Electrolyzer basics and membrane replacement

transcript

ELECTROLYZER MEMBRANE REPLACEMENT

ENGINEER MUHAMMAD REHAN

CONTENTSPRE TEST1. EPCL PRODUCT FLOW2. CHLOR ALKALI PLANT PROCESS OVERVIEW3. WHAT IS ELECTROLYSIS?4. WHAT IS A CELL?5. ELECTROLYZER6. ELECTROLYZER’S CELL7. ELECTROLYZER’S MEMBRANE8. PROCESS OF ELECTROLYZER9. ELECTROLYZER’S ASSEMBLING10. MEMBRANE REPLACEMENT11. ELECTROLYZER ‘S SPARES IN WAREHOUSEQUESTIONSPOST TEST

PRE TEST

TERMINOLOGIES• NaCl = Sodium Chloride Salt• BRINE = Sodium Chloride + Water Solution• NaOH = Caustic Soda• H = Hydrogen• Cl = Chlorine Gas• CA = Chlor Alkali Plant

EPCL PRODUCT FLOW

CHLORINE

EDC/ VCM VCM

PVC 1/ PVC 2 PVC

PP/ UTY 1/ UTY 2GAS/

CA PROCESS OVERVIEW

O Not being done at EPCL O

WHAT IS ELECTROLYSIS?• Electro = by electricity• Lysis = break down

• Chemical decomposition produced by passing an electric current through a liquid or solution containing ions

WHAT IS A CELL?• CATHODE• ANODE• MEMBRANE• ELECTROLYTE• BATTERY SOURCE

ELECTROLYSIS OF BRINE

1HClNaOHOHNaCl

ELECTROLYZER ROOM

ELECTROLYZER (R1230A-F)

• 6 Electrolyzers• 119 Bipolar cell• 1 anode cell• 1 cathode cell• 120 membranes• 120 gaskets• 120X4 hoses• 1 Press Unit

ELECTROLYZER CONSTRUCTION

ELECTROLYZER CELL

CELL CONSTRUCTION

Ti metal anode sheetTi metal ribs

Ni metal cathode sheetNi metal ribs

CELL HANDLING

CELL HANDLING• Not to scratch the sealing surface• Not to knock the electrode surface• Handle using the Wooden Spacera) Anode Protrusion =1.5 mmb) Cathode Protrusion = 0.8 mm• Take care of nozzels, sub-header and side

ARM OF CELL• Easy transfer• Quick alignment• Keep aligned

Cell Arm

HYDRAULIC PRESS

• Charging oil grade : ISO VG46• (Viscosity range : 30 ~ 60 cSt.)

Sulfonate Layer1. Mechanical Strength2. High Electric

ConductivityPTFE Web3. Tear Resistance4. High Mechanical

Strength5. RigidityCoating1. Cl2 Gas Releases

Carboxylate LayerHigh ion selective permeability1. Prevent OH- migration (high

current efficiency)2. Prevent Cl- diffusion (low

NaCl in NaOH)Coating1. H2 gas releases

ANODE SIDE CATHODE SIDE

CELL MEMBRANE

Membrane Two Layer Concept • Increases susceptibility to blistering • Responsible for excellent performance of

membrane.

MEMBRANE HANDLING• Numbering of Membrane

• Position of Numbering

AlphatecalLetters

Arabic Numerals

Cathode sidesurface

Numbering

MEMBRANE HANDLING

ELECTROLYZER ASSEMBLING

• How the electrolyzer was assembled• A brief overview….

ELECTROLYZER ASSEMBLING

Hoses Installation

Cell Frame Tightening

Install Membranes

Install Cell Gaskets

Washing Cell Frame

Mounting Cell Frames

Installing Insulation Plate

INSTALLING INSULATION PLATE

MOUNTING CELL FRAME

WASHING CELL FRAME

INSTALLING CELL GASKET1. Preparation

a. Gaskets b. Working Tablec. Adhesive: Bond G-11Z (16.3kg for 120 Cells)d. Thinner: Cyclohexanee. Anti-Sticking agent: TORAY SILICON PRX-306 clear (8.2 kg for

