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Capital Costs (capital + cost)
Selected AbstractsEnergy optimization for the design of corn-based ethanol plantsAICHE JOURNAL, Issue 6 2008Ramkumar Karuppiah Abstract In this work, we address the problem of optimizing corn-based bioethanol plants through the use of heat integration and mathematical programming techniques. The goal is to reduce the operating costs of the plant. Capital cost, energy usage, and yields,all contribute to production cost. Yield and energy usage also influence the viability of corn-based ethanol as a sustainable fuel. We first propose a limited superstructure of alternative designs including the various process units and utility streams involved in ethanol production. Our objective is to determine the connections in the network and the flow in each stream in the network such that we minimize the energy requirement of the overall plant. This is accomplished through the formulation of a mixed-integer nonlinear programming problem involving short-cut models for mass and energy balances for all the units in the system, where the model is solved through two nonlinear programming subproblems. We then perform a heat integration study on the resulting flowsheet; the modified flowsheet includes multieffect distillation columns that further reduces energy consumption. The results indicate that it is possible to reduce the current steam consumption required in the transformation of corn into fuel grade ethanol by more than 40% compared to initial basic design. © 2008 American Institute of Chemical Engineers AIChE J, 2008 [source] An Evaluation of Physicochemical Treatment Technologies for Water Contaminated with MTBEGROUND WATER MONITORING & REMEDIATION, Issue 4 2000Arturo A. Keller Treatment of methyl tertiary-butyl ether (MTBE) from contaminated surface and ground water supplies presents specific challenges due to the physicochemical properties of MTBE that depend strongly on its hydrophilic nature, and translate into a high solubility in water, and low Henry's constant and low affinity for common adsorbents. We evaluate four treatment technologies-air stripping, granular activated carbon (GAC), hydrophobic hollow fiber membranes, and advanced oxidation processes (AOP)-using ozone or ozone/hydrogen peroxide. Experimental work was carried out to generate parameter values necessary for the design of these processes. Ten different flow rates/concentration combinations were evaluated in our designs to cover the range from high flow rate/low concentration typical of surface water and ground water drinking water supplies to low flow rate/high concentration typical of ground water remediation sites. For all cases, the processes were designed to produce effluent water of 5 ,g/L or less. Capital costs and operation and maintenance costs were determined at the feasibility level by using standard engineering estimating practices. Air stripping is the lowest cost technology for high flow rales (100 to 1000 gpm) if no air treatment is required. Hollow fiber membranes are the lowest cost technology for flow rates of 10 to 100 gpm if no air treatment is required, which is typical at these low flow rates. GAC will be most costeffective at all flow rates if air treatment is required and the influent water has low levels of other organic compounds. AOP using ozone or ozone/hydrogen peroxide is in all cases more expensive than the alternative technologies, and there are sufficient uncertainties at this point with respect to byproducts of AOP to warrant further study of this technology. The cost of treating MTBE-contaminated water for conventional technologies such as air stripping and GAC is 40% to 80% higher than treating water contaminated only with other hydrocarbons such as benzene. [source] Thermoeconomic optimization of the geometry of an air conditioning precooling air reheater dehumidifierINTERNATIONAL JOURNAL OF ENERGY RESEARCH, Issue 4 2006Rahim K. Jassim Abstract Exergy method of optimization for the geometrical parameters of an air conditioning precooling air reheater with turbulent flow is developed in this paper. The method is based on exergy, economic analysis and optimization theory. As there are humid air streams involved in the heat transfer process, then there are irreversibilities or exergy destruction, which is due to pressure losses, temperature difference and specific humidity gradient. These principle components of total irreversibility are not independent and there is a trade-off between them. Therefore, the purpose of this research paper is to study the effect of the geometry and the specific humidity of the two streams on the irreversibilities of a crossflow precooling air reheater dehumidifier. Also, the optimum balance between the three components of irreversibility is determined thereby giving the optimum solution for heat exchanger area. The total cost function is expressed on an annualized basis of the