biomass briquettes production as sources of energy

biomass briquettes production

1. ANALYSIS OF BRIQUETTE MADE FROM SAW DUST, CHARCOAL AND RICE HUSK Okoh , E. V. C., Tukur , U. G. Bawa , V.,

2. ABSTRACT There are significantly high quantities of rice husk, sawdust and charcoal fines as by-products from the rice mills, wood milling and charcoal industries in most parts of Nigeria. These by-products are virtually being wasted and constituting environmental pollution. The aim of this study is the analysis of briquette made from saw dust, charcoal dust and rice husk as sustainable alternative energy sources. The proximate/ultimate analysis and physical properties of the briquettes were determined. From the results, it was found that, the Saw dust recorded the highest volatile matter (84.5%) with ash content of (8.35%), assuring a very high burning efficiency, while Charcoal has the lowest volatile matter (67.5%) and Rice husk has a Volatile matter of (79.5%) . The rice husk, charcoal and the saw dust briquettes respectively has (6.5%), (5.5%) and (10.5%) percentage moisture content though within the recommended limit (< 15%). The Charcoal briquettes have the highest value of fixed carbon of 27.45%, ranking it highest in heat generating capacity during burning time. The rice husk briquette has the highest density (1.1g/cm3) resulting to longest burning time among the briquettes produced in this research. The use of rice husk saw dust and charcoal as fuel briquettes can offer several advantages including, reduction of environmental pollution from the use of fossil fuels, and reduction of ecological disaster arising from deforestation.

3. 1.0 INTRODUCTION A briquette is a block carbonaceous material used as fuel to start and maintain fire, this process involves the densification of loose biomass residues, such as sawdust, straw, rice husk and charcoal fine into high density solid blocks that can be used as a fuel, common types of briquettes are charcoal and biomass briquettes, biomass briquettes (including pellets, which are very small briquettes), it replace fossil fuels or wood for cooking and industrial processes, they are cleaner and easier to handle, and cut greenhouse gas emissions (Maninder, et al. 2012).

4. 3.0 MATERIALS AND METHODS 3.3 Sample Collection and preparation The samples (charcoal and saw dust) were obtained from Saw Mills in Sokoto New Market, Sokoto State, Nigeria while the Rice Husk was obtained from Kalambaina rice Mills, Sokoto State. The samples were then brought to the laboratory of the Department of Pure and Applied Chemistry, Usmanu Danfodiyo University, Sokoto for physical, proximate and ultimate analysis.

5. 3.0 MATERIALS AND METHODS 3.4 Briquette Production The collected rice husk samples was screened from stones and other impurities that might inhibit proper briquette formation after which a sieve was used to obtain uniform size. The electric plate was switched on and water was poured into the kettle and placed on the heating mantle. After boiling, the hot water was mixed with the starch until a sticky gel was produced. The rice husk was wetted with water so as to enhance uniform mixing with the binding agent (Starch). The binder (starch) was then mixed with the wetted rice husk in the proper binder-mix ratio. This mixture was poured into the mould. With the effect of the pressure applied the rice husks were compressed and the briquettes were formed and removed from the mould, the same applied to each sample.

6. 3.0 MATERIALS AND METHODS 3.5.1 Physical Properties of the Briquettes The average maximum density of the briquettes from each sample was determined immediately after ejection from the mould and this was calculated as the ratio of the average mass to the volume of briquette. The mass was obtained by using a digital weighing scale, while the volume was calculated by taking the dimensions of the cylindrical briquettes (radius and height). By applying the formula for the volume of a cylinder (𝜋𝑅 2 𝐻), the volume of the formed briquette was obtained. The relaxed density of the briquettes from the sample was determined in the dry condition after drying in an oven dryer. It was calculated simply as the ratio of the briquette’s mass after drying to its volume. Relaxed density can be defined as the density of the briquette obtained after the briquette has remained stable. It is also known as spring back density.

