Academic literature on the topic 'Solid recovered fuel'

This paper deals with the state and perspectives of bioenergy development in the context of exploiting the potential of available natural resources. We analyse the economic benefits of transitioning to alternative biofuel within the research task in cooperation with the Vojany black coal power plant. Within the applied methodology, a non-parametric data envelopment analysis method was used to confirm the most economically efficient types of fuels used in the combustion process. The assumption of fuel efficiency was confirmed by testing fuel combustion combinations directly in the power plant. The transition to 100% combustion of solid recovered fuel creates the potential for sustainable production of the analysed power plant and compliance with the current emission values of basic pollutants and new stricter limits, which will be binding in the EU from August 2021. The proposed solutions were analysed by Monte Carlo simulation. An estimate of the economic results achieved by the power plant was simulated, assuming a complete transition to solid recovered fuel. The results of the study support the feasibility of creating a circular waste management market, with the Vojany black coal power plant as the largest user of solid recovered fuel in Slovakia and abroad.

The importance of waste energy is increasing with increasing emphasis on carbon neutrality. Solid recovered fuels (SRFs) are manufactured to recycle waste into fuel form and can replace fossil fuels by recovering the heat generated by using them. This study calculated the manufacturing and energy recovery efficiency of SRF facilities. The manufacturing efficiency was calculated as the amount of SRFs manufactured compared to the amount of input waste. The energy recovery efficiency was calculated using the R1 method, which is applied to incineration heat energy recovery facilities. The manufacturing efficiency was 69.5%, which varies depending on the combustible material content of input waste. The energy recovery efficiency was 85.4%, which satisfied Korean energy recovery efficiency facility standards. Our study highlights the manufacturing and use of SRFs as one of the options for recycling waste and its potential as a substitute for fossil fuels.

This paper compares conventional and microwave hydrothermal carbonization (HTC) of human biowaste (HBW) at 160 °C, 180 °C and 200 °C as a potential technology to recover valuable carbonaceous solid fuel char and organic-rich liquor. Also discussed are the influence of HTC heating methods and temperature on HBW processing conversion into solid fuel char, i.e. yield and post-HTC management, dewaterability rates, particle size distribution and the carbon and energy properties of solid fuel char. While HTC temperatures influenced all parameters investigated, especially yield and properties of end products recovered, heating source effects were noticeable on dewatering rates, char particle sizes and HBW processing/end product recovery rate and, by extension, energy consumed. The microwave process was found to be more efficient for dewatering processed HBW and for char recovery, consuming half the energy used by the conventional HTC method despite the similarity in yields, carbon and energy properties of the recovered char. However, both processes reliably overcame the heterogeneity of HBW, converting them into non-foul end products, which were easily dewatered at <3 seconds/g total solids (TS) (c.f. 50.3 seconds/g TS for a raw sample) to recover energy-densified chars of ≈17 MJ/kg calorific value and up to 1.4 g/l of ammonia concentration in recovered liquor.

According to the 1999/31 EC Directive, municipal solid waste should not be disposed for landfill from 2005. In this way, more environmental friendly waste management options are promoted towards the volume reduction and limitation of negative consequences. In this context, attention is focused on the utilization of solid recovered fuels derived from the waste treatment as coal substitute in large-scale power plants. Such activities are realized within an EU-funded project RECOFUEL, in which the solid recovered fuels co-combustion with brown coal is demonstrated in two commercial-scale PF-boilers at R WE Power's power plant site in Weisweiler, Germany. During testing the thermal share of solid recovered fuels in the overall thermal input was adjusted to some 2%, resulting into a feeding rate of about 2 x 12.5 tons per hour. NTUA-LSB in cooperation with IVD-University of Stuttgart, Germany, is responsible for the boiler measurements and the characterization of boilers operational behavior. Among the main activities are the technology transfer of co-combustion practice in the Balkan countries and the perspectives of its future application in the Greek region, with respect to the special characteristics of the Greek brown coal and municipal solid waste. Co-combustion tests of brown coal and solid recovered fuels, that have been taken place up to now, have been successfully performed and the strict European emission limits are kept. The waste quantities in Greece that can be utilized are estimated in 200,000 Mg/year while their utilization in existing thermal plants is expected to bring savings of 3% lignite use and avoidance of up to 200,000 Mg CO2 per year.

This thesis is concerned with the production of solid recovered fuel (SRF) from municipal solid waste using mechanical biological treatment (MBT) plants. It describes the first in-depth analysis of a UK MBT plant and addresses the fundamental research question: are MBT plants and their unit operations optimised to produce high quality SRF in the UK? A critical review of the process science and engineering of MBT provides timely insights into the quality management and standardisation of SRF use in Europe. Quantitative fuel property data for European SRFs are collated and analysed statistically in a detailed examination of the fuel quality achievable from MBT-derived SRF. The experimental research herein applies statistical sampling, analytical characterisation and materials flow analysis to a new generation, fully operational SRF-producing MBT plant. To the author’s knowledge, this is the first detailed analysis of this kind for a UK plant. Individual process flows from mechanically processed waste are characterised using a series of fuel properties in line with the European product standards for SRF, and confidence limits in these properties quantified. New data on SRF quality, including biogenic content, is provided. In seeking understand the variability in waste heterogeneity and its impact on SRF production in an MBT plant, material flow analysis is applied across the MBT flowsheet to compute transfer coefficients for individual unit operations. This provides a basis for critically evaluating the performance of this specific MBT and the extent to which is it optimised for SRF production. Cont/d.

The waste treatment, particularly the thermal treatment of waste has changed fundamentally in the last 20 years, i.e. from facilities solely dedicated to the thermal treatment of waste to facilities, which in addition to that ensure the safe plant operation and fulfill very ambitious criteria regarding emission reduction, resource recovery and energy efficiency as well. Therefore this contributes to the economic use of raw materials and due to the energy recovered from waste also to the energy provision. The development described had the consequence that waste and solid recovered fuels (SRF) has to be evaluated based on fuel criteria as well. Fossil fuels – coal, crude oil, natural gas etc. have been extensively investigated due to their application in plants for energy conversion and also due to their use in the primary industry. Thereby depending on the respective processes, criteria on fuel technical properties can be derived. The methods for engineering analysis of regular fuels (fossil fuels) can be transferred only partially to SRF. For this reason methods are being developed or adapted to current analytical methods for the characterization of SRF. In this paper the possibilities of the energetic utilization of SRF and the characterization of SRF before and during the energetic utilization will be discussed.

