Production Of Light Hydrocarbons Research Articles

Pore fabrication of nano-ZSM-5 zeolite by internal desilication and its influence on the methanol to hydrocarbon reaction

A nano-ZSM-5 zeolite with average crystal size of 100nm was modified by internal desilication in NaOH solutions and exhibited great improvements in the catalyst lifetime and the yield of liquid hydrocarbons for the conversion of methanol to hydrocarbons (MTH). The microstructures of the treated nano-ZSM-5 zeolites were characterized by N2 adsorption, XRD, ICP-AES, TEM, TG and NH3–TPD techniques. It was found that the mesopores were introduced into nano-ZSM-5 crystals and the external surface area was increased from 72 to 115m2g−1 by internal desilication. With the increase of the treating time, these mesopores grew larger and more crowded, and subsequently they were connected with each other forming bigger cavities. Finally, a hollow structure was presented for nano-ZSM-5 crystals. Although great changes have been made in pore structure by this internal desilication, the specific MFI structure of the nano-ZSM-5 was still well maintained and the acidity was also obviously increased. This result was quite different from that obtained from desilication on the micro-ZSM-5. MTH reaction over treated nano-ZSM-5 catalyst was carried out in a fixed-bed tubular reactor at 400°C and WHSV of 4.7h−1 under 1MPa. The catalyst lifetime and the total production of the liquid hydrocarbon were increased by a factor of 2.2 and 2.5, respectively, as a consequence of the pore fabrication and the increased acidity. Production of light hydrocarbons was increased with increasing treating time of nano-ZSM-5. However, one thing to note is that the acidity of nano-ZSM-5 is vulnerable to damage during reaction and hydrothermal treatment process. Its regenerability and hydrothermal stability are not very satisfactory. More work is needed to improve the stability of acidity structure under the hydrothermal environment.

Influence of the spatial arrangement of catalyst components in the single-stage conversion of synthesis gas to gasoline

Aiming at the synthesis of gasoline in a single reaction stage, the conversion of synthesis gas was studied over several spatial arrangements of the catalyst components required for the synthesis of dimethyl ether and for the subsequent formation of hydrocarbons. At pressures of 40bar and temperatures between 270°C and 350°C, extruded catalyst bodies of Cu/ZnO/γ-alumina and of H-ZSM-5/γ-alumina were employed as well as trifunctional composite extrudates of Cu/ZnO/γ-alumina/H-ZSM-5. Using physical mixtures or trifunctional composite catalyst, carbon monoxide conversions can be achieved far above thermodynamic equilibrium levels because dimethyl ether is continuously withdrawn upon conversion to hydrocarbons. However, light hydrocarbon products are prevailing, and gasoline selectivities are very low. In sequential arrangements of copper- (up-flow) and zeolite-based (down-flow) catalysts, boosting of the CO conversion is not possible, but the product distribution is shifted to higher hydrocarbons. The highest gasoline yields were obtained when the copper and zeolite containing catalyst layers were divided in two different temperature zones operating at 270°C up-flow and at 350°C down-flow.

Production of Lighter Hydrocarbons by Steam-Assisted Catalytic Cracking of Heavy Oil over Silane-Treated Beta Zeolite

The surface of beta zeolite (SiO2/Al2O3 = 150) was modified using triphenyl silane in a liquid phase, and a series of catalysts was applied in cracking of heavy oil in the presence of steam. Steam reduces the coke formation, but at the same time, zeolite catalysts may be degraded in an aqueous environment at high temperatures. This problem was overcome using the surface-modified zeolite catalyst. The silane treatment of the zeolite surface not only reduced the coke amount but also stabilized the catalyst by increasing the hydrophobicity of the external surface of zeolite. Moreover, an atmospheric residue, which was used as a heavy oil feedstock, effectively decomposed into a lighter hydrocarbon (gasoline, kerosene, and gas oil) over silane-treated beta zeolite. Different reaction times were evaluated for modified beta zeolite in steam-assisted catalytic cracking of the atmospheric residue. The yield of the lighter hydrocarbon (C7–C35) was increased significantly up to 50.4 mol % in the product stream over...

