Yield Of C5 Research Articles

Stability of an acid activated carbon based bifunctional catalyst for the raw bio-oil hydrodeoxygenation

The performance (activity, selectivity and stability) of a Pt-Pd catalyst supported on a phosphorus-containing activated carbon (ACP) has been studied in the hydrodeoxygenation (HDO) of raw bio-oil, and compared with another bifunctional catalyst prepared with a FCC (Fluid Catalytic Cracking) catalyst as acid support. Experiments have been carried out in a fixed bed reactor under the following conditions: 400–450°C; 65bar; space time, 0.18gcat hg−1bio-oil; H2:bio-oil ratio, 20cm3H2 (STP) cm−3bio-oil; time on stream, 0–10h. The catalyst reaches a pseudo-steady state at 450°C after 6h of time on stream, preserving a constant activity as a consequence of the simultaneous formation and hydrocracking of the deposited coke. In these conditions, the yield of C5+ hydrocarbons is 20wt%. This organic liquid fraction mainly contains aromatics, and thus, it may require an additional mild hydrocracking treatment for its valorization as fuel. On the other hand, the gas fraction obtained can be used directly as fuel, and the aqueous liquid fraction (with a high concentration of methanol, 58wt%) is interesting as co-feedstock with methanol in a methanol to olefins (MTO) unit.

Determination of pyrolysis behavior of brown coal in a pressurized drop tube reactor

Pyrolysis of a pulverized German brown coal was investigated using a new high pressurized drop tube reactor. Influence of temperature (600, 700, 800 °C), pressure (25, 60 bar (g)) as well as residence time (variation of heated reactor length: 500, 1500, 2500 mm) on pyrolysis product yields as well as char and gas composition were evaluated. Particle heating and residence times of gas and particle in the heated reactor section were calculated based on the obtained data. To trace the pyrolysis progress during particle drop in the reactor tube gas sampling over reactor height was done. A good reactor performance and reliable results for the pyrolysis experiments could be obtained for the new reactor equipment. Only a slight pressure influence on product yields, char composition, and gas composition was found, which was contrary at the different temperatures. This indicates competing reactions taking place at the given conditions. Gas species evolution over the reactor height is mainly promoted by rising temperatures. The long gas residence times in the reactor and the obtained CH4, H2, and C2 and C3 hydrocarbon yields are a result of secondary cracking of tar and gaseous hydrocarbons at temperatures above 600 °C. Furthermore, it was found, that heterogeneous gasification reactions take place at higher temperatures as well. Comparison between thermogravimetric experiments in “drop-in” mode and the DTR results show significant differences attributed to heat transfer limitations in the particle bulk (TGA) and to the long gas residence times (78–368 s) in the drop tube reactor.

Effect of extrusion conditions and hydrolysis with fiber-degrading enzymes on the production of C5 and C6 sugars from brewers’ spent grain for bioethanol production

The bioconversion of brewers’ spent grain into bioethanol was investigated in the present study using thermoplastic extrusion and the use of fiber degrading enzymes. The extrusion conditions i.e. tempering moisture, screws speed, and temperature of last zone of the barrel were taken into account in order to optimize the yield of C5 and C6 sugars during the subsequent enzymatic hydrolysis step of the fibers. The most important variable that affected the sugar yield was the extrusion temperature, followed by the screws speed. The best extrusion conditions were 20% tempering moisture, 200 rpm and 50 °C. No enzymatic and yeast inhibitors were detected in any of the enzymatically-treated fiber hydrolyzates. The fermentation resulted in 5.43 mL bioethanol per 100g of extruded brewers’ spent grain (dry weight basis). The only sugar consumed was glucose. The free amino nitrogen amount quantified in the hydrolyzates was as low as >20 mg L-1, negatively affecting sugars consumption during the fermentation and consequently the ethanol yield.

Fischer-Tropsch synthesis catalysts for the production of liquid fuels from various raw materials

The properties of cobalt catalysts for the Fischer-Tropsch synthesis used in XTL processes (the conversion of any organic raw materials into liquid hydrocarbons) are considered. It is shown that the catalysts used for the production of synthetic petroleum are characterized by a relatively low activity in polymerization reactions, and they make it possible to obtain hydrocarbon mixtures with the concentration of solid paraffins no higher than 10%. The catalysts used for conducting the synthesis of middle oil distillates are characterized by high polymerizing activity (alpha of 0.9 or higher) and by the high yields of C5+ hydrocarbons.