Solid Oxide Fuel Cells (SOFC) as the heat source for a heat engine power cycle can greatly increase the overall efficiency. The maximum efficiency is limited in at least the following ways. All thermal heat engine power cycles are limited by the Carnot efficiency which is a function of the hot and cold reservoirs the cycle operates between. Another irreversibility that limits the maximum efficiency of a fossil fuel cycle is the combustion reaction. In a boiler or combustion chamber, the chemical reaction of combustion happens spontaneously, meaning that the reaction happens without being used to generate power. A fuel cell decreases this irreversibility because it generates work as the combustion reaction happens. A SOFC can do this without an expensive catalyst due to the higher operating temperature. The power generated by the fuel cell can be added to the power generated by the thermal power cycle operating from the exhaust of the SOFC. The total work generated would be more than the system would have generated from just the heat engine resulting in a higher overall efficiency for the cycle. A SOFC and a recovery power cycle was simulated in Engineering Equation Solver (EES) to solve for ideal operating conditions. The fuel cell and gas turbine system had a net power output of 136 MW and had an efficiency of 60.84%, assuming the fuel cell had an 85% fuel utilization.

La gasificació és una tecnologia prometedora per l’aprofitament energètic de biomassa i residus, ja que permet convertir els combustibles sòlids en un gas de síntesi (syngas) amb diverses aplicacions. No obstant això, algunes limitacions encara impedeixen la completa implementació d’aquesta tecnologia a escala industrial, en particular per a la producció de combustibles líquids a partir del procés Fischer-Tropsch (FT). Els principals inconvenients estan relacionats amb la qualitat del syngas, per exemple una baixa relació H2/CO i la presència d’impureses (tar i contaminants menors), i depenen de la naturalesa del material i de les condicions d’operació del procés de gasificació. Aquesta tesi es centra en la millora de la qualitat del syngas de gasificació de biomassa i combustibles sòlids recuperats (CSRs) per a la producció de combustibles líquids. El treball es divideix en dos parts principals. La primera part consisteix en estudis experimentals de gasificació de biomassa i CSRs en un reactor de llit fluïditzat a escala de laboratori per tal d’analitzar la influència de les condicions d’operació (temperatura, agents de gasificació, etc.) en el rendiment del procés i la composició del gas. Ja que els CSRs contenen més quantitats de precursors de contaminants que la biomassa, es va desenvolupar un mètode per tal de determinar la concentració de HCl, H2S, HCN i NH3 en el syngas mitjançant la potenciometria d’ió-selectiu. També, es proposa l’aplicació d’un pretractament tèrmic (torrefacció) als materials de gasificació com un mètode per tal de millorar les propietats dels materials i disminuir l’emissió de contaminants en el syngas. Per últim, la segona part d’aquest treball consisteix en un estudi tecno-econòmic per estimar els costos d’inversió i d’operació de plantes de combustibles líquids FT a partir de la gasificació de biomassa i residus, partint dels resultats obtinguts experimentalment.<br>La gasificación es una tecnología prometedora para el aprovechamiento energético de biomasa y residuos ya que permite convertir los combustibles sólidos en un gas de síntesis (syngas) con múltiples aplicaciones. Sin embargo, ciertas limitaciones todavía impiden la completa implementación de esta tecnología a escala industrial, en particular para la producción de combustibles líquidos a partir del proceso Fischer Tropsch (FT). Los principales inconvenientes están relacionados con la calidad del syngas, por ejemplo una baja relación H2/CO y la presencia de impurezas (tar y contaminantes menores), y dependen de la naturaleza del material y de las condiciones de operación del proceso de gasificación. Esta tesis se centra en la mejora de la calidad del syngas de gasificación de biomasa y combustibles sólidos recuperados (CSRs) para la producción de combustibles líquidos. El trabajo se divide en dos partes principales. La primera parte consiste en estudios experimentales de gasificación de biomasa y CSRs en un reactor de lecho fluidizado a escala de laboratorio para evaluar la influencia de las condiciones de operación (temperatura, materiales de lecho, agentes de gasificación, etc.) en el rendimiento del proceso y la composición del gas. Debido a que los CSRs contienen mayores cantidades de precursores de contaminantes que la biomasa, se ha desarrollado un método para determinar la concentración de HCl, H2S, HCN y NH3 en el syngas mediante potenciometría de ion selectivo. Además, se propone la aplicación de un pretratamiento térmico (torrefacción) a los materiales de gasificación como un método para mejorar las propiedades de los materiales y disminuir la emisión de contaminantes en el syngas. Por último, la segunda parte consiste en un estudio tecno-económico para estimar los costes de inversión y de operación de plantas de combustibles líquidos FT a partir de la gasificación de biomasa y residuos, partiendo de los resultados obtenidos experimentalmente.<br>Gasification is a promising technology for energy exploitation of biomass and waste, converting carbonaceous fuels into a synthesis gas (syngas) with multiple applications. However, technical obstacles hinder the full implementation of this technology at industrial scale, particularly for the production of liquid fuels through Fischer-Tropsch (FT) synthesis. Those challenges are mainly related to the syngas quality, such as a low H2/CO ratio and the presence of impurities (tar and minor contaminants), strongly influenced by the nature of the feedstock and the operating conditions of the gasification process. This thesis focuses on the improvement of the syngas quality from gasification of biomass and solid recovered fuels (SRFs) aiming to produce liquid fuels. The present work is divided in two main blocks. The first block corresponds to biomass and SRFs gasification experiments in a lab-scale fluidized bed reactor in order to study the influence of key operating conditions (temperature, bed materials, gasification agents, etc.) on the gasification performance and gas composition. Since SRF materials contain higher amounts of contaminants precursors than biomass, a method to assess the concentration of HCl, H2S, HCN and NH3 in the syngas by means of ion-selective potentiometry was developed. The application of a thermal pretreatment (torrefaction) to the gasification feedstocks is proposed as a way to upgrade the feedstock properties and abate the release of contaminants in the syngas. The second part of this work consists in a techno-economic analysis that estimates capital and production costs of FT liquid fuel plants based on biomass and waste gasification, using as input the experimental results.

