Article pubs.acs.org/IECR
Deoxygenation of Triglycerides by Catalytic Cracking with Enhanced Hydrogen Transfer Activity Iori Shimada,*,† Shin Kato,† Naoki Hirazawa,‡ Yoshitaka Nakamura,‡ Haruhisa Ohta,§ Kengo Suzuki,§ and Toru Takatsuka⊥ †
Faculty of Textile Science and Technology, Shinshu University, 3-15-1 Tokida, Ueda, Nagano 386-8567, Japan Graduate School of Science and Technology, Shinshu University, 3-15-1 Tokida, Ueda, Nagano 386-8567, Japan § Research & Development Department, euglena Co., Ltd., 75-1 Ono, Tsurumi-ku, Yokohama, Kanagawa 230-0046, Japan ⊥ Technology Development Unit, Chiyoda Corporation, 4-6-2 minatomirai, Nishi-ku, Yokohama, Kanagawa 220-8765, Japan ‡
ABSTRACT: The efficient use of plant oils as alternative fuels was investigated by studying triglyceride deoxygenation in catalytic cracking using a fluid catalytic cracking catalyst with enhanced hydrogen transfer activity. Unsaturated triglyceride deoxygenation was rapid and complete, but small amounts of oxygenated products such as fatty acids, ketones, and aldehydes were produced from saturated triglycerides. Reaction product analysis showed that hydrogen transfer reactions between oxygenates and hydrocarbons produced by cracking fatty acid carbon chains caused hydrodeoxygenation even in the absence of hydrogen. Catalytic cracking of triglycerides with fatty acid carbon chains of various lengths showed that triglyceride deoxygenation is not affected by steric hindrance, and probably occurs on zeolite external surfaces, whereas secondary cracking of hydrocarbons occurs on the internal surfaces. We showed that catalytic cracking can be used for efficient conversion of triglycerides to hydrocarbons in the absence of hydrogen.
1. INTRODUCTION The efficient production of alternative fuels from biomass resources is a key technique for achieving a sustainable society. Plant oils are attracting increasing attention as alternatives to fossil fuels because they can be extracted from various resources such as inedible crops, waste cooking oils, and microalgae oils. Plant oils consist mainly of triglycerides and can be upgraded to alternative automotive fuels by chemical conversion processes such as transesterification, hydrodeoxygenation, and catalytic cracking. The most widely investigated and widespread process is transesterification with methanol to yield fatty acid methyl esters (FAMEs), which can be blended with petroleum-based diesel fuels.1−5 However, the energy densities of FAMEs are lower than those of diesel fuels because of their higher oxygen contents. The high oxygen content also results in poor thermal and oxidation stabilities, and this limits the maximum FAME content that can be blended with diesel fuels. Deoxygenation of triglycerides and their conversion to hydrocarbons are important for improving their energy densities and stabilities. Catalytic hydroprocessing is usually used,6−9 in which hydrodeoxygenation of triglycerides produces oxygen-free hydrocarbons. The produced hydrocarbons are sulfur free and can be blended with petroleum-based fuels at any level. The main disadvantage of this process is the use of a pressurized hydrogen atmosphere, which incurs high operating costs. In addition, the main reaction products under a pressurized © 2016 American Chemical Society
hydrogen atmosphere are saturated hydrocarbons, and they require further reforming for conversion to valuable unsaturated hydrocarbons that can be used as octane enhancers for gasoline and feedstock for bulk chemicals. A new process for converting triglycerides directly to unsaturated hydrocarbons in the absence of hydrogen is therefore needed. We investigated the conversion of triglycerides to hydrocarbons without a hydrogen atmosphere using a fluid catalytic cracking (FCC) process involving hydrogen transfer reactions. There are many reports in the literature of catalytic cracking of triglycerides and they have been summarized in review papers.10−14 The catalysts used include oxides, base, zeolites, mesoporous materials and their composites, as well as commercial FCC catalysts. Deoxygenation of triglycerides to give CO2, CO, and H2O occurs even in the absence of hydrogen. Among the deoxygenation reaction paths in the catalytic cracking of triglycerides, decarboxylation, yielding CO2, and decarbonylation, yielding CO, result in partial loss of the carbon resources contained in the triglyceride feedstock; however, hydrodeoxygenation, yielding H2O, can convert most of the carbon resources in the feedstock to hydrocarbons. The Received: Revised: Accepted: Published: 75
September 10, 2016 December 5, 2016 December 9, 2016 December 9, 2016 DOI: 10.1021/acs.iecr.6b03514 Ind. Eng. Chem. Res. 2017, 56, 75−86
Article
Industrial & Engineering Chemistry Research
