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Steam cracking is a fundamental application of olefin production which is the building block of petrochemical complex. Continuous efforts are being made to optimize the cracker performance by process-side optimization. The cracker furnace flue gas, which has a huge quantum of low-grade energy, is getting lost from the stack; a waste heat recovery system is being employed to generate ow-pressure steam. This also helps in the reduction of induced draft fan suction temperature. However, if there are no low-pressure steam consumers, the steam requires to be vented or partial heat recovery to be done. The lower heat recovery through waste heat recovery boiler restricts the cracking furnace throughput due to a higher suction temperature of the induced draft. A detailed steam network study has been done for a petrochemical complex having various downstream plants to maximize heat recovery as well as furnace throughput. For any equipment in question, to use a lower steam, it was a challenge to switch over from relatively higher-pressure steam to lower-pressure steam due to equipment design consideration as well as operating temperature requirement of any process. Different alternatives were thought of and evaluated based on process requirement, possibility of steam venting of other level steam, and cost of modifications. The outcome of this study has helped to utilize the low-pressure steam. The study indicated that for optimization of cracker performance, in addition to process side, there is a scope to improve on flue gas side operation also. [ABSTRACT FROM AUTHOR]

In this research, a global reaction model for the thermal cracking of China No.3 aviation kerosene was modeled based on experimental investigations under supercritical pressure. The result indicates that, when the conversion is lower than 50%, small molecules of products were generated nearly in a constant ratio and the selectivities of them were approximately identical. Therefore, a molecular kinetic model was developed using plug flow reactor model and an isothermal hypothesis. In order to estimate the kinetic parameters, a novel method of online density measuring was used to obtain the precise resident time. The reliability of this molecular kinetic model was validated through the comparison of experimental results with simulated values. [ABSTRACT FROM AUTHOR]

Based on the characteristics of maximizing iso-paraffins (MIP) process and industrial data, an 8-lump kinetic model for MIP process is developed. And the 47 kinetic parameters of the model are calculated by Runge-Kutta method and genetic algorithm. It is seen that kinetic parameters show good consistence with the reaction mechanism of catalytic cracking. The average relative errors between calculated values and real values of product distribution are all below 5%. Then the model is modified by 14-7-5 type of back propagation (BP) neural network. As a result, the product distribution can be predicted more accurately by the hybrid model. Therefore, the combination of lump model and neural network can provide a new direction for simulation and optimization for heavy oil catalytic cracking. [ABSTRACT FROM AUTHOR]

The catalytic cracking of isopropylbenzene was investigaded over hybrid ZSM-12/MCM-41 and HZSM-12/MCM-48 micro-mesoporous materials, in order to verify the effect of the acid site of the accessibility of mesoporous channels combined with the acid sites into the zeolite. The hybrid materials were synthesized by the hydrothermal method using the template mechanism. The obtained materials were characterized by X-ray diffraction and BET isotherms using nitrogen adsorption-desorption at 77 K. The X-ray diffraction patterns presented characteristic peaks of the microporous and mesoporous phases. These analysis revealed the formation of ordered hexagonal MCM-41 or cubic MCM-48 mesoporous phases, associated with the ZSM-12 structure. In order to generate acid sites, the materials were ion exchanged with ammonium chloride solution. The calcined hybrid materials were tested as catalyst for cracking of isopropyl-benzene, using a fixed bed reactor at 450 oC and nitrogen gas. The catalytic tests showed that the HZSM-12/AlMCM-41 and HZSM-12/MCM-48 hybrid materials have potential for use in cracking reactions, bening more active than the zeolite or the M41S alone. The catalytic activities of the hybrid materials can be associated with a synergistic effect between the acid sites present on the zeolitic phase and the mesoporous phase. In order to verify how the structure of the hybrid materials may affect and control their catalytic performances, the results were compared with HZSM-12 physically mixed with MCM-41 and MCM-48. [ABSTRACT FROM AUTHOR]

Petroleum coke is often shortened as pet coke. Petroleum coke or pet coke is a product obtained from oil of all kinds during the oil refining process. Petroleum coke is a carbon-rich solid originating from petroleum refining and is obtained by cracking process. Petroleum coke is a byproduct of the coking unit, a residual fuel upgrader. The coke quality depends on the crude oil processed in refinery. The mixture of oil, solids and water deposited at the bottom of the storage deposit is known as waste oil sludge. Oil sludge is one of the solid wastes produced in petroleum refinery and it is a complex emulsion composed of various petroleum hydrocarbons, heavy metals, solid particles, and water. As a result of the refining process of crude oil, the contaminated sludge is biodegraded and converted into waste products that damage the environment and human health. In the coke processing, the assessment of oil sludge fraction is based on the principle of heating to high temperatures and the removal of light fractions from the breakdown. If the oil sludge initially contains low levels of sulfur and metal, the resulting petroleum coke is then calcined before use. The high quality needle type coke produced on convenient conditions in the coking unit. [ABSTRACT FROM AUTHOR]

