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Solid oxide fuel cells (SOFCs) are a promising next-generation technology for power production from fossil fuels. Because they convert chemical energy into electricity electrochemically, they are generally more efficient than combustion-based power plants due to the thermodynamic limitations of combustion cycles, and accordingly, have lower carbon intensities. However, one of the major drawbacks of SOFCs is that they degrade over time, and the degradation rate varies with different operating conditions. When operated in constant power mode (the most common way of baseload power production), the degradation rate is fast such that the lifetime of the SOFC stack is around one tenth of that when in constant voltage mode (in which the power output from SOFC stack decreases). To achieve baseload power production and a long lifetime simultaneously, one potential solution is to integrate SOFC stack (operated in constant voltage mode) with a gas turbine (GT) in a SOFC/GT hybrid system. As the SOFC stack degrades, the power produced from GT increases over time by using the increasing heating value of the unspent fuel from the SOFC exhaust. We performed an eco-technoeconomic analysis (eTEA) of the SOFC/GT concept with degradation in comparison with the SOFC standalone system. The results of model simulations showed that, with certain operating conditions, the SOFC/GT hybrid system was around 36% more efficient than the SOFC standalone system, and also had about 18 times longer lifetime. On a 550 MW scale and 30-year-lifetime, SOFC/GT hybrid system can reduce the levelized cost of electricity (LCOE) by around 80 % as well as CO2 emission by around 27 %, compared to the SOFC standalone system. The results show that SOFC/GT hybrids are a promising near-term approach because existing SOFC technology can be used directly while both avoiding short cell lifetimes and still getting near-baseload performance.

The petroleum coke gasification integrated gasification combined cycle power plant (petcoke-IGCC) is a promising avenue for disposal of the ever-growing amount of stockpiled petroleum coke. In this work, we present a novel techno-economic and life cycle assessment of the process operated with carbon capture and sequestration. The proposed petcoke-to-electricity plant is designed and simulated in Aspen Plus v10. The proposed power plant was compared against coal integrated gasification combined cycle (coal-IGCC) and supercritical pulverized coal power plants operated with carbon capture and sequestration. The results showed that although the efficiency of the coal-IGCC plant is higher than the petcoke-IGCC plant, the higher energy density of the petcoke and lower resource costs were such that the levelized cost of electricity of petcoke-IGCC was lower than coal-IGCC. Furthermore, the feed flow rate of petcoke to the petcoke-IGCC process is approximately 15% lower than the coal feed rate to coal-IGCC in order to produce the same net electric power. In addition, the life cycle greenhouse gas emissions and fossil fuel depletion of the petroleum coke integrated gasification combined cycle power were around 43% and 45% lower than the supercritical pulverized coal power plants respectively. Overall, the proposed petcoke-IGCC power plant showed to be a feasible avenue by which an environmentally safe “end of life” of petroleum coke can be achieved.

This work presents a novel study on the life cycle assessment of Fischer-Tropsch diesel (FTD) production via petroleum coke (petcoke) gasification with and without carbon capture and sequestration (CCS). A detailed analysis which focuses on evaluating and quantifying the well-to-wheel (WTW) environmental impacts of converting petcoke to FTD and its subsequent combustion is discussed. The overall process inventory includes mass and energy balances data from our Aspen Plus model, the US Life Cycle Inventory Database, and the GREET model. Life cycle impact assessment (LCIA) categories of the petcoke-derived diesel (PDD) were calculated using TRACI 2.1 v1.04 in SimaPro 8.5.0.0 which is compared against both conventional petroleum and oil-sands derived diesel. In addition, two different plant locations in Canada (Alberta and Ontario) which respectively have very high and low electricity grid emissions were considered as they are representative of grid emissions across the world. Results of the analysis showed an overall reduction in fossil fuel depletion of up to 80% and 83% for Alberta and Ontario respectively when compared to the fossil derived diesel. When operated with CCS, the WTW GHG emissions were 7% lower than conventional petroleum diesel and 18% lower than oil-sands diesel for the plant located in Ontario. However, when located in Alberta, the WTW GHG emissions were 49% higher than conventional petroleum diesel and 30% higher than oil-sands diesel. This is due to the significant electricity requirement for the PDD process and the vast differences in carbon intensities of the Ontario and Alberta grids. Overall, the other impact categories for the PDD process showed to be significantly lower than the petroleum and oil-sand derived diesel.

