Delivery pressure

Relief systems are expensive and introduce considerable environmental problems. Sometimes it is possibly to dispense with relief valves and all that comes after them by using stronger vessels, strong enough to withstand the highest pressures that can be reached. For example, if the vessel can withstand the pump delivery pressure, then a relief valve for overpressurization by the pump may not be needed. However, there may still be a need for a small relief device to guard against overpressurization in the event of a fire. It may be possible to avoid the need for a relief valve on a distillation column... 

From the above plot, it can be seen that the recovery factor for gas reservoirs depends upon how low an abandonment pressure can be achieved. To produce at a specified delivery pressure, the reservoir pressure has to overcome a series of pressure drops the drawdown pressure (refer to Figure 9.2), and the pressure drops in the tubing, processing facility and export pipeline (refer to Figure 9.12). To improve recovery of gas, compression facilities are often provided on surface to boost the pressure to overcome the pressure drops in the export line and meet the delivery pressure specified. 

Fans are used for low pressures where generally the dehveiy pressure is less than 3.447 kPa (0.5 Ib/iu"), and blowers are used for higher pressures. However, they are usually below delivery pressures of 10.32 kPa (1.5 Ibfiin"). These units can either be centrifugal or the axial-flow type. 

For small flowrates, the single-casing radial compressor without intercooling is employed for delivery pressures of up to 4-6 bar. Higher pressures of up to 15 bar are attained with intercooled machines of single- and double-casing design. 

Where inerting is not used, one guideline restricts operations to metal or enameled metal tanks having a volume no greater than 5 m, a diameter no greater than 3 m and all conductive parts grounded. The liquid should contain a maximum of 1 wt% insoluble solids, have a maximum feed rate of 60 L/min and the delivery pressure should not exceed 50 bar. The vessel should be continuously drained to prevent liquid accumulation [127]. 

Fit approved cylinder pressure regulators, selected to give a maximum pressure on the reduced side commensurate with the required delivery pressure. (The regulator and all fittings upstream of it must be able to withstand at least the maximum cylinder pressure.)... 

When a fluid is flowing through a pipe, resistance to flow is caused by friction. The pipe bore selected for each section must be such that under any operating conditions, the initial head, either static head of oil in the supply tank or the pump delivery pressure, will be adequate to ensure the required flow rate. Additionally, any change of flow rate and consequent variation in loss of head must not adversely affect the operation of the associated oil-burning equipment. 

Since discrete quantities are trapped and transferred, the delivery pressure and flow varies, as shown in Figure 32.21, which also illustrates how increasing the number of cylinders in a reciprocating pump reduces fluctuations. In the case of lobe and gear pumps the fluctuations are minimized by speed of rotation and increasing tooth number, but where, for control or process reasons, the ripple in pressure is still excessive, means of damping pulsations has to be fitted. Often a damper to cope with this and pressure pulses due to valve closure is fitted, and two types are shown in Figure 32.22. 

For higher pressures, rotary compressors of the sliding vane type will give delivery pressures up to 1 MN/m2. In a compressor of this type, as illustrated in Figure 8.35, the compression ratio is achieved by eccentric mounting of the rotor which is slotted to take sliding vanes which sub-divide the crescent-shaped space between the rotor and... 

In the formulation of Bickel et al. (B7) which appears to be the most general formulation on this problem to date, both the feed and delivery conditions (temperature, pressure, flow rate, and composition) are specified. As before, the decision variables include the pipe diameters. But in addition, the number, placement, suction, and delivery pressures of compressors may also be varied within the constraints of overall pipeline lengths and network... 

In the formulation above, the discrete optimization on the number of compressors has been transformed into a continuous optimization on suction and delivery pressures. This transformation was made possible by the form of the compressor cost function which vanishes when pd = ps. However, if the compressor costs include a fixed capital outlay, i.e., the cost function is a linear function of horsepower with a nonzero constant term, then a branch and bound procedure must be used in conjunction with the GRG method. 

Maximum delivery pressure from storage systems atm (absolute) 100 100... 

Maximum delivery pressure Charging and discharging rates atm (abs) 100 100 100... 

Gas must be commercially free of sand, dust, gums, and free liquid. Delivery temperature, 322.16 K delivery pressure, 4.83 MPa. Ref. 8. b ASTM = American Society for Testing Materials GPA = Gas Processors Association. 

NFPA 57 recommends that LNG dispensers be protected from collisions with vehicles and that they incorporate an emergency shut-down system. The maximum delivery pressure of the dispenser shall not exceed the operating pressure of the LNG tanks on the vehicle being refueled, and the LNG delivery hoses must have a shut-off valve at the end and a breakaway valve in the event a vehicle drives off with the refueling hoses attached. Bleed and vent valve must be incorporated into the dispensing lines to allow them to be drained and depressurized prior to disconnection if necessary. 

The delivery pressures to SOCAR from the ACG Sangachal Terminal are considerably in excess of the presently available operational pressures in the Azerigas system to and from the Karadagh node. SOCAR has a contractual obligation to take gas from the ACG Sangachal Terminal and must have these gas receipt facilities available 3 months in advance of the start of Phase 1 oil production. Thus, the gas receipt facilities must be operational by the end of the third quarter of 2004 and this will become SOCAR project. 

More Pressure 6. Isolation valve is closed in error while pump running. Lines subject to full delivery pressure. Covered by b) f) Perhaps worthwhile installing a pressure gauge upstream of the delivery pump. 

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