Robust surface-modified Beta zeolite for selective production of lighter fuels by steam-assisted catalytic cracking from heavy oil

Production of lighter hydrocarbons were maximized by steam-assisted catalytic cracking of heavy oil over silane treated Beta catalysts. Steaming environment may cause dealumination of zeolites and affect the stability of zeolites. Herein, we improved the hydrophobicity and stability of the Beta zeolite catalyst (SiO2/Al2O3=150) by modifying its surface using triphenyl silane through vapor phase deposition technique. Parent Beta and silane treated Beta catalysts were tested in fixed-bed flow reactor for steam-assisted catalytic cracking of atmospheric residue. It was found that the modified Beta catalyst retained its crystallinity and phase purity after reaction. Moreover, coke formation was also reduced significantly over silane treated Beta catalysts. This indicates the increase in the stability of catalysts. Furthermore, the yields of gases, gasoline (C7–C13) and gas oil (C14–C20) over a silane treated Beta zeolite catalyst were 11.6mol%, 55.7mol% and 3.7mol% respectively for 2h reaction time.

Effects of Catalyst Preparation on Hydrocarbon Product Distribution in Hydrocracking of the Fischer-Tropsch Product with Low Pt-Loaded Catalysts

For the effective production of hydrocarbon liquid fuel in the hydrocracking of the Fischer-Tropsch (FT) product, the catalytic performance of Pt-loaded catalysts with low Pt content was investigated using an autoclave at 250 °C, an initial H2 pressure of 0.5 MPa, and a reaction time of 1 h. A screening study using Pt-loaded catalysts with a Pt content of 0.1 wt. % indicated that zeolite supports were more favorable for jet fuel (carbon numbers 9–15) production than amorphous oxide supports. The small particle size of the supported Pt particles and the high amount of medium acid sites for the supports led to higher performance of the Pt-loaded zeolite catalysts. In the hydrocracking reaction over Pt catalysts using the zeolite support with the high amount of medium acid sites, the yields of the corresponding jet fuel at 0.02 and 0.1 wt. % were almost the same. Pt-loaded catalysts with a Pt content of 0.02 wt. % were prepared using water-in-oil (w/o) microemulsions and their particle size was controlled between 1.0 and 2.6 nm. While the yield of the corresponding jet fuel was independent of Pt particle size, smaller Pt particles typically promoted the production of lighter hydrocarbons.

Effect of binary mixture of waste plastics on the thermal behavior of pyrolysis process

Waste plastic is non‐biodegradable material that does not decompose naturally for a long time. The pyrolysis process is a reliable method to decompose plastic wastes, which involves breaking of the heavy carbon chains and convert to light hydrocarbons. The light hydrocarbon products can be used as fuel to power vehicles and power stations. Pyrolysis experiment was conducted using thermogravimetric analysis (TGA)/DSC equipment for different types of non‐recyclable waste plastics: PET, HDPE, LDPE, PP, PS foam, and PS rigid. Investigations have been done to study the effect of binary mixture composition of PP and HDPE on pyrolysis behavior. Interactions between the plastics have been found to occur at the mixture composition range of 20–80 wt %. The decomposition rates of the individual plastics enhanced after the binary mixing of the different types of plastics. It was also found that secondary reaction occurred when mixing two types of plastics. The activation energy of the first step pyrolysis reaction is also higher than the secondary reaction. Overall, the activation energy of the pyrolysis reaction is decreased by 55% at the range of 20–80 wt % of binary mixture composition. © 2015 American Institute of Chemical Engineers Environ Prog, 34: 1113–1119, 2015

A study about the contribution of the α-β phase transition of quartz to thermal cycle damage of a refractory used in fluidized catalytic cracking units

