Qatar Foundation Annual Research Forum Volume 2011 Issue 1

Fischer-Tropsch synthetic paraffinic kerosines (FT-SPKs), such as Gas-to- Liquids (GTL) Kerosine, are now accepted as suitable blend components for Jet fuel production, via ASTM D7566. This sets limitations on distillation profiles for the final fuel and neat SPK, and the cycloparaffin content of the neat SPK. SPKs, from FT and other production routes, can be envisaged that would fall outside these limits yet produce perfectly acceptable, even desirable fuels. They are not generally available yet but one can define their compositions in terms of key components (normal paraffins, iso-paraffins and cycloparaffins) and carbon number distributions, derived from 2-dimensional gas chromatography. Surrogate blends approximating to these compositions have been produced with existing FT kerosines and commercial solvents.

The methodology used to blend these surrogate fuels will be presented as well as the results of the first experimental campaign at Rolls-Royce Derby on 5 real and surrogate SPKs in Technology Readiness Level 3 (TRL 3) altitude relight tests, with a baseline crude-derived Jet A-1. SPK choices permitted the impact of several main compositional variables on laboratory and performance measures to be determined from the small fuel set. Standard specification tests and altitude relight tests were performed. Not only were engine/combustor performances assessed but also combustion processes were captured with high speed flame imaging subject to a poster by DLR (Mosbach et al). Laboratory tests showed some sensitivity to SPK composition (e.g. viscosity increasing and lower heating value decreasing with increased cycloparaffin content) but these were less evident with ignition relight test results. All SPKs ignited, suggesting that the distillation criteria could be relaxed from current values. There may be a positive impact of lower iso/normal content on ignition performance, but this needs testing in more advanced (higher TRL) equipment.

Increasing oil prices, strict environmental regulations and lack of sufficient growth in renewable energy sector have led to renewed interest in Fischer- Tropsch technology. Improved understanding of reaction mechanisms and development of detailed kinetic models for Fischer-Tropsch synthesis (FTS) would facilitate better design and optimization of all FTS reactor configurations.

In this work, detailed kinetic models have been developed utilizing mechanistic approach. Experiments were conducted over 25% Co/0.27%Ru/Al2O3 (in parts by weight) catalyst in a 1L stirred tank slurry reactor over a wide range of conditions. Langmuir-Hinshelwood-Hougen-Watson type rate expressions were derived for the entire product spectrum. Models are based on the assumption that 1-olefins re-adsorb on active sites. Effective pressure of olefin (PCnH2n*) at the catalyst surface was assumed to vary exponentially with carbon number (according to Henry's law).

The genetic algorithm followed by Levenberg-Marquardt method was used to estimate kinetic parameters for 13 models using a single set of process conditions (i.e. T = 220°C, P = 2.4 MPa, H2/CO feed ratio of 2.1, and gas space velocity of 6 NL/g-cat/h). Two models FT-6 and FT-8 showed carbon number dependent chain growth probability and olefin to paraffin ratios. The model predictions were in good agreement with experimental data. Model FT-6 is based on dissociative adsorption of CO, followed by Eley-Rideal reaction with molecular H2, while FT-8 follows dissociative adsorption of CO and H2, to form building block monomer CH2. For both of the models, chain growth takes place by alkyl mechanism and oE-olefins are formed by aB-hydride elimination reaction. Formation of paraffin occurs via single-site reaction with molecular hydrogen (FT-6) or via dual site reaction with adsorbed hydrogen (FT-8).

Parameter estimation resulted in at least one negative parameter in both models. However, to assess the physical meaningfulness of results and the true values of kinetic parameters, one has to use data at multiple sets of process conditions. This work is in progress. Nevertheless, from a qualitative point of view initial results provide valuable insight into selection of reaction mechanisms and rate determining steps for future developments and refinements.

Plastics, which are basically polymer materials, are now an integral part of our daily lives: packaging, transport, textile, Hi-technology… Total Petrochemicals produces and develops useful lightweight and durable plastics that play a key role in the sustainable development of our world, making our lives easier, cleaner, safer and more enjoyable. These products include polyethylene, polypropylene, polystyrene but also since recently polylactic acid, a biopolymer based on a renewable raw material.

