Supercritical Plant Research Articles

Cost estimation for CO2 supercritical extraction systems and manufacturing cost for habanero chili

An equation to estimate the costs of industrial size supercritical extraction systems was developed and used to estimate the cost of manufacturing (COM) of habanero pepper oleoresin on extraction cells ranging from 5 to 400L. The correlation was based on quoted costs obtained for five different sizes of supercritical extraction plants, and took into consideration inflation with the use of a cost index for a chemical engineering plant. COM for habanero chili was based on experimentation developed on a cell 0.1L.

Thermodynamic, ecological and economic aspects of the use of the gas turbine for heat supply to the stripping process in a supercritical CHP plant integrated with a carbon capture installation

This paper presents the results of thermodynamic and economic analyses for eight variants of a combined heat and power (CHP) plant fuelled with coal working under supercritical steam parameters and integrated with a CO2 capture installation and a gas turbine system. The motivation behind using a gas turbine in the system was to generate steam to supply heat for the stripping process that occurs in the separation installation to regenerate the sorbent. Additional analyses were conducted for the reference case, a CHP unit in which the CO2 separation process was not conducted, to enable an economic evaluation of the integration of a CHP unit with a CO2 separation installation according to the variants proposed. The break-even price of electricity and avoided emission costs were used to evaluate the respective solutions. In this paper, the results of the sensitivity analysis of the economic evaluation indicators in terms of the change in the annual operation time, price of emission allowance and heat demand rate for the realization of the stripping process for all cases are presented.

Hybridisation of solar and geothermal energy in both subcritical and supercritical Organic Rankine Cycles

A supercritical Organic Rankine Cycle (ORC) is renowned for higher conversion efficiency than the conventional ORC due to a better thermal match (i.e. reduced irreversibility) presented in the heat exchanger unit. This improved thermal match is a result of the obscured liquid-to-vapor boundary of the organic working fluid at supercritical states. Stand-alone solar thermal power generation and stand-alone geothermal power generation using a supercritical ORC have been widely investigated. However, the power generation capability of a single supercritical ORC using combined solar and geothermal energy has not been examined. This paper thus investigates the hybridisation of solar and geothermal energy in a supercritical ORC to explore the benefit from the potential synergies of such a hybrid platform. Its performances were also compared with those of a subcritical hybrid plant, stand-alone solar and geothermal plants. All simulations and modelling of the power cycles were carried out using process simulation package Aspen HYSYS. The performances of the hybrid plant were then assessed using technical analysis, economic analysis, and the figure of merit analysis. The results of the technical analysis show that thermodynamically, the hybrid plant using a supercritical ORC outperforms the hybrid plant using a subcritical ORC if at least 66% of its exergy input is met by solar energy (i.e. a solar exergy fraction of >66%), namely producing 4–17% more electricity using the same energy resources. Exergy analysis shows that with a solar exergy fraction of more than 66% the exergetic efficiency of the hybrid plant is about 27–34% for the supercritical hybrid plant and 23–32% for the subcritical hybrid plant. The figure of merit analysis indicates that the hybrid plant produces a maximum of 15% (using a subcritical ORC) and 19% (using a supercritical ORC) more annual electricity than the two stand-alone plants. Economically, the hybrid plant using the supercritical ORC has a solar-to-electricity cost of approximately 1.5–3.3% less than those of the subcritical scenario.

