Equipment Purchase Costs Research Articles

Design and optimization of power hubs for Brazilian off-shore oil production units

A worldwide trend to reduce greenhouse gases emissions has encouraged researchers to study more efficient solutions in oil and gas Industry. Most offshore units are energized by equipment operating at low loads, increasing environmental impact. This work aims identifying optimal designs and layouts of a combined cycle floating power hub tailored for offshore oil production applications. The Brazilian pre-salt basin which forecast high fuel gas production is taken as a case study. A model was developed, integrating the design of the gas turbine, heat recovery units, steam turbine and condenser. Genetic algorithms were applied in two optimization approaches, single-objective and multi-objective. Three parameters were evaluated: equipment purchase cost, thermal efficiency and total weight. The results of the multi-objective optimization indicated that dual-pressure arrangements, featuring 3 gas turbines, 1 heat recovery steam generator and 1 steam cycle, could be an attractive design solution for power hubs. This arrangement has a low cost and weight, while the thermal efficiency is maintained at a reasonably high level (around 53.2%). Moreover, results indicated that CO2 emissions may be reduced by 18.7%–27.2% at design point and 19% for the power hub lifetime, when compared with the conventional energy supply scenario.

Exergy and Economic Evaluation of a Hybrid Power Plant Coupling Coal with Solar Energy

Hybrid power plants that couple conventional with renewable energy are promising alternatives to electricity generation with low greenhouse gas emissions. Such plants aim to improve the operational stability of renewable power plants, while at the same time reducing the fuel consumption of conventional fossil fuel power plants. Here, we propose and evaluate the thermodynamic and economic viability of a hybrid plant under different operating conditions, applying exergy and economic analyses. The hybrid plant combines a coal plant with a solar-tower field. The plant is also compared with a conventional coal-fired plant of similar capacity. The results show that the proposed hybrid plant can emit 4.6% less pollutants due to the addition of solar energy. Fuel consumption can also be decreased by the same amount. The exergy efficiency of the hybrid power plant is found to be 35.8%, 1.6 percentage points higher than the efficiency of the conventional coal plant, and the total capital investment needed to build and operate a plant is 8050.32 $/kW. This cost is higher than the necessary capital investment of 5979.69 $/kW to build and operate a coal-fired power plant, and it is mainly due to the higher purchased equipment cost. Finally, the levelized cost of electricity of the hybrid plant is found to be 0.19 $/kWh (using both solar and coal resources) and 0.12 $/kWh when the plant is fueled only with coal.

Techno-economic Analysis of Small Scale Electricity Generation from the Lignocellulosic Biomass

In this study, the techno-economic analysis of lignocellulosic biomass conversion to electricity in a small scale power plant was conducted. The proposed process is based on the thermal pathway of electricity production from a carbon content feed. Woods, forest and agricultural residues were considered as the biomass feed, which are available extensively in Iran. Besides, the process benefits not only from the maturity of the method and non-selectivity toward feed but also carbon neutrality and CO2 emission credit income. In order to estimate the minimum selling price (MSP) of the product by this process, the bare module cost model was used. Various equipment sizes were determined by mass and energy balances, whereas the studied power plant capacities were considered 0.5, 1, 5 and 10 MW. The model estimated that the product MSP were 5.83, 4.16, 1.99 and 1.58 ¢/kWh for 0.5, 1, 5 and 10 MW capacities, respectively. Furthermore, a sensitivity analysis was performed to investigate the relative significance of economic parameters on the MSP. The feed, transport, purchased equipment costs and CO2 emission credit income were considered as the sensitivity analysis parameters. Results have proved that the MSP was mainly impacted by the CO2 emission credit income.

