Synthetic Liquid Fuels Research Articles

Анализ конкурентных преимуществ производства синтетических жидких топлив: мировой опыт и отечественная практика

Анализ конкурентных преимуществ производства синтетических жидких топлив: мировой опыт и отечественная практика

Methane conversion in a mixture of enriched air and water vapor

On the basis of thermodynamic analysis of the methane partial oxidation (conversion) process in a mixture of enriched air and water vapor, the conditions of practical implementation of such a process are determined for the integrated energotechnological use of natural gas with coproduction of electricity and synthetic liquid fuels. Considerable attention is paid to the conditions of formation of solid carbon (carbon black) in partial oxidation, and the means to reduce its yield are discussed.

ChemInform Abstract: Fischer—Tropsch Reaction on a Thermally Conductive and Reusable Silicon Carbide Support

AbstractReview: 199 refs

The Need for Public-Private Partnership Model in the South African Coal-Mining Industry

Coal is a strategic commodity in South Africa as it is the Primary source of energy in form of electricity and synthetic liquid-fuels. It is also a feedstock in the heavy industries that include steel, cement, aluminium smelters and paper. Its role in socio-economic development spans over 100 years. Therefore, the importance of coal supply chain cannot be overemphasised. The mining industry and the role players comprises the South African government, public and private enterprises. Hence, there is need for collaboration of the three parties in a public-private partnership (PPP) model to enhance operational effectiveness and efficiency.The government role in the legislative environment, issuing of exploration, mining and water licenses among others is crucial for the industry. The state-owned corporations such as Transnet, the only national rail transport logistics company and electricity supply company (Eskom), the main electricity generating company and the leading customer/consumer of the South African coal underpins the extent of the state involvement in the industry. The private sector role of ownership of the coal-mines is dominated by the big five international organisations namely BHP Billiton, Anglo Coal, Xstrata/Glencore, Sasol and Exxaro and the black economic empowerment (BEE) companies or junior miners. The electricity and the liquid-fuels types of energy impact on all sectors of the economy. It is this complex relationship by all the role players in the coal-mining industry supply chain that requires enhanced collaboration in a PPP model to harmonise the entire operations in the value-chain. The relationship of the industry players was observed through the mining process, coal transportation to the domestic customers/consumers and export markets. The coal transport logistics infrastructures comprising conveyor belts, rail, road and water were explored and constraints requiring PPP solutions identified. DOI: 10.5901/mjss.2014.v5n4p224

Fischer–Tropsch Reaction on a Thermally Conductive and Reusable Silicon Carbide Support

The Fischer-Tropsch (FT) process, in which synthesis gas (syngas) derived from coal, natural gas, and biomass is converted into synthetic liquid fuels and chemicals, is a strongly exothermic reaction, and thus, a large amount of heat is generated during the reaction that could severely modify the overall selectivity of the process. In this Review, we report the advantages that can be offered by different thermally conductive supports, that is, carbon nanomaterials and silicon carbide, pure or doped with different promoters, for the development of more active and selective FT catalysts. This Review follows a discussion regarding the clear trend in the advantages and drawbacks of these systems in terms of energy efficiency and catalytic performance for this most-demanded catalytic process. It is demonstrated that the use of a support with an appropriate pore size and thermal conductivity is an effective strategy to tune and improve the activity of the catalyst and to improve product selectivity in the FT process. The active phase and the recovery of the support, which also represents a main concern in terms of the large amount of FT catalyst used and the cost of the active cobalt phase, is also discussed within the framework of this Review. It is expected that a thermally conductive support such as β-SiC will not only improve the development of the FT process, but that it will also be part of a new support for different catalytic processes for which high catalytic performance and selectivity are strongly needed.

