Process Synthesis and Optimization

This supplementary information includes the following sections: S1. Chemical conditions for the NPs production S2. XRD characterization of the synthesized NPs S3. XPS, XANEs and Fourier transform EXAFS of the NPs S5. PLQY measurements S4. Dose dependent experiment and performance comparison between optimized NPs and commercially available NPs

Hydroelectricity is an important component of world renewable energy supply and remains a major source of power generation due to its environment friendly nature. Effective water management improves the efficiency of utilization of reservoir with social and environmental safety. A suitable reservoir control strategy can lead to large benefits in electrical production and irrigation. Hence it is necessary to study the system for finding an operational model guide. The dynamic system modeling of power network located in the mountain region of Valle d’Aosta in North Western Italy is presented. The Powersim simulation tool is used to construct such a model. Modeling is based on reservoir elevation, mean data of reservoir inflow, and turbine discharges as main description variables. Runoff production of catchments slope gives the reservoir capacity to fit perfectly. Inflow includes contribution of rainfall, glacier meltdown, and other secondary streams. Based on such a modeling framework...

This work presents an optimisation framework for the routing and equipment design of main pipelines to be used for fluid transmission. There are many considerations in these design problems, involving various constraints, decisions and the associated costs for the construction, operation, maintenance, etc, of the system. In practice, engineers rely on experience, try out various design alternatives, and use simulators for engineering calculations, cost models, geographical information systems and equipment databases to identify promising options. The present approach proposes a systematic search for optimal and near-optimal solutions. The search is based on stochastic optimisation, and assumes that the same information and simulation tools as in the case of design by trial and error are available. An application example is used to demonstrate the approach and test the robustness of the optimal search using Simulated Annealing.

In the present research, multi-objective optimization (MOO) was applied to a natural gas-to-liquids (GTL) process with a multi-stage Fischer-Tropsch (FT) reactor. A CO 2 stream was fed into the GTL plant's endothermic steam reformer (SMR) to adjust the H 2 to CO ratio of the SMR effluent. Three objective functions were considered in this paper; minimizing the amount of CO 2 released to the atmosphere, maximizing carbon efficiency, and maximizing wax production. The degrees of freedom for the GTL process with single-stage FT reactor were recycle ratio to process and recycle ratio to the FT reactor. In addition, for the GTL process with two-stage FT reactor, the synthesis gas split ratio between the stages was considered as another degree of freedom. Maximizing wax production rate results in lower carbon efficiency and higher CO 2 emission to the atmosphere. The amount of CO 2 intake to the SMR in all cases was 256 tons/hr. With the same amount of utilized CO 2 in the SMR, sectioning of the FT reactor to two similar stages notably increases the carbon efficiency and mass flow of wax compared to the single stage case.

The optimal design of a natural gas‐to‐liquid hydrocarbons (GTL) process with a multistage cobalt‐based Fischer‐Tropsch reactor and interstage product separation is considered. The objective function is to maximize the wax (C21+) production rate at the end of the reactor path. Sectioning of the Fischer‐Tropsch reactor increases the chain growth probability inside the reactor which results in a higher production of wax. The carbon efficiency of the two‐stage reactor is distinctly higher than that of the single‐stage reactor.

This study of gas to liquid (GTL) production uses an authothermal reformer (ATR) for synthesis gas production and a slurry bubble column reactor (SBCR) with Cobalt catalyst for the Fisher-Tropsch (FT) conversion to liquid fuels. The well-known Satterfield kinetics are used for the FT reactor; the remaining reactions are simulated assuming thermodynamic equilibrium. The process also includes high-pressure CO 2 removal. Important process parameters, which are subject to optimization, include feed rates of water and oxygen, inlet ATR temperature and recycle flows. In addition to determining the process and equipment design, optimization is used to find the controlled variables. The aim is to identify "self-optimizing variables" that indirectly give close-to-optimal operation with constant setpoints, in spite of disturbances.

The design and optimization of a natural gas to hydrocarbon liquids (GTL) process is considered, mainly from the view of maximizing the variable income during operation. Autothermal reforming (ATR) is used for synthesis gas production. The kinetic model for FischerÀTropsch (FT) reactions is the one given by Iglesia et al. for a cobalt-based FT reactor. For the product distribution, three alternative expressions for the chain growth factor α are compared.

