Muhammad Asim NiaziJanuary 27, 2022
Tag: Glass-Lined Vessel , pharmaceutical
Glass-Lined Vessel is a specialized vessel with a gloss coating on its inside surface. The glass surface prevents the vessel’s surface from chemically reacting with the solution inside. Over time, the surface reacts with pharma products inside a vessel. The reaction of the vessel’s surface with the pharma product is attributed to many problems such as rust and corrosion. Common vessels used in pharma manufacturing are made up of Stainless Steel that is considered safe for pharma products.
Like ordinary vessels, different physical variables, such as Temperature and Pressure, can also be controlled to achieve favorable process conditions. Additionally, they are constructed in different capacities to cater requirements of different pharmaceutical manufacturers.
The solution used in the glass-lined vessels is pure chemicals. These chemicals have a strong tendency to react with the material. In pharmaceuticals, these are called Active Pharmaceutical Ingredients (API) or Active, which form the basis of drug manufacturing. Without Active, pharmaceutical product is just a mixture of different components without any therapeutic effects.
There are various types of vessels used in a pharmaceutical manufacturing environment. The function and application of a department define the vessel selection criteria of Glass lining equipment. For example, in the water treatment plant, the vessels store incoming raw water or to store purified water. This application vessel without any specialized glass lining can be effectively used to carry out the process operation. Using glass-lined vessels in these types of applications is a waste of resources. Similarly, in pharma manufacturing, some departments actively use as their basic ingredient such as injectable department, where the ordinary vessel is not feasible, and only glass-lined vessels can be used.
In addition to pharmaceuticals, glass-lined vessels are also used in industries that use the chemically active substance in their process operation. Examples include Petrochemicals, foods, and pesticides.
The glass-Lined vessel market is one of the stable markets in the pharmaceutical sector, and its trends are showing steady growth. In 2019 the global glass-lined market was worth USD 593.5 million. In 2026, It is expected that the global market will reach USD 796.8 million at a CAGR of 5.2%.
Major markets for glass-lined vessel Manufacturing include North America, Europe, Asia Pacific, and the MEA. Mostly, the Manufacturing activity is reported in the Asia Pacific region, with China on top of the list.
The growth is worth noting with respect to the post-pandemic impact. Demand in the pharma sector’s products had remained consistent during the pandemic compared to other industries. However, supply chains, workers, and other raw materials shortages caused a decrease in the production outputs of most pharmaceutical companies.
The growth in the glass-lined vessel industry is also fueled by increased research and development in pharmaceutical drugs, especially in the manufacturing of anti-COVID medicines. Another major factor is advancement in worldwide Vaccine research, development, and production. All of the industries mentioned above use chemically Active Pharmaceutical Ingredients. API manufacturing, storing, packing, and distribution require specialized equipment and production methods, including the Glass-Lined Vessel.
As mentioned above, glass-lined vessels are like ordinary vessels, with a glass coating on the inside of the vessel. The use of glass-coating makes the ordinary vessel expensive. It also requires special care and maintenance for its optimum working and performance.
A glass-lined vessel's advantages are incomparable and cannot be achieved with other vessel types. Some advantages that glass-lined vessels offer include the following.
Glass is a chemically inert substance that shows greater resistance in reacting with other chemicals. Its resistance can be shown in almost every chemical, such as Organic, Inorganics, Acidic, and Alkali substances. The resistance characteristics are not affected by any physical phenomenon, such as temperature and pressure. It continues to remain inert throughout its life period.
Stainless Steel (SS) also has anti-corrosion characteristics, and it is commonly used to make manufacturing equipment for pharmaceuticals. However, the SS material deteriorates due to different operating conditions with time. The deterioration affects the material and results in losing the benefits of SS. On the other hand, the glass is not affected by any of the operating, environmental, and production conditions. The environment also has a negative impact on Stainless Steel and makes pharma products vulnerable to become dangerous.
Regulatory bodies for the pharmaceutical industry have very stringent rules and regulations regarding cleaning. During the inspection, regulatory bodies specifically inspect the company's approach towards cleaning, cleaning procedures, practices, and effectiveness. A general rule of thumb is that cleaning is always required every time a product batch has been finished manufacturing and before starting a new batch.
Glass has a high degree of surface smoothness compared to other materials such as Stainless Steel. Its surface smoothness allows easy cleaning without specialized cleaning agents or equipment.
