Sai P. R. Katikaneni

Catalytic conversion of canola oil to fuels and chemicals: roles of catalyst acidity, basicity and shape selectivity on product distribution

Studies were performed at atmospheric pressure in a fixed-bed microreactor at temperatures of 400 and 500°C over HZSM-5, silicalite, silica, silica-alumina, γ-alumina, calcium oxide and magnesium oxide catalysts to determine the various roles of catalyst acidity, basicity and shape selectivity on canola oil conversion and product distribution. Results showed that the initial decomposition of canola oil to long chain hydrocarbons and oxygenated hydrocarbons was independent of catalyst characteristics. However, subsequent decomposition (secondary cracking) of the resulting heavy molecules into light molecules (gas or liquid) appeared to be greatly enhanced by the amorphous and non-shape selective characteristics of the catalyst (as in silica-alumina, γ-alumina and silica). In contrast, a high shape selectivity in a catalyst (as in HZSM-5 and silicalite catalysts) permitted a mild secondary cracking resulting in a low gas yield and a high organic liquid product yield. On the other hand, it was interesting to observe that the presence of basic sites in a catalyst (as in calcium oxide and magnesium oxide) strongly inhibited secondary cracking. This resulted in the production of high yields of residual oil and low gas yields. The production of C2ue5f8C4 olefins, n-C4 hydrocarbons and aromatic hydrocarbons of unconstrained sizes, which reflected thermal effects on the overall reaction scheme, were predominant in amorphous and non-shape selective catalysts. On the other hand, the formation of C2ue5f8C4 paraffins, branched chain and total C4 hydrocarbons as well as aromatic hydrocarbons of constrained sizes (C7ue5f8C9) which were predominant in the shape selective catalysts showed that, apart from the products formed due to thermal effects, the type, structure and sizes of other products are determined principally by the shape selective characteristic of the catalyst.

Catalytic conversion of a biofuel to hydrocarbons: effect of mixtures of HZSM-5 and silica-alumina catalysts on product distribution

Abstract The potential for producing hydrocarbons from the conversion of biofuels has been the focus of attention in recent years. In a preliminary study, we observed that it was possible to produce various types of liquid hydrocarbons and also to dramatically change the hydrocarbon content from aromatic to aliphatic by mixing silica-alumina and HZSM-5 catalysts in different proportions. In the present work, an in-depth study was undertaken in order to investigate the effect of various mixture compositions of silica-alumina and HZSM-5 on the yield and selectivity for liquid hydrocarbons. The biofuel used in the present study was produced by the rapid thermal processing of maple wood. The runs were performed in a fixed-bed microreactor operating at atmospheric pressure, 1.8–7.2 WHSV and 330–410°C. It was interesting to observe that for all catalyst mixtures, the optimum yields of organic liquid product (OLP) and total hydrocarbons were obtained at 370°C. The HZSM-5 content ( H f ) of the catalyst mixtures ranged between 0 and 40 wt.%. The catalysts were thoroughly characterized by the following techniques: X-ray powder diffraction, temperature-programmed desorption with ammonia, FT-IR and NMR spectroscopy and measurement of their BET and pore sizes. The yield of OLP increased with H f and ranged between 13 and 27 wt.% of the biofuel feed. Aliphatic hydrocarbons were the main products (37–77 wt.% of OLP), followed by aromatic hydrocarbons (2–38 wt.% of OLP). At low H f (below 10 wt.%), the main effect of HZSM-5 was to increase the extent of cracking and thereby increase the aliphatic hydrocarbon production. At H f > 10, a combination of cracking followed by shape selectivity resulted in the production of aromatic hydrocarbons at the expense of aliphatic hydrocarbons. The results were analyzed statistically in order to determine which factors (namely HZSM-5 content in the catalyst ( H f ), space velocity, temperature and their interactions) were mainly responsible for the formation of OLP and its hydrocarbon content. The results showed that all three factors affected the OLP yields rather significantly. However, the aliphatic hydrocarbon yield was mostly affected by the space velocity and H f , and the aromatic hydrocarbon yield was significantly affected by temperature and H f . A regression surface response model was used to relate the yields of these products with the above-mentioned factors.

