Moisture analysis covers a variety of methods for measuring high levels of moisture, as well as trace amounts, in solids, liquids, or gases. There are many applications where trace moisture measurements are indispensable for manufacturing and for process quality assurance. Trace moisture in solids must be controlled for plastics, pharmaceuticals and heat treatment processes. Measurement applications in gases and liquids include, for example, drying processes, hydrocarbon processing, pure gases in the semiconductor industry, natural gas pipeline transport, the conditioning of food and other products. Written by experts with over 20 years of experience in the field, this one-stop guide covers all aspects of these measurements, including both the theory and a wealth of practical know-how. As such, it includes guidelines on installation, on the realization of standards for absolute and relative humidity, verification and traceability measurements, equipment calibration methods and the latest research developments. Backed by numerous case studies, this practical book serves the needs of those working in the industry tasked with performing or developing new techniques and processes for moisture and humidity measurement. As a result, the scientist or engineer has all the information required for accurate, reliable, economically viable and efficient moisture measurement.
Frequently asked questions
Yes, you can cancel anytime from the Subscription tab in your account settings on the Perlego website. Your subscription will stay active until the end of your current billing period. Learn how to cancel your subscription.
No, books cannot be downloaded as external files, such as PDFs, for use outside of Perlego. However, you can download books within the Perlego app for offline reading on mobile or tablet. Learn more here.
Perlego offers two plans: Essential and Complete
Essential is ideal for learners and professionals who enjoy exploring a wide range of subjects. Access the Essential Library with 800,000+ trusted titles and best-sellers across business, personal growth, and the humanities. Includes unlimited reading time and Standard Read Aloud voice.
Complete: Perfect for advanced learners and researchers needing full, unrestricted access. Unlock 1.4M+ books across hundreds of subjects, including academic and specialized titles. The Complete Plan also includes advanced features like Premium Read Aloud and Research Assistant.
Both plans are available with monthly, semester, or annual billing cycles.
We are an online textbook subscription service, where you can get access to an entire online library for less than the price of a single book per month. With over 1 million books across 1000+ topics, we’ve got you covered! Learn more here.
Look out for the read-aloud symbol on your next book to see if you can listen to it. The read-aloud tool reads text aloud for you, highlighting the text as it is being read. You can pause it, speed it up and slow it down. Learn more here.
Yes! You can use the Perlego app on both iOS or Android devices to read anytime, anywhere — even offline. Perfect for commutes or when you’re on the go. Please note we cannot support devices running on iOS 13 and Android 7 or earlier. Learn more about using the app.
Yes, you can access Industrial Moisture and Humidity Measurement by Roland Wernecke,Jan Wernecke in PDF and/or ePUB format, as well as other popular books in Physical Sciences & Industrial & Technical Chemistry. We have over one million books available in our catalogue for you to explore.
Water plays a key role in the formation and evolution of our planet and the life it supports. Water is present, in different aggregate states, throughout all parts of the Earth. In solid and liquid forms, water covers approximately 71% of the Earth's surface, while the large amount of gaseous, liquid, and solid water in the atmosphere governs both the global climate and the local weather. Global climatic balance and heat transfer are determined mainly by the large oceanic circulations of warm and cold water. Water has a high degree of transparency for visible light, one of the key factors that enabled the formation and evolution of life in the primeval oceans. The atmospheric layer of water vapor reflects heat emitted from the surface of the Earth and thus prevents the freezing of the planet. Liquid water forms the landscapes on continents, and its presence or absence determines the degree of biological activity and suitability for agriculture.
Every form of life on Earth requires water vapor in the respiratory air. Water is an essential component of each organism, and needs to be present in sufficient amounts at all times. Humans, for example, may survive without the intake of proteins, carbohydrates, and fiber for several weeks. Without water, however, survival is possible for only a few days. Humans require a daily amount of 2–3 l of water in order to maintain biological functions. Water has thus always been a central element in human consciousness and culture. In the ancient philosophies, for example, water is one of the four basic elements, and it is a symbol of purity and life in every religion.
Apart from its immediate nutritional function, humans make use of the different properties of water in many ways, for example,
for the generation of energy,
for the transportation of people and goods,
as a building material,
in industrial manufacturing processes,
for relaxing and recreation,
for the removal of waste,
as a cleaning agent, and
for the interim or final storage of many different materials.
1.2 Physical and Chemical Properties of Water
1.2.1 The Water Molecule
Water is a molecule consisting of two hydrogen atoms and one oxygen atom (Figure 1.1).
Figure 1.1 Binding angles in a water molecule.
The difference in electronegativity between oxygen and hydrogen, and the arrangement of atomic orbitals, results in an angle of 104.5° and thus the formation of an electric dipole. The negative charge of the molecular dipole is located at the free pair of valence electrons of oxygen, while the hydrogen ions form the positively charged pole. Different symmetric and asymmetric oscillation modes (Figure 1.2) can be excited and result in a variation of the dipole moment. The dipole character of water molecules is the reason for the formation of the strong intermolecular hydrogen bonds that cause clustering (Figure 1.3).
Figure 1.2 Vibration states of a water molecule.