Thesis (MTech (Chemical Engineering))--Cape Peninsula University of Technology, 2016.<br>Landfill gases, principally methane, CH4 are produced from the decomposition of the municipal solid wastes deposited on landfill sites. These gases can be captured and converted into usable energy or electricity which will assist in addressing energy needs of South Africa. Its capture also reduces the problems associated with greenhouse gases. The aim of this study is to estimate gases that can be produced from the Bellville landfill site in Cape Town. The landfill gas capacity was estimated using Intergovernmental Panel on Climate Change (IPCC) model. The IPCC model showed that 48 447m3/year of landfill gas capacity was determined only in 2013. The LFGTE process plant is designed in a manner of purifying landfill gas, which at the end methane gets up being the only gas combusted. As a matter of fact 14 544kg/year of gases which consists mainly methane gets combusted. The average energy that can be produced based on the generated landfill gas capacity (methane gas) is 1,004MWh/year. This translates to R1. 05million per year at Eskom’s current tariff of R2.86 /kWh) including sales from CO2 which is a by-product from the designed process plant. A LFGTE process plant has been developed from the gathered information on landfill gas capacity and the amount of energy that can be generated from the gas. In order, to start-up this project the total fixed capital costs of this project required amounted up to R2.5 million. On the other hand, the project made a profit amounted to R3.9million, the Net profit summed up to R1. 3million and the payback time of Landfill Gas ToEnergy (LFGTE) project is 4years.The break-even of the project is on second year of the plant’s operation. The maximum profit that this project can generate is around R1. 1million. The life span of the plant is nine years. Aspen plus indicated that about 87% of pure methane was separated from CO2 and H2S for combustion at theabsorption gas outletstream. I would suggest this project to be done because it is profitable when by-products such as CO2 sales add to the project’s revenues.

Thermal treatment is recognised as a valid option within the waste management hierarchy for the recovery of the energy content of waste. Recent developments in the field are signposted from emergent technologies and the standardisation of solid recovered fuels. This work comparatively examines the fluidized bed combustion and gasification of a novel material; East London’s solid recovered fuel. Emphasis is given on the characterisation of the solid residues produced from the two thermal treatment techniques and chlorine partitioning, in particular. Chlorine mass balances are studied under steady state conditions for combustion and gasification. Furthermore, trace metals content, chlorobenzenes, major elements, crystalline structures, and leaching behaviours are compared in the two residues types. For the characterisation of these residues a series of analytical methods have been applied and compared for their efficiencies. Results indicate that gasification produces 5-6 times less HCI than combustion. Furthermore, gasification residues retain higher amounts of CI and in less water soluble forms. However, gasification residues have 3-8 times higher organochlorides load, expressed chlorobenzenes. This work generates novel data on the comparative characterisation of waste thermal treatment residues. These data contribute towards the technical confidence for further utilisation of solid recovered fuels, and the knowledge over the residues’ properties.

This thesis covers two main areas of investigation, the production and recovery of process dusts formed in the steelmaking industry, and secondly the study of the utilisation of coals for injection in a blast furnace and during co-firing with biomass in a utility boiler. These are linked by an overall aim to research the environmental and economic sustainability of industrial processes through increased process efficiency, decreased environmental impacts, and increased recovery of waste. It comprises a summary of the research contribution from six first-author peer reviewed journal publications and nine supplementary contributions for the submission of a PhD by published works. Process dust research was carried out on a 300t vessel requiring the development of a novel industrial scale isokinetic sampling methodology, capable of sampling frequently enough to measure and analyse mass flow profiles and zinc mass contamination profiles at a higher level of detail than in prior research. A new understanding of the impact of inprocess iron ore additions and waste oxide additions were correlated with additional dust and zinc mass peaks. This methodology was also used to prove that a new process change involving a galvanised scrap holding stage could be applied to successfully reduce the zinc contamination. Research into a modified hydrometallurgical leaching method for blast furnace dust gave high zinc extraction, but with low iron extraction, by the novel utilisation of the substituent group effect of carboxylic acid leaching. Further research also identified that improvements in the zinc extraction selectivity could be achieved using a non-aqueous solvent to utilise the Lewis acid effect. In terms of solid fuel utilisation, factors such as the physical properties, cost, and availability result in end users blending coals to meet their needs. The use of higher volatile matter coals was found to benefit blends with low volatile coal in the context of the blast furnace, but research conducted on a 500MW utility boiler showed that carbon monoxide and dust levels increase. Although grinding coals to a pulverised specification has been proved to benefit utilisation, new findings show that the additional grinding alters the surface chemistry and reactivity of many coals and was related to reduced burnouts compared to some larger particle size specifications. Research on industrial processes is challenging, but these papers aim to address sustainability issues in terms of the efficient use and recovery of materials.

AbstractAs a new concept, oxygen carrier aided combustion (OCAC) technology proposed in 2013 by Chalmers University of Technology’s group, can alleviate the problem of uneven distribution of oxygen in the reactors. In the past 10 years,various research institutions, including Chalmers University of Technology, University of Cambridge, Tsinghua University, Friedrich-Alexander University and University of Nottingham, have conducted a series of studies on OCAC technology. It is worth mentioning that Chalmers University of Technology has complied with most of these studies from laboratory to industry scales. In particular, they carried out a serious of semi-industrial scale experiments in the 12 MWthCFB boiler, which is well-known research boiler. OCAC technology is comprehensively introduced from six aspects: combustion characteristics, NOx/SOx emission, ash-related issues, aging of oxygen carrier, oxygen carrier recovery and physicochemical characteristics of oxygen carrier. In this chapter, allsummarized studies were performed under traditional air-combustion conditions without much consideration of CO2 capture.

