Total Hydrocarbon Yield Research Articles

Hydrogenation of CO2 over Fe-K based catalysts in a fixed bed reactors at elevated pressure

Catalytic hydrogenation of CO2to produce hydrocarbons was conducted in a fixed bed reactor (1.6 cm-IDx60 cm-High). Fe-K based catalysts (KRICAT-A, B) were used for more than 850 hours to maintain CO2 conversion level up to 30 C-mol% in the fixed bed micro-reactor. Effects of operating variables on the CO2 conversion, hydrocarbon yield and its selectivity were investigated. The CO2 conversion and total hydrocarbon yield increased with increasing reaction temperature (250-325 °C), pressure (0.5-2.5 MPa) and H2/CO2 mol ratio (2-5); however, they decreased with increasing space velocity (1,000-4,000 ml/gcathr) in the reactor. The selectivities of liquid products increased with increasing reaction pressure; however, they decreased with increasing temperature, space velocity and H2/CO2 ratio. From the results of an experimental study, optimum operating conditions for the maximum yield of olefinic liquid products were found as T=315 °C, P=1.5 MPa, SV=2,000 ml/gcathr and H2/CO2 ratio=3 in the fixed bed reactor within these experimental conditions.

Co-production of dimethyl ether and methanol from CO2 hydrogenation: development of a stable hybrid catalyst

Efforts have been made aimed at the development of an active active and stable catalyst in the co-production of dimethyl ether (DME) and methanol from CO2–H2. The stabilities of ZSM-5 catalysts and Cu–ZnO-based methanol synthesis catalysts were investigated separately under water-rich conditions. By combining each stable catalyst, a relatively stable hybrid catalyst, Cu–ZnO–Al2O3–Cr2O3 + H–ZSM-5 (SiO2/Al2O3 = 80), has been developed. After losing about 5% of its original activity in 120 h, the catalyst exhibited no significant reduction in activity until 350 h in the reaction at 523 K and 3.0 MPa. Also, the catalytic activity was satisfactory at the steady state: the total yield of DME and methanol was higher than 26% with over 90% DME selectivity, but the total yield of hydrocarbons was lower than 0.25%. Copyright © 2001 John Wiley & Sons, Ltd.

Fischer-Tropsch synthesis over iron-based catalysts in a slurry reactor. Reaction rates, selectivities and implications for improving hydrocarbon productivity

A promoted iron Fischer-Tropsch synthesis catalyst is used in a slurry reactor to evaluate and compare the selectivity and yields of total hydrocarbons, light alkenes (C 2-C 3) and intermediate range (C 6-C 16) linear-α-alkenes for syngas derived from natural gas and coal. The catalyst has a high hydrocarbon yield of 0.6 g (of hydrocarbon)/h-g Fe at high CO conversions (>85%). The syngas derived from coal produces a slightly higher total hydrocarbon yield than natural gas-derived syngas, due to a lower reactor partial pressure of water which inhibits the Fischer-Tropsch reaction rate. The natural gas-derived syngas produces a lighter and more paraffinic hydrocarbon product than coal-derived syngas. The selectivity and yields of light alkenes as well as the intermediate range linear-α-alkenes decrease considerably with reaction time and CO conversion for syngas derived from both sources. The yields of these valuable products can be considerably improved by a lower single-pass reactor CO conversion with recycle of unconverted syngas or by using reactors in series. The syngas derived from coal produces a slightly lower ethylene and propylene yield, but a higher intermediate-range linear-a-alkene yield than that of natural gas-derived syngas.

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

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.

Release of covalently-bound alkane biomarkers in high yields from kerogen via catalytic hydropyrolysis

Fixed-bed pyrolysis of kerogens at high hydrogen pressures (> 10 MPa, hydropyrolysis) in the presence of a dispersed sulphided molybdenum catalyst gives rise to extremely high yields of dichloromethane (DCM)-soluble oil (> 65%). To illustrate the potential of this approach, the yields and conformations of the hopanes, steranes and methyl steranes released from Göynük oil shale (a type I kerogen) by hydropyrolysis after prior sequential extraction of the shale with DCM and pyridine and batchwise hydrogenation at 300°C (cf 520°C for hydropyrolysis) are reported here. The total yield of aliphatic hydrocarbons from hydropyrolysis represented ca 30% w/w of the kerogen's organic matter with yields of the C 29–C 32 17β(H), 21β(H)-hopanes being between three and ten times greater than those from DCM extraction and the milder hydrogenation treatment. The yields of the C 33–C 35 17β(H), 21β(H)-hopanes, not found in the DCM extracts and only minor constituents in normal pyrolysis oil, were again typically at least three times higher than from hydrogenation.

