Consumption rates

World resources of sulfur have been summarized (110,111). Sources, ie, elemental deposits, natural gas, petroleum, pyrites, and nonferrous sulfides are expected to last only to the end of the twenty-first century at the world consumption rate of 55.6 x 10 t/yr of the 1990s. However, vast additional resources of sulfur, in the form of gypsum, could provide much further extension but would require high energy consumption for processing. 

On a uniform calorific value basis, coal constitutes 69% of the total estimated recoverable resources of fossil fuel in the United States. Petroleum and natural gas are about 7% and oil in oil shale, which is not as of this writing used as a fuel, is about 23%. The 1989 total recoverable reserves of coal are about 500 times the 1989 aimual production (2), whereas the reserves of oil and gas are smaller, the production and consumption rate of oil and gas in the United States is three times that of coal. 

Some 637—1075 biUion metric tons is classified as anthracite and biturninous coals of which 10% is estimated to be suitable for cokemaking. Thus this 60—108 biUion metric tons of coking coal, if recovered in a fully usehil form, represents enough coal to supply coke plants at 1990 consumption rates for about 100—200 years. North America is estimated to possess about 130 biUion metric tons of biturninous coal of which, perhaps, one-tenth would be classified as coking coal, most of which resides in the United States (4). 

C = consumption rate (tonne year ) r - fractional growth rate (% year ) t = time. Chapter 3 Definition of Stress, Strain, Poisson s Ratio, Elastic Moduli... 

In the application of magnesium anodes for enamelled boilers, the consumption rate of the anodes is determined less by current supply than by self-corrosion. The calculation of life from data on protection current requirement, /, and anode mass, m, is difficult because the a value is so low. 

On the basis of available practical experience, the consumption rate of magnesium anodes in enamelled boilers is lower than 3 mm a". For a rod anode with a diameter of 33 mm, this corresponds to a life of over 5 years. As a guideline for the required anode mass, 200 to 250 g per m of internal surface is recommended [27]. 

Impressed current anodes of the previously described substrate materials always have a much higher consumption rate, even at moderately low anode current densities. If long life at high anode current densities is to be achieved, one must resort to anodes whose surfaces consist of anodically stable noble metals, mostly platinum, more seldom iridium or metal oxide films (see Table 7-3). 

Iridium on valve metals is suitable if the consumption rate of platinum is too high at elevated temperatures or critical composition of the medium. Mostly platinum-iridium alloys are used with about 30% Ir, because coating valve metals with pure iridium is somewhat complicated. For the same reason, other noble metals such as rhodium cannot be used [21]. At present there is little price difference between platinum and iridium. 

Good results are obtained with oxide-coated valve metals as anode materials. These electrically conducting ceramic coatings of p-conducting spinel-ferrite (e.g., cobalt, nickel and lithium ferrites) have very low consumption rates. Lithium ferrite has proved particularly effective because it possesses excellent adhesion on titanium and niobium [26]. In addition, doping the perovskite structure with monovalent lithium ions provides good electrical conductivity for anodic reactions. Anodes produced in this way are distributed under the trade name Lida [27]. The consumption rate in seawater is given as 10 g A ar and in fresh water is... 

A current with ripples can lead to a high consumption rate for platinized titanium anodes and their premature failure. The residual ripple should be limited to 5% (see Section 7.2.2) [7],... 

Gas velocihes can also be measured with anemometers (rotating vane, hot wire, etc.), from visual observations such as the velocity of smoke puffs, or from mass balance data (knowing the fuel consumption rate, air/ fuel ratio, and stack diameter). 

Step 5.2 Determine the Inputs to Unit Operations. Once you ve determined the net ilMEC N 4KLaiNiriAl Sf SSVfBN unit operation. If accurate information about raw-material consumption rates for egtii i(aiiigistdblt itfidisnmPl iiKinettsstOfcldferasri ... 

Toxicity alucs for carcinogenic effects also can be c.xprcsscd in terms of risk per unit concentration of the substance in the medium where human contact occurs. These measures, called unit risks, are calculated by dividing the slope factor by 70 kg and multiplying by the inhalation rate (20 m /day) or the water consumption rate (2 L/day), respecti ely, for risk associated with unit concentration in air or water. Where an absorption fraction less than 1.0 has been applied in deriving the slope factor, an additional conversion factor is necessary in the calculation of unit risk so that the unit risk will be on an administered dose basis. The standardized duration assumption for unit risks is understood to be continuous lifetime c.xposure. Hence, when there is no absorption conversion required ... 

During the late 1990s annual consumption rates of commercial energy ranged from less than 25 kgoe (or... 

U.S. Department of Transportation. (1973). The Effect ot Speed on Automobile Gasoline Consumption Rates. Washington, DC Federal Highway Administration. 

All fossil fuels are considered unsustainable because someday they will reach a point of depletion when it becomes uneconomic to produce. Petroleum is the least sustainable because it is the most finite fossil fuel. Although levels of production are expected to begin declining no later than 2030 (U.S. production peaked in 1970), the U.S. and world resei ves could be further expanded by technological advances that continue to improve discoveiy rates and individual well productivity. The extraction of oils found in shales (exceeds three trillion barrels of oil equivalent worldwide) and sands (resei ves of at least two trillion barrels worldwide) could also significantly increase reserves. The reserves of natural gas are comparable to that of oil, but natural gas is considered a more sustainable resource since consumption rates are lower and it burns cleaner than petroleum products (more environmentally sustainable). 

Figure takes into account fast reactors. It is stated in original document that predictions are particularly speculative. 1971 consumption rates were taken as oil 2500 Mtoe gas 900 Mtoe coal 1500 Mtoe. 

Materia Consumption rate or operating current density Notes... 

Graphite 2 -5-10 A/m Consumption rate very much less than steel or cast iron (< 1 kg/Ay) chloride ions reduce consumption... 

The anode capacity is the total coulombic charge (current x time) produced by unit mass of an anode as a result of electrochemical dissolution. It is normally expressed in ampere hours per kilogram (Ah/kg) although the inverse of anode capacity, i.e. the consumption rate (kg/Ay) is sometimes used. 

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