Synthetic Liquid Fuels Obtained by Thermolysis of Animal Waste

Modern methods of recycling organic waste are not considered viable today. Therefore, an important advantage of the proposed technology is to obtain mineral fuel products as an output. The technologies of high-temperature processing are based on thermal decomposition of waste without oxygen at high temperature. In pyrolysis, wastes are converted into gaseous, liquid and solid fuels. Thereby, the properties and composition of the liquid feedstock obtained by pyrolysis with a boiling temperature in the range of X.I. (38) - 180°C, 180 - 320°C and more than 320°C were investigated. Residue with a boiling temperature over 320° C (52.4% vol.) is the main portion of the synthetic liquid fuels (SLF). It can be attributed to fuel oil grade 100 and used as boiler fuel or fuel oil additives according to the studied physicochemical parameters.

A review of advanced catalyst development for Fischer–Tropsch synthesis of hydrocarbons from biomass derived syn-gas

Fischer–Tropsch synthesis (FTS) is a process which converts syn-gas (H2 and CO) to synthetic liquid fuels and valuable chemicals. Thermal gasification of biomass represents a convenient route to produce syn-gas from intractable materials particularly those derived from waste that are not cost effective to process for use in biocatalytic or other milder catalytic processes. The development of novel catalysts with high activity and selectivity is desirable as it leads to improved quality and value of FTS products. This review paper summarises recent developments in FT-catalyst design with regards to optimising catalyst activity and selectivity towards synthetic fuels.

Recent Developments in the Partial Oxidation of Methane to Syngas

Natural gas is catalytically converted into several bulk chemicals such as ammonia, methanol, dimethyl ether, and synthetic liquid fuels by Fischer-Tropsch synthesis and similar processes. The main step in the conversion of natural gas to these products is the production of synthesis gas with the desired composition ranging from H2/CO = 3:1 used for the production of ammonia to the 1:1 mixture preferred for production of dimethyl ether. Catalysts and catalytic processes are important in the production of synthesis gas from natural gas. In this work, relevant catalytic systems employed recently in the production of syngas by the catalytic partial oxidation of methane, as well as experimental evidences on the reaction mechanisms are examined. Differences in methane dissociation, binding site preferences, stability of OH surface species, surface residence times of active species and contributions from lattice oxygen atoms and support species are considered. The methane dissociation requires reduced metal sites, but at elevated temperatures oxides of active species may be reduced by direct interaction with methane or from the reaction with H2 and CO (or C). The comparison of elementary reaction steps on Pt and Rh illustrates the fact that a key factor to produce hydrogen as primary product is a high activation energy barrier to the formation of OH. Another essential property for the formation of H2 and CO as primary products is a low surface coverage of intermediates, such that the probability of O-H, OH-H and CO-O interactions is reduced.

Technical Feasibility of Small-Scale GTL Process towards Heat Integration: A Case Study of Nongtum A Reservoir in Thailand

Natural gas can be a raw material to produce synthetic liquid fuels via Gas to Liquid process (GTL). The process is consist of 4 main parts which are cleaning unit, reforming unit, Fischer-Tropsch unit (FT) and product upgrading unit. To evaluate potential of having this kind of process for Nongtum A Reservoir, Thailand, technical feasibility of GTL process towards heat integration needed to be done. This work presented a process model, combined heat and power (gas generation) of Nongtum A Reservoir by using the total heat integration concept. Volume of natural gas at Nongtum A Reservoir is 56,634 m3/day at 10 bar, and 40 deg.C. ResuIts of the model simulation are the overall thermal efficiency of 10.32% to 14.88%, gasoline product of 435 to 575 bbl/day, and diesel product of 621 to 947 bbl/day depending upon a split ratio of natural gas to gas generation.