The production of gasoline range hydrocarbons from Alcell® lignin using HZSM-5 catalyst

The conversion of a solvolysis lignin to useful chemicals and fuels was investigated using HZSM-5 catalyst. The study was carried out in a fixed bed reactor operating at atmospheric pressure, over a temperature range of 500°C–650°C, and weight hourly space velocities of 2.5 to 7.5 h−1. The major objective was to investigate the use of HZSM-5 catalyst in the production of both liquid and gaseous hydrocarbon products directly from the lignin. Conversion was high and ranged between 50% and 85% for the reaction conditions used. Using a WHSV of 5 h−1, the liquid product (LP) yield was 39 wt.% at 500°C but decreased to 34 wt.% at 600°C and then to 11 wt.% at 650°C. The highest yield of liquid product (43 wt.%) was obtained at 550°C with a WHSV of 5 h−1. In all the experiments, the liquid product mainly consisted of aromatic hydrocarbons (mostly benzene, toluene and xylene — with toluene dominating). The yield of toluene increased from 31 wt.% of the liquid product at 600°C (WHSV=2.5 h−1) to 44 wt.% at 650°C (WHSV=5 h−1). The total gas yield increased dramatically with increasing temperature but only moderately with increasing WHSV. The yields of the major components in the gas stream (propane, ethylene, propylene, carbon dioxide and carbon monoxide) were greatly affected by temperature.

Production of C4 hydrocarbons from Fischer–Tropsch synthesis in a follow bed reactor consisting of Co–Ni–ZrO2 and sulfated-ZrO2 catalyst beds

Abstract Fischer–Tropsch synthesis was performed in a fixed-bed microreactor over a single bed consisting of Co–Ni–ZrO 2 catalyst as well as over a follow bed configuration consisting of Co–Ni–ZrO 2 and sulfated-ZrO 2 catalyst beds for the selective production of C 4 hydrocarbons. A maximum C 4 hydrocarbon selectivity of 14.6 wt.% was obtained using the single bed approach at 250°C and weight hourly space velocities (WHSV) of 15 h −1 . When a follow bed approach was used, there was an impressive increase in the selectivity for C 4 hydrocarbons to a maximum of 24 wt.% and that for iso-C 4 hydrocarbons to a maximum of 13.8 wt.% from 14.6 and 5.5 wt.%, respectively. However, there was a rapid deactivation of the sulfated-ZrO 2 catalyst due to coking and sulfate reduction.

Catalytic Conversion of Canola Oil in a Fluidized Bed Reactor

Studies were conducted in a fluidized-bed reactor at atmospheric pressure, reaction temperatures in the range 400–500°C and fluidizing gas flow rates ranging from 175–275 mL/min to study the product distribution obtained from the conversion of canola oil over HZSM-5, silica-alumina and HS-Mix (a physical mixture containing 20 wt% HZSM-5 and 80 wt% silica-alumina).

Potential of producing high octane additives and hydrogen from biomass-derived oils

At present, natural gas, petroleum and coal are principal sources of fuels and a large variety of chemicals. These fossil-derived fuels usually contain sulfur and nitrogen compounds which are not desirable due to their release of pollutants such as SO/sub 2/, NO/sub x/ and carbon dioxide. Hence, there is a strong interest in developing alternative and renewable sources of liquid fuels which are environmentally friendly. Wood (or biomass) derived oils are attracting increasing interest in this respect. The major advantages of using biomass-derived oils are that they are almost sulfur and nitrogen free and also are carbon dioxide neutral. In this paper, the potential of producing high octane additives and hydrogen from biomass-derived oils is discussed by the authors.