Pipes size ranges

Traditional chemical reaction engineering deals with smaller sizes, typically with tubing and pipe sizes ranging from about 1 mm to 10 m. This will be termed the macroscale. Table 16.1 provides definitions of three smaller scales meso, micro, and nano. These terms have been used in a variety of ways in the literature. The term mi-croreactor is sometimes used for systems defined here as mesoscale. The definitions in Table 16.1 are rational if somewhat arbitrary. They are based on the characteristic size of flow channels. 

The refinery operators immediately embarked on a program of visual inspection of all amine lines. As of June 1985, a total of 35 leaks in lean amine piping had been discovered. All leaks were at cracks in or around pipe-to-elbow welds, except for two leaks at welds that connected a tee and a reducer, respectively. Piping size ranged from 76 to 305 mm (3 to 12 inches). 

Impervious graphite centrifugal pumps, pipe fittings, and valves were developed because most chemical processes require the movement of Hquids. Graphite pipe and fittings in sizes ranging from 25 to 635 mm ID are used to convey corrosive fluids. 

The various levels of the taxonomy represent factors that have an impact on failure rate. For example, lined pipe (CCPS taxonomy number 3.2.2) has a level that groups pipe into 0-6 size and over 6 . Unless the pipe size is specified, there is no way of knowing whether a given failure rate came from the 0-6 or the over 6 range. 

Durand<62) has also studied vertical transport of sand and gravel of particle size ranging between 0.18 mm and 4.57 mm in a 150 mm diameter pipe, and Worster and Denny 63 conveyed coal and gravel in vertical pipes of diameters 75, 100, and 150 mm. They concluded that the pressure drop for the slurry was the same as for the water alone, if due allowance was made for the static head attributable to the solids in the pipe. 

Equipment manufacturers also work to standards to produce standardised designs and size ranges for commonly used items such as electric motors, pumps, pipes and pipe fittings. They will conform to national standards, where they exist, or to those issued by trade associations. It is clearly more economic to produce a limited range of standard sizes than to have to treat each order as a special job. 

The pitch of the coils and the area covered can be selected to provide the heat transfer area required. Standard pipe sizes are used ranging from 60 to 120 mm outside diameter. The half-pipe construction makes a strong jacket capable of withstanding pressure better than the conventional jacket design. 

For gases and vapors, typical fluid velocities are in the range of 15 to 30 m s-1. The fluid velocity must take account of standard pipe sizes. Table 13.7 gives details of a number of commonly used pipe sizes. 

Here, IDin is the internal diameter (in inches) of the pipe that contains the fitting. This method is valid over a much wider range of Reynolds numbers than the other methods. However, the effect of pipe size (e.g., 1 /IDin) in Eq. (7-37) does not accurately refect observations, as discussed below. 

Submersible turbine pumps are a variety of vertical turbine pumps with the motor attached below the pumping unit. Water passes in through an intake port located between the motor and bowl assembly, then upward through the bowl stages to the surface through the pump pipe. Electric power is supplied to the motor by specially insulated wires. Submersible turbine pumps are manufactured for water supply and oil well usage by a wide variety of manufactures in sizes ranging from /3 to several hundred horsepower, and are constructed of materials suited for many chemicals. 

In theory, there are an infinite number of leak sizes, ranging from a tiny pinhole to a full rupture of piping or equipment. It is clearly impractical to investigate them all. Thus, some practical guidance is necessary in selecting leak sizes that will allow a reasonable range of fire scenarios to be evaluated. 

In a chemical plant the capital investment in process piping is in the range of 25-40% of the total plant investment, and the power consumption for pumping, which depends on the line size, is a substantial fraction of the total cost of utilities. Accordingly, economic optimization of pipe size is a necessary aspect of plant design. As the diameter of a line increases, its cost goes up but is accompanied by decreases in consumption of utilities and costs of pumps and drivers because of reduced friction. Somewhere there is an optimum balance between operating cost and annual capital cost. 

The size of orifice-type flow sensors is limited only by the pipe size they are installed in, and their pressure and temperature ratings depend only on the limitations of the d/p detector used. Their measurement error is the combined orifice and d/p readout error, which in a standard installation over a 3 1 range is about 2% FS, and with an intelligent and multirange transmitter it can be reduced to 1% AF over a 10 1 range. 

Orifice Type Appropriate Process Fluid Reynolds Number Range Normal Pipe Size, in. (mm)... 

In a typical process, a transducer (transmit and receive) is mounted on a stainless steel pipe. Whilst the mechanical aspects of the construction of such systems are quite straightforward there is a very wide range of pipe sizes in a plant that requires monitoring. As an example, a system designed for use in a margarine plant is shown in Figure 21.2. Manufacturers of commercial equipment for ultrasound charaterization of dairy lipids are listed in Table 21.1. 

Pyrolysis vessels can range from 3 to 20 m in volume. Towards the upper end of the size range, heat transfer limitations occur and it is necessary to use heat exchanging pipes internally to assist with heat transfer. The problem with an array of heat exchanging pipes internally however is that they are susceptible to fouling and coking by a carbonaceous residue. 

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