The Indus River Basin spans four countries, Pakistan, India, Afghanistan, and China. With transboundary flow of waters, a comprehensive hydrologic modeling system is needed to capture hydrologic response from headwater regions of major tributaries that significantly impact downstream areas. Rainfall from monsoonal seasons often produces devastating flooding along the Indus River and major tributaries. Synoptic events during winter months deposit snow in the mountainous regions of the Upper Indus River Basin which, during the spring and early summer snowmelt season, coupled with glacial melt, fills reservoirs for water resources purposes. The lack of a comprehensive and robust transboundary hydrologic modeling system complicates flood prediction and warning on the Indus River and its major tributaries. Inadequate hydrologic modeling also presents a major impediment to water resources management, principally for irrigation of croplands and hydropower generation in Pakistan, at monthly, seasonal, annual, and climate time scales. Recent surveys of hydrometeorological monitoring, data transmission, and data archiving in Pakistan find the need for considerable infrastructure modernization and capacity building. These improvements must include greatly improved data analysis, modeling, and training of professional and technical staff at all levels.

The literature is rich with interesting process design concepts, innovative ideas, and diverse approaches to designing energy systems within a sustainability mindset. However, there is no standard way of performing “eco-techno-economic” analyses in such a way that the results of different studies can be directly compared against each other in a meaningful way without significant effort. This makes it difficult to decide which process concepts are the best choices for further research, development, and investment. Therefore, I propose the development of a standardized methodology for eco-techno-economic analyses that would include a standard collection of metrics and associated computation methodologies; standard sizes, geographic locations, and applications of energy systems; standard “status-quo” baselines for comparison purposes; standard supply chains with which to conduct life cycle analyses; and open-access to computer models and data. These standards would be developed over time by an international committee of process systems engineering researchers and practitioners, interface with existing standards such as CAPE-OPEN and life cycle analysis standards, and ultimately lead to a new and continually maintained international standard. All future research studies which adhere to such standards would then be significantly more impactful since they could be directly and immediately validated, compared, adopted, reused, augmented, and understood in the larger research context.

Thermochemical conversion of solid wastes through gasification offers the dual benefit of production of high-value fuels from the recovered energy and environmentally friendly waste disposal. Waste tires in particular may be a suitable feedstock for gasification as a result of their high energy content (LHV of ~ 34 MJ/kg, higher than coal), high volatile matter, and low ash content. Rotary kilns for steam gasification are a promising and technologically mature option to handle such difficult solid wastes that have a wider range of compositions, particle sizes, and moisture contents. In this paper, we propose a novel process for production of liquefied synthetic natural gas (SNG) and electricity from waste tires through the syngas route. We use experimental data available in the open literature to represent the complex steam gasification unit operation and use modeling and simulation techniques for the other units to evaluate the technological feasibility and thermodynamic performance of the proposed process. The process has an energy efficiency of 57.1%LHV and as such shows promise as an alternative for recovery of energy and material from waste. However, further technoeconomic and life cycle analyses are required prior to process optimization in order to improve performance.

The incorporation of renewable energy sources to the market has brought a new golden era for process synthesis along with new challenges and opportunities. In this work, we give a brief review of the state of the art and then present challenges and future directions in this exciting area. The biggest driver is the rapid improvement in computer technology which greatly increases the number of factors that can be considered during the design process. Thus, some of the key future directions lie in integrating the design process with other aspects of process systems engineering, such as scheduling, planning, control, and supply chain management. In addition, sustainability is now a major consideration in which the design process must consider not only economic sustainability, but social sustainability and environmental sustainability when making design decisions. The tools available to address these challenges are limited but we are in a position to develop them based on strong chemical engineering principles following a multidisciplinary approach with contributions from other disciplines such as biology and biochemistry, computer science, materials, and chemistry.

In this paper, a novel process is proposed which converts coke oven gas (COG) and blast furnace gas (BFG) from steel refineries into methanol. Specifically, we propose to use blast furnace gases (BFG) as a carbon source, which is a fuel with a low heating value that contains CO2 and other gases. CO2 is stripped from the BFG and blended with H2-rich COG to adjust the (H2 - CO2)/(CO + CO2) molar ratio for methanol conversion. We also propose an advanced desulphurization process to remove certain sulphur compounds from the COG which can poison the methanol synthesis catalysts. The process design and simulation results using Aspen Plus are reported and used in a feasibility analysis to determine the potential environmental and energy benefits.