The thermal evolution of phytol in thecatalytic environmentsof reduction, montmorillonite catalysis and illite catalysis has been investigated. The results show the following: (1)Montmorillonite and illite facilitate the defunctionalization and further cracking of phytol. (2) Pristane and phytane can no longer serve as effect biomarkers at the high thermal evolution stage due to loss of thermostability. (3) Ratios of pristane/phytane greater than 1derive from reduction and montmorillonite catalysis environments. However, the ratio of pristane/phytane was less than 1 under the condition of illite catalysis, which has not been shown before. [ABSTRACT FROM PUBLISHER]

Wilbur Nelson introduced the concept of complexity factor in the 1960s to relate the performance level of refineries with different capabilities and processing technologies. Refinery complexity has been used for many years to describe the sophistication and capital intensity of refineries, but foundational issues and the limitations associated with the metric have not been examined. A more precise and rigorous approach to complexity factors is presented based on the application of cost functions. Two alternative formulations are introduced and compared to the traditional approach and lead to new descriptive statistics and insight. [ABSTRACT FROM PUBLISHER]

Gasification is a thermochemical process that converts carbon-based fuels into a clean synthesis gas (so-called syngas). The produced syngas can be used directly as a fuel to produce electricity in gas engines or an intermediate chemical for production of Dimethyl ether (DME), methanol (MeOH), and/or ethanol. In this work, an unsteady-state, kinetic model that is used to predict the gas composition and performance indicators in presence of dolomite was developed. Results showed a good performance for biomass gasification in presence of dolomite as a catalyst. It is also concluded that the tar destruction ratio (TDR) exhibits an increasing trend with increasing [CaMg (CO3)2]/[C] from 0.1 to 0.9 (mg/mg), while after that, the increase levels off. [ABSTRACT FROM AUTHOR]

Heavy oil is less expensive than light crude oil, but heavy oil is more expensive to obtain light oil products. Conventional light crude oil resources are decreasing, therefore heavy oil resources will be needed more in the future. There are huge differences from field to field for heavy oil deposits. In terms of final productive use, heavy oil is considered as an unconventional resource. Heavy oil upgrading depends on four important factors: catalyst selection, heavy oil classification, process design, and production economics. Heavy and extra-heavy oils are unconventional reservoirs of oil. Globally, 21.3% of total oil reserves are heavy oil. Heavy oil is composed of long chain organic molecules called heavy hydrocarbons. The thermal degradation of the heavy hydrocarbons in heavy oil generates liquid and gaseous products. All kinds of heavy oils contain asphaltenes, and therefore are considered to be very dense material. The most similar technologies for upgrading of heavy oils are pyrolysis and catalytic pyrolysis, thermal and catalytic cracking, and hydrocracking. The amount of liquid products obtained from pyrolysis of heavy oil was dependent on the temperature and the catalyst. Pyrolytic oil contains highly valuable light hydrocarbons as gasoline and diesel components range. The constant increase in the use of crude oils has raised prices of the most common commercial conventional products and consequently seeking for new alternative petroleum resources, like some unconventional oil resources, becomes an interesting issue. The mass contents of gasoline, diesel, and heavy oil in the crude oil are 44.6%, 38.3%, and 17.1%, respectively. The gasoline yield from the heavy oil catalytic (Na2CO3) pyrolysis is higher than the diesel efficiency for all conditions. The yield of gasoline products increases with increasing pyrolysis temperature (from 230°C to 350°C) and percentage of catalyst (from 5% to 10%). The yields of gasoline-like product are from 21.5% to 39.1% in 5% catalytic run and from 32.5% to 42.5% in 10% catalytic run. The yields of diesel-like product are from 9.3% to 29.8% in 5% catalytic run and from 15.5% to 33.7% in 10% catalytic run. [ABSTRACT FROM AUTHOR]

