tube inserts for heat exchangers
TRANSCRIPT
P
TUBE INSERTS for TUBULAR HEAT EXCHANGERS
- Turbotal® - Fixotal® - Spirelf®
1. Heat exchangers
Our Solution’s Purpose: Maintaining your tubular heat exchanger at its highest level of efficiency Difficulties encountered • Progressive fouling of exchanger tubes. • Effects observed on the heat exchanger:
- Reduction in flow rate (or bypass) Increase in DP - Time in service reduced
- General reduction in productivity - Increase in fuel consumption (in the crude preheat train
when installed before a furnace) The fight against fouling of tubes The usual solution is to clean heat exchangers at
regular intervals. - The costs of maintenance and the associated
reduction in production are substantial.
- Other solutions are possible, such as the addition of
anti-fouling additives. They can be inadequate,
because of the deposition of asphaltenes
constituents on the tube walls.
- As the ultimate solution, a revamp of the unit might
be sometimes necessary.
Insert technology • Inserts are devices installed in heat exchangers.
• They continuously reduce fouling and improve
heat transfer by means of mechanical effects. • Today they are widely used in preheat trains in oil
refineries.
Inserts:
Reliable technology, proven results PETROVAL tube insert technologies 3 types of inserts resulting from TOTAL R&D are now available: Turbotal
®, Fixotal
® and Spirelf
®.
On the basis of more than 15 years of experience,
PETROVAL tailor made the inserts according to the
operating conditions for each of your exchangers.
Expected results • For heat exchangers
- Reduction in fouling (up to 80%)
- Improvement in heat exchange (up to 100%)
- Increased time in service (> 2 times)
- Higher outlet temperature (3-10°C) • For production unit
- Energy savings at the furnace
- Furnace debottlenecking and increase in production
capacities
- Savings in maintenance, reduction in production losses
2.The inserts
Reduction in fouling:
Turbotal® and Spirelf
®
Principles of operation • These two systems are continuous online
cleaning devices, whose purpose is to
mechanically reduce the fouling layer on the tube
walls (rotation or/and vibration) • Additionally, they provide microvibrations leading to
more turbulences and consequently more heat
transfer Main applications
Preheat train for crude oil
Water treatment feed exchanger
Reboilers Heat exchangers limiting the operation of the unit
Improvement in heat transfer:
Fixotal®
Principles of operation • Fixotal
® is fixed to the internal wall of the tube and
acts as a source of turbulence, preventing the
stagnation of product inside the tube. • The purpose of this fixed device is mainly to
increase the rate of heat transfer. • It also reduces some types of fouling linked to wall
temperature (polymerization, solidification of paraffin,
scaling, etc.)
Principal applications Air coolers Water cooler U tubes 2 phase flow
Turbotal®: reduction in fouling Flow
Flow
Fouling in tubes Rotation Microvibration
about the axis
1 month 6 months Spirelf ® : reduction in fouling
Flow Flow
Equipped with inserts
Radial Axial
1 month 6 months
vibration vibration
Fixotal®: improvement in heat transfer
Standard
Flow Flow
Increase in turbulence effect
Turbotal®, Fixotal® and Spirelf®
They are multi-purpose: we adapt them to the properties of fluids (temperature, viscosity, flow velocity, etc.). They are quick and easy to install.
Heat Exchangers do not to require modification.
Your conditions of production and fluid properties will determine the choice between the 3 devices.
3. Performance in industry
Reduction in rate of fouling
Spirelf®
Reduction in the rate of fouling due to coking in a crude preheat exchanger Spirelf®. Results published by ExxonMobil, (United States). Hydrocarbon Processing. 1999.
Fouling factor, hr-ft
2-F/Btu
0,028
0,024 F.F. without Spirelf®
0,020
0,016
0,012 F.F. with Spirelf®
0,008
0,004
0,000 Duration in days
0 200 400 600 800 1.000 1.200 1.400 1.600 1.800
After eight months in use: • The crude preheat exchangers were completely fouled • Their thermal performance was reduced as a result.
• This phenomenon recurred from one run to another.
