Power consumption evaluation

In the previous problem, it is desired to treat 12 m /hr of wastewater containing 1 wt/wt% urea. The osmotic pressure of the feed is 7 atm. The power consumption of the system is esdmated to be 5.0 kWh/m of permeate. Maintenance, pretreatment, and operating cost (excluding power) is S0.2/m of permeate. The annualized fixed cost of die system may be evaluated through the following expression ... 

The cost evaluation must include the recurring costs, such as power consumption, maintenance, etc. that are... 

The prediction of power consumption for agitation of a given non-Newtonian fluid in a particular mixer, at a desired impeller speed, may be evaluated by the following procedure. 

Biichs J, Zoels B (1999) Evaluation of the Maximiun Specific Power Consumption in Shaking Bioreactors, Proceedings of 3th International Symposium on Mixing in Industrial Processes (ISMlP-3) 19-22 Sept 1999 Japan... 

In the above example, the process characteristics (here, power characteristics) presenting a comprehensive description of the process were evaluated. This often expensive and time-consuming method is certainly not necessary if one has to only scale-up a given process condition from the model to the industrial plant (or vice versa). With the last example and the assumption that the Ne (0 characteristics like those in Figure 3 are not explicitely known, the task is to predict the power consumption of a Rushton turbine of rotating with = 200/min. The air throughput be = 500m /hr and the material system is water/air. 

EVALUATION OF POWER CONSUMPTION AND DISCUSSIONS RELATED TO APPLICATION... 

For transport of a gas-solid suspension, it is important to be able to evaluate the pressure drop in order to estimate the power consumption. In a pneumatic conveying system, particles are usually fed into the carrying gas and accelerated by the gas flow. The power consumption (or pressure drop per unit pipe length) for the acceleration of particles can be significant compared with that for a fully developed flow condition. Moreover, the pressure... 

They found that optimal conditions of the position of the stirrer exist in the range of 0.25 < HJd < 0.75 for both turbine and propeller stirrers. Their work suggests that beyond a Reynolds number of 20,000, the power number becomes constant. An increase in solid content increases the power consumption, while an increase in gas velocity reduces the power consumption. Kurten and Zehner (1979) examined the effect of gas velocity on the power consumption for suspension of solids and found that because of simultaneous aeration, a higher power input is required for suspension in the presence of gas. This is mainly due to the reduced liquid circulation velocity in the presence of gas bubbles. Most recently, Albal et al. (1983) evaluated the effect of liquid properties on power consumption for both two- and three-phase systems. They found that power consumption per unit volume increases with solid concentration. The influence of particle size on power consumption increases with the solids concentration. For an unconventional arrangement of a stirrer, they also found different Ne-Re curves for glycerine and CMC solutions. 

Geraldes and de Pinho [37] modeled NF permeate using a prepared salt solution to evaluate the feasibility of ED for the removal of chloride ions. The modeled permeates contained chloride ions from 1650 to 2250 mg/L depending on the water recovery. In that study, the quality requirements for the washing waters for pulp bleaching were 350 mg/L of NaCl and 30 PtCo units of color. The NF followed by ED met these requirements and the evaluated costs were 0.65 per m at 80% water recovery. Rapp et al. [131] reported the electrical power consumption of ED to be 0.97 kW h/kg chloride removed. 

Rate of impeller rotation could be used as some indication of the work being done on the material. As the motor or impeller power consumption is proportional to the product of torque and speed, the latter is an important factor in evaluating the corresponding load. 

Several attempts were made to evaluate the use of FBRM particle size analyzer as a potential tool for granulation end-point determination. Dilworth et al.f have compared power consumption, FBRM, and acoustic signals in a study of a wet granulation process in Fielder PMA 200 mixer. It was found that these techniques were complimentary, with FBRM probe capable to follow median granule size growth even when the power consumption curve showed a plateau. 

Bertrand J., Couderc J.P., Evaluation of the power consumption in agitation of viscous Newtonian or pseudoplastic liquids by two-bladed, anchor or gate agitators, Chem. Eng. Res. Dev. 63 (1985) 7, p. 259-263... 

The effect of fluid rheology on the power consumption of helical ribbon agitators has also been evaluated [54] and power consumption as a function of generalized Reynolds number for shear thinning but inelastic fluids defined. When shear thinning effects are small, and elasticity is negligible, deviations from the Newtonian... 

The available energy consumption represented by the pressure drop was 92 kW (123 hp). These results not only illuminated the impact of the pressure drop on power consumption but also enabled the associated capital and operating cost implications to be quickly and straightforwardly evaluated. 

Electrochemical reactor design is ideally a good compromise between capital and power costs. The power consumption of a cell or reactor is the most important single factor needed to evaluate its performance. Both the powar production and chemical process industries, (CPI), involve heat and electrical energy in a similar fundamental way, and so are governed by the second law of thermodynamics. The second law actually imposes an absolute natural limitation on the efficiency of any energy transformation, and therefore it provides a reliable standard with which to compare and control practical operations (30) (31) (32). 

Other reactions evaluated by the authors included Wittig-Horner olefination and a series of ring-closing metathesis (RCM) reactions, employing Grubb s II catalyst. In all cases, a reduction in power consumption, increase in yield, and reduction in reaction time were obtained as a result of employing microwave-assisted continuous flow reactions [33],... 

In some reports, steam drying is claimed to reduce power consumption for milling as the grindability index is increased due to steam drying. At elevated degrees of superheat and prolonged exposure times, some studies have reported a reduction in the sulfur content of coal. This is not necessarily an advantage as the sulfur will then enter the dryer-exhaust steam. Additional data are needed to evaluate this aspect in detail. 

The power required for movement can be considered approximately equal to 15 % of the cutoff. The knowledge of the maximum power consumption is useful for the selection of cutting parameters based on the machine on which you are working, while the average value is useful for evaluation of power consumption and thus the cost of processing. 

---