Concise Handbook of Fluorocarbon Gases

Applications in Refrigeration and Other Industries

Sina Ebnesajjad

• Publisher: Wiley-Scrivener
• Year: 2021
• Print ISBN:
  9781119322979
• Edition: 1
• eBook ISBN:
  9781119323259
• Topic: Technology & Engineering
• Subtopic: Chemical & Biochemical Engineering
• Index: Technology & Engineering

This book describes fluorocarbons gases' preparation process, properties, applications and their evolution over time. The impact of fluorocarbons on the ozone layer and global and the development to mitigate those effects have been specially emphasized.

The first major industrial fluorinated compound was developed in the 1920's, to replace ammonia and sulfur dioxide refrigerants, at the General Motors Frigidaire Division by Thomas Midgley, Jr. and Albert Leon Henne. They developed a family of fluorocarbons trademarked Freon® for auto air conditioning units revolutionizing the auto industry. Other applications were developed over time including fire extinguishers, propellants, blowing agents, cleaners, anesthesia, artificial blood and others impacting every facet of life.

In spite of being in broad global use for nearly a century, fluorocarbon gases have gone through great evolution during the last few decades. In the 1980s it was discovered chlorofluorocarbon (CFC) gases are harmful to the ozone layer, mainly because of their chlorine content. Chlorine was released in the upper atmosphere when chlorofluorocarbon molecules were broken down by the high energy cosmic radiation. CFCs were progressively banned following the Montreal Protocol of 1987.

CFCs were replaced by fluorinated gases containing either less chlorine (hydrofluoro-chlorocarbons, or HCFCs), which are much less damaging (about 90% less) to the ozone layer or with fluorinated gases containing no chlorine, i.e. hydrofluorocarbons or HFCs. HFC have no impact on the ozone layer but impact global warming detrimentally. HFCs are usable without need for changes to the existing refrigeration or air conditioning installations. More recently hydrofluoroolefins (HFOs), which have little or no negative impact on global warming, have been developed to replace or reduce the use of HFCs. HFOs are used as single compounds or in blends. Research and development continues to develop and replace the HCFCs and HFCs completely with environmentally friendly products.

Concise Handbook of Fluorocarbon Gases presents a reference and text for the commercial fluorocarbon gases which have great many application in a wide range of industries such as refrigeration and air conditioning, as well as consumer products.

1
Introduction

Dictionaries define fluorocarbons as any of various chemically inert compounds containing mainly carbon and fluorine. They are used to produce refrigerants, fire extinguishing and foaming agents, aerosol propellants, polymers, nonstick coatings and lubricants. In the industry parlance the term fluorochemicals is often used instead of fluorocarbon. Rather fluorocarbons usually refer to small molecule fluorinated gases and liquids. The magic in these compounds of all sizes is in the carbon fluorine bond (C-F). It has a dissociation energy of 536 kJ/mol ranking as the single strongest carbon bond [1–4]. The replacement of C-H bond in hydrocarbons with C-F is the single most important factor giving rise to the unique properties of fluorocarbons.

1.1 Terminology

In this book the terms fluorochemicals and fluorocarbons refer to all aliphatic organic compounds containing fluorine and carbon, i.e. fluorinated chemicals. Aliphatic is defined as straight chain, branched chain, or cyclic, saturated, as in the paraffin; or unsaturated, as in the olefins and alkynes. Cyclic fluorocarbons are not discussed in this book because their limited commercial applications.

More specifically the term fluorocarbon refers to small molecule of fluorinated alkane and olefin compounds. Fluorinated polymers and fluoropolymers are used to refer to, mostly, olefinic macromolecules of fluorinated thermoplastics and elastomers. Partially fluorinated refers to a material that contains residual C-H or other bonds. Perfluorinated refers to the absence of hydrogen in a chemical due to complete fluorine substitution. Other atoms such as oxygen, sulfur and nitrogen may be present in the structure of the perfluorinated chemicals, often in small quantities.

Commercial is the guiding beacon for the selection of the contents of the present book. The focus is on fluorochemicals produced and consumed in commercial applications. An important aspect of the commercial consumption of fluorocarbons is their impact on the ozone layer as a result of emissions of those chemicals. The issue came to surface when chlorofluorocarbons were discovered to deplete atmospheric ozone layer. That discovery has resulted in decades of development of replacement compounds and elimination of all ozone depleting fluorocarbons.

The three major groups of commercial products consumed in large quantities are listed in Table 1.1. Of the major fluorinated organic products, only fluorocarbons have small molecules and interact with the ozone layer. Some of the precursors of fluoropolymers and fluoroelastomers impact the ozone layer thus must be contained while being converted to polymers.

Table 1.1 Examples of commercial fluorochemicals.