Thermoelectric generator (TEG) converts waste heat energy from automobiles into valuable electrical power and has no moving parts compared to conventional thermoelectric motors. The functioning of TEG is dependent on the design and the material used. TEGs are classified as small and medium power outputs. Small power outputs are in the range between 5 μW to 1W, and high power outputs are higher than 1W in a TEG. Thermoelectric power generators offer fast, economical storage methods for wearable and mobile applications. Macro heat waste application is recovered through in-house, industrial and solid waste. Moreover, an immense amount of waste fuel, such as recycling and power plants, is emitted from the industry; this can be utilized in a useful manner by TEGs. This chapter discusses the TEG study of the fundamental operating principles, TEG products, micro applications and energy generation techniques.

Increased consumption and energy security issues have led many developed and developing countries to seek methods to produce alternative fuels. Biodiesel is one such high-density alternative fuel that can increase the longevity of transportation fuels. Biodiesel can be produced from a wide range of feedstock using simple process schemes. In the past, edible oils were used as feedstock for biodiesel fuel production; however, use of non-traditional feed stock like waste cooking oil, non-edible oils, animal fats, and algae can make biodiesel production a sustainable process. The high free fatty acids content in the feedstock, longer reaction rates, high energy consumption, and the catalysts used in the conversion process pose some limitations for current biodiesel production. These limitations can be addressed by developing novel process techniques such as microwaves and ultrasound and by developing non-catalytic transesterification methods. Enhancing byproduct recovery seems to be an important strategy to improve the energy footprint and economics of current biodiesel production.

Water recovery and recycling are key technologies for fuel cell power systems. This paper describes technology to recover and recycle water using a compact, efficient condenser to separate water from a fuel cell exhaust stream. The condenser uses an innovative, micromachined condensing surface to achieve very high condensation mass flux and enable very high water recovery efficiency from a compact system. The condenser is sized for a 5 kWe, solid oxide fuel cell (SOFC) power system, but can easily be scaled up for higher power systems. We demonstrated operation of the condenser using an input stream that simulated the exhaust from an SOFC power system. Our device condensed and recovered 97–99% of the water in the input stream while consuming very little power (about 50 W).

This paper presents results from an investigation concerning load-induced degradation, recovery, and control of solid oxide fuel cells (SOFCs). In this study, commercially available SOFCs were subject to extended over-current conditions, followed by periods of open-circuit operation. During times of current loading, degradation was observed in the cells’ electrical performance through polarization and electrochemical impedance spectroscopy (EIS) measurements. These measurements showed an increase in the polarization curve’s ohmic region slope, i.e. large-signal resistance, as well as an increase in the cell’s small-signal low-frequency impedance. The degradation was temporary however, as the electrical performance recovered during times of open-circuit operation. These results, attributed to electrochemically-induced oxidation and reduction of nickel in the anode, suggest the degradation phenomenon is controllable via the electrical terminals. As such, an additional test was performed on an SOFC powering a pulse-width modulated load, with the load’s duty-cycle negatively proportional to the cell’s large-signal resistance. Polarization and EIS measurements taken during this test showed that despite the controlled load, degradation occurred throughout the test. However, post-test scanning electron microscope images revealed cracks in the cell’s cathode along the boundary between the active and bulk layers. This type of cracking was not observed in the original degradation and recovery tests, suggesting that the degradation observed in the controlled load test was irreversible and caused by a separate phenomenon.

According to the waste management hierarchy published by the U.S. EPA, waste reduction and reuse are the most preferred modes of waste management, followed by recycling, energy recovery and lastly disposal. As many communities in the U.S. work towards sustainable waste management practices, recycling tends to be a cost-effective and common solution for handling municipal solid waste. With the introduction of single-stream recycling and automated materials recovery facilities (MRFs), where commingled recyclables are sorted into various commodity streams for sale to recycling facilities, recycling rates have steadily climbed in recent years. Despite increasing total recycling rates, contamination and diminishing returns for higher recovery ratios causes MRFs to landfill 5–25% of the incoming recycling stream as residue. This residue stream is composed primarily of plastics and fiber, both of which have high energy content that could be recovered instead of buried in a landfill. Plastics in particular are reported to have heat contents similar to fossil fuels, making energy recovery a viable end-of-life pathway. Sorting, shredding and densifying the residue stream to form solid recovered fuel (SRF) pellets for use as an alternative fuel yields energy recovery, displaced fossil fuels and landfill avoidance, moving more disposed refuse up the waste management hierarchy. Previous studies have shown that plastic, paper, and plastic-paper mixes are well suited for conversion to SRF and combustion for energy production. However, these studies focused on relatively homogenous and predictable material streams. MRF residue is not homogenous and has only a moderate degree of predictability, and thus poses several technical challenges for conversion to SRF and for straightforward energy and emissions analysis. This research seeks to understand the energetic and environmental tradeoffs associated with converting MRF residue into SRF for co-firing in pulverized coal power plants. A technical analysis is presented that compares a residue-to-SRF scenario to a residue-to-landfill scenario to estimate non-obvious energy and emissions tradeoffs associated with this alternative end-of-life scenario for MRF residue. Sensitivity to key assumptions was analyzed by considering facility proximity, landfill gas capture efficiency, conversion ratio of residue to SRF and the mass of residue used. The results of this study indicate that the use of MRF residue derived SRF in coal fired steam-electricity power plants realizes meaningful reductions of emissions, primary energy consumption, coal use and landfill deposition.

