Assistance Technique Case 1 – Reactor Design

1. Choose main conditions – Pressure, cycle length, type feed, product,

flowrate

2. Catalyst volume

3. Optimum mass flux is set at 2,7 – 3 kg/s/m2

4. Normal pressure drop per bed not higher 3-3,5 bar

5. Set maximum catalyst bed length – 10-12 m

6. Set a maximum catalyst bed exotherm

7. Choose the internals – tray, quench, outlet collector

8. Care should be taken for all shut-down, catalyst unloading and

loading

9. Choosing metallurgy as a function of Pressure, Temperature and

liquid/gas composition

Assistance Technique

Case 2 – Unit Poor Performances

Case 2A - Unit A in France had an apparent activity at 25°C higher than expected

HDS - Evolution of normalised temperature for operating conditions

feed sulphur = 5000 wppm, product sulphur = 200 wppm, LHSV = 1,6 h-1

320

330

340

350

360

370

380

390

400

0 60 120 180 240 300 360

cycle length (days)

no

rmal

ised

tem

per

atu

re (

°C)

Expected performances

Actual performances

Assistance Technique

Case 2 – Unit Poor Performances

Cause analysis

a. Sampling and analysis validity!

b. Bad H2S stripping – H2S recombination

c. Leak or by-pass on a start-up line or a P measurement line

d. Feed-Effluent exchanger leak

e. Impurities in gaz phase

f. Mal distribution

g. Poor catalyst performances

Assistance Technique

Case 2 – Unit Poor Performances

Leak or by-pass confirmation

- Kinetic analysis - Use of chemical tracers

- Pressure drop variation - Use radioactive tracers

320

330

340

350

360

370

380

390

0,0 0,2 0,4 0,6 0,8 1,0 1,2 1,4 1,6Leak %

Req

uir

ed

tem

per

atu

re t

o r

each

sp

ecif

icat

ion

(°C

)

Feed containing 3500 wtppm S

Effluent at 10 wtppm S

Effluent at 50 wtppm S

Effluent at 350 wtppm S

Assistance Technique

Effluent 28 ppmEffluent + 1%charge

4,6 DMDBTDBTC3 BT

Feed-effluent exchanger leak - feed effluent analysis

Sulphur compounds specific chromatograph

Case 2 – Unit Poor Performances

Assistance Technique

Case 2 – Unit Poor Performances

four

échangeur

Scharge

Seff réacteur

Seff éch A

Seff éch B

1

2

3

4

AB

Assistance Technique

Case 2 – Unit Poor Performances

Assistance Technique

Case 2 – Unit Poor PerformancesPACKINOX Exchangers