95/04688 Fixation of fine coal ash for road pavement

Hydropyrolysis of different types of high-boiling hydrocarbon fractions (straight-run distillates of different boiling range, dearomatized fractions and a hydrocracked fraction) was studied and the results were compared with pyrolysis (steam cracking) carried out under similar operating conditions. In all cases, a substantial increase in the yield of ethylene, a total yield of olefins and a total yield of C2 hydrocarbons, were observed. The possibility of limiting the amount of H2O by replacing it with H2, CH4 or N2, has been demonstrated. Hydropyrolysis was also shown to be effective in the case of a feedstock pretreated by dearomatization or hydrocracking.

95/04684 Effect of the quality coal-tar pitches on the physical properties of anodes

Hydropyrolysis of different types of high-boiling hydrocarbon fractions (straight-run distillates of different boiling range, dearomatized fractions and a hydrocracked fraction) was studied and the results were compared with pyrolysis (steam cracking) carried out under similar operating conditions. In all cases, a substantial increase in the yield of ethylene, a total yield of olefins and a total yield of C2 hydrocarbons, were observed. The possibility of limiting the amount of H2O by replacing it with H2, CH4 or N2, has been demonstrated. Hydropyrolysis was also shown to be effective in the case of a feedstock pretreated by dearomatization or hydrocracking.

Ethylene production from methane in a gas recycle electrocatalytic reactor separator

It was found that methane can be oxidatively coupled to ethylene with an ethylene yield up to 85% and a total C2 hydrocarbon yield up to 88%, in a novel gas-recycle electrocatalytic reactor-separator where the recycled gas passes continuously through a molecular sieve trap in the recycle loop. The molecular sieve traps and thus protects a controllable percentage of ethylene and ethane produced during each gas cycle. These products are obtained by subsequent heating of the trap. In this way we have obtained, using the batch operating mode of the recycle reactor, ethylene yields up to 85%, i.e. 88% selectivity to ethylene at 97% CH4 conversion.

Stepwise pyrolysis of macerals

Kerogen separates which consist predominantly of single maceral types at maturity levels lower than 0.7% vitrinite reflectance (R0) were pyrolysed in a single step and stepwise between 50 and 600°C. The total hydrocarbon yield and the yield of hydrocarbon gases (C1−C4) were determined along with the detailed composition of the gaseous fraction (C1−C4 alkanes and alkenes) and the C5+-fraction. The distribution of hydrocarbons, particularly in the C1−C3 range and the alkene/alkane ratio are useful as specific indicators for the various maceral types. The residue was analysed by reflected white light and fluorescence microscopy. The different types of reactive macerals i.e. algae, altered algae, particulate liptinites, amorphous liptinites and amorphous humic matter are transformed into particular types of inertinite. The reconstruction of the original maceral composition from its residue after katagenesis in a natural assemblage seems however difficult, due to the small amount of residue of the reactive macerals and the presence of original inertinite. Qualitative and quantitative data derived from these pyrolysis experiments may be useful on a comparative basis for the prediction of hydrocarbon generation by these maceral groups during katagenesis.

Global kinetic constants for thermal oxidative degradation of a cellulosic paper

Values of global kinetic constants for pyrolysis, thermal oxidative degradation, and char oxidation of a cellulosic paper were determined by a derivative thermal gravimetric study. The study was conducted at heating rates of 0.5, 1, 1.5, 3, and 5°C/min in ambient atmospheres of nitrogen, 0.28%, 1.08%, 5.2% oxygen concentrations, and air. Sample weight loss rate, concentrations of CO, CO 2, and H 2O in the degradation products, and oxygen consumption were continuously measured during the experiment. Values of activation energy, pre-exponential factor, orders of reaction, and yields of CO, CO 2, H 2O, total hydrocarbons, and char for each degradation reaction were derived from the results. Heat of reaction for each reaction was determined by differential scanning calorimetry. A comparison of the calculated CO, CO 2, H 2O, total hydrocarbons, sample weight loss rate, and oxygen consumption was made with the measured results using the derived kinetic constants and accuracy of the values of kinetic constants was discussed.

