restoring efficiency to glass-lined reactor jackets.
Almost all pharmaceutical manufacturing facilities in the world use lined reactors because they can easily clean and resist most chemicals.
Reactors used during the pharmaceutical process must be thoroughly cleaned between batches to ensure product purity and to prevent product build-ups that may cause heat transfer resistance.
The high surface finish provided by the glass lining makes the use of non-corrosive, low-
Pressure regulating system.
Glass can also be used for years when exposed to chemicals that can quickly cause most metal containers to be unusable.
The Aggressivereaction environment can reduce product purity by dissolving metal from an unlined soft steel or alloy reactor.
In contrast, glass liners can effectively protect base metals so that the heat transfer fluid used in the jacket space usually strikes the jacket and reactor externally before the reaction environment damages the inside of the container.
The technology to reduce corrosion in the outer space of the coat, of course, exists, but is not often implemented.
Productivity is usually given a higher priority and the response scheme is as simple as possible.
From the perspective of corrosion and deposition control, it is ideal to have a properly suppressed fluid that can be used as a heating and cooling medium.
However, it is faster to use steam and water to heat and cool.
For rapid cooling, there is a mechanically cooled solution of ethylene glycol or brine.
In typical applications, steam, cooling water, and freezing solutions may all be used in the same jacket at different times of the reaction cycle.
This is very effective from a production point of view, but the impact on the mechanical system may be compromised.
Good process design can lead to poor corrosion and deposition control.
Consider a typical batch heating process.
Normally, steam is injected directly into the jacket space until the desired reaction temperature is reached.
If the target temperature is lower than the boiling temperature, the steam will be condensed into water that is basically pure.
This condensate is very corrosive to carbon steel and can corrupt the metal in the jacket space.
After the heating cycle is completed, the cooling fluid controls the reaction temperature through the jacket.
This fluid is usually alkaline ordinary plant serving water, containing high levels of dissolved minerals such as calcium, magnesium, silicon and iron.
These minerals have retrograde solubility and are not easy to dissolve at high temperatures.
Therefore, deposition may occur in the housing space on the reactor wall where the surface temperature rises.
The deposition of minerals on steel is a problem for two reasons: first, the mineral scale hinders the heat transfer and the heat transfer will extend the batchtimes;
Second, the soluble ions in the water, such as chlorine and sulfur salts, gather under the sediment.
These ions increase the solubility of iron, resulting in corrosion under the so-called deposition.
Corrosion under deposition is actually just a special case of crevicecorrosion, a form of concentration
Battery corrosion that may result in a high degree of local metal loss.
In addition to introducing minerals into the reactor jacket space, cooling water usually also introduces oxygen.
Oxygen, like most gases, is more soluble at lower temperatures.
Oxygen is released when cold water touches the wall of the hot reactor.
Because oxygen is an antioxidant, it contributes to a corrosion that is considered to be an oxygen hole or oxygen corrosion, which is a common cause of metal perforation in the heating area of the water system.
After the reaction is completed, there is a cooling cycle and the temperature is lowered to the intended target.
Once these ecool products are transferred out of the container, the reactor is ready for another operation.
With the accumulation of jacket dirt, the heating and cooling cycle time can be significantly extended due to increased heat transfer resistance.
Although corrosion and dirt directly increase the cycle time and reduce the production efficiency, they can lead to more serious problems. Glass-
The rated pressure of the liner reactor is usually a specific maximum pressure.
If the wall thickness is reduced too seriously due to extreme losses, the code may ask the vessel to cancel
Low rated pressure.
If the pressure is lower than the process requirement, the reactor may have to be removed from use.
These problems are well known in the pharmaceutical industry, where acid cleaning is the most common corrective action for reactor shell corrosion and dirt.
Pickling, however, symbolizes the single atomic hydrogen when theinherent glass is damaged ([H. sup. 0])
Nondescript, very small, penetrated into steel from jacketside.
When hydrogen atoms arrive at the metal/glass interface, they react to form molecular hydrogen ([H. sup. 2]).
With this reaction, there are about five.
Double the volume.
Over time, the pressure generated will result in glass debris.
Because the original chip is crescent-shaped and very similar to a small fish scale, the term \"fish scale\" is often used to describe the process.
This fish scale damage extends from the base metal to the surface through a glass coating.
Therefore, the integrity of the glass liner in terms of corrosion resistance is completely damaged.
Because of fish scales
Types of cracks usually extend to a considered area, and it is almost impossible to remove the vessel from the service and ship it to a qualified repair facility for re-repair
Glassing is a process of costly maintenance costs and loss of productivity.
If the corrosion is serious and the wall thickness is reduced in a large area, this may be the cost-
It is forbidden to repair vessels in accordance with the original specifications.
Replacement may be a more economical option.
The risk of heat transfer fish scale in a safe recovery reactor is proportional to the hydrogen penetration rate through the reactor wall and the contact time of the jacketcleaning medium.
Whether it is the use of strong mineral acids, or the use of mild inhibiting fatty acids, hydrogen penetration has proved to be meaningful.
Therefore, the safest cleaning of the reactor housing is neutral or alkaline, not acidic.
However, in practice, the effect of alkaline cleaning products on mineral scale is small, while mineral scale needs to be removed to restore heat transfer efficiency.
A neutral pH cleaning procedure * has been developed, recommended by major manufacturers of glass
Lining equipment is a safe and effective way to clean the reactor coat space.
This neutralpH cleaning program is designed to remove iron or calcium
When keeping pH between 6, based on foul. 5 and 7. 5.
