Deacon process

Deacon equilibrium Deacon process Deacon reaction Deactivating groups Deactivation  [c.280]

The high cost of energy mandates carefully plaimed heat-exchange networks for economically and environmentally viable plants (see HeaT-EXCHANGE TECHNOLOGY, heattransfer). The process of developing a good heat-exchange or energy network is most easily viewed as a multiple-tier optimization problem. Minimum lifetime plant cost is the objective. The complexity of the design process leads to multiple optimizations of the energy subsystem. The process includes minimizing capital and operating costs plus an emphasis on developing a robust design that includes the necessary flexibiUty and operabihty characteristics.  [c.517]

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]

Standard procedures for fracture toughness testing of materials give reproducible values of minimum fracture toughness, but Httle guidance is available for incorporating these values into the design process (109). A design philosophy for the avoidance of unstable fracture in high pressure components based on LEFM has been given (91) for all practical combinations of yield stress and fracture toughness an LEFM analysis proves conservative except in the case of very thick-walled components.  [c.90]

The rate of this reaction is significantly enhanced over catalysts such as copper chloride which is the basis for the Deacon process for producing CI2 from HCl. The relationship between the equilibrium constant and the temperature in Kelvin for the reaction is expressed by equation 19.  [c.444]

Chlorine. Several methods are available for generating chlorine from HCl. These include electrolysis of metallic chloride solutions, electrolysis of hydrochloric acid, oxidation of hydrogen chloride to chlorine with nitric acid, and oxidation of hydrogen chloride to chlorine using oxygen in the presence of catalysts (Deacon process and the modified Deacon process). As of this writing, only about 60,000 to 65,000 metric tons of CI2 is produced via electrolysis of HCl in the United States annually. Details related to electrolytic and chemical routes for manufacturing CI2 from HCl are given in the hterature (89) (see Alkali and cm ORiNE products, cm ORiNE and sodiumhydroxide).  [c.450]

The UCB collection and refining technology (owned by BP Chemicals (122,153—155)) also depends on partial condensation of maleic anhydride and scmbbing with water to recover the maleic anhydride present in the reaction off-gas. The UCB process departs significantly from the Scientific Design process when the maleic acid is dehydrated to maleic anhydride. In the UCB process the water in the maleic acid solution is evaporated to concentrate the acid solution. The concentrated acid solution and condensed cmde maleic anhydride is converted to maleic anhydride by a thermal process in a specially designed reactor. The resulting cmde maleic anhydride is then purified by distillation.  [c.457]

S. E. Ereeman and R. M. Dawson, Prog. Neurohiol 36, 257 (1991).  [c.102]

As for the a-hehcal proteins, aU. of the P-designed proteins stiU possess some characteristics of the molten globule state. Thus, whereas the hydrophobic force plays a dorninant role in the folding of a protein, it is not one that is sufficient to define the unique tertiary stmcture of native proteins. To design a truly native-like protein de novo, specific side-chain interactions which adopt unique packing characteristics must be part of the design process. Design efforts aimed toward reaching this goal are ongoing in several laboratories.  [c.203]

In oxychlorination, ethylene reacts with dry HCl and either air or pure oxygen to produce EDC and water. Various commercial oxychlorination processes differ from one another to some extent because they were developed independentiy by several different vinyl chloride producers (78,83), but in each case the reaction is carried out in the vapor phase in either a fixed- or fluidized-bed reactor containing a modified Deacon catalyst. Unlike the Deacon process for chlorine production, oxychlorination of ethylene occurs readily at temperatures weU below those requited for HCl oxidation.  [c.417]

