Crude Oil Feedstock Research Articles

Development of computational approach for calculation of hydrogen solubility in hydrocarbons for treatment of petroleum

For hydrogenation process, knowing the solubility of hydrogen (H2) in hydrocarbons is critical to improve the efficiency of process. We investigated the H2 solubility computation in four heavy crude oil feedstocks using machine learning techniques. Temperature, pressure, and feedstock type were considered as the inputs to the models, while the hydrogen solubility was the sole response. Specifically, we employed three different models: Support Vector Regression (SVR), Gaussian process regression (GPR), and Bayesian ridge regression (BRR). To achieve the best performance, the hyper-parameters of these models optimized using the whale optimization algorithm (WOA). We evaluated the models using a dataset of solubility measurements in various feedstocks, and we compared their performance based on several metrics. Our results show that the WOA-SVR model tuned with WOA achieves the best performance overall, with a RMSE of 1.38 × 10−2 and an R-squared of 0.991. These findings suggest that machine learning techniques can provide accurate predictions of hydrogen solubility in different feedstocks, which could be useful in the development of hydrogen-related technologies. Besides, the solubility of hydrogen in the four heavy oil fractions are estimated in different ranges of temperatures and pressures of 150 °C–350 °C and 1.2 MPa–10.8 MPa, respectively.

Economic feasibility of plastic waste conversion to fuel using pyrolysis

Plastics that are difficult to mechanically recycle can be chemically recycled by pyrolysis into petrochemical feedstock that can be used either as fuel or as a starting material for chemicals or polymers. The objective of this study is to assess the economic feasibility of converting post-consumer plastics to fuel or oil using pyrolysis, and to assess the processing and market conditions required for a successful deployment of pyrolysis technologies. The economic feasibility of converting plastic waste to oil/fuel using pyrolysis is evaluated using as criteria the net present value (NPV) and internal rate of return (IRR). The Lang factor method is used to estimate the cost of the plant (capital and operating cost). Capital expenditures (CapEx), operating expenses (OpEx), and revenue generated by the sale of product are estimated. US market conditions (i.e., feedstock cost, feedstock transportation cost, volume of feedstock available, taxes, wages, tipping fees) are taken into account in estimating operational costs. The plants were evaluated at three scales: 30 tons per day (TPD), 60 TPD, and 100 TPD, each with the option of sourcing feedstock at the current market price (Case 1) or at no cost (Case 2). Investment decisions based on entity basis (unlevered NPV), show the plants can be profitable at scales higher than 60 TPD in both Case 1 and Case 2. However, on equity basis, using current market conditions for analysis, the 30 TPD plant has a negative NPV in both cases, and the 60 TPD and 100 TPD plans are profitable in Case 2 but not in Case 1. Profitability of plastic-to-fuel conversion using pyrolysis is influenced by crude oil prices, feedstock costs, CapEx and OpEx, discount rates, and operating hours.

Eight-lumped kinetic model for Fischer-Tropsch wax catalytic cracking and riser reactor simulation

Wax produced during Fischer-Tropsch synthesis (FTS) has no sulfur, nitrogen and aromatic contents and could be an attractive material to produce high quality transportation fuels by means of fluid catalytic cracking reaction. The kinetic modeling and riser reactor simulation are urgently needed. However, most of the current models in this field are based on crude oil feedstock which can not rigorously reflect the features of FTS wax catalytic cracking, especially the aromatization of the cracked light olefins for aromatic gasoline components. The effects of operating conditions on the catalytic cracking performance of FTS wax are investigated in a riser reactor with an industrial β-zeolite based catalyst. An eight-lumped (including paraffins, olefins, naphthenes and aromatics in gasoline, liquefied petroleum gas, dry gas, FTS wax and coke) kinetic model is developed for product selectivity description and riser reactor simulation in FTS wax catalytic cracking. The theoretical prediction is in good agreement with the experimental data. The modeling work is very helpful in reactor scale-up and operating condition optimization of the process.

Refinery production planning optimization under crude oil quality uncertainty

Current practice in refinery planning is to assume that the qualities of the crude oil feedstocks are known, even though they often vary. The uncertainty of the quality properties can significantly impact the profit of the refinery and needs to be considered in purchasing decisions. This work employs the product tri-section CDU model (Li et al. 2020) to build an accurate refinery model and determines the optimal crude selection by two-stage stochastic programming. The uncertainty of the crude oil quality properties is defined via the uncertainty of the TBP curves, which is described by the uncertain parameters of the beta functions approximating the TBP curves. The probabilistic scenarios are generated via random vector sampling method, leading to a relatively small number of scenarios required for the two-stage-stochastic programming model convergence. This enables us to determine the best crude oil choice, while requiring acceptable computational times, as illustrated by computational experiments.

