Name: Nguyen Huu Cong
ID: Cttt 10210113
ECH158B: Processes Design
Homework Assignment #1

Problem 2:
Flue gases are used for heating and pass through the tubes. The flue gases will contain traces of sulfur dioxide, so the tubes must be resistant with reactant and product in the system as: SO2, MEK, H2, 2-butanol as well suffer under high temperature and pressure.
Based on the conditions have indicated above we have to choose the appropriate material to satisfied. Firstly, we considered the non-metals. Non-metals do not change heat as well, so they are not to appropriate to be used as the material for tubes we selected.
Secondly, we considered metals here. Likewise iron and aluminum, copper, but they are not resistant to corrosion as well to SO2 and another reason is metals do not suffer under high pressure and temperature.
Another choice is Stainless Steel, The stainless steelsare the most frequently used corrosion-resistant materials. Also, they have good behavior under high temperature and pressure.
Look up some characteristics of some alloys resistant to corrosion in Chap 10- PTW. We figured out some alloys can deserve our condition above are aluminum, copper and its alloys.
Aluminum, Copper and its alloys resist acid attacks by a passive aluminum oxide layer, so they can also be chosen. Considering hydrogen embrittlement, alloyed steels are better to be used. However the price of aluminum and its alloys is relatively high.
So, for some characteristics of materials we discuss above. Materials making for tubes should be resistant to corrosion. Then, the carbon steel with alloys, the stainless steels, aluminum and its alloys and copper and its alloys are the good choice. But we need to consider the prices of these to set up and replace. Alloys have to high prices for each, Stainless Steel may be popular and appropriates for material of the tubes.
To choose the materials for the shell, the shell should be resistant to methyl ethyl ketone, 2-butanol and hydrogen, working well under high temperature and high pressure. Also the heat conductivity needs to be limited to save energy (insulation).
Organic nonmetals cannot be used under such a high temperature.
The iron and carbon steels with alloying can be used but the better choices would be stainless steels.
Copper alloys and alloyed steels can be used as the materials for the shells. Considering the high price for alloys, the stainless steels may be the appropriated choice in this case.
Problem 3:
We have diameter D= 5.501in/12(ft/in)= 0.458 ft and
Cross-section area is Ac = π(0.5 ft)2/4 = 0.165 ft2, 𝜌 of water at 60oC is 62.4 lb/ft3.
And viscosity 𝜇 = 1.129 cP
So Reynold number is: Re =
𝜌𝑉𝐷
𝜇=
62.4𝑥12𝑥0.458
1.129𝑥6.72𝑥
10−4= 4.52x105

𝜀
𝐷= 0.00015/0.5 = 0.00033
Then, For Re > 105 we have fanning friction factor, f, is 0.0041 (Colebrook eqn. for turbulent flow)
For ∆L = 4500 (ft) so hf|straight=
12
2
2𝑥32.174)0.0041x
4𝑥4500
0.458)= 361 (ft-lbf/lb)
Static lift = 3000 ft. Neglect velocity head.
Total work: hw= 3000 + 361(ft-lbf/lb)= 3361 (ft-lbf/lb)
Q = A.V= 0.165ft2 x 12 ft/s = 1.98 ft3/s
P= 33361x1.98x(62.4/550) = 733 HP(theoritical)
Total cost: 755 (hp)x 0.746(kW/hp)x0.04/0.7($/kWh)= 32.18$/h
Problem 4:
Internal diameter of 1” Sch 40 steel piping is D = 1.02 in = 0.026m= 0.085 ft
V1 = 114.83ft/s, T1= 248oF= 460+248 oR = 708oR, P1= 6atm(abs)= 6x14.7 psia= 88.2psia

Using


To estimate the Lmax. Where Ma1 = V1/Vs , Vsis the sonic velocity in the medium pipe.
Assume adiabatic flow. For chlorine, γ=1.36 and MW=70.91.
Vs =
𝑔
𝑐
𝛾𝑅𝑇
𝑀𝑊 =
32.2
𝑓𝑡
𝑠
2(1.36)(10.73
𝑓𝑡
3.𝑙𝑏
𝑜
𝑅
𝑖𝑛
2.𝑙𝑏−𝑚𝑜𝑙)(144
𝑖𝑛
2
𝑓𝑡
2)708 oR
70.91(𝑔/𝑚𝑜𝑙= 822 (ft/s)
Ma1 = 114.83/822 = 0.1397,