Abstract Thermochemical redox cycles are a promising route for the production of solar fuels. In this paper we present a novel Reactor Train system for efficient conversion of solar thermal energy to hydrogen. This system is capable of recovering thermal energy from redox materials, which is necessary for achieving high efficiency, but has been difficult to realize in practice. The Reactor Train System overcomes technical challenges of high temperature thermochemical reactors like solid conveying and sealing, while enabling continuous, round-the-clock fuel production and incorporating efficient gas transfer processes and thermal energy storage. The Reactor Train is comprised of several identical reactors arranged in a closed loop and cycling between reduction and oxidation steps. In between these steps, the reactors undergo solid heat recovery in a radiative counterflow heat exchanger. We report a heat recovery effectiveness of 75–82% with a train consisting of 56 reactors and a cycle time of 84 minutes. With ceria as the redox material, 23% of the high temperature thermal energy input is converted to hydrogen, while 49% is recovered as intermediate-temperature heat at 750 °C.

Nuclear energy systems are necessary to assure sufficient energy resources without harming the environment. Fast reactor (FR) systems are especially important taking into account the limited uranium resources and the nuclear sustainability. As the FR system is still under development, FR deployment start-time and rate are unclear. On the other hand, it is desirable to reduce light water reactor (LWR) spent fuel due to the difficulties of storage and disposal (retrievable) site determination. Reprocessing is one of the effective methods to reduce LWR spent fuel but the recovery and long-term storage of plutonium, even with uranium, is undesirable for the aspect of proliferation resistance. The authors propose the new system named Flexible Fuel Cycle Initiative (FFCI), which recovers only uranium (∼90%) from LWR spent fuel and stores the residual material (∼5% U, ∼1% Pu, ∼4% other nuclides) for the future FR deployment. Residual material named recycle material (RM) is suitable for FR fresh fuel preparation due to its high Pu concentration and similar Pu/U ratio to FR core fuel, and for proliferation resistance due to its high concentrations of fission products (FP) and minor actinides (MA). The volume of RM is about 1/10 of that of LWR spent fuel. However RM needs sufficient heat removal, radiation shielding and criticality safety. After the FR development is finished and several years before the commercial FR deployment start-time, Pu and U will be recovered from the RM that might be stored liquid or solid state. Many well known methods can be applied for U recovery such as solvent extraction, crystallization, precipitation, electro refining, and fluoride volatilization. As recovered U has slightly higher U-235 concentration than natural U, its re-enrichment and recycling in LWRs seems to be effective for ultimate utilization of nuclear resources. In this case fluoride volatility U recovery method is most preferable because the product is UF6 that is the supply material for enrichment. Quantitative evaluations have been carried out for several fuel cycle systems including FFCI with parameters such as spent fuel amounts, facility capacity and Pu balance, which revealed the feasibility and flexibility of FFCI for LWR spent fuel reduction, high facility capacity factors and sufficient (no excess) Pu supply to FR.

The Municipal Solid Waste of Agareb (Sfax –Tunisia), characterized by high organic fraction and moisture contents is the most worrying pollution source that must be managed by innovative treatment and recycling technologies. Bio-drying, as a waste to energy conversion technology, aims at reducing moisture content of this organic matter. This concept, similar to composting, is accomplished by using the heat generated from the microbial degradation of the waste matrix, while forced aeration is used. The purpose of this work was to reduce the moisture content of the waste, by maximizing drying and minimizing organic matter biodegradation, in order to produce a solid recovered fuel with high calorific value.Keywords: Municipal solid wastes; organic matter; biodrying; composting; energy recovery.

Sustainable cities require the generation of electrical energy from those fractions of wastes that cannot be economically reused or recycled, including the “carbon dioxide neutral” biomass components. The energy content of these solid materials can be recovered by burning directly or after processing into refuse-derived fuel (RDF). Alternatively, the combustion process can be staged by the production of intermediate fuels using either pyrolysis or gasification. Co-processing of the material with coal generally increases plant utilisation and thus reduces costs.

Abstract The fuel cell program at the United States Department of Energy (DOE) National Energy Technology Laboratory (NETL) is focused on the development of low-cost, highly efficient, and reliable fossil-fuel-based solid oxide fuel cell (SOFC) power systems that can generate environmentally-friendly electric power with at least 90 percent carbon capture. NETL’s SOFC technology development roadmap is aligned with near-term market opportunities in the distributed generation sector to validate and advance the technology while paving the way for utility-scale natural gas (NG)- and coal-derived synthesis gas-fueled applications via progressively larger system demonstrations. The present study represents a part of a series of system evaluations being carried out at NETL to aid in prioritizing technological advances along research pathways to the realization of utility-scale SOFC systems, a transformational goal of the fuel cell program. In particular, the system performance of utility-scale NG fuel cell (NGFC) systems with and without carbon dioxide (CO2) capture is presented. The NGFC system analyzed features an external auto-thermal reformer (ATR) feeding the fuel to the SOFC system consisting of planar anode-supported SOFC with separated anode and cathode off-gas streams. In systems with CO2 capture, an air separation unit (ASU) is used to provide the oxygen for the ATR and for the combustion of unutilized fuel in the SOFC anode exhaust along with a CO2 purification unit to provide a nearly pure CO2 stream suitable for transport for usage in enhanced oil recovery operations or for storage in underground saline formations. Remaining thermal energy in the exhaust gases is recovered in a bottoming steam Rankine cycle while supplying any process heat requirements. A reduced order model (ROM) developed at the Pacific Northwest National Laboratory (PNNL) is used to predict the SOFC performance. The ROM, while being computationally effective for system studies, provides other detailed information about the state of the stack, such as the internal temperature gradient, generally not available from simple performance models often used to represent the SOFC. Such additional information can be important in system optimization studies to preclude operation under off-design conditions that can adversely impact overall system reliability. The NGFC system performance was analyzed by varying salient system parameters, including the percent of internal (to the SOFC module) NG reformation — ranging from 0 to 100 percent — fuel utilization, and current density. The impact of advances in underlying SOFC technology on electrical performance was also explored.