Ethylene oxide (qv) was once produced by the chlorohydrin process, but this process was slowly abandoned starting in 1937 when Union Carbide Corp. developed and commercialized the silver-catalyzed air oxidation of ethylene process patented in 1931 (67). Union Carbide Corp. is stiU. the world s largest ethylene oxide producer, but most other manufacturers Hcense either the Shell or Scientific Design process. Shell has the dominant patent position in ethylene oxide catalysts, which is the result of the development of highly effective methods of silver deposition on alumina (29), and the discovery of the importance of estabUshing precise parts per million levels of the higher alkaU metal elements on the catalyst surface (68). The most recent patents describe the addition of trace amounts of rhenium and various Group (VI) elements (69).  [c.202]

Where possible design process and/or restructure job/tasks to reduce need for personal protection equipment (PPE)  [c.137]

Adequacy of the Quality Systems supported through Quality Assurance Plans (QAPs). in design, process, installation and servicing.  [c.249]

The eomplex FCC system involves not only turbomaehinery, but also related proeess eomponents. All of these must be properly designed and sized to operate within system parameters from startup to steady state design point, and through shutdown. System response to emergeney eonditions is also mandatory. Computer simulation is, therefore, an integral part of the design proeess. A eomputer program eapable of this simulation is deseribed below.  [c.185]

This is poor risk management. Applied to a turboexpander in eritieal serviee it translates into bad business praetiee. This segment will deseribe three baste strategies appropriate for turboexpanders (and indeed all rotating maehinery). The ehoiee of strategy should not be left to the manufaeturer. It needs to fit the operator s speeifie appli-eation and eomfort level. The manufaeturer s resourees and teehnieal expertise should be used to support the deeision proeess by providing relevant information.  [c.401]

As seen in Figure 1.19, the important results from an FMEA in terms of designing capable and reliable products are the potential failure modes, severity rating and critical characteristics for the design. By identifying the capability of the critical characteristics, and the potential failure mode, a statistical analysis can then be performed to determine its reliability. The FMEA Severity Rating (S) is crucial for setting capability and reliability targets because it is a useful indication of the level of the safety required for the application. Although subjective in nature, the effective use of an FMEA in the design process is advocated as it brings significant benefits.  [c.25]

More plausible representations of stress and strength distributions for a given situation will enable meaningful failure predietions to be produeed, and will be partieularly useful where test to failure is not a praetieal proposition, where weight minimization and/or material eost reduetion is important, or where development time is erueial. Engineering experienee indieates that many deviees are overdesigned, that is, they feature exeess weight or exeess oeeupied spaee. When weight and/or spaee is at a premium, a more realistie design proeess is required that permits relatively aeeurate predietions of deviee performanee. A probabilistie design proeess, taking into aeeount of the uneertainties with typieal design inputs, provides the required realism (Bury, 1975).  [c.32]

Reliability prediction techniques are a controversial but fundamental approach for designing for reliability. A key objective of these methods is to provide the designer with a deeper understanding of the critical design parameters and how they influence the adequacy of the design in its operating environment. These variables include dimensions, material properties and in-service loading. A key requirement is detailed knowledge about the distributions involved to enable plausible results to be produced in an analysis. It is largely the appropriateness and validity of this input information (and failure theory) that determines the degree of realism of the design process and the ability to accurately predict the behaviour and therefore the success of the design. The determination of an absolute value of reliability is impossible. In developing a product, a number of design schemes or alternatives should be generated to explore each for their ability to meet the target requirements. Evaluating and comparing designs and choosing the one with the greatest predicted reliability, or quality for that matter, will provide the most effective design solution.  [c.35]

The knowledge eontained in the maps is also useful in determining the toleranee requirement at an early stage in the detailed design proeess. In this eapaeity, the region of proeess eapable toleranee is bounded by two bold lines at = 1 and = 1.7 on the maps. Of eourse, this does not take into eonsideration the material and geometry effeets initially, for example parting line allowanees. Referenee to Swift and Booker (1997) ean be made for approximate parting line allowanees. In most eases, guidanee is also given on the maps for the need of a seeondary proeess if the dimension/toleranee eombination defined gives a risk index greater than 3 (whieh is eonsidered to be out of manufaeturing eontrol).  [c.53]

