Economic distance

Pipeline transport of truck-delivered wood chips is only economical at large capacities and medium to long distances. For a one-way pipeline, the minimum economic capacity is >0.5 million dry t/yr. For a two-way pipeline, the minimum economic capacity is >1.25 million dry t/yr. At 2 million dry t/yr, the minimum economical distance for a one-way pipeline without carrier fluid return is 75 km, and for a two-way pipeline with carrier fluid return is 470 km. 

There are three important considerations in the selection of an injection zone. They are 1. Containment, 2. Injectivity, and 3. Interactions. A suitable injection zone should also be within a reasonable and economic distance from the compressor location. Large aquifers, depleted reservoirs, and zones that produce sour fluids can be suitable for use as an injection zone. 

The cost of haulage is an important factor, as it can equal the ex-works cost of aggregate at a distance of 50 km. For road transport by tipper wagon, the economic distance may be as low as 40 to 60 km. Rail transport may extend that distance to 200 km and water transport can extend the distance eonsiderably further. 

Country Portfolio Analysis (CPA) An analysis of country market attractiveness using statistics like income, population, and product consumption. It is recommended that this analysis be adjusted for cultural, administrative, geographic, and economic distance. (Distance still matters. Harvard Business Review, September 2001, pp. 129-147)... 

Catalyst particles are usually cylindrical in shape because it is convenient and economical to fonii tliem by extmsion—like spaghetti. Otlier shapes may be dictated by tlie need to minimize tlie resistance to transport of reactants and products in tlie pores tlius, tlie goal may be to have a high ratio of external (peripheral) surface area to particle volume and to minimize the average distance from tlie outside surface to tlie particle centre, witliout having particles tliat are so small tliat tlie pressure drop of reactants flowing tlirough tlie reactor will be excessive. 

Chlorine cannot be stored economically or moved long distances. International movements of bulk chlorine are more or less limited to movements between Canada and the United States. In 1987, chlorine moved in the form of derivatives was 3.3 million metric tons or approximately 10% of total consumption (3). Exports of ethylene dichloride, vinyl chloride monomer, poly(vinyl chloride), propylene oxide, and chlorinated solvents comprise the majority of world chlorine movement. Countries or areas with a chlorine surplus exported in the form of derivatives include Western Europe, Bra2il, USA, Saudi Arabia, and Canada. Countries with a chlorine deficit are Taiwan, Korea, Indonesia, Vene2uela, South Africa, Thailand and Japan (3). 

Launched ia 1959, N. A. Savannah operated very weU. Starting ia 1962, it made a goodwill voyage around the world. It was able to travel a distance of several times the earth s circumference on one fuel loading. However, the ship was not competitive economically with oil-powered merchant ships. The shielding was quite adequate, so that the reactor was safe. Nonetheless the vessel was opposed by antinuclear groups and the N.A. Savannah was eventually retired and put on display ia Charleston, South Carolina. In 1994, the ship was transferred to Norfolk, Virginia, to be held ia reserve. 

For some applications, either steam or electricity is simply not available and this makes the decision. It is rarely economic to install a steam boiler just for tracing. Steam tracing is generally considered only when a boiler already exists or is going to be installed for some other primary purpose. Additional electric capacity can be provided in most situations for reasonable costs. It is considerably more expensive to supply steam from a long distance than it is to provide electricity. Unless steam is available close to the pipes being traced, the automatic choice is usually electric tracing. 

The Majac jet pulverizer (Ho.sokawa Micron Powder Sy.stems Div.) is an opposed-jet type with a mechanical classifier (Fig. 20-55). Fineness is controlled primarily by the classifier speed and the amount of fan air dehvered to the classifier, but other effects can be achieved by variation of nozzle pressure, distance between the muzzles of the gun barrels, and position of the classifier disk. These pulverizers are available in 30 sizes, operated on quantities of compressed air ranging from approximately 0.6 to 13.0 mVmin (20 to 4500 ftV min). In most apphcations, the economics of the use of this type of jet pulverizer becomes attractive in the range of 98 percent through 200 mesh or finer. 

The hinctional element of tmn.sfer and transport refer.s to the rnean.s, facihtie.s, and appiirtenance.s ii.sed to effect the tran.sfer of wa.ste.s from relatively. small collection vehicles to larger vehicles and to transport them over extended distances to either processing centers or disposal sites. Transfer and transport operations become a necessity when haul distances to available disposal sites or processing centers increase to a point at which direct hauling is no longer economically feasible. 

The fuel value of most solid wastes is usually sufficient to enable self-supporting combustion, leaving only the incombustible residue and redlicing the volume of waste eventually consigned to sanitaiy landfills to only 10 to 15 percent of the original volume. The heat released by the combustion of waste can be recovered and utilized, although the cost of the recoveiy equipment or the distance to a suitable point of use for the heat may make its recoveiy economically infeasible. 

To transmit power over long distances is the basic requisite of economical transmission. Let us study equation (24.3). If we are able to maintain a unity p.f. between the transmitting and receiving ends, then for a lossless line... 

Buried steel pipelines for the transport of gases (at pressures >4 bars) and of crude oil, brine and chemical products must be cathodically protected against corrosion according to technical regulations [1-4], The cathodic protection process is also used to improve the operational safety and economics of gas distribution networks and in long-distance steel pipelines for water and heat distribution. Special measures are necessary in the region of insulated connections in pipelines that transport electrolytically conducting media. 

Cathodic protection with magnesium anodes can be just as economical as impressed current anode assemblies for pipelines only a few kilometers in length and with protection current densities below 10 xA m" e.g., in isolated stretches of new pipeline in old networks and steel distribution or service pipes. In this case, several anodes would be connected to the pipeline in a group at test points. The distance from the pipeline is about 1 to 3 m. The measurement of the off potential... 

The DPSE found an acceptably low risk that was dominated by releases during normal operation. The mean risk of the station was estimated to be 9E6 Sv/y to the individual at ihe sue boundary and 7E4 person-Sv/yr to the surrounding population to a distance of 100 km. The consequences of events beyond the design basis were not calculated but their frequency was predic(cd to be 4E-6 /rcactor-y which is acceptably low. The mean economic risk was estimated to be about 10 M /reactor-yr. 

Shorter center distance is a very practical design objective. Such a design uses space economically and allows for a stable operation. In general, center distances are limited by the physical dimensions of the sheaves, or the minimum angle of 6, i.e.. 150". Maximum drive centers are limited only by available V-belt stocked lengths. 

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