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1-5 In a plant with an annual production capacity of 1500 t of styrene via the dehydrogenation of ethylbenzene, the amount of steam added is 2.6 kg of steam per kg of styrene, and the conversion rate of ethylbenzene at an inlet temperature of 650°C is 44.4%. The styrene yield was 40%, with the remaining by-products being benzene at 3%, toluene at 5%, and coke at 2%. The device operates 300 days per year. The purity of the raw material ethylbenzene is 98% (by mass), with the remainder being toluene. Then the total amount of gas produced after the reaction is ( ). A. 8.62 kg B. 8.35 kg C. 8.53 kg D. 7.676 kg Answer: 1-5 CC. The answer is correct. Chemical reaction equations:
C6H5C2H5 → C6H5CH=CH2 + H2 106 104 2
C6H5C2H5 + H2 → C6H5CH3 + CH4 106 2 92 16
C6H5C2H5 → C6H6 + C2H4 106 78 28
C6H5C2H5 → 7C + 3H2 + CH4 106 7×12 3×2 16

(1) The production rate of styrene per hour is… The amount of ethylbenzene required per hour is: The amount of ethylbenzene converted per hour: 530×0.444 = 235.32 kg/h = 2.22 kmol/h. The amount of unreacted ethylbenzene: 530 – 235.3 = 294.7 kg/h. The amount of steam required per hour: 530×2.6 = 1378 kg/h. The amount of industrial raw material, ethylbenzene, required per hour is…; the amount of toluene required is 10.8 kg.

(2) Quantities of various components in the products: Styrene: 208.3 kg. Toluene: Benzene: 2.22×0.03×78 = 5.23 kg. Coke: 2.22×0.02×7×12 = 3.72 kg. Ethylbenzene: 294.7 kg. Ethylene (gas): 2.22×0.03×28 = 1.86 kg. Methane (gas): (2.22×0.05 + 2.22×0.02)×16 = 2.49 kg. Hydrogen (gas): (2 + 2.22×0.02×3 – 2.22×0.02)×2 = 4.177 kg. The total amount of gas is 1.86 + 2.49 + 4.177 = 8.53 kg.
A. The answer is incorrect. B. The answer is incorrect. C. The answer is incorrect. All 3 answers are due to incomplete calculation during the computation process; not all of the generated gas was taken into account. A. One option is missing: hydrogen reacting with ethylbenzene produces toluene and methane; therefore, the answer is 8.62 kg. B. The answer is 2.22×0.02, which is obtained from the reaction in which ethylbenzene decomposes into carbon, hydrogen, and methane. The total amount of hydrogen is (2 + 2.22×0.02 – 2.22×0.02)×2 = 4.0 kg, and the total mass of gases is 8.35 kg. D. There is an error in the calculation for methane gas