AD.15.03.02 Extreme Sampling: Flare Gas Hans-Peter Visser - - PowerPoint PPT Presentation

Analytical Solutions by the Sea

The 61st Annual Symposium of the Analysis Division Galveston Island Convention Center, Galveston, Texas, USA; 24th – 28th April 2016

AD.15.03.02 Extreme Sampling: Flare Gas

Hans-Peter Visser Analytical Solutions and Products BV (ASaP)

Analytical Solutions by the Sea

The 61st Annual Symposium of the Analysis Division Galveston Island Convention Center, Galveston, Texas, USA; 24th – 28th April 2016

Slide 2

Content

• Problems with current installation, effects and root

cause.

• Design criteria.
• Design considerations.
• Tests and field results.

Analytical Solutions by the Sea

The 61st Annual Symposium of the Analysis Division Galveston Island Convention Center, Galveston, Texas, USA; 24th – 28th April 2016

Slide 3

Problems with new flare gas installation

• Problems direct after start-up;

– Plugging of narrow bore sample paths. – Severe fouling of wetted parts in analyzer installation.

Analytical Solutions by the Sea

The 61st Annual Symposium of the Analysis Division Galveston Island Convention Center, Galveston, Texas, USA; 24th – 28th April 2016

Slide 4

Effects

• Probe

– Green crystals found.

• Sample Conditioning System

– Green/gray deposits on filters.

• Analyzer

– Particles in GC valves.

Analytical Solutions by the Sea

The 61st Annual Symposium of the Analysis Division Galveston Island Convention Center, Galveston, Texas, USA; 24th – 28th April 2016

Slide 5

Root cause

• Undersized process seal drums

QT

Analytical Solutions by the Sea

The 61st Annual Symposium of the Analysis Division Galveston Island Convention Center, Galveston, Texas, USA; 24th – 28th April 2016

Slide 6

“Forgotten” first step

• Cycle time existing GC: 4 minutes.
• 1. REASON AND PURPOSE OF MEASUREMENT

Reason of measurement Yes/No Purpose of measurement Yes/No Criticality analyser Yes/No client (external/internal) / Trending / Safety / legalisation / monitoring / / product quality / control / Environment / energy efficiency / alarm / / environmental / trip / Not critical / safety / management / Safety Integrety Level

N/A

process reliability / REMARKS: Process Quality

Analytical Solutions by the Sea

The 61st Annual Symposium of the Analysis Division Galveston Island Convention Center, Galveston, Texas, USA; 24th – 28th April 2016

Slide 7

Analytical requirements and existing installation

Analytical Solutions by the Sea

The 61st Annual Symposium of the Analysis Division Galveston Island Convention Center, Galveston, Texas, USA; 24th – 28th April 2016

Slide 8

Requirements in a nutshell

• Eliminate fouling and plugging.

– Increase total system reliability. – Reduce maintenance.

• Proper sampling.

– Even at upset conditions with process velocity up to 100 m/s. – Lower water content/ water dewpoint without condensing hydrocarbons.

Analytical Solutions by the Sea

The 61st Annual Symposium of the Analysis Division Galveston Island Convention Center, Galveston, Texas, USA; 24th – 28th April 2016

Slide 9

Conceptual thoughts

• A combination of applied fluid dynamics and

existing sampling techniques

Analytical Solutions by the Sea

The 61st Annual Symposium of the Analysis Division Galveston Island Convention Center, Galveston, Texas, USA; 24th – 28th April 2016

Slide 10

Process conditions (worst case)

• Extreme fluid velocity and Reynolds Number

ID Item Description Symbol Value Unit Reference 20 Pressue Pp 0.076 BarG 21 Temperature Tp 60 °C 22 Reference Pressure Pref 1.01325 BarG 23 Reference Temperature Tref 15 °C 24 Mol Weight Mw 25.85 kg/kmol 25 Density @ Process P & T rPp&Tp 1.009 kg/m3 26 Density @ Reference P & T rPref&Tref 1.098 kg/m3 27 Dynamic viscosity h 0.0000137 Pa.s @ Tprocess 28 Flow fvol 61.51 m3/hour 29 Velocity Vprocess 97 m/s 30 Reynolds Number Reprocess 6,418,316 31 Composition xi] 32 Given/required Fast Loop Flow fv, Fast Loop 4.59 l/min 0.076 60 @ BarG / C Remarks Process Data See Tap "Input"

Analytical Solutions by the Sea

The 61st Annual Symposium of the Analysis Division Galveston Island Convention Center, Galveston, Texas, USA; 24th – 28th April 2016

Slide 11

Flow separation

Analytical Solutions by the Sea

The 61st Annual Symposium of the Analysis Division Galveston Island Convention Center, Galveston, Texas, USA; 24th – 28th April 2016

Slide 12

Fluid dynamics

• Supercritical Reynolds number (6.7 x 105)
• Project case Re 6.4 x 106

Probe entrance

Analytical Solutions by the Sea

The 61st Annual Symposium of the Analysis Division Galveston Island Convention Center, Galveston, Texas, USA; 24th – 28th April 2016

