Catalytic pathwayz and deactivation in alternative sources of fuel production: butene oligomerizaton and ship/shale-gasoils cracking

305 p.Catalytic pathways and deactivation on acid catalysts have been studied for two industrial catalytic processes implemented in the current refinery, oligomerization and FCC units, which are versatile for facing the recent changes in supply/demand of transportation fuels (gasoline and diesel) within the energy transition scenario. For this purpose, each process has been studied separately, in different types of reactors: fixed bed and operando UV-Vis cell reactors, for oligomerization and a riser simulator for FCC. Other feeds have been used: (i) 1-butene (n-butenes in equilibrium) for oligomerization; and non-conventional (shale oil) and conventional VGO, and MARPOL C type residue, for FCC. Likewise, two heterogeneous acid catalysts have been used: HZSM-5 and HY zeolite-based catalysts for oligomerization and FCC, respectively. The main goal has been to establish the effect of operating conditions (temperature, pressure, space time, partial pressure), the use of alternative feeds, especially to be incorporated into FCC units, on the catalytic performance (conversion, main lumped product selectivity-yield, and catalyst stability) and on coke de activation. Used catalysts have been analyzed using several characterization techniques: TPD-N2/TPO, HeTPD-GC/MS, soluble coke extraction, FTIR, and FT-ICR MS spectroscopies

Coke deactivation and regeneration of HZSM-5 zeolite catalysts in the oligomerization of 1-butene

The deactivation phenomenon of HZSM-5 catalysts (SiO2/Al2O3 ratio = 30–280) in the 1-butene oligomerization has been studied. Experiments were performed in a fixed-bed reactor at 175−325 °C; 1.5−40 bar; and, 2−6 g h molC−1. Used catalysts were analyzed by: temperature-programmed sweeping with N2 (TPS-N2), soluble coke analysis by gas chromatography/mass spectrometry (GC/MS); Fourier-transform infrared spectroscopy (FTIR); temperature-programmed oxidation (TPO), and; combined TPO/FTIR. The main deactivation cause is the oligomer (soft coke) confinement in the catalyst matrix, which depends on the reaction conditions (temperature and pressure). Soft coke is removed by TPS-N2 at 400 °C, whereas the remaining hard coke, by combustion. Two types of hard coke are distinguished, which are located in the catalyst matrix and in the zeolite micropores, being the second fraction more refractory to combustion. The low developed nature of soft coke facilitates catalyst regeneration, which is fully achieved by the combustion of hard coke at 500 °C.This work has been carried out with the financial support of the Ministry of Economy and Competitiveness of the Spanish Government (Projects PID2019/108448RB-100 and CTQ2016-79646-P), the ERDF funds and the Basque Government (Project IT1218-19). M. Díaz is grateful for the PhD grant from the Department of Education, University and Research of the Basque Government (PRE_2014_1_344). J. Valecillos and S. Izaddoust are thankful to the Ministry of Economy, Industry and Competitiveness of the Spanish Government for their grants BES-2014-069980 and BES-2017-080077, respectively. The authors also thank for technical and human support provided by IZO- SGIker of UPV/EHU and European funding (ERDF and ESF)

Coke deposition and product distribution in the co-cracking of waste polyolefin derived streams and vacuum gas oil under FCC unit conditions

The effect of co-cracking of high-density polyethylene (HDPE) or its pyrolysis wax together with vacuum gasoil (VGO) has been studied. The aim is to determine the content, nature, and location of coke while analyzing the impact on product distribution in the process. Four different feeds were used (VGO, VGO + 5 wt% HDPE, VGO + 20 wt% of wax, and 100 wt% wax) in experiments performed in a laboratory-scaled riser simulator, with similar conditions to those of the fluid catalytic cracking (FCC) unit: equilibrium catalyst; 530 degrees C; catalyst/feed mass ratio, 5; contact time, 6 s. The results of the different characterization techniques of the deactivated catalyst and the coke indicate that the catalyst fouling decreases notably by incorporating these waste streams, changing its nature to a more aliphatic (olefinic) one and its location towards the zeolite micropores. On the contrary, the coke formed from the VGO is more evolved and mainly constituted by polyaromatic components deposited on the mesopores of the catalyst matrix. Product distribution is also affected, increasing the yield of light cycle oil and keeping a relatively similar gasoline yield, with greater olefinity and lower aromaticity. Thus, the FCC shows great perspectives to valorize polyolefins, present in waste plastics, at great scale.This research was funded by the Ministry of Economy and Competitiveness (MINECO) of the Spanish Government (CTQ2015-67425R and CTQ2016-79646-P), the European Regional Development Fund (ERDF) and the Basque Government (IT748-13). Dr. Rodriguez is thankful to the University of the Basque Country UPV/EHU and Petronor S.A. (Zabalduz Programme). S. Izaddoust is thankful to the MINECO for her grant BES-2017-080077.This research was funded by the Ministry of Economy and Competitiveness (MINECO) of the Spanish Government (CTQ2015-67425R and CTQ2016-79646-P), the European Regional Development Fund (ERDF) and the Basque Government (IT748-13). Dr. Rodriguez is thankful to the University of the Basque Country UPV/EHU and Petronor S.A. (Zabalduz Programme). S. Izaddoust is thankful to the MINECO for her grant BES-2017-080077

Lessening coke formation and boosting gasoline yield by incorporating scrap tire pyrolysis oil in the cracking conditions of an FCC unit

We have studied the effect of adding scrap tire pyrolysis oil (STPO) as feed or co-feed in the cracking of vacuum gasoil (VGO) using a commercial equilibrated catalyst. The cracking experiments were performed in a laboratory scale fluid catalytic cracking (FCC) simulator using VGO, STPO, or a blend of the two (20 wt% of STPO), contact time = 6 s, catalyst/feed ratio = 5, and 530 °C. The composition of the different feeds has been correlated with the yield of products and the amount-location-nature of the deactivating species (coke). Our results indicate that adding STPO increases proportionally the gasoline yield, synergistically increase the yield of light cycle oil while uncooperatively decrease the yields of heavy cycle oil and coke. We further investigated the effect on coke formation, characterizing deeply the coked catalyst and coke. In fact, the coke deposited under the cracking of STPO is more aliphatic, lighter, and located in the micropores of the catalyst. The complete analysis of the coke fractions (soluble and insoluble) have lighted the peculiar chemistry of these species as a function of the type of feed used. The results point to a viable and economically attractive valorization route for discarded tires.Spanish Government CTQ2016-79646-P Ministry of Science, Innovation and Universities (MICINN) of the Spanish Governement RTI2018-096981-B-100 European Union (EU) European Commission Joint Research Centre 823745 Basque Government IT1218-1