Techno-economic Considerations Research Articles

Techno-economical and practical considerations for SHM systems

Nowadays, the increasing demand of Structural Health Monitoring (SHM) systems, either for research or specific monitoring applications, is posing several questions on their technical and economical sustainability. In general, the initial cost of a full scope and long-term SHM system is significant, but also, the operational and maintenance costs have an important role. In practice, it has been found that there is a correlation between the cost of the SHM system and its main monitoring scope, including the size and complexity of the structure to be monitored. Additional considerations must include peripheral systems (hardware and software) to process, analyze and to store data efficiently for long-term evaluations. Even though, most SHM systems are designed assuming that the benefits overweight the costs. In practice, the payback from technical knowledge, maintenance reduction costs, safety or reliability, are not easy (if not impossible) to quantify. While most engineers and researchers are thinking on sophisticated techniques and more efficient or accurate sensors, the users concerns are on practical and economic issues to justify the initial investment and the cost to operate the monitoring system. Cost-benefit or cost-efficiency analysis is not an ordinary practice for researchers, but is becoming a standard requirement for infrastructure investment projects. In this document, the guidelines for the preparation and presentation of cost and benefit analysis of investment programs and projects required by the Mexican Government, are used to evaluate some specific SHM systems of highway bridges. In general, it is found that the main challenge for these analyses is the availability of conclusive information to justify the sustainability of the monitoring projects, especially those which are related to the benefits.

Techno Economic Optimization of Petlyuk Distillation Column Design Using Duelist Algorithm

Distillation process consume huge energy hence one of the method for reducing it is by applying Petlyuk configuration. In design stage, the important thing is the minimum number of trays. In this paper, four methods of Petlyuk configuration design were compared i.e. the short-cut method, the modified method using Winn equation, Vapor-Liquid Equilibrium (VLE) approach and the proposed method that incoorporated Duelist Algorithm Optimization (DAO) method and VLE approach. Optimization was performed by techno economic consideration. The objective is minimizing the total annual cost for operating period over 10 years. The maximum saving about 34,38% was provide when the actual number of trays at prefractionator and at main column are 3 and 109, respectively, and it's related operating condition.

Thinking big? Ghana, small reactors, and nuclear power

Ghana has been seen as a potential market for small nuclear reactors and Ghanaian nuclear officials have, on occasion, expressed an interest in such reactors. However, Ghana seems to be heading towards procuring a reactor from Russia with a capacity of 1000–1200MW. A power plant with such a large power generation capacity is not appropriate to Ghana’s limited electricity grid or its financial circumstances. This paper examines the likely reasons for this focus and argues that despite greater government interest in setting up nuclear reactors, Ghana’s nuclear establishment may not have the political clout to force through the purchase of a reactor, and has therefore attempted to position itself as a complete, one-stop solution to Ghana’s electricity crisis, by calling for the construction of just one or two large nuclear power plants. The paper draws on the role of discursive elements in energy policy making, discusses the policy implications of this reactor choice, and offers evidence for the proposition that decision about nuclear power are not made on the basis of merely techno-economic considerations but are driven by a range of social and political factors.

Architectures for scalable integrated photo driven catalytic devices-A concept study

Architectures with various degrees of integration are investigated for water splitting devices using the energy of light for fuel production. The many approaches presented in literature for such ‘photo driven catalytic (PDC) devices’ are reviewed and discussed in perspective of their scalability to large area. Then, back-of-the-envelope type techno-economic considerations for such systems are presented. Compared to the benchmark, consisting of large electrolyzers coupled to the grid, it was found that PDC devices could be competetive in places with high irradiation, given the assumption that no compromises on system stability have to be made compared to stand-alone PV-systems for electricity generation. In agreement with literature, it was found that the cost of the PV part dominate the hydrogen generation costs, based on today's technology. Thus, device architectures that allow low cost PV (by e.g. avoiding use of costly materials or introducing further inherent loss mechanisms) are considered the most promising ones.