Plastics are produced by polymerizing monomer units (ethylene in the case of polyethylene) under certain temperature and pressure conditions and most of the time in the presence of a catalyst. Catalysts, and more particularly organometallic species, are the cornerstones of the production of these polymers. Since 1980, the polyolefin field has undergone a revolution with the development of single-site catalysts referred to as metallocenes. The metallocene catalyst technology helps produce polyolefins, which boast improved chemical and physical properties and are less heavy and less bulky than those traditionally produced.

Total Research Center-Qatar (TRC-Q) researchers, jointly with Total Petrochemicals Research and Development teams, prospect and develop new catalysts to design and manufacture innovative high-level performance plastics. The objective is to optimize the catalysts synthesis for industrial scale application and to produce such catalysts in high yields in the most efficient way.

There is a direct relation between the catalyst structure and the polymer chemical and physical properties. The relation is investigated by changing the size and type of the catalyst substituents; metallic centers … (steric, electronic and symmetrical modifications of the catalysts); and studying the impact of such changes on the polymer microstructure.

A set of products has been selected to explain this relation and bring to light new advances in polyolefins and biopolymers catalysis.

Membrane distillation differs from other membrane technologies in that the driving force for desalination is the difference in vapor pressure of water across the membrane, rather than total pressure. The membranes for MD are hydrophobic, which allows water vapor (but not liquid water) to pass. The vapor pressure gradient is created by heating the source water thereby elevating its vapor pressure. The major energy requirement is for low-grade thermal energy. Moreover, the Qatari economy is based on its massive hydrocarbon industry. In such industries water is routinely used in a number of applications in the form of process or cooling water. In a number of cases the water used can be seawater but with certain restrictions due to corrosion, fouling and water composition, large volumes of fresh water are required around the chemical plants. It is well known that many processes produce large amounts of excess heat i.e., heat beyond what can be efficiently used in the process. Industrial waste heat recovery methods attempt to extract some of the energy as work that otherwise would be wasted. Typical methods of recovering heat in industrial applications include direct heat recovery to the process itself, economizers, regenerators, and waste heat boilers.

An investigation into the potential of using industrial low-grade waste heat in desalination using membrane distillation has been carried out. Three well-known chemical processes were considered: LNG, ethylene and VCM. Using an approach based on pinch technology for heat integration, process streams in the three processes were screened to eliminate unsuitable sources of low-grade heat. Consequently, the LNG and ethylene processes were eliminated because of their unsuitable cooling curves that tended to highlight extreme temperatures. The VCM process on the other hand showed a promising outlook, in particular in the direct chlorination section where a major vapor stream is condensed through the temperature range 118 to 460C. This is precisely the ideal range for low -grade heat recovery. Exploiting literature data and modeling concepts, a flowsheet for a potential MD plant was designed with relevant terminal temperatures.

In the recent years, development of alternative jet fuels is gaining importance owing to the demand for diversifying fuel and cleaner combustion. Liquid fuels have high volumetric energy content and ease of handling therefore preferred by the aviation industry. However, liquid fuels add additional complications in combustion process in thrust generation due to the needed preparatory steps of atomization and vaporization. Alternate jet fuels then must meet the vital needed requirements such as rapid atomization, vaporization, quick re-ignition at high altitude, stable combustion before being used.

At TAMUQ - Micro-Scale Thermo Fluids Laboratory (MSTF), an experimental facility is designed and developed to carry out a detailed investigation on the spray characteristics of jet fuels at different injection conditions. The spray characteristics such as droplet size, velocity and spray cone angle are investigated at different injection pressures. These details are obtained using the state-of-the-art non-intrusive laser diagnostics techniques. Experimental techniques involving both point-wise as well as plane-wise measurements are planned using the Phase Doppler Particle Analyzer (PDPA) and Global Sizing Velocimetry (GSV) respectively to obtain the spray characteristics.

