USC Chemical Engineering Student Process Equipment Design 2017 D e p a r t m e n t o f Chemical Engineering
FORM 1-4-Calculation Sheets
Transesterification Reactor Sizing
Talamban, Cebu City, Philippines 6000
DESIGNER(S):
CHUA, MARY ANTOINETTE G. GOLLEM, BABE EDEN JOY O. MALINAO, HUGH LAMBERT L. MERCADO, ARMEL JAY P.
Equipment Tag: Equipment Description: Calculation Sheet No:
R-01 Heterogeneous Base-catalyzed Base-catalyzed Transesterification Reactor XXXX-XXXX
DESIGN MANUALS OR TECHNICAL REFERENCES [1] Octave Levenspiel, Chemical .
Reaction
Engineering ,
Ind.
Eng.
Chem.
Res, Res ,
1999,
XXXVIII
[2] H. S. Fogler, ‘Catalyst Decay’, Elements of Chemical Reaction Engineering , 894.1968 (2006), 881 –94. –94. [3] Abdul [3] Abdul Rahim Yacob and others, ‘Catalytic Performance by Kinetics Kinetics Evaluation of Novel KOHModified KOHModified Zinc Oxide in the Heterogeneous Transesterification of Rice Bran Oil to Biodiesel’, Biodiesel’, International Proceedings of Chemical, Biological and Environmental Engineering, 84.17 Engineering, 84.17 (2015), 101 –7 –7 . . [4] S. Afandizadeh and E. A. Foumeny, ‘Design of Packed Packed Bed Reactors: Guides to Catalyst Shape, Size, and Loading Selection’, Applied Selection’, Applied Thermal Engineering Engineering , 21.6 (2001), 669 –82 –82 . 1359-4311(00)00072-7>. DESCRIPTION The transesterification process taking place inside the heterogenous base-catalyzed transesterification reactor, which in this case is a packed-bed reactor, is for further production of fatty acid methyl esters (FAME) from the remaining triglycerides (TG) of the output stream of the preceding pre ceding step, which is the heterogeneous acid-catalyzed esterification of partially refined rice bran oil, in order to meet the the FAME demand. ASSUMPTION(S)/BASIS 1. Fluid is incompressible; thus, density changes are negligible. 2. Methanol supplied is in excess, thus, the reaction is pseudo-first order. 3. Catalyst decay follows zeroth order decay rate law. 4. The volume of the packed bed is equal e qual to the volume of the reactor. 5. The catalyst catalyst particles are spherical having ε = 0.4
[1] [3] [2] [4]
NOMENCLATURE(S) Symbol or Notation
, , ∗ ,
Description Reaction rate for triglyceride Weight of catalyst inside the bed Number of moles triglyceride Initial number of moles triglyceride Time Conversion of triglyceride Entering molar flowrate of triglyceride Reaction rate constant Activity of the catalyst at time t Activity of the catalyst at t = 0 Catalyst decay rate constant Lifespan of the catalyst Lumped constants Number of moles catalyst per mole reactant Turnover number Turnover frequency Initial triglyceride concentration Bulk density of the catalyst Porosity of the bed Volume of the reactor
INFORMATION FLOW DIAGRAM
= 100 = = () () = + () ,, = ′(),(1 )
′
1 −
, න, , ,, = , න, , ,
, = (1) 4 = ൬ ൰ = 1
SYSTEM SKETCH
Feed Stream Triglyceride TG 4, 068.41 (kg/h) Free Fatty Acid 30.93 FFA (kg/h) Water (kg/h) 47.83 Methanol (kg/h) 7, 136.62 Glycerol (kg/h) 656.84 FAME (kg/h) 7, 059.17 Temperature (K) 333.15 Pressure (MPa) XXX Methanol Stream Methanol (kg/h) 1,180.32 Temperature (K) 333.15 Pressure (MPa) X,XXX.xx
Outlet Stream Triglyceride TG 81.37 (kg/h) Free Fatty Acid 30.93 FFA (kg/h) Water (kg/h) 47.83 Methanol (kg/h) 7, 876.44 Glycerol (kg/h) 1, 078.89 11, FAME (kg/h) 093.75 Temperature (K) 333.15 Pressure (MPa) XXX
CALCULATIONS To calculate for the TON, first, Calculating TON, where
is determined from the mass balances:
is equal to 0.0555 mol KOH-ZnO per mol reactant: = 100 = 0.100 = 1802.019 0 555
The lifetime of the catalyst, td, is then calculated, where the TOF value is obtained from literature, and is equ al to 11.5 hr -1.
With a0 = 1, and a(td) = 0,
= 1802.019− = 156.7 ℎ ≈ 6.53 = 11.5 ℎ = 01 = 0.154 − = () 6.53 () = + () = 10.154 = 0.0003(10.154),(1)
a(td) is then determined using the equation which yields
From the rate law, substituting values will yield
The weight of the catalyst is obtained using
. . = , න = න ∗(1)
XTG is plotted against 1/-r’TG to determine the value for the integral term. 45000000 ) 40000000 l o m35000000 / t s y 30000000 l a t a 25000000 c g 20000000 s ( 15000000 G T ' r 10000000 / 1 - 5000000 0 0
0.2
0.4
0.6
0.8
1
XTG The determined area under the curve has a value of 45808.22, which is also equal to W .
+ 0.45 ∗5.61 0 . 0 47 ∗2. 1 2 ∗ + ∗ = + = = 5. 2 83 0.047 +0.45 = 45808.22 = 14451.42 ≈ . = (1) 5.283(10.4)
Calculation of bulk density of the catalyst:
Calculation for the volume of the reactor (assuming ε=0.4):
Solving for the diameter of the reactor,
= ൬4൰ = 4(14.45 ) = .
Assuming an L/D ratio of 1:
= = .
RESULTS AND CONCLUSION From all the calculations for the sizing of the packed-bed reactor for the transesterification of pretreated rice bran oil, the calculated volume of the reactor that would accommodate either a 20%-FFA RBO or a 7%-FFA RBO is 14.45 m 3 with a diameter of 2.64 m and a bed height of 2.64 m, as well. COMPUTER PROGRAMS USED (Version No.)
Microsoft Excel 2016/Microsoft Visio 2016
ELECTRONIC CALCULATION FILE NAME:
REV
DATE
A
05/31/2017
REVISION DESCRIPTION
CHE 514N Reactor Sizing-10232017.xlsx
BY
CHKD BY
APPVD BY