Hydrocarbon synthesis from carbon monoxide and hydrogen on impregnated cobalt catalysts II: Activity of 10% Co/Al 2O 3 and 10% Co/SiO 2 catalysts in Fischer-Tropsch synthesis

The results obtained in the investigation of the influence of the nature of the support and the temperature of pretreatment on the activity of cobalt catalysts in Fischer-Tropsch synthesis at atmospheric pressure are presented. Pretreatment by calcination in air was found to decrease cobalt reducibility and cobalt dispersion. The degree of reduction was higher with Co/SiO 2 than with Co/Al 2O 3 at all calcination temperatures. Except for the dried samples, the cobalt dispersions were found to be higher with Co/Al 2O 3. The variations in the catalytic properties of Co/Al 2O 3 and Co/SiO 2 in Fischer-Tropsch synthesis with the pretreatment temperature differ for both supports. When the calcination temperature was increased, the total hydrocarbon yield decreased over Co/SiO 2 catalysts and increased over Co/Al 2O 3 catalysts. The C 5+ fraction selectivities over Co/Al 2O 3 catalysts increased with the pretreatment temperature, while over Co/SiO 2 catalysts they remained practically constant. The resistance of cobalt catalysts to the action of air was higher with samples already used in Fischer-Tropsch synthesis than with freshly reduced ones. For freshly reduced Co/Al 2O 3 catalysts an increase of catalytic activity was found up to a certain level after repeated doses of air were passed through the catalyst bed. The nature of the oxide phases are thought to be responsible for the variation of catalytic properties. On the Co/SiO 2 catalyst surface, Co 3O 4 supposedly reduces the total hydrocarbon yield. In spite of the decrease of cobalt dispersion, the cobalt-support surface compounds cause an increase in the total hydrocarbon yield and the C 5+ fraction selectivity on the Co/Al 2O 3 catalysts.

Improved kerogen typing for petroleum source rock analysis

The chemical characterization of kerogen (typing) is a routine part of petroleum exploration programmes1. Traditionally, kerogen has been characterized on the basis of microscopy2 and bulk chemical methods3, procedures derived from the coal characterization literature1,4. These methods do not today, however, provide adequate resolution of the complex mixture of kerogen components encountered in source rocks from petroleum-bearing sedimentary basins5. Here we report an improved classification approach for kerogens at all maturity levels. The method is based on a quantitative pyrolysis–gas chromatography approach using a polymeric internal standard, polymethylstyrene, to directly determine the absolute concentrations of specific kerogen pyrolysis products. In particular, cross-plots of normal hydrocarbon, aromatic hydrocarbon and total hydrocarbon yields of kerogen pyrolysis are used to recognize eight separate nodes of kerogen composition

Potential of Pedilanthus tithymaloides as a petro-crop

Trials have been undertaken to study the comparative biomass and hydrocarbon production of seven different types of the plant Pedilanthus. After three years of growth the plants were cut and the resulting material subjected to acetone and benzene extraction. On the basis of the results obtained Pedilanthus tithymaloides var. cuculatus, P. tithymaloides var. variegatus I and P. tithymaloides (proper) are the most promising varieties for development as petro-crops, with potential for good biomass and total hydrocarbon yields.

Manganese oxide supported cobalt‐nickel catalysts for carbon monoxide hydrogenation

AbstractPerformances of manganese oxide‐supported cobalt, nickel, and their combinations of varying compositions have been investigated for CO hydrogenation to lower hydrocarbons using a fixed bed microreactor at atmospheric pressure and temperatures ranging from 525 to 575 K. While Co/MnO was found to exhibit high selectivity to olefins in the C2–C4 range, the total yield of hydrocarbons was low. Addition of nickel to cobalt gave a stable catalyst having improved hydrocarbon yields while still retaining good olefin selectivity. The effect of operating conditions on product distribution was studied. Lower space times and higher temperatures favored olefin selectivity. A comparison of Ni and Co catalysts on various support materials was made. MnO‐supported Co catalyst gave significantly higher olefin/paraffin ratio than that obtained using conventional supports such as SiO2 or Al2O3. It was found that Co/MnO exhibited high water‐gas shift activity, and suppressed hydrogen uptake due to strong metal‐support interaction which favored olefin formation. This can be explained on the basis of competitive adsorption of water and hydrogen on the same surface sites resulting in low hydrogenation activity but improved olefin selectivity.