Usually, the assembly sequenee of the eomponents that make up the produet is examined late in the design proeess when manufaeturing engineers are trying to  [c.61]

Evaluating and comparing designs - CA may be used to evaluate alternative concepts or schemes that are generated to meet the specification requirements. It highlights the problem areas of the design, and calculates the failure cost of each, which acts as a measure of quality for the design. Since the vast majority of cost is built into a component in the early stages of the design process, it is advantageous to appraise the design as honestly and as soon as possible to justify choice in selecting a particular design scheme.  [c.76]

Through performing an analysis using CA, many modes of applieation have been highlighted. This has resulted from the way that the CA design performanee measures allow a non-judgemental language to develop between the design team. It has also been found not to inhibit the design proeess, but provide a struetured analysis with whieh to traee design deeisions. The knowledge embedded within CA also allows the designer to generate proeess eapable solutions and open up diseussion with suppliers. The analysis is eurrently faeilitated through the use of a paper-based assessment. This has many benefits, ineluding improved team working, and provides  [c.107]

Swift, K. G. and Allen, A. 1994 Product Variability Risks and Robust Design. Proc. Instn Mech. Engrs, Part B, 208, 9-19.  [c.392]

D. J. Salley, A. J. Weith Jr., A. A. Argyle, and J. K. Dixon, Proc. Roy. Soc. (London), A203, 42 (1950).  [c.99]

Aqueous solubility of organic compounds is a particularly useful property, having many applications in pharmaceutical, environmental, and other chemical disciplines. The solubility of a drug is an important property that determines its bioa-vailability and biological activity. In the drug design process, it is essential to estimate the solubility of a large number of candidates for a drug before the compound is synthesized. A knowledge of aqueous solubility is also necessary for predicting the general environmental distribution of organic pollutants such as highly toxic, carcinogenic, and other undesirable compounds.  [c.495]

Whereas process simulation includes quantitative analysis of a design given the stmcture of the design, process synthesis involves determining the stmcture that will meet the requirements of the design as well as finding the best stmcture for the requirements. For example, if components A, B, C, and D whose relative volatOities were in the order D, C, B, and A were to be separated by distillation for which each column produced a top and a bottom fraction, five schemes of three columns arise as possible stmctures (53) (Fig. 8).  [c.80]

Activated alumina and phosphoric acid on a suitable support have become the choices for an iadustrial process. Ziac oxide with alumina has also been claimed to be a good catalyst. The actual mechanism of dehydration is not known. In iadustrial production, the ethylene yield is 94 to 99% of the theoretical value depending on the processiag scheme. Traces of aldehyde, acids, higher hydrocarbons, and carbon oxides, as well as water, have to be removed. Fixed-bed processes developed at the beginning of this century have been commercialized in many countries, and small-scale industries are still in operation in Brazil and India. New fluid-bed processes have been developed to reduce the plant investment and operating costs (102,103). Commercially available processes include the Lummus processes (fixed and fluidized-bed processes), Halcon/Scientific Design process, NIKK/JGC process, and the Petrobras process. In all these processes, typical ethylene yield is between 94 and 99%.  [c.444]

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]

One benefit of the hairpin exchanger is its ability to handle high tube-side pressures at a lower cost than other removable-bundle exchangers. This is due in part to the lack of pass partitions at the tubesheets which complicate the gasketing design process. Present mechanical design technology has allowed the building of dependable, removable-bundle, hairpin multitubes at tubeside pressures of 825 bar (12,000 psi).  [c.1077]

Much of the experience and data from wastewater treatment has been gained from municipal treatment plants. Industrial liquid wastes are similar to wastewater but differ in significant ways. Thus, typical design parameters and standards developed for municipal wastewater operations must not be blindly utilized for industrial wastewater. It is best to run laboratory and small pilot tests with the specific industrial wastewater as part of the design process. It is most important to understand the temporal variations in industrial wastewater strength, flow, and waste components and their effect on the performance of various treatment processes. Industry personnel in an effort to reduce cost often neglect laboratory and pilot studies and depend on waste characteristics from similar plants. This strategy often results in failure, delay, and increased costs. Careful studies on the actual waste at a plant site cannot be overemphasized.  [c.2213]