Consequence modeling of hazardous accidents in a supercritical biodiesel plant

Biodiesel is going to be one of the most preferable fuels because of fossil fuel sources depletion and rising environmental issues. This type of fuel is produced mainly by transesterification of triacylglycerol compounds such as vegetable oils and animal fats in a catalyzed or non-catalyzed reaction media. Energy, cost and environmental investigations for conventional (catalyzed) and modern (non-catalyzed) methods show that non-catalyzed method in supercritical process conditions is more advantageous but more unsafe because of high pressure and high inventories of flammable materials. Thus, this paper is aimed at identifying and analyzing the severity of process incidents in a supercritical biodiesel plant using consequence modeling and analysis approach. Following this approach, pressurized liquid inventories were identified as the most hazardous sources and subsequently jet fire was identified as the most likely incident in the case of flammable material release. Then, destructive effects of jet fire were simulated for three different leakage sizes from 0.5 to 1.5 inch. The results showed long effect distances, the ranges of which were 61–159m and 70–190m for the structures and humane respectively. According to these results, in the case of jet fire, structures and humane in a long distance around the source of release would be affected. Thus, all human in these areas shall leave the mentioned distances in less than few seconds which seems to be impossible. Also, structures and equipments would be damaged if flame impingement duration lasts more than 2 s. Therefore, sufficient protections should be provided to decrease the level of Jet Fire damage on near structures and personnel. Besides, supercritical biodiesel plants should be designed in a low production capacity in order to decrease the hazardous radios and the duration of feeding the release source in the case of any risk.

Increase of power and efficiency of the 900 MW supercritical power plant through incorporation of the ORC

Abstract The objective of the paper is to analyse thermodynamical and operational parameters of the supercritical power plant with reference conditions as well as following the introduction of the hybrid system incorporating ORC. In ORC the upper heat source is a stream of hot water from the system of heat recovery having temperature of 90 °C, which is additionally aided by heat from the bleeds of the steam turbine. Thermodynamical analysis of the supercritical plant with and without incorporation of ORC was accomplished using computational flow mechanics numerical codes. Investigated were six working fluids such as propane, isobutane, pentane, ethanol, R236ea and R245fa. In the course of calculations determined were primarily the increase of the unit power and efficiency for the reference case and that with the ORC.

Multi-objective optimization of coal-fired power plants using differential evolution

The design trade-offs between thermodynamics and economics for thermal systems can be studied with the aid of multi-objective optimization techniques. The investment costs usually increase with increasing thermodynamic performance of a system. In this paper, an enhanced differential evolution with diversity-preserving and density-adjusting mechanisms, and a newly-proposed algorithm for searching the decision space frontier in a single run were used, to conduct the multi-objective optimization of large-scale, supercritical coal-fired plants. The uncertainties associated with cost functions were discussed by analyzing the sensitivity of the decision space frontier to some significant parameters involved in cost functions. Comparisons made with the aid of an exergoeconomic analysis between the cost minimum designs and a real industrial design demonstrated how the plant improvement was achieved. It is concluded that the cost of electricity could be reduced by a 2–4%, whereas the efficiency could be increased by up to two percentage points. The largest uncertainty is introduced by the temperature-related and reheat-related cost coefficients of the steam generator. More reliable data on the price prediction of future advanced materials should be used to obtain more accurate fronts of the objective space.

New positions for an internal heat exchanger in a CO2 supercritical refrigeration plant. Experimental analysis and energetic evaluation

IHX is probably, one of the most commonly alternative used to improve cooling capacity and COP in a CO2 refrigerating plant working in supercritical conditions. The “classical” position at gas-cooler exit has been analyzed by several authors with positive results. The aim of this work is to compare, from experimental approach, the energetic behavior of a refrigerating plant working with several IHX configurations: gas-cooler exit (classical position), liquid receiver exit, and in both positions at the same time. The energetic behavior includes: cooling capacity, power consumption and COP. Moreover, the discharge temperature reached on each position has been analyzed.From the experimental results, a general improvement in COP and cooling capacity has been observed regardless the position of the IHX. A maximum increment of 13% on COP has been registered working with two IHX at the same time.