sum of the precooler capital cost and the running cost attributable to the precooler irreversibility. This total cost function is optimized in this paper according to the optimum heat transfer area and the total irreversibilities. Two optimum heat transfer areas were found for minimum total irreversibility and minimum total annual cost for a specific example. Finally, the relations between the typical operational variables such as heat transfer area, Reynolds numbers and the total annual cost for the precooler is developed and presented in graphs, which allow the calculation of the optimal heat transfer area, which gives the optimum irreversibility and minimum total annual cost. Copyright © 2005 John Wiley & Sons, Ltd. [source] Conjunctive water management options: examples from economic assessment of system-level water saving through Liuyuankou Irrigation System, China,IRRIGATION AND DRAINAGE, Issue 5 2007Shahbaz Khan économies d'eau à l'échelle d'un périmètre; modèle dynamique d'un système d'irrigation; fonctions de production et de profit; Chine Abstract The paper provides results of a study aimed at saving a substantial amount of water by maintaining deeper groundwater levels to prevent fallow evaporation and by reducing the cost of groundwater abstraction for lowland farmers. An integrated LIS economic appraisal model was developed that linked simulated response of hydrological modelling of different conjunctive management options with economic analysis. The simulation results of the LIS system dynamic model show that a combination of canal lining and pumping groundwater is the most cost-effective way to reduce non-beneficial evapotranspiration and increase water availability by saving up to 68 MCM of water. The simulation results of economic parameters indicated that canal lining and pumping also offer highest net economic benefits (¥21.98 million). Among other options, canal lining also indicates reasonably high net economic benefits (¥9.02 million). The model indicates a small increase in marginal value of water with canal lining (¥1.53,m,3) and pumping and canal lining (¥1.62,m,3). Among other options, the marginal capital cost of water saving for pumping and canal lining together was the lowest (¥0.096,m,3). However, the marginal capital cost of water saving for pumping and shifting canal water downstream was the most expensive (¥1.046,m,3). Copyright © 2007 John Wiley & Sons, Ltd. L'article présente les résultats d'une étude destinée à économiser des quantités d'eau substantielles en maintenant le niveau des nappes suffisamment bas pour éviter l'évaporation non bénéficiaire et en réduisant le coût des prélèvements d'eau souterraine pour les irrigants des parties basses du périmètre. Le modèle d'évaluation économique intégrée LIS (Liuyuankou Irrigation System) a été développé en reliant les réponses simulées de modélisation hydrologique de différentes options de gestion mixte à l'analyse économique. Les résultats des simulations du modèle LIS montrent que la combinaison du revêtement des canaux et du pompage d'eau souterraine est le moyen le plus efficient de réduire l'évapotranspiration non bénéficiaire et d'augmenter la disponibilité de l'eau en économisant jusqu'à 68 Mm3. Les simulations économiques indiquent que le revêtement des canaux et le pompage procurent les bénéfices économiques nets les plus élevés (21,98 millions de ¥). Parmi les autres options, le revêtement des canaux seul procure lui aussi des bénéfices économiques nets relativement élevés (9,02 millions de ¥). Le modèle indique une légère augmentation de l'utilité marginale de l'eau en cas de canaux revêtus (1,53 ¥ m,3) et en cas de combinaison revêtement + pompage (1,62 ¥ m,3). Parmi les autres options, le coût marginal d'économie de l'eau pour la même combinaison était le plus bas (0,096 ¥ m,3). Cependant, le coût marginal d'économie d'eau pour pompage et transfert vers l'aval était le plus coûteux (1,046 ¥ m,3). Copyright © 2007 John Wiley & Sons, Ltd. [source] Automation of paratransit reservation, routing, and schedulingJOURNAL OF ADVANCED TRANSPORTATION, Issue 2 2000T. Chira-Chavala Santa Clara County, California experienced a sharp growth in demand-responsive paratransit ridership for individuals with disabilities, as a result of the passage of the 1990 Americans With Disabilities Act (ADA). This paper describes an automated paratransit system for the ADA-type paratransit operation implemented in Santa Clara County. It automated paratransit reservation, scheduling, and routing functions. The key components of this system were a digital geographic database (DGD) and an automated trip scheduling system (ATSS). Empirical evidence after one year of operation indicates numerous benefits of this automation. There were significant reductions in the paratransit operating costs and an increase in the percent shared rides. The savings in operating costs far exceeded the annualized capital cost of automation. A