Initially, water is used to tune and establish experimental parameters in TAMUQ spray characterization facility followed by the conventional jet fuel, JetA1. The spray characteristics of water will then be compared with that of JetA1 fuel. This facility will later be used to study the spray characteristics of different gas-to-liquid (GTL) fuels as part of the on-going Qatar Science and Technology Park (QSTP) funded project involving Texas A&M at Qatar (TAMUQ), German Aerospace Laboratory (DLR), and Rolls-Royce (UK). The main objective of this work is to support the initial phase of the QSTP funded project. The spray characterization facility developed at TAMUQ will help to explore the potential of GTL fuels as an environmental friendly, alternate jet fuel.

Cobalt (Co) turnover frequency (TOF) has been reported to be independent of Co dispersion and support type. However, wide discrepancies in Co TOF values exist in the literature. Differences in catalyst preparation, process conditions, and characterization technique could be major factors that may account for the discrepancies. Therefore, a more accurate assessment of Co turnover frequency (TOF) is needed. In this study, Co TOFs over different Co/Al2O3 catalysts promoted with Pd, Ru, Pt and Re at the beginning of reaction and at steady state were determined. The catalysts were prepared in different batches, which resulted in two Co cluster sizes: small Co particle size (∼6 nm) and large Co particle size (11.5 nm). Fischer-Tropsch synthesis (FTS) reaction was carried out at different conditions in a continuous stirred tank reactor (CSTR). All promoted Co catalysts were characterized using BET, TPR, H2-chemisorption and pulse re-oxidation. The FTS was conducted at 220–230 °C, 1.5 MPa, 6–13 Nl/gcat/h and H2/CO = 2.1. Results indicate that catalyst preparation including promoter effect and process conditions significantly impact initial and steady state TOF values. The Co catalysts with larger particles had a larger Co TOF and low space velocity (SV) reduced the number of Co active sites due to severe catalyst deactivation at high CO conversion. For SV of 8.0–13.0 Nl/g-cat/h and 1.5 MPa, high Co TOF values (0.074–0.082 s⁻1, at 210 °C) over the Re and Pt promoted 25%Co/Al2O3 were achieved and were in good agreement with recently published value (0.073s⁻1) in a few literature. Moreover, these values are about two times the values (0.023–0.045 s⁻1) reported in some Co related literature under similar conditions. Therefore, true TOF on single Co cluster with the size of 11.5 nm at 210 °C and 1.5–2.0 MPa should be about 0.073–0.082 s⁻1 (this value is conversion dependent). The effect of promoters (Pd, Ru, Pt and Re) and process conditions on FTS activity and selectivities (hydrocarbons, watersoluble oxygenates and CO2) was also studied.

The current technology for CO2 reduction is CO2 capture and storage (CCS). An alternative technology is to capture CO2 and convert it to chemicals by thermal catalysis. The technology is not appropriate to low concentration of CO2 (<1%), such as CO2 in air except it has to be driven by thermal energy mainly produced by fossil fuel combustion. The solar energy driven CO2 conversion is an only technology without extra CO2 emission (neutral carbon process) and very compatible with atmospheric CO2 condition. Solar energy is most abundant in the world. However, it is difficult to store the produced electric energy in large quantities using the present technologies. Hereby there is still a real need to exploit other methods to easily convert and store solar energy alongside discovering new technologies to largely store electric energy. Photocatalysis, utilizing solar energy to drive chemical reactions over a photocatalyst, is a novel and advanced technology. Solar hydrogen production is an approach to convert solar energy to chemical energy hydrogen by means of photocatalysis. Alternatively, the photoreduction of CO2 directly to a renewable fuel, such as methanol is another approach to convert and store solar energy in chemical bonds. Compared with hydrogen, methanol is a superior fuel due to 1) its higher energy density (1000 times higher than hydrogen per volume) and 2) easier storage and transporation.

Photocatalytic CO2 conversion towards methanol mimics natural plant photosynthesis. Nature represents the blueprint for storing sunlight in the form of chemical fuels (such as sugars) by CO2 conversion. The primary steps of natural photosynthesis involve the absorption of sunlight and its conversion into separated electron/hole pairs. The holes of this wireless current are then captured by the oxygen-evolving complex (OEC) to oxidize water to oxygen, which allows the electrons are captured by PSI to reduce NADP+ to NADPH (the reduced form of NADP+).