Simple cleaning methods prevent the vessel surface from rusting and degrading, resulting in extended life of the material. The smooth surface also prevents the sticking of material or compound on the glass surface, contaminating the product being used in the vessel.
Impurities in pharmaceutical products are a common concern for the most pharma product manufacturer. Most pharmaceutical manufacturers use special techniques to prevent the impurities from going into the product, such as using a filtration system.
The ease of cleaning that a glass-lined vessel offer prevents impurities inside the vessel. This helps in controlling impurities concentration level into the product. It also helps prevent the substance of one product type from being mixed with another product. Cleaning also prevents any foreign body from contaminating the product.
The glass is the option that provides an anti-corrosion feature, but there are many other options available. However, the glass is the cheapest option than other commonly available options such as titanium and zirconium. The glass also provides the same degree of protection against contamination, corrosion, and rust obtained with other expensive materials.
Additionally, the glass lining procedure is also cost-effective compared to other materials. Another material requires costly specialized equipment and processes to shape into the vessel. At the same time, the glass lining procedure does not require equipment or processes.
Another reason for cost-effectiveness is the extended life of an application in the pharmaceutical industry. The glass-lined vessel's internal lining increases the vessel's life span compared to another stainless steel vessel. SS vessels, with time, become corrode and degrade by interacting with different materials and substances.
A glass-lined vessel consists of many parts designed to perform their specific functions. These parts are individually manufactured and then assembled in a single vessel during manufacturing. The working of all these parts contributes to a satisfactory glass-lined vessel operation.
Some parts are manufactured to perform a supporting role in the vessel's design, such as the top and lower dome. At the same time, others are manufactured specially to perform a specific function, such as the sampling port.
Some common parts of the glass-lined vessel include the following
The main body is the major part of the glass-lined vessel and consists of a long cylindrical shape body. The main body is thermally insulated with a suitable material. The vessel jacket surrounds the inner cylinder and is commonly used to prevent thermal stress. Thermal stress is one of many reasons that degrades and reduces the vessel's life.
The main body also includes connecting ports for different process measuring variables such as temperature and pressure. Upper and Lower domes are attached to the main body to give the vessel its desired shape.
The upper dome is a round fabricated piece that has a circular base. It connects with the vessel at the upper side of the main body to complete the vessel's shape. The upper dome is where most of the vessel accessories are attached. It also houses the motor and associated gearbox, coupling for the agitator shaft. A manhole is also included to put different materials inside the vessel for product manufacturing. It is also used by personnel to perform cleaning and maintenance activities.
Common accessories that the upper dome consists of include pressure and temperature mounting, sight glass, and different ports.
The lower dome is also a fabricated piece with a circular base like the upper dome. It connects with the main body at the lower end to complete the vessel design from the lower side. The lower dome is usually used to connect accessories to flush or empty the vessel.
Preventive Maintenance of glass-lined vessels
Glass-lined vessels are an excellent choice for manufacturing critical pharma products such as API due to the unmatched features it provides. Additionally, it is a cost-effective solution compared to other stainless steel-type vessels. All of these benefits are due to the glass material used in the vessel's construction.
Regular preventive Maintenance also keeps the glass-lined vessel in optimum working condition, with an extended life span. However, the glass layer requires special care and handling during operation. If not properly used, glass degrades, and the vessels become useless. Preventive Maintenance is also a requirement of different standardization and regulatory bodies such as the International Organization for Standardization.
Before executing preventive Maintenance, a preventive maintenance plan is developed. The plan includes detail of each glass-lined vessel in the manufacturing facility and the frequency of Maintenance mentioned against each vessel.
The frequency of the Maintenance is set according to the manufacturers' recommendations. The usage frequency also determines the maintenance frequency. If the vessel is frequently used, the maintenance frequency is high. If the vessel is not used frequently, the frequency can be below. The frequency can be weekly, biweekly, monthly, bimonthly, quarterly, or yearly.
After preventive maintenance plan is developed, it is reviewed by concerned departmental heads which includes Production, Engineering, and Quality department. After reviewing, the plan is approved, and signed. Control copies are distributed in all the relevant departments, with the original copy kept in document controller or Quality department.
A checklist of preventive Maintenance is necessary to execute the Maintenance successfully. It includes detail of maintenance procedures for all vessel components. The checklist aims to ensure that the maintenance personnel does not overlook any critical parts.