Antimicrobial and Antioxidant Activities and Effect of 1-Hexadecene Addition on Palmarumycin C2 and C3 Yields in Liquid Culture of Endophytic Fungus Berkleasmium sp. Dzf12

Two spirobisnaphthalenes, namely palmarumycins C2 and C3, were isolated from cultures of the endophytic fungus Berkleasmium sp. Dzf12 after treatment with 1-hexadecene. After addition of 1-hexadecene at 10% to the medium on day 6 of culture, the maximal yields of palmarumycins C2 and C3 were obtained as 0.40 g/L and 1.19 g/L, which were 40.00 fold and 59.50 fold higher, respectively, in comparison with those of the control (0.01 g/L and 0.02 g/L). The results indicated that addition of 1-hexadecene can be an effective strategy for enhancing the production of palmarumycins C2 and C3 in liquid culture of endophytic fungus Berkleasmium sp. Dzf12. Palmarumycin C3 exhibited stronger antimicrobial and antioxidant activities than palmarumycin C2.

Steam electrolysis with simultaneous production of C2 hydrocarbons in a solid electrolyte cell

The production of hydrogen from steam electrolysis with simultaneous conversion of methane to C2 hydrocarbons was investigated. The reaction system was studied in a solid state oxygen ion (O2−) conducting cell at temperatures between 700 °C and 840 °C. Methane and steam, diluted in nitrogen, were introduced over the anode (Ag) and the cathode (Pt), respectively. When oxygen was electrochemically “pumped” from the cathode to the anode, steam was electrolyzed to produce gaseous H2 and CH4 was converted to C2H4, C2H6 and CO2. The conversion of methane and the C2 yield increased when a perovskite of the form SrZr0.95Y0.05O3−a (SZY) was placed on the anodic electrode to serve as a methane coupling catalyst. At the anode, C2 yields exceeding 7.6% were obtained, while an up to 65% H2 yield was achieved at the cathode.

Optimal operation of a membrane reactor network

In this contribution, the operation of a membrane reactor network (MRN) for the oxidative coupling of methane is optimized. Therefore, three reactors, a fixed bed reactor (FBR) and two packed bed‐membrane reactors, are modeled. For the (CPBMR), a two‐dimensional (2‐D) model is presented. This model incorporates radial diffusion and thermal conduction. In addition, two 10 cm long cooling segments for the CPBMR are implemented based on the idea of a fixed cooling temperature positioned outside the reactor shell. The model is discretized using a newly developed 2‐D orthogonal collocation on finite elements with a combination of Hermite for the radial and Lagrangian polynomials for the axial coordinate. Membrane thickness, feed compositions, temperatures at the inlet and for the cooling, diameters, and the amount of inert packing in the reactors are considered as decision variables. The optimization results in C2 yields of up to 40% with a selectivity in C2 products of more than 60%. The MRN consisting of an additional packed‐bed membrane reactor with an alternative feeding policy and a FBR shows a lower yield than the individual CPBMR. © 2013 American Institute of Chemical Engineers AIChE J, 60: 170–180, 2014

Directional synthesis of liquid higher olefins through catalytic transformation of bio‐oil

AbstractBACKGROUNDCatalytic transformation of bio‐oil into higher olefins can provide valuable bio‐fuels and chemicals used in the manufacture of high‐octane gasoline, detergents, plasticizers and other petrochemicals. This work explores the production of higher olefins from bio‐oil through catalytic cracking of bio‐oil along with light olefins oligomerization.RESULTSFor bio‐oil catalytic cracking, the olefins yield reached 43.8 C‐mol% with near‐complete bio‐oil conversion. The oxygenated organic compounds in bio‐oil go through deoxygenation, cracking and hydrogen transfer reactions and form light olefins over the zeolite acid sites. For the oligomerization of light olefins, the highest selectivity and yield of C5+ olefins over the LTGO catalyst reached 85.4 C‐mol% and 326.7 g kg−1cata h−1, respectively. Main products below 300°C were C6=—C12= olefins, originating from light olefin oligomerization. The influences of the reaction conditions were investigated in detail, and the reaction mechanism was addressed.CONCLUSIONBio‐oil can be catalytically converted to C2=–C4= light olefins over HZSM‐5, and further selectively transformed to C5+ high olefins via the oligomerization of light olefins over LTGO. The transformation of bio‐oil to higher olefins may be useful for the production of bio‐fuels and high value chemicals using renewable biomass. © 2013 Society of Chemical Industry

