Kinetic model construction using chemoinformatics

Kinetic models of chemical processes not only provide an alternative to costly experiments; they also have the potential to accelerate the pace of innovation in developing new chemical processes or in improving existing ones. Kinetic models are most powerful when they reflect the underlying chemistry by incorporating elementary pathways between individual molecules. The downside of this high level of detail is that the complexity and size of the models also steadily increase, such that the models eventually become too difficult to be manually constructed. Instead, computers are programmed to automate the construction of these models, and make use of graph theory to translate chemical entities such as molecules and reactions into computer-understandable representations. This work studies the use of automated methods to construct kinetic models. More particularly, the need to account for the three-dimensional arrangement of atoms in molecules and reactions of kinetic models is investigated and illustrated by two case studies. First of all, the thermal rearrangement of two monoterpenoids, cis- and trans-2-pinanol, is studied. A kinetic model that accounts for the differences in reactivity and selectivity of both pinanol diastereomers is proposed. Secondly, a kinetic model for the pyrolysis of the fuel “JP-10” is constructed and highlights the use of state-of-the-art techniques for the automated estimation of thermochemistry of polycyclic molecules. A new code is developed for the automated construction of kinetic models and takes advantage of the advances made in the field of chemo-informatics to tackle fundamental issues of previous approaches. Novel algorithms are developed for three important aspects of automated construction of kinetic models: the estimation of symmetry of molecules and reactions, the incorporation of stereochemistry in kinetic models, and the estimation of thermochemical and kinetic data using scalable structure-property methods. Finally, the application of the code is illustrated by the automated construction of a kinetic model for alkylsulfide pyrolysis

Syntrophy drives the microbial electrochemical oxidation of toluene in a continuous-flow "bioelectric well"

Microbial electrochemical technologies (MET) are promising for the remediation of groundwater pollutants such as petroleum hydrocarbons (PH). Indeed, MET can provide virtually inexhaustible electron donors or acceptors directly in the subsurface environment. However, the degradation mechanisms linking contaminants removal to electric current flow are still largely unknown, hindering the development of robust design criteria. Here, we analysed the degradation of toluene, a model PH, in a bioelectrochemical reactor known as "bioelectric well"operated in continuous-flow mode at various influent toluene concentrations. With increasing concentration of toluene, the removal rate increased while the current tended to a plateau, hence the columbic efficiency decreased. Operation at open circuit confirmed that the bioelectrochemical degradation of toluene proceeded via a syntrophic pathway involving cooperation between different microbial populations. First of all, hydrocarbon degraders quickly converted toluene into metabolic intermediates probably by breaking the aromatic ring upon fumarate addition. Subsequently, fermentative bacteria converted these intermediates into volatile fatty acids (VFA) and likely also H2, which were then used as substrates by electroactive microorganisms forming the anodic biofilm. As toluene degradation is faster than subsequent conversion steps, the increase in intermediate concentration could not result in a current increase. This work provides valuable insights on the syntrophic degradation of BTEX, which are essential for the application of microbial electrochemical system to groundwater remediation of petroleum hydrocarbons

NASA SBIR abstracts of 1991 phase 1 projects

The objectives of 301 projects placed under contract by the Small Business Innovation Research (SBIR) program of the National Aeronautics and Space Administration (NASA) are described. These projects were selected competitively from among proposals submitted to NASA in response to the 1991 SBIR Program Solicitation. The basic document consists of edited, non-proprietary abstracts of the winning proposals submitted by small businesses. The abstracts are presented under the 15 technical topics within which Phase 1 proposals were solicited. Each project was assigned a sequential identifying number from 001 to 301, in order of its appearance in the body of the report. Appendixes to provide additional information about the SBIR program and permit cross-reference of the 1991 Phase 1 projects by company name, location by state, principal investigator, NASA Field Center responsible for management of each project, and NASA contract number are included

An a priori thermodynamic data analysis based chemical lumping method for the reduction of large and multi-component chemical kinetic mechanisms