Thermo-economic performance analyses and comparison of two turbine layouts for organic Rankine cycles with dual-pressure evaporation

Multi-pressure evaporation organic Rankine cycle involves two or more evaporation processes with different pressures. Compared to the conventional single-pressure evaporation type, the multi-pressure evaporation type can significantly reduce the exergy loss in the endothermic process, and its widely used in the heat–work conversion of low and medium temperature (<350 °C) thermal energy is promising. The turbine layout of the multi-pressure evaporation type has two typical forms: the separate turbine layout and induction turbine layout. Turbines in two layouts may exhibit considerable differences in the geometric and operating parameters. Selecting a suitable turbine layout is crucial to improve the system thermo-economic performance. While, the thermo-economic performance variations and comparison of two turbine layouts remain indeterminate for various operating conditions. This study was based on the one-dimensional efficiency model and purchased equipment cost model of the radial-flow turbine. The thermo-economic performance of two turbine layouts was analyzed and compared for nine pure organic fluids. Effects of two-stage evaporation pressures on the thermo-economic performance of two turbine layouts were also studied. Results show that the total power output of the induction turbine layout can increase by 0.3–5.4%, and its specific investment cost is lower for most of operating conditions and the maximum decrement is 34.2%, compared to the separate turbine layout. The decrement in the specific investment cost decreases as the high-stage evaporation pressure increases, and it generally increases as the low-stage evaporation pressure increases. Moreover, the total power output is larger, the thermo-economic advantage of the induction turbine layout is generally greater.

Integrated bioethanol production from triticale grain and lignocellulosic straw in Western Canada

Triticale is an emerging bioenergy crop in Canada, with potential as a feedstock for the production of ethanol and co-products from both its grain and straw. This study evaluates the commercial potential of introducing triticale as an industrial feedstock crop in the Brown agroecological soil zone of the Canadian Prairies, a semi-arid area which accounts for the highest share of underutilized summerfallow in the region. The study approach includes determination of location parameters (potential triticale land area, feedstock collection radius, and transportation distance), on-farm triticale yield, on-farm production cost, and feedstock chemical composition. Subsequently, SuperPro® Designer was used to develop and simulate two processes using both grain and straw: a) integrated process that ferments both pentose and hexose (Process I); b) single process involving fermentation of hexose sugars only, while pentose sugar is diverted for biogas production and then combined with lignin for power generation (Process II). Triticale on-farm yield is analyzed for the range 5.1–6.8 t ha−1 (which corresponds to 74–126 thousand ha of triticale area). Triticale on-farm production cost is $473 ha−1 with corresponding on-farm profit of $570–$1150 ha−1 from grain and straw sale. The integrated grain and straw processing model is developed and simulated for a 200–550 million L annum−1 ethanol biorefinery, with corresponding total capital investment cost of $140–$240 million. Fermenting both grain and straw and using hydrothermal pretreatment for straw resulted a lower equipment purchase cost per litre of ethanol ($0.12–$0.14 L−1) compared with cellulosic ethanol production using other pretreatment methods ($0.60–$1.24 L−1). The process involving fermentation of both pentose and hexose (Process I) is more profitable compared with a hexose-only process (Process II). Ethanol selling price, plant capacity, and feedstock cost all have high impact on net present value. All plants generate negative net present value at ethanol prices of $0.60 L−1 or less, while a price of at least $0.80 L−1 is required for plants with capacity higher than 250 million L to generate positive net present value. This study provides a basis for further articulation of Canada’s triticale biorefinery concept beyond the near-term goal of producing ethanol, namely, sustainable production of a wide array of bioproducts (bioenergy, biofuels, biomaterials, biochemicals, and biologics) to enhance the profitability of the triticale biorefinery and contribute to Canada’s environmental goals for a bio-based economy.

Time-driven activity-based cost comparison of prostate cancer brachytherapy and intensity-modulated radiation therapy

