Emissions and combustion performance of a micro gas turbine powered with liquefied wood and its blends

The combustion of a viscous biofuel, liquefied wood (LW) produced via solvolysis of lignocellulosic biomass in acidified glycols, has been studied in a small gas turbine rig. The test rig includes a modified injection line which is compatible with acidic, viscous biofuels allowing fuel preheating and two pilot injectors, and a re-designed combustion chamber. The link between fuel properties and combustion performance of liquefied wood is investigated by burning the biofuel at different blending ratios with ethanol. Exhaust emissions have been compared to reference measurements with diesel fuel and ethanol. Combustion analysis is supported by the investigation of the engine operating parameters and the main emission species at different electrical loads. The experimental study reveals that it is possible to establish efficient operation of the micro gas turbine while utilizing liquefied wood-ethanol blends with high share of liquefied wood

Inovativna tehnologija uplinjanja za krožno gospodarstvo

This article presents a novel gasification technology process in the context of achieving carbon neutrality by establishing a sustainable circulation of carbonaceous materials with a focus on the production of virgin materials from various kinds of waste. The technology can alleviate the key limitations of existing gasification systems, which are the production and management of residue tars. The innovative technology process re-utilizes tars within the reaction itself, enabling an endless cycle of carbon. It also ensures high flexibility for efficiently handling heterogenic waste materials.Članek predstavlja nov tehnološki postopek uplinjanja v okviru doseganja ogljikove nevtralnosti z vzpostavitvijo trajnostnega kroženja ogljikovih materialov s fokusom na proizvodnji izvornih surovin iz različnih vrst odpadkov. Tehnologija lahko reši ključne omejitve obstoječih sistemov uplinjanja, to je proizvodnja in upravljanje ostankov katrana. Inovativni tehnološki postopek uporabi katrane v sami reakciji, kar omogoča neskončno kroženje ogljika. Zagotavlja tudi visoko prilagodljivost za učinkovito ravnanje s heterogenimi odpadnimi materiali

Surrogate model for improved simulations of small-scale sludge incineration plants

Although various modelling approaches exist for the simulation of solid fuel combustion, no specific model hasbeen developed for the accurate description of gas-phase combustion in small-scale combustion devices. This isparticularly limiting in scenarios when volatile-rich, complex and incompletely described solid fuels such assewage sludge are used. To address this issue, an accurate description of combustion from the fuel bed onwardsis required as well as an improved description of emitted volatiles. This paper introduces an innovative surro-gate-based combustion model that combines data on sludge devolatilisation and measured combustion char-acteristics to offer a new surrogate composition. The composition includes heavy hydrocarbon species to ac-curately describe combustion evolution. A sensitivity analysis revealed that H2contributes significantly tocombustion evolution, while the most robust surrogate composition is obtained when ethanol is used as a leadingrepresentative of heavier hydrocarbons. The model can be used to produce suitable surrogates for the mainsludge combustion interval, offering the required improvement in fuel descriptions and accuracy of simulationsin the vicinity of the fuel bed. Hence, this model is particularly suitable for the optimisation of temperature, heatrelease rate, and concentration field in combustion chambers with limited volumes

Combustion and emission formation phenomena of tire pyrolysis oil in a common rail Diesel engine

A pure tire pyrolysis oil produced from waste tires was utilized in a modern 4-cylinder, turbocharged and intercooled, automotive Diesel engine. Due to its low cetane number, cetane improvers, external energy addition or increased compression ratios are generally required for its use in Diesel engines. Successful utilization of pure tire pyrolysis oil is also achievable with the addition of pilot injection but limited to mid- to high-load operating range. The first objective of the present study is therefore focused on further extension of the operating range towards lower loads by novel combined application of the exhaust gas recirculation and tailored main injection strategy. As the second objective, the article provides for the first time an in-depth analysis of the particulate emissions of the tire pyrolysis oil measured with two different methods. In this area it identifies and reasons challenges related to determination of the particulate emissions for alternative fuels. The original contribution of the presented approach thus arises from the holistic assessment of interactions between the exhaust gas recirculation ratios, injection parameters and combustion as well as gaseous and particulate emissions formation phenomena

