Biomass A. is a carbon cycle neutral fuel B. has significantly higher…

2024

Biomass

A. is a carbon cycle neutral fuel

B. has significantly higher calorific value than coal

C. can be converted in solid, liquid and gaseous fuels

D. can be converted into Producer Gas

E. can not be obtained from energy crops

Choose the correct answer from the options given below:

Answer: B. A, C and D OnlyCONCEPTBiomass is organic matter of recent biological origin — wood, crop and agro-residue, animal waste, municipal organic waste and purpose-grown energy…

  1. A.

    A, B and C Only

  2. B.

    A, C and D Only

  3. C.

    B, D and E Only

  4. D.

    A, B and E Only

Show answer & explanation

Correct answer: B

CONCEPT

Biomass is organic matter of recent biological origin — wood, crop and agro-residue, animal waste, municipal organic waste and purpose-grown energy crops — used as fuel. Its carbon was drawn out of the air by photosynthesis during the current growth cycle, so burning it returns carbon that the same cycle had just removed; that closed short-term loop is what "carbon cycle neutral" means, and it is what separates biomass from fossil fuels, whose carbon has been locked away for geological time.

Two further properties follow from what biomass physically is. Because it carries a high moisture and oxygen content and a low fixed-carbon fraction, the heat released per kilogram is modest compared with coal. And because it is a reactive carbonaceous solid, it can be upgraded by thermochemical routes (densification, carbonisation, pyrolysis, gasification) and biochemical routes (fermentation, anaerobic digestion) into fuels in every physical state.

APPLICATION — testing each of the five claims

Claim about biomass

What the evidence shows

A. Carbon cycle neutral fuel

Stands. The CO2 released on combustion was fixed from the atmosphere by the plant in the current cycle, so no carbon is added to the active pool over the crop-and-burn loop.

B. Calorific value significantly higher than coal

Fails. Air-dried wood and crop residue deliver roughly 15–19 MJ/kg, while bituminous coal delivers about 25–33 MJ/kg and anthracite still more. Biomass sits well below coal, not above it — its high moisture and oxygen content is exactly why.

C. Convertible into solid, liquid and gaseous fuels

Stands. Briquettes, pellets and charcoal are the solid fuels; bio-oil from pyrolysis, bioethanol from fermentation and biodiesel from transesterification are the liquid fuels; biogas, producer gas and syngas are the gaseous fuels.

D. Convertible into Producer Gas

Stands. Gasifying a carbonaceous solid in a deliberately restricted air supply yields producer gas — chiefly CO, H2 and N2 with a little CH4 — the classic route used in biomass gasifiers.

E. Cannot be obtained from energy crops

Fails. Energy crops are grown precisely to be biomass feedstock: sugarcane and maize for ethanol, jatropha and pongamia for biodiesel, and napier grass, bamboo, poplar and switchgrass for solid fuel and gasification.

CROSS-CHECK

The claims that survive scrutiny are carbon cycle neutrality, conversion into all three physical states of fuel, and conversion into producer gas — the set A, C and D. The two that fail are the calorific-value comparison (B), which reverses the true ordering against coal, and the energy-crop denial (E), which contradicts the entire purpose of an energy crop. Any grouping that carries B or E therefore cannot be the required set.

Required combination: A, C and D.

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