The deterioration of refractories used in fluidized catalytic cracking units (FCC-units) is responsible for high costs of maintenance for the petrochemical industry. This is commonly associated with coke deposition during the production of light hydrocarbons. However, other mechanisms responsible for causing damage may also occur, such as the generation of cracks by expansive phase transition. The aim of the work herein was to study the contribution of the a-b phase transition of quartz particles to the deterioration of a commercial aluminosilicate refractory used in a riser by the means of slow thermal cycles. Such damage may occur if the working temperature of the equipment fluctuates around the a-b transition temperature (573 °C). The current study considered the material with and without coke impregnation to evaluate the combined effect of coke presence and phase transition. To evaluate the damage, it was used the Young's modulus as a function of temperature by applying the Impulse Excitation Technique under controlled atmosphere. An equipment recently developed by the authors research group was applied. Specimens were prepared and submitted to slow thermal cycles of temperatures up to 500 °C and up to 700 °C, with a heating rate of 2 °C/min. Part of the specimens was previously impregnated with coke by a reactor using propen. To complete the evaluation, characterization by X-ray diffraction, as well as by dilatometry and scanning electron microscopy were performed. The findings of this study showed that the presence of quartz particles determine the thermo-mechanical behaviour of the material, as well as the thermocycling damage resistance. In spite of the fact that the a-b phase transition stiffens the material during the heating stage, it increases the damage by slow thermal cycling. The coke impregnation increases the resistance to slow thermal cycles, however it decreases the resistance to the damage evolution.

Microwave pyrolysis of microalgae for high syngas production

The microwave induced pyrolysis of the microalgae Scenedesmus almeriensis and its extraction residue was carried out at 400 and 800°C. The results show that it is possible to obtain a gas fraction with a high content (c.a. 50vol.%) in H2 from both materials, regardless of the pyrolysis temperature. Furthermore, an outstanding syngas production and high gas yields were achieved. The maximum syngas concentration obtained was c.a. 94 vol.%, in the case of the pyrolysis of the residue at 800°C, indicating that the production of CO2 and light hydrocarbons was minimized. The same experiments were carried out in a conventional electric furnace in order to compare the products and yields obtained. It was found that microwave induced pyrolysis gives rise not only to higher gas yields but also to greater syngas and H2 production.

Effects of alkaline-earth metals on the structure, adsorption and catalytic behavior of iron-based Fischer–Tropsch synthesis catalysts

Effects of alkaline-earth metals (magnesium, calcium, strontium and barium) on the physico-chemical properties and Fischer–Tropsch synthesis (FTS) performances of precipitated Fe/SiO2 catalysts were investigated by N2 physisorption, laser Raman spectroscopy, FT-IR spectroscopy, in situ X-ray diffraction, Mössbauer effect spectroscopy, temperature programmed reduction or desorption and fixed-bed reactions. The characterization results indicated that alkaline-earth metals strengthened FeO bonds of Fe2O3 in as-prepared catalysts, which consequently inhibited the reduction of catalysts under H2 atmosphere. Mg and Ca suppress the carbonization of catalysts while Sr and Ba enhance the carbonization. The H2 adsorption was suppressed while the CO adsorption was enhanced by alkaline-earth metals. In the FTS reaction, alkaline-earth metals had no apparent influence on the CO conversion of catalysts, whereas they suppressed the formation of methane and enhanced the selectivities to olefin and higher molecular weight products. Among these alkaline-earth metals, Sr has the most pronounced influence on inhibiting the light hydrocarbon production. Furthermore, the increased Sr content can further restrain the formation of light hydrocarbons.

Synthesis of ionic liquids based on alkylimidazolium salts and their coal dissolution and dispersion properties

A series of new bis (imidazolium) cation-based ionic liquids, wherein two imidazole rings are tethered by alkyl ether chains (oxygen numbers) of different lengths, were prepared, and their coal dissolution and dispersion properties were studied. It was found these ionic liquids can be used to fragment, disperse, and partially dissolve micrometer-size coal particles by simply mixing ionic liquid/coal dispersions. Dissolution performances and light hydrocarbon production were found to be sensitively increased by increasing the lengths of alkyl ether chains between imidazolium rings.