Optimal design of flexible heat-integrated crude oil distillation units using surrogate models

The design of distillation columns often considers a given fixed feedstock and nominal operating conditions. Here we present an optimization-based approach for the optimal design of these units considering a flexible operation under a range of potential feedstocks. Our method combines an artificial neural network with a support vector machine to model the crude oil distillation unit. The artificial neural network model predicts the performance of the distillation unit for a given crude oil feedstock whilst the support vector machine classifier filters out infeasible design alternatives from the solution space (i.e., designs that are unlikely to converge when simulated using a rigorous model). The inputs to the artificial neural network include the column structural variables and operating conditions, whilst the outputs are process variables linked to the column performance. The artificial neural network models and support vector machines constructed for different crude oil feedstocks are integrated into a two-stage optimization framework in order to optimize the column structural variables and operating conditions, where the minimum utility demand is estimated using the pinch analysis. An effective solution strategy that combines stochastic and deterministic optimization algorithms is applied to search for economically viable and flexible design alternatives that can operate over a given range of crude oil feedstocks while satisfying the product quality specifications. The capabilities of the proposed approach are illustrated using an industrially-relevant case study, where we clearly show that the proposed approach can identify design alternatives capable of handling various feedstocks effectively.

In pursuit of environmentally friendly straws: a comparative life cycle assessment of five straw material options in South Africa

The increasing global concern surrounding plastic pollution has resulted in a spotlight being placed on major contributors. Straws have been identified as a top contributor in this regard leading to a global outcry against plastic straws. This has resulted in the increasing popularity of plastic straw material alternatives. This study compares the environmental impacts associated with five straw material options available in South Africa. The straw materials compared include disposable options (polypropylene, paper and polylactide) and reusable straws (glass and steel). Plastic straws were the only option which are locally produced from local materials, whereas glass and steel straws are manufactured from imported materials and paper and polylactide straws are imported. The functional unit was based on an annual straw consumption per capita, which equates to 36 disposable straws and 1 reusable straw. The impact assessment was conducted using the Recipe Midpoint (H) method, which took into consideration 18 impact categories. The potential marine pollution impacts were explored based on the leakage propensity of the material option coupled with its degradability. The paper straw was found to have lower climate change emissions than the plastic one, which was mainly caused by the performance of the material. In South Africa, coal is used as a primary feedstock for polypropylene production making it more carbon-intensive in comparison with polypropylene produced in Europe and the USA which is primarily from crude oil and/or natural gas feedstocks. Glass and steel straws would require 23–39 and 37–63 uses respectively to break even with climate change emissions associated with disposable options. Overall, material production was the major contributor to straw emissions. The relative contribution of transportation, including import, was more dependent on the transportation mode compared with distance. For reusable straws, the washing water temperature was found to notably influence emissions. At end-of-life, reusable straws were considered unlikely to enter the marine environments. Disposable straws were found to have a leakage rate of 38%, with paper being the only marine degradable material. Overall, paper straws had the least impacts in the majority of impact categories in comparison with other disposable options and glass was more favourable to steel. In terms of marine pollution, reusable straws were deemed to pose the least risk due to their unlikelihood to be polluted. Paper was associated with the least potential impacts of the disposal options, due to its degradability.

Narrowing the Gap for Bioplastic Use in Food Packaging: An Update.

Plastic production has outgrown most other man-made materials, with more than 90% being petroleum-based and nonbiodegradable. Packaging, primarily food packaging, consumes the most plastic and is the largest contributor to municipal solid waste. In addition, its dependence on crude oil feedstock makes the plastic industry unsustainable and renders plastic markets vulnerable to oil price volatility. Therefore, the development of bioalternatives to conventional plastics is now a priority of the food packaging industry. Bioplastics are polymers that are either biobased (fully or partially), or biodegradable, or both. This review aims to provide an insightful overview of the most recent research and development successes in bioplastic materials, focusing on food packaging applications. Bioplastics are compared to their conventional counterparts with respect to their mechanical, thermal, barrier, and processability properties. The gaps between bio- and conventional plastics in food packaging are elucidated. Potential avenues for improving bioplastic properties to broaden their food packaging applications are critically examined. Furthermore, two of the most controversial topics on bioplastic alternatives, sustainability assessment and their impact on the plastic waste management system, are discussed.

