Availability loss

Protonation of the alkyne produces the more favourable secondary vinyl cation, which is then attacked by water, since water is the predominant nucleophile available. Loss of a proton from this produces an enol, which is transformed into a more stable isomeric form, the ketone. This transformation is termed tautomerism, and we shall meet it... 

Process information of various streams (streams 1 to 16) and their chemical thermal and pressure availabilities are given in Table III. Power inputs to the system (streams 17 to 20) and availability losses (streams 21 to 29) are given in Table IV. The streams marked as inputs from environment in figure 2 are considered to have zero availability. 

First lau analysis projects losses in sections 3 and 5 (drying and absorption) as 94.1 and 99.9 uhereas second lau analysis yields 2% and 23.5 respectively. Losses in uartn uater and stack gas are insignificant in the range of 1.4 and 0.5 based on second lau analysis compared to 52 and 1. 5 as projected by first lau analysis. Overall availability analysis of a sulphuric acid plant clearly brings out the fact that availability losses are only 4 and uhat are hitherto considered as heavy losses in acid coolers (52 as given by first lau analysis) are quite insignificant. 

Areas for improvement in effectiveness of availability exist uhere large consumptions and losses occur. Availability consumptions could be altered only by changing basic process route uhereas availability losses could be reduced by suitablo recovery processes. 

Even though availability losses are relatively insignificant compared to consumptions, recovery of this availability from acid coolers in the form of pouer generation and boiler feed uater preheating is quite economical. 

Minimum-Cost Network by the Thermodynamic (Minimum-Availability-Loss) Matching Rule. The thermodynamic matching rule states that "The hot process and utility streams, and cold process... 

TABLE 14.7 Energy and Availability Losses in a Coal-Fired Steam-Electric Generating Plant ... 

Component Energy losses (% of plant input) Availability losses (% of plant input)... 

When considering the above Ust, remember the time, equipment, or systems used for controlling the process in the normal manner may not be available. Loss of equipment and controls may mean the user cannot cool, purge, or drain the process before or after the emergency. 

The presence of liquid phases of some components of the mixture is then considered and a method to estimate the amounts of liquid phase of each component is discussed. The resulting liquid mixtures are treated as ideal solutions without consideration of any availability loss due to mixing. A formula for the availability of a moist air mixture is also discussed. 

The principal reason for this low efficiency is the availability loss caused by using high-quality fuel to perform a task that requires only low-grade energy. 

In some instances, at least, it is desirable to evaluate the efficiency of a plant and/or the unit operations. For, the importance of the absolute values of the consumptions is relative, to be compared with the input of availability to the plant (or unit), or to the product output from the plant. Also, the evaluation of availability losses with effluent outputs may be important to the assessment of inefficiencies. If it is desired to evaluate the inputs and outputs, entropy calculations alone do not suffice, unfortunately. Then, the availability must be calculated 6). For the case at hand, the effluent losses... 

Net rate of availability output from the process + Net rate of availability loss in effluents ... 

The rate of availability loss per unit height is the integrand... 

Costs for tower volume and power. The contribution of tower volume and availability loss to the cost of heavy water produced by the distillation of water in an ideal cascade may be evaluated when values are assigned to... 

This poor energy utilization compared with gaseous diffusion is inherent in the mass diffusion process. Using a thermodynamic argument similar to Sec. 4.8 for gaseous diffusion, Forsberg showed that the minimum ratio of availability loss rate to rate of production of separative work at any point in a mass diffusion screen is... 

A refrigeration heat exchanger provides an opportunity to study the tradeoff between the cost of availability loss and the capital cost of the exchanger. Explore the optimization opportunities of a refrigeration system. 

The determination of exposures that will respond to treatment existing or available loss control techniques or activities. 

NERC (North American Electric Reliability Council), 1991, Impact ofFGD Systems, Availability Losses Experienced by Flue Gas Desulfurization Systems, North American Electric Reliability Council, Princeton, NJ, July, pp. 1-35. 

---