The aim of this case study is to identify the value added of existent biomass fibers (i.e., agro-industrial byproducts) and potential blends. The purpose is to explain the facts about sustainable and/or organic oil palm biomass in the energy recovery sector and in the biobased materials industry. Demand for sustainable biobased materials and energy recovery from biomass triggered the rapid growth experienced by the agricultural industry over recent years, leading to concerns about its impact on the environment and ecosystem. The agricultural industry is currently making efforts to improve sustainability practices, certifications, and to reduce carbon emissions based on innovative technologies. The used biomass, i.e. palm kernel shells (PKS), empty fruit bunches (EFB), and mesocarp fibers (MF), possesses widely accepted sustainability certifications for oil palm biomass, such as the Control Union certifications as a Roundtable on Sustainable Palm Oil (RSPO) approved certification body, the Regenerative Organic certification (ROC) for farms and products that meet the highest standards for soil health and biomass, and the EU Organic Certification in compliance with the standards and regulations of EC No. 834/2007 and EC No. 889/2008 on organic production of agricultural products. This work presents the main physicochemical characteristics of this studied biomass relevant to its energy recovery and a biobased material application. The characteristics of oil palm biomass can be summarized as a feedstock of medium energy content compared to fossil fuels and lower levels of sulfur, chlorine, and nitrogen than coal. Pellets of oil palm biomass are proven to meet expectations in both quality class A and B of non-woody pellets, i.e., characterized using the standards of solid biofuels, part 6, non-woody pellets, ISO 17225:2021. The application of biobased material ranges from pulp and paper to biobased polymer materials.

The Bingham Canyon Mine, located near Salt Lake City, Utah, is surrounded by more than 6 billion tons of waste rock developed over the open cut mining history from 1903 to present; the surface area of the waste rock is approximately 5000 acres. Waste rock dumps have a thickness of more than 1 200 feet from crest to toe. From 1930 to 2000, selected portions of the waste rock dumps were commercially leached using a ferric-sulfate-based lixiviant to extract copper, whereas other portions have only received meteoric leaching. From 2011 to present, Rio Tinto Kennecott has studied the evolution and geochemical controls on water chemistry associated with the waste rock dumps at the Bingham Canyon Mine. In this program, the waste rock dumps have been characterized in detail from the field logging of, and data collected from instrumentation installed within, 13 paired borings. At 12 of the 13 locations, the borings penetrated the full depth of the dumps, through the pre-mine soil contact, and into bedrock. Borings were installed to depths approaching 900 feet below ground surface using roto-sonic drilling methods to enable (1) core recovery and (2) measurement of near in situ properties. Field logging of the borings included Unified Soil Classification System descriptions, clast lithology, relative oxidation, paste pH, and geophysical methods (gyroscopic, temperature, neutron, and gamma). Core from the borings was analyzed for geotechnical properties (density, grain size distribution, moisture content, plasticity index and limit, and direct and block shear), quantitative evaluation of minerals by scanning electron microscopy (QEMSCAN), modified acid-base accounting (ABA), modified synthetic precipitation leaching procedure (SPLP), and hyperspectral analysis by CoreScan. If water was encountered during the drilling process at sufficient volumes for collection from the core barrel, samples were collected for chemical analysis. Instrumentation installed within the borings included lysimeters, thermistor nodes, direct temperature sensing (DTS) fiber optic cables, time domain reflectometry (TDR), shear cables, gas (oxygen, carbon dioxide) measurement tubes, and vibrating wire piezometers (VWPs). Additionally, each drill site had multiple measurements of oxygen consumption in the surface layer of the local waste rock. Data acquired from the borings were linked with historical information (covering a period of greater than 50 years) from extensive drilling, mineralogical and litho-geochemical evaluations, hydraulic and tracer testing, and 20 years of seepage f low and water chemistry data to develop a conceptual model that describes the hydraulic, geochemical, and physical behavior of the waste rock dumps. Pyrite and other sulfide minerals in the waste rock dumps are oxidized by both diffusive and convective ingress of air, producing acidic, high-total dissolved solids effluents, and jarosite that has formed within the waste rock as a secondary phase that stores additional acidity. The dominant air ingress mechanism is convection, which accounts for greater than 90% of the sulfide oxidation within the waste rock dumps. Based on temperature profiles and water balance for the dumps, moisture loss to geochemical reactions is a significant part of the water budget.

