C34 Hydrocarbons boil at higher temperatures than desired for diesel or gasoline. Gasoline is approximately C5-C10,kero c11-c14 and diesel could be C11-C20.. There are also several choices for Hydrocracking catalyst. In general (but not always) amorphous catalyst will preferentially perform mid molecule cracking and zeolites will crack closer to the end of the molecule (often cleaving C4 or similar groups .that fit in a zeolite "cage") A commercial amorphous NiMo or NiW or even CoMo catalyst would be a good choice for this service. Researchers like to use Pt or Pd based catalyst but they are probably not necessary for the hydrocracking of a pure C34 Hydrocarbon with perhaps 1 or two rings but they will also work well.

You should probably also analyze your synthetic crude derived from algae to see if C34H58 realy is representative of the oil you are going to produce. Algae based oils I have seen often contain a lot of O in the structure this can be problematic because the O is readily hydrotreated to form H2O and breaks the molecule into pieces that may be too small for transportation fuels (C4 and lighter). There are some reserchers working on selective hydrotreating of Bio base oils that does not remove as much the O and still Isomerizes and/or cracks the hydrocarbon to form high value products but this is not yet a proven commercial process.

If you really have long chain paraffinic product without heteroatoms like S, N and O you should try to make high quality lubes and/or waxes out of it. High quality lubes tend to be highly branched paraffinic C30 to C40 Hydrocarbon compounds. High quality waxes tend to be long straight chain paraffins. C34H58 probably has 1 or 2 rings but it could still be a good material for lubes.

Hydroxyl forms to open the double bonds. Additional double bonds form in approach to equilibrium, but water vapor suppresses the formation of carbon dust and coke. Molecules carbon chains are broken at the hydroxyls where symmetries are weak.