Pump Process

The seal tank receiving the water from the reactor section and the sump tank receiving the process water from the flash evaporators are enclosed in this building for shielding and instrument main.tenance reasons. The equipment is located on seven main levels so as to obtain building compactness and to achieve proper hydrostatic balance between the seal-tank level, suction lift to the flash evaporators, and barometric discharge to the sump tank. 

All piping and pumps are shielded with about 1 ft of concrete, and the valve control handles are extended through the shielding. All instrumentation and controls for maintaining proper process-water temperatures and flows are centralized in the Process Water Building instrument room. Overhead cranes and removable floor slabs provide accessibility- to shielded pipes, valves, pumps, etc. Each pump cubicle is shielded from it neighboring cubicle so that repairs can be made during reactor operation. 

1 Sump Tank. The sump tank has a capacity of 100,000 gal. The primary functions of the sump tank are to receive the process water from the flash evaporators and to supply it to the process-water pumps. The tank normally contains a 3-min holdup of about 60,000 gal. This holdup is necessary for satisfactory operation of the process-water pumps. The additional 40,000 gal capacity of the tank provides for the accumulation of water in the event of failure of the process—water pumps. The sump tank also receives process water via an overflow from the seal tank. 

2 ProeeSB Pumps. Three 10,000-gpm 225-ft-head horizontal single-stage double-suction centrifugal pumps, each driven by a 700-hp motor, are 

motors included, normally represent 5-10% of the total major equipment cost for new plant construction. They represent a much larger share of the total cost for electrical hardware and power wiring and this cost is usually several times that of the equipment cost for pumps and drivers. Pumps are significant consumers of process energy. 

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For quick pump selec tion, manufacturers often give the most essential performance details for a whole range of pump sizes. Figure 10-30 shows typical performance data for a range of process pumps based on suction and discharge pipes and impeller diameters. The performance data consists of pump flow rate and head. Once a pump... 

Vertical Pumps In the chemical industiy, the term vertical process pump (Fig. 10-40) generally applies to a pump with a vertical shaft having a length from drive end to impeller of approximately 1 m (3.1 ft) minimum to 20 m (66 ft) or more. Vertical pumps are used as either wet-pit pumps (immersed) or dry-pit pumps (externally mounted) in conjunction with stationaiy or mobile tanlcj... 

FIG. 10-40 Vertical process pump for dry-pit mounting. Coutiesif of Lawrence Pumps, Inc.)... 

Sump Pumps These are small single-stage vertical pumps used to drain shahowpits or sumps. They are of the same general construction as vertical process pumps but are not designed for severe operating conditions. 

In important process pumps, the grease in a bearing should be changed every 12 to 18 months. This will a,ssure a reliable pump operation and service because time alone causes certain deterioration in the lubricating ability of grea.se. 

A paper mill was using an ANSI end suction process pump with clear water service. The motor was designed properly. The pump axial thrust bearing ran hot, failing after three months of operation. It was replaced with an identical bearing. This ran during three months and also failed. All pump components were investigated and found that they complied with the specifications. These facts eliminated the defects of materials as a cause. 

This chapter presents information on rating, sizing, and specifying process pumps. The emphasis will be on centrifugal pumps, which are by far the most widely used in the process industries however, applications of other types of pumps will also be discussed (see Table 3-1). 

Figure 3-12. Single-stage, high speed (>5000 ft) centrifugal process pump. Pumps are high speed, gear driven, and especially suited for applications in light hydrocarbon liquid service. (Courtesy Sundstrand Fluid Handling, Inc.)...

The effects of impeller shape for the usual centrifugal process pump performance are given in Figure 3-34. The only part the process designer can play is in the selection... 

For many process pumps the LIO life is less than 8000 hours, so they usually fall in Classes 4, 5, and 6. A typical system use a running pump rated at 100 per cent... 

Davidson, J. (ed.). Process Pump Selection-A Systems Approach, I. Mech. E., London (1986). 

As an example of the importance of process parameters monitoring, consider a process pump that may be critical to plant operation. Vibration-based predictive maintenance will provide the mechanical condition of the pump and infrared imaging will provide the condition of the electric motor and bearings. Neither provides any indication of the operating efficiency of the pump. Therefore, the pump can be operating at less than 50 per cent efficiency and the predictive maintenance program would not detect the problem. 

Based on rough vacuum process pumps. Use 25 ft/s for high vacuum pumps. 

DAVIDSON, J. and VON Bertele, O. (1999) Process Pump Selection—A Systems Approach (I. Mech E.)... 

IChemE (1988) A New Guide to Capital Cost Estimation 3rd edn (Institution of Chemical Engineers, London). JACOBS, J. K. (1965) Hydrocarbon Proc. 44 (June) 122. How to select and specify process pumps. 

Source Jacobs, J.K. How to Select and Specify Process Pumps, Hydrocarbon Processing, June 1965, p. 122. 

The logic of the evolution of insertion can now be considered. Much as the most primitive selectivity of the chemistry of the uptake process, pumping, carrying and final binding to form a useful enzyme is not an invention by organisms but is a necessary consequence of inevitable equilibrium considerations (see Section 4.17), so the binding of particular metal ions to particular chelatase proteins was similarly selected... 

Five process pumps are lined up in a row and numbered as shown in Figure 10-17. Can you identify the hazard A similar layout led to a serious accident by a maintenance... 

A hot oil distillation system was being prepared for operation. The temperature was gradually raised to 500°F. A valve at the bottom of the tower was opened to initiate the transfer of heavy hot oil to a process pump. 

Localized failures of pressurized piping, process pumps, vessels or other parts of the process under pressure will cause a "torch" or "jet" fire. These fires may project flames in any direction, for a considerable distance, depending on the contained pressures and volumes of the source. Any facility that retains large amounts of high pressure liquids or gases can produce jet for extended periods if adequate isolation and depressurization capability is unavailable. The worst offenders in these cases are wellheads, high pressure gas pipelines and storage facilities. 

Linings of components used in chemical processing, pump housings, compressor linings and components. .. 

For an overhung end suction process pump, the nozzle sizes and location coordinates are as given in Table F-IA. The applied nozzle loadings are as given in Table F-2A. The problem is to determine whether the conditions specified in F. 1.2.1, F. 1.2.2, and F. 1.2.3 are satisfied. 

Some common enclosures are small buildings or enclosures for utility air or process gas compressors, gas turbines, refrigeration compressors, process pumps, filters, additive systems, dust collectors, field instruments, etc. 

The actual finite-time Rankine cycle is shown in Fig. 7.17. The cycle is an external and internal irreversible cycle that consists of two irreversible internal adiabatic processes (pump and turbine) and two irreversible external isobaric heat-transfer processes. The heat source and heat sink are... 

M Measuring and switching device PP Process pump RC Reference chamber PC Process chamber AP Auxiliary pump... 

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