Slide 13

Stokes Law

VF VP

DH = 18 ∗ h ∗ Vf rP − rF ∗ g Hence: DH : µm ; Liquid droplet or particle larger than DH will fall out. h : Pa.s ; Dynamic viscosity. Vf : m/s ; Fluid velocity. rP : kg/m3 ; Density particle and/or droplet. rF : kg/m3 ; Density fluid. g : m/s2 ; Gravitational constant

Analytical Solutions by the Sea

The 61st Annual Symposium of the Analysis Division Galveston Island Convention Center, Galveston, Texas, USA; 24th – 28th April 2016

Slide 14

Inclined orientation

VF VP Vv Vh



VV = VF ∗ SINα DH = 18 ∗ h ∗ Vf ∗ SIN rP − rF ∗ g Hence: Vf : m/s ; Fluid velocity. Vv : m/s ; Fluid velocity vertically. Vh : m/s ; Fluid velocity horizontally.  :  ; Angle probe

Analytical Solutions by the Sea

The 61st Annual Symposium of the Analysis Division Galveston Island Convention Center, Galveston, Texas, USA; 24th – 28th April 2016

Slide 15

Gravity separation

72 Density entrained liquid rel 1800 kg/m3 73 Particle seperation DH 37 µm Sulphur particles Particles smaller than DH will pass 72 Density entrained liquid rel 2170 kg/m3 73 Particle seperation DH 33 µm Salt particles Particles smaller than DH will pass ID Item Description Symbol Value Unit Reference 60 Fall-back tube OD ODFBT 1.05 Inch 61 Tube wall thickness TWTFBT 0.083 Inch 62 Fall-back tube factor 20 2 63 Total length fall-back tube LFBT 449.07 mm 64 Probe angle FBTangle 60  65 Volume wetted parts VolFBT 0.1778 L 66 Velocity VFBT 0.19 m/s 67 Reynolds Number ReFBT 320 1: page 81, (Table II.2) 68 Flow type Laminar 69 Pressure drop dPFBT 0.08 Pa

Darcy equation

70 Lag time @ process conditions LTFBT 2.32 s 71 Lag time @ reference conditions LTFBT,ref 2.13 s 72 Density entrained liquid rel 998 kg/m3 73 Particle seperation DH 49 µm Remarks Stokes Law Falling Section Sch 10 Min.16xID or 400 mm Water "particles" Particles smaller than DH will pass 3/4" Nominal Bore Falling from top downwards

Analytical Solutions by the Sea

The 61st Annual Symposium of the Analysis Division Galveston Island Convention Center, Galveston, Texas, USA; 24th – 28th April 2016

Slide 16

Self draining

Analytical Solutions by the Sea

The 61st Annual Symposium of the Analysis Division Galveston Island Convention Center, Galveston, Texas, USA; 24th – 28th April 2016

Slide 17

Pressure drop and lag time

ID Item Description Symbol Value Unit Reference 40 Insertion depth in process line Insprobe 100 mm 10.94% of ID main line 41 Probe diameter ODprobe 1.05 Inch 42 Schedule TKNprobe 0.219 Inch 43 Total length Lprobe 276.60 mm 44 Probe angle Prangle 60  45 Volume wetted parts Vw p,pr 0.052 L 46 Velocity Vprobe 0.40 m/s 47 Reynolds Number Reprobe 462 1: page 81, (Table II.2) 48 Flow type Laminar 49 Pressure drop dPprobe 0.20 Pa

Darcy equation

50 Lag time @ process conditions LTprobe 0.69 s 0.076 60 @ BarG / C 51 Lag time @ reference conditions LTprobe,ref 0.63 s 1.01325 15 @ BarG / C Remarks 3/4" NB Sch 160 Falling from top downwards Probe

Analytical Solutions by the Sea

The 61st Annual Symposium of the Analysis Division Galveston Island Convention Center, Galveston, Texas, USA; 24th – 28th April 2016

Slide 18

Design flare gas probe

Analytical Solutions by the Sea

The 61st Annual Symposium of the Analysis Division Galveston Island Convention Center, Galveston, Texas, USA; 24th – 28th April 2016

Slide 19

CFD Analysis by VSL Dutch Metrology Institute

Reduced pressure; suction effect

Probe entrance P= 108,000 Pa

Analytical Solutions by the Sea

The 61st Annual Symposium of the Analysis Division Galveston Island Convention Center, Galveston, Texas, USA; 24th – 28th April 2016

Slide 20

Sample extraction

Analytical Solutions by the Sea

The 61st Annual Symposium of the Analysis Division Galveston Island Convention Center, Galveston, Texas, USA; 24th – 28th April 2016

Slide 21

Proof of principle 1

Analytical Solutions by the Sea

The 61st Annual Symposium of the Analysis Division Galveston Island Convention Center, Galveston, Texas, USA; 24th – 28th April 2016

Slide 22

Proof of principle 2

Analytical Solutions by the Sea

The 61st Annual Symposium of the Analysis Division Galveston Island Convention Center, Galveston, Texas, USA; 24th – 28th April 2016

Slide 23

Mission accomplished

Quote: “I forgot to specify. Obviously I meant filters clean in presence of several upsets. We had 3 upsets and several small discharges since the installation.” unquote.