A simplified transient model for fixed-bed reactors was extended to account for the heat sink effect of the phase change material diluent in the Fischer-Tropsch reactor energy balance. The resulting model was found to accurately approximate the more rigorous two-dimensional model with significantly less computational requirements even at the hotspot, where the reactor enthalpy balance is most sensitive. As anticipated, the presence of the encapsulated phase change material in the reactor induced thermal inertia, thereby restricting the temperature ramp rate in the reactor to acceptably safe operational limits for the catalyst. Although there was a reduction in both the CH 4 and C 5+ productivity, the reduction in CH 4 production was up to four times that of the C 5+ at the same coolant temperature.

In this paper, a methodology for systematically integrating the synthesis of combined heat, mass, and regeneration exchange networks with solar thermal is presented. The process considered involves the removal of ammonia from ammonia-rich gaseous streams using water-based solvents as the mass separating agent (MSA) and subsequent regeneration of the ammonia-rich MSA stream using steam stripping. A composite superstructure, which comprises the stage-wise superstructure for the synthesis of the heat exchanger network subsystem, primary mass exchanger network subsystem, regeneration subsystem and integrated solar thermal with periodic heat storage, is developed. In order to simplify the modelling of the unpredictable availability of solar thermal energy within the composite superstructure, a multi-periodic synthesis approach is adopted. Sensitivity analysis was performed to establish the price at which solar thermal is favoured over fossil-derived energy as the hot utility source. The economics of the resulting solution is evaluated using net present value, and it was found that, to obtain a positive NPV, the stripping cost in the retrofitted network will have to be as low as possible, or annual operating cost of the non-retrofitted primary mass exchange network will have to be high.

We present a new method for the synthesis of mass exchanger networks (MENs) involving packed columns. Simultaneous synthesis of MENs is typically done through the use of mixed-integer nonlinear program (MINLP) optimization, with simplifications made in the mathematical representations of the exchangers due to computational difficulty in solving large non-convex mixed-integer problems. The methodology proposed in this study makes use of the stage-wise based superstructure MINLP formulation for the network synthesis. This stage-wise superstructure model incorporates fixed mass transfer coefficients, fixed column diameters, no pressure drops, and unequal compositional mixing for models. In this paper, the simplified MINLP model is further improved by including a detailed individual packed column design in a non-linear programming (NLP) sub-optimisation step, where orthogonal collocation is utilized for the partial differential equations, and optimal packing size, column diameter, column height, pressure drops, and fluid velocities. Detailed designs are then used to determine correction factors that update the simplified stage-wise superstructure models to more accurately portray the chosen design. Once the MINLP is updated with these correction factors, the model is rerun , with new correction factors obtained. This iterative procedure is repeated until convergence between the objective function of the MINLP and that of the NLP sub-optimisation is achieved, or until a maximum number of iterations is reached. The methodology is applied to two examples and is shown to be robust and effective in generating new topologies, and in finding superior networks that are physically realizable.

Mass exchange network synthesis (MENS) can be used to reduce pollutant emissions into the environment as well as reduce the need for mass separating agents (MSAs). Designing an efficient network using mathematical programming is not a trivial task, due to the fact that the design equations involved are highly non-linear. Chemical plant process parameters also change from time to time due to issues such as changes in environmental conditions, plant start-up/shut-downs, changes in process feed quality, change in product quality demand, and some other disturbance in the system. Such changes in process parameters result in what is known as multi-period operations; hence the synthesised network has to be flexible to handle these changes. In order to circumvent the issues associated with solving non-linear equations in mathematical programming environment, most methods have simplified the cost functions for MENS. Solutions obtained from these methods may not be realistic because the simplified cost functions are based on the assumption that the diameter of a column is 1 m or 2 m and that the capital cost of packed columns are dependent only on the height of the column. The simplified models do not make provision to check whether the resulting designs are prone to flooding, operate at optimal pressure drops or even whether the ratio of column diameter to size of packing materials would enhance efficient operations. Furthermore the models assumed single period operations for mass exchange network systems. This paper presents a new synthesis method for single and multi-period MENS using detailed cost functions and correlations which check whether selected columns are prone to flooding or not and whether they have optimal pressure drops that ensure efficient separations as well as optimal use of MSAs. The solutions obtained are compared with an existing method that used pinch technology.

