View
224
Download
0
Category
Preview:
Citation preview
8/10/2019 Brazil 2014ugm Performance of Hydrotreating High Pressure Heat Exchanger
1/38
Internal Sealing Performance of a
Hydrotreating High Pressure Heat Exchanger
Rafael Pavan Bagagli
21/05/2014
8/10/2019 Brazil 2014ugm Performance of Hydrotreating High Pressure Heat Exchanger
2/38
Summary
Company Overview;
Problem Description;
Methodology;
Goals;
Conclusions.
8/10/2019 Brazil 2014ugm Performance of Hydrotreating High Pressure Heat Exchanger
3/38
Company Overview
REPLAN Paulnia Refinery
Capacity: 420 mbpd
Location: Paulnia - SP
8/10/2019 Brazil 2014ugm Performance of Hydrotreating High Pressure Heat Exchanger
4/38
Problem Description
HDT Reaction Section simplified flowchart:
Feed
(S2000)
HDD
(S10/S500)
HHPHE
Furnace
Reactor
#1
Reactor
#2
H2
H2 H2
8/10/2019 Brazil 2014ugm Performance of Hydrotreating High Pressure Heat Exchanger
5/38
Problem Description
What is a HPHE?
8/10/2019 Brazil 2014ugm Performance of Hydrotreating High Pressure Heat Exchanger
6/38
Problem Description
Why contamination of hydrotreated Diesel
occurs?
Loss of internal gasket
sealing
8/10/2019 Brazil 2014ugm Performance of Hydrotreating High Pressure Heat Exchanger
7/38
Problem Description
Main questions:
Why gasket looses sealing?
How can we fix it?
LETS CREATE A NUMERICAL MODELAND EVALUATE!
8/10/2019 Brazil 2014ugm Performance of Hydrotreating High Pressure Heat Exchanger
8/38
Methodology: Physical Model
Physical model of HHPE is similar to springs in
series:
8/10/2019 Brazil 2014ugm Performance of Hydrotreating High Pressure Heat Exchanger
9/38
Methodology: Physical Model
Balancing the forces:
SgT is the THEORETICAL gasket stressconsidering uniform distribuiton of Won gasket
surface.
FGFH
8/10/2019 Brazil 2014ugm Performance of Hydrotreating High Pressure Heat Exchanger
10/38
Methodology: Physical Model
Bolt assembly selection criteria:
ASME: 1,8 ksi (12,5MPa) Min: 6,0 ksi (40MPa) Max: 60,0 ksi (420MPa)
8/10/2019 Brazil 2014ugm Performance of Hydrotreating High Pressure Heat Exchanger
11/38
Methodology: Physical Model
And how about diferential thermal expansion?
Operation temperature: 360C;
Heat expansion coeff. of internals (300SS)
greater than channel (1 1/4Cr1/2Mo);
Diferential thermal expansion (~1,79mm) will
tension the channel and compress internals.
8/10/2019 Brazil 2014ugm Performance of Hydrotreating High Pressure Heat Exchanger
12/38
Methodology: Physical Model
Diferential thermal expansion force (FDTE) IS
NOT ADDEDto initial bolt load (W);
Internals behave like springs in series, so the
GREATERof them (W or FDTE) predominate;
Then, how define the sealing force? WILL
SEE BEFORE.
8/10/2019 Brazil 2014ugm Performance of Hydrotreating High Pressure Heat Exchanger
13/38
Methodology: Numerical Model
The numerical model was developed
considering solid elements and geometry,
material and contact nonlinearities;
Were modeled only the gasket, tubesheet,
partition and internal jack screws;
8/10/2019 Brazil 2014ugm Performance of Hydrotreating High Pressure Heat Exchanger
14/38
Methodology: Numerical Model
Components modeled:
Gasket
Partition BoxJack
Screws
Tubesheet
8/10/2019 Brazil 2014ugm Performance of Hydrotreating High Pressure Heat Exchanger
15/38
Methodology: Numerical Model
Geometry and mesh:
8/10/2019 Brazil 2014ugm Performance of Hydrotreating High Pressure Heat Exchanger
16/38
Methodology: Numerical Model
Stiffness of non-modeled componetsconsidering linear elastic materials and no
bending:
It was computed changing jack screw Young
Modulus:
8/10/2019 Brazil 2014ugm Performance of Hydrotreating High Pressure Heat Exchanger
17/38
Methodology: Numerical Model
Details of material models:
* Modified Ey considering non-modeled components rigidity
Material SA-240 TP 347 SA-387 Gr11 SA-453 660B
Model EP kinematic hardening EP kinematic hardening Linear-elastic
Temperature (C) 22 360 22 360 22 360
Yield StrenghtSy (MPa) 276 185 380 316 655 601
Tensile Strenght Su
(MPa)586 480 586 505 965 922
Young Modulus
Ey (MPa) 194994 171358 204084 181844 65281* 57644*
Poisson Ratio 0,3 0,3 0,3 0,3 0,3 0,3
8/10/2019 Brazil 2014ugm Performance of Hydrotreating High Pressure Heat Exchanger
18/38
Methodology: Numerical Model
Stress-Strain curves (Ramberg-Oosgod model):
8/10/2019 Brazil 2014ugm Performance of Hydrotreating High Pressure Heat Exchanger
19/38
8/10/2019 Brazil 2014ugm Performance of Hydrotreating High Pressure Heat Exchanger
20/38
Methodology: Numerical Model
Supports:
Frict ionlesson symmetry surfaces;
Frict ionlesson gasket surface oposite to the
tubesheet;
Fixed Suppo rton jack screw surfaces
oposite to the partition.