The artificial neural network provides an effective way to handle a non-linear and strong coupled reaction system because of its strong nonlinear prediction and self-learning ability. A 19–24-4 type of back propagation (BP) neural network that can predict the product distribution of a fluid catalytic cracking maximizing iso-paraffin unit was established using 19 input variables including properties of feedstock and regenerated catalyst and operating variables. The influences of the operating variables on product distribution were simulated, and the operating variables were optimized to maximize gasoline (GS) yield by a genetic algorithm. The predicting results agreed well with the industrial data, and a significant improvement in the GS yield was gained. [ABSTRACT FROM PUBLISHER]

Based on the thermal simulation experiments of shale and crude oil samples, the amount of gas generated from kerogen and oil cracking during each geological period was calculated based on the chemical kinetic method. The results showed that the total amount of gas generated from the Niutitang Shale in Hy1 well is 49.00 m3/t, including gas generated from kerogen (17.76 m3/t) and gas generated from oil cracking (31.24 m3/t). The period of gas generated from kerogen is from the Cambrian to the Carboniferous with amount of gas generated value of 14.77 m3/t, which is mainly from the Lower Ordovician to the Middle Ordovician (510–470 Ma). The period of gas generated from oil cracking is from the Ordovician to the Triassic, and the main period of gas generated from oil cracking is from the Lower Devonian to the Upper Permian (410–250 Ma). The amounts of gas generated from oil cracking are 13.30 m3/t, 9.44 m3/t, and 3.77 m3/t in the Devonian, Carboniferous, and Permian, respectively. [ABSTRACT FROM AUTHOR]

The thermal methods consist of furnishing heat to the oil, reducing its viscosity. The electromagnetic heating for oil recovery is based on the transformation of electric energy into thermal energy. It happens through a direct interaction between the electromagnetic field and the electrically sensitive particles of the medium. The physical model applied to a reservoir is based on the principles of conservation of mass, conservation of energy, and conservation of movement in porous mediums, applied to the fluids and the solid phases. This study was based on reservoirs with characteristics similar to those found in the sedimentary basins of the Brazilian Northeast. The purpose of this work is to analyze the influence of the distinct cracking reactions and the coke formation of the different models during electromagnetic heating. [ABSTRACT FROM AUTHOR]

The condition of oil sand may change and produce new fractures at high temperature. However, the changing process of oil sand and its characteristics is not clear enough and still lacks certain experiments. Therefore, a new experiment is operated to study oil sand and its interlayers at high temperature. It is found that when the temperature reaches 180°C at first, fractures can be seen obviously along oil sand interlayers. After the oil sand is cooled and heated again, more cracks are produced vertical to the original fracture at 160°C. Different thicknesses and different lithologies are tested to produce cracks at different temperatures (100°C, 200°C, and 300°C). Cracks are produced suddenly when certain temperature thresholds are reached. These data are useful to study the heating process of oil sand in heavy oil reservoirs. [ABSTRACT FROM AUTHOR]

Catalytic and thermal cracking of polypropylene was performed in a batch reactor. Effect of hydrochloric acid activation on kaolin clay, effects of catalysts (acid-activated clays), promoter (5 wt% Ni), and cracking temperatures on the liquid oil yield were investigated. Results show optimized liquid yield (71.9%) obtained at 470°C with kaolin clay activated with 3 M HCl. Acid-activated catalysts were analyzed using XRD and the results reveal the reduction in peaks’ intensities. Weight loss of polypropylene was investigated by thermogravimetric analysis. FTIR and GCMS techniques were employed to analyze the liquid products. [ABSTRACT FROM PUBLISHER]

Disposal of waste plastic and excessive use of fossil fuels have caused environmental problems in the world. According to an estimate, more than 100 million tonnes plastics are produced every year and after their usage these plastics are discarded to become waste. Both plastic- and petroleum-derived fuels are hydrocarbons that contain the elements of carbon and hydrogen. The main difference between these hydrocarbons is that plastic molecules have longer carbon chains than those of LPG, petrol and diesel fuels. Therefore, it is possible to convert waste plastic into fuels. Pyrolysis is a prospective method to handle waste plastics. The purpose of this study is to explore the ability of different types of catalysts in conversion of plastic waste to low-emissive hydrocarbon fuel. Pyrolysis experiments were conducted using three different catalysts to check their ability in increasing the production. Catalytic degradation with potato peels yielded 74.52 wt% liquid fuel product. So far, the use of potato peels as a biocatalyst in pyrolysis process has not been reported. The pyrolysis oil was analyzed by GC/MS to determine its elemental composition. The liquid products obtained were compatible with international standards. Therefore, two main global problems such as problem of waste plastic management and problem of shortage of fuel are being tackled together. [ABSTRACT FROM PUBLISHER]

