Pipeline models

Figure 3.2 A quantitative process pipeline model, illustrating the transfer of successful drug candidates from one stage to the next. Quantitative increases in drug candidate sample-generation volume are complemented by proportional increases in resources for sample analysis. (Courtesy of Milestone Development Services, Newtown, Pa., USA.)...

After the emulsion viscosity is estimated, friction factor charts may be used directly to determine the flow regime (laminar or turbulent) and the pressure gradient. Emulsion viscosity may be used as an input to a standard pipeline model. Nevertheless, it is strongly recommended that pilot-plant testing be completed on new crude oils before commercial application. 

Some workflow systems can break a dataset up into smaller chunks for parallel processing or for other advantages of flexibility derived from the pipeline model. 

Interfacing the Method-of-Characteristics pipeline model to the rest of the process simulation boundary conditions... 

Pipelined models Quite often the signal-to-signal model is implemented as a pipelined model were the process is seen as one of passing representations from one module to the next. Each module performs one specific task such as part-of-speech tagging, or pause insertion and so on. No explicit distinction is made between analysis and synthesis tasks. These systems are often highly modular, such that each module s job is defined as reading one type of information and producing another. Often the modules are not explicitly linked so that different theories and techniques can co-exist in the same overall system. 

Operator Training and Operator Support using Multiphase Pipeline Models and Dynamic Process Simulation Sub-Sea Production and On-Shore Processing... 

UKRC proposed an alternative to flie leaky pipeline model an holistic conceptual approach to the problem of women s under-representation in SET, with its emphasis on the interconnectedness of toe different problem areas. The UKRC s most significant achievements have not been in directly increasing the numbers of women participating in SET education or employment. Instead, it has been effective in two... 

Khan, A. R., and J. F. Richardson. 1996. Comparison of coarse slurry pipeline models. In Proceedings of Hydrotransport 13, pp. 259-281. Cranfield, UK BHR Group. 

Thesing, S. Safe and Precise WCET Determinations by Abstract Interpretation of Pipeline Models. PhD thesis, Saarland University (2004)... 

O Rourke et al. (1995) proposed an inelastic pipeline model to analyze the response of pipelines to longitudinal PGD. Figure 5 shows the considered model. To develop this model O Rourke et al. utilized an idealized block pattern in which a mass of soil having length L moves down a slight incline. The soil displacement on either side of the PGD zone is zero, while the soil displacement within the zone is a constant value 5. 

The above example is a simple one, and it can be seen that the individual items form part of the chain in the production system, in which the items are dependent on each other. For example, the operating pressure and temperature of the separators will determine the inlet conditions for the export pump. System modelling may be performed to determine the impact of a change of conditions in one part of the process to the overall system performance. This involves linking together the mathematical simulation of the components, e.g. the reservoir simulation, tubing performance, process simulation, and pipeline behaviour programmes. In this way the dependencies can be modelled, and sensitivities can be performed as calculations prior to implementation. 

The AUGUR information on defect configuration is used to develop the three-dimensional solid model of damaged pipeline weldment by the use of geometry editor. The editor options provide by easy way creation and changing of the solid model. This model is used for fracture analysis by finite element method with appropriate cross-section stress distribution and external loads. 

Arzhaev A.I., Bougaenko S.E., Smirnov Yu.I., Aladinsky V V, Makhanev V.O., Saburov Yu. Residual stress modelling and analysis for INPP primary circuit pipeline welds. Transactions of the 14th Int. Conf. on Structural Mechanics in Reactor Technology (SMiRT 14), Lyon, 1997, Vol. 1, Div, B, pp. 345-352. 

The GammaMat M isotope pipeline crawlers previously have been used with exposure cameras for iridium the models M6 and Ml 8 used exposure units designed for a maximum loading of 2.2 TBq (60Ci) and 3.7 TBq (lOOCi), respectively. 

Practical applications [2] of a GammaMat M model using the new Selenium crawler camera loaded with approx. 1 TBq (30Ci) on a pipeline of diameter 12 and wall thickness of 0.25 showed 6-7 m axial distance to the exposed source as limit of the radiation controlled area (40pSv/h) and 22m perpendicular to the pipeline. Other authors [3] have reported about a comparison for Ir-192 and Selenium source on a 4.5 diameter pipe and 0,125 steel thickness they have found for 0.7 Tbq (18Ci) Selenium a value of 1 Om behind the film (in the unshielded beam) comparing under same conditions to approx. 40m for Iridium. 

FIAZOP is a formally struetured method of systematieally investigating eaeh element of a system for all ways where important parameters ean deviate from the intended design eonditions to ereate hazards and operability problems. The HAZOP problems are typieally determined by a study of the piping and instrument diagrams (or plant model) by a team of personnel who eritieally analyze eflfeets of potential problems arising in eaeh pipeline and eaeh vessel of the operation. 

In a series of experiments on the flow of flocculated kaolin suspensions in laboratory and industrial scale pipelines(26-27-2Sl, measurements of pressure drop were made as a function of flowrate. Results were obtained using a laboratory capillary-tube viscometer, and pipelines of 42 mm and 205 mm diameter arranged in a recirculating loop. The rheology of all of the suspensions was described by the power-law model with a power law index less than unity, that is they were all shear-thinning. The behaviour in the laminar region can be described by the equation ... 

The two-layer model is being progressively updated as fresh experimental results and correlations become available. The most satisfactory starting-point for anyone wishing to use the model to calculate pressure gradients for flow of solids-liquid mixtures in a pipeline is the text of SHOOK and Roc.o(52) which includes a worked example. However, there are many pitfalls to be avoided in this area, and there is no substitute for pracucal experience gained by working in the field. 

A homogeneous flow basis must be used when thermodynamic equilibrium is assumed. For furtl er simplification it is assumed there will be no reaction occurring in the pipeline. The vapor and liquid contents of the reactor are assumed to be a homogeneous mass as they enter the vent line. The model assumes adiabatic conditions in the vent line and maintains constant stagnation enthalpy for the energy balance. 

Laminar Pipeline Flows. The axial dispersion model can be used for laminar flow reactors if the reactor is so long that At/R > 0.125. With this high value for the initial radial position of a molecule becomes unimportant. 

Correlations for E are not widely available. The more accurate model given in Section 9.1 is preferred for nonisothermal reactions in packed-beds. However, as discussed previously, this model degenerates to piston flow for an adiabatic reaction. The nonisothermal axial dispersion model is a conservative design methodology available for adiabatic reactions in packed beds and for nonisothermal reactions in turbulent pipeline flows. The fact that E >D provides some basis for estimating E. Recognize that the axial dispersion model is a correction to what would otherwise be treated as piston flow. Thus, even setting E=D should improve the accuracy of the predictions. 

Example 9.6 Compare the nonisothermal axial dispersion model with piston flow for a first-order reaction in turbulent pipeline flow with Re= 10,000. Pick the reaction parameters so that the reactor is at or near a region of thermal runaway. 

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