Possible transport energy sources for the future

In the medium to long term, low fossil fuel availability will make it necessary to find alternatives. Mass production of biofuels will not be a practical solution because it requires strong competition for land that is used for growing food. Therefore, it will be necessary to revise the frame of transportation energy sources. The number of pure light- and heavy-duty electric vehicles could increase in urban areas. Instead, it will be hard to find a viable alternative to the internal combustion engine for extra-urban transport vehicles, therefore alternative synthetic fuels could be used to compensate for fossil fuel depletion. Aside from a small share obtainable from biomass, most synthetic fuels are expected to be obtained from coal. Among these, synthetic natural gas represents a very good solution. In fact, synthetic natural gas will be advantageous with respect to hydrogen, whose on-board storage will be an unsolved problem in the medium term, and with respect to synthetic liquid fuels, which require more energy in the production phase. Moreover, the carbon content of liquid fuels, which is higher than that of gaseous fuels, will be responsible for higher CO2 emissions from vehicles. Currently, natural gas has poor diffusion in the transport sector, and this paper highlights the motivations for favouring a policy aimed at increasing the share of gaseous fuel-powered vehicles. In addition to the low environmental impact, synthetic natural gas also offers the possibility of optimising the utilisation of future resources.

Recent Developments in Cobalt- and Iron- Based Catalysts for Fischer- Tropsch Synthesis

This paper addresses recent technological advances for both cobalt- and iron-based Fischer-Tropsch (FT) synthesis catalysts. FT technology converts syngas into clean, synthetic liquid fuels by using abundant sources such as coal, biomass and natural gas. We provide an overview of the latest patent literature and summarize improvements in catalyst design and chemical promotion through the addition of active metals and structural supports as well as different methods for catalyst preparation and activation. We also discuss developments in reactor configuration and upstream and downstream design, and investigate the different application scenarios for both iron and cobalt catalysts. Significant progress has been realized in the past decade, evidenced by an increased number of patents focusing on catalyst and reactor advances and their effect on increasing catalyst activity and product yield and selectivity. The process can be carried out in large-scale units such as slurry bubble columns or fluidized-bed reactors, or in small compact microchannel reactor units. Combining the FT catalyst and reactor technology with innovative ways for syngas production and product upgrading to produce ready-to-use fuels results in a versatile FT technology that can be remotely applied on land or sea. This versatility can provide a long-term solution to counter the persistent increase in crude oil prices and can dramatically impact the competency and economical production of fuels worldwide. Keywords: Cobalt catalysts, co-precipitation, Fischer-Tropsch catalysis, fluidized-bed reactors, iron catalysts, incipient wetness impregnation, Sasol, slurry-bed reactors.

Fischer-Tropsch synthesis catalysts as the core of the strategy for obtaining synthetic liquid fuels

The Fischer-Tropsch synthesis is a practically significant reaction catalyzed by Fe and Co, which are active at different H2: CO ratios of 0.5 and 2, respectively. For this reason, Fe-containing catalysts are preferentially used in coal-to-liquids (CTL) and biomass-to-liquids (BTL) processes, while Co-containing catalysts are preferred for the gas-to-liquids (GTL) technology. With the Fe catalysts, which are remarkable for their high CO2 formation selectivity, it is appropriate to carry out the carbon dioxide reforming of the feedstock.

A new technology for producing synthetic liquid hydrocarbons from gaseous hydrocarbons

Conventional technologies of synthetic liquid fuels (SLF) production from gaseous hydrocarbons by producing synthesis gas and synthesizing synthetic liquid hydrocarbons are examined. A high-efficiency SLF production technology that allows creation of high-efficiency autonomous units of specific capacities, including small ones, eliminates use of oxygen for producing synthesis gas and reduces energy consumption by thorough utilization of the heat of process and energy flows, including low-potential, is described. In this technology, the hydrocarbon feedstock conversion processes and synthesis of liquid hydrocarbons are carried out with highly effective fine-grained catalysts under optimal temperature conditions in compact reactors of a new design. Efficient conversion of gaseous hydrocarbon feedstock right at the gas recovery sites to synthetic liquid fuels (SLF) holds wide prospects in solving many problems of energy security of regions. This will allow production of high-quality SLF that can be transported by conventional means (by tankers, containers, pipelines, etc.). In contrast to hydrocarbon gases, SLF can be stored and marketed by using the existing developed infrastructure [1]. Russia possesses enormous reserves of natural (NG) and associated petroleum gases (APG) and is a major supplier of energy resources to the countries of Western Europe. The largest oil and gas companies of the world have been working vigorously to develop and implement projects based on GTL (gas-to-liquid) technology in regions with substantial NG reserves [2]. Efficient conversion of NG to SLF may introduce corrections to the necessity of implementation of some costly projects. In that case: 1) there will be no need for constructing multi-kilometer trunk pipelines with compressor stations and their costly operation; 2) there will be no need for transit countries for NG transportation; 3) the seasonal NG supply factor will be solved; 4) there will be no need for building costly NG liquefying plants, special liquefied NG storing and dispatching terminals, special vessels for its transportation, receiving terminals with regasification plants, etc.; 5) the APG will be put into commercial production instead of burning in flares; and 6) noxious vehicular emissions will be reduced, which is of especial importance for solving environmental problems of large cities, and so on. Chemical and Petroleum Engineering, Vol. 48, Nos. 5‐6, Sept., 2012 (Russian Original Nos. 5‐6, May‐June, 2012)