A chemical species lumping approach for reduction of large hydrocarbons and oxygenated fuels is presented. The methodology is based on an a priori analysis of the Gibbs free energy of the isomer species which is then used as main criteria for the evaluation of lumped group. Isomers with similar Gibbs free energy are lumped assuming they present equal concentrations when applied to standard reactor conditions. Unlike several lumping approaches found in literature, no calculation results from the primary mechanism have been employed prior to the application of our chemical lumping strategy. An 807 species and 7807 individual reactions detailed mechanism comprising n-decane, alpha-methylnaphthalene and methyl decanoate has been used. The thermodynamic data have been analyzed and 74 isomer groups have been identified within the oxidation of n-decane and methyl decanoate. The mechanism reduction has led to a mechanism size of 463 species and 7600 reactions. Thereafter the lumped mechanism has been checked under several reactor conditions and over a broad range of temperature, pressure, and equivalence ratio in order to quantify the accuracy of the proposed approach. In all cases, very good agreement between the predictions obtained using the lumped and the detailed mechanism has been observed with an overall absolute error below 12%. Effects of the lumping procedure on sensitivities and on isomer concentrations were considered to further demonstrate the validity of the proposed approach

Metagenomics-driven predictions in Archaea from hydrocarbon-rich Arctic hydrothermal systems: Phylogenetic and metabolic analyses of methane and short-chain alkane-degrading lineages

Postponed access: the file will be accessible after 2023-10-14Metan og hydrokarboner er potente klimagasser som produseres og nedbrytes hovedsakelig biotisk. I havet akkumuleres metan og hydrokarboner i sedimenter og hydrotermiske systemer. Nylige metagenomstudier har utvidet mangfoldet av slektslinjer av arker involvert i metan- og hydrokarbonsyklus. De har vist at metabolske moduler for omsetningsreaksjoner i hydrokarbonsyklus er vanlige i arker og kan forekomme i heterotrofe slektslinjer som bestemmer en mixotrofisk livsstil. Ytterligere metagenomstudier kan bidra til å øke forståelsen av den miljømessige rollen mikroorganismer involvert i omsetning av hydrokarboner har. I løpet av det siste tiåret har hydrokarbon-anrikede hydrotermiske systemer blitt oppdaget langs de arktiske midthavsryggene. I dette studiet har fokuset vært å beskrive det fylogenetiske og metabolske mangfoldet av anaerobe hydrokarbonnedbrytende slektslinjer i disse systemene, hovedsakelig ved å analysere genomer rekonstruert fra metagenomdata. Flere nye slektslinjer av anaerobe metanotrofe arker av typen ANME-1, ble identifisert, inkludert en ny familie. To slektslinjer som kunne oksidere kortkjedede hydrokarboner, henholdsvis etan og propan/butan ble også identifisert. Samtlige av slektslinjene benyttet etablerte metabolismeveier for syntrof anaerob oksidasjon av metan og hydrokarboner. Tidligere ubeskrevne funksjonelle forskjeller ble imidlertid identifisert mellom ulike ANME-1. Basert på tidligere funn i terrestriske hydrotermiske systemer, ble potensialet for metanoksidasjon også evaluert i rekonstruerte genomer av Korarchaeia. Korarchaeia fra marine hydrotermiske system, ble funnet å mangle gen for anaerob oksidasjon av metan. De ble i stedet identifisert som fermenterende mikroorganismer med evne til å benytte sukker og aminosyrer. En komplett Wood-Ljungdahl metabolismevei ble identifisert i dypforgrenede slektslinjer av Korarchaeia og gir sannsynligvis grunnlag for homoacetogenese. Totalt sett har denne studien bekreftet at hydrokarbonrike hydrotermiske systemer ved de arktiske midthavsryggene er tilholdssted for slektslinjer med potensial for hydrokarbonnedbrytning og bidrar til å utvide det fylogenetiske og funksjonelle mangfoldet av slektslinjer som bryter ned hydrokarboner i marine hydrotermiske systemer.Methane and short chain alkanes are potent greenhouse gases generated and degraded mainly biotically. In the ocean, methane and hydrocarbons accumulate in sediments and hydrothermal vents. Recent metagenomic studies have dramatically expanded the diversity of archaeal lineages involved in methane and hydrocarbon cycling. They also have revealed that metabolic modules at the basis of hydrocarbon cycling are relatively conserved and common in Archaea and can occur in heterotrophic lineages determining a mixotrophic lifestyle. Further metagenomic studies can contribute to expand such diversity and describe the environmental role of microorganisms involved in cycling of hydrocarbons. In the last decade, hydrocarbon-enriched hydrothermal vents have been discovered along the Arctic Mid Ocean Ridges (AMOR). This project aimed at identifying lineages of anaerobic hydrocarbon-degraders in these vents and describe their phylogenetic and metabolic diversity, mainly by reconstructing and analyzing metagenome-assembled genomes (MAGs) from various anoxic and actively venting hydrothermal locations. Potential for methane oxidation was also evaluated in MAGs of Korarchaeia since they have been previously proposed as methane oxidizers in terrestrial environments. Overall, several new lineages of anaerobic methanotrophic archaea ANME-1 were identified, including one new family. Two lineages of short-chain alkane oxidizers were found, one an ethane oxidizer and the other a butane/propane oxidizer. All encoded canonical routes for syntrophic anaerobic oxidation of methane and short-chain alkanes. Previously undescribed functional differences were found between ANME-1 lineages. Marine hydrothermal Korarchaeia did not encode genes for anaerobic oxidation of methane. They were instead identified as sugars and amino acids fermenters. Deep-branching lineages of Korarchaeia encoded a complete Wood-Ljungdahl pathway that is likely used reductively as electron sink during fermentation resulting in a homoacetogenic metabolism. Overall, this study confirms that hydrocarbon-rich hydrothermal vents at AMOR host microbial lineages with the potential for degradation of hydrocarbons and contributes to expanding the known phylogenetic and functional diversity of hydrocarbon-degrading lineages in marine hydrothermal systems.Doktorgradsavhandlin

