High Pressure Process Technology: Fundamentals and Applications

A. Bertucco, G. Vetter

• Publisher: Elsevier Science
• Year: 2001
• eBook ISBN:
  9780080533940
• Topic: Physical Sciences
• Subtopic: Industrial & Technical Chemistry

Clear evidence of increasing demands in the processing industry prompted the editors and authors to publish a new book about High Pressure Process Technology: Fundamentals and Applications.This book presents the latest knowledge regarding the high pressure processing aspects combined with that about the modeling, the design and the operation of safe and reliable high pressure plants and equipment. This treatment and selection of the subjects is stimulating and unique. Consisting of nine chapters, each subdivided into several sections, the book addresses the high pressure aspects, providing well selected correlated information connected with a comprehensive overview together with a large number of references. The main body of the first eight chapters refers to subjects like high pressure in general, the thermodynamics and kinetics of the fluids involved, the design of high pressure equipment, the modeling and design of reactors, separation and fractionation units, the safety aspects, the control and economics.In the extended last chapter, examples of promising high pressure applications are explained, such as chemical and enzymatic reactions in supercritical solvents, hydrogenation under supercritical conditions, supercritical water oxidation, polymerization with metallocene catalysts, supercritical extraction, fractionation and precipitation, supercritical pharma processing, ultra-high pressure sterilization and supercritical dry-cleaning.

Chapter 1

Introduction

G. Vetter, Department of Process Machinery and Equipment; University Erlangen-Nuremberg, Cauerstr. 4, D-91058 Erlangen, Germany

The definition of high pressure, examples in nature, and the early historical roots of high pressure technology are explained. The motivation of using high pressure today is based on chemical, physico-chemical, physico-bio-chemical, physico-hydrodynamical and physico-hydraulic effects. A survey of today high pressure technology is given demonstrating the large range of applications and comprising many branches and processes of production. A number of examples like the production of polyethylene and fatty alcohols, the decaffeination of coffee beans, the homogenisation of foodstuffs, the water-jet cutting and cleaning, the polymer processing, the ultra-high pressure treatment for the aseptic processing as well as the hydrostatic pressure applications for pressing hydroforming and autofrettage are outlined shortly.

1.1 High Pressure definitions and examples in nature

Within man’s living environment on this planet the pressure ranges from a low vacuum – around 0,25 bar on top of the highest mountain – up to a high pressure of around 1000 bar – on the deepest ocean floor – both exceeding the physiological limits of human beings more or less drastically.

In general living beings on the planet earth are behaving very differently with respect to their compatibility towards pressurized environment. Some species of microbes are able to suffer several thousand bar and there are sea mammals such as whales which dive down to a depth of 1000 m – equal to a pressure difference of 100 bar – within short time intervals, a procedure which would kill human beings immediately.

In the interior of our planet millions of bar are to be expected. On the other hand we are able to develop hundreds of thousands of bar during the technical synthesis of diamonds. Fundamental physical research about the behaviour of matter has now been extended beyond the level of one million bar.

It is a characteristic feature of technical processes with high pressure conditions to exhibit absolutely artificial environments, far beyond those existing in nature. High pressure machinery and containment are required to maintain these, “artificial conditions”. With regards to the term “High Pressure” we should not become confused by linguistic terms such as high blood pressure, high-pressure areas in weather forecasts, high political or moral psychological pressure, pressure exerted from above and below, etc.

The “high pressure” this book is focused on represents the physical pressure defined as the force load per the unit of area (Newton/m²: N/m²; 10⁵ N/m² = 1 bar) exhibiting the “normal” atmospheric pressure of our natural environment (ambient or barometric pressure).

1.2 Early historical roots of high pressure technology

The well-known first double-piston pumps of Ktesebios during Archimedes’ time, water supply pipes in the ancient world together with Roman pump developments, as well as Agricola’s (see: Twelve Books of Mining 1596) wooden “high pressure pumps” for the drainage of mines (100 m depth =10 bar pressure) during the Middle Ages show early applications of high pressure.

James Watt’s steam engine (around 1785) working with several bar steam pressure only, innovated the world’s energy supply and induced an industrial revolution. This steam engine represented one of earliest high pressure processes for power generation.

