Approach to process design


Network analysis, or pinch technology, has become an increasingly powerhil approach to process design that includes most of the virtues of second-law analysis. For example, pinch technology can be broadened to include process revisions such as changing the temperature and pressure of distillation columns to fit into the natural cascade of high level heat dropping down to ambient (10). Other extensions of the concept include analysis of distillation column profiles, total site integration, and batch processing (11). The approach yields a quantitative estimate of readily achievable improvement. For example, in Figure 5, note the reduction in steam and cooling water obtained by driving the design to the pinch, AT.  [c.87]

Since its founding, CCPS has published many volumes in its Guidelines series and in smaller Concept texts. Although most CCPS books are written for engineers in plant design and operations and address scientific techniques and engineering practices, several guidelines cover the subject of chemical process safety management. Successful process safety programs are the products of committed and active participation of managers at all levels who apply a systematic approach to process safety as an integral part of operations management.  [c.226]

Important issues to support the development of capable and reliable products have also been discussed. These include a team approach to engineering design, the generation of an adequate number of design schemes from which to determine the most effective design solution, assessment of external supplier capability and the importance of the design review process in forming a traceable record of technical performance versus customer requirements. The vital role that quality philosophies, such as TQM, have on improving and driving the product development process has been emphasized.  [c.276]

Andersson, P. A. 1996 Process Approach to Robust Design in Early Engineering Design Phases. PhD Thesis Department of Machine Design, Lund Institute of Technology, Lund, Sweden.  [c.381]

Air Extraction from the Enclosure A textbook approach to enclosure design for a hot process would follow a procedure of determining the in-draft veloc-  [c.900]

You should determine the importance of various optimization concepts in design of composite structures. Actually, the structural design process Is optimization, i.e., you are always seeking the best design where best is measured in a variety of ways depending on the application. We must deal with many design variables such as plate thickness, stiffener spacing, etc. Thus, to believe that optimization concepts are the ideal approach to structural design is very tempting. It would be nice if we could say that mathematical optimization is a practical way for us to design a large structure right now, because that s what we would like very much to do. However, some practical limitations on optimization do exist that involve computer size, speed, and cost, as well as an ability to treat all the design variables.  [c.370]

The fundamental laminate problem is given the overall loading and a rough idea of the shape that we want, what is the optimum set of laminae orientations that constitute this laminate Here, we must get quantitative and outline a specific approach to laminate design. First, we do not even know how many laminae we need Our basic objective is that we want to carry a certain set of ioads. The design process is not simply finding a thickness as with a metal plate, it is finding a thickness and what goes into that thickness, namely the number and orientation  [c.433]

You should determine the importance of various optimization concepts in design of composite structures. Actually, the structural design process Is optimization, i.e., you are always seeking the best design where best is measured in a variety of ways depending on the application. We must deal with many design variables such as plate thickness, stiffener spacing, etc. Thus, to believe that optimization concepts are the ideal approach to structural design is very tempting. It would be nice if we could say that mathematical optimization is a practical way for us to design a large structure right now, because that s what we would like very much to do. However, some practical limitations on optimization do exist that involve computer size, speed, and cost, as well as an ability to treat all the design variables.  [c.370]

The fundamental laminate problem is given the overall loading and a rough idea of the shape that we want, what is the optimum set of laminae orientations that constitute this laminate Here, we must get quantitative and outline a specific approach to laminate design. First, we do not even know how many laminae we need Our basic objective is that we want to carry a certain set of ioads. The design process is not simply finding a thickness as with a metal plate, it is finding a thickness and what goes into that thickness, namely the number and orientation  [c.433]

BASIC Programs for Chemical Engineering Design, James H. Weber Catalyst Poisoning, L. Louis Hegedus and Robert W. McCabe Catalysis of Organic Reactions, edited by John R. Kosak Adsorption Technology A Step-by-Step Approach to Process Evaluation and Application, edited by Frank L. Slejko  [c.673]

To give some structure to the process design it is common to present information and ideas in the form of process flow schemes (PFS). These can take a number of forms and be prepared in various levels of detail. Atypical approach is to divide the process into a hierarchy differentiating the main process from both utility and safety processes.  [c.239]

