Pressure vessel optimization

Optimization of Cycle Times. In batch filters, one of the important decisions is how much time is allocated to the different operations such as filtration, displacement dewatering, cake washing, and cake discharge, which may involve opening of the pressure vessel. Ah. of this has to happen within a cycle time /. which itself is not fixed, though some of the times involved may be defined, such as the cake discharge time. 

Suppose you wanted to find the configuration that minimizes the capital costs of a cylindrical pressure vessel. To select the best dimensions (length L and diameter D) of the vessel, formulate a suitable objective function for the capital costs and find the optimal (LID) that minimizes the cost function. Let the tank volume be V, which is fixed. Compare your result with the design rule-of-thumb used in practice, (L/D)opt = 3.0. 

After reviewing the literature, the scientist set out on optimization of the first key step, a SnAt reaction. Typical SnAt reaction conditions were initially attempted, examples of which can be seen in Table 8.4. Typical reflux heating in solvents such as DMF and DMSO provided poor yields of the desired products even after prolonged heating. Only with the use of a pressurized vessel were the satisfactory levels of the desired product obtained. However, it should be pointed out that under typical library production conditions, sealed tubes could not be used to produce the desired compounds, and in all actuality the use of refluxing DMSO would also be problematic. After examining... 

Correct SRV sizing, selection, manufacture, assembly, testing, installation and maintenance as described in this book are all critical for the optimal protection of the pressure vessel, system, property and life. This book explains the fundamental terminology, design and codes to allow most engineers to make the correct decisions in applying SRVs in the process industry and to improve the safety to higher levels. 

The reaction of a strong solution of aqueous ammonia with the sulfide concentrate in a strongly agitated pressure vessel at a temperature between 160 and 190°F under an oxygen partial pressure of about 10 psi, either as pure oxygen or as compressed air, fulfills the optimal conditions for the above requirements. The iron present in the concentrate is oxidized to hydrated ferric oxide which, together with the silicates is insoluble in aqueous ammonia. The copper, nickel, and cobalt form their amines, while the sulfides are oxidized to sulfates, thiosulfates, and polythionates. 

This can be illustrated by a simple reactor optimization example. The size and cost of a reactor are proportional to residence time, which decreases as temperature is increased. The optimal temperature is usually a trade-off between reactor cost and the formation of byproducts in side reactions but if there were no side reactions, then the next constraint would be the maximum temperature allowed by the pressure vessel design code. More expensive alloys might allow for operation at higher temperatures. The variation of reactor cost with temperature will look something like Figure 1.8, where T, Tg, and Tc are the maximum temperatures allowed by the vessel design code for alloys A, B, and C, respectively. 

A direct industrial process to obtain vinylsilanes is the addition of silanes (e.g. 51) to acetylene and its derivatives which has to be conducted at higher temperatures in a pressure vessel (equation 27)43. A major challenge is to determine the correct reaction period with an optimal reagent substrate ratio in order to avoid further reaction to the corresponding disilylalkanes. 

The estimation of the optimal pressure was previously discussed by taking into account the possible pressure dependence of [2] as well as the interrelation of pressure and temperature defined under isokinetic conditions [3], The relationship (Eq. (10.1)) underlines that the rate constant increases exponentially with pressure. The logarithmic behavior is illustrated in Fig. 10.1 which shows the variation of the rate constant ratio fep/ko with pressure at 25 °C. As an example, let us consider a pressure of 300 MPa which is usually an upper limit for large commercial pressure vessels. At that pressure the value of fep/fco approaches 10-40 for pressure-... 

The optimal design of a laboratory isothermal BR would therefore consist of a well insulated closed pressure vessel with a stirrer, an internal electric heater, an internal cooling device, and a thermal sensor properly placed inside the vessel. The stirrer, cool-ing/heating surfaces and the sensor would require careful positioning to achieve uniformity of temperature and composition, but it can be done in a sufficiently large vessel. Unfortunately most research reactors are small and the above requirements mean that the BR is not often used in kinetic investigations. Its merit, when it can be used without encountering the above concerns, is that it is relatively simple to construct and operate and requires a limited amount of reactants. 

Optimal length (or height) and diameter of a cylindrical pressure vessel of a given volume to minimize the capital cost. 

The whole membrane module is composed of six racks, each of them consisting of eleven pressure vessels, operated in parallel, designed to house one spiral wound membrane each. The pressure vessels were originally equipped with cellulose acetate membranes specifically developed for PRO. During the first period, the plant operation has been optimized and the performance has been monitored, resulting in a power density lower than 0.5 W/m. Next, thin film composite membranes developed for PRO were installed in early 2011. So far the measured power density has reached nearly 1 W/m, which is a major improvement compared to the cellulose acetate membranes originally installed. Based on this preliminary experience, Statkraft plans to build a full-scale 25 MW osmotic power plant by 2015 [20]. 

The modules will be standardized units, well adapted for shop fabrication in series. The concrete pressure vessel is constructed at site, of course, but the construction of the huge vessel is not considered to be any great problem, according to Swedish constructing companies. A total construction period of about 4.5 years can be achieved by optimized construction sequence and methods. 

Components that are critical for success include the hydrogen tank (pressure vessels) and the electric machines, which can be responsible for two-thirds of fuel cell drivetrain costs. Production and assembly processes can lead to learning effects and possible cost reductions. Fuel cell systems need to be optimized for their automotive application, for example, in terms of durability, packaging and start-up behavior. 

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