Hybrid PV and solar-thermal systems for domestic heat and power provision in the UK: Techno-economic considerations

A techno-economic analysis is undertaken to assess hybrid PV/solar-thermal (PVT) systems for distributed electricity and hot-water provision in a typical house in London, UK. In earlier work (Herrando et al., 2014), a system model based on a PVT collector with water as the cooling medium (PVT/w) was used to estimate average year-long system performance. The results showed that for low solar irradiance levels and low ambient temperatures, such as those associated with the UK climate, a higher coverage of total household energy demands and higher CO2 emission savings can be achieved by the complete coverage of the solar collector with PV and a relatively low collector cooling flow-rate. Such a PVT/w system demonstrated an annual electricity generation of 2.3MWh, or a 51% coverage of the household’s electrical demand (compared to an equivalent PV-only value of 49%), plus a significant annual water heating potential of to 1.0MWh, or a 36% coverage of the hot-water demand. In addition, this system allowed for a reduction in CO2 emissions amounting to 16.0 tonnes over a life-time of 20years due to the reduction in electrical power drawn from the grid and gas taken from the mains for water heating, and a 14-tonne corresponding displacement of primary fossil-fuel consumption. Both the emissions and fossil-fuel consumption reductions are significantly larger (by 36% and 18%, respectively) than those achieved by an equivalent PV-only system with the same peak rating/installed capacity. The present paper proceeds further, by considering the economic aspects of PVT technology, based on which invaluable policy-related conclusions can be drawn concerning the incentives that would need to be in place to accelerate the widespread uptake of such systems. It is found that, with an electricity-only Feed-In Tariff (FIT) support rate at 43.3p/kWh over 20years, the system cost estimates of optimised PVT/w systems have an 11.2-year discounted payback period (PV-only: 6.8years). The role and impact of heat-based incentives is also studied. The implementation of a domestic Renewable Heat Incentive (RHI) at a rate of 8.5p/kWh in quarterly payments leads to a payback reduction of about 1year. If this incentive is given as a one-off voucher at the beginning of the system’s lifetime, the payback is reduced by about 2years. With a RHI rate of 20 p/kWh (about half of the FIT rate) PVT technology would have approximately the same payback as PV. It is concluded that, if primary energy (currently dominated by fossil fuels) and CO2 emission minimisation are important goals of national energy policy, PVT systems offer a significantly improved proposition over equivalent PV-only systems, but at an elevated cost. This is in need of careful reflection when developing relevant policy and considering technology incentivation. Currently, although heat outweighs electricity consumption by a factor of about 4 (by energy unit) in the UK domestic sector, the support landscape has strongly favoured electrical microgeneration, being inclined in favour of PV technology, which has been experiencing a well-documented exponential growth over recent decades.

Stochastic techno-economic considerations in biodiesel production

Biodiesel production, like other engineering projects, involves critical decisions which have to be made under uncertainties stemming from a range of sources such as the inherent variation in operating conditions and market forces featuring inflation, depreciation factors, variations in equipment/production costs, etc. Although the effect of such uncertainties on front end engineering and management decisions was recognised, these have not been considered comprehensively in the literature. In this paper, for the first time, structural reliability principles are applied to determine the prospect of a process plant achieving some performance targets under uncertainties. Considering the published case of a biodiesel production plant, this paper presents a new approach for techno-economic assessment in a stochastic framework. Mean values of the economic indicators obtained through the stochastic analysis are found to be in good agreement with previously published nominal values. The stochastic techno-economic analysis approach combines First Order Reliability Method (FORM) and Monte Carlo Simulation (MCS) to offer additional performance measures which are needed by prospective investors, governments, engineers and other stakeholders to ensure plant safety and cost-efficiency.

Upgrading of wood pre-hydrolysis liquor for renewable barrier design: a techno-economic consideration

A techno-economic assessment of an upgrading procedure and outtake of a pre-hydrolysate in a presumed dissolving pulp mill was performed. Pre-hydrolysis of spruce wood chips in pilot scale produced input data for energy and mass balances and was performed with and without subsequent membrane filtration to produce hydrolysate fractions rich in galactoglucomannan and with some lignin. The hydrolysate is a viable raw material for the production of renewable thin oxygen barrier films as demonstrated herein in the formulation of free standing films with very low oxygen permeability at both moderate and high relative humidities. Approximately 50,000 ton dry solid upgraded pre-hydrolysate suitable for production of oxygen barriers could be produced according to the presumed dissolving pulp mill producing about 500,000 air dry ton dissolving pulp per year and applying a liquor to wood ratio of 4:1. Utilization of the pre-hydrolysis liquor hence adds value to and realizes the dissolving plant as a biorefinery. A sensitivity analysis indicates that the market price of the upgraded pre-hydrolysate has the largest positive effect on the return on investment for separation and upgrading of a pre-hydrolysate. Increased investment cost and increased annuity factor show negative effects.