Once the network has been synthesized, traditional design techniques are used to set stream flows through parallel units and analyze iadividual heat exchangers, heaters, and coolers. Optimization of these iadividual units is also considered at this poiat. The optimization of heat exchangers iavolves such things as baffle and tube sheet layout as well as pressure drop. This multiple tier approach to the problem is necessitated by the complexity of the design process which must span the gulf from conceptual network development to detailed mechanical rating of heat exchangers.  [c.518]

Two approaches are commonly used for pilot-plant design. The first uses conventional design techniques which mimic commercial process design. This usually provides for a safe and operable design as the design methodology is known and the effectiveness of the final results have been proven previously. This approach is not always feasible the proposed scale of the pilot-plant operation maybe completely outside the range of all commercial design techniques, the design suggested may not be economical on the scale envisioned or in the location proposed, or copying the commercial design may carry some inherent limitations that adversely impact operations at ranges or conditions which are of interest to the pilot plant but not to the commercial plant. The alternative approach is to use a design methodology oriented to the pilot plant using many conventional design techniques but trying to maximize the advantages of the pilot-plant operations with regard to scale, technique, and operation. Advantages include economic savings due to reduced equipment, constmction, and operating costs, economical and efficient ways around otherwise expensive problems, increased simplicity of operation resulting in reduced maintenance and operating staff, and improved process understanding through use of specialized equipment. The lack of pubUshed design information, however, raises the risk factor hence the quaUty of the final design is very dependent on the skill level and experience of the design engineer.  [c.41]

Towers, entrainment separators, thermowells, and mpture disks are fabricated of impervious graphite material. Many equipment items are available from stock. Special equipment can be custom-designed and built, and both standard and special items can be integrated to handle a complete process step. Systems for the absorption of hydrogen chloride in water to produce hydrochloric acid use impervious graphite equipment throughout. Usually, absorption is done in a falling-film absorber (17), a special design adaption of the shell and tube heat exchanger. This approach to absorption of hydrogen chloride (18) was developed and expanded in the United States and is now accepted as the standard.  [c.515]

S. N. Denting and S. L. Morgan, Experimental Design A Chemometric Approach Elsevier Science Publishing Co., Inc., Amsterdam, The Netherlands, 1987. D. D. Wolff and M. L. Parsons, Pattern Recognition Approach to Data Interpretation Plenum Press, New York, 1983.  [c.431]

There are, however, two areas in which graphic methods have had a significant effect on both process design and process control. The synthesis of heat-exchange networks is an exercise in examination of multiple combinations of hot and cold streams transferring heat across heat-exchanger nodes. The network synthesis methods (103) are intrinsically graphic in approach. An interactive software package, RESHEX (104,105) has been developed to implement this approach. The HEXTRAN program by Simulation Sciences, Inc., is another example of the automation of heat-exchanger network design.  [c.64]

Process synthesis is the step in design when the chemical engineer selects component parts and the interconnection between them to create the flow sheet. This formal approach to design includes developing a representation of the synthesis problem, using a means to evaluate alternatives, and following a strategy to search the almost infinitely large space of possible alternatives. Effective solutions depend heavily on the nature of the synthesis problem being addressed (51,52).  [c.80]

There is, however, only a limited quantity of by-product power available, and for large process operations the demand for power is usually far greater than the simple steam cycle can produce. Many steam system design decisions fall back to the question of how to raise the ratio of by-product power to process heat. One simple approach is to limit the turbines that are used to extract power to large sizes, where high efficiency can be obtained.  [c.224]

Field-flow fractionation (FFF) is a set of high resolution liquid chromatography-like elution methods used for sizing and sepai ation of a wide range of particulate, colloidal and macromoleculai materials. Recently the authors have shown that rotating coiled columns (RCC) traditionally applied to separation of different solutes by countercurrent chromatography can be used in FFF methods. A column of a certain configuration rotates ai ound its axis and simultaneously revolves ai ound the central axis of the planetary centrifuge. The asymmetrical centrifugal force field, acting on the RCC, provides different migration speeds of particles in one carrier fluid. As compai ed to the conventional sedimentation FFF (the sepai ation is performed in a one narrow channel) the restriction for particle mass in the sample is avoided in RCC because column volume can be varied through varying the number of turns and layers of the coil. Planetary centrifuge design par ameters have a great influence on the fractionation process this can be used for optimization of separ ation conditions. It has been shown, that fractionation of suspended sample components can be achieved mainly by successive changing fluid pumping rate at a constant value of column rotation speed. The behavior of particles in RCC was studied by the examples of latex, silica gels and natural quartz sand particles of irregular shape. A theoretical model, describing the separ ation process according to design, operation par ameters of RCC, and properties of particles has been proposed. On the basis of experimentally studied dependences of fractionation and retention of different particles and theoretical model, optimal conditions of soil samples separ ation into sill, clay and sand fractions have been selected. RCC can be also applied to the dynamic fractionation of trace elements in each fraction that may help to obtain detailed information about distribution of toxic elements in environmental samples. It may be concluded that the use of RCC for studies on the mobility of heavy metals in soils and sediments provides the basis for a new comprehensive approach to the speciation analysis of environmental samples.  [c.445]