Currently, most of the biodiesel is produced from the edible/refined type oil using methanol and alkaline catalyst. However, large amount of non-edible type oils and fats are available in our country. In this study, crude neem oil is used as alternative fuel for biodiesel production. The difficulty with alkaline transesterification of these oils have contained large amounts of free fatty acids (FFA). These free fatty acids quickly react with the alkaline catalyst to produce soaps that inhibit the separation of the ester and glycerin. A two-step transesterification process is developed to convert the high FFA oils to its mono-esters. Using 100 ml of oil,the optimum combination of parameters for pretreatment were found to be .45 v/v methanol-oil-ratio,0.5%v/w H2SO4 acid catalyst, 50˚C and 45 min reaction time. After pretreatment of neem oil,transesterification reaction was carried out with 0.3:1 methanol-tooil ratio, 1%KOH as alkaline catalyst,1hr reaction time and 55˚C reaction tempe...

This article has been accepted for publication and undergone full peer review but has not been through the copyediting, typesetting, pagination and proofreading process, which may lead to differences between this version and the final Version of Record (VOR). This work is currently citable by using the Digital Object Identifier (DOI) given below. The final VoR will be published online in Early View as soon as possible and may be different to this Accepted Article as a result of editing. Readers should obtain the final VoR from the journal website shown below when it is published to ensure accuracy of information. The authors are responsible for the content of this Accepted Article.

The design and optimization of a natural gas to hydrocarbon liquids (GTL) process is considered, mainly from the view of maximizing the variable income during operation. Autothermal reforming (ATR) is used for synthesis gas production. The kinetic model for FischerÀTropsch (FT) reactions is the one given by Iglesia et al. for a cobalt-based FT reactor. For the product distribution, three alternative expressions for the chain growth factor α are compared.

Five placements of a CO 2 removal unit in a gas-to-liquid (GTL) process are evaluated from an economical point of view. The kinetic model is the one given by Iglesia et al. for a cobalt-based Fischer-Tropsch (FT) reactor. For each alternative, the process is optimized with respect to steam-to-carbon ratio, purge ratio of light ends, amount of tail gas recycled to syngas and FT units, reactor volume, and CO 2 recovery. The results indicate that carbon and energy efficiencies and the annual net cash flow of the process with or without CO 2 removal unit are not significantly different, and that there is not much to gain by removing CO 2 from the process. It is optimal to recycle about 97 % of the light ends to the process (mainly to the FT unit) to obtain higher conversion of CO and H 2 in the reactor.

Biodiesel is a non-toxic, renewable and biodegradable alternative fuel and this can be used without any engine modifications. Biodiesel can be used as fuel in the form of purest form to the vehicle; it can be used as diesel additive to reduce particulates like Carbon monoxide and Hydrocarbons. The purpose of this project is to investigate the effect of Bio fuel produced from non-edible oils on engine performance and emissions. Biodiesel was prepared from non-edible oil such as SIMAROUBA OIL by Tran's esterification method. After Tran's esterification process, the properties of Simarouba oil biodiesel and Diesel was compared. From this comparison, it is observed that properties of Simarouba oil Biodiesel are better than the raw oils. Tests were carried out on 4-S CI Diesel engine without any modification in the fuel injection system. From the results, it is observed that the Simarouba oil Biodiesel performance results comparable to Diesel fuel. Also Biodiesel fuel results in ...

Cucumis sativus L. seeds oil was extracted by an organic solvent and analyzed for its physicochemical properties i.e. acid value, iodine value, moisture content, density and refractive index. The acid value, moisture content and iodine value were 1.581 mg KOH/g oil, 0.108% and 125.26 gI2/100 g respectively. The density and refractive index of the oil were found to be 0.8977 g/cm 3 and 1.4685 respectively. Gas chromatographic analysis of Abelmoschus esculentus seeds oil showed that unsaturated fatty acids such as linoleic acid (54.31 wt.%) and oleic acid (22.27 wt.%) account for more than 70% of total fatty acids. The prominent saturated fatty acid present is palmitic acid (19.43 wt.%).

Commercial success in the photonics marketplace dictates a full understanding of the product development lifecycle. Underpinning this success is the maximization of performance and minimization of product development time. These can be afforded at an early stage by employing computer design

As a renewable, biodegradable, and non-toxic fuel, biodiesel has attracted a lot of attention during the past century. It is a methyl ester of a fatty acid made from triglycerides by the methanol transesterification process. Due to the alarming rise in automobile ownership over the past year, there is now more focus on finding alternatives to diesel fuel as both demand and costs for petroleum goods have increased. The majority of biodiesel is currently made from refined or oil seeds using an alkaline catalyst and methanol. Large quantities of oil and fat, however, cannot be ingested. However, it is realistic to use a lot of nonedible oil and fat in our nation. Neem oil is utilized in this study as an alternate fuel to create biodiesel. By combining high-free fatty acid (FFA) oil with the best methanol and H2SO4 acid catalyst properties, biodiesel is created utilizing this process using methanol and KOH catalyst.