Kinetics and Mechanism of Ni/Zeolite-Catalyzed Hydrocracking of Palm Oil into Bio-Fuel

Kinetics and mechanisms of Ni/zeolite-catalyzed cracking reaction of methyl ester palm oil (MEPO) were studied using a continuous flow-fixed bed reactor system at an atmospheric pressure. The catalyst was prepared by wet impregnation method with a solution of nickel nitrate hexahydrate as the precursor and zeolite as carrier. The characteristics of catalyst including active Ni metal content, crystallinity, total acidity, and porosity were evaluated. The reactions were performed with a varied hydrogen flow rate as a carrier gas as well as a reductant and reaction time. Liquid products were analyzed by GC. Analysis by GC-MS was only conducted on a product at hydrogen flow rate with the best conversion. It has been shown that the catalyst has a superior character for hydrocracking reactions of MEPO into green fuel. No considerable effect of hydrogen flow rate on the total conversion was observed. The tests showed that the kinetics of Ni/zeolite-catalyzed cracking reaction followed pseudo-first order kinetics. GC-MS analysis revealed the formation of light hydrocarbon products with C6-C8 of aliphatic and cyclic components without oxygenates. Distribution of the product indicated that the cracking reaction as well as the isomerization of the products of hydrocracking occurred. Thus, Ni/zeolite-catalyzed cracking involved cracking /hydrogenation, isomerization, cyclization, and deoxygenation.

Impact Analysis of Three Types of Insulation Materials Cold Heat Transfer in the Pipeline

The good and bad effects of cryogenic equipments and pipe cold directly affect the energy consumption of the device as well as light hydrocarbon production. Therefore, the low temperature pipeline laying cold layer is necessary to analyze the cold material impact on the structure of the heat transfer of cryogenic piping cold, it can be able to provide a scientific basis for the future related to the transformation of low-temperature device and pipes. Through the establishment of the low-temperature piping cold heat transfer model, analyzing the impact of different pipeline medium temperature, cold material under low temperature piping cold heat transfer. The results show that : (1) Under the conditions of the same cold thickness ,the temperature of the medium in the pipe decreases , the heat flux becomes large , the cold loss becomes larger ; ( 2 ) Same medium temperature and the thickness of the cold , the cold effect of the insulation material order LT> polyurethane> foam glass .

Study of the Production of Hydrogen and Light Hydrocarbons by Spark Discharges in Diesel, Kerosene, Gasoline, and Methane

Reforming liquid fuels into hydrogen and light hydrocarbons is desirable for improving the combustion characteristics of the fuels and the production of reducing agents for applications such as the removal of nitrogen oxides. In this study, diesel, kerosene, gasoline and methane were reformed by spark discharges between needle and plate electrodes at room temperature and atmospheric pressure. The gaseous products from liquid fuels comprised 65–70 % hydrogen and 30–35 % light hydrocarbons having two carbon atoms per molecule (i.e., C2s), or three carbon atoms per molecule (i.e., C3s). The product gases were 90 % hydrogen and 10 % C2s in the case of methane reforming. The energy efficiency for the production of gaseous products was highest in the case of gasoline at 3.8 mol/kWh, followed by kerosene, diesel and methane at 3.2, 3.0, and 2.4 mol/kWh, respectively. These results were found to be comparable to those reported by others for the reforming of pure hydrocarbons by plasmas in liquids. The liquid fuels turned black due to the formation of carbonaceous products, some of which could be filtered out as solid carbon particles, but others remained dissolved and imparted color to the treated liquid.

Catalytic carbonization of polypropylene by the combined catalysis of activated carbon with Ni2O3 into carbon nanotubes and its mechanism

A one-pot approach was established to prepare carbon nanotubes (CNTs) through the carbonization of polypropylene (PP) by the combined catalysts of activated carbon (AC) with Ni2O3. The combination of AC with Ni2O3 showed a synergistic catalysis on the catalytic conversion of PP to form CNTs. The effects of the content of AC and carbonization temperature on the yield of CNTs were studied. The morphology, phase structure and thermal stability of the obtained CNTs were analyzed by means of SEM, TEM, XRD, TGA and Raman. In this synergistic catalysis, the surface functional groups (especially carboxylic groups) of AC were proved to be the key factor. AC not only promoted the cracking of PP fragment radicals into light hydrocarbons and the dehydrogenation and aromatization of the resultant light hydrocarbons into aromatic compounds, but also promoted the formation of the intermediate aromatic compounds or polycyclic aromatic hydrocarbons (PAHs) from the reaction of light hydrocarbon products and aromatic compounds. Additionally, AC assisted in situ Ni catalyst (originated from the reduction of Ni2O3) catalyzing the dehydrogenation and aromatization of intermediate aromatic compounds or PAHs products to form CNTs. At last, a layer-by-layer assembled mechanism based on benzene rings for the growth of CNTs using PP as carbon source and combined AC/Ni2O3 as catalysts was proposed. This mechanism will help to understand the growth mechanism of CNTs using virgin or waste plastics as carbon sources. More importantly, this approach offers a new potential way for large-scale production of CNTs from waste plastics using cheap AC as a cocatalyst.