Use of warm asphalt mix has been recently receiving a great attention because it allows decreasing production and distribution temperatures about 30–40°C by either reducing bitumen viscosity or enhancing mixture performance. These mixes also have other advantages such as a low pollution, reduced fuel consumption, and more implementation seasons. Despite these benefits, there is a constant concern about the performance of these mixes under the conditions such as permanent deformation, fatigue cracking, and low-temperature cracking. In the present study, two types of bitumen modifiers including liquid additive and Sasobit were used to adjust rheological properties of bitumen. After conducting the required tests on bitumen specimens prepared using these two additives and comparing the results obtained from two common and Strategic Highway Research Program tests under aged and nonaged conditions, it was revealed that, considering the viscosity of bitumen, these additives improve bitumen performance at ambient temperatures. Besides, the results indicate the improvement in rutting criteria (G*/sinδ) and fatigue criterion (G*×sinδ). [ABSTRACT FROM AUTHOR]

Uniform distribution of liquid feed on fluidzed bed increase yield on valuable of products and improves operability in the process of fluid coking, and it is of crucial improtance to optimize the contact between the injected liquid and the bed solids. The moisture in fluidized bed is divided into three groups: (a) free moisture, (b) microagglomerates, and (c) macroagglomerates. The goal of this study was to develop a rapid and reliable experimental technique to assess the liquid-solid contact efficiency resulting from the injection of gas-atomized liquid feed. Immediately after the injection of liquid through an atomization nozzle, the triboelectric charges accumulated on the particles migrated to a grounded electrode through the paths offered by the conductive liquid. The methods based on the in situ measurements of the bed conductance varies with time, therefore, use to detect the liquid distribution on different agglomerates, and the air-liquid ratio effect of nozzle is also presented. [ABSTRACT FROM AUTHOR]

The electromagnetic heating for oil recovery is based on the transformation of electric energy into thermal energy. It happens through a direct interaction between the electromagnetic field and the electrically sensitive particles of the medium. There are different types of electromagnetic heating and the choice of the heating type depends on factors such as reservoir depth, geological heterogeneities, and electrical characteristics of the reservoir constituents. This study was based on reservoirs with characteristics similar to those found in the sedimentary basins of the Brazilian Northeast. The purpose of this work is to analyze the influence of the cracking reactions using electromagnetic heating and the influence of the fractures geometries in the reservoir model proposed. [ABSTRACT FROM PUBLISHER]

The authors aimed to determine the functional properties of binders and asphalt-mixtures modified with a liquid nano-organosilane additive. Hence, conventional and rheological tests of bitumen, Fourier transform infrared spectroscopy, and resilient modulus using indirect tensile test were applied. The results indicated that although this silane-based additive creates a hydrophobic layer over the surface of aggregates, which significantly improve the resistance of asphalt-mixtures against water damage; it has inconsiderable effect on rutting, fatigue, and elastic-response properties of both binders and asphalt mixtures. Furthermore, effect of it on low-temperature cracking of binders is still open for discussion. [ABSTRACT FROM AUTHOR]

In this research, the catalytic effect of four types of clays on crude oil low-temperature oxidation was analyzed in depth via static oxidation tube experiments and DTG-DTA tests. Results show that the LTO reactions are positively brought to a deeper degree by clays through lowering the energy requirement for the oxidation/cracking reactions, accelerating reaction rates, and depositing more coke-like fuel. All samples exhibit endothermic oxidation behavior and their energy requirements are proportional to mass loss rates. Based on catalytic study on the oxidation and thermokinetic behaviors of crude oil, a high degree of consistency is discovered between the two types of thermal analysis methods. [ABSTRACT FROM AUTHOR]