user survey indicates that these improvements were achieved without degradation to service quality such as vehicle on-time performance, invehicle travel times, vehicle response to open return, and ride comfort. [source] A review of pervaporation for product recovery from biomass fermentation processes,JOURNAL OF CHEMICAL TECHNOLOGY & BIOTECHNOLOGY, Issue 6 2005Leland M Vane Abstract Although several separation technologies are technically capable of removing volatile products from fermentation broths, distillation remains the dominant technology. This is especially true for the recovery of biofuels such as ethanol. In this paper, the status of an emerging membrane-based technology, called pervaporation, for this application is reviewed. Several issues and research priorities which will impact the ability of pervaporation to be competitive for biofuel recovery from fermentation systems are identified and discussed. They include: increased energy efficiency; reduction of capital cost for pervaporation systems; longer term trials with actual fermentation broths; optimized integration of pervaporation with fermentor; synergy of performing both alcohol recovery and solvent dehydration by pervaporation with dephlegmation fractional condensation technology; and updated economic analyses of pervaporation at various biofuel production scales. Pervaporation is currently viable for biofuel recovery in a number of situations, but more widespread application will be possible when progress has been made on these issues. Published in 2005 for SCI by John Wiley & Sons, Ltd. [source] Internal heat integration , the key to an energy-conserving distillation column,JOURNAL OF CHEMICAL TECHNOLOGY & BIOTECHNOLOGY, Issue 2-3 2003Z Olujic Abstract This paper illustrates the thermal energy conservation potential of the so-called heat integrated distillation column (HIDiC), which combines advantages of direct vapour recompression and diabatic operation at half of the normal column height. In a typical close boiling mixture separation, compared with a column utilising the usual vapour recompression scheme, HIDiC halved the consumption of exergy at approximately the same capital cost, indicating a strikingly short pay-off time. The complexities of integrating the heat transfer equipment in the stripping section with proven gas/liquid contacting devices, which may work adversely to practical implementation of HIDiC concept, are also addressed. © 2003 Society of Chemical Industry [source] Cost analysis of proton exchange membrane fuel cell systemsAICHE JOURNAL, Issue 7 2008Ai-Jen Hung Abstract Tradeoff between capital cost and the operating cost can be seen in the design of proton exchange membrane fuel cell systems. The polarization curve indicates that operating in the region of lower current densities implies less operating cost (hydrogen fuel) and higher capital cost (larger membrane electrode assembly area). The opposite effects are observed when one operates in the region of higher current densities. Therefore, an appropriate design should take both factors into account and the optimality depends on the corresponding costs of hydrogen and membrane area. An analytical cost model is constructed to describe such an economic balance in a proton exchange membrane fuel cell system. The objective function of the optimization is the total annual cost. Six scenarios are used to illustrate the optimal design based on the total annual cost as cost and materials factors fluctuate. © 2008 American Institute of Chemical Engineers AIChE J, 2008 [source] On the theory of optimal sensor placementAICHE JOURNAL, Issue 5 2002Donald J. Chmielewski On the Theory of Optimal Sensor Placement An optimal sensor placement is defined as a sensor configuration that achieves the minimum capital cost while observing prespecified performance criteria. Previous formulations of this problem have resulted in the definition of a mixed-integer nonlinear program (MINLP) with dimensions dependent on the value of the integer decision variables. The main contribution of this work is an equivalent reformulation of the design problem such that the dimension of the NLP is independent of all decision variables. Additionally, the traditional sensor-placement problem, based on static process conditions, is extended to linear dynamic processes. The final contribution is the exact conversion of the general NLP into a convex program through the use of linear matrix inequalities. The aggregation of these results show that the sensor-placement problem can be solved globally and eficiently using standard interior-point and branch-and-bound search algorithms. [source] Capital Equalization and the Australian StatesTHE ECONOMIC RECORD, Issue 232 2000JEFFREY PETCHEY The Australian Grants Commission has recently considered ways to take account of differences in capital costs across States within the existing fiscal equalization formula. Here we develop a theoretical