Industrial problems

In the previous chapters we have shown how to solve many types of problems that occur in Chemical and Biological Engineering through mathematical modeling, standard numerical methods, and MATLAB. 

We have introduced many practical software based numerical procedures to solve physico-chemical models for simulation and design purposes. Therefore, we hope that our readers now feel comfortable and ready to handle more complex industrial problems from the modeling stage through the numerical solution and model validation stages on her/his own. 

Industrial problems are usually more complicated than the earlier problems in this book. But their solutions generally require the same steps, tools and procedures. Therefore, an engineer needs to learn how to handle these problems in both a direct and an integrated way. A typical industrial problem might involve solving one system of differential equations and then solving an algebraic equation (or another DE) at each point of the solution profile. 

We will start by introducing a relatively simple integrated example from industry to illustrate what this means. This example will be followed by a number of industrial problems in separate sections. In this chapter we will explain and model each industrial problem and we will develop strategies for a numerical solution. However, explicit solutions and MATLAB codes for these problems will be left to the reader throughout this chapter as exercises. We hope that we have given the necessary tools in the previous chapters to enable our readers to solve these industrial problems. Some results for the industrial problems of this chapter will be included so that the reader can check his or her own results. However, we emphasize that actual industrial problems take much effort, perseverance and labor for anyone who models and solves them. 

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In this paper, the performanees of laser-ultrasound are estimated in order to identify lacks of weld penetration. The laser-ultrasonic technique is applied to cylindrical metallic strucmres (few mm thick) in a single-sided control. The results obtained for different materials (gold-nickel alloy and tantalum) are presented by B-sean views for which the control configuration is discussed with regard to the thermal effects at the laser impact. This testing is performed for different lacks of weld penetration (up to 0.5 mm for a thickness of 2 mm) even in the presence of the weld bead, which corresponds to an actual industrial problem. 

A low temperature of approach for the network reduces utihties but raises heat-transfer area requirements. Research has shown that for most of the pubhshed problems, utility costs are normally more important than annualized capital costs. For this reason, AI is chosen eady in the network design as part of the first tier of the solution. The temperature of approach, AI, for the network is not necessarily the same as the minimum temperature of approach, AT that should be used for individual exchangers. This difference is significant for industrial problems in which multiple shells may be necessary to exchange the heat requited for a given match (5). The economic choice for AT depends on whether the process environment is heater- or refrigeration-dependent and on the shape of the composite curves, ie, whether approximately parallel or severely pinched. In cmde-oil units, the range of AI is usually 10—20°C. By definition, AT A AT. The best relative value of these temperature differences depends on the particular problem under study. 

This is because the effect of the dispersed soHd, rather than the dispersing medium, is usually more significant. However, the latter should not be ignored. Many industrial problems involving unacceptably high viscosities in dispersed systems are solved by substituting solvents of lower viscosity. 

Localized corrosion, which occurs when the anodic sites remain stationary, is a more serious industrial problem. Forms of localized corrosion include pitting, selective leaching (eg, dezincification), galvanic corrosion, crevice or underdeposit corrosion, intergranular corrosion, stress corrosion cracking, and microbiologicaHy influenced corrosion. Another form of corrosion, which caimot be accurately categorized as either uniform or localized, is erosion corrosion. 

Many sources contain scattered information concerning cooling water system corrosion and defects, and many literature studies describe corrosion processes and mechanisms from a predominantly theoretical viewpoint. Until now, however, no source discusses cooling water system corrosion with emphasis on identification and elimination of specific problems. Much of the information in this book is unique every significant form of attack is thoroughly detailed. Color photos illustrate each failure mechanism, and case histories further describe industrial problems. 

After the preliminary tests are made on a promising catalyst and some insight gained on the process, it is time to do a kinetic study and model development. The method of a kinetic study can be best explained on an actual industrial problem. Because more can be learned from a failure than from a success, the oxidation of propylene to acrolein is an instructive attempt at process development. (Besides, to get permission to publish a success is more difficult than to solve the problem itself) Some details of the development work follow in narrative form to make the story short and to avoid embarrassing anyone. 

Barnbrook, G., The concrete slab-a base for resin flooring, paper presented at the Symposium on Resin for Industrial Problem Areas. Flooring and Anti-Corrosion Application, organized by the Federation of Resin Formulators and Applicators Ltd, London, November (1980). 

