Performance of a fluidized bed-fired Stirling engine as micro-scale combined heat and power system on wood pellets

Schneider, T.; Ruf, Florian; Müller, Dominik; Karl, Jürgen

doi:10.1016/j.applthermaleng.2021.116712

Cited by 18 publications

(7 citation statements)

References 40 publications

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“…During these experiments this is only noticeable by a reduced electrical heating duty (approximately 3%). However, with regard to subsequent applications for OCAC, like the heating of an in-bed heat exchanger, the maximum heat release in the fluidized bed is decisive. , …”

Section: Resultsmentioning

confidence: 99%

“…However, with regard to subsequent applications for OCAC, like the heating of an in-bed heat exchanger, the maximum heat release in the fluidized bed is decisive. 8,47 Influence of the fluidization velocity. In order to verify the impact of ilmenite on the combustion process and to mitigate possible imperfect mixing effects, the fluidization velocity was increased at constant combustion parameters (λ = 1.5, ϑ FB = 800°C).…”

Section: ■ Results and Discussionmentioning

confidence: 99%

“…Concerning these differences, this research concentrates on the application of an oxygen carrier, natural ilmenite, in small-scale bubbling fluidized bed combustion systems. Especially, the effects of larger particles, dense fluidized beds, and the absence of secondary measures to keep systems simple and affordable are in the focus . The objective of the presented investigations in a laboratory BFB was to define the general influence of the excess air ratio as well as of the fluidization velocity and bed height on the surplus oxygen supply and oxygen distribution in the bed.…”

Section: Introductionmentioning

confidence: 99%

“…Especially, the effects of larger particles, dense fluidized beds, and the absence of secondary measures to keep systems simple and affordable are in the focus. 8 The objective of the presented investigations in a laboratory BFB was to define the general influence of the excess air ratio as well as of the fluidization velocity and bed height on the surplus oxygen supply and oxygen distribution in the bed. Methane served as the gaseous model fuel.…”

Section: ■ Introductionmentioning

confidence: 99%

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Investigation of the Oxygen Supply and Distribution in a Bubbling Fluidized Bed by Using Natural Ilmenite for Oxygen Carrier Aided Combustion

et al. 2021

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The application of oxygen carrier materials has one of its origins in the chemical looping combustion processes, which aim at inherent CO2 sequestration by realizing fuel oxidation in the absence of combustion air. This concept can be transferred to conventional fluidized bed combustion processes, the so-called oxygen carrier aided combustion. The replacement of the conventionally applied bed material with an oxygen carrier focuses mainly on large-scale circulating fluidized bed combustion plants. The main stated performance improvements include the reduction of carbon monoxide emissions even at lower excess air ratios and the enhancement of the combustion efficiency. Nevertheless, the ability of shifting oxygen in space and time is of certain interest especially in small-scale bubbling fluidized bed systems. Imperfect fuel mixing, limited residence time in the dense bed zone, as well as limited system complexity often mitigate their combustion performance. Process conditions in bubbling fluidized beds differ from those prevalent in circulating beds regarding bed material particle size distribution, fluidization velocities, or particle volume fraction in the bed. Within this study, the widely used oxygen carrier ilmenite serves as bed material in a laboratory bubbling fluidized bed combustion. The focus was on the oxygen distribution profiles and their shift by ilmenite into the bed during methane combustion. The variation of the excess air ratio, fluidization velocity, and bed height reveal a significant increase of the in-bed CO2 yield (max. 55%) within ilmenite experiments. Moreover, the oxygen conversion profile confirms the shift of the oxygen supply by ilmenite from the lower reactor part to the reduction dominated zone. The amount of shifted oxygen increases at lower excess air ratios. Thus, full conversion is not achieved as kinetics and limited residence time in the bed inhibit the fuel conversion.

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Section: Resultsmentioning

confidence: 99%

Section: ■ Results and Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: ■ Introductionmentioning

confidence: 99%

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Investigation of the Oxygen Supply and Distribution in a Bubbling Fluidized Bed by Using Natural Ilmenite for Oxygen Carrier Aided Combustion

et al. 2021

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“…In Doty and Turner (2009), the term "distributed generation" (for complete independence from a centralized grid) refers to the generation of combined heat and power (CHP) ranging from several kW's to 25 MW e . Decentralization of energy production is part of the new energy generation measures, and CHP, for instance, for domestic applications and low dense areas, is an efficient option being explored for at least 20 years (Smith and Few, 2001;Schneider et al, 2021). In particular, Cockroft and Kelly (2006) and Thiers et al (2010) identified small fuel cell (FC) stationary installations (called "micro-CHP") that can produce power up to 50 kW e , while large stationary FC systems can be well over 100 kW e in size.…”

Section: Introductionmentioning

confidence: 99%

Techno-Economic Optimization of an Integrated Biomass Waste Gasifier–Solid Oxide Fuel Cell Plant

Pérez–Fortes

Nakajo

et al. 2021

Front. Energy Res.

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With a growing energy demand in a carbon-constrained society, fuels cells powered by renewable fuels, and specifically solid waste, are seen as interesting contributors to the energy portfolio. The alternative energy industry needs to reduce costs, enhance efficiency, and demonstrate durability and reliability to be economically feasible and attractive. This paper addresses biomass waste gasification in distributed energy systems, using a solid oxide fuel cell (SOFC) to produce electricity and heat. The potential and optimal plant efficiency and layout (i.e., anode off-gas (AOG) recirculation point via small-scale turbomachinery and heat exchanger network) are analyzed through a multi-stage approach that includes scenario evaluation and multi-objective optimization via a hybrid optimization strategy with heuristics and mathematical programming. The results in this paper summarize the most convenient operating conditions and provide an optimized heat exchanger network (HEN). The AOG recirculation toward the gasifier combustor is the preferred option; the electrical and thermal efficiencies can separately go up to 49 and 47%, respectively. The combined total efficiency ranges between 76 and 82%, and the area of heat exchange, which corresponds to an amount of heat exchanged between 91 and 117 kW, is within 6–14 m2.

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Biomass for Power Production and Cogeneration

Malico

2024

Green Energy and Technology

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Performance of a fluidized bed-fired Stirling engine as micro-scale combined heat and power system on wood pellets

Cited by 18 publications

References 40 publications

Investigation of the Oxygen Supply and Distribution in a Bubbling Fluidized Bed by Using Natural Ilmenite for Oxygen Carrier Aided Combustion

Investigation of the Oxygen Supply and Distribution in a Bubbling Fluidized Bed by Using Natural Ilmenite for Oxygen Carrier Aided Combustion

Techno-Economic Optimization of an Integrated Biomass Waste Gasifier–Solid Oxide Fuel Cell Plant

Biomass for Power Production and Cogeneration

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