Effect of starch binder on charcoal briquette properties

Abstract

A b s t r a c t. The paper shows the results of a study on the effect of starch binder on the mechanical, physical and burning properties of charcoal briquettes. Two types of binders were repeatedly used to make briquettes of native wheat starch and modified wheat starch, at 8% of the whole. Briquetting was performed in a roller press unit, and pillow-shaped briquettes were made. The moisture of the mixed material ranged from 28 to 32%. The product, whether the former or the latter, was characterized by very good mechanical properties and satisfactory physical properties. Moreover, the type of starch binder had no effect on toughness, calorific heating value, volatiles, fixed carbon content and ash content. However, the combustion test showed quite different burning properties. As briquettes should have short firing up time and lower smokiness, as well as high maximum temperature and long burning time, we have concluded that briquettes with native wheat starch as a binder are more appropriate for burning in the grill.K e y w o r d s: charcoal briquette, starch binder, burning INTRODUCTIONCharcoal fuel has many attractive features: it contains almost no sulfur or mercury and is low in nitrogen and ash, in addition, it is easy to store and handle (Antal and Grønli, 2003). Further technical and economic aspects of fine coal and charcoal briquettes have been evaluated because of the binder and briquetting parameters. Briquetting pressure and dwell time have a weak impact, while binder type and curing conditions exert the greatest influence on briquettes quality (Borowski and Hycnar, 2013;Taulbee et al., 2009). What is more, mechanical properties increase with time of curing at room temperature of carbonized-coal briquettes (Blesa et al., 2003).Binders such as molasses, starch, tar, etc. are added to produce fuel briquettes, and the addition of starch binder, as well as gum Arabic binder improves the caloric value of biofuel briquettes (Zakari et al., 2013). Physical properties such as density, compressive strength and impact resistance index of briquettes also show significant improvement because of binders (Sen et al., 2016). Further additives are inorganic fillers which delay the heat release of the burning briquette, and ignition enhancers, which promote greater combustibility. Charcoal briquettes are promoted as substitutes for natural coal, petroleum coke or lignite. Still, the advantages of charcoal fuel depend on important factors: low sulphur content, high carbon to ash ratio, relatively few and nonreactive inorganic impurities, specific pore structure with large surface area, good reduction ability, almost smokeless emissions (Emrich, 1985). The disadvantages of charcoal fuel are clearly seen when compared to liquefied petroleum gas (LPG) fuel. The charcoal grilling footprint of CO 2 is almost three times larger than for LPG combustion. In addition, LPG is radically more efficient than charcoal in its production, and considerably more efficient in cooking. However, the use of LPG requires a heavier and more...

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