methodology for estimating differences in the costs of capital faced by the States in the General Government Sector. This methodology is used to generate preliminary estimates of State capital cost ,disabilities' from 1962,63 to 1995,96. Finally, we suggest how the methodology and the estimates of capital cost disabilities might be integrated into the Commission's formula to produce a grant distribution which reflects different costs of capital across States. [source] Employer burden of mild, moderate, and severe major depressive disorder: mental health services utilization and costs, and work performance,DEPRESSION AND ANXIETY, Issue 1 2010Howard G. Birnbaum Ph.D. Abstract Background: Treatment utilization/costs and work performance for persons with major depressive disorder (MDD) by severity of illness is not well documented. Methods: Using National Comorbidity Survey-Replication (2001,2002) data, US workforce respondents (n=4,465) were classified by clinical severity (not clinically depressed, mild, moderate, severe) using a standard self-rating scale [Quick Inventory of Depressive Symptomatology Self-Report (QIDS-SR)]. Outcomes included 12-month prevalence of medical services/medications use/costs and workplace performance. Treatment costs (employer's perspective) were estimated by weighing utilization measures by unit costs obtained for similar services used by MDD patients in claims data. Descriptive analysis across three severity groups generated ,2 results. Results: Using a sample of 539 US workforce respondents with MDD, 13.8% were classified mild, 38.5% moderate, and 47.7% severe cases. Mental health services usage, including antidepressants, increased significantly with severity, with average treatment costs substantially higher for severe than for mild cases both regarding mental health services ($697 vs. $388, ,2=4.4, P=.019) and antidepressants ($256 vs. $88, ,2=9.0, P=.001). Prevalence rates of unemployment/disability increased significantly (,2=11.7, P=.003) with MDD severity (15.7, 23.3, and 31.3% for mild, moderate, and severe cases). Severely and moderately depressed workers missed more work than nondepressed workers; the monthly salary-equivalent lost performance of $199 (severely depressed) and $188 (moderately depressed) was significantly higher than for nondepressed workers (,2=10.3, P<.001). Projected to the US workforce, monthly depression-related worker productivity losses had human capital costs of nearly $2 billion. Conclusions: MDD severity is significantly associated with increased treatment usage/costs, treatment adequacy, unemployment, and disability and with reduced work performance. Depression and Anxiety, 2010. © 2009 Wiley-Liss, Inc. [source] Simulation of the market penetration of hydrogen fuel cell vehicles in KoreaINTERNATIONAL JOURNAL OF ENERGY RESEARCH, Issue 4 2008Eunju Jun Abstract As fuel cell technologies are developed, hydrogen-powered vehicles are receiving more interest. The hydrogen economy, particularly hydrogen-powered vehicle penetration into the Korean transportation market, is studied in this paper. Vensim, a system dynamic code, was used to simulate the dynamics in the transportation market, assuming various types of vehicles such as gasoline, hybrid electricity, and hydrogen powered. Market share for each vehicle was predicted using the currently available data. The results showed that the hydrogen era will not be as bright as predicted by many people. The main barrier is the fuel cell cost. Thus, in order to expand the fuel cell vehicles (FCVs) market, hydrogen fuel cell cost needs to be dramatically reduced. Hydrogen-powered FCV cost, including operating and capital costs, should reach $0.16 per kilometer in order to seize 50% of the newly created transportation market. However, if strong policies or subsidies are implemented, the results predicted here will be affected. Copyright © 2007 John Wiley & Sons, Ltd. [source] Process integration technology review: background and applications in the chemical process industryJOURNAL OF CHEMICAL TECHNOLOGY & BIOTECHNOLOGY, Issue 9 2003Russell F Dunn Abstract Process integration is a holistic approach to process design and operation which emphasizes the unity of the process. Process integration design tools have been developed over the past two decades to achieve process improvement, productivity enhancement, conservation in mass and energy resources, and reductions in the operating and capital costs of chemical processes. The primary applications of these integrated tools have focused on resource conservation, pollution prevention and energy management. Specifically, the past two decades have seen the development and/or application of process integration design tools for heat exchange networks (HENs), wastewater reduction and water conservation networks, mass exchange networks (MENs), heat- and energy-induced separation networks (HISENs and EISENs), waste interception networks (WINs) and