120 Cells)f. Metallic hand rollersg. Waste Clothsh. Wooden framesi. Gasket hangersj. Brushes

INSTALLING CELL GASKETAnolyte Gasket Position

• Anode-Gasket: 0-2 mm• Do not overlap• Do not protrude too much

INSTALLING CELL GASKETCatholyte Gasket Position

• Do not overlap• Do not protrude too much

INSTALLING CELL GASKETAnolyte & Catholyte Gaskets Surfaces

INSTALLING CELL GASKET

Anolyte Catholyte

INSTALLING CELL GASKETGasket’s arrangement for 120 Cells

2. Gasket Sticking

This work requires atleast 7 person• 2 person beside wooden frame• 2 person in electrolyzer• 2 person on electrolyzer sides for carrying gasket and sliding cell frame• 1 person for inspection, coordination and organization of work

• Anolyte Gasket: Cell side up (Adhesion surface)• Catholyte Gasket: Groove side up (Adhesion Surface)

• BOND G11Z

• With Thinner

INSTALLING CELL GASKETGasket Sticking order

3. Applying Anti-Sticking agent

• Apply uniformly on all gasets starting from anode terminal cell frame– Keep Small gap (about 5mm) between each cell frame for drying of Anti-Sticking agent

• Repeat above procedure for all cell frames• Slide all cell frames towards the loose head for membrane installation

– Harderng time of Toray silicon PRX-306 clear is minimum 4 hours. It absorbs mosture from the air and make a thin film on gasket surface

MEMBRANE INSTALLATION

Manpower required = 12 Fitters

5 person: On electrolyzer4 person = On both sides of the electrolyzer2 person = For membrane carrying

1. Submerge the membranes in 2% NaHCO3 Solution2. Adjust Hydraulic Pressure at 10 Kg-F/cm23. Confirm the following:

i. All cells are correctly mounted on the side barsii. Orientation of electrode surface and guide notch is correctiii. Washing of electrode surface and electrolyte compartmentiv. Stucking of gasket and gasket is free from foreign particlesv. Uniform application of anti-sticking agent on gasket surfaces

4. Greas has been applied on the side bars5. 11 Person are ready6. Transfer all cells towards the loose head except centre

terminal cell7. Connect the both side terminal cells to the loose head and

centre terminal cells to fixed head respectively by the clamps

Confirmation & Preparation

1. Insert two locking pins into the holes of cell arms2. Take rolled membrane out from the vat3. Pour DM Water on the anode and cathode faces4. Check the mark of “CATHODE SIDE” on membrane5. Set the membrane on the anode so as its each edge

almost equally protrudes beyond cell frame

Setting Membrane to cells

IMPORTANTa. Softly hold both sides of lower edge of membrane so as to press it

against the anode surfaceb. Be Careful not to make any wrinkles to the membranec. Do not pinch the membrane between the locking pins and the holed. Do not fall down the memrane on the floore. Do not nip your finger in between the cells

Setting Membrane to cells

6. Slide the cells towards the fixed head to fit the guide notch correctly and press the membrane between the cell frame

7. Repeat steps 1-6 for all cells except side terminal cell8. Pour DM Water outside of all membranes after every 30

minutes

MEMBRANE INSTALLATIONSetting Membrane to side termainal cells

1. Set the membrane to the terminal cell as mentioned2. Check that the guide notches are correctly fit3. Move the terminal cell frame with the loose head slowly

by hydraulic pressure4. Press the membrane at 10 Kg-F/cm25. Take off both terminal cells’ clamps6. Increase hydraulic pressure to 70 Kg-F/cm27. Check the guide notches of cells on side bars

MEMBRANE INSTALLATIONPRECAUTIONS

I. Take care of alignment in first time as the correction of alignment after membrane installation may cause damage to the membrane

II. Membrane installation and hose connection work should be done in one go as to avoid the drying of the membrane

HOSES INSTALLATION• Material required

– PFA hoses for inlet/ outlet nozzles– EPDM Gaskets for anolyte and catholyte– Cap nuts for surplus nozzles

• Tools

– Single-ended wrench with 30cm length (46mm for inlet nozzle and 50mm for outlet nozzle)

HOSES INSTALLATION• Inspection of Hose Check for:

– Cracks– Pinholes– Abrasion and other defects– Unusual shape– Uneven thickness– Damages screw thread of hose nut

HOSES INSTALLATION1. Screw the nut of hose by hand

– Anolyte outlet hose will not be installed before “Membrane Leak Test”