In this paper we will offer an overview of this emerging technology and its potential applications by using cheap inorganic photocatalyst instead of complex proteins/enzymes while the reduction product is methanol rather than NADPH.

Qatar has high increasing electrical energy demand, from less than 50MW 1954 to 5,250MW in 2010. Electrical energy generating was only 1,500MW in 1995, 4,535MW in 2009, and soon will be 9,000MW. The expected additional capacity needed by 2016 is 5,500MW with high average emission CO2 of 32 tons/capita/year.

Qatar has strong solar energy potential, (2070–2250)kWH/m2yr, which could takes place to fulfill the future need energy balance towards Qatar Vision 2030. The mean hourly, daily, monthly and yearly solar irradiation data measured on ground and by satellite collected for several cities such as: Doha, Dukhan, Al-Khor, Ruwais, Abu-Samra, Al-Utoriyah, and Rodhat Al-Faras have been investigated. The measured data on ground is compared with the satellite's data. This preliminary investigation and data analysis could be good preliminary design for “Qatar Solar Atlas”.

The electrical energy consumption breakdown by sectors: residential, commercial, government, industrial, and the total consumption through (2007–2009) are studied. The residential sector is the highest consumption 35 % while the industrial sector uses less. Residential villa consumes three times residential flat. This sector needs energy auditing to save energy in A/C and lighting energy.

The objective of this research is to assist and lead the authority and government to the energy roadmap, energy footprint, Qatar solar atlas, and energy policy to secure energy future with minimizing energy demand and presenting the solar energy potential.

In this research the energy demand and energy forecasting for the nearest future to achieve Qatar Vision 2030 are presented. The energy required to be installed is addressed with emphasize on the solar energy potential with gradually application using mature and proven solar technology. Several scenarios to present Qatar forecasting electrical power demand to 2024 as base case, low and high expected values is presented. The peak expected load through 2022 world football club is considered.

The world is running out of energy, thus energy preservation is of paramount importance. Using current technology, ethylene is purified from petroleum feed stocks using the very energy intensive cryogenic distillation method. However, a purification procedure based on the redox properties of nickel bis-dithiolene complexes has been theoretically studied, in order to design a more convenient route to ethylene purification. Several possible addition routes of ethylene to neutral and anionic Ni(S2C2(CN)2)2 complexes have been modeled using density functional theory. An intraligand addition and subsequent decomposition is preferred for the neutral complex, while the interligand adduct is formed in the presence of the anion, in line with previous experimental results. The effect of the anion, whose role is as a mediator in the initial step of the reaction, is discussed, and the ability of this compound to avoid poisoning by acetylene is investigated. The results from the CN substituted complex are then compared with that of ethylene addition to CF3, H, and OH substituted nickel dithiolene complexes.

Miniaturization and increase in performance of electronic devices, resulted in an increase of energy density loads generated. In recent times, micro-scale cooling devices such as microchannel heat sinks have evolved as a plausible solution to the above heat transfer challenge. Nanofluids emerged as a good candidate in improving the cooling performance of micro cooling systems. Nanofluids are colloidal suspensions consisting of nano-sized particles (less than 100nm) dispersed in a base fluid. Nanofluids are considered ideal for micro-channel devices because they not only improve the heat transfer capabilities, due to increased thermal conductivity, but also minimize the clogging problem. Present work experimentally investigates the heat transfer performance of nanofluids through a microchannel with constant temperature wall boundary condition. Laminar flow of SiO2-water nanofluids inside a rectangular microchannel flow assembly is examined. The effect of flow rate on thermal performance of nanofluid is analyzed along with variation in thermo-physical properties. Interestingly, experimental results shows heat transfer enhancement at lower flow rates and heat transfer degradation at higher flow rates. Theoretical reasoning for this kind of opposing trend is given based on flow conditions and thermo-physical properties of nanofluids. Moreover, Novel near surface velocity measurement of Nanofluids compared with that of regular fluid at the same condition.