heat- and energy-induced waste minimization networks (HIWAMINs and EIWAMINs), to name a few. This paper provides an overview of some of these developments and outlines major driving forces and hurdles. The fundamental aspects of this approach along with their incorporation in an overall design methodology will be discussed. The paper also highlights several recent applications of process integration to industrial processes. Copyright © 2003 Society of Chemical Industry [source] Synthesis of mechanical driver and power generation configurations, Part 1: Optimization frameworkAICHE JOURNAL, Issue 9 2010Frank L. Del Nogal Abstract This article presents a novel, systematic, and robust procedure for driver and power plant selection based on mathematical programming. The discrete nature of gas turbines is considered as gas turbine drivers and gas turbine-based power plants are selected from a group of candidates. Plant availability with considering parallel compression has also been included, which allows a more comprehensive exploitation of the trade-offs between capital costs, operating costs, and availability. When neglecting process heating and any steam equipment, the formulation can be applied to heavily power dominated processes, such as LNG. However, a more comprehensive formulation, allowing waste heat recovery and the integration with a multilevel steam system, is also proposed to produce more thermally efficient systems. This approach proved to be flexible and robust and is the first in producing solutions ranging from no-steam to all-steam systems, including all-gas turbine, all-motor and hybrid gas turbine/motor/steam systems. © 2010 American Institute of Chemical Engineers AIChE J, 2010 [source] ECONOMIC FUNDAMENTALS IN LOCAL HOUSING MARKETS: EVIDENCE FROM U.S. METROPOLITAN REGIONSJOURNAL OF REGIONAL SCIENCE, Issue 3 2006Min Hwang ABSTRACT This paper investigates the effects of national and regional economic conditions on outcomes in the single-family housing market: housing prices, vacancies, and residential construction activity. Our three-equation model confirms the importance of changes in regional economic conditions, income, and employment on local housing markets. The results also provide the first detailed evidence on the importance of vacancies in the owner-occupied housing market on housing prices and supplier activities. The results also document the importance of variations in materials, labor and capital costs, and regulation in affecting new supply. Simulation exercises, using standard impulse response models, document the lags in market responses to exogenous shocks and the variations arising from differences in local parameters. The results also suggest the importance of local regulation in affecting the pattern of market responses to regional income shocks. [source] Economic Feasibility of Aquaculture of Spiny Lobsters Jasus edwardsii in Temperate WatersJOURNAL OF THE WORLD AQUACULTURE SOCIETY, Issue 1 2000Andrew Jeffs Around the world there is strong interest in the aquaculture of spiny lobsters (family Palinuridae). However, there is little published information about the economic feasibility of spiny lobster aquaculture. For more than 20 yr there has been experimental grow out of the spiny lobster Jasus edwardsii in New Zealand in land-based systems using seed animals (puerulus) taken from the wild. These studies provide sufficient information on growth, mortality, food conversion, handling and capital costs to enable an assessment of the economic feasibility of the commercial culture of spiny lobsters in temperate waters. This assessment suggests that profitable spiny lobster aquaculture will rely on greatly reducing the infrastructure and operating costs of land-based farming operations, as well as lowering feed and labor costs. Financial simulations suggest that increasing productivity through faster growth rates and lowered culture mortalities will only have a minor effect on profitability unless infrastructure and operating costs can be reduced significantly. Seacage culture or sea ranching of spiny lobsters may offer a means of avoiding high infrastructure costs associated with land-based farming operations. The development of a cost-effective artificial feed would also appear to be a priority for improving the economic outlook for culturing spiny lobsters. The results of this study are relevant to the economics of spiny lobster culture developments in other temperate regions of the world. [source] Exploration and development of Iran's oilfields through buybackNATURAL RESOURCES FORUM, Issue 3 2006Abdolhossein Shiravi Abstract The use of buyback for the development of oil and gas fields is an established mechanism in Iran. Current legislation authorizes the National Iranian Oil Company (NIOC) to use buyback for both exploration and development. The buyback scheme can be defined as a risk service contract, under which the contractor is paid back by being