CIA 1990. A Approach to the Categorization of Process Plant Hazard and Control Building Design. Prepared by Working Group 3 of the Major Hazards Steering Group. Issued by the Safety Committee of the Chemical Industry Safety and Health Council of the Chemical Industries Association, Eondon.  [c.148]

Two elements of process safety that deal with human performance are procedures and training. These elements benefit from using an engineering approach to determine which procedures to write and what training needs to be conducted. This systematic approach can help keep a plant s procedures and training program accurate and effective as the facility and people change. The Instructional Systems Design (ISD) model (shown in graphic form on page 204) provides just such an approach. It consists of five phases  [c.203]

This case study discusses the design of a reciprocating mechanical press for the manufacture of can lids drawn from sheet steel material. The authors were involved in the early stages of the product development process to advise the company designing the press in choosing between a number of design alternatives with the goal of ensuring its reliability. The authors used a probabilistic approach to the problem to provide the necessary degree of clarity between the competing solutions.  [c.244]

Chapter 3 reports on a methodology for the allocation of capable component tolerances within assembly stack problems. There is probably no other design effort that can yield greater benefits for less cost than the careful analysis and assignment of tolerances. However, the proper assignment of tolerances is one of the least understood activities in product engineering. The complex nature of the problem is addressed, with background information on the various tolerance models commonly used, optimization routines and capability implications, at both component manufacturing and assembly level. Here we introduce a knowledge-based statistical approach to tolerance allocation, where a systematic analysis for estimating process capability levels at the design stage is used in conjunction with methods for the optimization of tolerances in assembly stacks. The method takes into account failure severity through linkage with FMEA for the setting of realistic capability targets. The application of the method is fully illustrated using a case study from the automotive industry.  [c.416]

The method of approach given here works best if a diagram of the process model is first produced, such as shown in Figure 1. To simplify matrix development and look at the problem as a process design, do not think of the matrix in terms of equations. Rather, the rows are  [c.347]

The design of the magnetic elements forms the backbone of a good switching power supply design. Their proper electrical and physical design have a large affect on the reliable operation of every switching power supply design. Entire books have been written devoted to their design and theory, but in keeping with the premise behind this publication, I have chosen to take a different approach. Since switching power supplies are a specialized narrow application of magnetic elements, the design process for the magnetic elements can be greatly focused and simplified. This yields the quickest working design without having to understand the subtleties involved with each facet of the design. For more detail in the operation of the core materials, refer to Appendix D.  [c.37]

Graphical methods at best are simply illustrative for the student today, but they are occasionally referenced by the process engineer. Extraction, like distillation can be viewed as a stage-wise operation, and hence metliods based on the McCabe Thiele approach briefly described in Chapter 4 have been applied to preliminary design cases. Indeed, both absorption and adsorption are stage-wise operations.  [c.322]

In this chapter each of the principal processing methods for plastics is described and where appropriate a Newtonian analysis of the process is developed. Although most polymer melt flows are in fact Non-Newtonian, the simplified analysis is useful at this stage because it illustrates the approach to the problem without concealing it by mathematical complexity. In practice the simplified analysis may provide sufficient accuracy for the engineer to make initial design decisions and at least it provides a quantitative aspect which assists in the understanding of the process. For those requiring more accurate models of plastics moulding, these are developed in Chapter 5 where the Non-Newtonian aspects of polymer melt flow are considered.  [c.245]