The hydrocracking of thermal cracking waxes obtained from pyrolysis of polyolefin at 360°C for 120 min has been studied using Ni-loaded molecular sieves catalysts. According to XRD, TPR, and BET data, the presence of nickel oxide did not seem to damage the crystalline framework of the catalytic supports. Hydrocracking experiments were carried out in a stirred autoclave reactor at 300°C for 120 min under 2.0 MPa of hydrogen. The results suggested the existence of a balance between the acid and metal function over bifunctional catalysts, which affects hydrogenation and hydroisomerization of thermal cracking waxes. Hydrocracking reactions took place extensively over mixture of Ni/HBeta and ZSM-5, leading toward higher fractions of gases (30.2%) and diesel (23.5%). The higher fractions of gasoline (33.5%) and lube base oil (19.0%) were obtained over mixture of Ni/HSAPO-11 and ZSM-5. In contrast, hydrocracking reaction occurred in a lower extent over mixture of Ni/NMCM-41 and ZSM-5, which produces lube base oil with lower pour point (–10°C), gasoline and diesel with lower bromine numbers (1.1 and 0.8 g Br2/100 g sample). The viscosity index of lube base oil was in the range of 131–171 over all three mixed catalysts. [ABSTRACT FROM AUTHOR]

The maximizing iso-paraffins (MIP) process, a family craft of fluid catalytic cracking process, is designed to reduce olefin content and increase isoparaffin and aromatic content in gasoline. The authors propose a method used to predict the gasoline yield of MIP process. The prediction model with 17 input variables is based on generalized regression neural network and adaptive boosting (adaboost) algorithm. The mean square error between predictive gasoline yield and actual yield is 2.46. [ABSTRACT FROM PUBLISHER]

Refineries’ production plan modeling with simple planning models such as the fixed yield planning models fail to reflect the operating conditions of the processing units. In this work, an integrated optimization strategy including production planning optimization, search of operating parameters and the operation optimization of fluidized catalytic cracking (FCC) units was proposed. The solution of optimal integration was validated by case studies of a monthly plan for a whole refinery, which included three FCC units. The results indicated that the optimization strategy was efficient in determining a practically executed optimal plan and corresponding operating conditions of FCC units. The integrated refinery planning model predicted higher profit and could provide the feasible or optimal FCC operation conditions. [ABSTRACT FROM PUBLISHER]

Jatropha oil was cracked over micoporous catalysts, such as HY, HZSM-5, and HMordenite, at the optimized conditions obtained over Hβ towards cracking of jatropha oil. The synthesized catalysts were characterized by X-ray diffraction, Brunauer-Emmett-Teller surface area analyzer, inductively coupled plasma, and temperature programmed desorption techniques. Among the microporous materials, HZSM-5 catalyst was found to be the best in terms of conversion (62%), selectivity towards green gasoline (50%), and less coke formation (0.8%) in the cracking of jatropha oil. Cracking of other oils, such as castor, neem, and pongamia, under the optimized conditions resulted in 82% conversion of castor oil; however, higher selectivity towards green gasoline (49%) was obtained in the cracking of pongamia oil. [ABSTRACT FROM PUBLISHER]

This paper investigates how small entrepreneurial firms in two peripheral regions developed by entering the oil and gas industry. The paper draws on previous studies related to the establishment of strategic alliances and emerging clusters and contributes to these research streams by examining the disadvantages of peripheral localization and small firm size. We use a longitudinal case study based on primary data consisting of 54 in-depth interviews conducted between 2007 and 2012 to illustrate that when large-scale oil and gas projects enter a peripheral region, oil companies can moderate local firms' disadvantages related to peripheral localization by actively facilitating relationships with established national firms. By facilitating such relationships and maintaining an active moderating role, strategic alliances and emerging cluster structures can arise. A cross-case analysis illustrates that the oil company had a decisive role in one of the two cases in two dimensions: its role as intermediary between local firms and national firms and its role in fostering the development of an emerging cluster structure by stimulating the establishment of new firms through the oil and gas project. In the second case, the oil company was unable to facilitate regional development. [ABSTRACT FROM AUTHOR]

The development of alternative sources for energy and chemicals, particularly the use of plant biomass as a renewable resource for fuel or chemical feed stocks, has received much recent attention. The resin (biocrude) obtained fromPinus roxburghii, a resinous tree, was investigated as a potential source for liquid fuels in a fluidized bed reactor. The feed was studied for yield conversion data under different catalysts to feed ratio at different temperatures. High conversions of biocrude to liquid fuels were observed with maximum middle distillates selectivity at a catalyst/oil ratio of 1.8 and reaction temperature of 460°C. Gas chromatography analysis results indicated that the middle distillates obtained by catalytic cracking ofP. roxburghiibiocrude has a normal distribution of carbon number with high values from C10–C18carbon atoms. [ABSTRACT FROM PUBLISHER]