A typical methanol loop reactor is analyzed in this study. All basic equipment in the Lurgi-type methanol loop is included in the proposed model. A detailed dynamic model described by a set of ordinary differential and algebraic equations is developed to predict the behavior of the overall process. The model is validated against plant data. A new deactivation model is proposed and its parameters are estimated using daily plant data. The interesting feature of this model is that it incorporates the effect of carbon dioxide and carbon monoxide on the catalyst deactivation. Using the model, the effect of various factors to compensate for the reduction of production rate due to catalyst deactivation has been examined. Some improvements can be achieved by adjusting the operating conditions. Finally, a strategy is proposed for prevention of reduced production due to catalyst deactivation.

In the current scenario, the energy sector of the developing world depends on fossil fuels. To reduce fossil fuel dependence, it is essential to develop new alternative energy source which can replace fossil fuels. Biodiesel is an effective approach that can replace conventional fossil fuels. Mahua biodiesel is produced from Raw Mahua oil by simple transesterification method. This experiment shows biodiesel production from raw Mahua oil with methanol instead of alcohol and KOH as a catalyst. Fuel properties of Mahua biodiesel are compiled in accordance with European (EN) and American (ASTM) standardization for testing of biodiesel and cold flow properties are further improved by blending Mahua biodiesel with ethanol. B20 blends of ethanol and Mahua biodiesel shows good pour properties.

This work presents an optimisation framework for the routing and equipment design of main pipelines to be used for fluid transmission. There are many considerations in these design problems, involving various constraints, decisions and the associated costs for the construction, operation, maintenance, etc, of the system. In practice, engineers rely on experience, try out various design alternatives, and use simulators for engineering calculations, cost models, geographical information systems and equipment databases to identify promising options. The present approach proposes a systematic search for optimal and near-optimal solutions. The search is based on stochastic optimisation, and assumes that the same information and simulation tools as in the case of design by trial and error are available. An application example is used to demonstrate the approach and test the robustness of the optimal search using Simulated Annealing.

Most of the current research in process synthesis focus on heat exchanger network synthesis. Reports on mass exchanger network synthesis mostly discussed singlecomponent problems using simultaneous approaches. However, less attention has been given to mass exchanger network synthesis with multi-component problems using the sequential technique. Till date, it has not been easy to systematically choose between the process and available external mass separating agents (MSA) in mass exchanger network synthesis during the adsorption of CO 2 . In this paper, we set out a technique for targeting external mass separating agent and its network design. The technique was applied to a CO 2 adsorption process involving two mass separating agents (process and external MSAs) that overlap. A thermodynamic analysis of the CO 2 adsorption process was outlined in this study using the composition interval method. Feasible structures were formulated and the synthesis task was expressed in a two-stage targeting procedure as an optimization task. Unlike previous studies reported in the past for mass exchanger network synthesis, this contribution considers a trade-off between the process MSA S 1 and external MSA S 2 to determine the minimum amount of external MSA required for the CO 2 capture process. A case study was adapted from open literature to demonstrate the effectiveness of the synthesized mass exchanger network during a typical CO 2 capture process. Outcomes from this study indicate that mass integration via process synthesis is an effective strategy that can minimize the quantity of external utilities required during the adsorption of CO 2 from a rich stream of flue gas.

Traditional System-on-Chip (SoC) design employed shared buses for data transfer among various subsystems. As SoCs become more complex involving a larger number of subsystems, traditional bus-based architecture is giving way to a new paradigm for on-chip communication. This paradigm is called Network-on-Chip (NoC). A communication network of point-to-point links and routing switches is used to facilitate communication between subsystems. The routing switch proposed in this paper consists of four components, namely the input ports, output ports, switching fabric, and scheduler. The scheduler design is described in this paper. The function of the scheduler is to arbitrate between requests by data packets for use of the switching fabric. The scheduler uses an improved round robin based arbitration algorithm. Due to the symmetric structure of the scheduler, an area-efficient design is proposed by folding the scheduler onto itself, thereby reducing its area roughly by 50%.