allocated a portion of oil/gas produced as a result of providing services. Buyback is based upon a defined scope of work, a capital cost ceiling, a fixed remuneration fee and a defined cost recovery period. When buyback is used for both exploration and development, the specifications of the field to be developed are unknown at the time of contracting and therefore agreement on the scope of work, duration of development operations, ceiling for capital costs, fixed remuneration fee, and duration of cost recovery need to be deferred to the time when a commercial field is discovered. This article first outlines the introduction of buyback for development of Iran's oil and gas fields. It then examines the main features of the mechanism. Third, the use of buyback for both exploration and development is explored and related challenges discussed. Finally, the article reviews the new buyback model proposed by NIOC to address these challenges. [source] The Entry Cost Shock and the Re-rating of Power Prices in New South Wales, AustraliaTHE AUSTRALIAN ECONOMIC REVIEW, Issue 2 2010Paul Simshauser Australia has long been the beneficiary of low, stable power prices. A decade-long state of oversupply underpinned this result and while plant capital costs had been rising, the cost of capital had been declining. These offsetting effects locked the wholesale market into an average cost of $35,$40/MWh. However, from 2007, a simultaneous and sharp rise in new entrant plant capital costs and the cost of capital occurred. The combined effects crept up on the industry while it was in a state of oversupply. This ,entry cost shock' disrupted a 7 year long equilibrium price, with average power system cost rising to $60/MWh. [source] Capital Equalization and the Australian StatesTHE ECONOMIC RECORD, Issue 232 2000JEFFREY PETCHEY The Australian Grants Commission has recently considered ways to take account of differences in capital costs across States within the existing fiscal equalization formula. Here we develop a theoretical methodology for estimating differences in the costs of capital faced by the States in the General Government Sector. This methodology is used to generate preliminary estimates of State capital cost ,disabilities' from 1962,63 to 1995,96. Finally, we suggest how the methodology and the estimates of capital cost disabilities might be integrated into the Commission's formula to produce a grant distribution which reflects different costs of capital across States. [source] Financial Impact of Emergency Department UltrasoundACADEMIC EMERGENCY MEDICINE, Issue 7 2009Olanrewaju A. Soremekun MD Abstract Objectives:, There is limited information on the financial implications of an emergency department ultrasound (ED US) program. The authors sought to perform a fiscal analysis of an integrated ED US program. Methods:, A retrospective review of billing data was performed for fiscal year (FY) 2007 for an urban academic ED with an ED US program. The ED had an annual census of 80,000 visits and 1,101 ED trauma activations. The ED is a core teaching site for a 4-year emergency medicine (EM) residency, has 35 faculty members, and has 24-hour availability of all radiology services including formal US. ED US is utilized as part of evaluation of all trauma activations and for ED procedures. As actual billing charges and reimbursement rates are institution-specific and proprietary information, relative value units (RVUs) and reimbursement based on the Centers for Medicare & Medicaid Services (CMS) 2007 fee schedule (adjusted for fixed diagnosis-related group [DRG] payments and bad debt) was used to determine revenue generated from ED US. To estimate potential volume, assumptions were made on improvement in documentation rate for diagnostic scans (current documentation rates based on billed volume versus diagnostic studies in diagnostic image database), with no improvements assumed for procedural ED US. Expenses consist of three components,capital costs, training costs, and ongoing operational costs,and were determined by institutional experience. Training costs were considered sunken expenses by this institution and were thus not included in the original return on investment (ROI) calculation, although for this article a second ROI calculation was done with training cost estimates included. For the purposes of analysis, certain key assumptions were made. We utilized a collection rate of 45% and hospitalization rates (used to adjust for fixed DRG payments) of 33% for all diagnostic scans, 100% for vascular access, and 10% for needle placement. An optimal documentation rate of 95% was used to estimate potential revenue. Results:, In FY 2007, 486 limited echo exams of abdomen (current procedural terminology [CPT] 76705) and 480 limited echo cardiac exams were performed (CPT 93308) while there were 78 exams for US-guided vascular access (CPT 76937) and 36 US-guided needle placements when performing