1. 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

2. 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 Expected performances Actual performances

3. 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

4. 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 0,00,20,40,60,81,01,21,41,6 Leak % Required temperature to reach specification (°C) Feed containing 3500 wtppm S Effluent at 10 wtppm S Effluent at 50 wtppm S Effluent at 350 wtppm S

5. Effluent 28 ppm Effluent + 1%charge 4,6 DMDBTDBT C3 BT Feed-effluent exchanger leak - feed effluent analysis Sulphur compounds specific chromatograph Case 2 – Unit Poor Performances

6. four échangeur S charge S eff réacteur S eff éch A S eff éch B 1 2 3 4 A B

7. Case 2 – Unit Poor Performances

8. Case 2 – Unit Poor Performances PACKINOX Exchangers