Question

Hydrogen sulfide has the distinctive unpleasant odor associated with rotten eggs, and it is poisonous. It often must be removed from crude natural gas and is therefore a product of refining natural gas. In such instances, the Claus process provides a means of converting H2S to elemental sulfur. Consider a feed stream to a Claus process that consists of 10.0 mole% H2S and 90.0% CO2. One-third of the stream is sent to a furnace where the H2S is burned completely with a stoichiometric amount of air fed at 1 atm and 25°C. The combustion reaction is H 2 S + 3 2 O 2 → S O 2 + H 2 O The product gases from this reaction are then mixed with the remaining two-thirds of the feed stream and sent to a reactor in which the following reaction goes to completion: 2 H 2 S + S O 2 → 3 S + 2 H 2 O The gases leave the reactor at 10.0 m 3 / min , 320°C, and 205 kPa absolute. Assuming ideal-gas behavior, determine the feed rate of air in kmol/min. Provide a single balanced chemical equation reflecting the overall process stoichiometry. How much sulfur is produced in kg/min?

Answer 1

The Claus process involves burning one-third of hydrogen sulfide feed with oxygen to form sulfur dioxide and water, which then reacts with remaining hydrogen sulfide to produce elemental sulfur. The overall stoichiometry combines both reactions to show the relationship between reactants and products. The sulfur production can be calculated using the moles of hydrogen sulfide and the molar mass of sulfur.

Step-by-step explanation:

To calculate the feed rate of air in the Claus process for converting hydrogen sulfide (H2S) to elemental sulfur, we must first understand the stoichiometry of the reaction involved. Given that one-third of the stream is burned completely in the presence of oxygen, the initial stoichiometric combustion reaction in the furnace is H2S + 3/2 O2 → SO2 + H2O. Then, the product gases combine with the remaining two-thirds of the H2S feed stream to react fully according to the equation 2 H2S + SO2 → 3 S + 2 H2O.

The overall process stoichiometry, when combining both reactions, is 3 H2S + 3/2 O2 → 3 S + 3 H2O, showing that 3 moles of H2S react with 1.5 moles of O2 to produce 3 moles of sulfur and 3 moles of water.

To determine the sulfur production in kg/min, we must calculate the moles of H2S being processed and then use the molar mass of sulfur to convert moles to kilograms. The ideal gas law, along with the stream conditions given, could provide the necessary information to make this calculation.