The overhead stream S9 is then split into two streams S11 and S12 in splitter SP1. For this splitter an estimate of what is recycled back is given in table 3. Table 3 shows the estimates needed for the recycle streams S12, and S15, for splitters 1 and 2. Stream S12 is compressed in a compressor of efficiency of 75% to a pressure of 25.5 bar. The compressed gas S13 is then introduced into splitter SP-2, which splits the splitter into stream S14 and S15. Stream S14 is mixed with the fresh feed of hydrogen, and stream S15 is used to control the temperature of the reactor. The amount of the splits is given in Table 3. The stream S11 is part of the fuel gas.