Text: PLEASE ANSWER QUESTION 7
CE212: Fundamental Principles of Chemical Engineering Short Answer Question (10 words per answer; 30 points):
1) Name three methods by which you could obtain heat of reaction values.
2) Hess's law is a by-product of what property of enthalpy?
3) What term is used to describe a positive ΔH value? Is heat released or absorbed in this case?
4) Provide a quantitative comparison that proves incomplete combustion releases less energy than full combustion.
5) Besides establishing the overall energy balance equation, what is the key prerequisite step for beginning either of the two Chapter 9 energy balance methods?
6) List common, convenient reference state conditions for 1) air and 2) steam. In the case of air, list two reference state conditions and explain how you would perform enthalpy calculations for each.
Diagram Problem (15 points):
7) For the following problem, 1) diagram the waste heat boiler and separation units (with the separation units combined as a single unit) and 2) indicate potential uses of exiting streams from these units. Formaldehyde is produced by decomposing methanol over a silver catalyst: CH3OH -> HCHO + H2. To provide heat for this endothermic reaction, some oxygen is included in the feed to the reactor, leading to the partial combustion of the hydrogen produced in the methanol decomposition. The feed to an adiabatic formaldehyde production reactor is obtained by bubbling a stream of air at 1 atm through liquid methanol. To avoid deactivating the catalyst, the maximum temperature attained in the reactor must be limited to 600°C. For this purpose, saturated steam at 145°C is metered into the air-methanol stream, and the combined stream enters the reactor. A fractional methanol conversion of 70.0% is achieved in the reactor, and the product gas contains 5.00 mole% hydrogen. The product gas is cooled to 145°C in a waste heat boiler in which saturated steam at 3.1 bar is generated from liquid water at 30°C. Several absorption containing 37.0 wt% HCHO.