Projecting future-year emission inventories in the oil and gas sector is complicated by the fact that there is a life cycle to the amount of production from individual wells and thus from well fields in aggregate. Here we present a method to account for that fact in support of regulatory policy development. This approach also has application to air quality modeling inventories by adding a second tier of refinement to the projection methodology. Currently, modeling studies account for the future decrease in emissions due to new regulations based on the year those regulations are scheduled to take effect. The addition of a year-by-year accounting of production decline provides a more accurate picture of emissions from older, uncontrolled sources. This proof of concept approach is focused solely on oil production; however, it could be used for the activity and components of natural gas production to compile a complete inventory for a given area. Implications: The Uinta Basin has unique atmospheric chemistry regimes during the winter that create ozone concentrations far exceeding those in the largest U.S. cities. This is also an area of complex regulatory authority shared among state, tribal, and federal agencies. This research accounts for regulations that are currently being implemented, and ties the effect of those regulations to emission factors used to estimate future-year inventories. This approach holds promise for future-year projections of oil and gas inventories for the region by providing a more representative life cycle of oil and gas emissions, including the disproportionate impact of older, uncontrolled sources. [ABSTRACT FROM AUTHOR]

The oxides adsorbent of NiO/ZnO-Al2O3-SiO2was prepared by a co-precipitation method. NiO/ZnO-SiO2-Al2O3is an effective adsorbent for reactive adsorption desulfurization of fluid catalytic cracking gasoline. The reaction conditions, such as reaction temperature, total pressure, weight hourly space velocity, and volume ratio of hydrogen to oil for desulfurization over NiO/ZnO-SiO2-Al2O3in a fixed-fluidized bed reactor were investigated. With the optimum conditions, the sulfur content of FCC gasoline can be decreased from 180 to 11.6 mg·L−1, and the loss of olefin content of gasoline product is 1.05%, the research octane number loss of gasoline product is only 1.3 unit. [ABSTRACT FROM PUBLISHER]

The preparation of α-olefins through steam cracking of wax from coal liquefaction was studied in this paper. Compare to the 54# petroleum wax having a highest α-olefin yield per pass of 21.9%, which is the widely used feed in the commercial α-olefin plants, the α-olefin yield per pass of coal wax was increased by 10.7% at the similar reaction conditions. This paper disclosed the different reaction performances from the viewpoints of feed composition and reaction network. The effects of the cracking temperature, the residence time, and the steam ratio on the product distributions of steam cracking were investigated. The conversion per pass of coal wax was 71.0%, and the α-olefin yield per pass was 34.7% at the optimal reaction conditions, in which the cracking temperature, the residence time and the steam ratio were 660°C, 3.7 sec, and 16%. The selectivity of α-olefins was 48.9%. The productivity can be evidently improved if using coal wax as feedstocks instead of petroleum wax. [ABSTRACT FROM AUTHOR]

The development of alternate sources of energy, particularly the use of plants as renewable sources for fuel, has received much attention recently. The potential of two indigenous arid land petrocrops,E. royleanaandE. neriifolia, as a source of hydrocarbon fuels was explored. Biocrudes extracted from these plant species were catalytically upgraded to liquid fuels using fluidized catalytic cracking. Naphtha fractions obtained by cracking of biocrudes were analyzed to give the detailed and group-wise distribution of paraffinic, isoparaffinic, oleofinic, naphthenic, and aromatic components. These naphtha fractions are similar in composition to the naphtha obtained from petroleum crudes. [ABSTRACT FROM PUBLISHER]

Lump kinetics models and reaction mechanism of fluid catalytic cracking (FCC) gasoline are introduced. Nine lump kinetics model, eight lump kinetics model, ten lump kinetics model, thirteen lump kinetics model, seventeen lump kinetics model, and twenty lump kinetics model have been put forward on the basis of lump theory and the reaction mechanism. In the network, the aromatization reaction species were first lumped into 9, 8, 10, 13, 17, and 20 parts, respectively. A mathematical method is first introduced to calculate a lump model of FCC gasoline. The results from experimental data are in accordance with the quantitative analytical conclusions drawn from the calculated data. [ABSTRACT FROM PUBLISHER]

