化学代写 catalyst fundamentals and kinetics

Catalysis for Emission Control EA4550

Fall 2021: Exam #1

 Catalyst fundamentals and kinetics

化学代写 A professionally prepared electronic copy (in WORD) is due no later than Thursday 21 October Equations can be neatly hand written.

A professionally prepared electronic copy (in WORD) is due no later than Thursday 21 October

Equations can be neatly hand written.

Feel free to work in teams. Each member should draft their answers independently before meeting with the team to compromise your final submission

1. (total=5 points)

a. (3 points) Describe how you would make a Pd/Al₂O₃washcoated catalyst onto the walls of a ceramic monolith? The precursor is Pd(NO₃)₂

b. (2 points) What characterization instrument(s) would you use to determine the proper conditions for its final preparation? Why are these important?

2. (total = 6 points) 化学代写

A wire coating facility must abate toluene emissions (toluene is the liquid used to suspend the coating material). They hire a catalyst company, for which you work, to design the catalyst and operating process. Based on the company’s experience, a 1%Pt on Al₂O₃ washcoated monolith (1% Pt/Al₂O₃//400 cells per square inch (CPSI) monolith is recommended. Design some laboratory experiments (at least one for monolithic catalyst and at least one for the process condition)

1. Bulk Mass Transfer (2 points)
2. Pore Diffusion (2 points)
3. Chemical or Kinetic (2 points)

3. (total = 4 points) 化学代写

3a. (2 points) How are reaction orders for A and B determined in the rate equation below?

Consider Rate = kC_A^x C_B^y

3b. (2 points) Show one experimental method to determine the activation energy.

4. 4. (total=6 points) 化学代写

The first oxidation catalyst used in the US in 1975 for abating CO and HC emissions from the automobile exhaust (gasoline) was a combination of 2 1/2%Pt and 1%Pd dispersed on γ-Al₂O₃ on a monolith.  In Brazil, where ethanol (derived sugar cane) is often used as a fuel, the local catalyst companies first tried the same catalyst. The first laboratory conversion vs. temperature tests were conducted with a simulated feed gas ted emission of 2% ethanol in excess air. The ethanol began converting at 150^oC however, the product distribution (selectivity), especially at low temperatures, showed undesirable acetaldehyde (CH₃CHO) formation along with the desired CO₂ and H₂O.

4a. (2 points) Write the general rate equations for the formation of each product. Ignore the reverse reaction since the Ke is very large. The formation of acetaldehyde was determined to be first order in ethanol while for the CO₂ path the ethanol order was 0.25.  In both cases the O₂ was pseudo zero order because it was present in large excess. How can you use these kinetic parameters to enhance the desired reaction?

4b. (2 points) The CO₂ path has an activation of 80 kj/mol while the undesired path 45 Kj/mol. In the exhaust of the vehicle what could you consider dong to optimize the reactor design to minimize the undesired reaction?

4c.  (2 points) Given that the Pt, Pd catalyst has worked for gasoline engines but has a not so well for ethanol fuel vehicles how would you prepare some new catalysts to minimize or eliminate acetaldehyde production completely?

5. 
   

   (total=4 points) 化学代写

2% Pd/ϒ-Al₂O₃ supported on a monolith is to be used to abate the organic pollutants from a natural gas fired power plant. What characterization methods for each (a, b and c) would be used to determine the various modes of deactivation for each separate case listed below? Also suggest the shape of the conversion/temperature profile, you generate in the lab from a sample of deactivated catalyst using hexane as a model compound. In some cases. there may be more than one deactivation mode possible. Consider each separately.

1. (1 point) The data recorded over-night indicated the catalyst saw an excessively high temperature due to a failed heat exchanger upstream.
2. (1 point) It is known that some sulfur is present in low quality natural gas
3. (1 point) A heavy organic material in contaminated is depositing and masking the catalyst causing deactivation. Sketch the conversion vs temperature profile you would observe when performing a lab tes.t
4. (1 points) How might you remove the hydrocarbon from the catalyst (regeneration) and what characterization would be helpful?

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