Recommended velocities

Here are various recommended flows, velocities, and pressure drops for various piping services. 

Sizing Cooling Water Piping in New Plants Maximum Allowable Flow, Velocity and Pressure Drop 

Light Volatile Liquid Near Bubble 0.5 ft head total 

Absolute Pressure absolute pressure tor friction loss 

Vapor Lines General Max. velocity 0.3 mach 0.5 psi/IOOft 

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Maximum Recommended Velocities Through Nozzle Connections, Piping, etc. Associated With Sheil and/or Tube Sides of Heat Exchanger... 

Piping systems should be designed for an economic flow velocity. For relatively clean fluids, a recommended velocity range where minimum corrosion can be expected is 2 to 10 fps. If piping bores exist, maximum fluid velocities may have a mean velocity of 3 fps for a 3/8-in. bore to 10 fps for an 8-in.-diameter bore. Higher flow velocities are not uncommon in situations that require uniform, constant oxygen supply to form protective films on active/passive metals. 

Other empirical relations for ideal gas are given in Baum (1987) recommended velocities are upper limits. In each of these relations, a parameter F has been applied. 

VgiiQw = 12.2 recommended velocity of solvent and feed combined... 

Mesh manufacturers recommend an Rd of 1.54 (manufacturers k divided by 0.227) for all usual process applications. They report excellent performance from 30% Rd = 0.46) to 110% Rd = 1.69) of their recommended velocity. To allow for pressure surges, they suggest an Rd of 1.15 (75% of recommended velocity). 

The number of jets is based on gas velocity. For 1-inch standard pipe, the recommended velocity permits a flow rate of 61,200 scfd per jet. Expressed as an equation... 

Recommended velocity ranges for various services are given beiow ... 

Flow velocities play an important part in seawater corrosion. Velocity-dependent erosion corrosion is often associated with turbulance and entrained particles. Recommended velocities for continuous service are as follows ... 

Recommended velocity applies only to rich DEA flowing through the tubeside of a lean/rich exchanger. Dailey (1970) and Smith and Younger (1972) rqport Aat severe corrosion occurred in the tubes of a lean/rich exchanger when the tubeside velocity exceeded 5.25 ft/sec. 

Protection using low turbulence air flow permits germ-free air to move on parallel streamlines. The recommended velocity for vertical flow is 0.3 m/s, with 0.45 m/s recommended for horizontal flow. This is equivalent to an air flow rate of 1000-1500m / hr per m of room area - very much higher than typical air-conditioning systems. 

Example 15.3-1 Alternative plots of breakthrough curves Y ou are planning a series of test experiments using a new adsorbent. You hope to use this adsorbent at a commercial scale, and so plan to let many process variables vary widely. In particular, you plan to determine breakthrough curves at the manufacturer s recommended velocity and at twice this velocity. (a) If the breakthrough curves at different velocities are ideal, without dispersion, what will they look like when plotted vs. time (b) What will they look like plotted vs. number of bed volumes (c) How will they change if the breakthrough curves do show dispersion ... 

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