Product	Size of molecule	Example of compound	Example of application
Fluorocarbons	Small	HFC-134a (1,1,1,2-tetrafluoroethane)	Refrigerant, Propellant for aerosols, Blowing agent for foams
Thermoplastic Fluoropolymers (TPF) and Fluoroelastomers (FE)	Large macromolecules	Polyvinylidene fluoride (TPF), copolymer of vinylidene fluoride/tetrafluoroethylene	Tubes, pump bodies (TPF), seals and gaskets (FE)
Fluorinated Coating - Dispersion (D), powder (P)	Large macromolecules	Polytetrafluoroethylene coatings, Tetrafluoroethylene/perfluoroalkylvinylether copolymer powder	Interior surface of oil pipelines (D), Corrosion resistant (P)

The terms ozone depletion refer to the destruction of atmospheric ozone by the decomposition products of certain gases. Ozone by its action filters out low wavelength ultraviolet light waves known as “UV B” which are hazardous to humans, and some plants and wildlife. Destruction of the atmospheric ozone reduces its filtration action thus allowing an increase in the UV B light waves that reach the earth surface. The First generation of fluorocarbon gases were discovered to be strong causes of ozone depletion. A great deal of global regulatory changes, research, publication, development and replacement have taken place since the 1980s. These issues are discussed in detail in the rest of this book.

Most public and technical discussions about ozone layer and depletion are not quantitative. Nevertheless, atmospheric ozone has been measured to allow factual analysis of changes in the ozone layer. The Dobson Unit (DU) is the unit of measure for total ozone ranging from 100 to 500. If one were to take all the ozone in a column of air stretching from the surface of the earth to space (Figure 1.1) and bring all that ozone to 0°C and pressure of one atmosphere, the column would be about 0.3 centimeters thick. Thus, the total ozone would be 0.3 atm-cm. To make the units easier to work with, the “Dobson Unit” is defined to be 0.001 atm-cm, 0.3 atm-cm would be 300 DU [5].

Incidentally, Dobson Unit is named after Gordon Miller Bourne Dobson (1889-1976) who was a British physicist and meteorologist. Professor Dobson was an ingenious experimentalist who devoted much of his life to the observation and study of atmospheric ozone. He made measurements at a number of locations in Europe to study the relation between ozone distribution and synoptic meteorological variables. The results of Dobson’s studies turned out to be of great importance. They lead to an understanding of the structure and circulation of the stratosphere including the ozone layer [7].

Figure 1.1 Depiction of Dobson Unit for ozone quantitative measurement [6].

1.2 Production and Consumption Statistics of Fluorocarbons

Statistics on the production and consumption of fluorocarbons illustrate the continued growth of those products. A major study published by the US Government in February 2020 sheds light on the global development, trade and consumption of fluorocarbon gases and their alternatives. This study is the result of collaboration of Department of Energy’s National Renewable Energy Laboratory and Oak Ridge National Laboratory [8] Some of the highlights of this study are described in the next Section (1.2.1).

1.2.1 Refrigerants: Market Trends and Supply Chain Assessment

This section has been adopted with some modifications from a Department of energy study published in May 2020 [8]. The conclusions of the reported study are listed in this section. The term refrigerants has a broad meaning in this report because most of the refrigeration gases are also used in non-refrigeration applications.

The global refrigerants market is large and is projected to grow rapidly as developing countries in warmer areas of the globe continue to grow, become more affluent, and consume more and more air conditioning, refrigeration, foam, and aerosol products and services. Innovations in the global refrigerants market is often led by major U.S. companies; however, the markets for their products are global. Understanding this global market landscape is a critical component for maintaining U.S. leadership in innovation and manufacturing in a strategically important industry.

Key Findings from the National Renewable Energy Laboratory (NREL)/Oak Ridge National Laboratory (ORNL) include:

• Refrig...

Table of contents

• Cover
• Table of Contents
• Title Page
• Copyright
• Preface
• 1 Introduction
• 2 Classification and Description of Commercial Fluorinated Compounds
• 3 Fluorine Sources and Basic Fluorocarbon Reactions
• 4 Applications of Fluorocarbon Gases and Liquids
• 5 Refrigeration Cycle and Refrigerant Selection: How Refrigerant Gases Work?
• 6 Preparation of Fluorocarbons
• 7 Properties of Fluorocarbons
• 8 Environmental, Safety, Health and Sustainability
• 9 Fluorocarbon Blends
• 10 Substitute Fluorocarbons and Other Compounds
• 11 Future Directions of Fluorocarbons
• Appendix I
• Appendix II: OzonAction Kigali Fact Sheet 6
• Appendix III: PARIS AGREEMENT
• Index
• End User License Agreement