Editorial

5 pages, 208 KiB

Open AccessEditorial

by Eliseu Monteiro and Sérgio Ferreira

Energies 2022, 15(16), 5943; https://doi.org/10.3390/en15165943 - 17 Aug 2022

Cited by 11 | Viewed by 1683

Environmental problems associated with global energy supply systems and the increasing amount of global solid waste production are triggering a shift towards a greater reliance on biomass waste. Waste-to-energy systems have become important for industries and scientists because of the increasing interest in [...] Read more.

Environmental problems associated with global energy supply systems and the increasing amount of global solid waste production are triggering a shift towards a greater reliance on biomass waste. Waste-to-energy systems have become important for industries and scientists because of the increasing interest in energy production from waste, due to improved efficiency and cost-effective solutions. The shift to biomass is also essential for industries to use their own waste to produce their own energy, which is in line with circular economy concepts. This Special Issue “Biomass Wastes for Energy Production” of Energies comprises ten (10) papers, including one review article, that represent the latest advances of waste-to-energy technologies and contribute to the rethinking of global energy supply systems. The Guest Editor also highlights other relevant topics that fall beyond the coverage of the published articles. Full article

(This article belongs to the Special Issue Biomass Wastes for Energy Production)

Research

Jump to: Editorial

15 pages, 1131 KiB

Open AccessArticle

Improving Municipal Solid Waste Management Strategies of Montréal (Canada) Using Life Cycle Assessment and Optimization of Technology Options

by Tahereh Malmir, Saeed Ranjbar and Ursula Eicker

Energies 2020, 13(21), 5701; https://doi.org/10.3390/en13215701 - 31 Oct 2020

Cited by 8 | Viewed by 3504

Abstract

Landfilling of organic waste is still the predominant waste management method in Canada. Data collection and analysis of the waste were done for the case study city of Montréal in Canada. A life cycle assessment was carried out for the current and proposed [...] Read more.

Landfilling of organic waste is still the predominant waste management method in Canada. Data collection and analysis of the waste were done for the case study city of Montréal in Canada. A life cycle assessment was carried out for the current and proposed waste management system using the IWM-2 software. Using life cycle assessment results, a non-dominated sorting genetic algorithm was used to optimize the waste flows. The optimization showed that the current recovery ratio of organic waste of 23% in 2017 could be increased to 100% recovery of food waste. Also, recycling could be doubled, and landfilling halved. The objective functions were minimizing the total energy consumption and CO_2eq emissions as well as the total cost in the waste management system. By using a three-objective optimization algorithm, the optimized waste flow for Montréal results in 2% of waste (14.7 kt) to anaerobic digestion (AD), 7% (66.3 kt) to compost, 32% (295 kt) to recycling, 1% (8.5 kt) to incineration, and 58% (543 kt) to landfill. Full article

(This article belongs to the Special Issue Biomass Wastes for Energy Production)

► Show Figures

Figure 1

31 pages, 6671 KiB

Open AccessArticle

Techno-Economic Assessment of the Use of Syngas Generated from Biomass to Feed an Internal Combustion Engine

by J. R. Copa, C. E. Tuna, J. L. Silveira, R. A. M. Boloy, P. Brito, V. Silva, J. Cardoso and D. Eusébio

Energies 2020, 13(12), 3097; https://doi.org/10.3390/en13123097 - 15 Jun 2020

Cited by 20 | Viewed by 3859

Abstract

The focus of this study is to provide a comparative techno-economic analysis concerning the deployment of small-scale gasification systems in dealing with various fuels from two countries, Portugal and Brazil, for electricity generation in a 15 kWe downdraft gasifier. To quantify this, a [...] Read more.

The focus of this study is to provide a comparative techno-economic analysis concerning the deployment of small-scale gasification systems in dealing with various fuels from two countries, Portugal and Brazil, for electricity generation in a 15 kWe downdraft gasifier. To quantify this, a mathematical model was implemented and validated against experimental runs gathered from the downdraft reactor. Further, a spreadsheet economic model was developed combining the net present value (NPV), internal rate of return (IRR) and the payback period (PBP) over the project’s lifetime set to 25 years. Cost factors included expenses related to electricity generation, initial investment, operation and maintenance and fuel costs. Revenues were estimated from the electricity sales to the grid. A Monte Carlo sensitivity analysis was used to measure the performance of the economic model and determine the investment risk. The analysis showed an electricity production between 11.6 to 15 kW, with a general system efficiency of approximately 13.5%. The viability of the projects was predicted for an NPV set between 18.99 to 31.65 k€, an IRR between 16.88 to 20.09% and a PBP between 8.67 to 12.61 years. The risk assessment yielded favorable investment projections with greater risk of investment loss in the NPV and the lowest for IRR. Despite the feasibility of the project, the economic performance proved to be highly reliant on the electricity sales prices subdue of energy market uncertainties. Also, regardless of the broad benefits delivered by these systems, their viability is still strikingly influenced by governmental decisions, subsidiary support and favorable electricity sales prices. Overall, this study highlights the empowering effect of small-scale gasification systems settled in decentralized communities for electric power generation. Full article