In addition to a rare-earth-exchanged USY zeolite, the RFCC catalyst contains matrix components such as kaolin clay particles and alumina binders,17 and the effects of these on triglyceride deoxygenation also need to be investigated. It is difficult for triglyceride molecules to diffuse directly into zeolite micropores because of size restrictions. Bhatia and co-workers have widely investigated catalytic cracking of triglycerides on microporous−mesoporous composite catalysts, and achieved higher conversions and improved compositions of produced hydrocarbons compared with those obtained from reactions on simple zeolites.18−22 The enhancement of triglyceride cracking on microporous−mesoporous hierarchical catalysts has also been reported by other researchers.23,24 The matrix components of an RFCC catalyst, which contains macroscale and mesoscale pores, probably also contribute to the initial cracking of triglycerides. An understanding of the role of each component in an RFCC catalyst in triglyceride cracking will enable the design of catalysts that give efficient conversions. Considering the above, the aim of this research was to clarify the deoxygenation reaction mechanism in catalytic cracking of triglycerides on an RFCC catalyst with enhanced hydrogen transfer activity. We focused on the role of the zeolite and matrix parts of the RFCC catalyst. We analyzed the deoxygenation products in detail and compared the deoxygenation rates and selectivities in the cracking of triglycerides containing saturated and unsaturated fatty acids, which have different hydrogen-donating abilities. We also investigated the effects of steric hindrance on the deoxygenation of triglycerides by comparing the deoxygenation rates of saturated triglycerides with different carbon chain lengths. The effects of steric hindrance indicate the size of the deoxygenation reaction field and clarify the role of the zeolite and matrix parts of the RFCC catalyst. These results will provide strategies for the design of catalysts for efficient triglyceride conversion.
selectivity for deoxygenation reaction paths therefore significantly affects the conversion efficiency of triglycerides to hydrocarbons, but the factors determining deoxygenation selectivities have not been widely investigated. Hydrodeoxygenation, which is the most efficient deoxygenation path for triglyceride conversion, in catalytic cracking is considered to be limited because catalytic cracking is performed without a hydrogen atmosphere. We focused on the hydrogen atoms contained in the triglyceride feedstock itself. The amount of hydrogen atoms contained in a triglyceride molecule is enough for hydrodeoxygenation of the triglyceride ester bonds if they are used efficiently. We focused on hydrogen transfer reactions during catalytic cracking over zeolite catalysts to control the distribution of hydrogen atoms among the triglyceride derivatives. Hydrogen transfer reactions are bimolecular reactions between a hydrogen donor and a hydrogen acceptor, in which active hydrogen species are released from the hydrogen donor and received by the hydrogen acceptor. The most common example of a hydrogen transfer reaction in an FCC process is the reaction between naphthenes (hydrogen donors) and olefins (hydrogen acceptors), producing aromatics and paraffins. Because the conversion of olefins to paraffins results in production of gasoline with a lower octane value, FCC catalysts that suppress hydrogen transfer reactions have been designed recently. From a different perspective, however, hydrogen transfer reactions have an important role in determining the properties of produced hydrocarbons because they determine the distribution of hydrogen atoms among the produced hydrocarbons in reactions in hydrogen-free atmospheres. Enhancement of the hydrogen transfer activity during catalytic cracking of triglycerides is therefore expected to accelerate hydrodeoxygenation of triglycerides using only the hydrogens contained in the feedstock. Č erný et al. compared the catalytic cracking of six model feedstocks consisting of saturated and unsaturated triglycerides, fatty acids, and fatty alcohols over USY zeolites.15 The yields of CO2 and CO from the unsaturated triglycerides and unsaturated fatty acids were lower than those from the corresponding saturated feedstocks. They attributed the different CO2 and CO yields to reduction of carboxyl groups by hydrogen transfer reactions because the hydrogen-donating abilities of unsaturated feedstocks are higher than those of saturated feedstocks. In contrast, CO2 and CO were not formed in the reactions of fatty alcohols because dehydration was the dominant reaction. These results indicate that the selectivity for deoxygenation products is affected by the hydrogen transfer activity in the reaction fields and the structures of the oxygenated groups. It is therefore important to clarify the triglyceride deoxygenation mechanism and the effects of hydrogen transfer reactions on the deoxygenation rates and reaction paths over an FCC catalyst to design efficient catalysts for triglyceride conversion. Although acceleration of hydrogen transfer reactions is the opposite strategy to that used recently in FCC catalyst design, we have shown the effectiveness of the acceleration of hydrogen transfer reactions in the catalytic cracking of polycyclic aromatic hydrocarbons using a residual FCC (RFCC) catalyst.16 The RFCC catalyst contained a rare-earth-exchanged USY zeolite; it has high hydrothermal stability in the regeneration cycle of an FCC process and therefore maintains high hydrogen transfer activity even in an equilibrium state. In this study, we used the RFCC catalyst for triglyceride cracking and investigated the effect of hydrogen transfer reactions on triglyceride deoxygenation.
