Exploiting the Use of Compact Heat Exchangers Exchangers on Preheating Trains (AIC (AIChE hE 2008 2008 Spr Sprin ing g Meeti Meeting ng – 165d) 165d)
PETROBRAS R&D Center – CENPES Antonio V. S. de Castro*, M.Sc. Alan Alan T. Vila Vilas s Boa Boas s Claudio L. M. Kuboski Diom iomedes C. da da Sil Silva, M.S M.Sc c. Roberto A. Oliveira, M.Sc. Washington de O. Geraldelli, Ph.D.
Introduction
Higher prices of energy and oil Crude oil distillation unit is one of the highest energy consumers in a refinery. Opportunities Opportunities for heat integration: – In revamps revamps to process advantageous advantageous crud crude es – Spe Specia cial Met Meta allur llurg gy – higher heat recovery recovery
Threats: – Special Metallurgy due to naphtenic acids - higher higher inve investmen stments ts at at preheati preheating ng train train – increase on plot area area due to increase increase on heat recove recovery ry - might be a cons constrain traintt
Introduction
Compact Wel Welded Plate Heat Exchanger: – Special Metallurgy (Titanium, SMO, etc.) etc.) leads to attractive costs compared to a S&T – Compact (less plot area) – Lower temperature approaches than S&T – Innovative solution solution – Refinery designers designers don't have have enough information regarding the the performance: • Fouling • Mech Mechan anic ical al resi resist stan ance ce • Operat Operation ional al cautio cautions, ns, such such as as start start-up -up and shut-down
PETROBRAS Experience End of 2001, PETROBRAS Engineers visited a Refinery, in Europe, where a Compab Compabloc loc CP75 CP75 was install installed ed – Overhead Condenser with Crude C rude – Special Metallurgy required due to Chloride – 4 years without maintenance
August, 2002. Service with two heavy fluids – 13 exchangers at refinery refi nery since 1994 – Maintenance during winter shut-down s hut-down – Focus on Process Issues
Visit to refinery with two parallel units (one (one standstand-by) by) – Sep,2005 Sep,2005 Ref.: ALFA LAVAL
– HVGO vs. Crude Oil (high temperature) – Problems during the start-up (blocked pipe) – Operating since November,2004
PETROBRAS Experience June,2002 June,2002 – ALFA LAVAL LAVAL traine trained d PETROBRA PETROBRAS S Engineers Engineers how how to design design Compabloc Compabloc using using CAS200 CAS200 (ALFA LAVAL software) September September,200 ,2006 6 – Two-phase Two-phase fluid ALFA ALFA LAVAL LAVAL course, concerning crude oil vaporization – Lack of data data for temperatu temperature re x shear stress x fouling fouling rate
May,2006 May,2006 – Visit Visit to ALFA LAVAL LAVAL factory factory in France: France: - Main Mainte tena nanc nce/ e/In Insp spec ecti tion on//Clea Cleani ning ng Requ Requir irem emen ents ts - Manufacturing Pro Process
PETROBRAS Cases
CASE 1 P-68324A/B Ovhd Ovhd Gas Heater
P-68323A/B Ovhd Ovhd Condens Condenser er
P-68322A/B Feed pre-heate pre-heaterr
P-68325A/B Reboiler
Sour Water Stripping Unit: – Feed preheater – Overhead Condenser – Ovhd Gas Heater – Reboiler
Plot area constraints Fouling at Feed pre-heater Leakage at Ovhd Gas Heater
PETROBRAS Cases Fouling at Feed preheater preheater
Inadequate H2S Stripping Tower Operat Operation ion – corros corrosion ion
Leakage Leakage at Ovhd Ovhd Gas Heater Heater
Material replacement: From From Titan itaniu ium m to SM SMO
Actual Flow Rate (90m3 /h) ‹‹ Design (160m3 /h) Actual Actual Shea Shearr Stres Stress s (22P (22Pa) a) ‹‹ Design Design (60Pa) (60Pa)
Mitigation: Increase passes number (↑ Shear Stress) Control Review (by-pass) Self-cleaning Strainers
CASE 1, cont.