Efeito do tempo de exposição a uma atmosfera coqueificante na microestrutura e nas propriedades de um concreto refratário usado na indústria petroquímica

Os concretos refratários usados em unidades de craqueamento catalítico fluidizado (UFCC) podem sofrer deterioração pela deposição de coque durante o processo de produção de hidrocarbonetos leves, ocasionando a diminuição do tempo de funcionamento do reator e conseqüente perda financeira para as petroquímicas. Diversos estudos foram feitos, porém nenhum deles aponta conclusivamente para a parcela que esta deposição tem na deterioração do concreto, permanecendo a dúvida se ele é o responsável pelos danos observados macroscopicamente no riser de uma UFCC. Este trabalho visou estudar o efeito do tempo de exposição a uma atmosfera coqueificante sobre um concreto refratário anti-erosivo, classe C, buscando identificar mudanças nas propriedades físicas e microestruturais que evidenciem o mecanismo de degradação e que possam fornecer subsídios para análises conclusivas acerca do entendimento do fenômeno. Para isso, prepararam-se amostras de um concreto usado industrialmente em UFCC, submetidas a um processo de coqueificação forçado em reator piloto. Fixou-se a temperatura e a taxa de aquecimento em 540 ºC e 50 ºC/h, respectivamente, variando-se os tempos de exposição ao gás propeno em 10, 60, 120, 240 e 480 h. Os corpos de prova tiveram suas microestruturas caracterizadas via microscopia ótica e eletrônica de varredura e suas fases por difração de raios X. Outros ensaios complementares foram necessários para o entendimento do fenômeno. Os resultados mostraram que a superfície e a microestrutura do material gradativamente se impregnam de coque, que preenche os poros, as microtrincas e as trincas. Não foram encontradas evidências de microtrincamento em torno dos poros da matriz do concreto preenchidos com coque, porém os agregados apresentam algum tipo de deterioração com o tempo de exposição ao propeno, não necessariamente causados diretamente pelo coque.

Experimental investigation of hydrogen production through heavy naphtha cracking in pulsed DBD reactor

Abstract Cracking of heavy naphtha is studied experimentally in a nanosecond pulsed DBD plasma reactor. The system has been evaluated for instant production of light gaseous hydrocarbons in the range of C1–C3 and hydrogen via continuous hydrocarbons cracking at room temperature and atmospheric pressure. The effect of some process parameters such as reactor geometry/gap distance, carrier gas and feed flow rates have been considered on the reactor performance, experimentally. Results indicate that the less carrier gas and feed flow rates cause more energy efficiency. The maximum process efficiency is found for carrier gas and feed flow rates of 50 and 1 ml/min, respectively, which gets higher to 106.23 l/kWh for 11.50 W input power and 1.35 mm inner electrode diameter. Furthermore, results proof that for cracking process in DBD reactors there is an optimum diameter to maximize the process efficiency. For the reactor studied here, the optimum diameter of inner electrode is 2.68 mm. In this case energy efficiency of the process is 159.29 l/kWh. Results indicates that the hydrocarbon product distribution during the process is C2 > C1 ≫ C3 > C4.

