Tanks estimating

Propylene is stored at 25°C in a tank at its saturation pressure. A 1-cm-diameter hole develops in the tank. Estimate the mass flow rate through the hole under these conditions for propylene ... 

The Tax Foundation, a nonprofit tax think tank, estimates that America spends 140 billion complying with the current tax code—a cost that would be reduced 94% by instituting a flat tax. 

In looking at the new size tank, estimates should be made of the shear rate profile around the system, and then using the relationship that viscosity is a function of shear rate, and the fact that it is shear stress... 

A 40-liter tank full of water at 15 °C is to be heated to 50 4 C by means of a 1-cm-OD copper steam coil having 10 turns of 30 cm diameter. The steam is at atmospheric pressure and its thermal resistance is negligibly small Neglecting the heat losses from the tank, estimate the heating time required. Hint Assume the coil as a horizontal cylinder.)... 

The effective saturation depth,, represents the depth of water under which the total pressure (hydrostatic plus atmospheric) would produce a saturation concentration equal to for water ia contact with air at 100% relative humidity. This can be calculated usiag the above equation, based on a spatial average value of T, measured by a clean water test. For design purposes,, can be estimated from clean water test results on similar systems, and it can range from 5 to 50% of tank Hquid depth. Effective depth values for coarse bubble diffused air, fine bubble diffused air, and low speed surface aerators are 26 to 34%, 21 to 44%, and 5 to 7%, of the Hquid depth, respectively. 

In many types of contactors, such as stirred tanks, rotary agitated columns, and pulsed columns, mechanical energy is appHed externally in order to reduce the drop si2e far below the values estimated from equations 36 and 37 and thereby increase the rate of mass transfer. The theory of local isotropic turbulence can be appHed to the breakup of a large drop into smaller ones (66), resulting in an expression of the form... 

Economic Aspects. U.S. manufacturers of fluorosulfuric acid are AUiedSignal and Du Pont. These companies have a combined aimual capacity estimated at 20,000 metric tons, most of which is used internally although some merchant sales exist. Fluorosulfuric acid is shipped in tank cars. 

Investment, Costs, and Prices for Barley and Malt. Estimated malthouse investment (1993) and costs for a new malthouse with annual capacity of 120,000 t are shown in Table 2. This malthouse is equipped with twelve 1,700-bushel steep tanks, eight 10,000-bushel germination compartments, and two double-deck kilns. The kilns are equipped with standard heat recovery units and indirect heat. 

The transport of phthalates by road tankers and ships within Europe is carried out by international companies with sophisticated tank cleaning facihties. Wash waters from these modem faciUties are passed through a series of separators to remove any residual plasticizer which is then incinerated. It is estimated that, as a result of cleaning and spillages, the maximum emission to the environment is 80 t/yr. 

By listening to the sound emitted from leaking tanks, it is possible to estimate not only the existence of, but also the location of, leaks in tank bottoms. Much work needs to be done in this area before it can be considered rehable. 

Figure 3 shows the prices of bromine in tank car quantities from 1976 to 1990. Although the price rose 99% over these years, an average of 5.0% a year, when inflation is taken into account, the price in constant dollars actually fell slightly over that period (51). Estimates of bromine production around the world are shown in Table 3. 

Economic Aspects and Shipment. Production worldwide of neopentanoic acid is estimated at 15 thousand metric tons per year. Both Shell (36) and Exxon (37) have aimounced expansions in capacity. Neopentanoic acid is shipped in heated tank cars, heated tank tmcks, and dmms. 

Overall Eactor Estimates. The next level of fixed capital estimate is based on a preliminary design that includes a flow sheet, material balances, energy balances, and enough equipment design to size all of the principal process equipment, including pumps and tanks. 

Category Eactor Estimates. Various capital categories can be related to total equipment costs by factors, reported as percentages of equipment cost. Both purchased equipment costs, including pumps, tanks (qv), and instmments and deHvered equipment costs, excluding instmments, but including some off-sites, have been used in this approach (1,2). 

A problem that affects the accuracy of the prediction of plating thickness is in estimating the actual current density. Current is not evenly distributed over the surface of the part being plated, rather, it takes the path of least resistance. Current also concentrates on sharper points, corners, and edges even the shape of the plating tank can have an influence on the current distribution. The difference in current and, subsequendy, the plate thickness distribution, is minimal when geometrically conforming anodes are part of the system, but this condition is not often achieved. 

Economic Aspects. The production of ethyl ether from 1956 through 1973 ranged from 29.5 to 48.6 x 10 kg as reported by Synthetic Organic Chemicals, U.S. Production and Sales. Production was estimated at 13.6-18 X 10 kg in 1986, 12.7 X 10 kg in 1989. Though 1990 U.S. production capacity was estimated at 25.5 x 10 kg, production was estimated as only 12 x 10 kg in 1991 (21). Much of the decrease has been the result of a decline in arsenal demand (smokeless gun powder). List prices for ether have been steadily increasing, and reached 1.12/kg by 1989, refined, tanks (fob). 

Base equipment includes all equipment within the battery limits whose cost is as significant as the cost of a pump. For example, storage tanks, knockout drums, accumulators, heat exchangers, and pumps are classed as main-plant items (MPl). Early in the development of the process-flow diagram, it is advisable to increase the estimated (MPl) cost by 10 to 20 percent to allow for later additions. When the scope of the process has been well defined, (MPl) costs should be increased by 1 to 10 percent. 

A. Pikiilik and H. E. Diaz [Chem. Eng., 84, 106-122 (Oct. 10, 1977)] presented a graphical method for estimating the fabricated cost of distillation cohimns and pressnre vessels, storage tanks, fired heaters, pnmps and drivers, compressors and drivers, and vacnnm eqnipment. 

Contrac tors bids offer the most rehable information on cost. Order-of-magnitude costs, however, may be required for preliminary studies. One way of estimating them is to obtain cost information from similar facihties and scale it to the proposed installation. Costs of steel storage tanks and vessels have been found to vaiy approximately as the 0.6 to 0.7 power of their weight [see Happel, Chemical Process Economics, Wiley, 1958, p. 267 also Williams, Chem. Eng., 54(12), 124 (1947)]. AU estimates cased on the costs of existing eqiiipment must be corrected for changes in the price index from the date when the equipment was built. Considerable uncertainty is involved in adjusting data more than a few years old. 

The cost of the filter station includes not only the installed cost of the filter itself but also that of all the accessories dedicated to the filtration operation. Examples are feed pumps and storage facihties, precoat tanks, vacuum systems (often a major cost factor for a vacuum filter station), and compressed-air systems. The dehvered cost of the accessories plus the cost of installation of filter and accessories generally is of the same order of magnitude as the dehvered filter cost and commonly is several times as large. Installation costs, of course, must be estimated with reference to local labor costs and site-specific considerations. 

If the tank has some headspace, as is usually the case, it is desirable to get a better estimate of the ac tual level, since tanks usually have some gas headspace even when filled with hquid. Two tank configurations are considered the gravity discharge tank (discharge is open to the atmosphere) and the pumped discharge tank. These calculations assume that the process is so rapid that an adiabatic model for the gas in the headspace is the correct choice. This is true when the drainage... 

The pumped-discharge case is generally more difficult to solve because of the uncertainty in deahng with negative numerical results. As a final answer, a negative value could indicate that the pump has completely emptied the tank however, as an intermediate value, it could mean that it is not a true solution. A simple check is to try a different initial estimate and see if the intermediate negative results disappear. 

Cone roof storage tanks could he correlated using /lb of steel vs. weight, but the roof support for larger tanks is difficult to estimate, as is the overall thickness. 

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