A comparison of co-current and counter-current modes for Fischer–Tropsch synthesis in two consecutive reactors of oxidative coupling of methane and Fischer–Tropsch

The results of three cases of two consecutive reactors are studied in two types of co-current and counter-current flow in second reactor where two consecutive reactors are oxidative coupling of methane (OCM) and Fischer–Tropsch (FT) reactors. FT reactor can be fixed bed or membrane fixed bed reactor with a hydrogen perm-selective membrane. Effect of CH4/O2 ratio, contact time, inlet temperature, and amount of N2 in OCM feed on C2 to C5+ hydrocarbons produced in FT reactor were studied. Results show that use of counter-current hydrogen-perm selective membrane FT reactor that sequenced after OCM reactor improves the C5+ yield as a desirable product and reduces the amount of CH4 and CO2 as byproducts of FT reactor in comparison to co-current and conventional reactor. This phenomenon can be explained with more H2 diffusion through the membrane and more CO conversion and more hydrocarbons productions, briefly. As compared to the conventional reactor, in co-current and counter-current reactors, yield of C5+ has increased almost 3% and 4% alternatively when using these systems.

Theoretical analysis of oxidative coupling of methane and Fischer Tropsch synthesis in two consecutive reactors: Comparison of fixed bed and membrane reactor

In this paper, theoretical performance of Fischer Tropsch (FT) synthesis is analyzed where its feed comes from an oxidative coupling of methane (OCM) reactor. In this model based analysis, two consecutive reactors are intended that first reactor is OCM and second reactor is FT and FT reactor performance is compared in two conditions of fixed bed and membrane reactor (MR). The parameters concerned, were CH4/O2 ratio, contact time, temperature, and amount of N2 in OCM feed. High CH4/O2 ratio gave low yield of C2+ in OCM due to insufficient oxygen, but favored FT reaction due to more yield of C5+ and other products. Therefore, it was concluded that production and yield of C5+ could be more by use of these configurations.

Enhanced catalytic methane coupling using novel ceramic foams with bimodal porosity

Monolithic reactor concepts are currently intensively discussed in the literature. For the oxidative coupling of methane relying on a balance of surface and gas phase reactions, such concepts have previously been claimed to have beneficial effects with respect to obtainable C2 yields. In order to verify the superior performance in the case of a foam catalyst, ceria and samaria foams were fabricated by a direct foaming process. In both cases, mechanically stable, homogeneous open-cell foams were obtained as revealed by 3D magnetic resonance imaging, Hg-porosimetry, and scanning electron microscopy. As a characteristic feature of the introduced foaming methodology the process resulted in bimodal pore size distributions, ensuring low pressure drops on the one hand and sufficiently large surface areas on the other hand. Oxidative coupling of methane was carried out over the samaria foams. It was possible to obtain C2 yields that were indeed higher than those obtained with the samaria powder, in contrast to honeycomb monoliths previously studied in the literature.

Low severity dilute-acid hydrolysis of sweet sorghum bagasse

Sweet sorghum is emerging as a promising energy crop in India, with potential for ethanol production both from the extracted juice and the bagasse residue. This work investigates the release of fermentable total sugars (TS) and formation of total degradation compounds (TDC) by dilute sulphuric acid hydrolysis of sweet sorghum bagasse from the genotype SSV 84. Hydrolysis was conducted at moderate temperatures (100°C and 121°C). The effect of pretreatment severity (measured by the combined severity factor, CS), particle size and substrate loading on the hydrolysate composition was examined. The kinetics of xylose, acetic acid and furfural formation was also studied. The maximum theoretical yield is 29.9g C5 sugars/100g bagasse on dry weight basis. Under the conditions of this study, 10% substrate loading in the CS range of 1.64–1.93 was optimal with C5 yield >22.3g/100g bagasse and efficiency (TS/TDC ratio) >8. Bagasse particle size reduction also resulted in a higher efficiency. SEM and FT-IR analysis of the solid residue confirmed disruption of the biomass structure and removal of functional groups associated with hemicelluloses and lignin. This study demonstrates that acid hydrolysis at moderate temperature has an advantage in terms of high sugars concentration vis-a-vis low degradation compounds formation.

