Question

To avoid any accident a boil-off gas compressor with 0.2% volume full tank capacity per day discharge is installed in a plant. The detail design of the storage tank is as below: Tank Diameter 15 m Tank Height - 15 m Ceiling (Root) - black body at Tree Liquid CH4 surface - black body at TS Side wall - gray, diffuse (03-06) at T-TRT Max. Liquid depth Lmax-10 m Tror-55°C 2 a) For this assembly, find the net radiative transfer to the liquid in kW, for different values of Liquid height (5, 6, 7, ..., 10 m). b) Find if the capacity of boil-off gas compressor is sufficient to condense the flow rate of evaporated Methane? LV Thermophysical properties of Methane Critical Temperature, T-190.5 KP 4,6 MPa T-113.15 KPI atm. K Co k/kg, pkg/m) Ns/m?) KW/m.K] Pr (Prandt number) Liquid at latm, Tsat. 3 349 422.63 1.17 x 10 0.1862 I 2.098 a lflatent heat of vaporization) 511 Gas at latm, Tat. 2260 1.75 4.20 X 10* 0.0132 0.789 h

Answer 1

solution: Given Tsat = -160°C. Palatm - Tez 190.5t, Pe 24.6 MPa Assuming no shield the heat transfer - Qw' = FR GA (T,"_T24) (Assuming Black Body] where Fia= shape factor= 1 (parallel plates) ? a=Stefon Bottaman constant C = 5-678108 w/mak A = TDR For (lomantmin) 4 353.15+113.15 -233.15K = 30 mcharge. Dis not given so we take b=lm A = 0.78 m2 T = Trouft Tliquid a T2 = 113.150 Qwo = 5:07 x 10-6X0.78 $(233.254-1118.754) - Qw" = 123.434 sis . 6 with shield : We known that ( ) with Shield het without Shield na noid stield Here no! Hence the ) win Shield sh to, without shield Wilt without It Scanned with la ca without shield = 123 434 5ls

2 30 (Qw) without shield - 127434 €61.7175/5 from Imax to Imin there will be (lmax-Imin) : 30m additional gap .Qw: 60-707 2.0875/s] ne capacity TIDO tH let H= im D=1m Vol.of tank = 0.78m? Now mass of 0.001som? gas=o0olsox Density 50.659 kg . : Heat required = mcp (TR-7) -0.659x3.349 x (80-1-160)) 5529.9215 BOG requirem ents are generally 1000 msin Here the volume rate is will know the requirement Hence we can screw compressor oths lower C.R. Note: Hi students it you have any doubte On the solution please leave a comment, and don't dislike the solution Scanned with CamScanner