The second largest source of propylene supplied for petrochemical application is from fluid catalytic cracking (FCC) units. The primary function of the FCC unit has typically been to produce gasoline. However, refiners have been taking advantage of opportunity to produce and recover more propylene from their FCC unit by increasing reaction severity via riser temperature, adding shape selective catalyst, and installing a propylene recovery unit (PRU). At a conventional FCC process propylene exists in the off gas of FCC and it is about 6 wt% of off gas by changing the FCC process parameter quantity of propylene in off gas can be more than 20 wt% by using ZSM-5 additives and increasing temperature The effects of operating parameters, such as reaction temperature, and ZSM-5 as FCC catalyst additive, on the distribution of the product and the yield of propylene were investigated on a bench-scale fluidized bed reactor. It is the aim of this work to perform an overall analysis of the yields and selectivity of hydrocarbons obtained in the vacuum gas-oil conversion over FCC and ZSM-5 catalysts. The effectiveness of ZSM-5 additive in the FCC process was investigated by doing experimental work in a bench-scale setup. The experiment data of off gas analysis showed that vacuum gas oil cracking at high reaction temperatures of 450–550°C increases the yield of propylene. Similar behavior is observed with the addition of 10–25 wt% ZSM-5 additive. The combination of the two effects (high temperature and ZSM-5 addition) makes the FCC unit an excellent source of light olefins for downstream petrochemical units. Higher FCC reactor temperatures (600–650°C) would not have positive effects for increasing propylene yield. [ABSTRACT FROM PUBLISHER]

A pentane-insoluble asphaltene was processed by thermal cracking, thermal hydrocracking, and catalytic hydrocracking in a microbatch reactor at 430°C. The experimental data of asphaltene conversion fit second-order kinetics adequately to give the apparent rate constants of 1.704 × 10−2, 2.435 × 10−2, and 9.360 × 10−2 wt frac−1 min−1 for the above three cracking processes, respectively. A three-lump kinetic model is proposed and solved to obtain rate constants of parallel reactions of asphaltenes to produce liquid oil (k1) and gas + coke (k3) and a consecutive reaction from liquid to gas + coke (k2). The value of k1 is 1.697 × 10−2, 2.430 × 10−2, and 9.355 × 10−2 wt frac−1 min−1; k2 is 3.605 × 10−2, 2.426 × 10−2, and 6.347 × 10−3 min−1; and k3 is 6.934 × 10−5, 5.416 × 10−5, and 4.803 × 10−5 wt frac−1 min−1 for asphaltenes thermal cracking, thermal hydrocracking, and catalytic hydrocracking, respectively. Analysis of selectivity shows that the catalytic hydrocracking process provides the highest liquid production, and the coking process provides the highest coke formation, as expected. An induction period of coke formation was found to increase from thermal cracking to thermal hydrocracking to catalytic hydrocracking process. [ABSTRACT FROM PUBLISHER]

A composition based model, constructed from the Monte Carlo method, for predicting ethylene, propylene, and butadiene yields in naphtha steam cracking process was developed. Seven structure vectors and 68 reaction rules have been designed to describe molecular composition and reactions. The Monte Carlo method was applied to simulate the cracking process. Seven kinds of model compounds, one kind of their mixtures, and straight-run naphtha have been used, respectively, as feedstock of the simulation at industry operating conditions to verify the validity of the proposed model. The results indicated that predicted data agreed well with the experimentally observed data. [ABSTRACT FROM AUTHOR]

The author proposes a variant of modernization of the catalytic processes of deep hydrocarbon conversion. The main difference and advantage of the proposed approach and technology is that raw materials, basically heavy materials that contain great amount of different harmful mixtures, do not directly interact with the catalyst. The suggested method has a great perspective and can be easily used in the petroleum industry, and may be much cheaper than the known processes of deep conversion. The use of natural and accompanying gas, which is in many cases burned in flares, to generate atomic hydrogen or light radicals makes it possible to minimize costs of the process of deep conversion. The technology is easy to operate and does not require heavy investment and operating costs. [ABSTRACT FROM AUTHOR]

Creep studies were carried out on 2.25Cr-1Mo steel base metal and its fusion-welded weldments at 823 K over the stress range 100-240 MPa. The weldment possessed lower creep rupture strength than the base metal due to type IV failure at the outer edge of the heat-affected zone (HAZ). Premature failure of the weldment was associated with pronounced creep cavitation accompanied with localized creep deformation in the soft intercritical region of the HAZ that was sandwiched between relatively higher creep deformation-resistant microstructural regions. The cavitation was associated with coarse intergranular precipitates in the intercritical region of the HAZ. The type IV cracking in the intercritical region of the HAZ was found to initiate deep inside the weldment and propagate towards the specimen surface. Finite element analysis of stress and strain distributions across the weldment was carried out considering the micro-mechanical strength inhomogeneity across it to explain the observed features of type IV cracking. The estimated higher von-Mises and principal stresses deep inside the intercritical region of the HAZ of the weldment led to the localized creep deformation and preferential cavity nucleation and growth, resulting in type IV failure of the weldment. The role of intergranular precipitate particles in the intercritical region of the HAZ in facilitating creep cavity nucleation by the exhaustion of creep ductility of the material close to the precipitate was corroborated from finite element analysis of stress and strain distribution around the precipitates. [ABSTRACT FROM AUTHOR]