Process safety management is a systematic approach to preventing unwanted releases of hazardous materials from affecting workers and the public/ This encompasses the process technology, procedures, operational and maintenance activities, non-routine activities, emergency preparedness plans, training and other elements and procedures. The defense-in-depth safely that is incorporated into the design and operation of processes, requires evaluation to assure effectiveness. Process safety management anticipates, evaluates and mitigates chemical releases that could result from failure of process procedures/equipment.  [c.67]

A chemical process is an integrated system of interconnected units and streams, and it should be treated as such. Process integration is a holistic approach to process design, retrofitting, and operation which emphasixes the unity of the i ocess. In light of the strong interaction among process units, streams, and objectives, process integration offers a unique framework for fundamentally understanding the global insights of the process, methodically determining its attainable pmfonnance targets, and systematically making decisions leading to the realization of these targets. There are three key components in any comprehensive process integration methodology syntiiesis, analysis, and optimization.  [c.3]

It is virtually impossible to design a fail-safe operation of a chemical process. However, many companies have attempted to minimize liazardous conditions by developing a systematic approach to process design. Implemention of these acdons hoped to aeliieve maximmn protection to personnel, equipment, and die public.  [c.249]

A more recent approach to the problem of electrode coating is the electrodeless magnetic flow meter. In this design there are no electrodes in contact with the process. Large plates placed on the outside of a ceramic spool perform the same function and ate capacitively coupled to the transmitter through a high impedance amplifier. This meter has been found to provide satisfactory service at very low fluid conductivities and under coating conditions where other magnetic flow meters requited cleaning after short periods of operation.  [c.65]

Porous bron2e and iron, a variety of plastics, carbon—graphite, wood, and mbber are widely used in dry sliding or under conditions of sparse lubrication. These materials have commonly allowed design simplifications, freedom from regular maintenance, reduced sensitivity to contamination, and good performance at low speeds and with intermittent lubrication. Although these materials are often used dry or with sparse lubrication, performance normally improves the closer the approach to full-film lubrication.  [c.5]

The more traditional CAD/CAM approaches do, however, have a significant place in chemical process design. The creation and optimization /modification of a process flow diagram lends itself to the CAD / CAM framework. Early work (92) was restricted to the synthesis of piping networks as components of the process flow sheet. A system specifically designed for the creation of process flow diagrams using an experimental program, PEDII, has been described (93,94). PEDII was based on an adaptation of Rubin s graph reduction and embedding procedure to constmct and automatically modify the process flow sheets. In a somewhat different approach (95) a relational database was employed to store and retrieve the symbols for creating the diagram, and interactive methods allowed the user to both create and update the flow diagram.  [c.64]

The capabiHties for computer-aided process design and for utilization of CAD/CAM techniques in association with design have progressed further than similar appHcations in the design of process control systems. Direct appHcation of graphic techniques to the design of process control systems has been limited to certain approaches, for example, one in which graphic display of the frequency response of feedback controUers is used as part of an interactive design method for feedback control systems (100). The CHESOPS program (101) took a similar approach to operabiHty analysis of a process. The basis for performance calculations with the CHESOPS system was a conventional process simulator, which was mn for a number of cases to simulate dynamic behavior. The graphics consisted of a series of two-dimensional plots that explored the feasible operating region for the plant. The optimization of a semibatch free-radical polymerization using interactive CAD tools (102) also used graphic display of computed results as an aid to interactive analysis.  [c.64]

When solids dewatering is known to be a problem early in the process-design stage of a plant or is serious enough to warrant consideration of a range of dewatering alternatives, two approaches are available, and both can be used together. First, processes that begin the dewatering process while in the original suspension may be used. A second approach is to extract water or apply unusual desaturating forces to water present in sludges and cakes. Agglomeration of Suspended Solids.  [c.24]

The Ideal Cascade. A cascade of particular interest to design engineers is the ideal cascade a continuously tapered cascade (ie, F is a continuously varying function of x or n) that has the property of minimi2ing the sum of the stage upflows of all the stages required to achieve a given separation task. Because, in general, the total volume of the equipment required and the total power requirement of the cascade are directiy proportional to the sum of the stage upflows, a consideration of the ideal plant requirements often permits a good economic estimate of the unit cost of product to be made without having to resort to the much more painstaking labor of designing a real (as opposed to ideal) cascade to accomplish the separation job. A simple, intuitive approach to the ideal cascade concept in the case of a cascade composed of discrete stages follows. Again, the resulting equations are also vahd for a cascade based on a continuous or differential separation process.  [c.80]