2. Tighten the nut by torque wrench with 250 Kg-cm

3. Cap the surplus nozzles

4. Re-tighten the hoses with PVC (FRP) wrench when electrolyzer is on shutdown.

MEMBRANE REPLACEMENT

• Preparation – Mark and verify the position of the membrane to be replaced

– Spare membrane should be ready in the equilibrium liquid

– All cells should be washed and washing water should be discarged

• Note– Given procedure is for the replacement of one membrane. Repeat

the same procedure if more than one membrane replacement is required

– Same procedure will be followed for Cell replacement

MEMBRANE REPLACEMENT• Manpower required 07

– 4 on electrolyzer, 4 on both sides and 1 will operate the press

• Tools required for moving the cell frame– Long chain with quick coupling 04– Short Chain with Grab hook 08– Bolt for fixing quick coupling 08– Clamp with Chains 04– Anti-Sticking agent– Terminal Cell clamp (if necessary) 04– Thin Plastic plates 04– Veneer plate sheet 01– Plastic film sheet 01– PVC Pipes 03– Flexible shower 01– Trays for locking pin 02

MEMBRANE REPLACEMENT Preparation – The Chains arrangementi. Reduce Hydraulic pressure to 10Kg-F/cm2ii. Reduce all inlet hose nuts on cell side iii. Take off the outlet hose from the cells and loose the nuts on the sub-

header side

MEMBRANE REPLACEMENT

4 long chains will be set on the both ends of the tightening device on the press head

4 short chains with grab hook will be set on the M20 bolts and connect the grab hook with long chain

Tighten the long chain by tightening device

MEMBRANE REPLACEMENTiv. Release lock-nut out of threads of the press lock rodv. Pour Water on the membrane to be replaced

MEMBRANE REPLACEMENT1. Hold the membrane on the electrolyzer

2. Draw back the loose head about 25-30 cm

3. Peel off the membrane using thin plastic plates

4. Take out the membrane and spread it with cathode surface up

5. Check the membrane condition

6. Roll it on 50mm dia PVC Pipe

MEMBRANE REPLACEMENT7. Soak the rolled membrane in vat

8. Check sharp point of the anode and the cathode surface

9. If iron powder deposited at the spot welding point, clean them off carefully

10. Wash both anode and cathode by DM Water

MEMBRANE REPLACEMENT11. In case the gaskets have been used for more than 6

months, replace the gaskets

12. In case the gaskets have been used for less than 6 months, check the condition of the gasket

– If condition is Ok, apply the Anti-Sticking agent on the gaskets

– If condition is not Ok, replace the gaskets

13. Install new membrane according to already mentioned procedure

MEMBRANE LEAK TEST

ACTIVITY BAR CHART

NORMAL HOLD POINT CRITICALIF REQD

ACTIVITY BAR CHART

NORMAL HOLD POINT CRITICAL

ELECTROLYZER SPARESS # ITEM DESCRIPTION (for R1230 A-F, Make: AKCC

Japan)QTY INSTALLED/ ELECTROLYZER ITEM CODE

1 Cell MembraneModel: BIPOLAR. Serial # ML-275 Size 1340mm by 2465mm. Type : ACIPLEX (Per Fluoro Carboxlic Acid)

120 2005.0114.0001

2 Cell Anolyte gasket Anolyte Gasket for Bi-polar Cell.. Part Code : FT-915 120 2005.0134.0003

3 Cell Anolyte gasket Anolyte Gasket for Single-polar Cell.. Part Code : FT-925 01 2005.0134.0004

4 Cell Catholyte gasket Catholyte Gasket for Bi-polar Cell.. Part Code : SN-125 120 2005.0134.0005

5 Cell Catholyte gasket Catholyte Gasket for Single-polar Cell.. Part Code : NG-140 01 2005.0134.0006

6 Cell Inlet hose Cell Inlet Hose (6A).. Drawing # HA103003SH 240 2005.0154.0002

7 Inlet hose gasket Inlet Hose Gasket Part Code : IRP32207. 480 2005.0134.0001

8 Cell outlet hose Cell Outlet Hose (28A).. Drawing # HC280872SH 240 2005.0154.0001

9 Outlet hose gasket Outlet Hose Gasket Part Code : IRP44317. 480 2005.0134.0002

10 PDT hose PDT Hose (10A).. Drawing # HA104501SH 2005.0154.0003

POST TEST

THANKS

Electrolyzer basics and membrane replacement

Engineering