Analysis: The reactor effluent contains 1-butene, isobutane, n-butane, methanol, and MTBE. Given: Process flow diagram and for production of methyl tert-butyl ether (MTBE). An ESA separation is easier to design.Įxercise 1.5(b) Subject: Producing ethers from olefins and alcohols. The use of an MSA can make possible a separation that can not be carried out with an ESA. If the MSA is incompletely recovered, a small amount of contamination may result. Also, some MSA will be lost, necessitating the need for MSA makeup. Analysis: With an MSA, an additional separator is needed to recover the MSA. Find: State the advantages and disadvantages of ESA and MSA. Given: Differences between an ESA and an MSA. This minimum work is independent of the process.Įxercise 1.4 Subject : Use of an ESA or an MSA to make a separations. It can be shown that regardless of values of y between 0 and 1, that Wmin is always positive. From a chemical engineering thermodynamics textbook or Table 2.1, Eq. However, there is a change in entropy, determined as follows. Therefore, the change in enthalpy is zero. Analysis: As an example, consider the isothermal minimum (reversible) work of separation of an ideal binary gas mixture. Find: Explain why the separation of a mixture requires energy. Given: The first and second laws of thermodynamics. Energy is required to separate the different molecular species.Įxercise 1.3 Subject: Separation of a mixture requires a transfer of energy to it or the degradation of its energy. The separation of a mixture does not occur naturally or spontaneously. By the second law of thermodynamics, a natural process tends to randomness. It may take time, but concentrations of components in a single fluid phase will tend to become uniform, with an increase in entropy. Analysis: Mixing is a natural, spontaneous process. Find: Explanation for why mixing and separation are different. Bottoms from D3, containing residual CCl4, is recycled to reactor R1.Įxercise 1.2 Subject: Mixing is spontaneous, but separation is not. Bottoms from D2 is distilled in D3 to recover a distillate of CCl3F, which is dried with activated alumina in S2. The gas leaving A3 is distilled in D2 to obtain CCl2F2 as a distillate, which is then dried in S1 by adsorption with activated alumina. Moisture is removed from the gas leaving A2 by absorption with H2SO4 in A3. The gas from A1 contains residual HCl, which is neutralized, and chlorine, which is absorbed, by aqueous NaOH, in A2. The distillate enters absorber A1, where HCl is absorbed by water to produce a byproduct of aqueous HCl. The reactor effluent is distilled in D1 to remove the CCl4 as bottoms, which is recycled to R1. The normal boiling points in oC of these components in the order of decreasing volatility are: HCl Cl2 CCl2F2 CCl3F CCl4 H2O The effluent from the R1 is HCl, CCl3F, CCl2F2, unreacted CCl4, and small amounts of water and chlorine. The HF contains a small amount of water as an impurity. Find: Draw a process flow diagram and describe the process.ĭescription of Process: Two main reactions occur: CCl4 + HF CCl3F +HFĮxcess carbon tetrachloride is reacted in R1 with HF in the presence of antimony pentoxide catalyst and a small amount of chlorine to maintain catalyst activity. Given: Flow diagram and a brief description of a fluorocarbons production process in "Chemical Process Industries", 4th edition, by Shreve and Brink and also in "Shreve's Chemical Process Industries", 5th edition, by G. Exercise 1.1 (i) Known: Fluorocarbons can be produced from the reaction of carbon tetrachloride and hydrogen fluoride followed by a number of separation steps.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |