.

As with any commercial or industrial activity, difficulties can occur with blending lubricants from time to time. People frequently refer to “unforeseen circumstances”. In the author’s opinion, many of these circumstances are entirely foreseeable. One of the key tricks to managing and operating a successful activity is to avoid problems before they occur. Chapter 8, on avoiding problems, considers a number of foreseeable situations that can occur in a lubricant blending plant and how to guard against them happening. We look at lists of do’s and don’ts to minimise risks before, during and after operations.

To start to consider product quality control, quality assurance and quality management, we look first at the testing and analysis of base oils and additives in blending plants. Manufacturing high-quality products requires high-quality raw materials, together with effective process management and control. This book describes the tests that a lubricant blending plant can use to evaluate the physical and chemical properties of the raw materials that will be used. It also provides guidance on the specifications that can be used for these base oils and additives, as well as the relationships that can be applied to the companies that supply these raw materials.

Following on, Chapter 9 looks at the testing and analysis of the lubricants that have been blended. Hundreds of different tests can be used to assess the properties and performances of lubricants. Many are used in the formulation and development of new or improved lubricants, and they are likely to be expensive and time-consuming. As a consequence, they are of little practical value in a lubricant blending plant. The tests used in a blending plant need to be quick and comparatively low cost, to enable products to be packaged and delivered to customers as soon as practical. Many of the tests used to evaluate the chemical or physical properties of base oils and additives are also applicable for blended lubricants. However, there are a number of tests that are only applicable to finished lubricants, so these are described. Blending plant managers, supervisors and operators need to know and understand what happens in a blending plant laboratory.

In order to deliver lubricants that meet customers’ requirements, the supply chain must be able to control the quality of the products it supplies. The first problem is to define what is meant by quality. The second problem is to establish methods for measuring it, and the third problem is to implement strategies and plans to control it. Chapter 11, on quality control, focuses on all three issues. It provides definitions and advice on methodologies for quality control and quality assurance. Quality management, a different subject, is the focus of Chapter 14. We look at controlling quality before, during and after blending. We also discuss external organisations that monitor the quality of lubricants in the market. At the end of the chapter, we present and discuss an established method to help the quality control and quality assurance processes, using a coding system for raw materials and lubricant formulations.

High-quality blended lubricants need to be packaged correctly into the various types of containers that will be used to deliver them to customers. Some containers are very large, while others are very small. This book describes the numerous types of packages used for lubricants, together with the advantages and disadvantages of some of them. Filling lubricants into these containers is also very important for the effective and efficient delivery of the products to users. Various methods used to fill lubricants into containers are presented and discussed. For many of the lubricants used by customers, the packaging forms an integral and important part of the marketing and branding of the products. This book discusses these aspects of lubricant packages. We also look at some aspects of the reuse or recycling of many of the packages for lubricants.

Storing lubricants correctly is just as important in a blending plant as it is in a customer’s premises. The facilities and methods of operating a lubricant blending plant warehouse are presented and discussed. This includes warehouse management systems and automated storage and retrieval systems and their advantages and disadvantages. Large volumes of lubricants tend to be stored outdoors, while smaller volumes of lubricants and products that are sensitive to oxidation, moisture, dust, dirt, heat or cold tend to be stored indoors. Aspects of the storage of base oils and additives are be presented and discussed.

Producing and delivering high-quality products does not just happen. The entire process has to be managed. The strategies and activities required to manage product quality effectively and efficiently have been developed and improved over many years. The culmination of these developments and improvements was the publication of the ISO 9000 series of standards. This book looks at the principles and methodologies of Total Quality Management, with a specific focus on ISO 9000, 9001 and 9004.

This book is intended for everyone involved in supplying high-quality lubricants to customers. It is important that everyone in the whole supply chain understands the importance of the roles that each of the participating groups plays. Without the skills, experience, communication and understanding of all the people involved in manufacturing, marketing and delivering lubricants to customers, the chances of providing consistently high-quality products efficiently and profitably all the time are not high.