2. EXPERIMENTAL SECTION 2.1. Catalysts. Equilibrium RFCC catalysts (E-cat) with high (E-cat A) and low (E-cat B) rare-earth loadings were obtained from commercial RFCC units. In addition, a fresh RFCC catalyst was hydrothermally deactivated in a fluidized bed reactor under a 100% steam atmosphere at 800 °C for 12 h (Steamed-cat C). The rare-earth loading of Steamed-cat C was the same as that of E-cat A. Most of the catalytic cracking experiments performed in this study were conducted using Ecat A. In the experiments aiming at clarifying the effect of catalytic activity on the reaction products, the other catalysts (E-cat B and Steamed-cat C) were used and compared with Ecat A. In the petroleum industry, the activity of an FCC catalyst is evaluated based on the unit cell size (UCS). The UCS provides a measure of the total number of tetrahedral aluminum sites per unit cell, and the tetrahedral aluminum sites in zeolites are the main active sites in FCC catalysts. The UCS therefore correlates with the activity (product distribution, coke formation, isomerization, and hydrogen transfer) of the FCC catalyst.25−29 The three catalysts used in this study were characterized by X-ray diffraction (XRD; RINT 2550, Rigaku Co., Tokyo, Japan) using Cu Kα radiation. The UCS value of each catalyst was calculated from the diffraction peaks of the (533) and (642) planes; the results are shown in Table 1. 2.2. Feedstocks. The plant oil feedstocks were coconut oil (Kaneda Shoji Co., Ltd., Tokyo, Japan) and sunflower oil (Wako Pure Chemical Industries, Ltd., Osaka, Japan). Coconut 76
DOI: 10.1021/acs.iecr.6b03514 Ind. Eng. Chem. Res. 2017, 56, 75−86
Article
Industrial & Engineering Chemistry Research
oil) was varied between 1.5 and 6.0. N2 gas was added during feed injection at 19 mL min−1. After each test, the catalyst was stripped by purging with N2 gas at 5 mL min−1 for 15 min. During the reaction and stripping step, the liquid products were collected in a cold trap with two receiving vessels connected in series and maintained at 0 °C and −15 °C, respectively. Simultaneously, the gaseous products were collected in a gas buret by water displacement. In all the runs, the overall mass balances were between 92% and 103%. In this study, the residence time was expressed as the inverse of the weight hourly space velocity (WHSV) or that of the gas hourly space velocity (GHSV). The WHSV is a typical index of space velocity in the field of catalytic cracking and was calculated as the feed injection rate (g h−1) divided by the catalyst weight (g). The GHSV was calculated using the following equation, and is based on the number of molecules passing through the reactor under the assumption of an ideal gas.
