Production of solid biofuel granules from drum granulation of bio-waste with silicate-based binders

Abstract

Herein compost was selected as a model bio-waste substrate to make solid biofuel granules using wet drum granulation and a sodium silicate binder. Using a laboratoryscale drum granulator (300 g/batch), spherical compost granules within the targeted size range (3.35-14 mm) could be produced with a good compressive strength in good to excellent yields. The effects of compost moisture content, process parameters (drum speed, granulation time) and binder parameters (binder concentration, binder to compost ratio) on the properties of the resulting granules (size distribution, bulk density, compressive strength, water resistance, gross calorific value, ash content) were investigated. The optimal conditions for producing granules as a solid biofuel with competitive properties when compared with woody biomass fuels were achieved by applying a drum rotational speed of 32-37 rpm, granulation time of 15 min, sodium silicate solution 1-3 wt% and binder to solid ratio 0.77-0.90.

Production of bio-waste granules and their evaluation as adsorbent for removal of hexavalent chromium and methylene blue dye

“…Granules that were produced in our previous work were used in this study [12]. Briefly, the granules are produced from biomass material (using compost as model biomass) in a drum granulator with a length of 0.65m and an internal diameter of 0.38m.…”

“…The granulation time was also kept constant at 15 minutes. For more details please see reference [12]. The batches will be named using this nomenclature SX where X is percentage concentration of sodium silicate in the binder so for example for batch produced with a 3% sodium silicate binder the batch or sample ID will be S3 whereas if no sodium silicate was in the binder it will be referred to as S0.…”

“…After granulation and drying of the granules, the granules were characterised in terms of size distribution, strength, and product yield and water resistance. More details on the analysis can be found in ref [12].…”

“…Among these reports, organic binders are commonly used for biomass agglomeration. Recently, in our research group, Chen et al produced the compost granules by using inorganic silicate-based binders and the produced granules had a good ability of water resistance [12]. It was reported that the silicate-based binders do offer higher performance in strength and water resistance of agglomerates [13], for the adsorption process, such water resistance ability can offer significant advantages over the other water-soluble binders.…”

Obtaining Granules from Waste Tannery Shavings and Mineral Additives by Wet Pulp Granulation

“…They also offer a higher level of binding performance such as strength, durability, and water resistance [ 44 ]. In a further study [ 45 ], the authors investigated the possibility of using a sodium silicate solution in a drum granulation process for the production of bio-waste granules. Compost was successfully densified into good-quality spherical granules for the purpose of convenient storage and transportation.…”