This book aims to enable all the participants in a company’s supply chain for lubricants to achieve their goals.

2 Mineral Oil Base Oils: API Groups I, II and III

Properties and Characteristics

2.1 Introduction

Mineral base oils are classified into two broad types, paraffinic and naphthenic, depending on the types of crude oils from which they are derived. Naphthenic crude oils are characterised by the absence of wax or have very low levels of wax. They are largely cycloparaffinic and aromatic in composition; therefore, naphthenic lubricant fractions are generally liquid at low temperatures without any dewaxing. Conversely, paraffinic crude oils contain wax, consisting largely of n-paraffins, which have high melting points. Paraffinic crude oils also contain iso-paraffins and some cycloparaffins and aromatics. (An explanation of these types of compounds is given in Section 2.4.) Waxy paraffinic distillates have melting or pour points that are too high for winter use, so the n-paraffins have to be removed by dewaxing. After dewaxing, the paraffinic base oils may still solidify, but at higher temperatures than do naphthenic ones because their molecular structures have a more paraffinic “character”. Paraffinic base oils are preferred for most lubricant applications and constitute about 90% of the world’s supply.

2.2 Base Oil Nomenclature

Lubricant base oils have a number of acronyms that are used in the industry to describe them. American Petroleum Institute (API) Group I and Group II base oils (see Section 2.6 for an explanation of Groups I, II, III, IV and V) are first described by their viscosities, measured in Saybolt universal seconds (SUS) at 100°F. Typical nomenclatures are 70, 100, 150, 300, 500, 600 and 900, although different refineries manufacture and supply many other viscosity grades. The lower numbers refer to less viscous base oils, with the viscosities increasing as the numbers get bigger.

This nomenclature was developed in the United States at the beginning of the twentieth century, as one of the first attempts to categorise paraffinic base oils. The SUS unit was first proposed by George M. Saybolt, and the Saybolt universal viscometer was first standardised by the U.S. Department of Commerce in 1918.¹ The SUS viscosity of a liquid is the time taken for 60 ml of the liquid, held at a specific temperature (usually 100°F [37.78°C]), to flow through a calibrated tube. SUS viscosities can be converted to other measurements of kinematic viscosity (see Chapter 9).

These viscosity numbers are followed by either “SN”, in the case of API Group I base oils, or “N”, in the case of API Group II base oils. “SN” refers to “solvent neutral”. Group I base oils are generally manufactured using solvent refining processes (see Section 2.3), while Group II base oils are generally manufactured using hydroprocessing. In both cases, the “N” refers to “neutral”, in that the oils are neither acidic nor basic in character. Before the introduction of solvent refining processes, the vacuum distillate fractions of crude oil were treated with concentrated sulphuric acid to remove as...

Table of contents

• Cover
• Half-Title
• Title
• Copyright
• Contents
• dedication
• Preface
• Author
• Chapter 1 Introduction
• Chapter 2 Mineral Oil Base Oils: API Groups I, II and III: Properties and Characteristics
• Chapter 3 Synthetic Base Oils: API Groups IV and V: Properties and Characteristics
• Chapter 4 Lubricant Additives: Properties and Characteristics
• Chapter 5 Lubricant Formulation and Ease of Blending
• Chapter 6 Lubricant Blending Plant Design: Grassroots Plants and Upgrading Existing Plants
• Chapter 7 Lubricant Blending Plant Equipment and Facilities and Their Operation
• Chapter 8 Lubricant Blending Issues: Avoiding Problems
• Chapter 9 Testing and Analysis of Base Oils and Additives in Blending Plants
• Chapter 10 Testing and Analysis of Blended Lubricants
• Chapter 11 Lubricant Product Quality Control
• Chapter 12 Lubricant Packaging and Filling
• Chapter 13 Lubricant Storage
• Chapter 14 Product Quality Management
• Glossary
• Index