Historical Experience Providing Bases for Predicting Corrosion and Stress Corrosion in Emerging Supercritical Water Nuclear Technology: Part 3—Review

This review assesses past experiences from superheated fossil plants, supercritical fossil plants, superheated nuclear plants, and light water reactors from the late 1940s until the present. Data from the development and operation of these plants are directly applicable to supercritical water reactor (SCWR) plants being developed currently. This past work can be applied to the development of current designs in the choice of materials, temperature dependencies, effects of stress, and effects of environments on materials. Some of the past data from light water reactor (LWR) technology can be extrapolated into the present SCWR regimes. The past data are in good agreement among the various previous investigators. These past data are considered with respect to specific components in SCWR: fuel cladding, reactor structurals, reactor vessels, and feed water heaters. Choosing materials for the SCWR applications must recognize that the materials at nominal outlet temperatures are in a dynamic thermal range, i.e., in the nuclear superheat and fossil superheat range, the atomic structures of materials change significantly and change properties such as ductility. It is also possible that compositions and structures of grain boundaries can change, for example, the susceptibility to SCC. The surface temperatures on fuel cladding will be significantly higher than the outlet temperature, and both temperatures will exceed, substantially, the outlet temperatures of present water-cooled plants. Past isothermal data directed toward core structures may not be relevant to the same alloy as fuel cladding. The outlet temperature is useful for considering core structural materials but not for fuel elements, owing to an inevitably high film drop. SCW environments are expected to produce extensive SCC, which differs from past experience. Finally, past data were reanalyzed and additional useful insights were obtained.

Historical Experience Providing Bases for Predicting Corrosion and Stress Corrosion in Emerging Supercritical Water Nuclear Technology: Part 1—Review

This review assesses past experiences from superheated fossil plants, supercritical fossil plants, superheated nuclear plants, and light water reactors from the late 1940s until the present. Data from the development and operation of these plants are directly applicable to supercritical water reactor (SCWR) plants being developed currently. This past work can be applied to the development of current designs in the choice of materials, temperature dependencies, effects of stress, and effects of environments on materials. Some of the past data from light water reactor (LWR) technology can be extrapolated into the present SCWR regimes. The past data are in good agreement among the various previous investigators. These past data are considered with respect to specific components in SCWR: fuel cladding, reactor structurals, reactor vessels, and feedwater heaters. Choosing materials for the SCWR applications must recognize that the materials at nominal outlet temperatures are in a dynamic thermal range, i.e., i...

Comparison of Costs for Natural gas Power Generation with CO2 Capture

In this paper, different systems to capture CO2 in Natural Gas-fired Combined Cycles (NGCC) are compared from technical and economical points of view. Post-combustion capture turns out to be the best technique to remove CO2 from the flue gas at the low CO2 concentrations and the high flow rates characterizing the NGCCs.From a review of the data on costs of capture available in the open literature, it turns out that the Levelized Cost of Electricity (LCOE) and avoided cost presented in the recent Zero Emissions Platform (ZEP) report are the more reliable because they come from a synthesis of the data provided by the manufacturers, operators and researchers and because the Natural Gas (NG) prices considered in the study, ranging from a low value at 4.5 to a high value at 11 €/GJ with a middle value at 8 €/GJ, are currently the most plausible. The costs are provided for 2 types of technology following the demonstration plants, one is NGCC with CO2 post- combustion capture at the early post-demonstration commercial stage (2020-2030), called BASE case, and the other one is an optimization of the first one (2030+), called the OPTI case.The results show how high the impact of the NG price is on the LCOE and capture costs. As an illustration, LCOE of NGCC with post-combustion capture nearly doubles, from 65 €/MWh for a low price of NG (4.5 €/GJ) up to 115 €/MWh for a high price (11 €/GJ) at the 2030 horizon (OPTI plant). In terms of avoidance cost, it is nearly twice as much for NG in NGCC as for coal in supercritical steam plants (95 €/t vs. 49).The beak-even CO2 price is obtained when the European Union Allowance (EUA) price is around 80 €/t for the optimized NGCC case (from 2030 on) and around 110€/t CO2 for the BASE case (2020), both with CO2 capture. Until these CO2 prices are reached, it will be cheaper to build new natural gas-fired plants without Carbon dioxide Capture and Storage (CCS) and pay for EUAs, than to build new ones or retrofit existing ones with CCS. Alternative NG fuelled systems based on pre-combustion capture on the one hand and on oxy-fuel combustion on the other hand are reviewed here but on the basis of their performance and costs are currently not threatening the ascendency of NGCCs with post-combustion capture. However, these NG based systems are still immature and require new developments and designs so that the costs available in the literature today are more projections than real costs. Only one option, SOFC/GT, looks very attractive due to its high performance but no trustable data on costs are available to date.

