Evaporator Optimization Project

Bryan PicouJames Roberts

Advisor: Dr. Junkun MaET 493

Instructor : Dr. Cris Koutsougeras

Domino Sugar Refinery is in Arabi, La Produce 8 million pounds of sugar per

day on average It is the third largest sugar refinery in

the world

Domino Sugar

Evaporator Optimization Project

Steam is one of the most expensive resources for a refinery• Take the current operation of the

evaporators and make it more efficient• Take the current operation of the melters

and eliminate the steam

Evaporators Evaporator uses

steam in a vacuum to heat the sugar liquor and lower its density

Left over vapors from this process is what we are trying to optimize

Melter Takes the raw sugar and uses steam

to melt this sugar into a liquid. It uses direct steam injection Vapors from evaporator will be

rerouted to power the melter

Current Operation

Current Operation

Sugar Parameters Based upon 8 million pound melt rate 8 % scrap rate Sugar going into melters assuming

70 Brix

Sketch of New Operation

Energy required to Melt Sugar

Q = Cp of Sugar at 70 Bx* Mass of Sugar * ΔTemperature

Cp = 0.65 BTU/lb F Mass of Sugar at 70 Bx and 8 % scrap

rate = 478,800 lb/hr Ti = 130 F Tf = 170 F ΔT = 40 F Q = 12,448,800 BTU/hr

Energy in Steam With Phase Change

Q = Mass of Steam * Latent Heat of Steam

Latent Heat of Steam = 976.6 Mass of the Steam = 18,100 lb/hr Q = -17,676,460 BTU/hr

Barometric Condenser

Condenser Design Qsteam = Qsugar

Mass of Steam * Latent Heat of Steam = Cp of Sugar * Mass of Sugar * ΔTemperature

Rearranging: Mass Steam = (Cp of Sugar * Mass of

Sugar * Δtemperature)/Latent Heat of Steam

Condenser Design Mass of Steam = (0.65 * 478,800 *

40)/976.6 Mass of Steam = 12,747.08 lb/hr

Energy in Steam without Phase Change

Q = Cp of Steam * Mass of Steam * ΔTemperature

Cp = 0.45 BTU/lb F Mass of Steam = 5,353 lb/hr Ti = 188.5 F Tf = 170 F Q = -44,563.045 BTU/hr

Energy in Steam with Phase Change

Q = Mass of Steam * Latent Heat of Steam

Latent Heat of Steam = 976.6 Mass of the Steam = 12,747 lb/hr Q = -12,448,800 BTU/hr

Total Energy Going to Melters

Qsteam without phase change + Qsteam with phase change

Qtotal = -12,493,363 BTU/hr

Steam Pipeline Design Volumetric Flow Rate = Velocity *

Area Velocity = Volumetric Flow Rate/Area Volumetric Flow Rate of Steam =

18,100 * 47.344 = 856,926.4 ft3/hr Area of 16 in pipe = 1.396 ft2

Velocity = 856,929.4 ft3/hr / 1.369 ft2 = 170.56 ft/s

Condenser Design (Sugar) Mass of Sugar = (Mass of Steam

being condensed * Latent Heat of Steam) / Latent Heat of Sugar

Enthalpy of Sugar at 70 Bx and at 188.5 F = 82.47 BTU/lb

Mass of Sugar = 150,949.436 lb/hr

Sugar Pipeline Design Volumetric Flow Rate = Velocity *

Area Velocity = Volumetric Flow Rate/Area Volumetric Flow Rate of Sugar =

150,949.436 * (1/92.2) = 1637.196 ft3/hr

Area of 4 in pipe = 0.0872 ft2

Velocity = 5.214 ft/s

Pressure Loss in Steam Pipeline

Head Loss = friction factor * (Length/Diameter) * (Velocity2/ 2*gravity)

HL = 0.015 * (377.95 ft/ 1.33 ft)*((170.567 ft/s)2/ (2*32.2 ft/s2))

HL = 1920.83 ft

Pressure Loss in Steam Pipeline

Bernoulli’s Equation: P1 + Z1 + V1

2 - HL = P2 + Z2 + V22

Υ 2g Υ 2g

Rearranged P2 = [(P1/Υ)-HL * Υ] P2 = [(8 * 144) – (1920.83 * 0.0193)] P2 = 7.743 psi

Residence Time λ= Volume of Melter / Volumetric

Flow Rate Volume of Melter = 329.867 ft3

Volumetric Flow Rate = 2168.675 ft3/hr

λ= 9.13 min

Sugar Dissolution Lab

5 10 15 20 25 30 35 40 450

20

40

60

80

100

120

140

160

180

200

f(x) = 246.754029262766 x^-0.17322576787728R² = 0.939380810072085

Sugar Dissolution

Temp (°F)Power (Temp (°F))

Time (min)

Tem

pera

ture

(F)

Melter with 10 % increase in Volume

λ= Volume of Melter / Volumetric Flow Rate

Volume of Melter = 400.553 ft3

Volumetric Flow Rate = 2168.675 ft3/hr

λ= 11.082 min

Deliverables Sketch of future operation (Nov) Energy of vapors (Nov) Vapor Flow Rate (Nov) Energy Required to melt sugar (Nov) Residence time of melters (Dec) Design new melter (Dec)

• Designing the new melters based on energy requirements and availability

Design condenser (Dec)• Flow Rates, Pressure and Temperature Differences• Energy Transfer

Deliverables Design Vapor and liquor Pipeline

(Dec)• Determine pipe size • Stress Analysis• Material Selection• Minimize Energy Loss

Design Heat Exchangers (Feb)• Size of Heat Exchangers• Materials of Heat Exchangers• Energy Transfer

Deliverables Design Pipeline Support Structure (Feb)

• Deflection• Stress Analysis on Structure• Distance between supports• Material Selection

COMSOL (March)• Pipeline stress analysis• Structural Support Stress Analysis• Pipeline Deflection• Beam Deflection

Deliverables Design New System Layout (March)

• ACAD Sketch• Instruments Selection• Space Requirements

Control Sequence (April)• Safety• Ladder Logic (PLC)

Deliverables Cost Analysis (April)

• Yearly savings from cutting down steam consumption

Project Cost (April)• Cost of New Materials and Machines• Cost of a Contractor installing all Materials

and Machines

James Project Responsibilities

Sketch of Future Operation Energy Required to Melt Sugar Residence Time Design Melters Design Sugar Liquor Pipeline Design Structural Support System COMSOL Design New System Layout Control Sequence

Bryan’s Project Responsibilies

Sketch of Future Operation Energy of Vapors Vapor Flow Rate Design Condenser Design Vapor pipeline Design Heat Exchanger COMSOL Design New System Layout Cost Analysis, Project Cost Analysis

References Domino Sugar Corporation Cane Sugar Refining Handbook www.sugartech.co.za