Irreversible processes power generation

Although it may be interesting to compare the entropy generated by various irreversible processes in a given system, in order to make real progress with the theory, we must postulate relations between the flows and forces that we have discussed in the last section. Assuming that the flows depend on the forces, we can expand the functional relationship between a flow, Jk, and the forces, Xt, in a multivariable power series ... 

A prime lesson in irreversible process theory is based on Figure 3.1, illustrating Joule s experiment. In that experiment, shaft power was dissipated irreversibly by a rotating paddle, to become energy in a tank of near ambient temperature water. The chaotically interactive translation, vibration and rotation of fluid molecules is energy.Energy is accessible to generate power, only by cyclic processes (heat cycles) as defined by Carnot. (Carnot cycle theory is outlined in Chapter 1.)... 

CH4 the efficiency of the fuel cell power generation process could, therefore, approach 100 percent. However, work is lost and a corresponding quantity of heat is produced by irreversibilities both in fuel cell operation —... 

The above relate to Figure A.2, which shows an enhanced version of Figure A.l, designed to allow operation of the cell at any selected high temperature and pressure. Isentropic circulators are incorporated to generate the increased conditions. The cell generates heat which is passed without temperature difference to a Carnot cycle to generate power, a reversible process free from the irreversibility of combustion. 

A further experiment was carried out to study the possible role of tars in the oxidation process which transforms the imine into the oxime by 0-insertion. Indeed, no decisive data are available to exclude any influence of the presence of tars on the catalyst surface on the reaction of oxidation of the imine to oxime. On the other hand, the many evidences seem to indicate a possible correlation between the oxidation power exhibited by the simple amorphous silica samples and the presence of organic residues irreversibly adsorbed. In particular, an important indication is the extrapolation of the rate of formation of the oxime at t=0 h. The value obtained is about zero suggesting that the pure silica can not catalyze the oxime formation. In order to confirm this hypothesis, other catalytic tests were carried out under standard conditions and the first hour of reaction was studied in more detail. The results, reported in figure 6, showed that the rate of formation of the oxime at very beginning of the test with the time-onstream is really null. This datum demonstrates that the simple silica can not generate the oxime and that the oxidizing power is related to the presence of the tars and that the activation process which takes place in the first 10 h of the reaction is due to the increase of the tars. 

---