Search

The expediency of applying the test methods for sinter and pellets to determine the mechanical strength of blast-furnace briquettes is considered. Based on numerical modeling, the behaviors of pellets and briquettes under shock and abrasive loads in a rotating drum, static compressive loads, and when dropped from a height are compared. It is shown that due to the fundamental difference in the physical and mechanical properties of agglomerated products, corrections are needed for adequate assessment of the mechanical strength by conventional methods. Numerical modeling reveals a significant difference in the maximum stresses in a pellet and a briquette in the charge, which justifies the decrease in the compressive strength rejection limits for briquettes. When testing briquettes in a drum, their behavior when dropped on a metal surface should be taken into account. The rejection limits for testing briquettes in a drum should be adjusted. It is substantiated that the drop strength test method is fundamentally important for assessing the strength of blast-furnace briquettes because it is the most appropriate to the way they are delivered to the blast furnace. For the first time, the need to test briquettes for strength when exposed to gas flow is indicated. [ABSTRACT FROM AUTHOR]

The goal of this study was to develop briquettes from coffee and rice husks agricultural wastes as sustainable fuel sources for domestic cooking applications. Clay and cassava starch were used as binders. Physical properties of the coffee husks and rice husks as well as the developed briquettes were determined using Thermogravimetric analysis. Higher heating value (HHV) results were determined using bomb calorimetry. Drop test method was used to determine the mechanical and storage integrity of the developed briquettes. The results showed that the type of binder used in the development of the briquettes significantly affected both their physical properties and calorific values. Average higher heating values for briquettes developed with cassava starch binder ranged from 21.9 to 23.0 MJ/kg for coffee husks and 15.9–16.6 MJ/kg for rice husks. For coffee and rice husk briquettes developed with clay binder, average higher heating values ranged from 13.0 to 19.5 MJ/kg and 9.5–13.8 MJ/kg, respectively. Generally, cassava starch binder imparted higher drop strengths (over 95%) onto the briquettes than clay binder material. The characteristics were influenced by the physical properties of the raw biomass material as well as the high SiO 2 ash in the clay binder. [ABSTRACT FROM AUTHOR]

In this study groundnut shells and bagasse briquettes from agricultural wastes were developed with cassava and wheat starch binders using low pressure and high pressure techniques. In the low pressure technique, briquettes were produced after carbonization of groundnut shells and bagasse. The resulting bio-char was mixed with 30, 50, 70 and 90 g of cassava and wheat flour starch binder for each 1000 g of groundnut shells and bagasse bio-char. Groundnut shell briquettes were also developed under high pressure (230 MPa) using groundnut shells (1000 g) without a binder, groundnut shells (1000 g) with cassava flour starch binder (250 g) and groundnut shells with wheat flour starch binder (250 g). Thermo-physical properties of the briquettes were determined using thermo-gravimetric analysis. A Bomb calorimeter was used to determine the higher heating values of the briquettes. Thermal characteristics were determined by observing the flame temperature during combustion. The mechanical integrity of the briquettes was determined using the drop test method. The higher heating values for groundnut shell and bagasse briquettes developed using low pressure techniques were between 21 and 23 MJ/kg for both cassava and wheat starch binders. The results were all above the 16 MJ/kg average recorded for non-carbonized groundnut shell briquettes developed under high pressure. [ABSTRACT FROM AUTHOR]