## 3 Results
Data from some experimental studies in the literature are also shown in the same figure. It should be noted that while the \(T_{exh}\) values obtained from our study show the minimum exhaust temperatures required to self-sustain the process, the exhaust gas temperature values observed in experimental studies are independent of the dehydrogenation process. As shown in Figure 2, the exhaust gas temperature values observed with low amounts of hydrogen in the fuel may be sufficient to initiate dehydrogenation. It should be noted that the values for the different references indicated in the image are calculated using different fuel compositions. The obtained temperatures, especially in simulations 2, 3 and 4 (therefore, with the addition of CH\({}_{4}\)), have values consistent with those typically reached by the exhaust gases at the exit from the combustion chamber. Suppose the actual temperatures are lower than the tabulated ones (the minimum for the dehydrogenation process to occur). In that case, acting directly on the combustion process is possible. Otherwise, integrations with the engine system can be envisaged. Among these solutions, the most typical consist of exploiting electric energy to increase the temperatures (Joule effect) or using post-combustors [3]. The first solution would require an adequate electrical system, which is usually applied in vehicles that use fuel cells. The second one is more interesting since it strictly concerns the field of internal combustion engines. The latter system introduces hydrogen burners, which make it possible to supply the missing energy to implement the dehydrogenation process by directly burning a part of the hydrogen detached from the LOHC+ compound [3]. For each of the four cases, it is possible to compare the trends of the \(P_{des}\) values necessary for the dehydrogenation of the two compounds (H18-DBT and H12-NEC) as the RPM varies; the results are represented in the following Figures 3 and 4. The \(P_{des}\) required in selecting H12-DBT are decidedly lower than those necessary to dehydrogenase the H18-DBT compound, precisely because of the difference between their enthalpies. It can be remarked that, since the lines are straight, the most remarkable differences in terms  
Figure 2: \(T_{exh}\) trend as volumetric % of H\({}_{2}\) varies [10; 11; 12; 13]. of the \(P_{des}\) required are found for high RPM values. On the other hand, the differences are less marked for low RPM values. Table 8 summarizes the results obtained, indicating for each simulation and LOHC the respective obtained values of \(T_{exh}\) and \(P_{des,max}\), where the maximum dehydrogenation power is obtained at a regime of 6000 RPM. It should be noted that, since the power diagram represents a linear trend, if the value in one point is known (i.e., 6000 RPM), it is possible to identify the \(P_{des}\) for any other RPM by employing a simple proportion. H12-NEC needs a lower thermal power compared to H18-DBT, and then the exhaust temperatures required are lower for H12-NEC. However, this LOHC has a high melting point that can be overcome by designing specialized methods for storage and transportation that can maintain the necessary temperature or by combining H12-NEC with other chemicals to lower its melting point. Yet, these methods can add complexity and cost to the refueling process, which can make refueling less practical when used for vehicles. Figure 4: \(P_{des}\) values for Perhydro-N-Ethylcarbazole (H12-NEC). Figure 3: \(P_{des}\) values for Perhydro-dibenzyltoluene (H18-DBT).