We will explain the basics of glass lining equipment, which is often used in batch chemical plants.
Since it has high corrosion resistance and is inexpensive, it will be kept as basic equipment in the plant.
In order to use the product for a long time, the manufacturer’s technical data is important, but it would be better to have information from the user’s perspective as well.
We have summarized the basics of glass lining equipment from a certain user’s perspective.
I think it’s quite biased…
Glass lining equipment is general-purpose
Glass lining is often used in batch chemical plants.
In terms of versatility, it can be said to be the basis of batch chemical plants.
There are two reasons why glass lining equipment has secured a general-purpose position in batch chemical plants.
Advantages of glass lining equipment
- High acid resistance
- Production cost is low
Everywhere you look in a batch chemical plant, you’ll see large stirring tanks sitting there with a thud.
Almost all of this is glass-lined equipment .
In addition, the surrounding connecting pipes are also usually glass lined pipes. Or it’s fluorine resin lining piping.
Equipment configured with glass lining can handle almost any production item.
Truly a multi-plant.
Switching production is common in batch-type chemical plants, so versatility that can handle any product is very important.
High acid resistance
The greatest feature of glass lined equipment is its high acid resistance.
Is it preferable to use an acid-based reaction process or an alkaline-based reaction process?
I don’t know much about the world of organic synthesis, but I find it easy to use the unique facilities that are strong even with just acids and strong with just alkalis .
Much better than equipment that is half-baked for both acids and alkalis.
Acid has the impression that it is a substance that reacts easily.
A good example is halogen type (F, Cl, Br, I).
High corrosion resistance is extremely important in chemical plants where corrosivity varies depending on the process.
Glass lining with high acid resistance is easy to understand in the sense that we should focus on acid here.
Production cost is low
Glass lining equipment is cheap .
This is easy to understand if you compare stainless steel equipment.
Glass lined equipment and stainless steel equipment are much cheaper than glass lined equipment .
This is due to the cost of the base material .
The base material of glass lined equipment is iron , but the base material of stainless steel equipment is stainless steel .
Glass lined equipment is made of thin glass reinforced with iron, and stainless steel equipment is made of stainless steel.
Glass + Iron > Stainless Steel
That’s the cost structure.
Cheapness is almost absolute justice in capital investment.
important point
Glass lining equipment that occupies a general position in batch chemical plants.
It is not possible to use it without letting go, and there are points to note.
crack
Glass lining equipment will break.
Glass is breakable.
If you drop metal, it will break
If you try to break glass lined glass by human power, it will be quite difficult.
It won’t break even if you hit it a little with a metal hammer. A certain amount of force is required.
However, it is possible to easily break the glass of the glass lining equipment by an unexpected method.
drop the tool
Only this.
Just hitting the outside of glass lining equipment with a tool such as a wrench or chisel from a height of about 1 meter can make you wonder if you have broken the glass.
This is not only because the tool has protrusions , but also because the glass lining itself is vulnerable to external forces .
Be careful when using tools for work or construction.
Beware of fragility
It will crack if fed at high pressure.
If liquid is received at high pressure in the glass lined equipment, it may break.
Considering the case of feeding with a pump, it works with density and lift .
Pay attention not only to the pump head but also to the density.
There is also a type where the insertion tube installed in the nozzle hits the tank wall instead of dropping it directly onto the tank bottom.
The idea is to mitigate the impact even a little when the liquid hits the bottom of the tank.
Will crack if subjected to temperature changes
If the glass lined equipment is subject to sudden temperature changes, it will crack.
Specifically, it is stated in the manufacturer’s catalog, but it is better to be aware that there is a temperature difference of about 100 degrees Celsius between the inside and outside of the equipment.
Be careful when using reactor-type glass-lined equipment with a jacket and placing water at room temperature inside and steaming the jacket.
Even with this alone, if you don’t think about the amount of liquid or the temperature of the steam, it will break easily.
Piping will crack if force is applied to it.
If excessive force is applied to the glass lining, it will break.
A typical example is a nozzle.
If the piping is poorly constructed, excessive force to fix the piping may be applied to the nozzle and cause it to crack.
There are many cases where the header is set up like this.
This is the same as the support point of the cantilever when viewed from the nozzle.
A moment is added to the nozzle, isn’t it?
It is not uncommon for the nozzle glass to break from this.
Add support to the end of the pipe opposite the nozzle.
In factories with many switching pipes, this alone may not be enough support.
This is something to keep in mind when designing piping .
leak
Glass-lined equipment leaks from unexpected places.
Although it does not leak from the glass part of the main unit, it is dangerous to think that it will not leak from anywhere .
leaking from tank nozzle
Glass-lined tank nozzles are prone to leaks.
