**7. Conclusions**

In this research, the acetylene hydrogenation over Pd-Ag supported α-Al2O<sup>3</sup> was investigated in a differential reactor. The full factorial design method, based on the cubic pattern was used to determine the experiments, considering hydrogen to acetylene ratio, temperature, gas hourly space velocity, and pressure as dependent variables. The fresh and spent catalysts were characterized by SEM, TEM, DTG-TGA, XRD, and BET tests. It is concluded from SEM and BET tests, that coke build-up on the external surface of the catalyst increases surface area and decrease pore mean diameter. Then, a detailed reaction network was proposed based on the Langmuir-Hinshelwood-Hougen-Watson approach, considering ethane, 1-butene, and 1,3-butadine as side products. The coefficients of the proposed kinetic model were calculated, based on experimental data. In addition, the industrial Tail-End hydrogenation reactors were modelled, and a decay model was proposed to predict catalyst activity. The results showed that applying hydrogen rich stream increases 1-butene concentration in the reactor. Based on the simulation results the acetylene molar flow rate in the outlet stream from Guard bed increases during the process run-time and approaches from 0.19 to 0.21 mol s−<sup>1</sup> .

**Supplementary Materials:** The following are available online at http://www.mdpi.com/2227-9717/7/3/136/s1.

**Author Contributions:** O.D.: Conceived and designed the analysis, Collected the data, Contributed data or analysis tools, Performed the analysis, Wrote the paper; M.R.R.: Conceived and designed the analysis, Contributed data or analysis tools, Performed the analysis, Wrote the paper; A.S.: Conceived and designed the analysis, Performed the analysis, Wrote the paper.

**Conflicts of Interest:** The authors confirm that there are no known conflict of interest associated with this publication and there has been no significant financial support for this work that could have influenced its outcome.
