Glass lined Reactors Parts Spark test Trouble shooting

Glass lined Reactor is a pressure vessel which has main body made with carbon steel and lined with glass.

Glass lined Reactor is used to handle highly corrosive materials. This reactor is available in one piece configuration and separate 2 piece vessel and agitator is available.

Glass lined Reactors Parts Spark test Trouble shooting

Blog Content

  • Parts of Glass lined Reactor
  • Properties of Glass
  • Spark test in Glass lining
  • Glass lining colour and applications
  • Thermal shock in Glass
  • Typical Glass Failure

Frequently Asked Questions

  1. What is composition of glass lining?
  2. What is Spark test? Why it is required?
  3. In which colors glass is available? What are specific applications of various colors?
  4. What are main reasons of Glass lining failure?

Parts of Glass lined Reactor

Parts of Reactor is same as in Normal Reactor you can read here

Properties of Glass

Glass is lined in reactor with Borosilicate 3.3 

Borosilicate Glass 3.3 compositions

80% Silica
13% Boron oxide
4%   Sodium Oxide
2 - 3% Aluminium Oxide

Boron oxides thermal expansion is very low. It is 5-7 µm/(m·K).

Borosilicate 3.3 glass has low weight density because atomic weight of Boron is low. It is 10.81 g/mol.

Trade names of glass used in lining is known as Simax, Suprax, Kimax, Pyrex, Endral and Refmax.

Borosilicate 3.3 has more capabilities against thermal Shock but too much variation can damage it.

How much we will see in this blog.

Spark test in Glass lining

Spark test is carried in Glass lined Reactor to find out defect or damage.

Frequent test can find minor pinholes and crack and prevent major damage to reactor.

Spark tester came in handheld insulated wire wound device which is properly grounded on Glass lining.

Spark test in Glass lined reactor

Spark test in Glass lined reactor agitator

On crack it shows spark and Audiovisual alarm on tester.

Marking and glass patching carried after test.

Watch video

Glass lining colour and applications

Glass lining is available in various colours but main 4 colours are popular.

1. Blue
2. Light blue
3. White
4. Green

Each glass has different property and application.

1. Blue Glass lining

Dark blue colour is used in high concentrated acids and bases.

It provides maximum protection against concentrated acids and bases.

Blue glass lining reactor
Parts of Glass lined reactor

2. Light Blue Glasslining

Light blue Glasslining Reactor used in Pharmaceutical industry

This colour has better optical monitoring.

Corrosion resistance is low compared to Dark blue colour.

Light blue Glasslining Reactor

3. White Glass lining

White Glass lining is used for that types of Processes in which colours are changing in process.

Accurate monitoring on colour can be possible.

White glass lining reactor

4. Green Color Glass lining

Green colour glass lining is used to handle reactions carried at high temperatures.

Maximum temperature handle in green glass lined Reactor is 270℃

Impacts of Chemicals 

Highly alkaline solutions with high temperature has highest corrosion

We can see graph Glass Lining Corrosion graph Temperature vs pH 

Glass Lining Corrosion graph Temperature vs pH

Excellent resistance to corrosion

Excellent resistance to corrosion

Variable effect depends on actual process

Variable effect depends on actual process

Highest corrosion in glass not recommended


  • If HCl is using in liquid phase in glasslined reactor it will erode 0.01mm / year.
  • HCl in Vapour phase corrode 0.04 mm/year.


  • NaOH is erode 0.21 mm/year.


  • Water erodes 0.008 mm/year in liquid phase.
  • Water vapour erodes 0.013 mm/year.
Erosion is increasing with increase in batch volume and fluid velocity in reactor.

Volume vs corrosion rate

We can see in below graph that corrosion is minimum up to 150℃.

Corrosion resistance graph in glass lining.jpg
Corrosion is increasing with in increasing temperature and alkaline pH.

We can see general Acid base vs Volume below

Acid base vs Glass lining erosion

Thermal shock in Glass

When heating or cooling applied in Glasslined Reactor - temperature difference between reactor inner fluid and heating or cooling should not high.

High difference between inner fluid temperature and heating or cooling source will be damaged due to thermal shock.

Thermal shock in Glass lining Reactor

Thermal shock in Glass lining

Graph 1: Reactor inner fluid temperature vs Heating source temperature.
Graph 2: Reactor inner fluid temperature vs Cooling source temperature.

We can How much temperature difference maximum allowable.

Examples of Glass lining failure

Glass lining side

1. If Glass lined wall temperature is 10°C 
Then fluid inner temperature should be 160°C

2. When Reactor inner temperature is 180°C then Cooling source temperature must above 50°C.

3. When Reactor inner temperature is 0°C then heating source temperature must below 140°C.

4. When Reactor inner temperature is 20°C then heating source temperature must below 170°C.

Physical Characteristics of Glass lining

Corrosion resistance of Glass lining with different chemicals at different temperatures

1. Hydrofloric acid and Floride aqueous solutions can not give resistance to corrosion of glass lining even at 50°C and corrosion is highest.

2. Triethylamine is not corrosive at 50°C temperature and higher corrosive at 100°C

We can see chemicals list at below

Typical Glass Failure

1. Mechanical shock

Mechanical shock is 75% reason for glass failure
  1. Impact due to heavy object fall on reactor
  2. Object fall in reactor. Example: Bolt or metallic parts, stones etc.
  3. Improper support and heavy vibration.
  4. Wrong impeller direction and over torque.

2. Acid attack

Hydrofloric acid and Phosphoric acid or Phosphorus acid with 85% Concentration corrodes glass lining maximum.

Rest Chemicals chart as seen above.

3. Abrasion

Chemical process in Glass lined Reactor with
  • High viscous chemicals
  • Slurry
  • Solid particles contained chemicals reactions
Rubbing surface of glass lining of reactor and making rough like sand paper.

This rubbing breaks silica network and boosting corrosion of glass lining.

4. Thermal shock

We already discussed this topic above.

5. Electrostatic discharge failure

When two components mixed together then they transfer electron and generates static charge.

When proper static is not discharged static accumulation takes place. This static is discharge with pinhole of crack. This damage is continuously damage more glass lining.

Static charge generation can be reduced by
  1. Adding water or quick solvent.
  2. Reduction in agitation.
  3. Adding dip lines for chemical dosing and Avoiding free flow of Chemicals
  4. Proper grounding of Chemical mixture and Reactor.
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Important links
Wikipedia - Read more
Read on Dedietrich
Read on Glass-linng

Photo credits

Buying Links

Thanks for reading - 
Naitik Patel
Industrial Guide

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