In this study, a new Biomass-Gas-Nuclear heat-To-Liquid fuel (BGNTL) process is presented which uses high-temperature nuclear heat as the heat source for steam methane reforming (SMR). This process co-produces liquid fuels (Fischer-Tropsch liquids, methanol and DME) and power. The BGNTL process was simulated using a combination of different software packages including gPROMS, MATLAB, ProMax, and Aspen Plus. This included the use of a rigorous multi-scale model for the nuclear-heat-powered SMR reactor which was developed in a prior work in gPROMS. Energy efficiency and cradle-to-grave life cycle inventory and life-cycle impact analyses of greenhouse gas (GHG) emissions were accomplished to analyze the environmental impacts of the BGNTL system. Plant performance was compared with a base case Biomass-Gas-To-Liquid (BGTL) process at the same size. In both processes, a carbon capture and storage (CCS) option is considered. It has been found that both processes result in negative total life cycle GHG emissions due to the use of biomass as one of the feedstocks and CCS. Furthermore, the results of this study demonstrate that BGNTL process has 5% lower direct GHG emissions and 13% lower life cycle GHG emissions compared to the BGTL process due to the nuclear heat integration. Also, by using nuclear heat, fossil fuel consumption decreased by up to 10%.

In this study, a dynamic and two-dimensional model for a steam methane reforming process integrated with nuclear heat production is developed. The model is based on first principles and considers the conservation of mass, momentum and energy within the system. The model is multi-scale, considering both bulk gas effects as well as spatial differences within the catalyst particles. Very few model parameters need to be fit based on the design specifications reported in the literature. The resulting model fits the reported design conditions of two separate pilot-scale studies (ranging from 0.4 to 10 MW heat transfer duty). A sensitivity analysis indicated that disturbances in the helium feed conditions significantly affect the system, but the overall system performance only changes slightly even for the large changes in the value of the most uncertain parameters. Ontario Ministry of Innovation via Early Researcher Award ER13-09-213

Semicontinuous distillation is a process intensification technique for purification of multicomponent mixtures. The system is control-driven and thus the control structure and its tuning parameters have crucial importance in the operation and the economics of the process. In this study, for the first time, a model predictive control (MPC) formulation is implemented on a semicontinuous process to evaluate the associated closed-loop cost. A cascade configuration of MPC and PI controllers is designed in which the setpoints of the PI controllers are determined via a shrinking-horizon MPC. The objective is to reduce the operating cost of a cycle while simultaneously maintaining the required product qualities. A subspace identification method is adopted to identify a linear, state-space model to be used in the MPC. The first-principals model of the process is then simulated in gPROMS. Simulation results demonstrate that the MPC has reduced the operational cost of a semicontinuous process by about 11%. Ontario Trillium Scholarships

In this work, a first of its kind assessment of butanol production from macroalgae through a thermochemical route is carried out. Different process configurations were designed and simulated in Aspen Plus to quantify their mass and energy balances. Furthermore, economic and environmental metrics such as the minimum butanol selling price (MBSP), and cost of CO2 equivalent emissions (CO2e) avoided were used to assess the potential of the different configurations under different market scenarios, with comparisons carried out amongst the configurations as well as against standard literature references of similar processes. Finally, a sensitivity analysis was used to assess the impact that changes in key parameters have on the considered metrics. The results show that configurations which import natural gas and electricity as utility sources alongside the macroalgae feedstock offer the lowest MBSP, however they do poorly when cost of CO2e avoided is considered. On the other hand, the configurations which utilize only macroalgae offer the best potential for cost of CO2e avoided but have the poorest values for MBSP. Inaddition, the cost of CO2e avoided obtained for the best configurations are in line with literature references. However, the MBSP values are higher than literature references for butanol derived from cellulosic feedstock primarily due to the high ash content in seaweed. The sensitivity analyses results show that changes in gasoline prices have a very significant effect on the plant configurations in the South Korean market, but not as significantly in the United States market. Ontario Research Fund – Research Excellence Grant (ORF RE-05-072)

The use of natural gas for power generation is becoming increasingly important in many regions in the world. Given that the combined cycle gas turbine (CCGT) power stations are lower in capital cost and carbon intensity than their coal-fired counterparts, natural gas fired power stations are considered a vital part of the transition to a low carbon economy. However, CCGTs are not themselves “low carbon” and in order to reach a carbon intensity of less than 50 kg CO 2 /MWh, it will be necessary to decarbonise them via CCS, with post-combustion CCS currently regarded as being a promising technology for this application. In this study, we present a detailed model of a 420 MW triple-pressure reheat CCGT and evaluate its technical and economic performance under full and part load conditions. We evaluate the technical performance of our CCGT model by comparison to an equivalent model implemented in Thermoflow THERMOFLEX and observe agreement of power output and efficiency to within 4.1% and the temperature profile within the HRSG within 2.9%. We further integrate the CCGT with a dynamic model of an amine based CCS process, and observe a reduction in the base plant efficiency from 51.84% at full-load and 50.23% at 60% load by 8.64% points at full-load and 7.93% points at 60% load. A core conclusion of this paper is that CCGT power plants equipped with post-combustion CCS technologies are well suited to dynamic operation, as might be required in an energy system characterised by high penetrations of intermittent renewable power generation.