Table 1. Unit Cell Sizes of FCC Catalysts Used in This Study Catalyst
E-cat A
E-cat B
Steamed-cat C
Unit cell size (Å)
24.27
24.27
24.56
oil consists mainly of saturated fatty acids, and sunflower oil contains unsaturated fatty acids. We also used model triglyceride compounds containing saturated fatty acids such as tricaprylin (Sigma-Aldrich Co., St. Louis, MO, USA), and trilaurin and tripalmitin (Tokyo Chemical Industry Co., Ltd., Tokyo, Japan). In addition, we investigated the reactions of a fatty acid, a ketone and an aldehyde, which were identified as reaction intermediates, to clarify the reaction pathways in triglyceride cracking. We used lauric acid (Wako Pure Chemical Industries, Ltd.), 12-tricosanone, and dodecanal (both Tokyo Chemical Industry Co., Ltd.) as a model of fatty acid, ketone, and aldehyde, respectively. The fatty acid compositions of the coconut oil and sunflower oil were determined using the method reported by Ichihara et al.30 Reagent-grade hexane, acetone, KOH, sulfuric acid (Wako Pure Chemical Industries, Ltd.), and methanol and acetic acid (Kanto Chemical Co., Inc., Tokyo, Japan) were used as received. A few drops of each plant oil were mixed with hexane (2 mL) and 2 M KOH/methanol solution (0.2 mL). The mixture was vortexed at room temperature for 2 min. The hexane layer was analyzed using thin-layer chromatography on silica gel plates (Merck KGaA, Darmstadt, Germany) to confirm that all the triglyceride molecules were converted to FAMEs; the solvent system was hexane/acetone/acetic acid (95:5:0.5 by volume). The developed lipids were visualized by spraying with 50 wt % sulfuric acid and heating at 135 °C. The FAMEs in the hexane layer were identified using a gas chromatography (GC) system (GC-390B, GL Sciences Inc., Tokyo, Japan) equipped with a flame ionization detector (FID). The column used for FAME fractionation was 3 m length and packed with Uniport C 80/100 coated with Unisole 3000 (GL Sciences Inc.). The obtained fatty acid compositions of the plant oils are shown in Table 2. 2.3. Catalytic Activity Test. Catalytic activity tests were conducted in a fixed-bed microactivity test reactor; it has been described in a previous publication.31 In each trial, the catalyst (2−6 g) was placed in the reactor and maintained at reaction temperatures between 450 and 500 °C. The plant oils or model compounds were fed into the reactor by a microfeeder while being heated electrically in a preheating line. The feed injection time was 75 s and the weight ratio of the catalyst to the oil (cat/
GHSV =
wfeed M feed
×
RT P
Vcat
Here, wfeed is the feed injection rate (g s−1), Mfeed is the molar weight of the feedstock (g mol−1), R is the gas constant (J mol−1 K−1), T is the reaction temperature (K), P is the atmospheric pressure (Pa), and Vcat is the catalyst volume (m3). For the coconut oil and sunflower oil, Mfeed was calculated based on the average of the fatty acid compositions shown in Table 1. The inverse of the GHSV was used as an index of the residence time to enable comparison of reaction rates for different feedstocks on the basis of the number of molecules rather than the weight. The amounts of H2, N2, CO, and CO2 in the gaseous products were determined using a GC system (GC-8A, Shimadzu Corp., Kyoto, Japan) equipped with a packed column (SHINCARBON-ST 50/80, Shinwa Chemical Industries, Ltd., Kyoto, Japan) and a thermal conductivity detector, with Ar as the carrier gas. The gaseous hydrocarbons, liquid hydrocarbons, and oxygenates in the liquid products were investigated using a GC system (GC-2014, Shimadzu Corp.) with a capillary column of length 60 m (BP1, SGE Analytical Science Pty. Ltd., Victoria, Australia) and a FID, with He as the carrier gas. The liquid hydrocarbons and oxygenates were also analyzed using a GC−mass spectrometry system (GCMSQP2010 Plus, Shimadzu Corp.) equipped with a capillary column of length 60 m (Rxi-1ms, Restek Corp., Bellefonte, PA,
Table 2. Fatty Acid Compositions of Coconut Oil and Sunflower Oil Used in This Study Coconut oil
a
a
Sunflower oil
Fatty acid
Number of carbon atoms
Number of double bonds
(wt %)
(mol %)
(wt %)a
(mol %)
Caproic acid Caprylic acid Capric acid Lauric acid Myristic acid Palmitic acid Stearic acid Oleic acid Linoleic acid Linolenic acid
6 8 10 12 14 16 18 18 18 18
0 0 0 0 0 0 0 1 2 3
0.8 9.4 6.4 45.9 17.3 9.0 2.5 6.8 1.9 −
1.3 13.0 7.6 46.9 15.7 7.3 1.9 5.0 1.4 −
− − − − − 7.3 3.7 32.6 56.4 Trace
− − − − − 7.9 3.6 32.3 56.2 Trace
Weight distribution of FAMEs after transesterification. 77
DOI: 10.1021/acs.iecr.6b03514 Ind. Eng. Chem. Res. 2017, 56, 75−86
Article
Industrial & Engineering Chemistry Research