Review of the Potential of Nuclear Hydrogen for Addressing Energy Security and Climate Change

Nuclear energy has the potential to exert a major positive impact on energy security and climate change by coupling it to the transportation sector, primarily through hydrogen production. In the short term, this coupling will provide carbon-free hydrogen for upgrading increasingly lower-quality petroleum resources such as oil sands, offsetting carbon emissions associated with steam methane reforming. In the intermediate term, nuclear hydrogen will be needed for large-scale production of infrastructure-compatible synthetic liquid fuels. In the long term, there is great potential for the use of hydrogen as a direct vehicle fuel, most likely in the form of light-duty pluggable hybrid hydrogen fuel cell vehicles (HFCVs). This paper presents a review of the potential benefits of large-scale nuclear hydrogen production for energy security (i.e., displacing imported petroleum) and reduction of greenhouse gas emissions. Life-cycle benefits of nuclear energy in this context are presented, with reference to recent major publications on this topic. The status of U.S. and international nuclear hydrogen research programs is discussed. Industry progress toward consumer-grade HFCVs is also examined.

CO2 and H2O reduction by solar thermochemical looping using SnO2/SnO redox reactions: Thermogravimetric analysis

The thermochemical dissociation of CO2 and H2O from reactive SnO nanopowders is studied via thermogravimetry analysis. SnO is first produced by solar thermal dissociation of SnO2 using concentrated solar radiation as the high-temperature energy source. The process targets the production of CO and H2 in separate reactions using SnO as the oxygen carrier and the syngas can be further processed to various synthetic liquid fuels. The global process thus converts and upgrades H2O and captured CO2 feedstock into solar chemical fuels from high-temperature solar heat only, since the intermediate oxide is not consumed but recycled in the overall process. The objective of the study was the kinetic characterization of the H2O and CO2 reduction reactions using reactive SnO nanopowders synthesized in a high-temperature solar chemical reactor. SnO conversion up to 88% was measured during H2O reduction at 973 K and an activation energy of 51 ± 7 kJ/mol was identified in the temperature range of 798-923 K. Regarding CO2 reduction, a higher temperature was required to reach similar SnO conversion (88% at 1073 K) and the activation energy was found to be 88 ± 7 kJ/mol in the range of 973-1173 K with a CO2 reaction order of 0.96. The SnO conversion and the reaction rate were improved when increasing the temperature or the reacting gas mole fraction. Using active SnO nanopowders thus allowed for efficient and rapid fuel production kinetics from H2O and CO2.

Thermochemical Dissociation of Water and Carbon Dioxide via ZnSI Cycle for Hydrogen and Carbon Monoxide Production

Thermochemical water and carbon dioxide splitting via zinc sulfur iodine (ZnSI) cycle coupling with renewable energy sources as the source of high temperature process heat, is a promising solution to produce hydrogen and carbon monoxide, which can alleviate CO2 emissions from the combustion of various fossil fuels. The synthetic liquid fuels are achieved with the combination of CO and H2. The process design of this novel approach has been carried out on the basis of six associated chemical reactions. The theoretical maximum energy conversion efficiency of the cycle has been evaluated according to basic thermodynamic laws.

