Line pressure

Feed systems utilizing gravity are rarely used. Line pressure is usuaHy adequate for smaH systems. AuxHiary pumps are required in larger systems to assure proper flow through aH units and to avoid uneven flow should line pressure decrease as other demands for water or the process stream occur elsewhere in the facHity. 

Sulfurchlorination of unsaturated compounds or mercaptans is normally carried out at atmospheric pressure in a glass-lined reaction vessel because of the potential to Hberate HCl during the reaction. The sulfurchlorination vessel is equipped with a cooling jacket or coils (very exothermic reaction), a nitrogen or dry air sparging system, an overhead condenser, and a caustic or bleach scmbber. If one of the reactants (olefin or mercaptan) is alow boiling material, ie, isobutylene, a glass-lined pressure vessel is recommended. 

A pressure-reducing v ve in a line leading to a pressure vessel is not adequate protection against overpressure. Its f ure will subject the vessel to full line pressure. 

Where the TDS in water supphes is above the taste threshold, or where there is concern about the safety of the water supply, simple RO systems operating on line pressure have made a major impact. These compac t units are usually kitchen installed, and are simple, small, and cheap. For typical line pressure of 400 kPa, 95 percent reduction of TDS is feasible if the inlet concentration is below 2000 mg/ . 

Because the value of Z for natural gas is significantly less than unity at ambient temperatures and at pressures greater than 1 MPa (145 psia), the compressibility must be taken into account in gas measurement gas purchased at high line pressure will fflve a greater volume when the pressure is reduced than it would if the gas were ideal. Natural gas pipeline operators use a.. supercompre.s.sihility faclor, also called Z, out defined as... 

The nitrogen line pressure is set to a level much less than the experimental pressure. With the nitrogen cylinder open, a check valve prevents the feed gas from getting into the nitrogen cylinder. When the surge check valve cuts off the synthesis gas feed, the unit becomes depressurized. Then pressure drops below the nitrogen pressure level, nitrogen flow will start and flush out the system. 

Vibration values in mils, displaeement, veloeity, and aeeeleration. Observe all meters, guages, sight glasses, oil temperatures, diseharge temperatures, balanee-line pressures, surfaee eondenser temperature, ete. 

AP = Line pressure drop, psi P], P2 = Upstream and downstream pressures in psi ABS S = Specific gravity of vapor relative to water = 0.00150 MP,/T d = Pipe diameter in inches Ui = Upstream velocity, ft/sec f = Friction factor (assume. 005 for approximate work)... 

L = line length, miles Z = average gas compressibility D = pipe inside diameter, in. h2 = elevation at terminus of line, ft h = elevation at origin of line, ft Pa, = average line pressure, psia E = efficiency factor... 

It is easy to improperly design a steam trap. The design must work for two circumstances and often a designer will check only one of these. The circumstance often overlooked is as follows On startup or upset the steam control valve can open wide so that the steam chest (assume for this discussion that we are speaking of a reboiler) pressure rises to full steam line pressure. At a... 

When an installation is being planned, it is recommended that the API Standard 618 be reviewed in detail. The pulsation level for API 618 at Design Approach 1, the outlet side of any pulsation control device regardless of type, should be no larger than 2% peak-to-peak of the line pressure, or the value given by the following equation, whichever is less... 

If the calculated blending time is longer than desired, nozzle discharge flow rate can be increased or, nozzle diameter increased. Consideration of nozzle recirculation line pressure drops and pump characteristics is required to select the parameter to change. 

Kept open by line pressure when flow control valve is fully open. 

Vent and purge lines Procedure to indicate how to check if fully purged Ensure training covers symptoms of pressure in line Line pressure indicator at controls. Interlock device on line pressure. 

B. Direct Injection of Steam, Air, Methane, Cooling Water, etc. Supply line pressure plus 5 psi to 15 psi. 

For quick estimates for air line pressure drop, see Tables 2-12A and 2-12B. 

If sonic velocity of step 2 is greater than calculated velocity of step 1, calculate line pressure drop using usual flow equations. If these velocities are equal, then the pressure drop calculated will be the maximum for the line, using usual flow equations. If sonic velocity is less than the velocity of step 1, reassume line size and repeat calculations. 

L. = latent heat of evaporation at return line pressure, Btu/lb... 

Figure 4-78. Tubular in-line pressure filter with reusable elements. The flow unfiltered liquid enters the inlet port, flows upward, around, and through the media, which is a stainless steel or fabric screen reinforced by a perforated stainless steel backing. Filtered liquid disch lrges through the outlet (top) port. Because of outside-to-lnside flow path, solids collect on the outside of the element so screens are easy to clean. By permission, Ronningen-Petter Engineered Filter Systems, Bulletin RP-2.

Scope, 52 Basis, 52 Compressible Flow Vapors and Gases, 54 Factors of Safety for Design Basis, 56 Pipe, Fittings, and Valves, 56 Pipe, 56 Usual Industry Pipe Sizes and Classes Practice, 59 Total Line Pressure Drop, 64 Background Information, 64 Reynolds Number, R,. (Sometimes used Nr ), 67 Friction Factor, f, 68 Pipe—Relative Roughness, 68 Pressure Drop in Fittings, Valves, Connections Incompressible Fluid, 71 Common Denominator for Use of K Factors in a System of Varying Sizes of Internal Dimensions, 72 Validity of K Values,... 

Inlet nozzles should be sized for 2.5 gpm liquid per tube with the inlet line pressure drop not to exceed 1.5 psi per 100 equivalent ft of inlet piping for total gpm. Nozzles may, in all cases, come into the side of the bottom channel. 

In many instances, the design of suction and discharge pulsation dampening drums (or bottles) for reciprocating compressors is based on piston displacement and volumetric efficiency, and this design normally will suffice to reduce peak pulsation to approximately 5% of the line pressure. In special or other cases, experience has shown that operational difficulties (vibrations, meter pulsations, etc.) may indicate that the peak pulse pressure of 5% line pressure is inadequate. Thus, the pressure in pulsation-reduction design selection is... 

Figure by surge bottle method allowing peak pulse pressure to be 5% of the line pressure (P /P) = 1.05. Make both bottles the same size. 

P = absolute pressure, psia, at flowing gas conditions, or = may be operating pressure, psia Pl = line pressure, psi abs... 

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