Foliage and Grass as Fuel Pellets–Small Scale Combustion of Washed and Mechanically Leached Biomass

Sports fields provide a recreation space for citizens, but also generate grass biomass, which is cut weekly during the main seasons and therefore could be used in energy generation (combustion or anaerobic digestion). To evaluate the technical suitability of the grass cuttings, silage was produced from four sports fields during one vegetation period and investigated for relevant properties. Potential methane yield was determined with batch tests. Mean methane yield was 291.86 l N ·kg −1 VS added (VS, volatile solid). Neutral detergent fiber concentration was low (44.47% DM, dry matter), yet mineral concentration was high in comparison to grass types cut at a lower frequency. Concentrations of Cl, N, and S, which may lead to unfavorable emissions, fouling, and corrosion during combustion, were too high for an unproblematic combustion process. This was still the case even after applying a mineral-reducing pretreatment, which generates a fiber-rich press cake and a press fluid rich in easy soluble substances. Digestion of the press fluid led to methane yields of 340.10 l N ·kg −1 VS added and the press cake had a higher heating value of 19.61 MJ·kg −1 DM, which is close to that of coniferous wood. It can be concluded that biomass from sports fields could be a suitable co-substrate in bio-energy generation.

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“…Yet, Khalsa at al. [20] reported 2S/Cl ratios >10 for urban grass and leaf litter after a leaching process.…”

Section: Combustion Related Properties Of Silage and Press Cakementioning

confidence: 99%

Using Grass Cuttings from Sports Fields for Anaerobic Digestion and Combustion

2017

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“…Though combustion of leaf litter may be an efficient conversion process, ash concentration is a known problem, whether it is natural or caused by contamination due to collection, transport or storage. While leaf litter collected in urban parks showed average ash concentration of 13.8% dry matter (DM) [4] and 17.5% DM [5], values can be as high as 34.8% DM when collected from street and pavement surfaces in practice [6]. Removal of ash after combustion is costly and the various ash fractions (bottom ash, cyclone fly-ash and filter fly ash constituting 60%-90%, 10%-35% and 2%-10%, respectively, according to Van Loo and Koppejan [7]) need to be deposited or processed because of their content of hazardous elements (e.g., heavy metals, organic contaminants).…”

Section: Introductionmentioning

confidence: 99%

High-Quality Solid Fuel Production from Leaf Litter of Urban Street Trees

et al. 2016

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Leaf litter is a growing concern for cities. Due to adherent dirt such biomass is rarely utilized nowadays but may constitute a renewable energy source for communities or private households. Leaf litter from main roads, residential areas and city centres collected by the vacuum technique or the sweeper technique was sampled and analysed for ash content and chemical composition. Ash content of leaf litter collected by the sweeping technique was higher (21.6%-40.1% dry matter, DM) than in material collected by the vacuum technique (12.0%-21.7% DM). Leaf litter from residential areas had the highest contamination (21.7%-40.1% DM), followed by main roads (20.8%-26.2% DM) and city centres (12.0%-21.6% DM). Ash content was reduced by up to 60% with a washing treatment and reached values comparable to those achieved by multiple manual rinsing, which was conducted as a reference treatment. The chemical composition of washed leaf litter could be further improved by mechanical dehydration treatment due to a reduction in harmful elements for combustion such as K, Cl, Mg and S. Heating value of leaf litter increased and the risk of corrosion and ash melting during combustion were reduced.

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“…The HHVs found by Richter et al [31] were a bit lower, with 17.8 MJ·kg −1 DM for silages and 18.4 MJ·kg −1 DM for PC. While these values were calculated using the chemical composition of biomass, Khalsa et al [32] conducted measurements in a bomb calorimeter with leached biomass comparable to the IFBB PC described here. They found LHV values of 18.4, 18.9 and 18.2 MJ·kg −1 DM for leached grass, foliage and a 50%:50% mixture, which is only marginally higher than the calculated LHVs for L0, L25, L50, L75 and L100 (17.8, 17.9, 18.0, 18.0, and 18.0 MJ·kg −1 DM, respectively).…”

Section: Heating Valuementioning

confidence: 99%

The Effect of the Invasive Plant Species Lupinus polyphyllus Lindl. on Energy Recovery Parameters of Semi-Natural Grassland Biomass

Hensgen

Wachendorf

2016

Sustainability

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Biodiversity of semi-natural grasslands is increasingly endangered by successful invasive plant species such as the legume Lupinus polyphyllus Lindl. In order to contain the propagation of this plant species, early and regular harvesting needs to be applied. Therefore, a form of utilization for the harvested biomass has to be developed. One opportunity could be the use of the biomass as a feedstock for biogas and solid fuel production. This study investigates the effect of L. polyphyllus on the nutrient and mineral composition in a mixture series with semi-natural grassland biomass and examines the changes in nutrient and mineral content through hydrothermal conditioning and mechanical dewatering of silage. Untreated lupine-invaded biomass has higher N and Mg concentrations, but lower Cl, K and S concentrations compared to the semi-natural grassland biomass. The mineral concentrations in the biomass exceeded recommendations for combustion. However, with the proposed pre-treatment of hydrothermal conditioning and subsequent dewatering, both lupine-containing and lupine-free semi-natural grassland biomass could achieve adequate values for combustion, given that a state-of-the-art combustion technique is used, including measures to reduce emissions of NO x and particulate matter. Thus, solid fuel production through hydrothermal conditioning and mechanical separation may offer a practical solution for the containment of lupine or other invasive species in semi-natural grasslands and may constitute an important element for sustainable bioenergy production.

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Foliage and Grass as Fuel Pellets–Small Scale Combustion of Washed and Mechanically Leached Biomass

Cited by 32 publications

References 27 publications

Using Grass Cuttings from Sports Fields for Anaerobic Digestion and Combustion

Using Grass Cuttings from Sports Fields for Anaerobic Digestion and Combustion

High-Quality Solid Fuel Production from Leaf Litter of Urban Street Trees

The Effect of the Invasive Plant Species Lupinus polyphyllus Lindl. on Energy Recovery Parameters of Semi-Natural Grassland Biomass

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