PurposeTo evaluate the delivery cost of frequently used radiotherapy options offered to patients with intermediate- to high-risk prostate cancer using time-driven activity-based costing and compare the results with Medicare reimbursement and relative value units (RVUs). Methods and MaterialsProcess maps were created to represent each step of prostate radiotherapy treatment at our institution. Salary data, equipment purchase costs, and consumable costs were factored into the cost analysis. The capacity cost rate was determined for each resource and calculated for each treatment option from initial consultation to its completion. Treatment options included low-dose-rate brachytherapy (LDR-BT), combined high-dose-rate brachytherapy single fraction boost with 25-fraction intensity-modulated radiotherapy (HDR-BT-IMRT), moderately hypofractionated 28-fraction IMRT, conventionally fractionated 39-fraction IMRT, and conventionally fractionated (2 Gy/fraction) 23-fraction pelvis irradiation with 16-fraction prostate boost. ResultsThe total cost to deliver LDR-BT, HDR-BT-IMRT, moderately hypofractionated 28-fraction IMRT, conventionally fractionated 39-fraction IMRT, conventionally fractionated 39-fraction IMRT, and conventionally fractionated (2 Gy/fraction) 23-fraction pelvis irradiation with 16-fraction prostate boost was $2719, $6517, $4173, $5507, and $5663, respectively. Total reimbursement for each course was $3123, $10,156, $7862, $9725, and $10,377, respectively. Radiation oncology attending time was 1.5–2 times higher for treatment courses incorporating BT. Attending radiation oncologist’s time consumed per RVU was higher with BT (4.83 and 2.56 minutes per RVU generated for LDR-BT and HDR-BT-IMRT, respectively) compared to without BT (1.41–1.62 minutes per RVU). ConclusionsTime-driven activity-based costing analysis identified higher delivery costs associated with prostate BT compared with IMRT alone. In light of recent guidelines promoting BT for intermediate- to high-risk disease, re-evaluation of payment policies is warranted to encourage BT delivery.

Improving methanol synthesis from carbon-free H2 and captured CO2: A techno-economic and environmental evaluation

Carbon Capture, Utilization and Storage (CCUS) is a widely discussed method that can help reduce carbon emissions of energy intensive plants. The goal of this work is to evaluate from a techno-economic point of view such a plant that uses captured CO2 and renewable H2 obtained in a carbon-free way and produces methanol (MeOH). The paper presents (i) the impact of using a higher conversion rate (30%) than in previously reported works, (ii) the use of a gas turbine and (iii) the addition of organic Rankine cycles (ORC) for reducing the energy consumption. The CCUS plant uses 142.6*106 kg of CO2 annually, reduces the amount of CO2 emitted by 140*106 kg/year and produces 100*106 kg/year of MeOH. H2 is obtained on site, using a water-electrolyzing unit; this consumes 130 MWe and generates the necessary H2 for the process. The proposed MeOH production plant is designed and simulated in ChemCAD. Total purchased equipment cost and operational costs are estimated using the process flow modeling. Key performance indicators (KPI) are calculated using the mass and energy balances obtained. The calculated capital costs are similar to previously reported results in the literature. A rigorous mass and energy integration of the plant resulted in an energetically fully self-sufficient MeOH plant, not taking into account the water-hydrolyzing unit. Electricity price is the main contributor for operational costs, either this should be halved, MeOH prices should increase two times or CO2 prices should increase to 0.255 €/kg to make the process economically viable.

Study of waste heat recovery potential and optimization of the power production by an organic Rankine cycle in an FPSO unit

This paper aims to explore the alternatives for waste heat recovery in a floating production storage and offloading (FPSO) platform to meet the demand for heat (from hot water) and to maximize the electric power generation through the organic Rankine cycle (ORC) with purpose to increase the overall thermal efficiency of the process and reduce CO2 emissions. Two different cycles’ configurations are explored (simple and regenerative) using exhaust gases from the gas turbines as the heat sources for the ORC and the cogeneration system. The curves of the GE LM2500 and GE LM2000 turbines are modeled together with the water heating systems and the organic Rankine cycle. The model is solved using a genetic algorithm optimization method, whose objective function is set to meet the electric power demand for the FPSO platform. The purchased equipment costs of the ORC, the reduction in fuel consumption and CO2 avoided are estimated. Waste heat recovery meets the heat demand and contributes up to 21% of the electric energy demand, which increases the overall efficiency of the system, and improves the utilization factor by up to 10.8% and 19.2%, respectively. There is an average reduction of 22.5% in fuel consumption and CO2 emissions during the lifetime of the FPSO. The economic analysis based on the NPV shows that a US$12.55 million return on investment is possible, in addition to reducing the initial investment cost by US$14.2 million through the exclusion of the GE LM2500 gas turbine at project implementation.