Banco de la República is celebrating its 100th anniversary in 2023. This is a very significant anniversary and one that provides an opportunity to highlight the contribution the Bank has made to the country’s development. Its track record as guarantor of monetary stability has established it as the one independent state institution that generates the greatest confidence among Colombians due to its transparency, management capabilities, and effective compliance with the central banking and cultural responsibilities entrusted to it by the Constitution and the Law. On a date as important as this, the Board of Directors of Banco de la República (BDBR) pays tribute to the generations of governors and officers whose commitment and dedication have contributed to the growth of this institution.1 Banco de la República’s mandate was confirmed in the National Constitutional Assembly of 1991 where the citizens had the opportunity to elect the seventy people who would have the task of drafting a new constitution. The leaders of the three political movements with the most votes were elected as chairs to the Assembly, and this tripartite presidency reflected the plurality and the need for consensus among the different political groups to move the reform forward. Among the issues considered, the National Constitutional Assembly gave special importance to monetary stability. That is why they decided to include central banking and to provide Banco de la República with the necessary autonomy to use the instruments for which they are responsible without interference from other authorities. The constituent members understood that ensuring price stability is a state duty and that the entity responsible for this task must be enshrined in the Constitution and have the technical capability and institutional autonomy necessary to adopt the decisions they deem appropriate to achieve this fundamental objective in coordination with the general economic policy. In particular, Article 373 established that “the State, through Banco de la República, shall ensure the maintenance of the purchasing power of the currency,” a provision that coincided with the central banking system adopted by countries that have been successful in controlling inflation. In 1999, in Ruling 481, the Constitutional Court stated that “the duty to maintain the purchasing power of the currency applies to not only the monetary, credit, and exchange authority, i.e., the Board of Banco de la República, but also those who have responsibilities in the formulation and implementation of the general economic policy of the country” and that “the basic constitutional purpose of Banco de la República is the protection of a sound currency. However, this authority must take the other economic objectives of state intervention such as full employment into consideration in their decisions since these functions must be coordinated with the general economic policy.” The reforms to Banco de la República agreed upon in the Constitutional Assembly of 1991 and in Act 31/1992 can be summarized in the following aspects: i) the Bank was assigned a specific mandate: to maintain the purchasing power of the currency in coordination with the general economic policy; ii) the BDBR was designatedas the monetary, foreign exchange, and credit authority; iii) the Bank and its Board of Directors were granted a significant degree of independence from the government; iv) the Bank was prohibited from granting credit to the private sector except in the case of the financial sector; v) established that in order to grant credit to the government, the unanimous vote of its Board of Directors was required except in the case of open market transactions; vi) determined that the legislature may, in no case, order credit quotas in favor of the State or individuals; vii) Congress was appointed, on behalf of society, as the main addressee of the Bank’s reporting exercise; and viii) the responsibility for inspection, surveillance, and control over Banco de la República was delegated to the President of the Republic. The members of the National Constitutional Assembly clearly understood that the benefits of low and stable inflation extend to the whole of society and contribute mto the smooth functioning of the economic system. Among the most important of these is that low inflation promotes the efficient use of productive resources by allowing relative prices to better guide the allocation of resources since this promotes economic growth and increases the welfare of the population. Likewise, low inflation reduces uncertainty about the expected return on investment and future asset prices. This increases the confidence of economic agents, facilitates long-term financing, and stimulates investment. Since the low-income population is unable to protect itself from inflation by diversifying its assets, and a high proportion of its income is concentrated in the purchase of food and other basic goods that are generally the most affected by inflationary shocks, low inflation avoids arbitrary redistribution of income and wealth.2 Moreover, low inflation facilitates wage negotiations, creates a good labor climate, and reduces the volatility of employment levels. Finally, low inflation helps to make the tax system more transparent and equitable by avoiding the distortions that inflation introduces into the value of assets and income that make up the tax base. From the monetary authority’s point of view, one of the most relevant benefits of low inflation is the credibility that economic agents acquire in inflation targeting, which turns it into an effective nominal anchor on price levels. Upon receiving its mandate, and using its autonomy, Banco de la República began to announce specific annual inflation targets as of 1992. Although the proposed inflation targets were not met precisely during this first stage, a downward trend in inflation was achieved that took it from 32.4% in 1990 to 16.7% in 1998. At that time, the exchange rate was kept within a band. This limited the effectiveness of monetary policy, which simultaneously sought to meet an inflation target and an exchange rate target. The Asian crisis spread to emerging economies and significantly affected the Colombian economy. The exchange rate came under strong pressure to depreciate as access to foreign financing was cut off under conditions of a high foreign imbalance. This, together with the lack of exchange rate flexibility, prevented a countercyclical monetary policy and led to a 4.2% contraction in GDP that year. In this context of economic slowdown, annual inflation fell to 9.2% at the end of 1999, thus falling below the 15% target set for that year. This episode fully revealed how costly it could be, in terms of economic activity, to have inflation and exchange rate targets simultaneously. Towards the end of 1999, Banco de la República announced the adoption of a new monetary policy regime called the Inflation Targeting Plan. This regime, known internationally as ‘Inflation Targeting,’ has been gaining increasing acceptance in developed countries, having been adopted in 1991 by New Zealand, Canada, and England, among others, and has achieved significant advances in the management of inflation without incurring costs in terms of economic activity. In Latin America, Brazil and Chile also adopted it in 1999. In the case of Colombia, the last remaining requirement to be fulfilled in order to adopt said policy was exchange rate flexibility. This was realized around September 1999, when the BDBR decided to abandon the exchange-rate bands to allow the exchange rate to be freely determined in the market.Consistent with the constitutional mandate, the fundamental objective of this new policy approach was “the achievement of an inflation target that contributes to maintaining output growth around its potential.”3 This potential capacity was understood as the GDP growth that the economy can obtain if it fully utilizes its productive resources. To meet this objective, monetary policy must of necessity play a countercyclical role in the economy. This is because when economic activity is below its potential and there are idle resources, the monetary authority can reduce the interest rate in the absence of inflationary pressure to stimulate the economy and, when output exceeds its potential capacity, raise it. This policy principle, which is immersed in the models for guiding the monetary policy stance, makes the following two objectives fully compatible in the medium term: meeting the inflation target and achieving a level of economic activity that is consistent with its productive capacity. To achieve this purpose, the inflation targeting system uses the money market interest rate (at which the central bank supplies primary liquidity to commercial banks) as the primary policy instrument. This replaced the quantity of money as an intermediate monetary policy target that Banco de la República, like several other central banks, had used for a long time. In the case of Colombia, the objective of the new monetary policy approach implied, in practical terms, that the recovery of the economy after the 1999 contraction should be achieved while complying with the decreasing inflation targets established by the BDBR. The accomplishment of this purpose was