Genetic relation of C02 and its suitable usage in the Peninsular Malay Basin.

Reservoirs with high C02 content are connnon throughout the Asia Pacific region, notably the Gulf of Thailand, Malaysia, Indonesia and Vietnam. In Malay Basin, C02 production ranges from 5 to 90% mol. The high production of C02 is concentrated in certain region in the Malay Basin. The most notable high production of C02 is the northern region near Thailand and the center of Malay Basin. The comprehensive study on C02 genetic relation and its source haven't been established yet. For this project the authors have studied the origin of produced C02 in order predicts the continuous supply for field development program. The author also made a comprehensive study on the tectonic framework, stratigraphy, various plays and geothermal gradient of Malay Basin to relate with the existence of associated gas. For the development program EOR operation is preferable among others since it is the suitable due to numerous of C02 supply from the field. The C02 flooding operation will be discussed in this report where the details modeling for reservoir and well are established to predict the performance of the reservoir with C02 flooding. Results from the modeling indicate C02 flooding as EOR may be suitable for further development plan to increase the production of oil up to 20 % from naturally flow well. In the fmal chapter of this report, the author relates the statigraphy, heat flow and plays in Malay Basin to conclude the finding on origin of C02 in Malay Basin. The high production of C02 is mainly originated from inorganic origin while low production of C02is from organic origin; The isotopic value of o 13C is used to distinguish between these two types of C02

Development of an ontology supporting failure analysis of surface safety valves used in Oil & Gas applications

Treball desenvolupat dins el marc del programa 'European Project Semester'.The project describes how to apply Root Cause Analysis (RCA) in the form of a Failure Mode Effect and Criticality Analysis (FMECA) on hydraulically actuated Surface Safety Valves (SSVs) of Xmas trees in oil and gas applications, in order to be able to predict the occurrence of failures and implement preventive measures such as Condition and Performance Monitoring (CPM) to improve the life-span of a valve and decrease maintenance downtime. In the oil and gas industry, valves account for 52% of failures in the system. If these failures happen unexpectedly it can cause a lot of problems. Downtime of the oil well quickly becomes an expensive problem, unscheduled maintenance takes a lot of extra time and the lead-time for replacement parts can be up to 6 months. This is why being able to predict these failures beforehand is something that can bring a lot of benefits to a company. To determine the best course of action to take in order to be able to predict failures, a FMECA report is created. This is an analysis where all possible failures of all components are catalogued and given a Risk Priority Number (RPN), which has three variables: severity, detectability and occurrence. Each of these is given a rating between 0 and 10 and then the variables are multiplied with each other, resulting in the RPN. The components with an RPN above an acceptable risk level are then further investigated to see how to be able to detect them beforehand and how to mitigate the risk that they pose. Applying FMECA to the SSV mean breaking the system down into its components and determining the function, dependency and possible failures. To this end, the SSV is broken up into three sub-systems: the valve, the actuator and the hydraulic system. The hydraulic system is the sub-system of the SSV responsible for containing, transporting and pressurizing of the hydraulic fluid and in turn, the actuator. It also contains all the safety features, such as pressure pilots, and a trip system in case a problem is detected in the oil line. The actuator is, as the name implies, the sub-system which opens and closes the valve. It is made up of a number of parts such as a cylinder, a piston and a spring. These parts are interconnected in a number of ways to allow the actuator to successfully perform its function. The valve is the actual part of the system which interacts with the oil line by opening and closing. Like the actuator, this sub-system is broken down into a number of parts which work together to perform its function. After breaking down and defining each subsystem on a functional level, a model was created using a functional block diagram. Each component also allows for the defining of dependencies and interactions between the different components and a failure diagram for each component. This model integrates the three sub-systems back into one, creating a complete picture of the entire system which can then be used to determine the effects of different failures in components to the rest of the system. With this model completed we created a comprehensive FMECA report and test the different possible CPM solutions to mitigate the largest risks