(This article belongs to the Special Issue Biomass Wastes for Energy Production)

► Show Figures

Figure 1

16 pages, 1622 KiB

Open AccessArticle

Can Multiple Uses of Biomass Limit the Feedstock Availability for Future Biogas Production? An Overview of Biogas Feedstocks and Their Alternative Uses

by Dieu Linh Hoang, Chris Davis, Henri C. Moll and Sanderine Nonhebel

Energies 2020, 13(11), 2747; https://doi.org/10.3390/en13112747 - 30 May 2020

Cited by 5 | Viewed by 3127

Abstract

Biogas is expected to contribute 10% of the total renewable energy use in Europe in 2030. This expectation largely depends on the use of several biomass byproducts and wastes as feedstocks. However, the current development of a biobased economy requires biomass sources for [...] Read more.

Biogas is expected to contribute 10% of the total renewable energy use in Europe in 2030. This expectation largely depends on the use of several biomass byproducts and wastes as feedstocks. However, the current development of a biobased economy requires biomass sources for multiple purposes. If alternative applications also use biogas feedstocks, it becomes doubtful whether they will be available for biogas production. To explore this issue, this paper aims to provide an overview of potential alternative uses of different biogas feedstocks being researched in literature. We conducted a literature review using the machine learning technique “co-occurrence analysis of terms”. This technique reads thousands of abstracts from literature and records when pairs of biogas feedstock-application are co-mentioned. These pairs are assumed to represent the use of a feedstock for an application. We reviewed 109 biogas feedstocks and 217 biomass applications, revealing 1053 connections between them in nearly 55,000 scientific articles. Our results provide two insights. First, a large share of the biomass streams presently considered in the biogas estimates have many alternative uses, which likely limit their contribution to future biogas production. Second, there are streams not being considered in present estimates for biogas production although they have the proper characteristics. Full article

(This article belongs to the Special Issue Biomass Wastes for Energy Production)

► Show Figures

Figure 1

16 pages, 2369 KiB

Open AccessArticle

Life-Cycle Assessment of the Use of Peach Pruning Residues for Electricity Generation

by Jan Den Boer, Arkadiusz Dyjakon, Emilia Den Boer, Daniel García-Galindo, Techane Bosona and Girma Gebresenbet

Energies 2020, 13(11), 2734; https://doi.org/10.3390/en13112734 - 29 May 2020

Cited by 9 | Viewed by 2891

Abstract

Biomass residues from permanent crops might be an alternative fuel for energy generation in a local market with limited transport distances. Moreover, as activities related to CO₂ reduction are of special attention in the European Union (EU), sustainable use of resources plays [...] Read more.

Biomass residues from permanent crops might be an alternative fuel for energy generation in a local market with limited transport distances. Moreover, as activities related to CO₂ reduction are of special attention in the European Union (EU), sustainable use of resources plays an important role in climate change mitigation. In this paper, a life-cycle assessment (LCA) of the integrated value chain from peach pruning residues for electricity generation is presented and compared with the common practice including the mulching process of the pruned biomass in an orchard. It was shown that biomass harvesting, chipping and its delivery to a power plant—the Pruning-to-Energy (PtE) scenario—is feasible from an environmental point of view. The total global warming potential (GWP) of this value chain was 200 kg CO₂ eq.·ha⁻¹ (or 27 kg CO₂ eq.·GJ⁻¹). In turn, the mulching and leaving of the pruned biomass in an orchard—the pruning-to-soil (PtS) scenario—is characterized by a CO₂ equivalent of 2360 kg·ha⁻¹. Other impact categories showed a lower environmental impact for the PtE scenario as well. When considering the Spanish electricity-mix instead of coal-based electricity, the PtS scenario score better in most impact categories, but the GWP for the PtE scenario remains lower. Full article

