Pipe Line Coatings- A review on epoxy based coating

Transcription

1 ICEPIM 2015 International Conference on Pipeline Integrity management Pipe Line Coatings- A review on epoxy based coating By: Rajes Bardia Technical Manager, Protective Coatings 13th March 2015

2 Overview Purpose of pipe lining Challenges Basic requirement of pipe lining Application process Coating Fit for purpose Epoxy based coating Hardeners Polyclamine based coating Summary

3 Pipe line Cost effective transportation of Liquid chemicals Transportation of gasses Prompt and continuous supply Easy to handle heated fluid /corrosive fluid Environment friendly no fuel consumption during transportation

4 Pipe line coating - Basic Purpose Corrosion protection of steel along with cathodic protection system Chemical resistance lining Improved flow Heat resistance Aesthetics

5 Pipe line coating Challenges Continuous service maintenance of coating is difficult Pipe line Installed in remote location Various external factors which can affect coating Internal Coating failure affect downstream operation/economy

6 Pipe line coating Basic Requirements Must meet requirement of suitable specifications like API, ISO BSEN,CSA Must meet critical tests as per ISO /ASTM standards Flexibility Impact resistance Abrasion resistance Chemical resistance Roughness Wet adhesion Cathodic disbondment Suitability on damp surfaces Line parameters and Application properties of coating should match

7 Critical tests Flexibility Most critical for pipe coating if bending is allowed 1.5Deg PDL bending Various Standard available like ASTM D522 Different requirements based on End application

8 Critical tests Impact Resistance of coating to damage from Impact Std test method available in ISO /ASTM Important for pipe line coating to ensure coating continuity during service

9 Critical tests Abrasion Resistance To determine coating performance during exposure to abrasive environment Also to check suitability as internal coating for abrasive media like slurry ASTM D conventional method ASTM G6 accelerated testing

10 Critical tests Chemical Resistance To check suitability of the coating during service condition with various chemicals Temperature of the environment to be considered External factors to be considered for external coating

11 Critical tests Roughness Measured through roughness profilometer Very much critical for gas pipelines Rz values >5 LSA coating are having very smooth finish

12 Critical tests Wet Adhesion test Wet adhesion will ensure adhesion of coating film during immersed condition Hot water soak test

13 Critical tests Wet Adhesion test Wet adhesion will ensure adhesion of coating film during immersed condition Hot water soak test

14 Critical tests Cathodic disbondment test Cathodic protection is a technique to prevent corrosion of metal second line of defence along with coating Can be detrimental to coating cathodic disbonding Testing should be carried at Max. temp.coating is recommended ASTM G8 /ASTM G 95

15 Pipe Line coating application process Coating must be application friendly Major Issues due to application problem Poor adhesion on one side of the longitudinal seam weld. Caused by inadequate surface preparation Pinholes or roughening of the coating. Craters/blistering of the coating. Foaming Strain lines/cracks in the coating. Poor adhesion at the cutback. Leopard spotting in ground Improper curing Sagging Roughness

16 Pipe Line coating Fit for purpose The key elements in ensuring that the coating on new pipeline is 'fit for purpose include: Specifications and qualification Pipe supply Coating plant and inspection Control of coating application Control of site operations

17 Epoxy Based coating Epoxy Normal Tanklining Network Epoxy Phenolic Higher performance Network Epoxy Novolac Tightly Cross linked Network

18 Cross Link Density vs Nomenclature Cross link density is not solely affected by choice of epoxy A low functional amine with an Epoxy Novolac may give an open network as per an normal epoxy A highh functional amine with a normal epoxy may give a tight network Products should be selected on performance not nomenclature

19 Cross Link Density (Simplified) H2O H2O H2O Normal Tanklining Network e.g. EC125LV Free Volume in cross link Network Higher Performance Tanklining Network e.g. EC 376-F-30 Tightly Crosslinked Tanklining Network e.g. EC 405HT Cross link networks are not this idealised There will always be some gaps in the network to allow permeability The tighter the cross linking the smaller and fewer these larger gaps will be.