An Improved Core Reaction Mechanism for Saturated C0-C4 Fuels

Accurate chemistry models are required to predict the combustion behavior of different fuels, such as synthetic gaseous fuels and liquid jet fuels. A detailed reaction mechanism contains chemistry for all the molecular components in the fuel or its surrogates. Validation studies that compare model predictions with the data from fundamental combustion experiments under well-defined conditions are least affected by the effect of transport on chemistry. Therefore they are the most reliable means for determining a reaction mechanism’s predictive capabilities. Following extensive validation studies and analysis of detailed reaction mechanisms for a wide range of hydrocarbon components reported in our previously published work (Puduppakkam et al., 2010, “Validation Studies of a Master Kinetic Mechanism for Diesel and Gasoline Surrogate Fuels,” SAE Technical Paper No. 2010-01-0545; Naik et al., 2010, “Validated F-T Fuel Surrogate Model for Simulation of Jet-Engine Combustion,” Proc. ASME Turbo Expo, Paper No. GT2010-23709; Naik et al., 2010, “Applying Detailed Kinetics to Realistic Engine Simulation: The Surrogate Blend Optimizer and Mechanism Reduction Strategies,” SAE J. Engines 3(1), pp. 241–259; Naik et al., 2010, “Modeling the Detailed Chemical Kinetics of Mutual Sensitization in the Oxidation of a Model Fuel for Gasoline and Nitric Oxide,” SAE J. Fuels Lubr. 3(1), pp. 556–566; and Puduppakkam et al., 2009, “Combustion and Emissions Modeling of an HCCI Engine Using Model Fuels,” SAE Technical Paper No. 2009-01-0669), we identified some common issues in the predictive nature of the mechanisms that are associated with inadequacies of the core (C0-C4) mechanism, such as inaccurate predictions of laminar flame speeds and autoignition delay times for several fuels. This core mechanism is shared by all of the mechanisms for the larger hydrocarbon components. Unlike the reaction paths for larger hydrocarbon fuels; however, reaction paths for the core chemistry do not follow prescribed reaction rate-rules. In this work, we revisit our core reaction mechanism for saturated fuels, with the goal of improving predictions for the widest range of fundamental experiments. To evaluate and validate the mechanism improvements, we performed a broad set of simulations of fundamental experiments. These experiments include measurements of ignition delay, flame speed and extinction strain rate, as well as species composition in stirred reactors, flames and flow reactors. The range of conditions covers low to high temperatures, very lean to very rich fuel-air ratios, and low to high pressures. Our core reaction mechanism contains thermochemical parameters derived from a wide variety of sources, including experimental measurements, ab initio calculations, estimation methods and systematic optimization studies. Each technique has its uncertainties and potential inaccuracies. Using a systematic approach that includes sensitivity analysis, reaction-path analysis, consideration of recent literature studies, and an attention to data consistency, we have identified key updates required for the core mechanism. These updates resulted in accurate predictions for various saturated fuels when compared to the data over a broad range of conditions. All reaction rate constants and species thermodynamics and transport parameters remain within known uncertainties and within physically reasonable bounds. Unlike most mechanisms in the literature, the mechanism developed in this work is self-consistent and contains chemistry of all saturated fuels.