Rotary kiln incineration of hazardous wastes: pilot-scale studies at Louisiana State University

Studies of incineration of surrogates for hazardous wastes are conducted in the pilot-scale rotary kiln incinerator (RKI) at Louisiana State University (LSU) in Baton Rouge, Louisiana. The purpose of the research is to investigate methods of treating and destroying hazardous wastes in a cost-effective and environmentally sound way. The objective is to provide process data that will contribute to increased knowledge for RKI design and operation. The LSU facility is a College of Engineering Combustion Laboratory that is unique in its large size as a university laboratory. It is equipped with individual instruments for analysis of O2, CO, CO2, HCl, SOx and NOx and a mass spectrometer to continuously monitor products of combustion for rigorous evaluation of efficiencies of operation. Experiments conducted to investigate parameters and variables affecting the design and operation of the kiln substantiate mathematical treatment of material and energy balances. These investigations add new and useful data to be used in design of rotary kilns, a major objective of this research. One of the principal contributions of this dissertation relates to the effects of batch feeding on instability of the combustion process. Surges in temperature, pressure, and their effects on products of incomplete combustion are discussed. Other activities of the combustion laboratory are described: Incineration of still bottoms to recover byproduct potash produced by the Audubon Sugar Institute; burning of synthetic fireplace logs; study of incinerator stack gases; and determination of rates of fugitive emissions from flanges and valves. Economics of operation and maintenance of the facility are calculated, tabulated, and related to contract charges for combustion studies on behalf of industrial clients. Future prospects for the laboratory as a research and teaching facility are discussed

Marine Biotechnologies for the Decontamination and Restoration of Degraded Marine Habitats

This research presents the results obtained using a bioremediation approach aiming to enhance natural remediation of the Bagnoli-Coroglio area, a post industrial site in the Gulf of Naples, Italy, characterized by the presence of several pollutants released in almost a century by the ILVA steel plant. In particular, the thesis evaluates the benthic microbial taxonomic composition of this area after ten decades of pollution. Results indicate the prevalence of the Phyla Proteobacteria, (36.7%), Planctomycetes (20.5%) and Bacteroidetes (9.6%) and the presence of a core microbiome suggesting that pollutants and other abiotic factors may have contributed to shape benthic prokaryotic communities. The thesis also evaluates the biotechnological potential of single isolates bacteria (Halomonas sp., Alcanivorax sp., Epibacterium sp., Pseudoalteromonas sp., and Virgibacillus sp.) and mixtures of these species isolated from polluted sediments collected from Bagnoli-Coroglio area and the Sarno river mouth, another polluted site in the Gulf of Naples. Laboratory tests highlighted the ability of mixed cultures and single taxa to degrade PAHs (Polyclic Aromatic Hydrocarbons) and precipitate heavy metals from culture media. Results of Sequential Selective Extraction (SSE) analysis emphasized the ability of mixed cultures to reduce the mobility of As, Cd and Zn by changing their partitioning in the geochemical fractions. Full genome sequencing of isolated strains has allowed for the genetic and molecular characterization of mechanisms underlying processes of degradation and detoxification of xenobiotics. In particular, many genes involved in hydrocarbon degradation pathways and in heavy metal detoxification systems have been identified. My results suggest a potential biotechnological application of these strains in waste-water treatment as well as decontamination of polluted sediments

Fretting corrosion of tin-plated separable connectors used in automotive applications

Greater demands are being placed on the separable connector to perform with higher reliability in harsher automotive environments. Corrosion in its various forms is a major mechanism which affects contact reliability and this current work focuses on surface oxidation and the related phenomenon of fretting corrosion, from which hot dipped tin (HDT), a common automotive connector coating, is known to suffer. For an in-depth study of high contact resistance, in both static conditions and when subjected to relative micromovement, an interdisciplinary approach was necessary, drawing on the results of published work carried out in the fields of contact and surface science, corrosion and tribology. [Continues.