(This article belongs to the Special Issue Biomass Wastes for Energy Production)

► Show Figures

Graphical abstract

12 pages, 1118 KiB

Open AccessArticle

Generalized Energy and Ecological Characteristics of the Process of Co-Firing Coal with Biomass in a Steam Boiler

by Joachim Kozioł, Joanna Czubala, Michał Kozioł and Piotr Ziembicki

Energies 2020, 13(10), 2634; https://doi.org/10.3390/en13102634 - 21 May 2020

Cited by 4 | Viewed by 1957

Abstract

One of the ways used to reduce the emission of carbon dioxide and other harmful substances is the implementation of biomass co-firing processes with coals. Such processes have been implemented for many years throughout many countries of the world, and have included using [...] Read more.

One of the ways used to reduce the emission of carbon dioxide and other harmful substances is the implementation of biomass co-firing processes with coals. Such processes have been implemented for many years throughout many countries of the world, and have included using existing high-power coal boilers. Despite numerous experiments, there are still no analyses in the literature allowing for their generalization. The purpose of this paper is to determine the generalized energy and ecological characteristics of dust steam boilers co-firing hard coal with biomass. The energy characteristics determined in the paper are the dependence of the gross energy efficiency of boilers on such decision parameters as their efficiency and the share of biomass chemical energy in fuel. However, the ecological characteristics are the dependence of emission streams: CO, NO_x, SO₂, and dust on the same decision parameters. From a mathematical point of view, the characteristics are approximation functions between the efficiency values obtained from the measurements and the emission streams of the analysed harmful substances and the corresponding values of the decision parameters. Second-degree polynomials are assumed in this paper as approximation functions. Therefore, determining the characteristics came down to determining the constant coefficients occurring in these polynomials, the so-called structural parameters. The fit of the determined characteristics was assessed based on the coefficients of random variation and the test of estimated significance of structural parameters. Boiler characteristics can be used when forecasting the impact of changes in operating conditions on the effects achieved in existing, modernized, and designed boilers. The generalization of the characteristics was obtained from the measurement results presented in 10 independent sources used to determine them. Full article

(This article belongs to the Special Issue Biomass Wastes for Energy Production)

► Show Figures

Figure 1

15 pages, 2448 KiB

Open AccessArticle

Syngas Production, Clean-Up and Wastewater Management in a Demo-Scale Fixed-Bed Updraft Biomass Gasification Unit

by Gabriele Calì, Paolo Deiana, Claudia Bassano, Simone Meloni, Enrico Maggio, Michele Mascia and Alberto Pettinau

Energies 2020, 13(10), 2594; https://doi.org/10.3390/en13102594 - 20 May 2020

Cited by 34 | Viewed by 4271

Abstract

This paper presents the experimental development at demonstration scale of an integrated gasification system fed with wood chips. The unit is based on a fixed-bed, updraft and air-blown gasifier—with a nominal capacity of 5 MW_th—equipped with a wet scrubber for syngas [...] Read more.

This paper presents the experimental development at demonstration scale of an integrated gasification system fed with wood chips. The unit is based on a fixed-bed, updraft and air-blown gasifier—with a nominal capacity of 5 MW_th—equipped with a wet scrubber for syngas clean-up and an integrated chemical and physical wastewater management system. Gasification performance, syngas composition and temperature profile are presented for the optimal operating conditions and with reference to two kinds of biomass used as primary fuels, i.e., stone pine and eucalyptus from local forests (combined heat and power generation from this kind of fuel represents a good opportunity to exploit distributed generation systems that can be part of a new energy paradigm in the framework of the circular economy). The gasification unit is characterised by a high efficiency (about 79–80%) and an operation stability during each test. Particular attention has been paid to the optimisation of an integrated double stage wastewater management system—which includes an oil skimmer and an activated carbon adsorption filter—designed to minimise both liquid residues and water make-up. The possibility to recycle part of the separated oil and used activated carbon to the gasifier has been also evaluated. Full article

(This article belongs to the Special Issue Biomass Wastes for Energy Production)

► Show Figures

Graphical abstract

19 pages, 6662 KiB

Open AccessArticle

Alternative Fuels from Forestry Biomass Residue: Torrefaction Process of Horse Chestnuts, Oak Acorns, and Spruce Cones

by Arkadiusz Dyjakon and Tomasz Noszczyk

Energies 2020, 13(10), 2468; https://doi.org/10.3390/en13102468 - 14 May 2020

Cited by 23 | Viewed by 3308

Abstract

The global energy system needs new, environmentally friendly, alternative fuels. Biomass is a good source of energy with global potential. Forestry biomass (especially wood, bark, or trees fruit) can be used in the energy process. However, the direct use of raw biomass in [...] Read more.