Evaluation of maximum gasoline production of Fischer–Tropsch synthesis reactions in GTL technology: A discretized approach

In the present study, a new optimization procedure is applied on Fischer–Tropsch synthesis (FTS) reactions to maximize the production yield of gasoline (C5+). In this way, the conventional synthesis reactor has been discretized into some elements. For each element, the inlet temperature, the injected hydrogen and the removed water are considered as decision variables. Then, the optimum amount of these decision variables is defined by using the differential evolution (DE) algorithm as an optimization method. Five distinct discretized reactor (DR) models have been investigated: the optimum inlet temperature of each element in DR1, the optimum hydrogen injection into each element in DR2, the optimum water removal from each element in DR3, the simultaneous optimum inlet temperature and hydrogen injection in DR4 and the simultaneous optimum inlet temperature, hydrogen injection and water removal in DR5. In all of these models, the objective function was the production yield ofC5+ at the end of the reactor. The results of this theoretical study demonstrated that in comparison with conventional reactor (CR) the C5+ yield, in DR1–DR5 is increased up to 4.7, 46.7, 2.0, 54.2 and 57.7 percent respectively.

Fischer-Tropsch synthesis in presence of composite materials containing iron and cobalt nanoparticles

Fischer-Tropsch synthesis in a static catalyst bed and in a three-phase system in the presence of composite materials containing iron and cobalt particles in the nano-size range 30-60 nm is investigated. It is shown that in both process implementation methods the yield and selectivity of liquid hydrocarbon formation increase with iron content in the composite material. In this case, the catalysts exhibit higher activity in the static bed and greater selectivity in the three-phase system. In the static bed of the most active catalyst containing 44.4 % iron and 33.3 % cobalt, the yield of C5+ hydrocarbons was 103 g/m3.

Effect of a promoter on the properties of the 20% Co-M/CoAl x O y catalytic system in the synthesis of hydrocarbons from CO and H2

The 20% Co-M/CoAlxOy catalytic systems promoted with Ru, Pd, and Re, in which cobalt is not only an active component but also a constituent of the support, were studied in this work. The effects of the addition and concentration of a promoter on the catalytic properties of the resulting system in the synthesis of hydrocarbons from CO and H2 was studied. It was found that the introduction of rhenium into the composition of the 20% Co/CoAlxOy catalyst considerably increased the yield of C5+ hydrocarbons with a minimum methane formation in the synthesis of hydrocarbons from CO and H2.

Effect of Confinement in Carbon Nanotubes on the Activity of Fischer−Tropsch Iron Catalyst

Following our previous findings that confinement within carbon nanotubes (CNTs) can modify the redox properties of encapsulated iron oxides, we demonstrate here how this can affect the catalytic reactivity of iron catalysts in Fischer-Tropsch synthesis (FTS). The investigation, using in situ XRD under conditions close to the reaction conditions, reveals that the distribution of iron carbide and oxide phases is modulated in the CNT-confined system. The iron species encapsulated inside CNTs prefer to exist in a more reduced state, tending to form more iron carbides under the reaction conditions, which have been recognized to be essential to obtain high FTS activity. The relative ratio of the integral XRD peaks of iron carbide (Fe(x)C(y)) to oxide (FeO) is about 4.7 for the encapsulated iron catalyst in comparison to 2.4 for the iron catalyst dispersed on the outer walls of CNTs under the same conditions. This causes a remarkable modification of the catalytic performance. The yield of C5+ hydrocarbons over the encapsulated iron catalyst is twice that over iron catalyst outside CNTs and more than 6 times that over activated-carbon-supported iron catalyst. The catalytic activity enhancement is attributed to the effect of confinement of the iron catalyst within the CNT channels. As demonstrated by temperature-programmed reduction in H2 and in CO atmospheres, the reducibility of the iron species is significantly improved when they are confined. The ability to modify the redox properties via confinement in CNTs is expected to be of significance for many catalytic reactions, which are highly dependent on the redox state of the active components. Furthermore, diffusion and aggregation of the iron species through the reduction and reaction have been observed, but these are retarded inside CNTs due to the spatial restriction of the channels.

