Process Objectives

Feeds Products from Hydrotreating Products from Hydrocracking 

Atmospheric residue Lube base stock, low-sulfur fuel oil, RFCC feed Naphtha, middle distillates, FCC feed 

Vacuum residue RFCC feed Naphtha, middle distillates, RFCC feed 

FCC light cycle oil Blend stocks for diesel, fuel oil Naphtha 

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Feed characteri2ation, particularly for nondesalination appHcatioas, should be the first and foremost objective in the design of a reverse osmosis plant. This involves the determination of the type and concentration of the main solutes and foulants in the stream, temperature, pH, osmotic pressure, etc. Once the feed has been characteri2ed, a reaHstic process objective can be defined. In most cases, some level of pretreatment is needed to reduce the number and concentration of foulants present in the feed stream. Pretreatment necessitates the design of processes other than the RO module, thus the overaH process design should use the minimum pretreatment necessary to meet the process objective. Once the pretreatment steps have been determined and the final feed stream defined, the RO module can be selected. 

Prediction of reverse osmosis performance is usefiil to the design of RO processes. Simulation of RO processes can be separated iato two categories. The first is the predictioa of membrane module performance. The second is the simulation of a network of RO processes, ie, flow sheet simulations, which can be used to determine the optimum placement of RO modules to obtain the overaH process objective. 

Given the first type of simulation, it is advantageous to be able to design a system of RO modules that can achieve the process objective at a minimal cost. A model has been iategrated iato a process simulation program to predict the stream matrix for a reverse osmosis process (132). In the area of waste minimization, the proper placement of RO modules is essential for achieving minimum waste at a minimum cost. Excellent details on how to create an optimal network of RO modules is available (96). 

Process objective Material treated and process used References... 

Relationship between Fluid Motion and Process Performance Several phenomena which can be used to promote various processing objectives occur during fluid motion in a vessel. 

Process Objective UF is used for three principle objectives. First, to fractionate, to pass selectively one component through the membrane with the solvent. Second, to concentrate, to pass the solvent. These two, while different, are related and it is common to purify and concentrate a component siiTuiltaneously. The third objective, quite different, is to produce a solvent stream as a product. An example is the operation of an ultrafilter for producing low-cost permeate. An important apphcation of UF is in the automotive industiy where UF is used to remove water and microsolutes from huge electrophoretic paint tanks for use in rinsing excess paint (dragout) from... 

Suspended solids are often the process objective that requires a specific degree of uniformity. Five guides to better liquid/solid mixing are ... 

Similarly, different unit operations are available to accomplish the same processing objective. For example, a filter, a centrifuge, or a decanter could be used to separate a solid from a liquid. Crystallization or distillation could also be used for purification. 

All process objectives including cost effectiveness, yield enhancement, energy conservation, and environmental acceptability. 

Definition of process objectives Generation of separation core structure Selection of separation sequence and unit operations Addition of further units to the process structure Selection of crystallizer type... 

The process objectives defined earlier must relate to the process routes. A process route essentially consists of several sequential steps with the ultimate aim of achieving the process objective. There are one or more of basic objectives, namely, separation, production of a compound intermediate, metal reduction, and metal refining. With a given starting source material the four basic objectives can be pursued singly or in combination to arrive at the ultimate aim. For example, if the ultimate aim is to prepare a concentrate for the market then it is only the separation that is required for reaching to the product. If, on the other hand, purified metal production is the ultimate aim then possibly all the four objectives have to be fulfilled. 

The major raw materials used at present for the production of alumina are bauxites, which are found in the following mineral forms gibbsite (Al(OH)3), boehmite (AlO OH), and diaspore (AlO OH). The major impurities are the oxides of iron, silicon, and titanium, and organic compounds, all of which must be removed before alumina is suitable for aluminum production. The process objectives are, therefore, separation of impurities and compound production in the present case. Bauxite is first dried to facilitate grinding, destroy organic matter, and oxidize the associated ferrous minerals to the ferric state. The temperature of drying is not allowed to exceed 150 °C, because at higher temperature a part of the combined water is expelled and the solubility is affected adversely. 

The aim of this section is to provide a generic step by step methodology for the design of a final purification process for a non-salt form API using crystallization. The process objective is to consistently manufacture API of the desired purity and polymorphic form, within the constraints of a typical batch production facility. A brief outline of the analytical techniques that may be required is presented in section 4.6. 

Industrial boilers are employed over a wide range of applications, from large power-generating units with sophisticated control systems, which maximize efficiency, to small low-pressure units for space or process heating, which emphasize simpficity and low capital cost. Although their usual primary function is to provide energy in the form of steam, in some applications steam generation is incidental to a process objective, e.g., a chemical recovery unit in the paper industry. 

Wastewater effluents discharged to pubhcly owned treatment facilities are sometimes treated by physical or chemical systems to remove pollutants potentially hazardous to the POTW or which may be treated inadequately in the POTW. Such treatment methods are numerous, but they generally fall into one of three broad categories in accordance with their process objectives. These include pH control, removal of dissolved materials, and separation of phases. 

To ensure the successful design of a reverse osmosis process, several factors should be considered. These considerations encompass the feed solution, the membrane module, and the use of other processes in the pre- and post-treatment processes. A thorough knowledge of the feed stream and its components is essential to the prevention of membrane damage and product impurities. Once the feed stream is characterized and the process objective is defined, design can be initiated. 

Environmental process objectives would include the following ... 

Irrespective of the approach taken to scale-up, the scaling of unit operations and manufacturing processes requires a thorough appreciation of the principles of similarity. Process similarity is achieved between two processes when they accomplish the same process objectives by the same mechanisms and produce the same product to the required specifications. Johnstone and Thring (56) stress the importance of four types of similarity in effective process translation (1) geometric similarity (2) mechanical (static, kinematic, and dynamic) similarity (3) thermal similarity and (4)... 

The heliocentric pattern of asteroid types, with thermally processed objects closer to the Sun (as inferred from spectra), persists despite subsequent dynamical stirring of asteroid orbits and ejection of bodies from the main belt. Differentiated objects appear to have formed earlier than chondritic bodies, and dynamical modeling suggests they may have accreted... 

To illustrate the potential of the use of organic solvents to increase (among other process objectives) the enantioselective performance of the enzyme, three cases of interest will be discussed in some detail. 

Heightened empathy with external processes, objects, and people. 

The reduction in viscosity of distillation residua tends to reach a limiting value with conversion, although the total product viscosity can continue to decrease. The minimum viscosity of the unconverted residue can lie outside the range of allowable conversion if sediment begins to form. When shipment of the visbreaker product by pipeline is the process objective, addition of a diluent such as gas condensate can be used to achieve a further reduction in viscosity. 

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