Optimal design and operation of pressurized oxy-coal combustion with a direct contact separation column

Simultaneous multi-variable gradient-based optimization is performed on a 300 MWe wet-recycling pressurized oxy-coal combustion process with carbon capture and sequestration. A direct contact separation column is utilized for practical and reliable low-temperature thermal recovery. The models for the components include realistic behavior like heat losses, steam leaks, pressure drops, and cycle irreversibilities. Moreover, constraints are used for technoeconomical considerations. Optimization involves 17 optimization variables and 10 constraints, with the objective of maximizing the thermal efficiency. The optimization procedure utilizes recent design rules and optimization procedures for optimal Rankine cycle performance speeding up the plant optimization process by eliminating variables and avoiding constraint violations. Moreover, the procedure partially alleviates convergence to suboptimal local optima. The basecase of the study is a comprehensively optimized cycle that utilizes a surface heat exchanger, a more thermodynamically-effective form of thermal recovery which however bears significant materials challenges. Upon optimization, the cycle utilizing the direct column is seen to be very attractive regarding efficiency and performance. Moreover, the optimization results unveil potential for reducing capital costs by eliminating the first carbon sequestration intercooled compressor and by showing possibilities of process intensification between the separation column and the carbon sequestration purification columns.

Multi-variable optimization of pressurized oxy-coal combustion

Simultaneous multi-variable gradient-based optimization with multi-start is performed on a 300 MWe wet-recycling pressurized oxy-coal combustion process with carbon capture and sequestration. The model accounts for realistic component behavior including heat losses, steam leaks, pressure drops, cycle irreversibilities, and other technoeconomical considerations. The optimization study involves 16 variables, three of which are integer valued, and 10 constraints with the objective of maximizing thermal efficiency. The solution procedure follows active inequality constraints which are identified by thermodynamic-based analysis to facilitate convergence. Results of the multi-variable optimization are compared to a pressure sensitivity analysis similar to those performed in literature; the base-case of both assessments performed here is a favorable solution found in literature. Significant cycle performance improvements are obtained compared to this literature design at a much lower operating pressure and with moderate changes in the other operating variables. The effect of the variables on the cycle performance and on the constraints are analyzed and explained to obtain increased understanding of the actual behavior of the system. This study reflects the importance of simultaneous multi-variable optimization in revealing the system characteristics and uncovering the favorable solutions with higher efficiency than the atmospheric operation or those obtained by single variable sensitivity analysis.

Potential of community level utilization of coconut shell and stem wood for charcoal and activated carbon in Kerala

Since the production of activated carbon at present being limited to large scale industries, an attempt was planned to develop an appropriate clean technology to produce activated carbon in the cluster or community based organizations. As the existing method of employing rotary kiln for the large industrial scale production of activated carbon has very little scope for down-scaling due to techno-economic considerations, fluidized bed reactor (FBR) system was identified as the appropriate technology for small or community level production of active carbon. Both the charcoal and activation plants were designed for continuous operation by way of operating three shifts per day. As pilot plants, a continuous vertical carbonizing plant with an input capacity of 3 tones raw material (coconut shell) per day, which can produce about one tone charcoal per day and an FBR with an input capacity of 0.25 tone charcoal per day, which can produce 0.125 tone of active carbon, was successfully designed, fabricated, installed, trial runs were conducted, optimized the process parameters for desired quality products, and assessed the quality of products for industrial use. The design drawings, description and operational details of the newly developed pilot plants are ready for commercialization. The quality of charcoal and the granular shell active carbon produced were found conforming to Indian standards. The details of the plants developed (1 tone output capacity charcoal plant and 0.125 tone output capacity FBR activation plant) as well as yield and quality assessments are given in this report. Economic analysis of the pilot plants developed showed that a minimum up-scaling of the plants to a level of a input capacity utilization of 6 tones of shells per day is financially viable for self-sustaining. Both the plants developed are pollution free and techno-economically suitable for cluster or community level production of charcoal and activated carbon after due up-scaling to the required capacity. As far as conversion of waste coconut stem wood is concerned, it was found that the plant can produce stem wood charcoal with moderate yield and quality. The inherent quality of stem wood charcoal, its poor hardness, makes it unsuitable for the manufacture of activated carbon. Stem wood charcoal is suggested for using as direct fuel or as an ingredient for fuel briquettes.