Integration of energy systems, circular economy and efficiency measures

With realization that world\u27s resources are limited, a number of initiatives in all global regions emerged to pursue a common goal of sustainable management of energy and material loops. The intensively researched topics are traditionally gathered under the roof of Sustainable Development of Energy, Water and Environmental Systems conferences (SDEWES), which in its 16th edition saw a highly focused and impacting research contributions, tackling the cross-sectoral development and introduction of novel technologies and processes, all devoted to implementation and examination of possible solutions to contribute to Sustainable Development Goals (SDGs). The present paper is gathering and structuring these contributions, enriched with the outcomes of previous SDEWES conferences to enlighten the advances made in the fields of energy harvesting, circular economy and efficient energy use to put into context the role of cleaner chemical engineering. By this, it provides a basis and a guidance for future research on the axis of material-resource-energy nexus which is in the paper identified as an extensively interlinked research area, difficult to be tackled individually and still requiring an important effort to collectively address the cross-sectoral dimension of the challenge

Real-world fuel consumption, fuel cost and exhaust emissions of different bus powertrain technologies

Air quality in urban areas is strongly influenced by exhaust emitted by the public transport fleet. The aim of this study was to analyze benefits in the fuel consumption, fuel costs and exhaust emissions when replacing baseline diesel fueled EURO III city buses by the compressed natural gas (CNG)-fueled EURO V buses and by hydraulic series hybrid diesel-fueled EURO V buses. Real-world measurements were performed on the regular bus route to access realistic energy consumption and exhaust emissions. Instantaneous gaseous emission (CO$_2$, CO, NO$_x$ and THC) were measured together with the instantaneous PM$_{10}$ mass emission. Innovativeness of the presented approach thus arises from the systematic comparison of different powertrain technologies under real-world drive cycles and measuring time traces of not only gaseous but also of PM$_{10}$ mass emissions. Furthermore, lumped cycle averaged emissions are interpreted and explained by typical powertrain performance parameters and exhaust emission time traces. Cumulative results indicate that application of the CNG fueled buses does not necessary reduce CO$_2$ emissions compared to diesel-fueled buses whereas reduction in fuel costs is evident. Additionally, it is shown that hybrid operation of the hydraulic series hybrid diesel-fueled bus resulted in higher fuel consumption due to poorly optimized hybrid topology and control strategy. Furthermore, analyses of the time traces point out inadequate lambda control of CNG-fueled buses and nucleation mode-based particle number emissions during deceleration

Emissions and combustion performance of a micro gas turbine powered with liquefied wood and its blends

The combustion of a viscous biofuel, liquefied wood (LW) produced via solvolysis of lignocellulosic biomass in acidified glycols, has been studied in a small gas turbine rig. The test rig includes a modified injection line which is compatible with acidic, viscous biofuels allowing fuel preheating and two pilot injectors, and a re-designed combustion chamber. The link between fuel properties and combustion performance of liquefied wood is investigated by burning the biofuel at different blending ratios with ethanol. Exhaust emissions have been compared to reference measurements with diesel fuel and ethanol. Combustion analysis is supported by the investigation of the engine operating parameters and the main emission species at different electrical loads. The experimental study reveals that it is possible to establish efficient operation of the micro gas turbine while utilizing liquefied wood-ethanol blends with high share of liquefied wood

