Design performance evaluation of mechanical single-position briquetting machine for making briquettes from rice milling by-products

The study developed a mechanical single-piston briquetting machine to process rice hull in NFA Camarines Sur [Philippines] branch. Four mixtures for making briquettes namely: Control (94% CRH, 6% cassava starch), Treatment 1, T1 (75% CRH, 25% bran), Treatment 2, T2 (65% CRH, 35% bran) and Treatment 3, T3 (55% CRH, 45% bran) were used to test the performance of the machine. The quality of the produced briquettes were also analyzed. The briquetting capacity for Control, T1, T2, and T3 were 15.69 kg/hr, 14.72 kg/hr., 20.35 kg/hr and 22.01 kg/hr. It shows that the bran content in the mixture was proportional to its capacity because of the density. The briquetting efficiency of Control, T1, T2, and T3 were 98.18%, 95.39%, 95.52%, and 96.16% respectively. These results show no significant difference among the treatments which concludes that the binder used does not affect the machine ability to form briquettes. The briqueting recovery of the Control, T1, T2. and T3 were 96.91%, 83.58%. 95.52%, and 95.56% respectively. It shows that the binder is crucial in obtaining high recovery in making briquettes. The diameter coefficient of variance was 1.2. It means that the machine is reliable to produce desired diameter at any given time. The moisture content and density of all the produced briquettes both meet the guiding value of less than or equal to 12% and 0.50 g/cc respectively. The MC of Control, T1, T2, and T3 were 6.86%. 7.29%, 7.57%, and 8.53 %, respectively. The density of Control, T1, T2, and T3 were 0.50 g/cc, 0.52 g/cc, 0.52 g/cc, and 0.57 g/cc, respectively. The results of compression and durability of produced briquettes both have no statistically significant different among treatments. This signifies that the composition of raw material and the different percentage of bran component has no effect in the said properties of briquettes. However, both results of durability and compression is below the guiding value of 95% and 1.0 MPa. The durability of Control, T1, T2, and T3 were 62.61%. 76.58%, 72.55%, and 70.92%, respectively. The compression of Control, T1, T2, and T3 were 0.42 MPa. 0.47 MPa. 0.37 MPa, and 0.54 MPa, respectively. The heating value of produce briquettes show increase in value compare with raw rice hull with heating value of 3000 to 3500 cal/g (according to literature) and were also higher than the required heating value of 11.66 MJ/kg or 2786.81 cal/g to sustain combustion as define by Lee, 2007. The heating value for Control, T1, T2, and T3 were 3648.33 cal/g, 3741.67 cal/g 3680.00 cal/g and 3661.67 cal/g respectively. Considering the production process, cost in production and output briquette quality in the study, Treatment 2 shows many advantages and therefore it is reasonable to use this for comparison to similar product in the market. The calculated cost for this briquette is 39.20 pesos per kilogram. This resulting computed price was competitive in comparison to existing market price of briquettes that ranges from 40 to 55 pesos per kilogram.