Qualification of Ni-Based Alloys for Advanced Ultra Supercritical Plants

For the realization of advanced ultra-supercritical plant operating at service temperatures of up to 720 °C plants Ni-based alloys are indispensable. This paper describes the on-going investigations on the qualification of several Ni-based alloys such as Alloy 617, Alloy 263 and Alloy 740 within the framework of the German state funded R&D initiative COORETEC. For safe design and reliable operation of components the requirements of the European Pressure Equipment Directive (PED) have to be fulfilled. Experimental work was done in order to determine the relevant material characteristics, such as long-term creep strength values for the design of critical components. Also new design methods based on numerical calculation of the creep behaviour by using a constitutive creep equation including a damage parameter are required to make full use of the strength potential but also taking into account their specific stress-strain relaxation behaviour. Investigation of the microstructure by optical microscopy (OM), scanning electron microscopy (SEM) and transmission electron microscopy (TEM) of the as delivered and crept state show the changes in precipitation depending on time and temperature.

Historical Experience Providing Bases for Predicting Corrosion and Stress Corrosion in Emerging Supercritical Water Nuclear Technology—Part 2: Review

This review assesses past experiences from superheated fossil plants, supercritical fossil plants, superheated nuclear plants, and light water reactors from the late 1940s until the present. Data from the development and operation of these plants are directly applicable to supercritical water reactor (SCWR) plants being developed currently. This past work can be applied to the development of current designs in the choice of materials, temperature dependencies, effects of stress, and effects of environments on materials. Some of the past data from light water reactor (LWR) technology can be extrapolated into the present SCWR regimes. The past data are in good agreement among the various previous investigators. These past data are considered with respect to specific components in SCWR: fuel cladding, reactor structurals, reactor vessels, and feed water heaters. Choosing materials for the SCWR applications must recognize that the materials at nominal outlet temperatures are in a dynamic thermal range, i.e., in the nuclear superheat and fossil superheat range, the atomic structures of materials change significantly and change properties such as ductility. It is also possible that compositions and structures of grain boundaries can change, for example, the susceptibility to SCC. The surface temperatures on fuel cladding will be significantly higher than the outlet temperature, and both temperatures will exceed, substantially, the outlet temperatures of present water-cooled plants. Past isothermal data directed toward core structures may not be relevant to the same alloy as fuel cladding. The outlet temperature is useful for considering core structural materials but not for fuel elements, owing to an inevitably high film drop. SCW environments are expected to produce extensive SCC, which differs from past experience. Finally, past data were reanalyzed and additional useful insights were obtained.

Thermoeconomic cost analysis of a 600 MWe oxy-combustion pulverized-coal-fired power plant

Oxy-combustion technology, through adding a cryogenic air separation unit process and a flue gas treatment unit process to a conventional combustion process, has been rapidly developed because it is considered as a feasible choice to capture CO2 from power plants for sequestration. To reach a comprehensive understanding of the thermodynamic and economic characteristics of the oxy-combustion process, a detailed thermoeconomic cost analysis of a 600MWe oxy-combustion pulverized-coal-fired power plant was carried out. Based on the detailed results of exergy analysis and the latest data of investment cost, the results of exergy cost and thermoeconomic cost were obtained. It is found that, in comparison to the corresponding conventional supercritical plant with the same gross output (600MWe), the additional power consumption in the oxy-combustion system increases the unit exergy costs (or unit thermoeconomic costs) of products for about 10%. On the other hand, the additional monetary cost, including investment cost, interest, and operation and maintenance cost, in the oxy-combustion system increases the unit thermoeconomic costs of products for nearly another 10%. The relation between the unit thermoeconomic cost change and the unit exergy cost change in the oxy-combustion system comparing to the conventional system was established. Moreover, in this paper, a new decomposition method for exergy cost was proposed to explore the formation mechanism of the exergy cost, furthermore, the thermoeconomic cost. The unit exergy cost was decomposed into three parts: fuel, exergy destruction, and negentropy. Meanwhile, the reasonable unit exergy costs of exergy destructions happened in the system can be defined. It is found that the exergy destruction part is the most important factor that affects the unit exergy costs of products for these components in the same model (such as the boiler model).