Bioliquids and their use in power generation

The first EU Renewable Energy Directive (RED) served as an effective push for world-wide research efforts on biofuels and bioliquids, i.e. liquid fuels for energy purposes other than for transport, including electricity, heating, and cooling, which are produced from biomass. In December 2018 the new RED II was published in the Official Journal of the European Union. Therefore, it is now the right time to provide a comprehensive overview of achievements and practices that were developed within the current perspective. To comply with this objective, the present study focuses on a comprehensive and systematic technical evaluation of all key aspects of the different distributed energy generation pathways using bioliquids in reciprocating engines and micro gas turbines that were overseen by these EU actions. Methodologically, the study originates from the analyses of feedstock and fuel processing technologies, which decisively influence fuel properties. The study systematically and holistically highlights the utilisation of these bioliquids in terms of fuel property specific challenges, required engine adaptations, and equipment durability, culminating in analyses of engine performance and emissions. In addition, innovative proposals and future opportunities for further technical improvements in the whole production-consumption cycle are presented, thus serving as a guideline for upcoming research and development activities in the fast-growing area of bioliquids. Additionally, the paper systematically addresses opportunities for the utilisation of waste streams, emerging from the ever increasing circular use of materials and resources. With this, the present review provides the sorely needed link between past efforts, oriented towards the exploitation of bio-based resources for power generation, and the very recent zero-waste oriented society that will require a realistic exploitation plan for residuals originating from intensive material looping

Operational stability of a spark ignition engine fuelled by low H2 content synthesis gas

The paper focuses on the implementation of a comprehensive and robust optimization procedure for a synthesis gas fired four-cylinder, spark ignited, 2.2 L industrial engine used in combined heat and power applications. Innovatively designed workflow is for the first time incorporating also a thorough operational stability analysis for evaluation of the engine operation durability while using off-design fuels. Design constraints of the engine operational space are set after in depth investigation of knock phenomena, cycle to cycle variations, emission formation phenomena and engine performance parameters. These are derived from experimental data, obtained from the engine, equipped with newly designed components. Throughout the paper, results obtained with synthesis gas are benchmarked to natural gas. With significant emphasis laid on analysis of lean operation conditions, as a measure to reduce environmental footprint of energy generation, a newly proposed optimum operation points reveal a possibility to obtain TA-Luft and EPA emission limits already with stoichiometric mixture. This allows to achieve a remarkably low power de-rating factor of only 16.5% and omission of any aftertreatment system. Therefore, findings of this study represent a significant improvement of current control strategies and enable further increase in specific power and thus economic attractiveness of distributed power generation techniques at enhanced durability while using low-carbon and renewable fuels

Performance and emissions of liquefied wood as fuel for a small scale gas turbine

This study investigates for the first time the combustion in a micro gas turbine (MGT) of a new bioliquid, a viscous biocrude, which is a liquefied wood (LW) produced via solvolysis of lignocellulosic biomass in acidified glycols. The test rig includes a modified fuel injection line, a re-designed combustion chamber and revised fuel injection positions. The main novelties of this work are: (1) producing of liquefied wood with pure ethylene glycol as a solvent, and methanesulfonic acid as a catalyst, to obtain a bio-crude with lower viscosity and higher lignocellulosics content than previous tested formulations(2) upgrading raw liquefied wood by blending it with ethanol to further reduce the viscosity of the mixture(3) utilizing a commercially available MGT Auxiliary Power Unit (APU) of 25%kW electrical power output, with notably reduced extent of adaptations to use the newly obtained fuel mixture. Fuel properties, and their impact on combustion performance using liquefied wood, are investigated by analyzing MGT performance and emissions response at different load and blend ratios. Emissions revealed that the presence of LW in the blends significantly affects CO and NOX concentrations compared to conventional fuels. CO roughly increased from 600%ppm (pure ethanol as fuel) to 1500%ppm (at 20%kW electrical power). The experimental study reveals that it is possible to achieve efficient MGT operation while utilizing high biocrude to ethanol ratios, but a number of adaptations are necessary. The achieved maximum share of liquefied wood in the fuel blend is 47.2% at 25%kW power output. Main barriers to the use of higher share of liquefied wood in these type of systems are also summarized