Thermodynamic optimization and thermoeconomic analysis of four double pressure Kalina cycles driven from Kalina cycle system 11

In this paper four configurations of double pressure Kalina cycle system are presented and optimized all of which are modifications of Kalina cycle system 11. In order to set the exact pinch temperature difference an iterative method is applied. Prior to the optimization, the base cycle is validated by comparing the result with a reference. The heat transfer fluid of the inlet stream is supposed to be the product of combustion at 3 different temperatures, 383.15K, 413.15K and 443.15 and the results are compared at the base case and the optimum conditions. In order to present a thorough evaluation, thermoeconomic analysis is also presented in which levelized cost of electricity is selected as the criterion. Different decision variables can be defined for the cycles based on the cycle’s degrees of freedom. Pressure levels, mass flow rate and ammonia concentration of the base stream and split ratio are the decision variables. Exergy efficiency is considered as the objective function and the innovated double pressure Kalina cycles as well as the base Kalina cycle are compared. Results show that the Kalina cycle system named 112b is the most efficient cycle at the base condition. It is also shown that by increasing the heat source temperature the exergy efficiency and the purchased equipment cost at the optimum condition rises while the levelized cost of electricity lowers. Thermoeconomic evaluation indicates that at both base and the optimum conditions, the levelized cost of electricity of the base cycle is less.

Ruhrpumpen invests in new manufacturing plant in India

Fracturing equipment is the core device in shale gas reservoir stimulation. As domestic shale gas exploration and development steps into deep layers, the development of fracturing technology puts forward higher requirements for relevant equipment. Electric drive is an important development direction of fracturing equipment technology. In this paper, the technical progress of electric drive fracturing equipment in China and abroad was investigated. It is shown that a high-power frequency conversion system is the key technology to determine the performance of electric drive fracturing equipment. After the adaptability of the high-power frequency conversion technology to electric drive fracturing equipment was analyzed, based on the fracturing operation of Model 2500 electric drive fracturing trucks in the Weiyuan Block of the Sichuan Basin for shale gas reservoir stimulation, electric drive and diesel-driven fracturing equipment were comparatively analyzed from the aspects of economic and technical indicators. And the following research results were obtained. First, compared with a diesel-driven fracturing truck of the same power, an electric drive fracturing truck can realize a full power coverage and a continuous adjustment of output displacement, and can better meet the operation requirements of fracturing process for a precise control of the pumping displacement, while reducing the power cost by 68% and the equipment purchase cost by 10–20%. Second, compared with the skid mounted equipment, an electric drive fracturing truck has a better transport performance, being suitable for the fracturing well sites with poor road conditions, such as loess gullies, hills and mountains. It is suggested that the following development direction of the electric drive fracturing equipment should focus on the improvement of single machine power density. In addition, it is recommended to enhance the basic studies on high-pressure and high-power semiconductor devices and make a good plan for the power demand of shale gas platform construction in advance, so as to give a better play to the operating cost advantage of electric drive fracturing equipment.

An assessment of farm scale biomass pelleting in the Northeast

Farm scale pellet production is a promising opportunity for farmers and landowners interested in producing a renewable biomass fuel. However, the true costs and performance of these systems in a farm setting is not fully understood. A feasibility analysis was carried out on the farm-scale switchgrass production operation at Wood Crest Farm near Berwick, PA as a representative example of operations in the region. Farmer interviews and direct measurements of equipment performance, energy use, and labor requirements were recorded for all stages of the operation. Results indicate that the production of pellets at this facility costs $98 per tonne, excluding labor, equipment and land purchase costs. As such, this represents a “bare bones” operating cost. Including the cost of labor brings the cost to about $307 per tonne. Thus, production may only be economically feasible when land, equipment, and labor are available at marginal or reduced cost. Every joule of energy input into the operation yielded 7.8 J of energy in the pellet fuel. There appears to be potential to reduce operating costs by increasing pelletizer yield and/or automating pelletizer operations - two opportunities for engineered solutions in this sector that can render the operation financially viable even when labor costs are included. On-farm pelleting in the Northeast US appears to have potential to be cost competitive with commercial wood pellets in select scenarios, and has the potential to be more widely applicable if modest improvements are made to process efficiency.