Because it produces an unmeasurable hydrogen flux through soft steel, the risk of damage to fish scale glass is almost non-existent.
To date, there is no known glass lining fault using this material.
Case study: iron oxide contaminated pharmaceutical reactor a leading pharmaceutical manufacturer uses several types of glass
The Linedsteel reactor is in the process of its production.
Normally, the factory operates at full capacity under the limitation of the current process cycle time.
The heating and cooling requirements for the production process are very strict, and changes in heating and cooling times have a negative impact on product quality and yield.
The reaction equipment is served by a variety of common fluids including steam and cooling water.
After years of use, the reactor housing was seriously polluted by iron oxide deposits, resulting in production problems.
The process batch cycle is extended and the product quality is reduced without meeting the strict requirements and cooling requirements.
At the same time, due to the speed of production is not fast enough, production efficiency has dropped significantly.
Plant personnel know that removal of sediment is the only way to restore productivity in addition to replacing the reactor.
However, they are reluctant to carry out any type of acid cleaning because of the danger of excessive acid corrosion in fish scales and meters steel jackets.
There are good reasons for this concern.
If acid cleaning is not properly neutralised and the reactor housing is rinsed and re-inspected, acid hiding can result in serious metal loss, making the container unusable under the same pressure.
In the past, the factory tried to use caustic soda. based cleaning.
While glass lining and base metal are safe, it is not effective in removing mineral scale.
The factory staff consulted several experts on the glass issue.
Lining reactor including factory equipment manufacturer.
Experts have recommended the new neutral pHcleaning procedure as the only way to remove iron oxide contamination, which is planned to be carried out within five years
Day period including set
Cleaning and post cleaning
Inspection of glass lining. Prior to theon-
The cleaning company analyzed the sediment samples in the on-site service to determine their source and select the appropriate neutral pH cleaning chemicals.
The cleaning team also measured the ultrasonic thickness of the container wall and coat itself to determine the extent of the damage.
Glass damage, wear patterns, debris or etching inside the reactor were examined.
In addition, spark tests were conducted to ensure that there was no \"holiday (pin holes)
In the glass lining
To confirm that the lining is within the specification, the thickness of the glass has also been measured.
The cleaning team then began to actually clear the sediment.
They connected a custom one.
A cleaning slide is installed on the jacket pipe and the cleaning solution is cycled through the jacket for 72 hours.
During this period, we conducted a comprehensive monitoring of the pH and concentration of the cleaning solution.
In addition, the iron content in the clean solution was measured to verify that the solution is removing iron oxide.
As corrosion products are removed from the housing and reactor walls, the iron content will rise.
Once the system drops to the bare metal, the iron concentration in the cleaning solution no longer increases.
After the cleaning phase is completed, the solution flows out of the system and is discharged through the drain pipe.
Because acid is not used, there is no need to deal with hazardous waste and no separate neutralization steps are required.
Before reconnecting the system, the conditions and direction of the stirring nozzle and plate were evaluated.
The cleaning team recommends severalways to improve reactor life and water treatment in the jacket system.
The reactor then resumed operation.
When the plant evaluates the overall impact of cleaning on its production process, the benefits are considerable.
* The direct result of cleaning is that the operating efficiency of the reactor has increased by more than 30%. * Cool-
Downtime per batch was reduced by 45%. * Heat-
The rise time decreased by 27%.
* Production increased by more than 5% due to the short batch time.
* Improved product quality through better temperature control.
Due to the new increase in heat transfer coefficient, the process temperature is now becoming more sensitive.
* Effective removal of corrosion points and deposits improves the life of the equipment.
The active corrosion battery was stopped.
With the removal of sediment, corrosion inhibitors can reach the metal surface and promote the formation of protective film.
* Realized savings are calculated at $430,000 per year.
Case study: iron oxide-contaminated chemical reactor a chemical manufacturer in Tennessee uses a combination of steam and cooling tower water to heat and cool glass
The lining reactor used in the company\'s production process.
The constant switching between steam and cold water accelerates the corrosion of iron, and iron oxide deposits to the extent that the heat transfer efficiency is greatly reduced.
Due to the direct result of dirt, the batch time has increased.
Removal of iron oxide deposits is the only way to restore the loss of efficiency, however.
Due to the high risk of glass damage, the manufacturer of reaction devices does not encourage acid cleaning.
The company then learned the neutral pH method.
After careful inspection of reactor jacket conditions and determination of sediment composition, the cleaning process lasted for 72 hours.
The analysis of the waste cleaning solution shows that about 30 pounds (13. 5 kg)
Remove iron corrosion products from the system.
After the container was restored to use, the heat transfer rate increased by more than 30%, and the reaction time increased by more than 30 minutes per batch.
This significant improvement was achieved without the risk of glass damage.
Conclusion space corrosion and Deposition Control of jacket in glass
Lining reactors are often ignored before dirt problems occur, prolonged heating and cooling times, compromising product quality and reducing productivity.
The traditional method of cleaning the reactor housing with acid or alkaline solution is dangerous or ineffective.
A unique, neutral pHcleaning program has proven to be capable of improving
By removing mineral deposits without damaging the glass lining or the base metal of the reactor, the efficiency of the lining reactor is significant.
Recommended products by major glass manufacturers-Lining equipment.
BetzDearborn 4636 samerton Road treworth, PA 19053. Write In 466 -
Or reply online * iron remover for BetzDearborn Ferroquest closed system.