It is clear from the above section that the increase of the reaction side pressure has a significant role in the improvement of the performance of the CFFBMR. We have so far the best performance of the CFFBMR at a reaction side pressure of 30.0 bar. In this part of the investigation we are seeking further enhancement of the performance of the CFFBMR at a reaction side pressure of 30.0 bar by testing the influence of the number of hydrogen membrane tubes.
Fig. 12 shows the heptane conversion at various number of hydrogen membrane tubes (NH2 = 30, 40, 50) and a reaction side pressure of 30.0 bar. The effect of the number of hydrogen membrane tubes on heptane conversion is insignificant due to the fact that the reaction (1) is very rapid at these conditions and completed in a very small portion of the dimensionless reactor length. The corresponding hydrogen yield is shown in Fig. 13. The increase of the number of hydrogen membrane tubes from 30 to 50 gives further increase in heptane conversion of about 8.13%. The total increase in the exit hydrogen yield obtained by implementing a high reaction side pressure (30.0 bar) coupled with a high number of hydrogen membrane tubes (50 tubes) compared to that obtained at a reaction side pressure of 20.0 bar and a number of hydrogen membrane tubes of 30 as shown in Fig. 3c3 and Fig. 8 is about 41.43% and about 496.94% compared to the value obtained without hydrogen membrane as shown in Fig. 3c3. Further decrease in the H2/CO ratio to a good value of 1.15 is achieved by increasing the number of hydrogen membrane tubes to 50 as shown in Fig. 14. The increase of the number of hydrogen membrane tubes has a limited effect in decreasing the methane yield and a little effect in increasing the carbon dioxide yield as shown in Figure 15 and Figure 16, respectively.