Unravelling uncertainty and variability in early stage techno-economic assessments of carbon capture technologies

This paper addresses the uncertainty and variability in techno-economic studies of carbon capture technologies, based on a detailed comparison of the results of different studies on postcombustion CO2 capture with advanced amines, and on an in-depth uncertainty analysis using a combination of sensitivity and pedigree analyses. The results show that despite efforts to harmonize capital cost estimates, the capital cost results of the same PCC carbon capture systems can still show large (65%) differences. This uncertainty may simply be inherent to early stage cost estimates. Amongst the most important causes for the variability shown in this work are differences in equipment sizing methods and purchased equipment cost estimates. This capital cost variability only mildly propagates into the Levelised Cost of Electricity and Cost of CO2 Avoided, more so in case of low power plant utilisation scenarios. To enhance insight into these uncertainties and enable their communication, the paper argues to use in-depth uncertainty evaluation for early stage techno-economic studies. It suggests to complement current practice of sensitivity analysis with pedigree analysis and to combine the results of both analyses in diagnostic diagrams. This may lead to more informed interpretation of the results of techno-economic studies, and helps focus techno-economic research efforts towards the parameters that most influence final performance indicators.

English

Tropical Africa has one of the world’s largest endowments in medicinal plant diversity. However, this potential has not been translated into pure drugs of proven efficacy and safety synonymous with modern pharmaceuticals. The basis for the slow translation of Tropical Africa’s medicinal plant wealth into value-added medicines acceptable in the doctor’s clinic is not clear. In this work, we sought to understand the patterns of research on African medicinal plants in general, and the capacity of sub-Saharan universities to conduct value-building research on plant-derived medicines in particular, using an extensive online search. A near-exponential growth in number of publications over the period 2000 to 2015 was found. However, most of the primary literature is on preliminary pharmacological assays and ethnobotany/ethnopharmacology. Only 6% of the publications are on advanced investigations such as isolation, structure elucidation and semi-synthetic optimization of natural compounds, structural studies of drug targets, ligand binding studies and cell biological assays, yet they are fundamental to progression of lead compounds into useful drugs. Assessment of the current biomolecular infrastructure in 25 sub-Saharan universities found severe shortage of essential equipment in many of them. Only 64, 68, 36 and 68% of the sampled universities have high performance liquid chromatography (HPLC), gas chromatography-mass spectrometry (GC-MS), liquid chromatography-mass spectrometry (LC-MS), and nuclear magnetic resonance (NMR) equipment, respectively. East, Central and West Africa are particularly deficient in most of the key equipment, and some available are non-functional. The purchase cost of most biomolecular research equipment is between USD 30,000 and USD 500,000. Further analysis shows that the cost of establishing comprehensive biomolecular research infrastructure in at least one university per sub-Saharan nation is negligible relative to their gross domestic products (GDPs). Thus, even with the current economic resources, sub-Saharan African countries would upgrade biomolecular research capabilities in their leading universities without disrupting other economic priorities. Key words: Medicinal plants, biomolecular, Tropical Africa, nuclear magnetic resonance (NMR), liquid chromatography-mass spectrometry (LC-MS), gas chromatography-mass spectrometry (GC-MS), analog synthesis.

Methanol synthesis using captured CO2 as raw material: Techno-economic and environmental assessment

The purpose of this paper is to assess via techno-economic and environmental metrics the production of methanol (MeOH) using H2 and captured CO2 as raw materials. It evaluates the potential of this type of carbon capture and utilisation (CCU) plant on (i) the net reduction of CO2 emissions and (ii) the cost of production, in comparison with the conventional synthesis process of MeOH Europe. Process flow modelling is used to estimate the operational performance and the total purchased equipment cost; the flowsheet is implemented in CHEMCAD, and the obtained mass and energy flows are utilised as input to calculate the selected key performance indicators (KPIs). CO2-based metrics are used to assess the environmental impact. The evaluated MeOH plant produces 440ktMeOH/yr, and its configuration is the result of a heat integration process. Its specific capital cost is lower than for conventional plants. However, raw materials prices, i.e. H2 and captured CO2, do not allow such a project to be financially viable. In order to make the CCU plant financially attractive, the price of MeOH should increase in a factor of almost 2, or H2 costs should decrease almost 2.5 times, or CO2 should have a value of around 222€/t, under the assumptions of this work. The MeOH CCU-plant studied can utilise about 21.5% of the CO2 emissions of a pulverised coal (PC) power plant that produces 550MWnet of electricity. The net CO2 emissions savings represent 8% of the emissions of the PC plant (mainly due to the avoidance of consuming fossil fuels as in the conventional MeOH synthesis process). The results demonstrate that there is a net but small potential for CO2 emissions reduction; assuming that such CCU plants are constructed in Europe to meet the MeOH demand growth and the quantities that are currently imported, the net CO2 emissions reduction could be of 2.71MtCO2/yr.

