Presented by - refpet.com 2017 CALGAVIN Presentation.pdf · Presented by : Martin Gough ......
Transcript of Presented by - refpet.com 2017 CALGAVIN Presentation.pdf · Presented by : Martin Gough ......
Topic
Values and benefits of improving the
performance of heat exchangers
Presented by :
Martin Gough, Managing Director,
CALGAVIN Ltd
>The answer must include…
Least risk
Cost effective
Proven technology
‘Every plant wants to save
energy but how can this be
achieved with existing plants?’
High energy savings = Unrealistic high
CAPEX
> Energy studies/Heat Transfer
models do not identify operational
issues such as
Fouling
Underperforming exchangers
Under-designed exchangers
Maldistribution
Available space
Mechanical problems (e.g.vibration)
Corrosion/Erosion
Control issues
> Tubeside heat transfer enhancement system
Direction of Flow
Empty tube- cooling viscous process fluid
>Flow stratification
Maldistribution problems
Effects of hiTRAN Thermal Systems
FOULING: Threshold Models
Reduced Wall Temperatures
Increased Shear Stress
Reduced Fouling
Lessons learned:
-0.2
0
0.2
0.4
0.6
0.8
1
-10 -5 0 5 10
> hiTRAN tube side velocity profile with increased shear
Velocity profile hiTRAN Re = 500
Radial position [mm]
hiTRAN measured
Re = 500
Turbulent theory
Re > 10000
Laminar theory
Re < 2300
U / Umax [-]
Velocity profile near to
the wall similar to
turbulent flow even
under laminar
conditions
Shear stress distribution with hiTRAN Thermal Systems
hiTRAN loop
Water
Reynolds [-] 30000
Density [kg/m3] 1000
Velocity [m/s] 2.06
f-factor [-] 0.012
Plain shear stress [Pa]
12.7
CALGAVIN Global Accomplishments Case Studies
Double Enhanced Helical baffle / hiTRAN Dalia FPSO
Client: Total Oil, Angola
Contractor: Saipem s.a.
Exchanger: Interchanger Top Deck of FPSO
Tubeside Fluid: Dry Crude (87.5 C to 70.1C)
Shellside Fluid: Wet Crude (50.5 C to 60.7 C)
Problem -
High Viscous dry crude limits heat transfer, Laminar flow conditions conducive to fouling, limited plot
space/weight available
Plant Improvement – CALGAVIN Solution/Benefit
• Reduced exchanger size/plot space from 9 shells to 2
• Four fold increase in overall heat transfer
• Uniform flow velocity and improved distribution - Reduced fouling
Size comparison - Conventional / HELITRAN
plain /
single.Segme
ntal.
hiTRAN® /
helical
baffle
gain
OHTC [W/m2K] 59.9 242.7 4x
Tube side:
HTC [W/m2K] 95 770 8x
dp [bar] 140 150
Flow velocity [m/sec] 0.92 0.45 ½
Reynolds [-] 1680 800 ½
Residence time [sec] 102 27 ¼
Shell side
HTC [W/m2K] 455 789 ~2
dp [bar] 1.50 1.25
Flow velocity [m/sec] 0.41 1.3 3
Reynolds 250 635
Wall temperatures [°C] 59.2 65.6
Geometry
Shell in series [-] 3 1
Shell in parallel [-] 3 2
Total no. of Shells [-] 9 2 ~4
Tube Flow path [m] 94.5 12.2 1/8
Tube length [m] 5.25 6.096
Total tube count [-] 16002 3640 ~¼
Tube passes [-] 6 2
Total HT area [m2] 6420 1704 ~¼
Plot space [m2] 104.5 26.2 ¼
Weight wet [kg] 401148 130716 1/3
Exchanger costs [%] 100 35 ~1/3
Conventional HELITRAN
Helical baffle on outside
hiTRAN tubeside
Feed/Effluent Exchanger Enhancement
Client: LUKOIL, Volgograd, Russia
Contractor: N/A
Exchanger: TEMA AES with Helical baffles
Tubeside Fluid: Reactor Effluent (308 C to 115C)
Shellside Fluid: Crude/Hydrogen gas mix (44.8C to 240C)
Problem –
High fuel consumption caused by limited performance, hindering plant
capacity increase.
Plant Improvement – CALGAVIN Solution/Benefit
• Reduced Maldistribution improved exchanger performance
• Recovered 4.6MW of energy on the fired heater at full flow
• Fuel Saving of US$233,000 per annum at original flow rate, enabling higher throughput
hiTRAN installation and benefits
before (empty) after (hiTRAN)
Tube pressure drop 25mbar (>85% nozzles) 200mbar (~10% nozzles)
Tube side heat transfer <285 W/m2K ~980W/m2K
Shell feed outlet temp 240C 314C
Tube effluent outlet 115 82
Mass flow 27kg/sec 42kg/sec
Load on fired heater 4.2MW 2MW
Annual energy savings of $ 233000
Crude Exchanger
Client: Pemex, Mexico
Contractor: EIGSA
Exchanger: Preheat train
Tubeside Fluid: De-salted Crude (59.5 C to 53.5C) Shellside Fluid: Wet Crude (33.6 C to 39.3C)
Problem -
New plant where heat exchanger costs were appearing excessive in design phase, hindering commission process.
Plant Improvement – CALGAVIN Solution/Benefit
• Reduction from original train design of 20 shells down to 8. • Saving significant plot space and capital cost. • Approximate saving in excess of US$2 million.
Original Design
2 shells in series, in 5 parallel rows
for each train.
hiTRAN Enhanced
4 shells in parallel for each train,
reduced size exchangers
Original Design compared to hiTRAN enhancement - 2 Trains
>Thank you for listening
Any Questions?