Industrial gas purification — What is the Vetrocoke solution used for acid-gas (CO2/H2S) absorption composed of?

Introduction:
Vetrocoke (also known from the Giammarco–Vetrocoke process) is a classic chemical absorption solvent used in gas purification plants to remove acidic gases such as carbon dioxide and hydrogen sulfide from synthesis gas and refinery streams. Knowing the exact composition helps distinguish it from other hot carbonate or amine systems.

Given Data / Assumptions:

• Question asks specifically for the composition of the Vetrocoke solution.
• Context is acid-gas removal in syngas processing and ammonia/urea plants.
• We compare with other families: hot carbonate (Benfield), amines (MEA/DEA), and alkaline salts.

Concept / Approach:

Vetrocoke is based on aqueous potassium carbonate (K2CO3) and historically included arsenic trioxide (As2O3) as a promoter/inhibitor package to enhance absorption kinetics and suppress catalyst poisoning/foaming. This differentiates it from the Benfield process (K2CO3 activated with amines like DEA or piperazine) and from primary/secondary amine systems like MEA/DEA which contain no carbonate salt as the primary base.

Step-by-Step Solution:

Verification / Alternative check:

Process design references list Vetrocoke as potassium carbonate with arsenic trioxide additives, whereas Benfield is potassium carbonate with organic amine activators. Plant licensing literature preserves this distinction historically.

Why Other Options Are Wrong:

B/D: Sulfates (K2SO4, Na2SO4) are neutral salts, not absorption solvents. C: Sodium carbonate with arsenic is not the named Vetrocoke formulation. E: Amine-activated hot carbonate exists (Benfield), but that is not Vetrocoke.

Common Pitfalls:

Confusing Vetrocoke with other hot carbonate technologies; always check the promoter package and base salt identity.

Final Answer:

a mixture of K2CO3 and As2O3