This paper addresses a new feature parametric data of acoustic emission (AE) signals for crack monitoring based on the approximate entropy (ApEn). ApEn is a 'regularity statistic' that quantifies the unpredictability of fluctuations in a time series such as an instantaneous AE time series. Recently, ApEn has been developed as a statistic suited to quantify regularity and complexity, with potential applications to a wide variety of physiological and clinical time series data. Measures of AE variability and nonlinear complexity could be used as indications of crack initiation and/or propagation. A typical AE signal was simulated as a damped sinusoidal function with supplementary noise. ApEn values of such simulated signals were calculated and compared. The results show that AE time series containing many repetitive patterns have relatively low ApEn values. Simulated results were compared with those obtained experimentally through AE measurements obtained from cracks in steel tube tests. By analysing the complexity of these AE signals, we can conclude that ApEn can obviously distinguish the AE signals. Therefore, the ApEn values can contribute as prognostic parameters to complement traditional AE parameters. [ABSTRACT FROM AUTHOR]

As one of the nondestructive testing (NDT) techniques, pulsed eddy current (PEC) NDT usually uses the reflection-type probe, which consists of a pancake exciting coil for generation of the incident magnetic field and a pick-up coil or a solid-state magnetic field sensor for detecting the perturbed magnetic field due to the presence of defects in conductors. Normally, during the signal processing, the difference process is needed, which involves the subtraction of reference signals from the testing transient signals to enhance the sensitivity of detection. In this paper, a new PEC probe is proposed for the quantification of cracks. The probe has the self-differential characteristic, and thus the difference process is no longer required. The principle of the new probe is analysed firstly. Following that, the performance of the new probe is compared with that of a traditional PEC probe by simulations and experiments. The results show that the proposed PEC probe is valid and advantageous over conventional probes in terms of higher accuracy in quantification of defects. [ABSTRACT FROM AUTHOR]

It is widely recognized that naphtha steam crackers are the largest current source of propylene. The yield of propylene from a naphtha cracker is approximately half the yield of ethylene because ethylene has historically averaged a higher market price than propylene. Ethylene producers have primary built naphtha crackers to meet their ethylene demands and recovered propylene as a by-product. The availability of ethane at standard gas prices has attracted a large buildup of ethane-based steam cracker capacity, which produces very little propylene. As a result of buildup of ethane-based crackers, the propylene production rate from steam crackers is anticipated to fall, though the demand for propylene is expected to increase relative to the demand for ethylene. These market dynamics, if proven true, will result is a growing gap between propylene demands and propylene supplied from steam crackers, placing more emphasis and creating more opportunity for fluid catalytic cracking unit (FCC) units. The second largest source of propylene supplied for petrochemical application is from FCC units. The primary function of FCC units has typically been to produce gasoline. However, refiners have been taking advantage of the opportunity to produce and recover more propylene from FCC units by increasing the reaction severity via riser temperature, adding shape-selective catalyst, and installing propylene recovery units (PRUs). In this article propylene production methods are reviewed and comparisons between the methods are made. [ABSTRACT FROM AUTHOR]

The process of cracking dicyclopentadiene to produce cyclopentadiene using hydrogen as a carrier gas is investigated. This process has many advantages over using N2 or water vapor as a carrier gas for producing anhydrous polymerization level dicyclopentadiene. Factors, including cracking temperature, reaction time, and H2 to oil ratio, are studied. The conversion of dicyclopentadiene increases with the increasing of cracking temperature and reaction time; the yield of cyclopentadiene increases, and then drops a little with the increasing of reaction time. Optimal reaction conditions are as follows: suitable cracking temperature is 320°C, reaction time is 1 sec, and H2 to oil ratio is 50. Cracking temperature of the process is about 30°C lower than using N2 or water vapor as the carrier gas. At the optimal conditions, the conversion of dicyclopentadiene could reach 98%, while the yield of cyclopentadiene is 97%. The reaction kinetic model of the process is also studied, and the model could predict the conversion of dicyclopentadiene well. [ABSTRACT FROM AUTHOR]