Treatment of pesticides containing effluents using organoclays/nanofiltration systems: rational design and cost indicators

Removal of hazardous pollutants from wastewater is an essential step for safe recovery and reuse. The immediate objective of this paper is to discuss functional requirements and design considerations of a nanofiltration (NF)-based system for the treatment of pesticide industry effluents and contaminated surface water. Techno-economic considerations for a 100 m3/d membrane filtration plant for the treatment of pesticide industry effluents and contaminated agricultural drainage water are presented. Metolachlor has been selected as the model for pesticide removal. The proposed system comprises membrane ultrafiltration (UF), NF, and adsorption of pesticides using modified clays such as organoclays. This paper is concluded with design guidelines and indicators pertinent to the treatment of pesticide-containing wastewater using NF systems. The estimated capital cost of a 100 m3/d treatment facility amounts to $ 240,850. Further, the treatment cost is about $1.77/m3.

Techno-Economic Considerations in the Commercial Microwave Processing of Mineral Ores

Microwave heating of mineral ores had previously been shown to result in process benefits such as reduced strength and improved mineral liberation, but the economics of the process were not attractive and no attention was given to feasible scale up. This paper provides an overview of the multi-disciplinary approach that has been required to address these failings and develop the technology to pilot scale. Thermal stress simulations show that the operation at high power densities and short residence times is the optimal operating strategy. Experiments using high power densities (>109 W/m3 absorbing phase) and short residence times (˜ 0.1 s) were used to confirm that the benefits can now be achieved at economically viable microwave energy inputs (˜ 1 kWh/t). In order to design applicators, reliable measurement of effective microwave properties of crushed ores is required. A new method has been developed to extract dielectric properties when the sample thickness is a multiple of half a guide wavelength at some point in the measurement band. Finite difference time domain modelling has been used to design and simulate applicators. A transverse E field applicator with a reflection compensating step has been developed, and a unit with a capacity of > 10 tons/h is being tested. Preliminary economic analysis shows that the overall cost of the process will be between US$ 0.16–0.85 per ton of ore.

Optimal use of coal for power generation in India

There is growing consensus among energy planners that electricity requirements in India would increase rapidly in the next couple of decades, and that coal would continue to dominate the generating capacity mix. Comparatively high levels of ash in Indian coal causes concern both in terms of the high costs of coal movement and the associated environmental impacts. As per the notification of September 1997, all power plants located in sensitive areas, metropolitan cities and in areas distant from the coalfields, must use coal with <34% ash. However, little progress has been made towards coal beneficiation and some consumers have already started to import non-coking coal for blending in order to comply with environmental requirements. The importance of planning for optimal utilization and transportation of thermal coal cannot be underestimated, especially at a juncture where the Indian coal industry is already facing competition from rising imports of non-coking coal. This paper assesses the optimality of the current patterns of coal movement and examines the economics of beneficiating thermal coals. A linear programming model has been developed based on the framework of the general transportation problem. The authors conclude that the washery is not economically attractive given the current costs, beneficiation technique and quality of Indian non-coking coal. Model simulations have been attempted to assess the possibility of coal beneficiation based on techno-economic considerations rather than political or other considerations. The paper also stresses the possibility of overall gains to the economy by modifying the current patterns of coal movement.