Thermodynamic and economic analysis for the pre-feasibility study of a binary geothermal power plant

Maximum power output and thermal conversion efficiency are the goals of ORC thermodynamic analysis. Co-optimization of energetic performance and system cost is needed for pre-feasibility design analysis. This paper presents a pre-feasibility design investigation for a binary geothermal power plant using a typical geothermal resource in New Zealand. Thermodynamic and economic analyses were conducted for key cycle design options, a range of working fluids and component selection parameters. The net electrical power output (Wnet) and the ratio of Wnet to total Purchased Equipment Cost (PEC) are used as the objective function to select the most thermo-economical designs. Three working fluids n-pentane, R245fa and R134a are investigated. The thermodynamic analysis shows that the net electrical power output (Wnet) of cycle design achieves a maximum level at a certain optimum turbine inlet pressure and mass flow rate of working fluid. The 2-stage designs produce higher Wnet and thermal and exergy efficiencies than the 1-stage designs. Economic comparison indicates that the type of working fluid and cycle configuration have a great effect on economic performance as measured by PEC. The profitability analysis was conducted for the top three options. The results indicate that a standard Rankine cycle with a 2-stage turbine using n-pentane is the most thermo-economical design for the particular brine resource and re-injection conditions.

Promises and challenges of fluorescence cystoscopy

IntroductionFluorescence based photodynamic diagnostic (PDD) techniques have been developed to improve detection and treatment of non-muscle invasive bladder cancer. The goal of this article is to evaluate the promises and challenges of blue light cystoscopy. MethodsThe literature was reviewed regarding articles pertaining to fluorescent cystoscopy and blue light cystoscopy (BLC). ResultsBlue light cystoscopy improves detection of bladder cancer tumors especially CIS. Randomized trials have demonstrated a reduction of recurrences. BLC has been demonstrated to be safe and effective in treatment of NMIBC of varying risk. The main obstacle to BLC will be adoption by urologists. Purchase cost of capital equipment may impact usage especially if adopted for outpatient clinics. ConclusionsBLC has been demonstrated to be safe and effective in treatment of NMIBC of varying risk. The reduction of recurrences and yet unproven but potential reduction in progression should be viewed favorably by urologists and patients. The main obstacle to BLC will be adoption by urologists who can put pressure on hospitals to acquire the capital equipment and who will seek the training to become proficient in using the technology. Patient demand for the technology may also help increase availability. Finally, the companies involved with BLC need to support trials that will demonstrate reduction in progression and that will answer the practical issues regarding usage in proximity to BCG and repeated usage.

Optimization of micro combined heat and power gas turbine by genetic algorithm

In this paper, a comprehensive thermodynamic modeling and multi-objective optimization of a micro turbine cycle in combined heat and power generation, which provides 100KW of electric power. This CHP System is composed of air compressor, combustion chamber (CC), Air Preheater, Gas Turbine (GT) and a Heat Recovery Heat Exchanger. In this paper, at the first stage, the each part of the micro turbine cycle is modeled using thermodynamic laws. Next, with using the energetic and exergetic concepts and applying economic and environmental functions, the multi-objectives optimization of micro turbine in combined heat and power generation is performed. The design parameters of this cycle are compressor pressure ratio (rAC), compressor isentropic efficiency (?AC), GT isentropic efficiency (?GT), CC inlet temperature (T3), and turbine inlet temperature (T4). In the multi-objective optimization three objective functions, including CHP exergy efficiency, total cost rate of the system products, and CO2 emission of the whole plant, are considered. Theexergoenvironmental objective function is minimized whereas power plant exergy efficiency is maximized usinga Genetic algorithm. To have a good insight into this study, a sensitivity analysis of the result to the fuel cost is performed. The results show that at the lower exergetic efficiency, in which the weight of exergo-environmental objective is higher, the sensitivity of the optimal solutions to the fuel cost is much higher than the location of the Pareto Frontier with the lower weight of exergo-environmental objective. In addition, with increasing exergy efficiency, the purchase cost of equipment in the plant is increased as the cost rate of the plant increases.

