PDF Publication Title:
Text from PDF Page: 012
Energies 2019, 12, 809 12 of 41 The authors also reported that phenate formation on the silica surface was very low in comparison to Al2O3 support. MgO has also been used as supporting material in hydroprocessing reactions; for example, Yang et al. [90] investigated CoMo catalysts supported on MgO for the hydroprocessing of phenol and reported high coke resistance which they attributed to the acidic nature and high dispersion of MoO3/MoS2 on the MgO surface. By comparing the three deoxygenation reactions one observes that hydrogen consumption is higher in the order HDO > deCO > deCO2 and, therefore, deCOx reactions are preferable despite the expense of carbon loss into CO and CO2. Also, HDO reaction over sulfided metal catalysts can contaminate the products with sulfur [91] and requires high H2 pressures that are mostly available only in centralized refineries. From the discussion above it is clear that there is great need for the development of deoxygenation catalysts that will be free of sulfur, and at the same time be highly active and selective and also resistant to deactivation in low H2 pressure. The deCOx reactions are catalyzed by simpler supported metal catalysts and also need lower H2 pressures. Due to these advantages research was undertaken for the selective deoxygenation of triglycerides over catalysts that promote the deCOx such as Pt, Pd [74,84,86,98] and especially Ni-based catalysts which show comparable activity to noble metals at a much lower cost [91,99–101]. Peng et al. examined the HDO of stearic acid over Ni catalysts supported on two types of zeolites, HZSM-5 and HBeta [102]. The authors reported that Ni/HBeta catalysts were more selective to C17 and C18 alkanes promoting the HDO reaction and eliminating cracking. In contrast, the narrower pores and higher concentration of Brönsted acid sites of the Ni/HZSM-5 catalysts led to a higher effective residence time, which in turn resulted at an increased degree of cracking. Thuan Minh et al. [103] investigated the catalytic HDO of phenol over Ni–Cu/HZSM-5 and Ni–Co/HZSM-5 bi-metallic catalysts and found that the conversion and selectivity was decreased with the addition of Cu, and attributed this behavior to a negative synergistic effect. In contrast, the addition of Co (10Ni–10Co) resulted in an increase of activity and selectivity, due to the formation of a NiCo2O4 spinel phase, which also improved resistance to coke deposition. Wu et al. [104] examined the effect of the support on non-sulfided catalysts that were based on Al2O3, ZrO2 and SiO2 for Ni2P catalyst on the HDO of guaiacol. The acidic strength decreased in the order of Al2O3 > ZrO2 > SiO2, which was also the case for the Ni2P catalysts (i.e., the different supports had analogous acidic strengths). SiO2, being the support with the lowest acidity, led to the strongest association with Ni and also allowed P to maintain its fully phosphided state; it also led to decreased coke deposition. Lercher et al. [105] used a number of different supports and active phases in order to investigate the HDO of palmitic acid and reported that activity decreased in the order of: 15%Ni/ZrO2 = 5%Ni/HZSM-5 (Si/Al = 200) > 5%Ni/HBEA[d] (SiAl = 180) > 10%Ni/ZrO2 > 5%Ni/ZrO2 > 5%Pd/ZrO2 > 5%Pt/ZrO2 > 3%Ni/ZrO2 > 5%Ni/Al2O3 > 5%Ni/SiO2 > 5%Pt/C > 5%Pd/C. The zeolites and ZrO2 with weak and medium acid sites on the surface exhibited much higher catalytic activity than the SiO2, Al2O3 and activated carbon, with the same nickel content. The authors also argued that ZrO2 participated in the HDO process, leading to the much higher activity. Kumar et al. [106] examined the deoxygenation of stearic acid over Ni/HZSM-5, Ni/Al2O3 and Ni/SiO2, with weak and medium acidity. The results showed that the Ni/HZSM-5 was more active (two times higher) than the Ni/Al2O3 and Ni/SiO2, however, the Ni/HZSM-5 exhibited high selectivity to octadecane while the other two catalysts were more selective to heptadecane. Similarly, Zuo et al. [107] prepared sulfur-free Ni catalysts supported on SiO2, γ-Al2O3, SAPO-11, HZSM-5, and HY and tested them in the HDO of methyl palmitate to produce renewable diesel. The acidic strength of the catalysts increases in the order of: 7wt% Ni/SiO2 < 7 wt% Ni/ SAPO-11 < 7wt% Ni/γ-Al2O3 < 7wt% Ni/HZSM-5 < 7wt% Ni/HY. Moreover, the Ni/SAPO-11 catalyst exhibited higher catalytic activity in comparison to the other samples, which the authors attributed to the presence of both weak and medium strength acid sites present in the SAPO-11 support. An extensive review on the development of Ni-based catalysts for the transformation of the natural triglycerides into green diesel has been published recently by Kordulis et al. [91]. A review of the catalytic research on the hydro-processing of the triglycerides is presented in Table 5 [72–119].PDF Image | Green Diesel: Biomass Feedstocks, Production Technologies
PDF Search Title:
Green Diesel: Biomass Feedstocks, Production TechnologiesOriginal File Name Searched:
energies-12-00809.pdfDIY PDF Search: Google It | Yahoo | Bing
NFT (Non Fungible Token): Buy our tech, design, development or system NFT and become part of our tech NFT network... More Info
IT XR Project Redstone NFT Available for Sale: NFT for high tech turbine design with one part 3D printed counter-rotating energy turbine. Be part of the future with this NFT. Can be bought and sold but only one design NFT exists. Royalties go to the developer (Infinity) to keep enhancing design and applications... More Info
Infinity Turbine IT XR Project Redstone Design: NFT for sale... NFT for high tech turbine design with one part 3D printed counter-rotating energy turbine. Includes all rights to this turbine design, including license for Fluid Handling Block I and II for the turbine assembly and housing. The NFT includes the blueprints (cad/cam), revenue streams, and all future development of the IT XR Project Redstone... More Info
Infinity Turbine ROT Radial Outflow Turbine 24 Design and Worldwide Rights: NFT for sale... NFT for the ROT 24 energy turbine. Be part of the future with this NFT. This design can be bought and sold but only one design NFT exists. You may manufacture the unit, or get the revenues from its sale from Infinity Turbine. Royalties go to the developer (Infinity) to keep enhancing design and applications... More Info
Infinity Supercritical CO2 10 Liter Extractor Design and Worldwide Rights: The Infinity Supercritical 10L CO2 extractor is for botanical oil extraction, which is rich in terpenes and can produce shelf ready full spectrum oil. With over 5 years of development, this industry leader mature extractor machine has been sold since 2015 and is part of many profitable businesses. The process can also be used for electrowinning, e-waste recycling, and lithium battery recycling, gold mining electronic wastes, precious metals. CO2 can also be used in a reverse fuel cell with nafion to make a gas-to-liquids fuel, such as methanol, ethanol and butanol or ethylene. Supercritical CO2 has also been used for treating nafion to make it more effective catalyst. This NFT is for the purchase of worldwide rights which includes the design. More Info
NFT (Non Fungible Token): Buy our tech, design, development or system NFT and become part of our tech NFT network... More Info
Infinity Turbine Products: Special for this month, any plans are $10,000 for complete Cad/Cam blueprints. License is for one build. Try before you buy a production license. May pay by Bitcoin or other Crypto. Products Page... More Info
| CONTACT TEL: 608-238-6001 Email: greg@infinityturbine.com | RSS | AMP |