A typical methanol loop reactor is analyzed in this study. All basic equipment in the Lurgi-type methanol loop is included in the proposed model. A detailed dynamic model described by a set of ordinary differential and algebraic equations is developed to predict the behavior of the overall process. The model is validated against plant data. A new deactivation model is proposed and its parameters are estimated using daily plant data. The interesting feature of this model is that it incorporates the effect of carbon dioxide and carbon monoxide on the catalyst deactivation. Using the model, the effect of various factors to compensate for the reduction of production rate due to catalyst deactivation has been examined. Some improvements can be achieved by adjusting the operating conditions. Finally, a strategy is proposed for prevention of reduced production due to catalyst deactivation.

unit for airconditioning (AC) with the provision to sequester carbon-dioxide by incorporating a roller, coated with modified epomin, cross-linked with epichlorohydrin. The work presents a concept paper on the use of epomin as adsorbent in a residential AC device. The design of the unit has been optimized to show how the sequestration process takes place inside the air conditioner. It is proposed that the desorption of the CO 2 from the adsorbent can be carried out using solar concentrators. The stored carbon-dioxide can be transported to a secondary storage unit where it can be used for algal growth. The remaining gases are converted to fuel (methanol) using photochemical cell and as mineral carbonates. The method appears to be a 'green friendly' approach and can be applied for household units.

The Fischer-Tropsch synthesis (FTS) in gaseous and supercritical phases was examined in a continuous, high-pressure fixed-bed reactor by employing a cobalt catalyst (Co-Ru/c-Al 2 O 3). The kinetic modeling of the FTS was investigated in the reactor over a 60-80 mesh cobalt catalyst. The Langmuir-Hinshelwood kinetic equation was used for both the Fisher-Tropsch (FT) and water gas shift (WGS) reactions. The kinetic model was applied for simulation of the reactor with 16-20 mesh cobalt catalyst. The simulation results showed a good agreement with the experimental data. The experimental data showed that higher CO conversion and lower CH 4 and CO 2 selectivities were achieved in supercritical media compared to the gaseous phase. The BET surface area and pore volume enhancement results provided evidence of the higher in situ extraction and greater solubility of heavy hydrocarbons in supercritical media than in gaseous phases. Furthermore, the effects of supercritical solvent such as n-pentane, n-hexane, n-heptane and their mixtures were studied. Moreover, the influence of reaction temperature, H 2 /CO ratio, W/F (CO+H2) and pressure tuning in the supercritical media FT synthesis were investigated, as well as the effect of the supercritical fluid on the heat transfer within the reactor. The product carbon distribution had a similar shape for all types of solvents and shifted to lighter molar mass compounds with increasing temperature, H 2 /CO ratio, and W/F (CO+H2). Finally, the product distribution shifted to higher molar mass hydrocarbons with increasing pressure. As a result, one may conclude that a mixture of hydrocarbon products of the FTS can be used as a solvent for supercritical media in Fischer-Tropsch synthesis.

The consumption of edible oil is very high in the country and still the indigenous production does not meet the demand and considerable amount of edible oil is imported. Also, it is not advisable to divert these sources for biodiesel production. On the other hand, the non-edible oil resources could be a solution for biodiesel production. Non-edible oil from the plant seeds is the most promising alternative fuel for internal combustion engine because it is renewable, environment friendly, non-toxic, biodegradable has no sulphur and aromatics, has favourable combustion value and higher cetane number. Extensive work has been done on the transesterification of non-edible oils; however, no significant work has been done on the optimization of transesterification process, oil characterization and fuel analysis of most of the non-edible seed oils. Low cost and abundantly found non-edible oils such as Neem oil could be a better option for biodiesel processing. In the present work, optimization of transesterification process and analysis of biodiesel from non-edible oil was done; based on optimized protocol for biodiesel production from Neem seed oil converted into fatty acid methyl esters (FAME) through base catalyzed trans esterification using an optimum ratio of 1:6 (Oil : Methanol) at 60 0 C. Biodiesel from these sources was analyzed for qualitative and quantitative characterization by using, GC-MS and FT-IR techniques. Based on qualitative and quantitative analysis of biodiesel, it is concluded that the biodiesel from these species can be feasible, cost effective and environment friendly.

