Refrigeration, costs

Refrigerant costs are important when considering the investment in filling and maintaining a full charge in a particular system. 

More accurate methods to calculate refrigeration costs will be discussed in Chapter 24. 

The demethanizer distillation column of an ethylene process works at extremely low temperatures. The feed is cooled with extremely small temperature differences of the order of 1°C to minimize the refrigeration costs associated with the cooling. What type of heat exchanger would you expect to be used for this duty ... 

Use of the new high temperature superconductors should reduce the refrigeration costs of the project. Unfortunately refrigeration is only a very small percentage of both the capital and running costs and so will probably not make the difference as to whether this becomes a viable mode of transport or not. 

Kureha and Lummus have similar processes. In these, simplification of the ethylene purification step allows significant reduction in investment cost, refrigeration cost, and compression cost. The cheaper ethylene can then be incorporated into ethylene-route processes for VCM to decided advantage, especially for smaller units. 

In one variation of the process, acetylene is completely hydrated with water in a single operation at 68 to 73°C using the mercuric-iron salt catalyst. The acetaldehyde is partially removed by vacuum distillation and the mother liquor recycled to the reactor. The aldehyde vapors are cooled to about 35°C, compressed to 37 psi (253 kPa), and condensed. It is claimed that this combination of vacuum and pressure operations substantially reduces heating and refrigeration costs. 

Refrigeration, cost of 811, 815 Regression analysis, 759-765 Renf cost of 205, 210 Repairs, cost of 203, 210, 269-270 Replacement evaluation, 329-336 Replacement value, definition of 277 Reports ... 

A catalytic de-waxing plant resembles other hydrotreating plants and operating condition need not be particularly severe. Operating costs can be significantly less than solvent de-waxing, especially for low-pour-point oils where refrigeration costs become prohibitive [7, 8]. 

Materials cost per ampere meter. In those applications where the critical current density and strain characteristics make the magnet technically feasible, we must consider the cost. We focus here on the superconducting materials cost and the total refrigeration cost including the cryostat and capitalized refrigerant costs. 

The other limiting case is that of a compact heavy magnet where the radiation heat leak is negligible. Then the cost ratio is independent of field and depends only on the ratio of the refrigeration costs and the superconducting... 

If the a.c. loss of YBaCuO is significant, the refrigeration costs scale more directly with capacity. The cost-crossovers are then much more sensitive to the absolute costs, and meaningful evaluation awaits more reliable data on real YBaCuO conductors, which would allow the development and analysis of realistic designs. 

The addition of water to hydrophobic ionic liquids can result in the formation of a triphasic system consisting of the ionic liquid + catalyst/water/organic product. The aqueous phase eventually contains the inorganic salt formed during the reaction. This approach has been applied in Pd-catalyzed cross-coupling reactions [84]. The products can also separate after the reaction by perturbation (of a latent biphasic system). This can be realized by tuning the temperature to crystallize the ionic liquid. But the refrigeration cost may be problematic, and some ILs may remain in the product. 

The experiment—specimen, transducer, holder—can be contained in a small volume. Thus, ancillary equipment can be scaled down correspondingly. For low-temperature studies, refrigeration costs are low. 

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