Technical Chemistry

The Chemistry is concerned with the transfer of chemical reactions and processes in technical processes and the optimization of existing processes and procedures under economic and environmental considerations.
Chemical production

The main areas of research and teaching lie on the catalyst – and process development , the mechanical and thermal unit operations, the customer process and chemical reaction engineering .

History
Sulfuric acid plant by the lead chamber process in the second half of the 19th Century [1]

The beginnings of industrial chemistry can be made ​​in the seventeenth century through the works of Johann Rudolph Glauber about the production of acids and salts found. Glauber presented concentrated hydrochloric acid and nitric acid ago and discovered in 1625 was named after him Glauber’s salt . [2] One of the highlights of industrial chemistry in the eighteenth century was the development of the lead chamber process by John Roebuck . [3] As early as 1746 in England, the first lead chamber process started. The process was developed more than once, particularly by Joseph Louis Gay-Lussac , the 1827 introduced the so called Gay-Lussac tower for recovery of the nitrogen oxides, and in 1859 by John Glover introduced step Stickoxidreoxidation by atmospheric oxygen in the Glover tower.

Early knowledge of chemical engineering was summarized in textbooks. Thus defined Johann Friedrich Gmelin in 1795 the Technical Chemistry in his work Handbook of Industrial Chemistry as follows:

“Chemistry is that part of applied chemistry, which the principles of chemical plants, factories, arts and artisans, and their application vortheilhafte teaches on this.”

– Handbook of Industrial Chemistry, Volume 1, by Johann Friedrich Gmelin, 1795 [4]

The history of industrial chemistry in the true sense but to the development of the chemical industry as a sector bound. They learned with the development of aniline dyes by August Wilhelm Hofmann , especially in Germany a renaissance. From 1859 were in Germany within a few years many Farbenfabriken founded as Boehringer Mannheim , [5] the Bayer sites [6] , Hoechst , [7] the Baden Aniline and Soda Factory (BASF), [8] Agfa , [ 9] Schering [10] and Boehringer Ingelheim . [11]

To bridge the gap between the demands of the industry and the graduates of university education, the end of the nineteenth century were at the initiative of the German Chemical Society, and Carl Duisberg founded Institute for Technical Chemistry increased. [12]
Scheme of the Haber-Bosch process

A milestone in technical chemistry at the beginning of the 20th Century was the synthesis of ammonia by Haber and Bosch represents Fritz Haber in 1898 as an associate professor of chemical engineering at the University of Karlsruhe appointed, in 1904, it dealt with the production of ammonia from its elements. The development of the Haber-Bosch process was in many respects, a challenge to the chemistry and process technology, it represents had reactors are being developed that pressures up to 300 bar and temperatures up to 500 ° C was maintained, and there were catalysts developed a economic yield of ammonia allowed.

In the twenties and thirties of the twentieth century, coal and were acetylene chemistry, the dominant themes of industrial chemistry. [13]

The availability of cheap oil after 1950 and thus also of ethylene resulted in an unprecedented expansion of industrial chemical production and thus more recent developments in industrial chemistry. A milestone of this period, the development of low-pressure process for producing polyethylene by Karl Ziegler represents.

Basics

Chemical reactions can not be easily transferred to the industrial-scale production. The Chemistry is therefore concerned with the question of how many tons of the same product can be produced in a factory while minimizing manufacturing cost. This is done empirically , or by a mathematical optimization, on the basis of a model description of the reaction and the reactor. Nearly every chemical production can be divided into three steps:

\ Begin {prepare \ to \ response \ to \} treatment

First are the precursors prepared in the second step is the actual response instead. Finally in the last step, the reaction mixture is treated. With the preparation and processing is employed to chemical engineering , with the reaction on an industrial scale, the chemical reaction engineering . For the necessary calculations must transport, heat and time budgets are created. Often dimensionless numbers (are Euler number , Reynolds number , Nusselt number , Damköhler number ) used to the scale-up easier.

The Chemical Technology enables efficient production of basic , intermediate and finished products. Between 1970 and 1980 through improvements of chemical processes, the energy requirements for chemical reactions in the same production volume decreased by approximately 40%. [15]
Chemical Process Expertise
Reactors

An important aspect of industrial chemistry is the understanding of the material composite of industrial organic and inorganic chemistry. From the organic raw materials, oil, coal and renewable resources will initially create the basic chemicals. Hence a variety of intermediate and end products produced.

The Chemical Process customer continues to investigate the process and reaction procedures of the major industrial chemical products.

Starting from the raw oil , natural gas , coal , and in the last few years in renewable raw materials are first basic chemicals such as olefins and aromatics produced.

These are then on intermediates as alcohols , phenols , aldehydes , ketones , carboxylic acids or amines for further processing.

The end products of the chemical industry, such as polymers , detergents , pesticides , pharmaceuticals and dyes are made ​​from the basic and intermediate products.