yields in C and D in Figure 1 can be explained by water formation. However, in the cases of A and B in Figure 1, the calculated water yields under the same assumption are 12% and 11%, respectively, which cannot explain all of the “unknown” yields. This may be the result of the formation of largemolecule products that were not detected by GC-FID because of their high boiling points. Alternatively, the relative response factors of the oxygenates in the GC-FID assay may have been overestimated. Nevertheless, most of the reaction products were quantified in all the experiments and we can identify the trends in triglyceride deoxygenation based on these results. Catalytic cracking of coconut oil at a higher temperature resulted in higher yields of hydrocarbons; this reflects involvement of the deoxygenation reaction. Higher reaction temperatures also resulted in lower coke yields, unlike the case for common FCC reactions. This is probably because of the formation of heavy products with high boiling points, which cannot volatilize at the reaction temperatures. At higher reaction temperatures, the heavier products can volatilize and are stripped from the catalyst; for example, the reaction products of boiling point 480 °C are deposited on the catalyst and regarded as coke products in the reaction at 470 °C, whereas they are stripped from the catalyst and are included in the heavy liquid hydrocarbon or oxygenate yields in the reaction at 500 °C, resulting in a lower coke yield. The “coke” yield in Figure 1 therefore contains not only highly aromatized coke products but also heavy compounds with boiling points around the reaction temperatures. For sunflower oil, oxygenate formation was lower and the hydrocarbon yield was higher than those for coconut oil at the same temperature (Figure 1B,D). The sunflower oil was converted to smaller hydrocarbons than the coconut oil was, although the sunflower oil contained larger fatty acids than the coconut oil did, as shown in Table 1. These results suggest that triglycerides containing unsaturated fatty acids are deoxygenated and decomposed more rapidly than those containing only saturated fatty acids. The rapid cracking of unsaturated fatty acids can be explained by a mechanism involving a carbenium ion intermediate; this is the standard theory for catalytic cracking of hydrocarbons.33,34 In this mechanism, unsaturated hydrocarbons easily interact with protons on the Brønsted acid sites of the catalyst surface and form carbenium ions, resulting in consecutive β-scission and hydride transfer reactions. The protonation of saturated hydrocarbons requires an acid with a high proton-donor strength because it proceeds via unstable carbonium ions. The cracking of saturated hydrocarbons is
USA), with He as the carrier gas. Biphenyl (99.5%, SigmaAldrich Co.) was used as an internal standard in the GC-FID assay. Quantification of the hydrocarbons and oxygenates was based on the effective carbon number theory.32 The amount of coke deposited on the catalyst was determined from the difference between the weight of the reactor before and after the catalytic test. Hydrocarbon products were classified based on their carbon numbers or boiling points into the following groups: gaseous hydrocarbons (C1−C4), gasoline (C5 to 216 °C), heavy liquid hydrocarbons (>216 °C), and coke.
3. RESULTS AND DISCUSSION 3.1. Catalytic Cracking of Coconut Oil and Sunflower Oil. The catalytic cracking of coconut oil and sunflower oil using E-cat A was investigated at 450−500 °C. Figure 1 shows
Figure 1. Reaction product yields from catalytic cracking of coconut oil and sunflower oil at various temperatures (E-cat A, WHSV = 16 h−1); A, coconut oil at 450 °C; B, coconut oil at 470 °C; C, coconut oil at 500 °C; D, sunflower oil at 470 °C.
the reaction product yields from the catalytic cracking of each plant oil. Hydrocarbons were the main reaction products in all the experiments. As the oxygen-containing products, CO2 and CO were detected. Some oxygenates, e.g., fatty acids, ketones, and aldehydes, were detected only in the reaction products from coconut oil. Water droplets were visible in the liquid products from both plant oils but this was not quantified. Assuming that all the oxygen atoms contained in the feedstock were converted only into the detected oxygenates, CO2, CO, and water, the water yields in C and D in Figure 1 can be calculated from the oxygen balance to be 13% and 8%, respectively. These values are almost consistent with the “unknown” yields in Figure 1, indicating that the “unknown”
Figure 2. Carbon number distributions of hydrocarbons produced from catalytic cracking of coconut oil (a) and sunflower oil (b) (470 °C, E-cat A, WHSV = 16 h−1). 78
DOI: 10.1021/acs.iecr.6b03514 Ind. Eng. Chem. Res. 2017, 56, 75−86
Article
Industrial & Engineering Chemistry Research
Figure 3. Reaction product yields from the catalytic cracking of trilaurin at 470 °C on E-cat A: (a) hydrocarbons, CO2, CO, and coke, and (b) oxygenates.
