Biochemical Conversion Technology

• Grain Storage Silo Classifications (Deep vs. Shallow Bins):
• Statement (I): In a deep bin, plane of rupture strikes the opposite side of structure before it meets the grain surface. $\implies$ True.
• In deep grain bins, the internal plane of rupture of the granular mass intersects the opposite vertical wall before reaching the top free surface of the grain.
• Statement (II): A grain bin can be classified as deep bin when the depth of grain is greater than the equivalent diameter. $\implies$ True.
• By Janssen and Airy criteria, a bin is classified as a deep bin when grain depth $H \gt D \tan(45^\circ + \phi/2) \approx D$.
• Conclusion: Both Statement (I) and Statement (II) are true (Option 1).

Correct option: (1) Both Statement (I) and Statement (II) are true.

• Factors Governing Air-Screen Grain Cleaner Capacity:
• An air-screen grain cleaner separates impurities based on aerodynamic drag (aspirator air duct) and particle dimensions (screens):
• Grain bed depth: Governs screen stratification and air passage.
• Size of screen surface: Width and length define total active screening area ($m^2$).
• Feeding mechanism: Ensures uniform, non-pulsing curtain flow across the full screen width.
• Percentage opening area of screen: Dictates open perforation fraction through which clean grain passes.
• Conclusion: Capacity depends on (A), (B), (C) and (D) (Option 3).

Correct option: (3) (A), (B), (C) and (D).

• Biodiesel Production via Transesterification:
• Chemical Reaction: Transesterification (alcoholysis) is the primary chemical process where triglycerides from plant oils (e.g., Jatropha, Pongamia, soybean) or animal fats react with a short-chain alcohol (methanol or ethanol) in the presence of an alkaline catalyst (KOH or NaOH):

• Objective: Converts high-viscosity triglycerides into low-viscosity fatty acid methyl esters (FAME), making the fuel compatible with compression-ignition (diesel) engines without injector coking.
• Conclusion: Trans-esterification (Option 3).

Correct option: (3) Trans-esterification