Materials for ultra-supercritical power plants

This paper describes the status of the art of the materials available on the market for the current Best Available Technologies for design and construction of the Ultra-SuperCritical (USC) Pulverised Coal Steam Power Plants to produce electricity. The new USC plants build in the last 10 years are able to reach 42–48% efficiency respect to 30% of the old subcritical (SubC) or 40–42% of the supercritical plants. This improvement is mainly due to the development of new materials in the years 1980–1990 able to work in more severe condition of temperature, pressure and aggressive environment and the consequent new design of boiler and steam turbine. The new materials developed are low chromium ferritic/bainitic, high chromium martensitic and the austenitic steels used in the different area of the power plants for manufacture of tubes and pipes, forged and cast components. These are joined by different welding technologies and materials also developed as function of materials and sizes of components.

Evaluation of cost reduction potential for a coal based polygeneration system with CO2 capture

The coal based polygeneration with CO2 capture (PG + CC) technology is expected as one of the possible options to mitigate CO2 emissions with low cost and low energy. This work assesses the cost reduction potential of PG + CC technology based on learning curve method, and finds out what factors and how they influence the cost curve.Results show that the unit investment of PG + CC can decrease to around 600–900$/kW from current 1500$/kW by means of capacity increment, technology further localization and plant efficiency upgrade. Localization and plant efficiency upgrade will play an important role in PG + CC cost reduction. 45%∼55% of the unit investment reduction originates from the capacity increment, 20%∼35% from technology localization, and 10%∼20% from plant efficiency upgrade.Compared with IGCC technology with CO2 capture (IGCC + CC), the unit investment of PG + CC is 25%∼30% lower. Compared with coal-pulverized supercritical plant with CO2 capture (PC + CC), in short term PG + CC is less economically competitive；In medium term, when the total installed capacity reaches several to ten GWs, the unit investment of PG + CC technology can compete with that of PC + CC and will be lower afterwards；In long term, the PG + CC technology will be more economically competitive than PC + CC. Moreover, PG + CC is more energy efficient than the other two technologies. The results indicate that the coal based PG + CC is more acceptable for China and may act as a significant part in CO2 capture technologies.

Review of factors affecting steam oxidation testing

Thermal efficiency of current 600°C plant is typically around 45 –46%, this can be raised to over 50% by increasing the operating temperature to 650°C with future goals of 700 and 750°C Advanced Super Critical plant. This increase in operating conditions places increasingly higher demands on conventional materials both in terms of creep strength and corrosion. Recent experience within a five-year programme of collaborative work carried out under the auspices of the UK–US Memorandum of Understanding (MOU) and the associated Implementing Agreement for Fossil Energy Research and Technology Development, has shown that the generation of such data is not as straight forward as one might expect. It has been shown through extensive test programmes on the same materials that different results and alloy behaviour can be found, which are caused by relatively small differences in the test procedure.In this paper, steam oxidation will be considered, with examples presented and discussed showing the variation in oxidation rates that can be found between different laboratories and even within controlled intercomparisons. The main experimental factors that are believed to affect the alloy behaviour will be introduced and examples presented to illustrate the effect on the oxidation rate and scale morphology.

