Question

4. In order to meet pollution standards, oil refineries remove trace amounts of sulfur from the crude oil. This sulfur is often in the form of H2S and SO2. A process has been suggested to convert these compounds into sulfur and water using the following reaction: 2H,ste)+S0,(g)- 3s6)+2H,og) A schematic of the facility is shown below. Due to the difficulty (and cost) of achieving high purity, the input streams (Fi and F2) both contain significant concentrations of CO2. The input feeds (Fi and F2) are blended to achieve a stoichiometric ratio of H2S and SO2 and are subsequently combined with a recycle stream and fed into the reactor. The solid sulfur is completely removed in the solids separator while the water is completely removed in a condenser. The stream leaving the condenser splits into a purge stream and the recycle stream. The flow rate in F1 is 100 mol/sec and the process achieves a 95% conversion of H2S. In addition, the recycle to feed ratio is R/Fo-15. What is the purpose of the recycle stream? What is the purpose of the purge stream? What is the flow rate at Fo? Please include the overall flow rate and the individual component flow rates. What are the flow rates of the recycle stream (R), solid sulfur stream (S), and water from the condenser (W)? Where appropriate, please include the overall flow rates and the individual component flow rates a) b) c) d) e) What percentage of the gas leaving the condenser is purged? f) What is the single pass conversion of the reactor? g) Discuss possible reasons why the single pass conversion is low h) Discuss at least 2 possible strategies to increase the overall conversion of the process F. 90.0% H2S 10.0% CO2 AR Fo Solids removal Water rermoval Reactor 95 096 SO2 5.00% CO2

Answer 1