In this work, a two-stage rolling horizon optimization (RHO) framework is formulated and applied to a SOFC/CAES integrated power plant to achieve optimal year-round peaking power with zero emissions. The two-stage RHO exploits the modular nature of the upstream SOFC power island to make safe and reliable changes to the plant’s nominal operating point to follow seasonal demand trends in the first stage, and uses the CAES system to match hourly fluctuations in demand. Results for a simulated year using historical demand data show that the two-stage RHO improves load-following by as much as 90% as measured by the integrated squared error between supply and demand.

This work compares various chemicals for use as extractants in second-generation Acetone-Butanol-Ethanol fermentation on economic and environmental bases. Both non-toxic and toxic extractants are considered in this study. The combinative extractive-distillation separation process was modelled using a combination of Microsoft Excel 2013, MATLAB 2015 and Aspen Plus v8.8. Separation trains were designed and optimized for each extractant to best take advantage of extractant properties. Upstream units considered in this analysis include: biomass (switchgrass) solids processing, biomass pre-treatment and saccharification, and fermentation. Downstream processes considered include utility generation and wastewater treatment. The cost of CO2 equivalent emissions avoided (CCA) was used as the metric to compare the environmental impact of each process as compared to conventional petroleum-based gasoline. The economic and environmental best extractant is shown to be 2-ethyl-hexanol with a minimum butanol selling price of $1.58/L and a CCA of $471.57/tonne CO2 equivalent emissions avoided. The authors acknowledge financial support from an Ontario Research Fund—Research Excellent Grant (ORF-RE-05-072), an Ontario Graduate Scholarship, and an Ashabaugh Graduate Scholarship.

Semicontinuous separation is a distillation based process intensification technique devised for the purification of ternary mixtures to desired purities. It is particularly promising for small scale production processes where the semicontinuous system has a lower total annualized cost relative to the conventional continuous process, thus it can be a suitable option for the purification of biofuels. Semicontinuous systems are dynamic, control driven processes that work in a stable limit cycle with several modes of operations. Therefore, designing the system and its controllers is a challenging task which has not been thoroughly considered in the literature. In this work, for the first time, a methodology is presented to simultaneously obtain the optimum design parameters of the semicontinuous system such as the number of column stages, feed and side stream locations, as well as the optimum tuning parameters for the PI control structure. To design the semicontinuous process, it is formulated as a mixed integer nonlinear dynamic optimization problem using the equation oriented gPROMS software which has built-in deterministic optimization packages. The benzene, toluene and o-xylene mixture is chosen as a case study to demonstrate the methodology. The optimization took 1.03 CPU hours and the optimum design parameters are obtained. The results show that the total annualized cost of the designed semicontinuous system is lower than the respective conventional continuous process.

The solid oxide fuel cell gas turbine hybrid system (SOFC/GT) is an exciting new approach to producing electricity with high efficiency and lower environmental impacts than conventional power plants. One of its key strengths is the potential for fuel flexibility, which is the ability to transition between different kinds or qualities of fuels during operation. However, there has been very little research into the dynamic performance of SOFC/GT systems in response to changes in fuel. Therefore, the open loop behaviour of SOFC/GT systems in response to fuel composition transients was experimentally investigated. In this study, hardware-based simulations were used to study transitions between using coal-derived syngas and humidified methane. A hybrid test facility at the U.S Department of Energy, National Energy Technology Laboratory, Morgantown, West Virginia, was used to adequately capture the coupling of fuel cell stacks (simulated with hardware driven by a real time dynamic model) and a gas turbine system (from actual equipment) during transient events. Given the dynamic trajectories of key process variables, the impact on the hybrid system was quantified via transfer functions. The results show that the open-loop dynamic behaviour exhibited significant inverse response which limited the range of transitions that could be achieved safely without damage to various system components such as the compressor or fuel cells. However, the results also showed that if a control system could be designed which limited the impact of the inverse response, then transitions between even very different kinds of fuels could potentially be achieved without operational problems. The resulting transient information will be used to develop a new control system for thermal management of SOFC/GT hybrid systems in future work.