The raw materials of industrial inorganic chemistry include air , sulfur , sodium chloride , coke and water , which make up about a few intermediate steps, such as ammonia and chlorine make the end products produced as acids, alkalis, fertilizers, glass, pigments, catalysts and materials.

The task of industrial chemistry is from the existing potential pathways to determine, subject to availability of resources and taking into account the energy consumption the most economical method each way.

Chemical processes are distinguished by the type of chemical reaction carried out, for example, chlorination , hydration , nitration , oxidation , polymerization, or sulfonation . The power supply can be effected in various ways, such as thermally, electrochemically or photochemically .

If both types of reaction possible, in addition to technical conditions may also affect the market economy, the decision on whether a process is carried out continuously or discontinuously as a batch process. Continuous systems are usually produced in large quantities for a product, while a batch process often allows for greater flexibility in the product variation, but at the cost of the quantity produced.

Additional features for classification, the number of chemical processes are carried out step (single / multi-stage), the heat of reaction (endo-/exotherm) and the nature of the catalysis (homogeneous / heterogeneous / biocatalysis).
Catalysis

: → Main article catalysis

Catalysis research occupies a special place within the chemical engineering, since about 80% of all chemical products during their production through a catalytic process.

In the production of basic and intermediate products plays the heterogeneous catalysis by far the largest role in the production of intermediate and end products, the importance of homogeneous and biocatalytic processes.

Based on the results of basic research [16] is increasingly trying to provide the catalyst and process development in a knowledge-oriented basis.
Basic Operations

The necessary addition to physical processes in the chemical reactions of a process called mechanical and thermal unit operations. Basic operations are the basic steps in the implementation of a procedure.

These are used in the preparation of starting materials, for example by grinding, mixing the reactants and the promotion and processing of products by separation processes.
Mechanical unit operations
Flotation

The important mechanical basic operations include the method of association substance, promoting and shaping, the separation process as well as the crushing method for solids.

As a method for the substance including the association will emulsify the kneading, the mixing , the pelletization , the presses , the stirring , the suspension , the mixing and spraying used. One of the most important ways to promote the pump .

Mechanical separation processes are used, inter alia, in order to separate solids from liquids and gases or liquids from gases. Known separation processes for the deposition, the decantation , the electrodeposition , the filtration , the flotation , the sedimentation , the views , the screening , the sorting and the centrifugation .

Crushing methods are usually the setting of certain grain size distributions, or for increasing the surface, to run faster as a chemical reaction. Commonly used methods here are the break , the grinding , the grinding, tearing and fragmentation .
Thermal Unit Operations
McCabe-Thiele diagram

By thermal unit operations can be separated substances or unite. According to the type of phases following thermal unit operations can be distinguished:

Gas-liquid: rectification , absorption
Liquid-liquid: liquid-liquid extraction
Solid-Liquid: crystallization
Gas-Solid: adsorption

The by far most frequently used method for separation is the rectification stage as the distillation can be carried out in several stages in continuous or discontinuous layer process or else. Rectification were once common on the graphical McCabe-Thiele method designed.
Chemical Reaction Engineering

→ Main article: Chemical Reaction Engineering

The chemical reaction engineering is concerned with the design of chemical reactors under reaction conditions such as temperature and pressure, the mass and energy balance, and the macro-kinetics of a reaction with the aim to minimize the capital and operating costs of a reactor at optimum throughput.

Examples of the basic types of chemical reactors are of the tubular reactor , the stirred tank and the continuous stirred tank . Important characteristic of these types of reactors, the residence time . Simplified mathematical models of these reactor types as ideal reactors designated.
Recent Developments

The recent developments in chemical engineering are characterized by increasing pressure on the economy and ecology of the processes and the dwindling supplies of key raw materials, especially petroleum. An overview of the main trends, the trend report of Chemistry, of the German Chemical Society is published. [17] Examples of recent developments include the use of biomass as a chemical feedstock, the microreactor technology and the use of novel solvents.

Sustainable chemistry [18] : it is mainly investigated the use of biomass as a chemical feedstock. Research focuses on the selection and preparation of renewable resources, the subsequent chemistry and interfaces for biotechnology .
Microreactor technology [19] : The microreactor technology components used to carry out chemical reactions, the particle size in the millimeter to centimeter range. The aim of the research is the development of micro-reactors and the study of chemical reactions in micro-reaction conditions, because usually there are no problems with mixing, diffusion or heat transfer.
Novel solvent: in performing homogeneous catalytic process, the recovery of the catalyst and the separation of the products from the solvent is often critical to the economics of a process. Attempts will be reactions in supercritical solvents , ionic liquids or perform in water. Wherein the ionic liquids are salts that are liquid at room temperature or slightly above. By choosing suitable cation – / Anionpaare the properties of these fluids can be specifically adjusted within a wide range. They are due to their ionic nature hardly volatile and have properties that are very different from conventional organic solvents. [20] water as a solvent often offers the advantage that the resulting organic product of a homogeneous catalytic reaction does not mix with water, and therefore a simple separation allowed. Also the use of hyperbranched polymer [21] [22] is examined.

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