coke at different residence times are shown in Figure 3a. The produced oxygenates were mainly lauric acid (C12 fatty acid), dodecanal (C12 aldehyde), 12-tricosanone (C23 ketone), and 2tridecanone (C13 ketone), and their yields at different residence times are shown in Figure 3b. In addition to these oxygenates, acrolein, methyl laurate, vinyl laurate, and 3-tetradecanone (C14 ketone) were formed, but their yields were so small that they are not shown in Figure 3. The yields of hydrocarbons, CO2, CO, and coke increased with increasing residence time; this reflects involvement of the deoxygenation reaction. All the oxygenates produced were shown to be reaction intermediates because their yields decreased with increasing residence time and they disappeared after a sufficient residence time. This suggests that catalytic cracking achieved complete deoxygenation of triglycerides. Among the oxygenates, the yield of lauric acid was remarkably high at a short residence time and decreased greatly with increasing residence time, indicating that fatty acids are initially produced by catalytic cracking of saturated triglycerides and are then deoxygenated to hydrocarbons via ketones and aldehydes. Oxygenate formation was hardly observed at a residence time of around 5 s, indicating that deoxygenation was almost complete (Figure 3a,b). However, the yields of CO2 and CO at this residence time were only 5.2 and 3.4 wt %, respectively. These weight-based yields of CO2 and CO correspond to production of only 1.4 mol of CO2 (0.69 mol) plus CO (0.71 mol) from 1 mol of trilaurin (Table 3), indicating that the
therefore much slower than that of unsaturated hydrocarbons. Furthermore, our results suggest that unsaturated fatty acids also accelerate the deoxygenation of triglycerides in catalytic cracking reactions. The deoxygenation mechanism and the effects of unsaturated fatty acids on the mechanism are discussed in the following sections. Figure 2 shows the yields of hydrocarbons with different carbon numbers from the catalytic cracking of coconut oil and sunflower oil. The formation of unsaturated hydrocarbons such as light olefins (propylene and butene) and monocyclic aromatic hydrocarbons was observed in both cases. This shows that catalytic cracking of triglycerides competes with hydrocracking, which produces mainly saturated hydrocarbons and requires further reforming to produce unsaturated hydrocarbons. The reaction products from the coconut oil contained high yields of normal paraffins (n-paraffins) with carbon numbers 11, 13, and 15. The data in Table 1 show that the coconut oil consisted mainly of saturated fatty acids with carbon numbers 12, 14, and 16. The composition of the reaction products from coconut oil cracking therefore reflected the fatty acid composition of the reactant, i.e., n-paraffins were produced that were one carbon atom shorter than the fatty acids in the reactant. Correlations between the fatty acid composition of the triglyceride feedstock and the n-paraffins yields were also observed by Boocock et al. in the catalytic cracking of coconut oil on activated alumina catalysts.35 Here, the formation of higher paraffins reflecting the fatty acid composition of the reactant is a result of decomposition of the ester bonds between the fatty acid and the glycerol backbone. This suggests that in the catalytic cracking of saturated triglycerides, ester bond decomposition is faster than cracking of the carbon chains of the fatty acids. In contrast, the formation of higher paraffins or olefins reflecting the fatty acid composition of the reactant was hardly observed in sunflower oil cracking. This suggests that cracking of the unsaturated bonds in the fatty acid is as fast as, or faster than, decomposition of the ester bonds; this is consistent with a previous report.36 3.2. Catalytic Cracking and Deoxygenation of Saturated Triglycerides. The catalytic cracking of trilaurin, which is a model saturated triglyceride consisting of C12 fatty acids, was investigated to clarify the deoxygenation reaction mechanism in triglyceride cracking. The composition of the reaction product from trilaurin cracking was similar to that from coconut oil cracking; the main reaction products were hydrocarbons; CO2, CO, H2O, coke, and some oxygenates were also produced. The yields of hydrocarbons, CO2, CO, and
Table 3. Yields of Oxygen-Containing Products from Catalytic Cracking of Trilaurina Weight-based yield (wt %) Oxygen-based yield (O%) Carbon-based yield (C%) Mole-based yield (mol/molfeed) a
Oxygenates
CO2
CO