This work presents an optimisation framework for the routing and equipment design of main pipelines to be used for fluid transmission. There are many considerations in these design problems, involving various constraints, decisions and the associated costs for the construction, operation, maintenance, etc., of the system. In practice, engineers rely on experience, try out various design alternatives, and use simulators for engineering calculations, cost models, geographical information systems and equipment databases to identify promising options. The present approach proposes a systematic search for optimal and near-optimal solutions. The search is based on stochastic optimisation, and assumes that the same information and simulation tools as in the case of design by trial and error are available. An application example is used to demonstrate the approach and test the robustness of the optimal search using Simulated Annealing.

This project would not have been possible without the help and support of many people. First and Foremost, I would like to express my sincere gratitude to the almighty God for seeing me through thick and thin times during my study at this wonderful institution. Secondly, I would like to thank my supervisor Prof. Sigurd Skogestad for the continuous support he offered me during my MSc. studies, for his patience, motivation, enthusiasm, and immense knowledge. His guidance helped me in all the time of my research and writing of this thesis. I could not have imagined having a better advisor and mentor for my master program. Besides my advisor, I would like to thank my co-supervisor Mehdi Panahi, for his encouragement, insightful comments, hard questions and for steering me towards the right direction all the time. My sincere thanks also go to Prof. Heinz Preisig, Prof. Magne Hillestad, Prof. Jens-Petter Andreassen and Lisbeth Roely, and all the other members of the department. I thank my fellow international students Emmanuel Mba, Aderonke Adedeji, Trimaharika Widarena, and Bicheng Gao. Also I thank the Ghanaian community in Trondheim especially Miriam Peprah, Joseph Armoo, Noble Arden Nkuadey and all the rest for their support and advice. Last but not the least; I would like to thank my family: my wife Joyce Asare Arthur and my parents John Yalley-Arthur and Helena Eshun, for giving birth to me at the first place and supporting me spiritually throughout my life.

This project would not have been possible without the help and support of many people. First and Foremost, I would like to express my sincere gratitude to the almighty God for seeing me through thick and thin times during my study at this wonderful institution. Secondly, I would like to thank my supervisor Prof. Sigurd Skogestad for the continuous support he offered me during my MSc. studies, for his patience, motivation, enthusiasm, and immense knowledge. His guidance helped me in all the time of my research and writing of this thesis. I could not have imagined having a better advisor and mentor for my master program. Besides my advisor, I would like to thank my co-supervisor Mehdi Panahi, for his encouragement, insightful comments, hard questions and for steering me towards the right direction all the time. My sincere thanks also go to Prof. Heinz Preisig, Prof. Magne Hillestad, Prof. Jens-Petter Andreassen and Lisbeth Roely, and all the other members of the department. I thank my fellow international students Emmanuel Mba, Aderonke Adedeji, Trimaharika Widarena, and Bicheng Gao. Also I thank the Ghanaian community in Trondheim especially Miriam Peprah, Joseph Armoo, Noble Arden Nkuadey and all the rest for their support and advice. Last but not the least; I would like to thank my family: my wife Joyce Asare Arthur and my parents John Yalley-Arthur and Helena Eshun, for giving birth to me at the first place and supporting me spiritually throughout my life.

The different potential sources of methane to be transformed into value commercial products are identified. The Technologies as steam reforming, selective oxidation, membrane reforming and thermal plasma are described. An analysis of the possibility of conversion of methane from anaerobic reactors and sanitary landfills into liquid hydrocarbon is done.

Most of the current research in process synthesis
focus on heat exchanger network synthesis. Reports on mass
exchanger network synthesis mostly discussed singlecomponent problems using simultaneous approaches.
However, less attention has been given to mass exchanger
network synthesis with multi-component problems using the
sequential technique. Till date, it has not been easy to
systematically choose between the process and available
external mass separating agents (MSA) in mass exchanger
network synthesis during the adsorption of CO2. In this paper,
we set out a technique for targeting external mass separating
agent and its network design. The technique was applied to a
CO2 adsorption process involving two mass separating agents
(process and external MSAs) that overlap. A thermodynamic
analysis of the CO2 adsorption process was outlined in this
study using the composition interval method. Feasible
structures were formulated and the synthesis task was
expressed in a two-stage targeting procedure as an
optimization task. Unlike previous studies reported in the past
for mass exchanger network synthesis, this contribution
considers a trade-off between the process MSA S1 and external
MSA S2 to determine the minimum amount of external MSA
required for the CO2 capture process. A case study was
adapted from open literature to demonstrate the effectiveness
of the synthesized mass exchanger network during a typical
CO2 capture process. Outcomes from this study indicate that
mass integration via process synthesis is an effective strategy
that can minimize the quantity of external utilities required
during the adsorption of CO2 from a rich stream of flue gas.