Exploiting the heteroskedasticity in measurement error to improve volatility predictions in oil and biofuel feedstock markets

We examine whether heteroskedasticity in measurement errors improves the volatility forecasting ability of the Heterogenous Autoregressive (HAR) model in crude oil and biofuel feedstock markets. We also examine the incremental explanatory power of jumps and the investor fear gauge (IFG) over heteroskedasticity in measurement errors in improving the volatility forecasting ability of the HAR model in each of these markets. For the in-sample evaluation, we find that exploiting the heteroskedasticity of measurement errors in the HAR model improves the model's goodness of fit (measured by adjusted R2) by up to 10% depending on the market. IFG has a significant incremental role over heteroskedasticity in measurement errors in improving the fit of the HAR model in both the crude oil and biofuel feedstock markets, while jumps have a significant incremental role in improving the fit of the HAR model in the crude oil market, but not the biofuel feedstock markets. For the out-of-sample forecasts, including regime switching improves volatility predictions in the corn and wheat markets across all forecasting horizons, while for the soybean market, including regime switching improves the performance of multi-step volatility forecasts. In the out-of-sample forecasts the best ranked models almost always include heteroskedasticity of measurement error and IFG.

Fouling Diagnosis of Pennsylvania Grade Crude Blended with Opportunity Crude Oils in a Refinery Crude Unit’s Hot Heat Exchanger Train

The continual decline in the quantity of legacy Pennsylvania grade crude oil coupled with recent volatile crude oil prices has prompted American Refining Group to start processing a wide variety of opportunity crudes to expand its crude oil feedstock slate to maintain profit margins. As opportunity crude usage increases, crude oil fouling and unexpected corrosion have become major issues in the refinery crude unit’s hot heat exchanger train (HHET) and other process units. Crude oil fouling in the refinery has resulted in increased energy consumption, reduced throughput, and more frequent shutdowns. In this work, fouling at the refinery crude unit HHET resulting from the impact of Pennsylvania grade crude blended with opportunity crude oils was investigated. Thermal and hydraulic fouling models were studied to detect changes in the fouling behavior of the crude unit’s hot heat exchanger train. Phase separation of crude oil to coke fouling mechanism was described in detail. Several crude oil fouling diagnos...

The causes of two-way U.S.–Brazil ethanol trade and the consequences for greenhouse gas emission

Abstract Biofuel policies in the U.S. and Brazil can influence two-way ethanol trade, in which the countries export to and import from each other simultaneously. A multi-market, multi-region partial equilibrium economic model is used to assess the interactions of the biofuel policies and markets of these two countries. The market effects are converted to greenhouse gas (GHG) emission effects using calculations that include the emissions associated with the transportation of ethanol between Brazil and the U.S. Results show that under certain conditions ethanol and feedstock producer prices decrease in a “No Renewable Fuel Standard (RFS)” scenario, while GHG emission could rise. If the RFS is maintained in the U.S., but Brazilian gasoline prices are allowed to move freely with rising global crude oil prices, then ethanol and feedstock prices increase and GHG emissions decrease as the use of ethanol increases. We find that two-way ethanol trade can have important, if moderate, GHG emission impacts.

Understanding premixed flame chemistry of gasoline fuels by comparing quantities of interest

Gasoline fuels are complex mixtures that vary in composition depending on crude oil feedstocks and refining processes. Gasoline combustion in high-speed spark ignition engines is governed by flame propagation, so understanding fuel composition effects on premixed flame chemistry is important. In this study, the combustion chemistry of low-pressure, burner-stabilized, premixed flames of two gasoline fuels was investigated under stoichiometric conditions. Flame speciation was conducted using vacuum-ultraviolet synchrotron photoionization time-of-flight molecular beam mass spectroscopy. Stable end-products, intermediate hydrocarbons, and free radicals were detected and quantified. In addition, several isomeric species in the reaction pool were distinguished and quantified with the help of the highly tunable synchrotron radiation. A comparison between the products of both flames is presented and the major differences are highlighted. Premixed flame numerical simulations were conducted using surrogate fuel kinetic models for each flame. Furthermore, a new approach was developed to elucidate the main discrepancies between experimental measurements and the numerical predictions by comparing quantities of interest.

ChemInform Abstract: Fluid Catalytic Cracking: Recent Developments on the Grand Old Lady of Zeolite Catalysis

AbstractReview: 183 refs.