For gas-phase reactions, the molar density is more useful than the mass density. Determining the equation of state for a nonideal gas mixture can be a difficult problem in thermod5mamics. For illustrative purposes and for a great many industrial problems, the ideal gas law is sufficient. Here it is given in a form suitable for flow reactors ... 

The basic problems involved in emulsion and foam chemistry are discussed with emphasis on how to solve them and how to correlate the information thus obtained for future use and interpretation. A blending of theoretical and practical knowledge has to be used, and examples are given to illustrate the methods of solving the industrial problems involved. 

On innovating to imitate nature The wonders of nature inspire imitations that can yield environmentally sensible solutions to industrial problems. 

Applications On a comparative basis, HTGC is a relatively new tool and extremely valuable for the analyses of extracted polymer additives, as shown by industrial problem solving. For satisfactory analysis of in-polymer additives by HTGC two specific conditions are to be met. The instrument should be equipped with a cool on-column injection port to better preserve some of the additives and/or their by-products that may be thermally labile. The instrument must also have electronic pressure control so that some of the very high-boiling components, such as Irganox 1010, are... 

Major applications of modern TLC comprise various sample types biomedical, pharmaceutical, forensic, clinical, biological, environmental and industrial (product uniformity, impurity determination, surfactants, synthetic dyes) the technique is also frequently used in food science (some 10% of published papers) [446], Although polymer/additive analysis takes up a small share, it is apparent from deformulation schemes presented in Chapter 2 that (HP)TLC plays an appreciable role in industrial problem solving even though this is not reflected in a flood of scientific papers. TLC is not only useful for polymer additive extracts but in particular for direct separations based on dissolutions. 

Kenion et al. [225] used LD FTMS for direct analysis of a discoloured adhesive. MALDI-FTICR-MS is a direct way of examining molecular weight distributions. FTMS is not yet widely being used for industrial problem solving, despite long-lasting expectations. Instead, FTICR-MS is the method of... 

To master one scientific topic after another, Haber skipped dinners and studied until 2 a.m. With overflowing enthusiasm, he ignored the conventional boundaries between abstract and practical science between chemistry, physics, and engineering and between mechanics, technicians, and scientists. He solved industrial problems posed by the iron plates used to print banknotes and by Karlsruhe s corroded water and gas mains, and then made fundamental discoveries in electrochemistry. Conversely, he used the abstract theory of gas reactions in flames to explain to manufacturers why some reactions continue spontaneously while others stop. Soon he had contributed basic scientific insights to almost every area of physical chemistry. 

The identification and structural characterization of biological materials, obtained for example from plants, was traditionally carried out via the classical sequence involving extraction, separation, isolation and characterization, a sequence which requires large amounts of substance and a great deal of time. Industrial problems, for example the search for small amounts of contaminants in industrial products or in waste water, also require intensive analytical studies. 

From the case studies reported in this chapter, it has been shown that a systematic approach to failure analysis and contamination issues can be applied to a broad and diverse range of industrial problems. The use of techniques such as SEM, NMR, and FTIR can often provide information relevant to the cause of... 

New enzymes to address industrial problems are searched among a collection of more than 25,000 classified microorganisms. These microorganisms cover a broad range of habitats, from garden soil to extreme conditions (volcanoes, polar ice, and deep-sea environments). This biodiversity multiplies the number of possible derivable enzymes nature is the basis for all its products. 

Formation of acetic acid from methanol and carbonylation of alcohols still are important industrial problems, but milder conditions are needed. Other metals, such as rhodium, have proved to be more suitable. 

There are a number of major industrial problems in the operation of the steam reforming of methane. These include the formation of carbon on the surface of the catalyst, the sulphidation of the catalyst by the H2S impurity in commercial natural gas, and the decline of catalytic activity due to Ostwald ripening of the supported catalyst particles by migration of catalyst atoms from the smaller to the larger particles, as the temperature is increased. A consideration of the thermodynamics of the principal reaction alone would suggest that the reaction shifts more favourably to the completion of the reaction as the temperature is increased. 

Developed frameworks are applied to the specific industry problem to monthly plan a global chemical commodity value chain by volumes and values. Sub-objectives are to elaborate characteristics and planning requirements for a global commodity value chain in the chemical industry and to develop, implement and evaluate the respective model. Research question 2 is directed to a real industry case study demonstrating the real existence of formulated requirements, showing the applicability of the developed model in reality and evaluating the model using industry data. 

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