Specifications reforming

Policy makers, practitioners, and scholars from a variety of disciplines have recently embraced a new approach to risk reduction in health care—a "systems approach"—without proposing any specific reforms of medical liability law. The Institute of Medicine (IOM) placed its imprimatur on this approach in its recent reports (Kohn et al., 2000 IOM, 2001). In its simplest form, a systems approach to risk reduction in health care posits that an injury to a patient is often the manifestation of a latent error in the system of providing care. In other words, a medical mishap is the proverbial "accident waiting to happen" because the injury-preventing tools currently deployed, including medical liability law, are aimed at finding the individuals at fault rather than the systemic causes of error. Coexistence of a systems approach to error reduction and medical liability law as a conceptual framework for policy makers implies that the latter is likely to evolve in an incremental fashion as the former makes more visible different aspects of the medical error problem. 

Because SOFCs operate at high temperature, they are capable of internally reforming fuel gases (i.e., CH4 and other light hydrocarbons) without the use of a specific reforming catalyst (i.e., anode itself is sufficient), and this attractive feature of high temperature operation of SOFCs has recently been experimentally verified. Another important aspect of SOFCs is that recycle of CO2 from the spent fuel stream to the inlet oxidant, as required by MCFCs, is not necessary because SOFCs utilize only O2 at the cathode. 

Figure 19. Battelle s methanol specific reforming catalyst. Reactor conditions atmospheric pressure, reactant feed 50 50 by weight methanol and water mixture, 24 000— 50 000 ii GHSV. The conversion was reported as moles methanol reacted/moles methanol fed. (Reprinted with permission from ref 91. Copyright 2002 Elsevier.)...

A communication strategy as described here is a relatively short, intense effort that precedes and accompanies a specific reform. It goes well beyond the normal outreach efforts that stable programs need to ensure that potential clients are aware of the programs. It is episodic, whereas outreach should be continuous. 

Depending on the specific reforming conditions, a reformate feed may contain 25-75% nonreactive components such as and water vapor. This results in a small but noticeable overpotential loss that can be precisely assigned to the concentration (dilution) and inertial (diffusion) effects. In addition, CO, a major component of the reformate mixture, has the same dilution effect as and H O, but has a greater impact on the rate of diffusion because (44) is higher than that of both Nj (Mf j =28) and H O (Afj O = 18) (Bird et al. 1960 Gu et al. 2004). Figure 6 compares the anode polarizations of Hj/CO mixtures with those of H /N mixtures under the same operating conditions. 

We developed the initial model using Reactor Inlet Temperature and associated temperature biases for each reactor. This is useful for a specific reformer plant however this method can mask the effect of reactor temperature on the process. 

For the refiner, the reduction in benzene concentration to 3% is not a major problem it is achieved by adjusting the initial point of the feed to the catalytic reformers and thereby limiting the amount of benzene precursors such as cyclohexane and Cg paraffins. Further than 3% benzene, the constraints become very severe and can even imply using specific processes alkylation of benzene to substituted aromatics, separation, etc. 

For example, in the case of light Arabian crude (Table 8.16), the sulfur content of the heavy gasoline, a potential feedstock for a catalytic reforming unit, is of 0.036 weight per cent while the maximum permissible sulfur content for maintaining catalyst service life is 1 ppm. It is therefore necessary to plan for a desulfurization pretreatment unit. Likewise, the sulfur content of the gas oil cut is 1.39% while the finished diesel motor fuel specification has been set for a maximum limit of 0.2% and 0.05% in 1996 (French specifications). 

We cite isomerization of Cs-Ce paraffinic cuts, aliphatic alkylation making isoparaffinic gasoline from C3-C5 olefins and isobutane, and etherification of C4-C5 olefins with the C1-C2 alcohols. This type of refinery can need more hydrogen than is available from naphtha reforming. Flexibility is greatly improved over the simple conventional refinery. Nonetheless some products are not eliminated, for example, the heavy fuel of marginal quality, and the conversion product qualities may not be adequate, even after severe treatment, to meet certain specifications such as the gasoline octane number, diesel cetane number, and allowable levels of certain components. 

Naphtha at one time was a more popular feed, and alkah-promoted catalysts were developed specifically for use with it. As of 1994 the price of naphtha in most Western countries is too high for a reformer feed, and natural gas represents the best economical feedstock. However, where natural gas is not available, propane, butane, or naphtha is preferentially selected over fuel oil or coal. 

Antimicrobial efficacy is also affected by demand in the cooling water system, specifically demand exerted by ammonia. Chlorine reacts with ammonia to form chloramines, which are not as efficacious as hypochlorous acid or the hypochlorite ion in microbiological control. Bromine reacts with ammonia to form bromamines. Unlike chloramines, bromamines are unstable and reform hypobromous acid. 

The carbon monoxide concentration of gas streams is a function of many parameters. In general, increased carbon monoxide concentration is found with an increase in the carbon-to-hydrogen ratio in the feed hydrocarbon a decrease in the steam-to-feed-carbon ratio increase in the synthesis gas exit temperature and avoidance of reequiUbration of the gas stream at a temperature lower than the synthesis temperature. Specific improvement in carbon monoxide production by steam reformers is made by recycling by-product carbon dioxide to the process feed inlet of the reformer (83,84). This increases the relative carbon-to-hydrogen ratio of the feed and raises the equiUbrium carbon monoxide concentration of the effluent. 

A modem petroleum refinery is a complex system of chemical and physical operations. The cmde oil is first separated by distillahon into fractions such as gasoline, kerosene, and fuel oil. Some of the distillate fractions are converted to more valuable products by cracking, polymerization, or reforming. The products are treated to remove undesirable components, such as sulfur, and then blended to meet the final product specifications. A detailed analysis of the entire petroleum production process, including emissions and controls, is obviously well beyond the scope of this text. 

Whenever corrosion resistance results from the formation of layers of insoluble corrosion products on the metallic surface, the effect of high velocity may be to prevent their normal formation, to remove them after they have been formed, and/or to preclude their reformation. All metals that are protected by a film are sensitive to what is referred to as its critical velocity i.e., the velocity at which those conditions occur is referred to as the critical velocity of that chemistry/temperature/veloc-ity environmental corrosion mechanism. When the critical velocity of that specific system is exceeded, that effect allows corrosion to proceed unhindered. This occurs frequently in small-diameter tubes or pipes through which corrosive liquids may be circulated at high velocities (e.g., condenser and evaporator tubes), in the vicinity of bends in pipelines, and on propellers, agitators, and centrifugal pumps. Similar effects are associated with cavitation and mechanical erosion. 

---