Specific drive power

Measuring the drive power enables us to identify the specific energy input e=drive power/ throughput, which is also known as the specific drive power. This is a characteristic value for many processes and is also used for comparisons [1]. 

The discussion of the specific drive power in the previous section clearly shows that improved quality does not necessarily come at the expense of increased energy input. This is due to improved design of each zone for the task at hand. With the optimum speed at each stage, only the energy required for the process is introduced into the product. 

The process engineering tasks are classified according to the product groups for which they are used. There are four main areas material mixing, material separation, reaction, and phase transformation. The common factor of all the processes in Table 2.1 is of course the high-viscosity phase and consequendy the specific difficulties of the machinery (technical design, dimensioning with respect to forces, torques, drive power, pressures). 

An enthalpy diagram also shows that the temperature increase in the example shown is directly linked to the specific energy input. Figure 6.6 gives the specific enthalpies for different products and converts them from kj/kg (left) to kWh/kg (right). In this example, the drive power of the extruder is converted into the dissipative product heat increase . 

The specific heating and cooling power is an often-underestimated source of error. It is physically possible for a large production extruder to require less heating and/or cooling power than a small laboratory extruder in terms of drive power (Fig. 11.15). Therefore, laboratory extruders are often operated adiabatically or only moderately heated in order to ensure comparability with a large extruder. 

The EV power requirements depend on the car s end use and assumed acceleration demands. For example, the specifications for safe driving in a mixed ICEV and EV urban traffic of a small compact-type EV have been defined as acceleration from 0 to 50 mph in <20 s. The specific peak-power corresponding to these demands has been calculated as 80-90 wkg for conditions of optimum use of the AC power train (i.e., for constant-power acceleration following the initial period in which the peak-power is attained at the maximum tractive effort ). The majority of near-term and advanced batteries could, at least potentially, meet these demands. 

More equations can be found in the literature [e.g. B.8, B.12b, B.42, B.47, B.56]. If the specific force, the average density of the product, and the desired throughput capacity of the machine are known, with the sheet thickness or the briquette size a roller size can be calculated and a machine can be selected based on its maximum specific force capability. The drive power is determined from the torque requirement during testing and safety factors are added to all machine and process parameters. After installation it is normally necessary to readjust and optimize all conditions in-line. 

Those battery systems allowed typically a range of up to 160 km under specific driving conditions but long charge times of 8-10 h, due the 3.3 kW restricted power level of typical German 230 V single-phase outlets, demonstrated that BEVs at the time were not a full replacement for vehicles with ICEs which can be refueled within minutes. 

An overview of feeder design and performance with specific reference to belt and apron feeders is presented. The interfaee geometry of the feed zone is examined in relation to the requirements for the optimum draw-down pattern in the hopper. Relevant aspects of feeder load and drive power determination is reviewed and the need for controlling feeder loads is stressed. The influence of hopper and feeder interface with respect to the shear resistance and feeder slip is outlined. 

This reaction has been carried out with a carbon dioxide laser line tuned to the wavelength of 10.61 p.m, which corresponds to the spacing of the lowest few states of the SF ladder. The laser is a high power TEA laser with pulse duration around 100 ns, so that there is no time for energy transfer by coUisions. This example shows the potential for breakup of individual molecules by a tuned laser. As with other laser chemistry, there is interest in driving the dissociation reaction in selected directions, to produce breakup in specific controllable reaction channels. 

Power to drive a belt conveyor is made up of five components power to drive the empty belt, to move the load against fric tion of the rotating parts, to raise or lower the load, to overcome inertia in putting material into motion, and to operate a belt-driven tripper if required. As with most other conveyor problems, if is advisable to work with formulas and constants from a specific manufacturer in making these calculations. For estimating purposes, typical data are given in Table 21-7. 

The petroleum industry is one of the largest users of gas turbines as prime movers for drives of mechanical equipment and also for power generation equipment. Thus the specifications written are well suited for this industry, and the tips of operation and maintenance apply for all industries. This section deals with some of the applicable API and ASME standards for the gas turbine and other various associated pieces. 

Electric motors are the most common drivers for the m ority of pumps, compressors, agitators, and similar equipment in the process industries. Process engineers should obtain the assistance of a qualified electrical engineer before completing motor specifications ior the wide variety of equipment applications and respective power sources. The use of standard specifications for the various types and classes of motors is helpful and reduces repetitious details. Be certain that the type of motor is properly matched to the service, atmosphere, load characteristics, and available type and power factor of the electrical energy to drive the motor. Some basic guides are summarized, but they cannot be used as all-inclusive rules to fit all plant or equipment condi-... 

Several common arrangements have been developed to improve the efficiency and/or to accomplish specific purposes, such as furnishing hot flue gas to boilers or to process gas exchangers in addition to the simultaneous generation of power or driving equipment. Figures 14-37A-D illustrate several common arrangements or cycles. 

Figure 14-41. Performance specifications for one manufacturer s gas turbine generators that drive the power turbine unit for mechanical and power applications. (Used by permission Bui. 6-204B. Cooper Cameron Corporation, Cooper Rolls Division.)...

Ratio of gassed to ungassed power, PJP = 0.4 Driving force for OTR = 6 X 10 3kg/m3 Specific 02 uptake = 0.65 mmol 02/kg cell Also, the kinetic data are given as vmax = 0.5 h-1 Specific sugar consumption rate of cells = l.Okg/kg cell-h... 

The purpose of a centrifugal pump is to increase the pressure of a liquid in order to move it through a piping system. The pump is driven by a motor, which must provide sufficient power to operate the pump at the desired conditions. You wish to find the pressure developed by a pump operating at a flow rate of 300 gpm with an oil having a specific gravity (SG) of 0.8 and a viscosity of 20 cP, and the required horsepower for the motor to drive the pump. The pump has an impeller diameter of 10 in., and the motor runs at 1200 rpm. 

A coal suspension is found to behave as a power law fluid, with a flow index of 0.4, a specific gravity of 1.5, and an apparent viscosity of 90 cP at a shear rate of 100s 1. What would the volumetric flow rate of this suspension be in a 15 ft long, 5/8 in. ID smooth tube, with a driving force of 60 psi across the tube What is the Reynolds number for the flow under these conditions ... 

---