Fast pyrolysis (ultrapyrolysis) of cellulose

A fast pyrolysis process, termed ultrapyrolysis, has been developed at the University of Western Ontario in order to exploit the high heating rates, short residence times high temperatures and rapid quenching, which are required to produce valuable non-equilibrium intermediates (i.e. ethylene and acetylene) from finely divided biomass. Hot solids(Thermo-for) are used to carry and transfer heat to the biomass particles in a very turbulent vortical contactor (Thermovortactor). This turbulence creates an ideal environment for fast thorough mixing and extremely rapid heat transfer. Cold solids (Cryofor) are then used to quickly quench the products. Trials with cellulose were conducted at temperatures between 750 and 900°C and residence times between 250 and 450 ms. Ethylene yields, expressed as a mass fraction of the product gas, varied from 6.8 to 8.2% for temperatures ranging from 750 to 900°C. The total hydrocarbon yield, also expressed as amass fraction of the product gas, was 18.8% at 900°C. The conversion of cellulose to a permanent non-condensible gaseous product was estimated to be 98% by mass at 900°C.

Preliminary Petroleum Source-Rock Assessment of Pre-Punta Gorda Rocks (Lowermost Cretaceous-Jurassic?) in South Florida: ABSTRACT

ABSTRACT Reconnaissance geochemical analyses (organic carbon (orgC) and Rock-Eval pyrolysis) were made of drill cuttings of pre-Punta Gorda rocks in seven widely scattered boreholes in South Florida to assess the petroleum source-rock potential. The rocks judged to have the best source characteristics, by virtue of their relatively higher orgC contents (0.4 to 3.2 percent) and total pyrolytic hydrocarbon yields (1 to 16 mg/g rock), occur chiefly in carbonates in the upper half of the Pumpkin Bay Formation (upper Coahuilan) and, to a lesser extent, in parts of the Lehigh Acres Formation (Trinity 'F' of Exxon). Geographically, the richest of these rocks are in the vicinity of the West Felda field and in the lower part of the Florida Keys. The rocks in the lower part of the Pumpkin Bay and underlying Bone Island (lower Coahuilan) and Wood River (Jurassic?) Formations have very low orgC contents (<0.3 percent) and low pyrolytic hydrocarbon yields (<0.3 mg/g rock). At face value, the oil potential is poor for pre-upper Pumpkin Bay rocks. Potential for natural gas, however, cannot be eliminated on the basis of insufficient organic matter even though the preliminary indications are not favorable. In light of a reported gas show in the Wood River Formation (at about 15,700 ft in the Phillips-Mobil 1-C Seminole well), the lower part of the pre-Punta Gorda section of South Florida may have some potential for gas, provided that other factors (porosity, permeability, traps) are favorable.

Composition of soluble organic matter in coals: relation to rank and liptinite fluorescence

Study of a series of twenty-six German high volatile bituminous B to low volatile bituminous coals of Upper Carboniferous age by recently refined analytical methods (‘flow-blending’ extraction, medium pressure liquid chromatography, HPLC, glass capillary gas chromatography and spectral fluorescence microscopy) reveals that yield and composition of soluble organic matter are strongly controlled by rank. In particular, the following points of inflection are noted in rank trends around 0.9% vitrinite reflectance: a maximum in yields of total soluble organic matter, aromatic hydrocarbons and n-alkanes; the most pronounced change in aromatic hydrocarbon composition; a trend reversal for pristane/ phytane ratios; a gradient change in the odd/even-predominance of long chain n-alkanes; appearance of a bimodal n-alkane distribution; and a sharp drop in concentration of individual n-, and isoprenoid alkanes. This discontinuity in rank trends around 0.9% Rm is interpreted to reflect a major change in reaction types, i.e. a shift from predominantly hydrocarbon generating to predominantly fragmentation reactions. Rank trends of maceral fluorescence exhibit the following pronounced changes over a similar but broader rank range: Different types of the maceral sporinite show a relatively abrupt shift of the fluorescence colour from yellow towards red between 0.8–0.9% Rm while up to about 1.0% Rm a sharp increase is recorded in the proportion of fluorescent vitrinite. This coincidence at a near-equal rank stage suggests a common cause for changes in yield and composition of the soluble organic matter and the maceral fluorescence of these coals.

