Functional pipelining

Cooling water pipes are essential for the operation of power stations and must not cease to function. Pipelines for fire fighting are also important for safety reasons. Such steel pipelines are usually well coated. At areas of unavoidable damage to the pipe coating, there is an increased danger due to cell formation between steel and concrete where local corrosion rates of >1 mm a are to be expected [4], Damage to pipelines for fire fighting has frequently been observed after only a few years in service. 

E.P. Girczyc, Loop Winding — A Data Flow Approach to Functional Pipelining , Proc. of ISCAS 87, pages 382-385, May 1987. 

We treat the high-performance scheduling of loc s as a special case of functional pipelining. This will be described in the next section. 

The force-directed scheduling framework also supports two forms of pipelining functional pipelining [10], [11] and structural pipelining [12]. 

Figure 11. Schedule obtained using functional pipelining extension.

E.F. Girczyc, "Loop Winding — a Data Flow Approach to Functional Pipelining", Proc, of the International Symposium on Circuits and Systems (ISCAS), Philadelphia, May 1987, pp. 382-385. 

The concept of loop folding is very similar to that of function pipelining. The only difference is that in loop folding, there exists data dependencies across loop iterations, while in function pipelining, there is no data dependency between instances. 

For large problems, the zone scheduling is applied. The pipeline list scheduling can be used in functional pipelining and loop folding. 

The first function of a wellsite is to accommodate drilling operations. However, a wellsite must be designed to allow access for future operations and maintenance activity, and in many cases provide containment in the event of accidental emission. Production from a single wellhead or wellhead cluster is routed by pipeline to a gathering station, often without any treatment. In such a case the pipeline effectively becomes an extension of the production tubing. If a well is producing naturally or with assistance from a down... 

AH corrosion inhibitors in use as of this writing are oil-soluble surfactants (qv) which consist of a hydrophobic hydrocarbon backbone and a hydrophilic functional group. Oil-soluble surfactant-type additives were first used in 1946 by the Sinclair Oil Co. (38). Most corrosion inhibitors are carboxyhc acids (qv), amines, or amine salts (39), depending on the types of water bottoms encountered in the whole distribution system. The wrong choice of inhibitors can lead to unwanted reactions. Eor instance, use of an acidic corrosion inhibitor when the water bottoms are caustic can result in the formation of insoluble salts that can plug filters in the distribution system or in customers vehicles. Because these additives form a strongly adsorbed impervious film at the metal Hquid interface, low Hquid concentrations are usually adequate. Concentrations typically range up to 5 ppm. In many situations, pipeline companies add their own corrosion inhibitors on top of that added by refiners. 

Before the creation of the U.S. DOT in 1967, the now defunct ICC was authorized to prescribe rules and regulations for rad, tmck, and pipeline safety. The Federal Aviation Administration (FAA) was responsible for air safety, and the U.S. Coast Guard for safety on the inland and coastal waterways. Upon estabHshment of DOT in 1967, the FAA and Coast Guard were transferred to the DOT, which assumed the safety functions the ICC formerly adrninistered. 

Fig. 10-1 Length of the protected range 2 Z- as a function of pipe wall thickness and proteetion eurrent density from Eq. (10-5) the pipeline (p, = 0.18 X 10 m, 5 = 8 mm DN 600) with insulated soekets is bridged by 0.5-m NY Y eable of 16 mm eopper.

The protection station must be carefully maintained (see Section 10.5). The function of the rectifier should be monitored at monthly intervals. The pipe/soil potentials of the pipelines should be measured at least once a year. The IR-free potentials should be determined as far as possible by the switching method, especially when new pipework is installed and connected to the protection system. 

Nonuniform corrosion or pitting corrosion frequently occurs on steel structures in seawater and in soil. Nonuniform and pitting corrosion easily lead to damage in tanks, pipelines, water heaters, ships, buoys and pontoons, because these structures lose their functional efficiency when their walls are perforated (see Chapter 4). 

Fig. 22-3 (1) Total number of wall penetrations by corrosion per kilometer of a DN 500 pipeline as a function of service life. (2) Total number of wall penetrations per kilometer of a pipeline with severe stray current exit.

Fig. 23-12 Limiting lengths for parallel run of high-voltage overhead power line and pipeline as a function of distance, a.

A vital part of the process system for each of the plants includes a turboexpander-compressor set. This turbomachinery string has two main functions. The first function reduces the pressure and temperature of the incoming gas to facilitate separation of the methane. The second function raises the pressure of the methane after it leaves the fractionation tower and is transferred directly to the customers through an underground pipeline. 

Valves have two main functions in a pipeline to control the amount of flow, or to stop the flow completely. There are many different types but the most commonly used are the gate valve and the globe valve. The gate valve contains a disk that slides at right angles to the flow direction. This type of valve is used primarily for on-off control of a liquid flow. Because small lateral adjustments of the disk cause e.xtreme changes in the flow cross-sectional area, this type of valve is not suitable for adjusting flow rates. 

Transportation of natural gas across state lines from production to consuming areas is a function of interstate pipeline companies. The modern U.S. natural gas industry also includes natural gas exploration and production companies, intrastate pipelines, local distribution companies (LDCs), end-users and, the most recent addition to the industry, marketers. 

Figure 2-49. Slurry flow regime (heterogeneous, homogeneous) is a function of solid s size and specific gravity. By permission, Der-annelaere, R. H. and Wasp, E. J., "Fluid Flow, Slurry Systems and Pipelines," Encyclopedia of Chemical Processing and Design, J. Mc-Ketta, Ed., M. Dekker, vol. 22,1985 [25].

Oil fuel pipeline systems transfer oil from storage to the oil burner at specified conditions of pressure, viscosity, temperature and rate of flow. There can be considerable variety in the choice of system, but its design (particularly correct pipe sizing and temperature control) is most important if it is to function satisfactorily. 

Offshore, both Ag/AgCl and metallic zinc electrodes are used for potential measurements and are also employed for current density surveys undertaken on the offshore platforms and pipelines, as discussed below. It has been found beneficial for offshore applications to install together an electrode of each type on a structure, one acting as a function check on the other. ... 

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