- The accuracy of the nozzle itself is not good.
- The glass lining itself does not have flatness
- The glass itself is slippery and the gasket shifts
- The contact area of the gasket is smaller than that of the piping.
There is a problem like this, the gasket of the tank nozzle is relatively easy to leak.
Unfortunately, not many good gaskets have been developed around the world. There are things that are expensive and difficult to procure.
Academic-minded people only recommend unrealistic things like this, and don’t even propose realistic ideas. Because I don’t want to take responsibility.
Although it is unlikely that the liquid itself will leak from the tank nozzle, gas may leak.
Especially for glass lining, you should use a PTFE gasket, but chlorine gas will leak.
A typical example of a leak is a manhole with a large diameter .
leaking from the shaft seal
Be careful if there is a shaft seal even in glass lined equipment.
It is better to think that it will leak from the shaft seal.
A small amount, though.
Dry sealing is the basic method for glass lined equipment .
For gland seals, gland wear occurs as foreign matter, and for mechanical seals, cooling water occurs as foreign matter.
A dry seal will not generate foreign matter, but it may leak.
I still use dry seal well.
Conversely, glass lining equipment should be used because it is permissible for such a large amount of leakage.
leaking from the bottom of the tank
The bottom of the tank will open and close with a flush valve or ball valve.
There is a very high chance that you will escape from here.
This is because there is likely to be solids in the reaction process.
Powder tends to accumulate at the bottom of the tank, and even powder that dissolves in the solvent may settle due to insufficient agitation.
If the flush valve or ball valve is opened and closed in this state, solid matter will stick to the valve seat and impair the sealing performance.
cracks due to acid shock
If the outer surface of the glass lining is exposed to acid, the glass will crack .
It must be strange.
The base material is usually iron. When acid adheres to the outer surface of iron, hydrogen is generated by the reaction between iron and acid.
It would be nice if all the hydrogen generated at the moment of reaction was released to the outer surface, but there are cases where this is not the case.
As reactions occur on the outer surface of the iron, reactions also progress on the inner surface, and hydrogen may be generated at the contact between the iron and glass.
This is troublesome.
Even if glass is tightly bonded to iron to ensure its strength, if gas is generated from the close contact, the glass will break.
This is because glass is generally strong against forces from the inside of the container, but weak against forces from the outside of the container.
corrode
Glass lined equipment corrodes.
Even though it’s glass, it corrodes.
Glass only increases its lifespan against corrosion. Overconfidence is prohibited.
Corrosive if the acid is strong
Even though it is a glass lining, it is naturally susceptible to corrosion if the acid is strong .
It’s the most basic of basics, but it’s surprisingly easy to ignore.
Corrosive if alkali is strong
Glass is weak against alkalis, so strong alkalis will corrode it.
It is weaker against alkali than acid, so pH control is one of the important control indicators during operation.
When dropping caustic soda in a reaction, there are a number of points that need to be controlled, such as the method of dropping and the flow rate.
Corrosive even in pure water
It is easy to understand that acids and alkalis corrode glass, but pure water can also corrode glass.
Batch-type chemical plants usually have few opportunities to use pure water, but there may be opportunities to use it in pharmaceutical and semiconductor plants.
Pure water is fine! Please do not misunderstand.
When you write it like this, it becomes difficult to understand what glass lining is strong against.
I’m pretty sure it’s acid resistant . Don’t forget the basics!
Corrodes at high temperatures
Temperature is one of the factors that promotes corrosion reactions.
Naturally, the higher the temperature, the more likely it is to corrode.
There is a famous story that the reaction rate doubles when the temperature rises by 10℃.
Glass linings should also be checked for corrosivity when temperatures exceed 100℃.
low applicability
Glass lining equipment does not have high applicability .
Due to the nature of lining, it is not possible to create complex shapes.
With reactors made of iron or stainless steel, you can design almost anything you want, so if you compare them, you’ll notice that you can’t make them into the shape you want.
If you change the good side, it means versatility .
Versatile equipment is essential for increasing the competitiveness and maintenance capabilities of chemical plants.
I don’t think you need to think too negatively.
lastly
We have explained the basics of glass lining equipment, which is often used in batch chemical plants.
It has the advantage of being highly acid resistant and cheap.
It has the disadvantages of being easily broken, leaking, and corroding, so you need to be careful when using it.
Naturally, this is an important point in equipment design and piping design.
Please feel free to post any concerns, questions, or concerns you may have regarding the design, maintenance, and operation of chemical plants in the comments section. (The comment section is at the bottom of this article.)
*We will read all comments received and respond seriously.