Figure 1.3 Clustering of water molecules.
This results in a density that is significantly lower than that of chemically similar substances. The diameter of H2O molecules of 0.28 nm also differs from that of other components of air, such as
H2: 0.23–0.29 nm,
N2: 0.32–0.36 nm,
O2: 0.29–0.35 nm, and
CO2: 0.33 nm,
which makes the physical and chemical properties of water so unique. More than 40 anomalies of water, in terms of chemical, thermodynamic, electrical, or optical properties, to name but a few, have been observed in various experiments. Details can be found in the specialist literature.
1.2.2 Physical Properties
In the terrestrial atmosphere, water can be present in the solid, liquid, and gaseous states. All three phases are colorless and possess a high optical transparency in the visible and ultraviolet range. Infrared and microwave radiation, in contrast, is absorbed by water molecules due to the positions of the molecular energy orbitals. Water molecules are electrically neutral, but possess a dipole moment due to the inhomogeneous charge distribution.
The formation of clusters during freezing is the reason for the anomalous density change of water, compared to other molecules with similar structure. Due to clustering, water expands in volume during the phase transition from liquid to solid, which is associated with a reduction in density (Figure 1.4). This process continues as temperatures further decrease, as long as crystallization occurs. The crystal structure of water molecules in ice is a monocrystalline hexagonal lattice. Water has the highest density (e.g., smallest volume) at a temperature of around T ≈ 4 °C. A further increase in temperature results in a decrease in density, similar to any other liquid. This anomaly of density has direct implications on the landscape, and on natural processes: Lakes freeze from top to bottom, which allows fish to survive during winter. Water that penetrates into rock crevices and freezes during the night can cause significant frost wedging due to the volume expansion.
Figure 1.4 Density of water as a function of pressure.
A further anomaly of water is the temperature at which melting and freezing occurs. According to the chemical properties of compounds of hydrogen and other elements from group VI of the periodic table, the phase transition temperatures should be as shown in Figure 1.5.
Figure 1.5 Melting and boiling temperatures of hydrogen compounds in the oxygen group of the periodic table and the expected values for H2O.
The reason for this significant deviation is the strong hydrogen bonds between the molecules, which need to be overcome by using an increased amount of energy. As a consequence, the melting and evaporation temperatures of water at standard pressure are shifted to Tmelt = 0 °C and Tevapo = 100 °C, respectively. The strong hydrogen bonds also cause a strong surface tension at interfaces, which results in a high viscosity and a good wetting behavior on polarized surfaces.
Water possesses a high heat capacity, which dampens the low temperature change upon heating or cooling. Thus, the transition between the aggregate states is associated with a significant release or absorption of thermal energy.
1.2.3 Chemical Properties
Water is formed during the combustion or, more precisely, the oxidation of hydrogen according to
(1.1)
The oxidation is an exothermic process, where hydrogen is oxidized and oxygen is reduced. Water can be used as a solvent for a wide range of chemicals, because
it is soluble in many substances and forms free ions by dissociation,
it can be easily absorbed due to the low molar mass of the molecule,
the dipole of the molecules allows for the formation of stable bonds, and
the hydrogen bonds cause an interlinking with other polar molecules.
Salts, bases, and acids can be dissolved and diluted in water and are used for many chemical reaction processes. Dissolved oxygen is an important factor for life and biological activity. In the atmosphere, the ratio of oxygen to nitrogen is roughly 1 : 4. This ratio is 1 : 1.8 in water, that is, a much higher oxygen content, which is essential for the respiration processes of underwater life forms.
Metals are only corroded by liquid water and in environments with a relative humidity of U > 70%rh. Dissociation of water molecules yields unbound hydroxide ions, OH−, which are highly reactive. In the atmosphere, OH− ions react with many substances and pollutants and thus act as a cleaning agent. An example of this process is the natural decomposition of ozone by a reaction with water according to
(1.2)
Man-made atmospheric substances, for example, industrial sulfur compounds, are also, to a certain extent, decomposed and bound by water. This generates condensation nuclei, which causes cloud formation. The particles are then washed out of the atmosphere by precipitation, and into the ground. Investigations into the distribution of thes...
Table of contents
Cover
Related Titles
Title Page
Copyright
Preface
Chapter 1: Water – Substance of Life
Chapter 2: Thermodynamic Terms and Definitions
Chapter 3: Water in Solid, Liquid, and Gaseous Materials
Chapter 4: Moisture and Humidity Measurement Methods in Solid, Liquid, and Gaseous Substances
Chapter 5: Selection of a Measurement Method
Chapter 6: Reliability and Traceability of Measurements
Chapter 7: Moisture Measurement in Meteorology, Agriculture, and the Environment
Chapter 8: Applications in the Food and Beverage Industry
Chapter 9: Moisture and Humidity Measurement in Industrial Plants
Chapter 10: Applications in the Chemical, Pharmaceutical, and Plastics Industries
Chapter 11: Applications in the Manufacture and Processing of Paper and Textiles
Chapter 12: Moisture Measurement in the Building Industry
Chapter 13: Laboratory-Based Moisture Measurement
Chapter 14: Moisture and Humidity Measurement in Space
