Major composition of biogas is: - Solved MCQ | Agrigyan

Steam economy of an evaporator is defined as the mass of water vaporized per unit mass of live steam supplied: $\text{Economy} = \frac{\text{Mass of water evaporated}}{\text{Mass of steam consumed}} = \frac{1500\text{ kg/h}}{2000\text{ kg/h}} = 0.75$. (For a single-effect evaporator, economy is typically $\lt 1.0$). Option analysis: (A) $0.75$ is the exact calculated evaporator economy. (B) $1.0$ is theoretical maximum for ideal single effect. (C) $1.33$ inverts steam and water. (D) $3.0$ is characteristic of triple-effect evaporators.

All four are recognized scientific moisture determination methods: (A) Brown-Duvel is a standard distillation method boiling grain in oil. (B) Dielectric method is an indirect electronic method measuring capacitance/dielectric constant. (C) Chemical method includes Karl Fischer titration and calcium carbide methods. (D) Infra-red method measures moisture via infrared absorption or infrared moisture balance heating. Option analysis: (A) Omits chemical method. (B) (A), (B), (C) and (D) includes all valid moisture methods. (C) Omits distillation. (D) Omits infrared.

Food extrusion is a high-temperature short-time (HTST) bioreactor processing technique that integrates conveying, mixing, kneading, shearing, cooking/plasticizing, and shaping/texturing through a restricted die into a single continuous automated unit operation. Option analysis: (A) Extrusion combines all these mechanical and thermal unit operations. (B) Cold sterilization refers to radiation or filtration preservation. (C) Irradiation uses ionizing radiation for pathogen reduction. (D) Sous vide is vacuum pouch low-temperature cooking.