Risk Analysis of Biofuels Industry for Aviation with Scenario‐Based Expert Elicitation

ABSTRACTThe aviation sector relies almost exclusively on petroleum‐derived fuels at the present time. Due to concerns including national security, long‐term availability of crude oil feedstock, and environmental impacts, there is an increasing interest in identifying alternatives to conventional jet fuel. Viable alternatives must meet a number of criteria, related to quality and quantity of supply, cost‐competitiveness, and environmental sustainability. Priorities for diverse industry initiatives for the development of a biojet fuel industry are influenced by uncertainties including environmental regulation, market prices of crude oil and refinery products, and competition from other industries. This work uses scenario‐based preferences to elicit and inform decision makers on the combinations of emergent and future conditions that are most impactful to the priorities for the industry. The analysis also reveals which initiatives are robust to evolving political, economic, and technological conditions, thus supporting decision‐making relevant to establishing a secure supply of biojet fuel. The method and its results are helpful to the generation of systems engineering requirements recognizing key sources of risk for an emerging industry.

Biofuel Producers and Oil Price Risks

In the deregulated fuels market, biofuels and fossil fuels are close competitors and substitutes. Thus, biofuel producers are subject to risks due to volatile crude oil and biofuels feedstock prices. This paper proposes a two-sector fuel market with competing oil refinery and biofuel sectors, calibrated for cases of gasoline/ethanol and diesel/biodiesel. The model suggests that ethanol and biodiesel plants will shut-down approximately 40% and 20% of the time, respectively. The skewness of profits is -0.32, in contrast to the 0.91 of feedstock prices. Several firm-level and policy-level options to manage crude oil price risks for biofuel producers are discussed further.

Catalytic Conversion of Triglycerides to Liquid Biofuels Through Transesterification, Cracking, and Hydrotreatment Processes

Biofuels derived from biomass have recently received much attention due to depleting petroleum resources, and increasing energy consumption and cost. Biodiesel is considered a first generation biofuel produced from well refined vegetable oils by transesterifying triglycerides with methanol. The biodiesel market is potentially very large and can be sold into the worldwide petroleum diesel market as a blended fuel. First generation biodiesel production technologies are based on homogeneous basic catalysts such as NaOH, KOH. However, the future direction is to develop heterogeneous catalytic process to simplify the present technologies. This article reviews current routes for the catalytic conversion of triglycerides into biofuels through transesterification, catalytic cracking, and hydrotreatment.Broadly, second generation biofuels are renewable fuels composed of hydrocarbons produced from refined oil, crude oil and waste feedstocks that have been catalytically cracked or hydrotreated. These hydrocarbons have a chemical structure similar to petroleum-based fuels and possess superior stability and storage properties in comparison with biodiesel. Present second generation biofuel research focuses on the usage of the commercialized fluid catalytic cracking (FCC) and hydrogenation catalysts used in petroleum industry and existing petroleum refinery infrastructure for creating renewable diesel fuel in order to avoid additional capital investment for new equipment. This review discusses the feedstocks, chemistry, catalysts, and challenges involved in the production of both the first and second generations of biofuels. Keywords: Triglyceride, heterogeneous catalyst, biofuels, transesterification, cracking, hydrotreatment, liquid, chemical structure, catalytic cracking, gasification, fermentation, BIODIESEL, Transesterification Chemistry, homogeneous catalysts

Life cycle cost and sensitivity analysis of palm biodiesel production

Increased biodiesel production is being proposed as one solution to the need to ease the impact of increased demand for crude oil and to reduce emissions of greenhouse gases. Despite this, biodiesel has yet to reach its full commercial potential, especially in the developing countries. Besides technical barriers, there are several nontechnical limiting factors which impede the development of biodiesel such as feedstock price, production cost, fossil fuel price and taxation policy. This study assesses these by undertaking a techno-economic and sensitivity analysis of biodiesel production in Malaysia, the second largest producer of crude palm oil feedstock. It was found that the life cycle cost for a 50ktons palm biodiesel production plant with an operating period of 20years is $665 million, yielding a payback period of 3.52years. The largest share is the feedstock cost which accounts for 79% of total production cost. Sensitivity analysis results indicate that the variation in feedstock price will significantly affect the life cycle cost for biodiesel production. One of the most important findings of this study is that biodiesel price is compatible with diesel fuel when a fiscal incentive and subsidy policy are implemented. For instance, biodiesel price with subsidies of $0.10/l and $0.18/l is compatible and lower than fossil diesel price at crude palm oil price of $1.05/kg or below. As a conclusion, further research on technical as well as nontechnical limitations for biodiesel production is needed before biodiesel can be fully utilized.