Viscosity of reactor Design process to work within agitator contents increases limitations dramatically with, Design agitator to account for property varia-the extent of reac- progress tion. Mixing becomes more dif- Monitor shaft speed ficult as reaction Design system to accommodate maximum proceeds. This may expected pressure and temperature lead to hot spots, Provide emergency relief device due to insufficient mixing or inade- Monitor viscosity quate heat transfer Add diluent to reduce viscosity rates resulting in, Monitor agitator power input runaway initiation. CCPS G-29 Kletz 1991 Lees 1996  [c.60]

AC Good, R Lewis. New methodology for profiling combinatorial libraries and screening sets Cleaning up the design process with HARPick. I Med Chem 40 3926-3936, 1997.  [c.369]

Cataljdic reactions performed in fluid beds are not too numerous. Among these are the oxidation of o-xylene to phthalic anhydride, the Deacon process for oxidizing HCl to CI2, producing acrylonitrile from propylene and ammonia in an oxidation, and the ethylene dichloride process. In the petroleum industry, cataljdic cracking and catalyst regeneration is done in fluid beds as well as some hydroforming reactions.  [c.183]

Variations in a produet s material properties, serviee loads, environment and use typieally lead to random failures over the most protraeted period of the produet s expeeted life-eyele. During the eonditions of use, environmental and serviee variations give rise to temporary overloads or transients eausing failures, although some failures are also eaused by human related events sueh as installation and operation errors rather than by any intrinsie property of the produet s eomponents (Klit et al., 1993). Variability, therefore, is also the souree of unreliability in a produet (Carter, 1997). However, it is evident that if produet reliability is determined during the design proeess, subsequent manufaeturing, assembly and delivery of the system will eertainly not improve upon this inherent reliability level (Kapur and Lamberson, 1977).  [c.21]

Reliability prediction is undoubtedly an important aspect of the product design process, not only to quantify the design in terms of reliability, but also to determine the critical design parameters that go to produce a reliable product. To this end, it is necessary to have a mathematical, quantitative measure of reliability defined by probability (Leitch, 1995). It is, however, a controversial aspect of reliability engineering in terms of accuracy and validity because it relies on detailed knowledge about sometimes unknown design parameters (Burns, 1994 Carter, 1986 O Connor, 1995). In addition, the practical engineering of reliability in the product is still seen as a science to many designers and evaluating concept designs for reliability is especially difficult for inexperienced staff (Broadbent, 1993). A fundamental reason for this is the supporting use of statistics and probability theory. Designers and engineers have consistently turned a blind eye to the advantages of using these methods however, they can be trained to use them without being rigorously schooled in their mathematical foundation (Morrison, 1997). Reliability prediction will remain a controversial technique until the statistical methods for quantifying design parameters becomes embedded in everyday engineering practice. Using statistically based design techniques will not solve the whole problem, although it will be much closer to the desired end result (Carter, 1997).  [c.30]

Designers rarely fully understand the manufaeturing systems that they are designing for, and subsequently they do not understand the variability assoeiated with the design eharaeteristies. Variability ean have severe repereussions in terms of failure eosts, appearing in produetion due to rework and serap, and warranty eosts (or worse ) when the produet fails in serviee. There is need to try to antieipate the variability assoeiated with the manufaeturing proeesses used to produee the final produet early in the design proeess. The designer needs to know, or else be able to prediet the eapability of the proeess and to ensure the neeessary toleranee limits are sulReiently wide to avoid manufaeturing defeets. However, this has previously been diffieult to aehieve on eoneept design or where little detail exists.  [c.34]