paracentesis, thoracentesis, or location of abscess for drainage (CPT 76492). Applying the 2007 CMS fee schedule and above assumptions, the revenue generated was 578 RVUs and $35,541 ($12,934 in professional physician fees and $22,607 in facility fees). Assuming optimal documentation rates for diagnostic ED US scans, ED US could have generated 1,487 RVUs and $94,593 ($33,953 in professional physician fees and $60,640 in facility fees). Program expenses include an initial capital expense (estimated at $120,000 for two US machines) and ongoing operational costs ($68,640 per year to cover image quality assurance review, continuing education, and program maintenance). Based on current revenue, there would be an annual operating loss, and thus an ROI cannot be calculated. However, if potential revenue is achieved, the annual operating income will be $22,846 per year with an ROI of 4.9 years to break even with initial investment. Conclusions:, Determining an ROI is a required procedure for any business plan for establishing an ED US program. Our analysis demonstrates that an ED US program that captures charges for trauma and procedural US and achieves the potential billing volume breaks even in less than 5 years, at which point it would generate a positive margin. [source] Performance and cost analysis of future, commercially mature gasification-based electric power generation from switchgrassBIOFUELS, BIOPRODUCTS AND BIOREFINING, Issue 2 2009Haiming Jin Abstract Detailed process designs and mass/energy balances are developed using a consistent modeling framework and input parameter assumptions for biomass-based power generation at large scale (4536 dry metric tonnes per day switchgrass input), assuming future commercially mature component equipment performance levels. The simulated systems include two gasification-based gas turbine combined cycles (B-IGCC) designed around different gasifier technologies, one gasification-based solid oxide fuel cell cycle (B-IGSOFC), and a steam-Rankine cycle. The simulated design-point efficiency of the B-IGSOFC is the highest among all systems (51.8%, LHV basis), with modestly lower efficiencies for the B-IGCC design using a pressurized, oxygen-blown gasifier (49.5% LHV) and for the B-IGCC design using a low-pressure indirectly heated gasifier (48.6%, LHV). The steam-Rankine system has a simulated efficiency of 33.0% (LHV). Detailed capital costs are estimated assuming commercially mature (,Nth plant') technologies for the two B-IGCC and the steam-Rankine systems. B-IGCC systems are more capital-intensive than the steam-Rankine system, but discounted cash flow rate of return calculations highlight the total cost advantage of the B-IGCC systems when biomass prices are higher. Uncertainties regarding prospective mature-technology costs for solid oxide fuel cells and hot gas sulfur clean-up technologies assumed for the B-IGSOFC performance analysis make it difficult to evaluate the prospective electricity generating costs for B-IGSOFC relative to B-IGCC. The rough analysis here suggests that B-IGSOFC will not show improved economics relative to B-IGCC at the large scale considered here. © 2009 Society of Chemical Industry and John Wiley & Sons, Ltd [source] Techno-economic evaluation of a two-step biological process for hydrogen productionBIOTECHNOLOGY PROGRESS, Issue 2 2010Mattias Ljunggren Abstract An integrated biological process for the production of hydrogen based on thermophilic and photo-heterotrophic fermentation was evaluated from a technical and economic standpoint. Besides the two fermentation steps the process also includes pretreatment of the raw material (potato steam peels) and purification of hydrogen using amine absorption. The study aimed neither at determining the absolute cost of biohydrogen nor at an economic optimization of the production process, but rather at studying the effects of different parameters on the production costs of biohydrogen as a guideline for future improvements. The effect of the key parameters, hydrogen productivity and yield and substrate concentration in the two fermentations on the cost of the hydrogen produced was studied. The selection of the process conditions was based mainly on laboratory data. The process was simulated by use of the software Aspen Plus and the capital costs were estimated using the program Aspen Icarus Process Evaluator. The study shows that the photo-fermentation is the main contributor to the hydrogen production cost mainly because of the cost of plastic tubing, for the photo-fermentors, which represents 40.5% of the hydrogen production cost. The costs of the capital investment and chemicals were also notable contributors to the hydrogen production cost. Major economic improvements could be achieved by increasing the productivity of the two fermentation steps on a medium-term to long-term scale. © 2009 American Institute of Chemical Engineers Biotechnol. Prog., 2010 [source] | |||||||||||||||||||||||||