Work analysis

Table 2. Lost-Work Analysis for a Fired Heater...

Fired Heater as a Heat-Exchangee System. Improved efficiency in fired heaters has tended to focus on heat lost with the stack gases. When stack temperatures exceed 150°C, such attention is proper, but other losses can be much bigger when viewed from a lost-work perspective. For example, a reformer lost-work analysis by Monsanto gave the breakdown shown in Table 2. 

An alternative to the lost-work or entropy-generation analysis is a work analysis. This is based on Eq. (4-366), written... 

A work analysis gives each of the individual work terms on the right as a fraction of W. 

Work Analysis Since the process requires work, Eq. (4-375) is appropriate for a work analysis. The various terms of this equation appear as entries in the following table, and are on the basis of 1 mol of entering air. 

I.. Aiidersson, G. Rosen. Detailed work analysis for control of exposure to auborne eonrami-rianti m the workplace.. Appl. Occup. Environ. Hyg. 10(6), 1995. 

This is a technique developed by Petersen and Rasmussen. The full documentation of the technique is extensive and only an outline can be provided here. Full details are available in Petersen (1985). The major steps in performing work analysis are as follows ... 

The process line AB is shown here as a straight line for convenience of working. Analysis of the air as it passes through a cooling coil shows the line to be a slight curve. 

Garcia-Viloca M, Gao J, Karplus M, Truhlar DG (2004) How enzymes work Analysis by modem rate theory and computer simulations. Science (Washington, DC) 303(5655) 186-195... 

Garcia-Viloca, M. Gao, J. Karplus, M. Truhlar, D.G., How enzymes work analysis by modern reaction rate theory and computer simulations, Science 2004, 303, 186-195. 

PLANNING AND EXECUTION OF EXPERIMENTAL WORK ANALYSIS OF RESULTS... 

For most exploratory work, analysis of the organic phase is not necessary. If no volume change of the phases occurs and no third phase or crud is formed, the analysis of the aqueous raffinates is sufficient, since the metal concentration in the solvent can be readily calculated from the initial metal concentration of the feed solution and the phase ratio used. 

Arnold and Ibbotson, Steel Works Analysis (Pitman, London), 1919, 212, 265 Travers, Compt. rend., 1918,166,494 Kelly, Myers, and Illingworth, J. Ind. Eng. Ghent., 1917, 9. 852. 

In any case, the principles of exergy analysis or lost work analysis are important. 

Table III. Demethanizer Section Lost Work Analysis...

A work aiialysis here expresses each of the individual work terms on the right as a fraction of tV,. A work analysis cannot be carried out in the case where a process is so inefficient that vVideal is positive, indicating ihat the process should produce work, but Ws is negative, indicating that the process in fact requires work. A lost-work or entropy-generation analysis is always possible. 

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