Line sizing

Normally no flow, design only, for line sizing based on 60% water cut at SOOOm /d... 

Line size and length must be small enough to meet transporttime requirements without excessive pressure drop or excessive bypass of sample at the analyzer input. 

Line size and internal-surface quality must be adequate to prevent clogging by the contaminants in the sample. 

The velocities are suggestive only and are to be used to approximate line size as a starting point for pressure drop calculations. 

The final line size should be such as to give an economical balance between pressure drop and reasonable velocity. 

Values listed are guides, and final line sizes and flow velocities must be determined by appropriate calculations to suit circumstances. Vacuum lines are not included in the table, but usually tolerate higher velocities. High vacuum conditions require careful pressure drop evaluation. 

To rough out line sizes and pressure drop for fan or blower sizing, use the following, quickie method ... 

Reboiler return line sized too small. Poor separation limited capacity. Unstable operation. Expansion design error. 

Downstream line size 400 mm and greater mass flow rate greater than 91,000 Kg/hr or pressure ratio greater than 3. 

Downstream line size 200-350 mum downstream line velocity greater than 50% sonic and pressure ratio greater than 5. 

A trial and error estimate is made for determining the diameter of the flare header based upon the maximum relieving flare load and considering the back pressure limitation of 10 percent for conventional valves and 40 percent for balanced type valves. Note, however, a single main header in most cases turns out to be too large to be economically feasible. Line sizing procedures are discussed in detail in the next subsection. 

The subheaders in each process area similarly will have two levels of flare headers. The line sizing of each level of subheader in an individual area will depend upon the maximum simultaneous flow in that particular area. Thus the line sizing criterion of a subheader may be the largest single flow due to a blocked outlet condition. This flow may not necessarily be the controlling load for the flare stack. 

When the maximum vapor-relieving requirement of the flare system has been established and the maximum allowable back pressure (as just described) has been defined, line sizing reduces to standard flow calculations. 

Although Figures 19 and 20 can be used for line sizing, it should be noted that Figure 19 requires more extensive trial and error calculations. 

But the outlet nozzle size of the safety valve is 6 in. Schedule 40. Hence, 6 in., will be minimum line size. (This is normal practice.)... 

It is evident that most studies reported to date have used number density, average size or weight per eent as eontrol variables. Often these variables are inferred from other measurements, ineluding density, solution supersaturation, refraetive index ete. Inferential teehniques have been shown to be partieularly suitable for industrial seale applieations where laser seattering deviees for on-line size distribution measurement are not yet praetieal for industrial eontrol purposes, although substantial progress is being made to that end. Even when usable, however, these measurement deviees are often eharaeterized by noise and require operation at very low solids eoneentration. 

When the relieving scenarios are defined, assume line sizes, and calculate pressure drop from the vent tip back to each relief valve to assure that the back-pressure is less than or equal to allowable for each scenario. The velocities in the relief piping should be limited to 500 ft/sec, on the high pressure system and 200 ft/sec on the low pressure system. Avoid sonic flow in the relief header because small calculation errors can lead to large pressure drop errors. Velocity at the vent or flare outlet should be between 500 ft/sec and MACH 1 to ensure good dispersion. Sonic velocity is acceptable at the vent tip and may be chosen to impose back-pressure on (he vent scrubber. 

The various items of equipment in the production facility are connected hy valves, fittings, and piping to enable and control flow from one piece of equipment to another. Chapter 9 of Volume 1 discusses factors governing the choice of line size and wall thickness. This chapter describes the various types of valves and fittings commonly used in production facilities and presents some common piping details and specifications. 

Lapp, K. and Vickers, K. 1992. Detonation Flame Arresters and Larger Line Sizes. International Data Exchange Symposium on Flame Arresters and Arrestment Technology. Banff, Alberta (October 1992). 

K. Grob and R Kalin, Attempt foi an on-line size exclusion clnomatography method for analyzing pesticide residues in foods , 7. Agric. Food Chem. 39 1950-1953(1991). 

M. De Paoli, M. Barbina Taccheo, R. Mondini, A. Pezzoni and A. Valentino, Determination of organophosphoms pesticides in fruits by on-line size-exclusion chi O-matography-flame photometric detection , 7. Chromatogr. 626 145-151 (1992). 

The usual complete line designation contains the following (1) line size (nominal) (2) material code (3) sequence number and (4) materials of construction. 

Na Moteriol From To Line Size Oper. Temp. "F Oper. Press, Test Pres. Ouonitv Vel. F.RS. Press. Drop Remorks No. 

Flow rate and length kno Ti, determine pressure drop and line size. 

Usually either of these conditions requires a trial approach based upon assumed pipe sizes to meet the stated conditions. Some design problems may require determination of maximum flow for a fixed line size and length however, this just becomes the reverse of the conditions above. 

Overflow pump suction lines are designed for about a one foot/second velocity, unless a higher velocity is necessary to keep small solids or precipitates in suspension. Suction line sizes should be larger than discharge sizes. 

Note when used for pump system balance, this Zhf must be used as a negative number ( — 0.1863) because it is a pressure loss associated with the fluid flowing. For pipe line sizing, the pressure head on the tank of 5 psig and any elevation difference between tank outlet nozzle and pump suction centerline do not enter into the calculations. 

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