In this perspective, an overview of the key challenges and opportunities in the design of new energy systems is presented. Recent shifts in the prices of natural energy resources combined with growing environmental concerns are creating a new set of challenges for process design engineers. Due to the massive scale and impact of energy conversion processes, some of the best solutions to the energy crisis lie in the design of new process systems which address these new problems. In particular, many of the most promising solutions take a big-picture approach by integrating many different processes together to take advantage of synergies between seemingly unrelated processes.

Biobutanol production through the thermochemical route allows the use of a wide variety of feedstocks (including lignocellulosic biomass) and is a potentially superior alternative to the biochemical route. However the thermochemical route is poorly understood and no techno-economic studies of the thermochemical route exist in the peer-reviewed literature to our knowledge. To address this issue, this work focuses on the use of CAPE tools in modelling a novel thermochemical lignocellulosic biomass-to-butanol process and an assessment of its economic feasibility. This goal is achieved with a three-step methodology comprising of process simulation, heat integration, and an economic analysis. The application of this methodology results in a minimum butanol selling price (MBSP) which is competitive with biobutanol via the biochemical route. A sensitivity analysis on different design and cost parameters confirm that this process is quite promising under a large range of uncertain market conditions.

This chapter provides a detailed methodology for constructing steady-state flow sheet simulations of common solvent-based CO2 and H2S capture processes using popular commercial software. Detailed examples are provided for solvents such as monoethanolamine, methyldiethanolamine, DGA, Piperazine, Selexol, and Rectisol in a variety of applications, such as integrated gasification combined cycles, gas-to-liquid plants, coal-to-liquid plants, natural gas combined cycles, and sweet and sour gas cleaning. Tutorials are provided for Aspen Plus, Aspen Hysys, BRE ProMax, and Invensys Pro/II, with screen captures, step-by-step guides, and expert advice designed to make the construction of these notoriously difficult simulations as easy as possible. Twenty-one different examples are discussed, with completed simulation files available for download for the reader.

In this work, a new shale gas-based polygeneration system with essentially zero CO2 emissions is proposed that co-produces methanol, dimethyl ether (DME), olefins and power. The thermal and economic analysis of the proposed process is performed to determine the optimum product portfolio regarding current market prices. The optimization results show that production of methanol/DME and power can improve the performance of the olefin production section significantly. Therefore, the proposed plant can link the shale gas industry to the petrochemical sector efficiently and in an environmentally friendly way.

In this work, the economic and environmental impact of integrating nuclear energy into a coal-and-gas-to-liquids process has been investigated. Reductions in CO2 emissions are possible because certain synergies can be exploited when coal, natural gas, and nuclear heat are used in combination, giving efficiency advantages which are unavailable when only a single energy source is used. Sixteen different design configurations are considered in this study, reflecting different design choices such as how to use or recycle light waste gases from the Fischer-Tropsch section, whether or not to integrate nuclear energy into the system, and also whether or not to include CO2 capture. Compared to a “traditional” coal-and-gas-to-liquids process, the results show that in some configurations CO2 emitted by the process can be reduced by over 99% with the use of nuclear heat by using the optional carbon capture and sequestration (CCS) option. However, even without CCS, the use of nuclear heat as a contributing energy source can reduce the CO2 emissions per gallon of gasoline and diesel produced by 17-42% from the equivalent non-nuclear-heat case. Total fossil fuel use can also be reduced by 12-21% (by higher heating value) per gallon produced.

An environmentally friendly electricity generation process using coal gasification and solid oxide fuel cells (SOFCs) produces electricity with high efficiency, 99.95% carbon capture and essentially zero atmospheric emissions. Coal is gasified into syngas, cleaned and shifted to hydrogen gas to fuel SOFCs. The primary waste products, CO2 and H2O, are separated with a very small energy penalty. The carbon dioxide purity is high enough to meet most specifications for geological sequestration. Even with carbon capture capability, the power plant has a higher efficiency (4-10 percentage points) than standard pulverized coal or integrated gasification combined cycle processes without carbon capture and consumes significantly less fresh water. If cooling towers are replaced with dry-cooling technology, net water can be produced and recovered, rather than consumed. Moreover, under a cap-and-trade scenario, the process has the lowest cost-of-electricity, even with carbon capture, for carbon prices above $5-10/tonne.

Semicontinuous reactive distillation (SRD) is a novel processing technique that tightly integrates reactions and separations together using forced cyclic principles. Previous simulations of SRD have shown that it is not only feasible, but also economically superior to equivalent batch and continuous processes for a wide range of production rates. Although the SRD process is complex, the suggested synthesis algorithm provides a method for generating an SRD schema from continuous or batch designs.