Organic Composition of Some Upper Cretaceous Shale, Powder River Basin, Wyoming

The lower Upper Cretaceous strata in northeastern Wyoming, which have yielded major quantities of oil and gas, were sampled at boreholes in Converse, Johnson, and Weston Counties. Cores of noncalcareous shale of largely nearshore-marine origin were obtained from the Frontier Formation and the overlying Cody Shale at depths of 3,780.6 to 3,879.9 m in Converse County, near the axis of the Powder River basin, and at depths of less than 320 m in Johnson County, on the western flank of the basin. Cores of calcareous and noncalcareous shale representing offshore-marine and nearshore-marine environments were acquired from the Belle Fourche Shale, Greenhorn Formation, and Carlile Shale at depths of less than 270 m in Weston County, on the eastern flank of the Powder River basin. Analyses of the shale for organic carbon content, total pyrolytic hydrocarbon yield, volatile hydrocarbon content, temperature of maximum pyrolytic yield, and vitrinite reflectance indicate that the amount and character of the organic matter in the sampled rocks is related to the content of calcium carbonate, the depositional environment, and the burial depth of the strata. On the east flank of the Powder River basin, calcareous shale of offshore-marine origin contains abundant hydrogen-rich organic matter derived mainly from aquatic plants. Noncalcareous shale of largely nearshore-marine origin, on the west flank of the basin, locally contains significant hydrogen-poor organic matter derived mostly from land plants. The noncalcareous, nearshore-marine shale in the middle of the basin probably contained similar amounts of hydrogen-deficient organic matter prior to deep burial and thermal alteration. The calcareous shale in Weston County is a potentially rich source of oil and gas, but it is thermally immature and is in a very early stage of the hydrocarbon-generation process. The noncalcareous shale in Johnson County is a potential source rock for gas, but also is in an early stage of thermal alteration. In Converse County, the sampled beds are thermally mature and have generated hydrocarbons. The extent of this contribution of hydrocarbons to the commercial petroleum occurrences of the area can be inferred from the composition of the original organic matter in the beds. Furthermore, the degree of thermal alteration of the organic matter at these localities indicates that the depth of the sampled strata was never as great on the flanks of the Powder River basin as in the basin ce ter.

Generation and migration of light hydrocarbons (C 2C 7) in sedimentary basins

Sixty-five samples from selected source bed-type shale sequences from three exploration wells were analysed for yield and detailed composition of light hydrocarbons(C 2C 7) by a new hydrogen stripping/capillary gas chromatographic technique. In spite of low maturation levels (0.35–0.55% vitrinite reflectance), significant generation of ethane and propane was recognized in a Jurassic source bed sequence bearing hydrogen-poor kerogens. Light hydrocarbon generation in another and mature Jurassic source rock sequence is controlled by kerogen quality. Associated with a change from hydrogen-poor to hydrogen-rich kerogens, yields of total and most individual hydrocarbons exhibit orders-of-magnitude increases. At the same time, iso/n-alkane ratios for butanes, pentanes and heptanes decrease significantly. A study of an interbedded marine/nonmarine coal-bearing sequence of Upper Carboniferous age from the Ruhr area, West Germany, revealed that a marine shale unit in comparison to the adjacent coal seam is more prolific in generating n-alkanes of increasing molecular size. A case history for migration of light hydrocarbons by means of diffusion through shales is presented. In two shallow core holes in Campanian/Maastrichtian shales in West Greenland, upward diffusion of ethane to pentane range hydrocarbons is an active process within the near-surface 3 m interval. Diffusive losses within this interval amount to 99.8% for propane, 85.6% for n-butane and 38.9% for n-pentane.

Studies on the Structure of Peat Humic Acid (II)

Zinc-dust distillation has been used for elucidating the basic skeleton of organic compound having oxygen contaning groups such as hydroxyl, carboxyl and carbonyl gruop.In order to determine aromatic skeletons in chemical structure of peat humic acid, zinc-dust distillation was carried out at 500°C for 2 hr in a stream of hydrogen in compari-son with the results from model substances such as δ-lactone, phthalic acid, cumarin and 1, 2-naphthoquinone.Identification and semi-quantitative determination of polycyclic aromatic hydrocarbons in the reduction products from zinc-dust distillation were performed by using the gas chromatography and GC-MS techniques.The total yield of polycyclic hydrocarbons in the reduction products having anthracene, pyrene and perylene ring was 1.9 per cent based on the original peat humic acid. However, the yield of aromatic hydrocarbons containing 3 to 5 rings from peat humic acid was approx-imately equal to those from other model substances.From these results, it assumed that the peat humic acid has no polycyclic ring systems as the aromatic structure, and that the polycyclic aromatic hydrocarbons obtained from the peat humic acid by zinc-dust distillation was formed by rearrangement and condensation of oxygen containing structure under reaction conditions.