RESUMO
This work provided catalytic copyrolysis of spent lubricating oil (SLO) with waste low-density polyethylene (LDPE) using copper modification of a spent fluid catalytic cracking (sFCC) catalyst to produce diesel-like fuels in a microbatch reactor, which will lead to effective waste management, ensure sustainability, and serve as an alternative energy source. The effects of LDPE blended with SLO, temperature, reaction time, and catalyst loading using an inert nitrogen atmosphere were investigated on the yields and distributions of copyrolyzed oil, while metal modification of the sFCC was prepared and used to investigate the catalytic activity. The temperature and time of reaction played an important role in the gaseous contribution to the pyrolysis of SLO. The addition of the LDPE ratio in the catalytic copyrolysis, including Cu loading on a spent FCC template, also enhanced the acidity and was responsible for the catalytic activity, which could improve the product distribution and chemical compounds in a range of diesel-like fuels. It was shown that the pyrolyzed oil was in the range of C7-C26 with a maximum diesel-like fraction of 23.11 ± 2.88 wt % compared with the catalytic pyrolysis of SLO alone, which contained a diesel-like fraction of only 12.45 ± 1.92 wt %. It was noticed that the acid active site of the catalyst resulted in a carbon-carbon bond cleavage and further secondary reaction, leading to the conversion of the long residue fraction into a light oil product. In addition, the LDPE ratio in the catalytic copyrolysis could improve the product distribution and chemical compounds in a range of diesel-like compounds, as confirmed by the GC/MS analysis. Catalytic copyrolysis oil of the optimal process condition (0.7:0.3 mass molar of SLO/LDPE, 450 °C, 60 min, 3 wt % Cu-sFCC, and 10 wt % catalyst loading) mainly contains light hydrocarbons in the C7-C19 range. Accordingly, both the product selectivity and the conversion of the long residue to the diesel-like fraction were nearly stable (59.01 ± 1.36%) during the catalyst reusability test from one to three cycles without regeneration and significantly decreased after the fifth cycle. This is an indication that the copyrolysis enhanced the conversion of SLO by LPDE blended into smaller hydrocarbon compounds, and the catalytic activity therefore showed a major tendency toward the formation of diesel-like fractions (C8-C18).
RESUMO
This research aims to investigate steam biomass gasification in a pilot horizontal gasifier using rubber wood pellets (RWPs) and eucalyptus wood chips (EWCs) for producing syngas with an H2/CO ratio range of 1.8 to 2.3 for Fischer-Tropsch synthesis. The study was divided into two parts. One was carried out in a lab-scale reactor to determine the effect of temperature and CaO on the gas product composition and the efficiency of tar removal. Another part was determined by investigating the effect of the steam/biomass (S/B) ratio on the produced H2/CO ratios in the pilot horizontal gasifier, which used the optimum conditions of temperature and % loading of CaO for tar removal according to the optimal conditions from the lab-scale gasifier. The lab-scale gasifier results showed that H2 and CO2 increased with temperature due to primary and secondary water gas reactions and hydrocarbon reforming reactions. The water gas shift and hydrocarbon reforming reaction depressed the CO and CH4 contents with increasing temperature, respectively. The optimum gasifying temperature was 900 °C, which obtained H2/CO ratios of 1.8 for both RWPs and EWCs. The tar yield decreased with increasing temperature and was less than 0.2 wt % when using CaO as a tar-cracking catalyst. The operation of the pilot horizontal gasifier at the operating condition of 900 °C and a S/B ratio of 0.5 using 0.2 wt % loading of CaO for tar removal also produced a H2/CO ratio of 2.0. The supply of an external heat source stabilized the gasifying temperature, resulting in a stable syngas composition and production rate of 2.5 and 2.7 kg/h with H2/CO ratios of 1.8 and 1.9 for the RWPs and EWCs, respectively. In summary, the horizontal gasifier is another effective designed gasifier that showed high-performance operation.
RESUMO
Catalytic pyrolysis of polymer waste is an attractive alternative process for the conversion of large hydrocarbon compounds to useful products for the most reliable fueling and valuable chemicals, growing toward a circular economy and enhancing the reduction of waste materials. In this study, catalytic pyrolysis of waste polyethylene wax (WPEW) using a dual acid-acid catalyst and acid-base catalyst, which had various pore size distributions and included a strong active site, maximized the desirable yield and product distribution. The effect of the process conditions and synergy of activated carbon (AC) blended into both a spent fluid catalytic cracking catalyst (FCC) and magnesium oxide (MgO) catalyst was examined in a 3000 cm3 custom-built reactor at varying operating temperatures (400-470 °C), inert nitrogen gas flow rates (50 mL min-1), catalyst loading (1-5 wt %), and FCC-AC and MgO-AC ratios in the catalytic conversion of WPEW to obtain the highest amount of diesel-like oil. The results indicated that thermal cracking of WPEW at 420 °C by a fixed inert N2 flow rate of 50 mL min-1 obtained the highest liquid yield of 81.64 wt % and a diesel-like fraction of 35.51 wt %, while the catalytic conversion of WPEW under optimum conditions (temperature: 420 °C; fixed inert N2 flow rate: 50 mL min-1; catalyst load: 5 wt %; MgO-AC ratio: 0.5:0.5) achieved the highest liquid diesel-like yield of 41.92 wt %. Physicochemical analyses showed that the highest heating value of WPEW pyrolytic oil was 44.20 MJ kg-1, and the viscosity was 1.7 mm2 s-1 at 40 °C. The combination of MgO-AC as a dual catalyst illustrates a positive synergistic effect on the catalytic activity performance markedly, outstanding catalytic characteristics alongside high selectivity in pyrolysis of WPEW to paraffinic hydrocarbons in the diesel-like fraction.
