Table 1.

Briquetting machine with their features, merits, and demerits

Machine type	Image	Features	Merits	Demerits	References
Piston press		Feedstock is compressed into a die by a to and fro moving ram Extrusion is done by the reciprocating piston Produced briquettes are usually with a concentric hole High-pressure type	Efficient and uniform combustion due to larger surface area Robust with a reputation of long working life They are simply maintained Less wear and tear Power consumption is minimal	Require frequent maintenance Cannot be used to manufacture carbonized briquettes Produced briquettes are not homogeneous	Sharma et al. (2015), Young and Khennas (2003), Ghaffar et al. (2015)
Screw press		Continuously extrude feedstock via an externally heated taper dye Extrusion is done using a specially designed screw Produced briquettes are completely solid Regular, homogeneous, and can withstand greater impact force without crumble High-pressure type	Generate less noise Used for both carbonized and non-carbonized briquettes Produced briquettes of high quality Briquettes are homogeneous and suitable for gasifier	High tear and wear High power consumption Required specific feedstock properties	Tuates et al. (2016a), Grover and Mishra (1996a), Young and Khennas (2003), Ghaffar et al. (2015) With permission
Hydraulic piston press		Driven by an electric motor via a hydraulic system low-pressure type	Light and compacted It can briquettes feedstock with higher moisture content	Slower with lower outputs Usually have a smaller bulk density	Grover and Mishra (1996a), Young and Khennas (2003), Shuma and Madyira (2019)