The global energy system needs new, environmentally friendly, alternative fuels. Biomass is a good source of energy with global potential. Forestry biomass (especially wood, bark, or trees fruit) can be used in the energy process. However, the direct use of raw biomass in the combustion process (heating or electricity generation) is not recommended due to its unstable and low energetic properties. Raw biomass is characterized by high moisture content, low heating value, and hydrophilic propensities. The initial thermal processing and valorization of biomass improves its properties. One of these processes is torrefaction. In this study, forestry biomass residues such as horse chestnuts, oak acorns, and spruce cones were investigated. The torrefaction process was carried out in temperatures ranging from 200 °C to 320 °C in a non-oxidative atmosphere. The raw and torrefied materials were subjected to a wide range of tests including proximate analysis, fixed carbon content, hydrophobicity, density, and energy yield. The analyses indicated that the torrefaction process improves the fuel properties of horse chestnuts, oak acorns, and spruce cones. The properties of torrefied biomass at 320 °C were very similar to hard coal. In the case of horse chestnuts, an increase in fixed carbon content from 18.1% to 44.7%, and a decrease in volatiles from 82.9% to 59.8% were determined. Additionally, torrefied materials were characterized by their hydrophobic properties. In terms of energy yield, the highest value was achieved for oak acorns torrefied at 280 °C and amounted to 1.25. Moreover, higher heating value for the investigated forestry fruit residues ranged from 24.5 MJ·kg⁻¹ to almost 27.0 MJ·kg⁻¹ (at a torrefaction temperature of 320 °C). Full article

(This article belongs to the Special Issue Biomass Wastes for Energy Production)

► Show Figures

Graphical abstract

16 pages, 1783 KiB

Open AccessArticle

Evaluation of Anaerobic Digestion of Dairy Wastewater in an Innovative Multi-Section Horizontal Flow Reactor

by Marcin Dębowski, Marcin Zieliński, Marta Kisielewska and Joanna Kazimierowicz

Energies 2020, 13(9), 2392; https://doi.org/10.3390/en13092392 - 11 May 2020

Cited by 35 | Viewed by 3200

Abstract

The aim of this study was the performance evaluation of anaerobic digestion of dairy wastewater in a multi-section horizontal flow reactor (HFAR) equipped with microwave and ultrasonic generators to stimulate biochemical processes. The effects of increasing organic loading rate (OLR) ranging from 1.0 [...] Read more.

The aim of this study was the performance evaluation of anaerobic digestion of dairy wastewater in a multi-section horizontal flow reactor (HFAR) equipped with microwave and ultrasonic generators to stimulate biochemical processes. The effects of increasing organic loading rate (OLR) ranging from 1.0 g chemical oxygen demand (COD)/L·d to 4.0 g COD/L·d on treatment performance, biogas production, and percentage of methane yield were determined. The highest organic compounds removals (about 85% as COD and total organic carbon—TOC) were obtained at OLR of 1.0–2.0 g COD/L·d. The highest biogas yield of 0.33 ± 0.03 L/g COD removed and methane content in biogas of 68.1 ± 5.8% were recorded at OLR of 1.0 g COD/L·d, while at OLR of 2.0 g COD/L·d it was 0.31 ± 0.02 L/COD removed and 66.3 ± 5.7%, respectively. Increasing of the OLR led to a reduction in biogas productivity as well as a decrease in methane content in biogas. The best technological effects were recorded in series with an operating mode of ultrasonic generators of 2 min work/28 min break. More intensive sonication reduced the efficiency of anaerobic digestion of dairy wastewater as well as biogas production. A low nutrient removal efficiency was observed in all tested series of the experiment, which ranged from 2.04 ± 0.38 to 4.59 ± 0.68% for phosphorus and from 9.67 ± 3.36 to 20.36 ± 0.32% for nitrogen. The effects obtained in the study (referring to the efficiency of wastewater treatment, biogas production, as well as to the results of economic analysis) proved that the HFAR can be competitive to existing industrial technologies for food wastewater treatment. Full article

(This article belongs to the Special Issue Biomass Wastes for Energy Production)