8/10/2019 Brazil 2014ugm Performance of Hydrotreating High Pressure Heat Exchanger
21/38
8/10/2019 Brazil 2014ugm Performance of Hydrotreating High Pressure Heat Exchanger
22/38
Methodology: Numerical Model
Boundary conditions visualization:
8/10/2019 Brazil 2014ugm Performance of Hydrotreating High Pressure Heat Exchanger
23/38
Goals: Part 1 Gasket Loads Evaluation
Object ive:
Evaluate influence of Wand FETDon gasket
stress.
Methodology:
Evaluation of Load x deflection (response)
curve
8/10/2019 Brazil 2014ugm Performance of Hydrotreating High Pressure Heat Exchanger
24/38
Goals: Part 1 Gasket Loads Evaluation
8/10/2019 Brazil 2014ugm Performance of Hydrotreating High Pressure Heat Exchanger
25/38
Goals: Part 1 Gasket Loads Evaluation
After heating up FETDpredominate over W;
Maximum load (GPD) is about 2,15e7N,
resulting ~ 23ksigasket stress (theoretical);
Increase W
Use ferritic materialCounter Measure
Reduce gasket widthCounter Measure
8/10/2019 Brazil 2014ugm Performance of Hydrotreating High Pressure Heat Exchanger
26/38
Goals: Part 2 Gasket Stress Distribution
Object ive:
Evaluate gasket stress distribution on gasket
surface
Methodology:
Evaluation of pressure on gasket x tubesheet
contact pair
8/10/2019 Brazil 2014ugm Performance of Hydrotreating High Pressure Heat Exchanger
27/38
Goals: Part 2 Gasket Stress Distribution
Load sequence:
Determ ined from Load x Def. Curve
8/10/2019 Brazil 2014ugm Performance of Hydrotreating High Pressure Heat Exchanger
28/38
Goals: Part 2 Gasket Stress Distribution
Resultant gasket stress:
DISTRIBUTION
IS IRREGULAR
8/10/2019 Brazil 2014ugm Performance of Hydrotreating High Pressure Heat Exchanger
29/38
8/10/2019 Brazil 2014ugm Performance of Hydrotreating High Pressure Heat Exchanger
30/38
Goals: Part 3 Gasket Stress Distribution
Reduced stiffness on holes area promote:
Bending of partition;
Loss of partition x tubesheet contact areas;
Reinforce partition holesCounter measure
8/10/2019 Brazil 2014ugm Performance of Hydrotreating High Pressure Heat Exchanger
31/38
Goals: Part 3 Gasket Stress Distribution
Proposals for project improvement:
1. Reduce gasket width + increase W;
2. Change partition material to 1 1/4Cr1/2Mo;
3. Insert reinforcement on partition holes;
Increase gasket s tress
Reduce temp. inf luence
Improve gasket s tress dist r ibut ion
8/10/2019 Brazil 2014ugm Performance of Hydrotreating High Pressure Heat Exchanger
32/38
Goals: Part 3 Gasket Stress Distribution
New geometry:
Original Partition
New Partition
8/10/2019 Brazil 2014ugm Performance of Hydrotreating High Pressure Heat Exchanger
33/38
Goals: Part 3 Gasket Stress Distribution
New load sequence:
Sg= 30 ks i (Theo retical)
8/10/2019 Brazil 2014ugm Performance of Hydrotreating High Pressure Heat Exchanger
34/38
Goals: Part 3 Gasket Stress Distribution
New gasket stress distribution:
Mn. OK
Mx. OK
Stress distribution along gasket width (0):
8/10/2019 Brazil 2014ugm Performance of Hydrotreating High Pressure Heat Exchanger
35/38
Conclusions
For low bolt loads (W) diferential thermalexpansion load predominates and increase
gasket stress(Sg);
However sealing performance depends on
Top, wich is not uniform for all exchangers and
can vary with process conditions;
8/10/2019 Brazil 2014ugm Performance of Hydrotreating High Pressure Heat Exchanger
36/38
Conclusions
Changing partition material to ferritic,reducing gasket width and increasing W,
eliminate Top dependence;
However gasket stress distribution is
irregular, wich decrease sealing performance
in some areas;
8/10/2019 Brazil 2014ugm Performance of Hydrotreating High Pressure Heat Exchanger
37/38
Conclusions
Inserting a reinforcement on partition holesand increasing shell thickness improve gasket
stress distribution;
Thus, a minimum of 6ksi gasket stress is
achieved in critical regions and leaking
probability during operation is quite reduced.
8/10/2019 Brazil 2014ugm Performance of Hydrotreating High Pressure Heat Exchanger
38/38
Conclusions
QUESTIONS?
THANK YOU!
Recommended