ERALY SERVOCOULOMETRE MIPO5: DETERMINATION OF CHLORINE AND BROMINE

Transcription

1 THEME ERALY SERVOCOULOMETRE MIPO5: DETERMINATION OF CHLORINE AND BROMINE 1

2 PLAN I - PROBLEM II - PRINCIPLE 1- Acid formation and corrosion of equipments 2- Asphaltènes formation and poisoning of catalysts 1- Coulometry 2-Minéralization apparatus 3- Titration room III TITRATION MADE 1-Chlorine in gas 2-Chlorine in Naphta 3-Chlorine in crude oil and catalysts 4-Bromine in Heavy distilled 5-Data treatment IV RELIABILITY AND ACCURACY OF COULOMETER 2

3 Acids formation: In the top of column with non-hydrolysable chloride MgCl + H 2O Mg( OH ) 2 + 2HCl 2 2 Problem CaCl + H 2O 2 2 Ca( OH ) 2 + 2HCl Catalysts poisoning Regulation of Reforming catalyst acid function : chlorine must be between 0,9 % and 1,1% of catalyst mass Chlorine content> > 1% of catalyst mass: instability of catalyst witch bring about of it s poisoning by coke Chlorine content < < 1% of catalyst mass: inadequacy of hydrogenation reaction and aromatization 3

4 Principle Coulometry: quantitative measurement of a chemical reaction of hydrolysis Oxidation on silver anode: Ag Ag + + e Precipitation of silver halogen: Ag + + Cl AgCl ou Ag + + Br AgBr Measurement of concentration: by potentiometry at zero current High sensibility: Faraday High resolution: best than 1/1000 4

5 Overall picture of SERVOCOULOMETRE MIPO5 5

6 Principle of method Process: Analysis during 3 steps Mineralization: Pyrolysis/Combustion of sample Absorption: electrolyte absorbs gas of combustion Measurement/ calculation: Halogens quantity measurement by Coulometry 6

7 DESCRIPTION Device: constituted to two furnaces: F1: for sample vaporization, pyrolysis and/or it combustion (T=750 C) F2: it make oxidation of gas from F1. it temperature is maintained at 1000 C 7

8 Titration room: with 4 electrodes Anode: Ag Cathode: Pt or Ni DESCRIPTION Measurement electrode pair: Indicator (Ag pure) et Reference (Mercury sulfate) Titration room: Picture 8

9 ANALYSIS METHOD Method : gas mode Samples: Gas of Hydrogen Unit, Gas of Reforming Unit Description of method: injection of sample into F1 with a gas syringe Method: liquid mode Samples: Naphta Reforming, Heavy GO Electrolytes: Type1 BT «Basse teneur» : content between fractions of ppm and several hundred of ppm Type1 «Moyenne teneur» : some ppm < content < some % Type 2 «Forte teneur» :fractions of %< content < 100% 9

10 ANALYSIS METHOD Description du method: liquid/gas Injection of sample into F1 (750 C) with an automatic injection apparatus before initialized Choice of liquid mode and selection of element which must determined Analysis control with a computer and displaying of result at the end of analysis Titration mode: solid mode Description: use of nacelle for taking and mineralization in F1 F1: Temperature sequence to be defined according to nature and behaviour of sample. 5 segments: Drying phase :segment at 90 C Leave of light products: tendency of 40 C/min until 300 C Ending of pyrolysis: tendency of 200 C/min until 950 C Oxidation of eventual residues: level at 950 C with gas inversion Ending phase: decreasing tendency of -200 C/min until 500 C 10

11 ANALYSIS METHOD Titration mode: direct titration (when sample is inert towards electrolyte): same reactions that previous modes Description: direct injection of samples in titration room without mineralization phase) 11

12 RESULTS Comparative results UOP Method ERALY COULOMETER SAMPLES Result (average in ppm) Standard deviation Remark (Method) Result (average Stand ard deviat ion Remark (Method) Gas Hydrogen Unit Gas Reforming Unit UOP T : reliable but long duration(5h) UOP405-67T:reliable but long duration(5h) Reliable: low duration (20 min) Reliable: low duration (20 min Naphta of Reforming Combustion with WICKBOLD: reliable but safety problem Liquid mode: reliable and accurate Crude oil P287 ASTM D3230 Rapid method Solid mode: reliable and identify only chlorine or only bromine Catalyst of Reforming 0.27 % mass 0.12 TELEX IFP N 3490 reliable but long duration(calcination at 1000 C during 2h) 0.3 % mass 0.09 Solid mode: quick and reliable Heavy GO U85 (Bromine) - - Any titration liquid mode: quick and reliable 12

13 CONCLUSION Reliability: The Coulometer SERVOCOULOMETRE MIPO 5 is reliable Accuracy: Coulometer mostly accurate for analysis in gas mode and liquid mode Benefits for using Servocoulomètre MIPO5: Operating time lower than UOP Method operating times Scope of application more plus extensive ERALY Coulometer: analyses all kinds of samples (choice of titration mode) Error limit (incertitude) because few handlings or operations 13