20 Cross Link Density (Simplified) At ambient temperature the cross linking is sufficient to prevent permeation of water through all the films H2O H2O H2O Free Volume in Network

21 Affect of temperature on Performance At ambient temperature the cross linking is sufficient to prevent permeation of water through all the films Free volume increases in network with higher immersion temperatures due to plasticization from the media Water can permeate the film at a critical temperature H2O Heat > 90 C Heat > 120 C H2O <120 C H2O Tightly Cross linked Tanklining Network EC405HT Increased free volume Due to immersion at higher Temperatures still showing reduced d permeation Water permeation Coating Failure

22 Nomenclature vs Performance The Cross Link Density is related to the type of Epoxy used: Normal Epoxy Epoxy Phenolic Epoxy Novolac This determines the permeability and temperature resistance Specific solvent and chemical resistance is determined by the choice of amine hardener Solvent Resistance Acid Resistance Alkali resistance A Novolac lining for Ethanol will not necessarily resist Sulphuric Acid

23 Hardeners for pipe linings Polyamide - Mainly used for normal application condition for external dry service condition. Cylcoaliphatic li amines Better chemical resistance and more cross link density Aromatic amine - Better resistance properties including heat however banned due to stewardship issue Aliphatic amine - Better chemical resistance however mainly used as adduct. Amido amine Primarily for better chemical resistance and surface tolerant property. Mannich based amines Mainly suitable for curing in damp condition and fast cure at low temperature. Phenalkamine Widely being accepted for better corrosion and chemical resistance as compared to polyamide based coating. Mercaptan Fast cure reaction with epoxy. Stewardship issue Polycylamine - New Technology.Multi functional, higher cross link density, improved chemical resistance

24 Polycyclamine y Cured Lining Technology - Introduction Traditionally tank linings are defined by their generic resins, but it is also important to consider the curative. Polycyclamine Cured Linings are amine cured epoxy linings, which use polycyclamine curing agents to produce high performance characteristics. Utilising multi-functional polycyclamines with reactive sites directly compatible with those on epoxy novolacs leads to increased cross linking of the lining. Increased cross-linking in these linings creates reduced free volume and lower permeation rates than linings cured with traditionally used amines curatives.

25 Immersed Temperature Resistance On heating the free volume in a lining increases in size and eventually allows penetration. Due to increased cross linking polycyclamine cured linings start with smaller free volume and therefore can experience higher temperatures before failure. H2O H2O Traditional amine cured linings Polycyclamine Cured Linings

26 Polycyclamine Cured Lining Technology Superior chemical immersion resistance to a wide range of chemicals (including acids, solvents and hydrocarbons). High temperature immersion service (120 C). Thick film systems for excellent long-term barrier resistance Ultra high solids technology, low to zero VOC s Built on Technical Excellence

27 Quick Return to Service (RTS) Polycyclamine technology offers products with the quickest Return To Service times in their class. The return to full immersion service time is usually next day (as short as 8 hours, typically 12 to 14 hours) and so reduces shutdown times by days in comparison with standard lining technology. An owner in Europe estimated that the shutdown of a Ø78m crude oil storage tank costs 40,000 / day.

28 Possible Uses Possible End-Use Buried Pipeline Field Joint Material NSF 61 / Potable water up to 82 C ( or even higher) Refined Petrochemicals for UST Linings for concrete application Refined Petrochemicals and Crude to 90 C Refurbishment Scheme conforming to API 652/653 Refined Petrochemicals and Crude to 120 C Lining for concrete applications Lining with inorganic acid resistance Buried pipelines for high temperature resistance Good resistance to food and drinks

29 Application Example Buried Pipeline The quick cure of the coating allows quick back filling of the pipe and also reduces the good weather window required to apply the coating. This saved the customer money and allowed quick completion of the job.

30 Summary Selection of coating is very much critical and should be tested as per international specification and test standards Application process must be standardised to avoid coating issues due to application Coating must be tested t at specific line for fit for purpose test t Epoxy amine binder system is still is being widely used as pipe line coating for both external and internal surface Development in amine technology to improve chemical resistance Recent new development -Polyclamine technology

31 Thank You