PETROBRAS Cases
CASE 2 Basi Basic c Engi Engine nee ering ring Desi Desig gn - Crud Crude e Dist Distililla lati tion on Unit Unit Revamp: – Increase Feed Rate – Heat Integration – Plot Area Constraints
3 Services: MVGO (2) and VR 220,000 bbl/d Start-up: 2011
PETROBRAS Cases
CASE 3 Conceptual Design (Revamp) 140,000 bbl/d
- Metallurgical Adaptation (TAN=2.1) - Operational Debottlenecking - Heat Integration Stu Study – Pin Pinch Analysis - Plot Area and Shutdown time constraints - Full Compabloc new preheat train suggested.
Compabloc Test at Refinery During conceptual design, neces necessity sity of a perfor performan mance ce test. A Compabl Compabloc oc CP30 unit unit has has been installed, in order to evaluate the performance of this equipment under unit conditions Vacuum Residue preheating Crude before the Desalter Low Crude Temperature: ~100 to 115ºC Operational and Maintenance experience
Compabloc Test at Refinery
Vacuum Residue
172
Crude Oil 103
E-106D 113
160
E-150
Compabloc Test at Refinery Step
Flow rate
Period
Objective
6 months
Thermal performance
Procedure
(design basis) 1
100%
a) Check pressure drop; b) Compare design X operational op erational data using CAS200.
2
50%
2 months
Fouling
a) Check pressure drop b) if fouling, go to phase 1; if not, go to phase 4.
3
4
100%
25%
2 months
2 months
Thermal performance and fouling Fouling
a) Check pressure drop; b) Auto cleaning capabity. a) Check pressure drop; b) Equipment shut-down for 10 days and restart it.
5
Cleaning
a) Open the equipment to check deposits; b) Cleaning with hidroblasting.
6
100%
3 months
Similar to phase 1.
Compabloc Test at Refinery
1st 1st Phas Phase e Resu Result lts: s: – Crude side measured measured pressure pressure drop was from 29 to to 47 47% of calculated values by CAS200; – VR side measured measured pressure pressure drop was from 123 a 167% of of calcul culated values by CAS200; – Difference Difference in global global heat transfer transfer coefficients coefficients (HT (HTC) was was much low lower. er. Me Measu asured valu alues were from de 88 88 a 11 111% of of calcul culated values by CAS200; – Problems Problems with Instrumentation Instrumentation could be the cause of of such difference in pr pressure drop
Compabloc Test at Refinery Compabloc loc Opening ing after 1st step (8 mon months) Defle eflect cted ed Baffl affle e (mech mechan anic ical al re resi sist stan ance ce)) – it was not not des designe igned d for for that that pur purpose pose
Crude Inlet
Vacu Vacuu um Resi sidu due e Inlet nlet
Compabloc Test at Refinery Pressure drop results - phases 2, 3 and 4 2.00 1.80 1.60 1.40
² m c / f g 1.20 k , p o r 1.00 d e r u s 0.80 s e r p
0.60 0.40 0.20
50% flow rate
25% flow rate
100% flow rate
0.00 1- Sep
2-O ct
2- Nov
CRUDE VACUUM RESIDUE
3- Dec
3- Jan
3- Feb
6-Mar
6-Apr
7-M ay
Period from 2006 up to 2007
7-Jun
8-Jul
8-Aug
8-Sep
9- Oct
Compabloc Test at Refinery
Flow Rate Vac acuu uum m Re Resi sid due vs Crude Ad-Hoc Trend 3000
2500
2000
1500
1000
500
1210-FI-299 160.63 M3/D 1210-FI-298 28.689 M3/D
Compabloc Test at Refinery Positive Aspects:
Nega Negati tiv ve Aspe Aspect cts: s:
- Equipmen ment ke kept itits th thermal mal performance; - Design, Ope Operatio tional and Maintenance Maintenance experience
- Mechanical cal Resistance (Leakage and Baffle); - Aspects not related to exchanger exchanger (instrumentation, (instrumentation, flow fluctuation, …)
- No fouling observed
Compabloc Test at Refinery Pressure
Crude Side Period od:: Jul/1 Jul/16/0 6/07 7 up up to – Peri Sep/20/07 Zero Flo Flow w Ra Rate te for for – Zero abo about 3 week weeks s.
Flow Rate
– No abnormal pressure variation.