Production of hydrogen and light hydrocarbons as a potential gaseous fuel from microwave-heated pyrolysis of waste automotive engine oil

Waste automotive engine oil was pyrolyzed in a continuous stirred bed reactor using microwave energy as the heat source; the yield and characteristics of the incondensable gaseous products are discussed. The recovered gases (41 wt% yield) were found to contain substantial concentrations of light aliphatic hydrocarbons (up to 86 vol.%) that could potentially be used as a chemical feedstock or a fuel source to power the process, or to be reformed to produce hydrogen for use as a second-generation fuel. Examination of the composition of the gases also showed the formation of H2 (up to 19 vol.%) and CO that could also be used as a valuable syngas (with a H2 + CO content of up to 35 vol.%). The high yield of gaseous hydrocarbons can be attributed to the unique heating mode and chemical environment present during microwave-heated pyrolysis. The use of a microwave-heated bed of particulate-carbon showed advantages in transforming waste oil into valuable gases. Hence an environmentally unfriendly waste material can be transformed into a useful resource and serves as an alternative source of hydrogen or hydrocarbon energy. The recovery of valuable gases shows advantage over traditional destructive approaches and suggests excellent potential for recycling problematic waste oil.

Multi-component optimisation for refinery hydrogen networks

Heavier crude oil, tighter environmental regulations and increased heavy-end upgrading in the petroleum industry are leading to the increased demand for hydrogen in oil refineries. Hence, hydrotreating and hydrocracking processes now play increasingly important roles in modern refineries. Refinery hydrogen networks are becoming more and more complicated as well. Therefore, optimisation of overall hydrogen networks is required to improve the hydrogen utilisation in oil refineries. Previous work over hydrogen management has developed methodologies for H 2 network optimisation, with a very simplistic assumption that all H 2 rich streams consist of H 2 and CH 4 only, which leads to a serious doubt of solution’s feasibility. To overcome the drawbacks in previous work, an improved modelling and optimisation approach has been developed. Light hydrocarbon production and integrated flash calculation are incorporated into a hydrogen consumer model. An optimisation framework is developed to solve the resulting NLP problem. A case study is carried out to demonstrate the effectiveness of the developed approach.

Condensation reactions of propanal over Ce xZr 1− xO 2 mixed oxide catalysts

Vapor phase condensation reactions of propanal were investigated over Ce x Zr 1− x O 2 mixed oxides as a model reaction to produce gasoline range molecules from short aldehydes found in bio-oil mixtures. Several operating parameters were investigated. These included the type of carrier gas used (H 2 or He) and the incorporation of acids and water in the feed. Propanal is converted to higher carbon chain oxygenates on Ce x Zr 1− x O 2 by two pathways, aldol condensation and ketonization. The major products of these condensation reactions include 3-pentanone, 2-methyl-2-pentenal, 2-methylpentanal, 3-heptanone and 4-methyl-3-heptanone. It is proposed that the primary intermediate for the ketonization path is a surface carboxylate. The presence of acids in the feed inhibits the aldol condensation pathway by competitive adsorption that reduces the aldehyde conversion. Water also promotes ketonization and inhibits aldol condensation by increasing the concentration of surface hydroxyl groups that enhance the formation of surface carboxylates with the aldehyde. Hydrogen enhances cracking and production of light oxygenates and hydrocarbons. The light oxygenates may in turn be reincorporated into the reaction path, giving secondary products. However, the hydrocarbons do not react further. Analysis of the fresh and spent catalysts by XPS showed varying degrees of reduction of the oxide under different operating conditions that were consistent with the reaction results. Changing the proportion of the parent oxides showed that increased Zr favored formation of aldol products while increased Ce favored ketonization. This occurs by shifting the balance of the acid–base properties of the active sites.

Valorization of Waste Agricultural Polyethylene Film by Sequential Pyrolysis and Catalytic Reforming

This paper deals with the potential of using sequential pyrolysis and catalytic reforming for the conversion of agriculture film waste into useful hydrocarbon products. The experiments were conducted in a two-step reaction system consisting of a pyrolytic batch reactor (450 °C) connected in series to a secondary fixed bed reactor where the organic vapors were reformed at temperatures between 425 and 475 °C. Two conventional zeolites (HZSM-5 and Beta) and a mesostructured aluminosilicate Al-MCM-41 were used as catalysts in the reforming stage. Conversion values were not affected by the temperature in the reforming stage and remained fairly constant in all the experiments (89−92 wt %). In the absence of catalyst, the process generated a high proportion of hydrocarbons in the gasoline (C5−C12) and diesel (>C13) range (between 51 and 56 wt % and between 18 and 19 wt %, respectively) and a consequently lower amount of light hydrocarbon products (between 17 and 23 wt %), all of which consisted essentially of a ...