1. Boilers are used in most chemical plants to generate steam for various purposes, such as to preheat process streams fed to reactors and separation units. In one such process, steam and a cold process fluid are fed to a heat exchanger where enough energy is transferred from the steam to cause a large fraction of it to condense. The uncondensed steam is vented to the atmosphere, and the liquid condensate is recycled to a deaerator into which another liquid stream (makeup water) is fed. The makeup water contains some dissolved impurities and other chemicals that help prevent deposition of solids on boiler walls and heating elements, which would lead to a reduction in operating efficiency and eventually to safety hazards, possibly including explosions. The liquid leaving the deaerator is the feed to the boiler. In the boiler, most of the water in the feed evaporates to form steam, and some of the impurities in the feedwater precipitate to form solid particles suspended in the liquid (kept in suspension by the chemical additives in the makeup water). The liquid and suspended solids are drawn off as boiler blowdown, either in manual bursts or with a continuous blowdown system. A diagram of the system is shown below. The symbol I is used for combined impurities and chemical additives. The makeup water contains 1.0 kg 1/2.0 × 103 kg H2O, and the ratio in the blowdown is 1.0 kg I/3.5 x 102 kg H2O. Of the steam fed to the heat exchanger, 76% is condensed. Blowdown Lost steam I kg I(aq+s)/3.5x10 kg H,0 H,O(v) Heat Process Boiler feedwater I(aq), H,O() fluid, T Steam H,O(v) НЕАТ DEAERATOR BOILER EXCHANGER Makeup water 1.0 kg I/ 2.0x10 kg H,O((1) T2 Condensate, H,0(1) 76% of steam entering exchanger (a) In your own words, describe why makeup water, chemical additives to the makeup water, and blowdown are necessary in this process Speculate on the probable Condensate, H,0(1) 76% of steam entering exchanger (a) In your own words, describe why makeup water, chemical additives to the makeup water, and blowdown are necessary in this process. Speculate on the probable disadvantage of making the I/H2O ratio in the blowdown (i) too small, and (ii) too large. (b) Assume a basis of calculation and draw and fully label a flowchart of the process. (When you draw the heat exchanger you can omit the process fluid, which plays no role in the problem.) mixing point, the reactor, and the separation process. Base the analyses for reactive systems on atomic balances. (b) Write and solve overall balances, and then scale the process to calculate the flow rate (SCM/h) of fresh feed required to produce 1000 kg CNT/h and the mass flow rate of CO2 that would be produced. (c) In your degree-of-freedom analysis of the reactor, you might have counted separate balances for C (atomic carbon) and O (atomic oxygen). In fact, those two balances are not independent, so one but not both of them should be counted. Revise your analysis if necessary, and then calculate the ratio (kmol CO recycled/kmol CO in fresh feed). (d) Prove that the atomic carbon and oxygen balances on the reactor are not independent equations.