Compabloc Test at Refinery Pressure
Vacuum Residue Side Period:: 16/Ju 16/Jul/0 l/07 7 up to – Period 20/Sep/07 Zero Flo Flow Rate Rate for 10 day days. s. – Zero Sign gnif ifiica cati tiv ve pres pressu surre and and – Si flow flow rate rate variati ariation on..
Flow Rate
Pressure Sep/01 to 17
Compabloc Test at Refinery
Inle Inlett Press ressur ure e VR vs Crude (Acc (Accor orde deo on Effe Effect ct))
Compabloc Test at Refinery Problem
Root Cause
Consequense
Leakage
Joint Failure
Vacuum Residue Leakage
Baffle Deflection
Overpressure or fatigue
Thermal performance loss
ALFA LAVAL: – Development Development of new gasket; gasket; – Adoption of reinforced reinforced baffles (for high high viscous fluids);
PETROBRAS: – Avoid surge surge pressure pressure (hydraulic (hydraulic hammer): hammer): • Star Startu tup p and and shut shutdow down n proce procedu dure res; s; • Slow low valv alve acti actio on;
– Drain the the equipment, equipment, in case of several several days days of shutdown. shutdown. – Panels bolting bolting hot retightening retightening after startup – Deposits prevention: prevention: • Strainers;
PETROBRAS Cases
CASE 3
Basic Engineering Design (Oct/07) Preheat Train before Desalter – Carbon Steel – Equivalent Cost
Preheat Train between Desalt Des alter er and PreFl PreFlas ash h Tower – Crude Vaporization – Special Metallurgy – Parallel Arrangement
PETROBRAS Cases
CASE 3
Basic Engineering Design (Oct/07) After PreFlash PreFlash Tower Tower Prehe Preheat at Train Train (High Tempe Temperatur rature e – Special Special Metall Metallurgy urgy))
SERVICE
Shear (Pa)
WALL TEMPERATURE (°C)
E-166 A/B (x HVGO)
112
264
E-167 A/B (x HD)
113
289
E-169 C/D (x BPA)
113
295
Petro Pet robra bras s Cu Curre rrent nt Cas Case e
CASE 4
Basic Engineering Design CDU – Grass root Refinery
V
CS
CS
AE V
CS
CS
HT
CB
CB
HT
HT
HT
HT
CB – Co Compa mpablo bloc c CS – Car arbo bon n St Stee eell HT – Hi High gh Te Temp mper erat atur ure e AE – ac acco cord rdio ion n Ef Effe fect ct V – Cr Crud ude e Va Vap por oriz izat atio ion n
PETR PE TROB OBRA RAS S Cur Curren rentt Ca Case se
CASE 4
Basic Engineering Design CDU – Grass root Refinery
COMPARISON OF EQUIPMENT COSTS
SERVICE
Compabloc (US$)
Shell and Tube (US$)
P-10
x
~ 5.6 x
P-11
y
~ 3.8 y
* Installation costs not included; * Equipment designed with the t he same allowable pressure drop; * Compabloc Compabloc design design and budget budget by Alfa Laval; Laval; * Shell Shell and Tube Tube budget budget by Aspen Aspen Icarus Icarus (Brazil (Brazil Base)
Comp Co mpab ablo loc c Des esiign
Design Parameters: – Minimum Shear Stress Stress – Higher Pressure drop drop – Countercurrent Pinch Analysis – Strainers / Maintenance Maintenance facilities – Parallel Arrangement (flexibility) – Accordeon Effect – Crude Vaporization – High temperature temperature
Next Compabloc Tests Next Step at the same refinery: – Operational practice and fouling at high temperatures; – Service: Not defined yet; – Wall temperature above 270ºC (target 300ºC)
Test at Case 2 refinery : w ith – Operational practice and fouling with crude vaporization; – Service: Not defined yet (desalted crude crude vs heavy heavy diesel diesel)) – Crude Temperature from 150ºC to 220ºC
Thank you very much!
Antonio V. S. de Castro,
[email protected] Alan Alan T. Vila Vilas s Boas Boas Claudio L. M. Kuboski Diome iomede des s C. da Sil Silva Roberto A. Oliveira Washington de O. Geraldelli