Production of biodiesel from crude neem oil feedstock and its emissions from internal combustion engines

This study investigates biodiesel production using crude neem oil having high acid value, as a feedstock. The effects of some operating variables were ascertained and its combustion performance was assessed in an internal combustion engine. Due to its high acid value, the neem oil was processed via two step acid – base transesterification process. The first step reduced the acid level to <2 mgKOH/g while the second step involved direct conversion to fatty acid methyl ester using 1% NaOH as catalyst. The lowest viscosity value was used as a proxy measure to determine the extent of the reaction. The results reveal the optimum conditions for biodiesel production to be ratio 1:6 of oil to methanol and 1.5 h reaction time. The viscosity at this condition was 5.53 cSt. The same procedure was repeated for NaOCH3 catalyst concentrations of 0.5, 0.75, 1 and 1.25%. The lowest viscosity of 6.79 cSt was recorded at both 1 and 1.25% catalyst concentrations. The fuel properties of the biodiesel compared favorably with the recommendation by the American Standard Testing Method. The emissions of different blends showed that neem biodiesel has lower emissions of CO and NO than petrol diesel but higher NOX. Thus, neem oil as non-edible oil can be a good renewable raw material for biodiesel production. Key words: Neem, biodiesel, internal combustion, transesterification, free fatty acid.

Effect of structural changes for pipe metal on damage of pipeline systems for oil product processing

Research has established that operational damage of pipeline systems for oil product processing (PSOP) occurs due to turbulent flow of the main product, caused by structural features, which leads to cavitation in a localized area under conditions favorable for development of cavitation-erosion embrittlement and failure. Continuous monitoring of the wall thickness of critical areas of branch pipes and reducers, and restoration of them with high quality materials makes it possible to exclude critical situations and improve their corrosion resistance. Unprotected iron and steel is subject to corrosion in the majority of media. The intensity of corrosion failure depends on a number of factors, the most important of which is the composition and condition of a metal surface, properties of the corrosive medium itself, and local conditions. Up to 40% of accidents in pipeline systems are connected with corrosion failure. Within the general production cycle for processing products, cases of corrosion failure are most often encountered for reducers in pipeline systems, and therefore a study was made of failed reducers for heat exchange equipment of pipeline systems for processing oil products in a unit for primary oil processing. Heat exchange equipment is intended for heat recovery from the output of overhead product of an atmospheric column (fraction NK-160°C, i.e., directly distilled benzene) with crude oil feedstock. Characteristics of the product entering the

Energy Return on Investment (EROI) of Oil Shale

The two methods of processing synthetic crude from organic marlstone in demonstration or small-scale commercial status in the U.S. are in situ extraction and surface retorting. The considerable uncertainty surrounding the technological characterization, resource characterization, and choice of the system boundary for oil shale operations indicate that oil shale is only a minor net energy producer if one includes internal energy (energy in the shale that is used during the process) as an energy cost. The energy return on investment (EROI) for either of these methods is roughly 1.5:1 for the final fuel product. The inclusions or omission of internal energy is a critical question. If only external energy (energy diverted from the economy to produce the fuel) is considered, EROI appears to be much higher. In comparison, fuels produced from conventional petroleum show overall EROI of approximately 4.5:1. “At the wellhead” EROI is approximately 2:1 for shale oil (again, considering internal energy) and 20:1 for petroleum. The low EROI for oil shale leads to a significant release of greenhouse gases. The large quantities of energy needed to process oil shale, combined with the thermochemistry of the retorting process, produce carbon dioxide and other greenhouse gas emissions. Oil shale unambiguously emits more greenhouse gases than conventional liquid fuels from crude oil feedstocks by a factor of 1.2 to 1.75. Much of the discussion regarding the EROI for oil shale should be regarded as preliminary or speculative due to the very small number of operating facilities that can be assessed.

Production of olefins via steam cracking of vegetable oils

Vegetable oils (in Europe particularly rapeseed) are the favoured raw material for production of methyl esters to be used as biodiesel. This paper discloses a possibility of their alternative utilization as crude oil substitute via vegetable oil steam cracking to produce short alkenes to be used in polyolefins production industry. During thermal decomposition under conditions matching those of gas-oil steam cracking (short residence time, temperature over 800 °C) vegetable oils form similar products as traditional crude-oil-based feedstocks. The yields of major pyrolysis products of various vegetable oils were determined using the apparatus employed previously to laboratory research of hydrocarbon pyrolysis and they were compared to yields obtained by cracking traditional feedstocks. Also the effects of hydrocarbon chain length and saturation of acyls forming the oils were analyzed in detail. The possibilities of processing vegetable oils by co-cracking in mixture with crude oil feedstocks are discussed and supported by experimental data.