Oil was extracted from Balanite aegyptiaca (Desert Dates) using Soxhlet extraction method. The physicochemical properties of oil such as specific gravity, saponification value, acid value , free fatty acid, viscosity were determine and found to be closer to standard value. Biodiesel was produced from desert dates oil (DDO) using trans-esterification method with methanol and sodium hydroxide as catalyst. Three variable were considered at two levels 2 4 experimental design. The operated condition are methanol oil ratio (3:1-9:1) catalyst concentration (0.5%-0.9%) and Temperature (50 o C-75 o C). From the RSM quadratic polynomial equation was obtained through multiple regression analysis for the production of optimum response for the yield of Biodiesel. The results obtained shows the average optimum yield of 94.5% in the methanol oil ration 7:1, catalyst concentration 0.9% and a temperature of 60 o C respectively. Also the Blend biodiesel (B20) was produce at optimum condition and the cetane number was determine in higher temperature as 77.7 at 70 o C with catalyst concentration of 0.9% and oil ratio 7:1

Gas-to-liquid (GTL) processes are becoming attractive due to the increasing price of crude oil. Process simulation analysis on the integrated GTL process is essential as part of an extended process integration analysis of the research subjects. The two sub-process models for the GTL process, i.e., the syngas generation process and the Fischer Tropsch synthesis (FTS) process, are analyzed in detail with AS-PEN Plus. The autothermal reforming process (ATR) is analyzed using Aspen Plus based on the Gibbs reactor model, while FTS is simulated with ASPEN Plus based on detailed kinetic models for industrial iron and cobalt catalysts. Integrated GTL processes with iron and cobalt-based catalysts were simulated using ASPEN Plus. The optimal flowsheet structures were selected for each catalyst based on the overall performance in terms of thermal and carbon efficiency and product distributions. For the cobalt-based catalyst, the full conversion concept without CO 2 removal from the FT tail gas is optimal. On the other hand, the once-through concept with two series reactors and CO 2 removal from raw syngas is considered optimal for the iron-based catalyst. The thermal efficiency to crude products is likely to be ca. 60 % for the cobalt-based catalyst, whereas it is in the range of 49-55 % for the iron-based catalyst. The carbon efficiency using the water-gas shift reaction is lower using the iron-based catalyst (61-68 %) than the cobalt-based catalyst (73-75 %). As expected, the cobalt-based catalyst is more active and selective, which offers better selectivity towards C 5 + (75-79 %). The selectivity towards C 5 + for the iron-based catalyst lies in the range 63-75 %.

Adsorption technology due to its potentially low energy consumption, simple operation and flexibility in design to meet different demands is fast becoming popular and is now widely considered in the area of CO 2 capture. Adsorbents play a vital role in any adsorption technology. Therefore, the behavior of adsorbents under different conditions during an adsorption process needs to be investigated. In this study, the behavior of polyaspartamide as an adsorbent during post-combustion CO 2 capture was investigated using kinetic and non-kinetic models. Bohart-Adams and Thomas models were the non-kinetic models explored to ascertain whether external mass transfer dominated the overall system kinetics during the CO 2 adsorption onto polyaspartamide. The kinetics of adsorption of polyaspartamide was studied using Lagergen's

A method to rigorously identify the performance limits of a reactive separator network is presented in this paper. The quantification of the enhancement potential for a given technology can greatly benefit process intensification studies in the pursuit of radical improvements. The Infinite DimEnsionAl State-Space (IDEAS) conceptual framework is first reviewed and then shown to be capable of assessing the potential for process intensification of reactive separation processes. The IDEAS framework is employed to formulate an infinite linear program (ILP) that can synthesize optimal reactive separation networks, and establish rigorous tradeoffs between total network reactive holdup, and total network capacity. The proposed reactive separation process intensification method is demonstrated on a case study involving the metathesis of 2-pentene through reactive distillation. Significant intensification over prior designs is demonstrated.

