# Glycerol Steam Reforming in a Pilot Plant: Effect of Temperature and Catalyst Load
## 4 Conclusions and Prospects  
The main findings of this work were the following:  
* A study about the steam reforming of glycerol in a pilot plant was carried out, obtaining considerable gas production (up to 35 L/min) at 850 \({}^{\circ}\)C with 100 g of catalysts (12% NiO). Under these circumstances, high hydrogen percentages were obtained, exceeding 40%. Thus, a semi-industrial production of hydrogen through GSR was proven.
* The most suitable catalyst for glycerol steam reforming in this experiment was 12% Ni, since, during the impregnation process, the support adsorbed the supplied solution properly, whereas in the rest of the cases, it was not possible, and the support tended to saturate.
* A considerable advantage is achieved when catalysts are used, compared to non-catalytic steam reforming, not reaching very high reaction temperatures.
* Due to the improvements introduced in the reactor, the pressure drop considerably decreased, and, therefore, the catalytic support was in contact with the gas for long enough.
* After several hours of continuous operation in the glycerol steam reforming plant, the results might be altered due to coke deposition and condensate that can be generated.
* For an optimal production in the plant, it should not be operating for more than 9 h, as this is the estimated useful life of the catalyst.
* The main disadvantage when it comes to catalyst implementation in this facility was coke deposition in the basket, which can promote catalyst deactivation.
* For a correct catalytic performance, some steps should be carried out for re-using it, such as oven cleaning, activation processes, placing it in the oven, etc.
* Finally, the main differences between optimal catalytic tests and non-catalytic ones make the use of a catalyst necessary as long as the process takes place for less than 9 h at a temperature of 850 \({}^{\circ}\)C.  
* Regarding the limitations of this work and prospects, it should be noted that further research about the sustainability of this process should be conducted, including advanced sustainability assessment tools such as a life-cycle assessment or exergy determination to prove the sustainability of the process at an industrial level.
* Also, further characterization of the catalyst (both fresh and spent) should be carried out, paying attention to parameters such as the specific surface area, element and phase composition, to determine key factors affecting its useful life.  
Conceptualization, J.F.G. and A.A.M.; methodology, A.A.M.; formal analysis, A.A.M. and A.G.A.; investigation, A.A.M., A.G.A. and S.N.-D.; resources, J.F.G.; data curation, A.A.M. and S.N.-D.; writing--original draft preparation, A.A.M., A.G.A. and S.N.-D.; writing--review and editing, S.N.-D.; visualization, J.F.G., A.A.M. and S.N.-D.; supervision, J.F.G.; project administration, J.F.G. and A.A.M.; funding acquisition, J.F.G. All authors have read and agreed to the published version of the manuscript.  
This research received no external funding.  
Not applicable.  
The authors would like to thank Green Fuel Extremadura for the glycerol provided.  
The authors declare no conflict of interest.