The goal of this first stage of Conformability Analysis (CA), the Component Manufacturing Variability Risks Analysis, is the provision of support in the early stages of the detailed design process for assessing the tolerance and surface finish capability associated with component manufacture. Risk in this sense is a measure of the chances of not meeting the specification. Recognizing that the relationship between a design and its production capability is complex and not easily amenable to precise scientific formulation, the methodology described has resulted largely from knowledge engineering exercises in manufacturing businesses, including those with expertise in particular manufacturing processes. For example, Poeton in Gloucester, UK, specialize in supplying surface coating technology in the form of design guidance and processing techniques. The Poeton engineers had a major consultation role in the determination of the main issues related to surface engineering process variability. To support other aspects of the analysis, such as the tolerance capability analysis, manufacturing tolerance data was readily available, albeit in a form not useful to designers. During the evolution of CA, many alterations and improvements were made through exhaustive consultation and validation in industry. The development of only the current aspects of the analysis will be discussed in detail here. However, some background topics will be reviewed before proceeding.  [c.38]

Process capability indices are not generally specified by designers and subsequently the impact of design decisions made on the production department cannot be fully understood because tolerances alone do not contain enough information. Variability in component manufacture has proved diificult to predict in the early stages of the design process and there are many influencing factors that the designer may not necessarily be able to anticipate. The material and geometrical configuration of the design, and the compatibility with the manufacturing process are the main variability drivers. Although design rules and general manufacturing capability information are available, they are rarely presented in a useful or practical form, especially when innovative design is required. There is a need to set realistic tolerances and anticipate the variability associated with the design to help reduce failure costs later in the product s life-cycle.  [c.106]

The ductile-to-brittle transition temperature for some steels ean be as high as O C, depending on the eomposition of the steel (Ashby and Jones, 1989). However, there is no way of using the data direetly from impaet tests quantitatively in the design proeess. Design speeifieations do usually state a minimum impaet strength, but experienee suggests that this does not neeessarily eliminate brittle failure (Faires, 1965). The Robertson test ean yield more information than either the Charpy or Izod tests beeause the transition temperature is statistieally eorrelated with the temperature at whieh the aetual strueture has been known to fail in a brittle manner (Benham and Warnoek, 1983 Ruiz and Koenigsberger, 1970). The test uses a severely notehed speeimen tested under statie tension, and a plot showing the variation of the nominal stress at fraeture with the test speeimen temperature drawn. The test gives useful results from whieh design ealeulations ean be based however, the test is more expensive and eomplex eompared to other methods. In general, it is dangerous to use a material below its transition temperature beeause most of its eapaeity to absorb energy without rupture has been lost and eareful design and analysis is required.  [c.161]

Reliability targets are typically set based on previous product failures or existing design practice (Ditlevsen, 1997) however, from the above arguments, an approach based on FMEA results would be useful in setting reliability targets early in the design process.  [c.197]

In the case where high ioading roughness is expected, as in meciianicai design, simpiy referring to the reiiabiiity target map is sufficient to determine a reiiabiiity ievei which is acceptabie for the given faiiure severity for the component/system eariy in the design process.  [c.201]

As mentioned, eoneurrent engineering prineiples should result in a better quality of the final design however, it may inerease the eomplexity of the design proeess and make it more diifieult to manage (Kusiak and Wang, 1993). The need for effeetive management and eommitment is again emphasized as having a key role in the produet development proeess.  [c.259]

Klit, P., Jensen, F. and Ellevang, P. 1993 Reliable Design Methodology - the use and misuse of reliability data in the design process. In Proceedings ICED 93, The Hague, 1156-1164.  [c.387]

See pages that mention the term Deacon process : [c.219]    [c.418]    [c.1114]    [c.63]    [c.202]    [c.255]    [c.268]   
Modern inorganic chemistry (1975) -- [ c.267 , c.317 , c.318 ]