The Impact of Particles Comminution on Mechanical Durability of Wheat Straw Briquettes

Abstract

Briquetting is one of the recommended biomass agglomeration processes. The material subjected to briquetting gains valuable functional features related to higher energy density, appropriate moisture content, and increased bulk density. However, the briquettes need high mechanical durability to maintain high quality during transportation, loading, and other logistic steps before they will be delivered to the final consumer and utilized for energy purposes. The mechanical durability depends on many factors, including the particles comminution of the compacted biomass. Therefore, the aim of this study was to analyze the impact of particle comminution on the mechanical durability of wheat straw briquettes. The research was carried out in accordance with the international standard for solid biofuels PN-EN ISO 17831-1:2016-02. The briquettes were produced from three different fractions: 0–2 mm, 2–15 mm, and 15–45 mm. To obtain more data related to the mechanical durability of briquettes, the tests were also carried out outside the ISO standard conditions. During the investigations, the working chamber operation time was extended from 5 to 60 min, and the rotational speed of the working chamber was increased to 25 and 30 rpm, respectively. The results indicated that the mechanical durability index (Du) of briquettes decreases along with the increase in the particle size. According to the PN-EN ISO 17831-1:2016-02 standard, the highest mechanical durability was achieved for the 0–2 mm fraction (Du = 91.17%) followed by the 2–15 mm fraction (Du = 88.12%), and the lowest was achieved for the 15–45 mm fraction (Du = 84.48%). It was noticed that the increase in the working chamber operation time resulted in a decrease of the Du value. Moreover, the difference in mechanical durability (between t5 = 5 min and t60 = 60 min) was greater for a larger fraction (∆Du = 16.26% for 0–2 mm fraction, ∆Du = 21.04% for 2–15 mm fraction, and ∆Du = 23.43% for 15–45 mm fraction). It was also observed that the increase of the rotational speed of the working chamber caused a slight decrease in the value of the mechanical durability of briquettes for all investigated fractions.

A Review of Biomass Briquette Binders and Quality Parameters

“…Irrespective of the equipment used, researchers often use different rotational speeds and different sieve sizes to obtain the mass loss, making it difficult to compare reported values. An increase or decrease in operation time and rotational speed of the working chamber of durability devices, for example, could influence the durability of briquettes [130]. Temmerman, et al [131], in an earlier study comparing the durability of densified briquettes, reported that the durability of briquettes was influenced by measurement methods.…”

Values of Selected Strength Parameters of Miscanthus × Giganteus Stalk Depending on Water Content and Internode Number

“…The percentage share of cellulose, hemicellulose and lignin in a given type of biomass may vary, which significantly affects its energy parameters and the possibility of using it for the production of biofuels [5]. Depending on the origin of the biomass (classification according to ISO 17225-1:2014 [6]), research is carried out on woody [7][8][9], and herbaceous biomass [10,11], but also pomaces, fruit stones, kernel shells and other residuals [12][13][14][15], and recently on so-called water biomass, or algae, for example, hyacinths [16,17].…”

Dispersed Power Production in Terms of the Potential of Briquettes Made from Straw and Willow as Renewable Sources of Energy

“…As reported by Dyjakon et al in 2020 [ 14 ], one of the more important processes of biomass agglomeration is briquetting, and the material undergoing that process shows special performance features. Those special properties of briquettes are mostly related to the right moisture level, an increased bulk value, as well as a higher energy density.…”