Cells for the electrolysis of water are available from several sources. These cells have been described (50,51). Water electrolysis cells must operate at low voltages to achieve good energy efficiency. The theoretical decomposition voltage for hydrogen and oxygen production is 1.23 V. Actual cell voltages are 1.8—2.6 V. Current efficiencies closely approach 100%. Cells are usually of a filter-press design incorporating bipolar electrodes, porous diaphragms or ion-exchange membranes, alkaline electrolyte, KOH, and cataly2ed electrodes. Most cells operate at high pressures, about 3 MPa (30 atm) (52,53).  [c.78]

Approach to Heat-Exchanger Design The proper use of basic heat-transfer knowledge in the design of practical heat-transfer equipment is an art. Designers must be constantlv aware of the differences between the ideahzed conditions for and under which the basic knowledge was obtained and the real conditions of the mechanical expression of their design and its environment. The result must satisfy process and operational requirements (such as availability, flexibihty, and maintainaoility) and do so economically. An important part of any design process is to consider and offset the consequences of error in the basic knowledge, in its subsequent incorporation into a design method, in the translation of design into equipment, or in the operation of the equipment and the process. Heat-exchanger design is not a highly accurate art under the best of conditions.  [c.1034]

Trim Coolers Conventional air-cooled heat exchangers can cool the process fluid to within 8.3°C (15°F) of the design dry-biilb temperature. When a lower process outlet temperature is required, a trim cooler is installed in series with the air-cooled heat exchanger. The water-cooled trim cooler can be designed for a 5.6 to 11.1°C (10 to 20°F) approach to the wet-biilb temperature (which in the United States is about 8.3°C (15°F) less than the diy-bulb temperature). In arid areas the difference between diy- and wet-bulb temperatures is much greater.  [c.1080]

Brown, A. D., Hale, P. R. and Parnaby, J. 1989 An Integrated Approach to Quality Engineering in Support of Design for Manufacture. Proc. Instn Mech. Engrs, Part B, 223, 55-63.  [c.383]

An Approach to the Categorisation of Process Plant Hazard and Control Building Design (1990)  [c.553]

Plasticizers, lubricants, fillers, and stabilizers are used to produce the versatility necessary to meet a wide range of applications. PVC, when modified by plasticizers, produces flexible materials which are desirable for certain applications. Elimination of plasticizers results in compounds termed rigid PVC, that are used in other applications. Flexible PVC is generally used for raincoats, baby pants, dolls, shoes, draperies, garden hose, gaskets, shower curtains, show welting, cable and wire insulation, floor covering, coating on hazardous materials handling garments, etc. The principle markets for rigid PVC are pipe, pipe fittings, conduit, ducting, rain gutters and drain spouts, sliding window tracks and other profile extrusions, house siding, decorative trim and edging, bottles, etc. The conventional approach to manufacturing PVC is via suspension polymerization. Monomer droplets are dispersed in water and polymerized using a monomer soluble, free radical initiator. The particle size is controlled in the 100-150 micron range, and the particle porosity is controlled in the 0-50% range by agitation design and by the use of suspending agents which are colloids and wetting agents. The process is an economical one, and residual concentrations of suspending agent, etc. are low, resulting in good electrical properties and chemical resistance. This is the most versatile process, as the particle properties can be tailored to give optimum processing performance with any of a number of plasticizer levels, and types of processing equipment. Other common manufacturing processes for PVC are bulk or mass polymerization and solution polymerization.  [c.239]

Inherently safer design represents a fundamentally different approach to chemical process safety. Rather than accepting the hazards in a process, and then adding on safety systems and layers of protection to control those hazards, the process designer is challenged to reconsider the process and eliminate the hazards. If the designer cannot eliminate the hazards, the challenge becomes to minimize or reduce them as much as possible by modifying the process, rather than by adding external layers, of protection.  [c.24]


See pages that mention the term Approach to process design : [c.705]    [c.43]    [c.231]    [c.705]    [c.504]    [c.158]    [c.250]   
Chemical process design (2000) -- [ c.8 , c.9 , c.10 , c.11 , c.12 ]