CULTIVATION OF MEDICINAL AND AROMATIC PLANTS IN INDIA - A COMMERCIAL APPROACH

CULTIVATION OF MEDICINAL AND AROMATIC PLANTS IN INDIA - A COMMERCIAL APPROACH

Arbitrated Sharing of Traffic in Telecommunication Networks: Technoeconomical Considerations

The technoeconomical aspects of implementing an arbitrated sharing of telecommunication traffic by CO (class 5) circuit-switches are studied. The traffic in question refers voice calls and dial-up modem data supported on network access lines terminated at the circuit-switches. Such time-division multiplexed (TDM) services still remain as the major revenue-earning products of public switched telephone network service-providers (and this i>status i>quo is expected to continue over several future years, despite of xDSL and/or IP-network penetrations). As such, this study was motivated to address an engineering effort to realize higher revenue-potentials through prudent sharing of the traffic between the circuit-switches. This arbitration in traffic-sharing is based on the diversity in the dynamics of traffic-demand posed by different subscribers (such as suburban-based residential customers and urban-based commercial end-users). The centum call seconds (CCS) metric is adopted to specify the traffic-load commensurate with the voice/dial-up modem sources. The heuristics of fair-proportioning considerations that let the switches serving a diverse population of subscribers so as to optimally vary (share) the traffic-load between switches i>via an arbitrated approach is discussed. Relevant metric for arbitration is defined in terms of a cross-entropy based complexity measure and an implementation scheme is proposed thereof. Computed results on traffic sharing algorithm are presented and discussed.

Environmental-impact assessment of hydro-power in Egypt

The environmental impact of energy production and use with the associated emissions of greenhouse gases, particularly CO 2, has created much attention and growing concern at both national and international levels. In Egypt, efforts have been directed to incorporate the environment-protection issues within the overall planning of the energy sector, as appropriate to its national commitment and its techno-economic considerations. Over the past decade, 1985–1995, hydro-power had contributed between 28 and 22% of the total energy produced by Egyptian power-plants, while the contribution of the hydro capacity was between 32.4 and 21.5%. Many studies have been carried out on the impacts of the Aswan High Dam on various aspects of the environment. An objective evaluation of the Dam, based on 25 years of operational data, indicated that it has overall been positive even though it has contributed to some environmental problems. These problems, however, are significantly less than most people originally expected. This paper deals with the review and analysis of the detrimental effects of hydro-power in Egypt. An evaluation will be given of the emissions of greenhouse gases from the whole hydro-chain.

Technoeconomic considerations in reverse osmotic concentration of seawater

Conditions of reverse osmotic concentration of seawater as the first step in the salt production are analysed. By separating out two third of the total water content of seawater the bulkiest phase in the salt production could be remarkably accelerated. Reverse osmotic concentration can be accomplished in a two-stage process with a moderate membrane rejection factor in the first stage. The seawater concentration is accompained by the fresh water production in the second stage. The analysis of the technoeconomical data justifies the principle, and shows that it could be successfully implemented.

Techno-Economic Consideration Concerning Appropriate Technologies

Publisher Summary This chapter discusses techno-economic consideration concerning appropriate technologies. Simply appropriate technologies could be defined as those keeping economic, social, and environmental objectives of development. The concept of appropriate technology has to be accepted from the developing countries as an instrument of economic development with social justice. Mainly three elements are relevant and leading to the choice of appropriate technologies: goals, resources, and economic and social constraints. The goals of development are easy to describe. In case of developing countries, they may be summarized in raising the national income and self sufficiency. Mostly in developing countries, natural resources are not fully scanned and programmed for utmost utilization. Economic and social constraints include the environment, social structure, inherent culture, traditions, market size, financing educational state, and infrastructure.

Reliability Studies of Community Television Receivers for Satellite Instructional Television Experiment (SITE)

In this paper various failures that occur in solidstate television receivers have been briefly discussed. Reliability calculations like Failure Rate, Mean Time Before Failure, etc., have been presented and suggestions made for minimizing the down-time of the receiver particularly from technoeconomic considerations.

A discussion on ship technology in the 1980s - A forward view of British shipping

The author’s theme is that the forward view of British shipping over the time span being considered will be to a large extent a view of existing ships. The industry is too capital intensive, too highly geared and operates at too low a level of profitability to admit of a very rapid change. Developments in the future must be based on the profitability of the present. It must be anticipated that in the early part of the period considered, a great part of the developments will be concentrated on improving the efficiency of the existing industry. Future developments will be dictated by techno-economic considerations. It is likely to be the middle 1980s before the scene is substantially changed by nuclear power and fluidics. A major technical development of the middle part of the period will be the growth of a fleet of liquid gas carriers for which gas turbines will provide the main propulsion system.