Large-scale industrial design

The effect of increasing column diameter is to increase the tendency for circulation, and hence to increase the axial mixing (62,63). However, extremely few measurements of axial mixing at the industrial scale are available, so large-scale contactor design must still rely quite heavily on empirical experience with the particular type of equipment. 

Most large-scale industrial methacrylate processes are designed to produce methyl methacrylate or methacryhc acid. In some instances, simple alkyl alcohols, eg, ethanol, butanol, and isobutyl alcohol, maybe substituted for methanol to yield the higher alkyl methacrylates. In practice, these higher alkyl methacrylates are usually prepared from methacryhc acid by direct esterification or transesterification of methyl methacrylate with the desired alcohol. 

This chapter discusses adsorption fundamentals relating to the design and operation of large-scale industrial separations using zeolite molecular sieves. 

Thermal decompositions (pyrolyses) and catalysed reactions in the vapour phase are widely used large-scale industrial techniques. These vapour phase reactions often lead to more economic conversions than the smaller batchwise laboratory methods, because relatively inexpensive catalyst preparations (compared to the often expensive reagents required in laboratory procedures) may be used, and because the technique lends itself to automated continuous production. In undergraduate laboratory courses the technique has not achieved widespread use. The discussion below of the various apparatus designs, to meet a range of experimental conditions, may be regarded as an introduction to this topic. 

This new style of synthetic catalysis will of course not replace all normal synthetic methods. For many purposes, the standard methods and rules - e.g. aldehydes are more easily reduced than are ketones - will continue to dominate organic synthesis. However, when we require a synthetic transformation that is not accessible to normal procedures, as in the functionalization of unactivated carbons remote from functional groups, artificial enzymes can play a role. They must compete with natural enzymes, and with designed enzyme mutants, but for practical large-scale industrial synthesis there can be advantages with catalysts that are more rugged than proteins. 

Ole Jentoft Olsen (DSS Danish Separation Systems) presented a large-scale industrial example on using ultrafiltration for the production of antibiotics. Within 15 hr, a volume of 100 metric tons of biomass was processed. The design of membrane module, operational conditions, and the overall plant were presented, along with detailed cost considerations for this process. 

The modelling of super critical water oxidation (SCWO), up to now not been used in large scale industrial applications, is important for design of pilot plants and, later, industrial plants. The applied programme to model the continuous flow in a reactor is called CAST (Computer Aided Simulation of Turbulent Flows [8]) and is based on the method of the finite volume. That means that the balance equations were integrated over the surfaces of each control volume. 

This chapter considers large-scale industrial tree plantations, as well as small- and medium-scale plantations for timber and land rehabilitation. Aspects that influence plantation sustainability are emphasized, and suggestions are given regarding plantation design and management. 

In contrast to packed catalyst beds, however, countercurrent flow of gas and liquid is in principle possible in internally finned monoliths at realistic fluid velocities that are of interest for large-scale industrial applications. The main limitation to countercurrent flow at high velocities is at the outlet of a channel, rather than in the channel itself. With a suitable design of the outlet geometry, however, this problem can be alleviated so that countercurrent operation becomes possible in the velocity range of interest. 

The need to govern heat balances properly in membrane reactors will certainly become a major task if large-scale industrial units are ever to be put into operation. Whether the performed reaction is endothermic (dehydrogenation) or exothermic (oxidation), innovative means to supply or remove heat from large-scale membrane reactor modules will have to be designed. The isothermicity assumption valid for several lab-scale membrane reactors will not hold anymore, and much more complex modeling will certainly have to be developed. 

Continuous reactor configurations are generally favored for very large-scale industrial processes. If the process is required to produce only 2 million kg/year or less, the economics of construction will generally dictate that a batch process be used [19]. If, however, 9 million kg/year of product or more is required, there is a strong incentive to apply some type of continuous reactor configuration in the design of the production unit. 

Assuming that all modem large scale industrial fermentation plants sterilize media through a continuous sterilizer, the heat transfer design of the fermenter is only concerned with the removal of heat caused by the mechanical agitator (if there is one) and the heat of fermentation. These data can be obtained while running a full scale fermenter. The steps are as follows ... 

Membrane science and technology is interdisciplinary, involving polymer chemists to develop new membrane structures physical chemists and mathematicians to describe the transport properties of different membranes using mathematical models to predict their separation characteristics and chemical engineers to design separation processes for large scale industrial utilization. The most important element in a membrane process, however, is the membrane itself. To... 

Unfortunately, in many cases the availability of the actual material that needs to be processed in a new installation is limited at the time of plant design. The testing of similar materials from different sources, even if they are chemically identical and seem to be physically comparable, is not recommended because traces of impurities and minuscule changes of surface structure, for example, can decisively change many or all aspects of a material s agglomerative behavior. Therefore, a common desire is to use small laboratory, often desk top equipment in an effort to develop the sizing and parameters of a large scale industrial plant. 

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