Pumps costs

Any commercially available vacuum pump is perfectly fine for the underground chemist s needs but the best kind to buy is a diaphragm pump, which is more resistant to the often-harsh chemical vapors that are sucked through it. Most vacuum pumps cost about 100- 200. However, the stronger the vacuum the better. If a chemist is looking to pull 1mm of Hg (don t ask) like the girls in the chemistry papers do then she can be looking at a turbovac that can run well over 5000. 

Another large cost associated with incoming water is associated with its movement. Many aquaculture faciUties that utilize surface waters and those that obtain their water from wells other than artesian wells are required to pump the water into their faciUties. Pumping costs can be a major expense, particularly when the faciUty requires continuous inflow. 

Air coolers almost invariably add considerably to plant cost, but they are competitive in operating cost based on direct once-through use of water that requites no treatment. If the alternative to air coolers is the use of water that requites substantial treatment or pumping costs, the air coolers will cost less to operate. 

Tubercles are mounds of corrosion product and deposit that cap localized regions of metal loss. Tubercles can choke pipes, leading to diminished flow and increased pumping costs (Fig. 3.1). Tubercles form on steel and cast iron when surfaces are exposed to oxygenated waters. Soft waters with high bicarbonate alkalinity stimulate tubercle formation, as do high concentrations of sulfate, chloride, and other aggressive anions. 

Johnson, J. D., Wariable-Speed Drives Can Cut Pumping Costs, Chem. Eng., Aug. 10, 1981. 

Assess the cost factors applicable, in terms of fan, pump cost, price of land, maintenance and treatment costs. 

As with ED, RO, and other membrane techniques, the primary operational cost of EDR is that of pumping water through the system, and pumping costs are proportional to the TDS of the incoming water. Cost for the actual electrodialysis is low. 

The capital cost of a pipe run increases with diameter, whereas the pumping costs decrease with increasing diameter. The most economic pipe diameter will be the one which gives the lowest annual operating cost. Several authors have published formulae and nomographs for the estimation of the economic pipe diameter, Genereaux (1937), Peters and Timmerhaus (1968) (1991), Nolte (1978) and Capps (1995). Most apply to American practice and costs, but the method used by Peters and Timmerhaus has been modified to take account of UK prices (Anon, 1971). 

Equations for the optimum pipe diameter with laminar flow can be developed by using a suitable equation for pressure drop in the equation for pumping costs. 

Cost of instrumentation for control of recovery section Cost of electricity for pumps Pump costs (total)... 

DOE Report, 1981. Chemical heat pump cost-effectiveness Evaluation, BNL-51484, DE82-008858. 

Flow and recycle rates should not be high enough to cause excessive pumping costs or loss of hydraulic containment efficiency due to turbulent conditions, corrosion, flooding, or well blow out. 

All of these goals cannot be met. For example, to reduce potential losses in case of fire, the plant should be spread out, but this would also result in higher pumping costs, and might increase manpower needs. The engineer must decide within the guidelines set by his company which of the aforementioned items are most important. 

The values given by Guthrie are average values, and he notes that the actual cost may vary from this by as much as 35%. This range almost includes the other two values. For all futurecalculations, the pump costs determined from Guthrie s figures are used because they are the most recent. 

If the pumping cost is a0 per unit head, then the cost to be minimized is given by... 

Effect of catalyst pellet size on reactor volume and pumping cost requirements. 

Base the optimization on just the cost of the shell, tubes, and pumping costs for the gas. Ignore maintenance and repairs. 

The problem is to minimize the total cost, once produce specifications and the throughput are fixed and the product and feed pumping costs are fixed that is, Cp Cd, and Cb are fixed. After selection of the material of construction, the costs are determined that is, Cp, Cs, Cx are also fixed. 

The optimal plant operation can be determined by minimizing the total cost function, including steam costs, with respect to P (liquid pumping costs are negligible)... 

The process diagram in Figure 7—2 shows propylene and benzene being fed directly to the reactor. Chemical grade propylene with 6-10% propane is. used because the presence of the propane does not affect the reaction. A front-end depropanizer can be used if a refinery grade propylene stream is used. That reduces the extra pumping costs and dilution effects of the propane. 

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