Pumping unit

The disadvantages of this method ate the need for a torque meter, longer total length of the pumping unit, and greater susceptibiUty to misalignment and vibrations. This method is used only at a manufacturer s test faciUties or research laboratories. It is not used in the field. 

Metering Pumps. For small flow rates, such as dosing chemical additives where precise control is requited, progressive cavity self-contained pumping units are used. These can often handle shear-sensitive fluids or Hquids containing abrasive particles. These pumps are not as widely pubHci2ed or generally as well known in the Hterature as other pump types. 

Centrifugal pumps also rec]uire that the fluid be available to the pump s suction nozzle with sufficient energy. Centrifugal pumps cannot suck or draw the liquid into the pump housing. The principal pumping unit of a centrifugal pump is the volute and impeller. (See Figure 1-3). 

The tandem dual seal is mostly mated to a pressurized barrier tank, or a pumping unit as the support system. Support systems are discussed later in this chapter. 

To obtain the benefits of this seal, it is necessary to install a gauge indicating the actual seal chamber pressure. Sensors and transmitters can be used to monitor and act on a pressure change. One of the two seals can fail without product loss or fugitive emissions. This seal would be connected to a pumping unit seen later in this chapter. 

The piston plunger pump is the simplest form of a positive displacement pump. These pumps can be powered by a variety of prime movers, internal combustion engines, and electric motors (and in some cases, powered by a gas turbine motor). In such applications, the separate pump unit is connected to the prime mover by a power transmission. 

Most pump units comprise a receiver tank that conventionally is vented to atmosphere and one or more motorized pumps. It is important with these units to make sure that the maximum condensate temperature as specified by the manufacturer is not exceeded, as well as that the pump has sufficient capacity to handle the load. Condensate temperature usually presents no problem... 

Pump units, including valves, gages, etc., are classified as individual assets. To enable the asset number to signify the different process that the pump is serving, the Plant Code 05 is suffixed, e.g. ... 

With practical installations it must be remembered that the frictional losses cannot be estimated with very great accuracy because the roughness will change with use and the pumping unit must therefore always have ample excess capacity. 

The mass of air required to pump unit mass of liquid is, therefore, given by ... 

A petroleum fraction is pumped 2 km from a distillation plant to storage tanks through a mild steel pipeline, 150 mm in diameter, at the rate of 0.04 m3/s. What is the pressure drop along the pipe and the power supplied to the pumping unit if it has an efficiency of 50%)... 

This paper describes work on equipment and instrumentation aimed at a computer-assisted lab-scale resin prep, facility. The approach has been to focus on hardware modules which could be developed and used incrementally on route to system integration. Thus, a primary split of process parameters was made into heat transfer and temperature control, and mass transfer and agitation. In the first of these the paper reports work on a range of temperature measurement, indicators and control units. On the mass transfer side most attention has been on liquid delivery systems with a little work on stirrer drives. Following a general analysis of different pump types the paper describes a programmable micro-computer multi-pump unit and gives results of its use. 

Figure 7. Intelligent pumps unit Mkll in fume cupboard.

Outdoor air is treated and pre-conditioned by a central water-to-air heat pump. The outdoor air is delivered into the return air plenum of the zone heat pump units. A total enthalpy wheel can reduce the energy consumed for treating outdoor air. 

The energy (or first law) efficiency is simply a ratio of useful output energy to input energy and is referred to as a coefficient of performance (COP) for refrigeration systems. The energy efficiency of the heat pump unit can thus be defined as follows ... 

Table 16 describes the predicted performance of the GSHP system. Total amount of extracted heat from the ground reaches 180 GJ and electricity consumption is 13.9 MWh. In this time COP ofthe heat pump unit is 4.4. When this system will adopt a constant—speed pump which can cover the maximum heat output, SCOP is 2.7. This result suggests that a variable speed pump according to the heat loads is effective to improve SCOP. On the other hand, released heat into the ground during summer is 56 GJ and the electricity of 3.6 MWh is consumed to circulate the brine between U-tubes in the foundation piles and ventilation units. SCOP during summer is estimated to be 5.7. This can be also improved. 

Pumping unit Driver and coupling Base plate... 

The motor (usually working in vacuum) is moved by a special current power supply. The rotor turns at 104-105rpm, usually a multiple of the line frequency. The pumping speed of a turbo pump unit depends on its rotational speed. High-speed turbo pumps need more frequent maintenance interventions. In some turbo pumps, a low-speed mode allows operation up to 10 1 torr. However, full rotational speed is achieved at pressures... 

A cover plate on a pump housing is held in place by eight bolts. A pipe fitter is instructed to repair the pump. The fitter removes all eight bolts only to find the cover plate stuck on the housing. A screwdriver is used to pry off the cover. The cover flies off suddenly, and toxic liquid sprays throughout the work area. Clearly the pump unit should have been isolated, drained, and cleaned before repair. There is, however, a better procedure for removing the cover plate. What is this procedure ... 

The produced oil or gas is connected to surface flowlines from the wellhead pumping unit or surface regulating valve assembly typically referred to as a Christmas tree but to its arrangement. The flowlines collect the oil or gas to local tank batteries or central production facilities for primary oil, water, and gas separation. The reliability of electrical submersible pumps (ESPs) has increased to the point where the submersible electrical pump is commonly used for the production of liquid hydrocarbons where artificial lift is required for production. 

At sites where the fluid level (water or LNAPL) is below the suction-lift depth, the use of a down-hole pumping unit is necessary. When a single-pump system is used, the water and/or LNAPL is delivered to the surface for separation or treatment, as shown in Figure 7.12. Several types of single-pump systems are in common usage. 

Submersible turbine pumps are a variety of vertical turbine pumps with the motor attached below the pumping unit. Water passes in through an intake port located between the motor and bowl assembly, then upward through the bowl stages to the surface through the pump pipe. Electric power is supplied to the motor by specially insulated wires. Submersible turbine pumps are manufactured for water supply and oil well usage by a wide variety of manufactures in sizes ranging from /3 to several hundred horsepower, and are constructed of materials suited for many chemicals. 

Operation of a system on a continuing basis requires regular monitoring and maintenance. This phase represents the largest cost items of a long-term project however, routine adjustments of pumping units, coupled with preventative maintenance, will result in lower long-term costs. 

The pumping unit consisted of a submersible pump installed in a 10,000-gal reservoir tank, which also served as a holding tank (Figure 12.16). Fluids pumped from the wells were all returned to the tank for separation. All the oil and some water produced overflowed from the tank into another oil-water separator and then into the slop oil treatment system of the refinery. Clarified water from the bottom of the tank was recycled by the submersible pump through the eductor units to continue operations. 

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