Direct liquefaction of ligno-cellulosic residues for liquid fuel production

This study focuses on the valorization of biomass wastes in the Piedmont Region, in Italy, with the aim of producing synthetic liquid fuels. On the basis of a territorial survey, the selected fractions from the separate collection of municipal solid wastes (organic fraction, pruning residues and wood refuses) and, to a lesser extent, the residues of the agro-industry, were considered potentially important, due to their abundance and availability throughout the year. Dedicated arborous cultivations, evaluated on the basis of the land that is currently cultivated, also showed a great potential. The sum of the potential recoverable energy from these three categories reaches 35.99×106GJ/year, i.e. 6.79% of the total final energy consumption of the Piedmont Region.The target of this valorization is here the conversion of these low energy density biomasses into valuable liquid fuels. The direct liquefaction technology was chosen due to its flexibility towards the feed and the possibility of working with wet substrates, these being typical constraints which are difficult to be overcome in the other thermo-chemical processes. In the direct liquefaction process, a pulp of organic material, with a water content ranging from 50% to 90%, is fed to a reactor at around 330°C and 180bar, with a residence time of 4–10min, according to the biomass pulp composition. The resulting bio-oil can be fed to the upgrading section of a refinery, in order to reach standard fuel-grade specifications, which allows it to be blended with currently sold transportation fuels, or it could be used as a source of valuable chemicals in an alternative scenario. A 50ktons/year plant (based on the dry biomass content) was considered, and the balance of plant was sized in order to estimate the energy requirements of the plant and the bio-oil yield. A very convenient configuration was designed, and a bio-oil net production of 37.1wt% was reached (referring to the dry matter of the biomass), which takes into account all the fuel needs of the plant. The specific power consumption was equal to 0.258kWh/kgOil, which corresponds to a ratio between the output and input energy of 35.8 (excluding the biomass lower calorific value). Finally, it should be mentioned that this target was obtained using simple and economic equipment, thus responding to the need to devise a process which could be profitable, even at a medium scale, for local applications.

Process comparison of biomass-to-liquid (BtL) routes Fischer–Tropsch synthesis and methanol to gasoline

Lignocellulosic biomass is currently seen as a renewable alternative to fossil fuels in the transport sector. There are two possible routes to produce liquid hydrocarbon fuels from biomass via synthesis gas: Fischer–Tropsch (FT) synthesis and methanol to gasoline (MtG). This paper evaluates, based on chemistry and chemical engineering aspects, the process design, the economic feasibility and the process potential for both synthesis routes. FT and MtG reactions can be described under the same overall chemical equation. However, the differences between the two syntheses were found in chemical mechanism, catalyst and product distribution. The material and energy balances do not establish a clear preference for any synthesis route, the market application of the product being a key parameter. The calculated overall chemical energy efficiencies to synthetic liquid hydrocarbons (C5–C20) from biomass are 25.8–46.5% for FT and 23.4–44.4% for MtG. The calculated carbon efficiency to synthetic liquid hydrocarbons (C5–C20) ranges between 18.6% and 33.5% for FT and 17.3–32.8% for MtG. The production costs for synthetic liquid hydrocarbon fuels are calculated based on the efficiencies given above. They range between 21€ and 34€ per gigajoule. These values could drop to 18–28€ per gigajoule in the medium term based on optimistic predictions (increase of efficiencies and reduction of capital investment). If the prize difference between crude oil and biomass becomes as high as 20€ per gigajoule, the production of liquid hydrocarbons from biomass will probably become competitive with petroleum-based products.

Techno-economic evaluation of coal-to-liquids (CTL) plants with carbon capture and sequestration

Coal-to-liquids (CTL) processes that generate synthetic liquid fuels from coal are of increasing interest in light of the substantial rise in world oil prices in recent years. A major concern, however, is the large emissions of CO 2 from the process, which would add to the burden of atmospheric greenhouse gases. To assess the options, impacts and costs of controlling CO 2 emissions from a CTL plant, a comprehensive techno-economic assessment model of CTL plants has been developed, capable of incorporating technology options for carbon capture and storage (CCS). The model was used to study the performance and cost of a liquids-only plant as well as a co-production plant, which produces both liquids and electricity. The effect of uncertainty and variability of key parameters on the cost of liquids production was quantified, as were the effects of alternative carbon constraints such as choice of CCS technology and the effective price (or tax) on CO 2 emissions imposed by a climate regulatory policy. The efficiency and CO 2 emissions from a co-production plant also were compared to the separate production of liquid fuels and electricity. The results for a 50,000 barrels/day case study plant are presented.