Isobutane/butene alkylation on sulfated alumina: Influence of sulfation condition on textural, structural and catalytic properties

Samples of sulfated alumina with different sulfate contents were prepared by treatment of γ-alumina with an aqueous solution of a sulfate precursor (sulfuric acid or ammonium sulfate). Under conditions where no catalyst deactivation was observed, it was found that yield of C5+ products as well as C5–C7 products selectivity increase as the sulfate content increases up to 23 wt.% and remain practically constant with further increase in sulfate content. Catalysts deactivation was studied at higher olefin WHSV and lower isoparaffin/olefin ratio in the feed. Increasing the sulfate content up to 14 wt.% led to an increase in activity. A reduction in activity was observed when the sulfate content increased further. Samples with similar sulfate content obtained from different sulfate precursors exhibited similar butenes conversion and product distributions under both conditions. The differences in texture of sulfated alumina catalysts prepared from different sources of sulfate were determined by nitrogen adsorption. Different sulfate species, the formation of which is influenced by the source and sulfate content, were detected by DTG. Formation of sulfate-containing phases on the samples with sulfate content of more than 8 wt.% was found by X-ray diffraction (XRD). The appearance of these phases resulted in a significant drop in surface area and pore volume.

Quantification of hydroxycarbonyls from OH-isoprene reactions.

Hydroxycarbonyls arising from OH-initiated reactions of isoprene have been quantified by the technique of a flow reactor coupled to proton-transfer reaction mass spectrometry (PTR-MS) detection. The yields of C5- and C4-hydroxycarbonyls are (19.3 +/- 6.1)% and (3.3 +/- 1.6)%, respectively, measured at a flow tube pressure of about 100 Torr and at a temperature of 298 +/- 2 K. A yield of (8.4 +/- 2.4)% is obtained for the unsaturated carbonyl C5H8O, confirming that internal OH addition represents the minor channel in the initial OH-isoprene reaction. The results show that those carbonyl compounds account for the most previously unquantified carbon, enabling the isoprene carbon closure. The study also reveals novel aspects of the delta-hydroxyalkoxy radical degradation mechanism, which is essential for modeling tropospheric O3 formation. In addition, this work demonstrates the application of PTR-MS for quantification of products of hydrocarbon reactions, which should have profound impacts on elucidation of the chemistry of atmospheric anthropogenic and biogenic hydrocarbons.

Microencapsulated methylrhenium trioxide (MTO)/H2O2 systems for the oxidation of cardanol derivatives

Abstract A convenient and efficient application of microencapsulated/methylrhenium trioxide (MTO) and MTO/pyridine systems for the selective oxidation of cardanol derivatives is reported. Environmentally friendly and low-cost H2O2 was used as the oxygen atom donor. The catalysts were stable systems for at least five recycling experiments. In the oxidation of C2 alkyl-substituted cardanol derivatives, high conversion and yields of the corresponding para-benzoquinones were obtained. By contrast, in the absence of the C2 substituent, an unprecedented oxidative degradation to di-γ-lactone derivative was observed.

Comparative Study on Oxygen Permeation and Oxidative Coupling of Methane on Disk-Shaped and Tubular Dense Ceramic Membrane Reactors

Oxygen permeation and oxidative coupling of methane (OCM) on fluorite-structured Bi1.5Y0.3Sm0.2O3-δ (BYS) membrane reactors of disk-shaped and tubular geometries were studied at high temperatures (800−900 °C). Their oxygen fluxes under an oxygen partial pressure gradient of air/helium are similar and in the range of (1−3) × 10-8 mol/cm2·s at 900 °C. The highest C2 yields obtained in the tubular and disk-shaped BYS membranes are 22% and 10.4%, respectively. The oxygen permeation fluxes through both the disk-shaped and tubular BYS membrane reactors under OCM reaction conditions are 1−2 orders of magnitude higher than those under oxygen permeation conditions with He as the purge. Oxygen permeation flux through the tubular BYS membrane is an order of magnitude smaller than that through the disk-shaped membrane under the OCM reaction conditions. The results show that the membrane geometry and downstream flow conditions have a significant effect on the reaction results. The tubular geometry gives more favorable results in terms of C2 yield and selectivity.