Starting in the Middle Ages, from the development of firearms and guns based on explosives emerged the problem of designing safe containments (gun barrels) against the high detonation pressure (today, several thousand bar).

As an early milestone of high pressure chemical processing should be mentioned the synthesis of ammonia by Haber and Bosch (Nobel prize 1918). This typical high pressure (300 − 700 bar) process already shows all the characteristics of the similar ones of today. It should be regarded as the initiation of the very successful development of the high pressure chemistry during the last century, including the still up-to-date super-pressure polymerisation of ethylene (3000 bar). Since the mid-20^th century diamonds have been synthesized by transforming graphite into diamond at pressures above 120000 bar (3000°C) with a solid-state process and special apparatus.

1.3 High pressure technology today – motivations for using high pressure

High pressure is a proven tool for a number of industrial processes and promising ones in the future. The following effects of high pressure should be distinguished.

The chemical effect of high pressure is to stimulate the selectivity and the rate of reaction together with better product properties and quality as well as improved economy. This is based on better physico-chemical and thermodynamic reaction conditions such as density, activation volume, chemical equilibria, concentration and phase situation. Many successful reactions are basically enhanced by catalysis.

The physico-chemical effect of high pressure, especially in the supercritical state, to enhance the solubility and phase conditions of the components involved. Supercritical hydrogenation, or enzymatic syntheses are offer new steps with high pressure. Supercritical water oxidation at high pressure represents an efficient method for the decontamination of wastes.

From the application of high pressure liquid or supercritical carbon dioxide as a solvent have emerged a number of promising or successful production processes such as supercritical extraction, fractionation, dyeing, cleaning, degreasing and micronisation (rapid expansion, crystallization, anti-solvent recrystallization). New material properties can be achieved by foam expansion, aerogel drying, polymer processing, impregnation and cell-cracking with high pressure supercritical CO₂ [1, 2].

The physico-bio-chemical effect of the high pressure treatment predominantly of foodstuffs and cosmetics, is now emerging. For the sterilization (pasteurisation, pascalisation) high pressure offers an alternative to high temperature. Furthermore, treatment with static high pressure gives a promising improvement of certain organic natural products by advantageous swelling, gelation, coagulation and auto-oxidation effects in combination with fats or proteins. This selection of high pressure effects actually is however only under increasing research however only and successful practical applications have not been achieved yet [3].

The physico-hydrodynamical effect of high pressure is based on the conversion of the potential (pressure) into kinetic energy (high speed fluid jetting: 100 − 1000 m/s). The main applications are the homogenisation of fluid mixtures by expanding them through very narrow clearances, water-jet cutting and water-jet cleaning, and the generation of sprays with fine droplets for efficient combustion or spray-drying of fine particles.

The phy...

Table of contents

• Cover image
• Title page
• Table of Contents
• Industrial Chemistry Library
• Copyright page
• Preface
• Contents
• List of Contributors
• About the Editors
• Chapter 1: Introduction
• Chapter 2: Thermodynamic Properties at High Pressure
• Chapter 3: Kinetic Properties at High Pressure
• Chapter 4: Design and Construction of High-Pressure Equipment for Research and Production
• Chapter 5: Industrial Reaction Units
• Chapter 6: Separation Operations and Equipment
• Chapter 7: Safety and Control in High Pressure Plant Design and Operation
• Chapter 8: Economics of High Pressure Processes
• Chapter 9: Applications
• 9.2: Enzymatic reactions
• 9.3: Hydrogenation under supercritical single-phase conditions
• 9.4: Supercritical Water Oxidation (SCWO). Application to industrial wastewater treatment
• 9.5: High-pressure polymerization with metallocene catalysts
• 9.6: Supercritical Fluid Extraction and Fractionation from Solid Materials
• 9.7: High pressure polymer processing
• 9.8: Precipitation of solids with dense gases
• 9.9: Pharmaceutical processing with supercritical fluids
• 9.10: Treating micro-organisms with high pressure
• 9.11: Dry-cleaning with liquid carbon dioxide
• Subject Index