ANN based optimization of supercritical ORC-Binary geothermal power plant: Simav case study

Abstract Artificial neural network is a new tool, which works rapidly for decision making and modeling of the processes within the expertise. Therefore, ANN can be a solution for the design and optimization of complex power cycles, such as ORC-Binary. In the present study, the back-propagation learning algorithm with three different variants, namely Levenberg–Marguardt (LM), Pola-Ribiere Conjugate Gradient (CGP), and Scaled Conjugate Gradient (SCG) were used in the network to find the best approach. The most suitable algorithms found were LM 16 for s1 type cycle and LM 14 for s2 type cycle. The Organic Rankine Cycle (ORC) uses organic fluids as a working fluids and this process allows the use of low temperature heat sources and offers an advantageous efficiency in small-scale concepts. The most profitable cycle is obtained with a benefit of 124.88 million US$ from s1 type supercritical ORC-Binary plant with an installed capacity of 64.2 MW when the working fluid is R744 and the design parameters of T 1b , T 2a and P 2a are set to 80 °C, 130 °C and 12 MPa, respectively.

Approach and application of life cycle screening in early phases of process design: case study of supercritical water gasification

Process design can be influenced most in the early phases. Here, screening methods play a major role, as they reduce the complexity of a system studied by making a pre-selection from a set of alternatives available. The remaining alternatives can be analyzed in more detail in the subsequent design process, which increases design efficiency. The present paper focuses on a multi-stage screening approach for use in the early process development phase in particular. This approach is based on the use of non-compensatory decision support methods that are transferred to life cycle assessment. It may be divided into a first stage, in which the decision matrix used is developed on the basis of decision analysis principles, and a second stage, in which the decision matrix developed is further processed using non-compensatory decision support methods. An example of such a method is the pareto-dominance analysis applied here. The approach proposed is validated by application to the process of biomass gasification in supercritical water, which is being developed at the moment. Here, screening is performed to identify those life cycles, the potential environmental impacts of which contribute most to the total impacts. Attributes are selected in line with the requirement of a simple, but still sufficient modeling of these environmental impacts. By pareto-dominance analysis, emissions from the gasification of sewage sludge, the pre-chain of natural gas production, and from the construction of the supercritical gasification plant are identified to dominate over the remaining life cycles studied. Apart from the predominating alternatives, it is of particular importance to know the dominated alternatives. Due to their small shares in the result, no or only a small expenditure is needed to identify improvement potentials of these alternatives.

Interactions between energy security and climate change: A focus on developing countries

We briefly consider the tensions between climate change and energy security policy imperatives, and highlight some concepts that may bring additional clarity to decision-making at the nexus of the two areas. We focus on developing countries and use the case of the Medupi supercritical coal plant in South Africa. The justification for the plant's construction stemmed from an Integrated Resource Planning process informed by South Africa's national utility. Often, as in the case of South Africa, there are tensions not easily captured in quantitative algorithms between, inter alia, a lack of access to electricity by millions of people (and associated welfare losses) and greenhouse gas emissions from electricity generation. It is difficult to identify any formal processes that have prioritised climate change considerations over those of energy access. Thus, it becomes imperative to have a clear understanding of the consequences of this reality when considering power system expansion. We find that the processes often employed do not provide an entirely satisfactory precedent for future planning analyses, and the justifications do not adequately reflect the complexity of the decision space. Finally, we highlight some options by which these tools might be enhanced in areas including explicit and formal consideration of risk.

Using auxiliary gas power for CCS energy needs in retrofitted coal power plants

Adding post-combustion capture technology to existing coal-fired power plants is being considered as a near-term option for mitigating CO2 emissions. To supply the thermal energy needed for CO2 capture, much of the literature proposes thermal integration of the existing coal plant’s steam cycle with the capture process’ stripper reboiler. This paper examines the option of using an auxiliary natural gas turbine plant to meet the energetic demands of carbon capture and compression. Three different auxiliary plant technologies were compared to integration for 90% capture from an existing, 500 MW supercritical coal plant. CO2 capture (via a monoethylamine (MEA) absorption process) and compression is simulated using Aspen Plus. Thermoflow software is used to simulate three gas plant technologies. In some circumstances, it is found that using an auxiliary natural gas turbine may make retrofits more attractive compared to using thermal integration. The most important factors affecting desirability of the auxiliary plant retrofit are the cost of natural gas, the full cost of integration, and the potential for sale of excess electricity.