7. 3.0 MATERIALS AND METHODS 3.5.2 Proximate Analysis of the Briquettes Proximate analysis, which is a standardized procedure that gives an idea of the bulk components that make up a fuel, was carried out to determine the average of the percentage volatile matter content, percentage ash content, moisture content and percentage content of fixed carbon of the briquettes obtained from four replicates. The procedures of the ASTM standard D5373-02 (2003) was adopted to obtain the following parameters:

8. 3.5.3 Ultimate Analysis of the Briquettes Estimations of important chemical elements that make up briquettes fuel, namely percentage carbon, hydrogen, oxygen, nitrogen and sulphur, will be determined through ‘ultimate' analysis. These properties were determined in accordance with American Standard Test and Methods (ASTM) analytical methods as prescribed by Jenkins et al., (1998).

9. 3.5.2.5 Water Boiling Test The water boiling test is a well-known test which has been previously used by many researchers including Yusuf et al (2021). It measures the time it takes a given quantity of fuel to heat and boil a given quantity of water. In this case a known quantity of briquettes from the three (3) samples was measured and stacked in three different stoves. The stoves were ignited and as soon as the flames were stabilized for 2 minutes, 3 aluminum kettle containing 1litre of water each were mounted on the stoves. The initial temperatures of the water were noted as 26 O C and a stop watch was activated and thereafter readings were obtained at 5 minutes interval using a thermometer, this was terminated after attaining boiling point

10. Parameters Rice Husk Saw dust Charcoal Height of briquette (cm) 8.00 8.00 8.00 Diameter of briquette (cm) 3.00 3.00 3.00 Mass of briquette (g) 250 220 230 Volume(cm 3 ) 226.1 226.1 226.1 Maximum Density(g/m 3 ) 1.105 0.973 1.017 Relaxed Density(g/m 3 ) 0.884 0.751 0.796 Colour Brown brown Black Texture rough rough fine 4.0 RESULT AND DISCUSSION 4.1 RESULT Table 4.1: Physical Properties of Rice Husk, Saw Dust and Charcoal Briquette  

11. Table 4.2: Proximate Composition of Rice Husk, Saw Dust and Charcoal Briquette Parameters Rice Husk Saw dust Charcoal Volatile matter (%) 76.5 81 62 Ash content (%) 12.4 6.0 5.05 Moisture Content (%) 3 5.5 5.5 Fixed carbon (%) 8.10 7.5 27.45 Heating Value(MJ/Kg) 15.17 16.19 18.38

12. Table 4.3: Ultimate Composition of Rice Husk, Saw Dust and Charcoal Briquette Parameters Rice Husk Saw dust Charcoal Carbon content (%) 45.20 42.90 64.30 Hydrogen content (%) 5.80 4.22 6.70 Oxygen content (%) 47.60 43.50 40.25 Nitrogen content (%) 1.02 1.07 1.19 Sulphur content (%) 0.21 0.29 0.37

13. Water boiling tests for Rice husk, Sawdust and Charcoal Briquettes. The initial temperature of water at each of the tree sample was recorded as 26 O C after 5minutes of heating the rice husk, sawdust and charcoal briquettes temperature increased to 58, 48 and 53 respectively,

14. Conclusion The physical characteristics, proximate and ultimate composition of the briquettes was determined and analyzed, the following conclusions were made:. Rice husk generated in large quantities from rice mills and saw dust which when burnt directly pollutes the environment can be converted into high-quality and durable solid fuel briquettes that will be suitable for both domestic and industrial energy production. The briquettes with a high volatile content can easily be ignited for combustion purposes. The high volatile matter content also indicated that during combustion briquettes were burn as gas in combustion chambers. The high heating value calculated for briquette produced from rice husk, saw dust and charcoal indicates that the briquettes can produce heat required for household cooking and small scale industrial applications. Also the briquettes produced are environmentally friendly due to the low nitrogen and sulphur contents .