The use of Spirelf
® allowed the reduction of level of
fouling to be kept to a minimal value. • Significant improvement of thermal performance • Increase the length of service without maintenance
shutdown (more than 3 years). Turbotal® Reduction in the fouling rate in CDU heat exchangers Turbotal®, crude / gas oil pumparound
M2 . °C.h/kcal X 10 000
90 E 109 B without
80
with Turbotal®
70
60
50
40
30 E 109 A equipped
20
with Turbotal®
Duration in days
0
0 20 40 60 80 100 120 140 160 180 188 200 220 240 260 280 300 320 340
In order to verify the effectiveness of Turbotal® in iden-
tical operating conditions, a single branch of the preheat
train of an atmospheric distillation plant was equipped
with inserts. There was an immediate optimization of the
operating conditions of the equipped heat exchangers.
Performance • For heat exchangers
- Better operating conditions - Increased run time
• For the installation - Energy savings
- Maintenance savings - Reduced maintenance shutdowns - with
TURBOTAL®, it is possible to at least DOUBLE
the process operation time!
Advantages in a chemical plant
Spirelf® on a thermosiphon reboiler,
Chemical plant (Japan).
Reboiler general principle
U value Cleaning by water injection
500 2003 (without Spirelf®) Annular flux
450
2004 (with Spirelf®)
400
350
300 Separation
250 flux
200 Flux disrupted
150
by air bubbles
100
50 Duration in days Single liquid
0
phase
0 20 40 60 80
Without Spirelf® • Monthly cleaning by water injection to make the
distiller thermosiphon operate normally.
• Overall reboiler performance inadequate because
of progressive fouling.
With Spirelf® • Fouling and heat transfer under control. • Doubling of the thermal efficiency of the system. • Operating time without cleaning extended from one
month to one year.
Increase in operating time Study of fouling factors - T29 and T30 exchangers Turbotal®, crude. Atmospheric distillation tail.
Turbotal®
M2 . °C.h/kcal X 1000 removal ,
70 cleaning,
run without
60 18 months run with Turbotal®
insert
50
40 T30
30
20
10 T29 Duration in days
0
0 40 80 120 160 200 240 280 320 360 400 440 480 520 560 600 640
Case study using Turbotal
® -Turbotal
® removed after 18 months use.
-Turbotal® not reinstalled for 6 months, until next
shutdown.
-Considerable increase in fouling factor observed. -Turbotal
® reinstalled and fouling factor
significantly reduced, for another 18 months
• Subsequent use of Spirelf
® Heat exchangers equipped with Spirelf
®.
Thermal efficiency comparable with Turbotal®.
Spirelf
® have been reinstalled combined with chemical
cleaning carried out at regular intervals. Spirelf® was
maintained in service for 4 years in good operating
conditions.
4. PETROVAL offers:
Example: Energy Savings,
application in crude oil preheat train Refinery • 5.6 million tons / year • 120,000 b/d capacity • Plant: 6 exchangers before the furnace • Frequency of cleaning before using inserts: once
every 6 months
Performance • 1.5 years in use before cleaning • Average increase in CIT in the furnace: 6.8°C
Energy savings • Increase of 1°C in the furnace = 1.2 tons of fuel
saved per day
• Energy savings in 1.5 years: 4,450 tons of fuel = 445,000 €
Economic evaluation • Total savings: 445,000 €
• Payback time (ROI) = less than 6 months !!!
Other savings • Savings in maintenance • Savings in lost production avoidance
Overhead product
Distillation column
Atm. resid. Kero P/A
LPG Kero Gas-oil atm. Naphta
Light naphta
Better use of Heater Kero
Crude tank distillation tower
Diesel
Better cooling Desalter Fuel
of overhead product
Better cooling of atm. A longer cycle duration Energy Atm. residue
resid. before to be sent maintenance cost saving savings
to storage tank
PETROVAL can provide a free technical and economic evaluation
Based on the heat exchanger specification document and the actual working conditions • Technical study: feasibility, selection of insert and its design, anticipated improvements and general advice • Economic evaluation based solely on energy savings
PETROVAL offers • Manufacture of inserts (made in France) • Supervision of installation • Optional management of installation • Monitoring refineries and performance evaluation
PETROVAL France contact: tel +33 (0)2 35 31 00 00 - email: [email protected]
Canada contact: tel +1 514 377 3723 - email: [email protected]
USA contact: tel +1 713 527 9575 - email: [email protected]
Singapore contact: tel +65 9649 8740 - email: [email protected]