Prediction Technology of Power Transmission and Transformation Project Cost Based on the Decomposition-Integration

Through the analysis of power transmission and transformation project cost, total cost can be decomposed into construction cost, equipment purchase cost, installation cost, and other costs. This paper proposes a decomposition-integration cost prediction model taking a substation project as an example by fully considering the cost characteristics. In decomposition module, the total cost is decomposed into four expenses. In prediction module, different forecasting models are selected to forecast different expense. In integrated module, choose different integration methods to get the predicting results of total cost. The empirical results show that decomposition-integration prediction algorithm has good effect which can effectively predict the cost of power transmission and transformation project and has practical application and popularization value.

Estimating road management equipment inventory needs and associated purchase costs

This paper presents a method for estimating road management equipment inventory needs and associated purchase costs. The primary feature of this method is to consider historical operations records by road management equipment type and weights by work type based on subjective preferences of the public agencies. The Analytical Hierarchy Process (AHP) is employed as the main tool to reflect the relative importance of a day-to-day road management activity. In order to examine the appropriateness of our method, we performed a case study with 18 regional transportation offices in South Korea. The estimated cost of equipment purchases across these offices was approximately 41 million US dollars based on the 2011 year (when apply average unit cost by equipment), while the actual equipment purchase costs during the same one-year period were about 44 million US dollars. The main reason for the differences of estimates across offices is due to unit cost by equipment, road conditions, relative importance of management tasks, and omission of unused equipment in inventories and use of labor. We also developed estimates using the maximum unit costs by equipment, in order to provide an upper bound to the authorities. Using those values we estimated the annual cost at approximately 60 million dollars. The estimates developed can provide useful information to road authorities when they establish annual plans for road management.

Acid Wash Scrubbing as a Countermeasure for Ammonia Emissions from a Postcombustion CO2 Capture Plant

Amine-based absorption-desorption processes are considered to be the state-of-the-art technology for CO2 capture. However, the typical amines used are susceptible to oxidative and thermal degradation. Ammonia is formed as a result of oxidative solvent degradation. Because of the volatility of ammonia, significant emissions of ammonia can occur. Emission countermeasures such as water washing and use of demisters are ineffective against highly volatile components such as ammonia. The aim of this study is to demonstrate acid washing as a countermeasure for ammonia emissions. The tests were carried out at TNO's CO2 capture plant at Maasvlakte, The Netherlands. Aqueous monoethanolamine (MEA, 30 wt %) was used as the absorption liquid. Typical ammonia emissions at the water wash outlet were in the range of 15-20 mg/Nm3, as measured by Fourier transform infrared (FTIR) spectroscopy. An acid wash scrubber using sulfuric acid was installed downstream of the water wash. Parametric tests based on changing the pH and flow rate of the acid liquid and the temperature of the treated flue gas were performed to assess the efficiency of the acid wash scrubber. Additional ammonia (up to 150 mg/Nm3) was spiked in the treated flue gas to test the acid wash scrubber, even under extreme conditions. The results from the experiments were compared with a model made in Aspen Plus. The experimental results indicated that it was possible to reduce ammonia emissions below 5 mg/Nm3 at a pH of 6 for both spiking and nonspiking experiments. The modeling results were in good agreement with the experimentally measured ammonia emissions. The breakthrough of ammonia capture, defined as less than 20% capture efficiency, was found to be at lower pH, 6.8 for nonspiking experiments and 8.1 for spiking experiments, than for the model, which predicted breakthrough at pH 8.7 for nonspiking experiments and 9.7 for spiking experiments. Changes in the acid liquid and treated flue gas temperature did not have an impact on the capture of ammonia. MEA emissions were also below 3 mg/Nm3 at the acid wash scrubber outlet. It is estimated that the purchased equipment cost of an acid wash is about €3.75 million for an 800-MWe-scale postcombustion CO2 capture plant. © 2014 American Chemical Society.