remarkable. In the first half of the first decade of the 2000s, economic activity recovered significantly and reached a growth rate of 6.8% in 2006. Meanwhile, inflation gradually declined in line with inflation targets. That was how the inflation rate went from 9.2% in 1999 to 4.5% in 2006, thus meeting the inflation target established for that year while GDP reached its potential level. After this balance was achieved in 2006, inflation rebounded to 5.7% in 2007, above the 4.0% target for that year due to the fact that the 7.5% GDP growth exceeded the potential capacity of the economy.4 After proving the effectiveness of the inflation targeting system in its first years of operation, this policy regime continued to consolidate as the BDBR and the technical staff gained experience in its management and state-of-the-art economic models were incorporated to diagnose the present and future state of the economy and to assess the persistence of inflation deviations and expectations with respect to the inflation target. Beginning in 2010, the BDBR established the long-term 3.0% annual inflation target, which remains in effect today. Lower inflation has contributed to making the macroeconomic environment more stable, and this has favored sustained economic growth, financial stability, capital market development, and the functioning of payment systems. As a result, reductions in the inflationary risk premia and lower TES and credit interest rates were achieved. At the same time, the duration of public domestic debt increased significantly going from 2.27 years in December 2002 to 5.86 years in December 2022, and financial deepening, measured as the level of the portfolio as a percentage of GDP, went from around 20% in the mid-1990s to values above 45% in recent years in a healthy context for credit institutions.Having been granted autonomy by the Constitution to fulfill the mandate of preserving the purchasing power of the currency, the tangible achievements made by Banco de la República in managing inflation together with the significant benefits derived from the process of bringing inflation to its long-term target, make the BDBR’s current challenge to return inflation to the 3.0% target even more demanding and pressing. As is well known, starting in 2021, and especially in 2022, inflation in Colombia once again became a serious economic problem with high welfare costs. The inflationary phenomenon has not been exclusive to Colombia and many other developed and emerging countries have seen their inflation rates move away from the targets proposed by their central banks.5 The reasons for this phenomenon have been analyzed in recent Reports to Congress, and this new edition delves deeper into the subject with updated information. The solid institutional and technical base that supports the inflation targeting approach under which the monetary policy strategy operates gives the BDBR the necessary elements to face this difficult challenge with confidence. In this regard, the BDBR reiterated its commitment to the 3.0% inflation target in its November 25 communiqué and expects it to be reached by the end of 2024.6 Monetary policy will continue to focus on meeting this objective while ensuring the sustainability of economic activity, as mandated by the Constitution. Analyst surveys done in March showed a significant increase (from 32.3% in January to 48.5% in March) in the percentage of responses placing inflation expectations two years or more ahead in a range between 3.0% and 4.0%. This is a clear indication of the recovery of credibility in the medium-term inflation target and is consistent with the BDBR’s announcement made in November 2022. The moderation of the upward trend in inflation seen in January, and especially in February, will help to reinforce this revision of inflation expectations and will help to meet the proposed targets. After reaching 5.6% at the end of 2021, inflation maintained an upward trend throughout 2022 due to inflationary pressures from both external sources, associated with the aftermath of the pandemic and the consequences of the war in Ukraine, and domestic sources, resulting from: strengthening of local demand; price indexation processes stimulated by the increase in inflation expectations; the impact on food production caused by the mid-2021 strike; and the pass-through of depreciation to prices. The 10% increase in the minimum wage in 2021 and the 16% increase in 2022, both of which exceeded the actual inflation and the increase in productivity, accentuated the indexation processes by establishing a high nominal adjustment benchmark. Thus, total inflation went to 13.1% by the end of 2022. The annual change in food prices, which went from 17.2% to 27.8% between those two years, was the most influential factor in the surge in the Consumer Price Index (CPI). Another segment that contributed significantly to price increases was regulated products, which saw the annual change go from 7.1% in December 2021 to 11.8% by the end of 2022. The measure of core inflation excluding food and regulated items, in turn, went from 2.5% to 9.5% between the end of 2021 and the end of 2022. The substantial increase in core inflation shows that inflationary pressure has spread to most of the items in the household basket, which is characteristic of inflationary processes with generalized price indexation as is the case in Colombia. Monetary policy began to react early to this inflationary pressure. Thus, starting with its September 2021 session, the BDBR began a progressive change in the monetary policy stance moving away from the historical low of a 1.75% policy rate that had intended to stimulate the recovery of the economy. This adjustment process continued without interruption throughout 2022 and into the beginning of 2023 when the monetary policy rate reached 12.75% last January, thus accumulating an increase of 11 percentage points (pp). The public and the markets have been surprised that inflation continued to rise despite significant interest rate increases. However, as the BDBR has explained in its various communiqués, monetary policy works with a lag. Just as in 2022 economic activity recovered to a level above the pre-pandemic level, driven, along with other factors, by the monetary stimulus granted during the pandemic period and subsequent months, so too the effects of the current restrictive monetary policy will gradually take effect. This will allow us to expect the inflation rate to converge to 3.0% by the end of 2024 as is the BDBR’s purpose.Inflation results for January and February of this year showed declining marginal increases (13 bp and 3 bp respectively) compared to the change seen in December (59 bp). This suggests that a turning point in the inflation trend is approaching. In other Latin American countries such as Chile, Brazil, Perú, and Mexico, inflation has peaked and has begun to decline slowly, albeit with some ups and downs. It is to be expected that a similar process will take place in Colombia in the coming months. The expected decline in inflation in 2023 will be due, along with other factors, to lower cost pressure from abroad as a result of the gradual normalization of supply chains, the overcoming of supply shocks caused by the weather, and road blockades in previous years. This will be reflected in lower adjustments in food prices, as has already been seen in the first two months of the year and, of course, the lagged effect of monetary policy. The process of inflation convergence to the target will be gradual and will extend beyond 2023. This process will be facilitated if devaluation pressure is reversed. To this end, it is essential to continue consolidating fiscal sustainability and avoid messages on different public policy fronts that generate uncertainty and distrust. 1 This Report to Congress includes Box 1, which summarizes the trajectory of Banco de la República over the past 100 years. In addition, under the Bank’s auspices, several books that delve into various aspects of the history of this institution have been published in recent years. See, for example: Historia del Banco de la República 1923-2015; Tres banqueros centrales; Junta Directiva del Banco de la República: grandes episodios en 30 años de historia; Banco de la República: 90 años de la banca central en Colombia. 2 This is why lower inflation has been reflected in a reduction of income inequality as measured by the Gini coefficient that went from 58.7 in 1998 to 51.3 in the year prior to the pandemic. 3 See Gómez Javier, Uribe José Darío, Vargas Hernando (2002). “The Implementation of Inflation Targeting in Colombia”. Borradores de Economía, No. 202, March, available at: https://repositorio.banrep.gov.co/handle/20.500.12134/5220 4 See López-Enciso Enrique A.; Vargas-Herrera Hernando and Rodríguez-Niño Norberto (2016). “The inflation targeting strategy in Colombia. An historical view.” Borradores de Economía, No. 952. https://repositorio.banrep.gov.co/handle/20.500.12134/6263 5 According to the IMF, the percentage change in consumer prices between 2021 and 2022 went from 3.1% to 7.3% for advanced economies, and from 5.9% to 9.9% for emerging market and developing economies. 6 https://www.banrep.gov.co/es/noticias/junta-directiva-banco-republica-reitera-meta-inflacion-3