The maintenance personnel completes all the checks one by one and subsequently records the status. After the checklists are completed, the maintenance personnel signs all the documents with the date and records any observations in them. The checklist documents are then forwarded to the departmental head for relevant approvals.
Checklist must be prepared by expert personnel so that not a single aspect of vessel is left un-checked. Commonly, the checklist is prepared by maintenance department, since they have experience in vessel maintenance. Manufacturer also give their recommendation for creating preventive checklist.
Let's look at some important and relevant preventive procedures for a glass-lined vessel.
Physical Appearance: It includes inspecting a glass-lined vessel physically for any damage, chip, or hole. If left unattended, it can cause the vessel's surface to degrade and damage the entire vessel. Sight glass is also inspected to ensure the glass is free from any damage and scratches so that it does not leak the vessel pressure. And prevents any impurities from going inside the product.
Internal Inspection: The vessel is also inspected from the inside to check the surface condition. The glass lining is thoroughly inspected for any damage. Different components such as the agitator, shaft, and baffles are also checked to ensure they are in working condition.
Connections, Seals, and covers: The connection of the attached accessories must be tight without any leakages. Seals must also be present to prevent leaks from both sides. The connection port size must be adequate with respect to the attached instrument or component. Seals must be according to size, adequate material, and free from any physical damage. The main cover of the vessel opening should be damage-free, fixed at its base, without any loosing.
Motor: The motor is the most important part of the glass-lined vessel, and its operation depends on it. The motor rotates the agitator inside the vessel to mix the solution. The motor is inspected for loose bearing, unusual sound, speed control performance, and any significant rise in motor body temperature. Additional motor checks include connection box inspection voltage and current readings through appropriate multi-meter.
Like all process equipment, glass-lined vessels require the test to rate their performance in achieving quality goals. These goals are necessary for a quality pharma product. These tests are performed initially before taking the vessel for production purposes. During validation activities, performance tests are also required to test and verify the vessel's performance against the desired acceptance criteria.
Some performance tests directly related to glass-lined vessels include the following.
A mechanical inspection is performed to inspect glass-lined vessels from mechanical shocks. The vessel is physically inspected for any damage, leaks, metallic degradation, and damages seen and observed through a measurement tool.
Mechanical shock occurs when heavy objects fall or strike the vessel. This deforms the vessel's external shape, for example, a large bump in the outer surface. The deformation weakens the metallic structure and decreases the strength of the vessel. Mechanical shock inside the vessel can also damage the glass lining.
Mechanical shock can also be caused by personnel entering the vessel for maintenance work. It can result from a personnel movement or a worker's tool strike. To prevent internal damage, the personnel should use pads to decrease the impact of personnel movement inside the vessel.
Spark testing is a method to check the glass lining of the glass-lined vessel. In this test, the inspector brushes the vessel surface with the detector. The testing instrument generates a spark if it detects a defect in the glass lining. The location of the defect is identified and marked for maintenance activity.
The spark testing instrument consists of a handheld brush. The brush comprises conductive strings or wires and connects to the detector. The detector can use AC and Dc sources, which generate around 5kV of electrical energy. DC type is the most preferred source because it can easily be grounded with the vessel structure. The AC type is commonly used for encapsulated parts such as blades, which cannot be easily grounded.
Glass-lined vessels have poor thermal shock characteristics. Thermal shock occurs when the vessel is heated or cooled too quickly. A sudden, huge change in temperature causes the glass to be deformed, and as a result glass surface is damaged.
Glass-lined vessels are manufactured by applying a layer of glass on the surface of the steel. Both steel and glass behave differently for the same temperature values. As a result, a sudden change in temperature causes the glass to fracture off the steel surface, exposing the steel surface.
Although glass-lined vessels are excellent resistant to chemical corrosions and their harmful effects, total prevention of glass is not possible. However, compared to other materials, glass has a slow effect of chemical hazardousness.
Chemical erodes the surface of the glass through the effect of abrasiveness. It makes the surface rough, and the glass surface becomes weak with time. The rough surface increases the chances of chemical reaction and results in chemical corrosion. Both factors damage the glass surface and can permanently damage the glass lining.
Continue to read: Handling Glass-Lined Vessel Problems
Muhammad Asim Niazi has a vast experience of about 11 years in a Pharmaceutical company. During his tenure he worked in their different departments and had been part of many initiatives within the company. He now uses his experience and skill to write interested content for audiences at PharmaSources.com.
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