► Show Figures

Figure 1

18 pages, 1676 KiB

Open AccessArticle

Experimental and Modeling Analysis of Brewers´ Spent Grains Gasification in a Downdraft Reactor

by Sérgio Ferreira, Eliseu Monteiro, Luís Calado, Valter Silva, Paulo Brito and Cândida Vilarinho

Energies 2019, 12(23), 4413; https://doi.org/10.3390/en12234413 - 20 Nov 2019

Cited by 25 | Viewed by 2915

Abstract

The first part of the current reported work presents experimental results of brewers’ spent grains gasification in a pilot-scale downdraft gasifier. The gasification procedure is assessed through various process characteristics such as gas yield, lower heating value, carbon conversion efficiency, and cold gas [...] Read more.

The first part of the current reported work presents experimental results of brewers’ spent grains gasification in a pilot-scale downdraft gasifier. The gasification procedure is assessed through various process characteristics such as gas yield, lower heating value, carbon conversion efficiency, and cold gas efficiency. Power production was varied from 3.0 to 5.0 kWh during the gasification experiments. The produced gas was supplied to an internal combustion engine coupled to a synchronous generator to produce electricity. Here, 1.0 kWh of electricity was obtained for about 1.3 kg of brewers’ spent grains pellets gasified, with an average electrical efficiency of 16.5%. The second part of the current reported work is dedicated to the development of a modified thermodynamic equilibrium model of the downdraft gasification to assess the potential applications of the main Portuguese biomasses through produced gas quality indices. The Portuguese biomasses selected are the main representative forest residues (pine, eucalyptus, and cork) and agricultural residues (vine prunings and olive bagasse). A conclusion can be drawn that, using air as a gasifying agent, the biomass gasification provides a produced gas with enough quality to be used for energy production in boilers or turbines. Full article

(This article belongs to the Special Issue Biomass Wastes for Energy Production)

► Show Figures

Figure 1

32 pages, 7316 KiB

Open AccessArticle

Waste to Carbon: Biocoal from Elephant Dung as New Cooking Fuel

by Paweł Stępień, Kacper Świechowski, Martyna Hnat, Szymon Kugler, Sylwia Stegenta-Dąbrowska, Jacek A. Koziel, Piotr Manczarski and Andrzej Białowiec

Energies 2019, 12(22), 4344; https://doi.org/10.3390/en12224344 - 14 Nov 2019

Cited by 28 | Viewed by 5859

Abstract

The paper presents, for the first time, the results of fuel characteristics of biochars from torrefaction (a.k.a., roasting or low-temperature pyrolysis) of elephant dung (manure). Elephant dung could be processed and valorized by torrefaction to produce fuel with improved qualities for cooking. The [...] Read more.

The paper presents, for the first time, the results of fuel characteristics of biochars from torrefaction (a.k.a., roasting or low-temperature pyrolysis) of elephant dung (manure). Elephant dung could be processed and valorized by torrefaction to produce fuel with improved qualities for cooking. The work aimed to examine the possibility of using torrefaction to (1) valorize elephant waste and to (2) determine the impact of technological parameters (temperature and duration of the torrefaction process) on the waste conversion rate and fuel properties of resulting biochar (biocoal). In addition, the influence of temperature on the kinetics of the torrefaction and its energy consumption was examined. The lab-scale experiment was based on the production of biocoals at six temperatures (200–300 °C; 20 °C interval) and three process durations of the torrefaction (20, 40, 60 min). The generated biocoals were characterized in terms of moisture content, organic matter, ash, and higher heating values. In addition, thermogravimetric and differential scanning calorimetry analyses were also used for process kinetics assessment. The results show that torrefaction is a feasible method for elephant dung valorization and it could be used as fuel. The process temperature ranging from 200 to 260 °C did not affect the key fuel properties (high heating value, HHV, HHV_daf, regardless of the process duration), i.e., important practical information for proposed low-tech applications. However, the higher heating values of the biocoal decreased above 260 °C. Further research is needed regarding the torrefaction of elephant dung focused on scaling up, techno-economic analyses, and the possibility of improving access to reliable energy sources in rural areas. Full article

(This article belongs to the Special Issue Biomass Wastes for Energy Production)

► Show Figures

Graphical abstract

Journal Menu

Journal Browser

Biomass Wastes for Energy Production

Share This Special Issue

Special Issue Editor

Special Issue Information

Keywords

Published Papers (11 papers)

Editorial

Research

Further Information

Guidelines

MDPI Initiatives

Follow MDPI