The present study was undertaken to understand the fundamentals of recycling the tail gas during the Fischer-Tropsch Synthesis with an iron-based catalyst with particular emphasis on the importance of the usage ratio. The usage ratio was ca. 1.4 for the catalyst studied at our reaction conditions (240°C, 20 bar, 5000 mL/ (g cat ‚h)). The study shows the H 2 /CO ratio in the recycle gas fed to the reactor depends on both the H 2 /CO ratio in the fresh feed and the usage ratio of the catalyst. For an H 2 /CO in the fresh feed higher than the 1.4, the H 2 /CO ratio in the reactor increases with the increasing recycle ratio whereas the converse is true for H 2 /CO ratios lower than 1.4. For negligible change in the Fischer-Tropsch selectivity during external recycle, the H 2 /CO ratio in the fresh feed should match the usage ratio of the catalyst. The presence CO 2 in this recycled gas did not change the overall CO 2 selectivity; hence, CO 2 is regarded as an inert at these conditions.

Interest in the gas-to-liquid process (GTL) using Fischer-Tropsch reactors (F-T) has increased in recent years because of its potential to replace ordinary petroleum with sulfur-free fuels. However, the efficiency of the process is still low compared with current routes; a large amount of the initial exergy of the gas is used to convert it into liquid fuel. In the present study, we analyze the overall thermodynamic efficiency of a GTL process and point out the main sources of entropy production. Next, we use exergy analysis to establish the impact of catalyst selectivity and of thermal losses on the process efficiency. In particular, we report the effect of selectivity losses in the F-T reactor and reformer, and the impact of high-temperature heat integration across the reforming unit. Schematic flowsheet (power plant and ASU not shown).

The optimal design of a natural gas to liquid hydrocarbons (GTL) process with multi stage cobalt-based Fischer-Tropsch reactor and inter-stage product separation is considered. The objective function is to maximize the wax (C21+) production rate at the end of reactor path. Sectioning of the FT reactor increases the chain growth probability inside the reactors, which results in producing more wax. Carbon efficiency of the two stage reactor is 5.8% higher than single stage reactor.

CHEMICAL ENGINEERING TRANSACTIONS Volume 21, 2010 Editor JJ Klemeš, HL Lam, PS Varbanov Copyright © 2010, AIDIC Servizi Srl, ISBN 978-88-95608-05-1 ISSN 1974-9791 DOI: 10.3303/CET1021028 ... Please cite this article as: De Castro J., Rivera-Tinoco R. ...

Interest in the gas-to-liquid process (GTL) using Fischer-Tropsch reactors (F-T) has increased in recent years because of its potential to replace ordinary petroleum with sulfur-free fuels. However, the efficiency of the process is still low compared with current routes; a large amount of the initial exergy of the gas is used to convert it into liquid fuel. In the present study, we analyze the overall thermodynamic efficiency of a GTL process and point out the main sources of entropy production. Next, we use exergy analysis to establish the impact of catalyst selectivity and of thermal losses on the process efficiency. In particular, we report the effect of selectivity losses in the F-T reactor and reformer, and the impact of high-temperature heat integration across the reforming unit. Schematic flowsheet (power plant and ASU not shown).

Five placements of a CO2 removal unit in a gas-to-liquid (GTL) process are
evaluated from an economical point of view. The kinetic model is the one given
by Iglesia et al. for a cobalt-based Fischer-Tropsch (FT) reactor. For each alternative,
the process is optimized with respect to steam-to-carbon ratio, purge ratio
of light ends, amount of tail gas recycled to syngas and FT units, reactor volume,
and CO2 recovery. The results indicate that carbon and energy efficiencies and
the annual net cash flow of the process with or without CO2 removal unit are not
significantly different, and that there is not much to gain by removing CO2
from the process. It is optimal to recycle about 97% of the light ends to the process
(mainly to the FT unit) to obtain higher conversion of CO and H2 in the
reactor.

Different syngas configurations in a gas-to-liquid plant are studied including
autothermal reformer (ATR), combined reformer, and series arrangement of gasheated
reformer and ATR. The Fischer-Tropsch (FT) reactor is based on a cobalt
catalyst and the degrees of freedom are steam-to-carbon ratio, purge ratio of light
ends, amount of tail gas recycled to synthesis gas (syngas) and FT synthesis units,
and reactor volume. The production rate of liquid hydrocarbons is maximized
for each syngas configuration. Installing a steam methane reformer in front of an
ATR will reduce the total oxygen consumption per barrel of product by 40%
compared to the process with only an ATR. The production rate of liquid hydrocarbons
is increased by 25.3% since the flow rate of the purge stream for the ATR
is the highest one compared to other configurations and contains mainly CO2.