ALL YOU NEED TO KNOW ABOUT SHELL AND TUBE HEAT EXCHANGER

A shell and tube heat exchanger is used in high-pressure applications where the temperature of the fluid is regulated using a shell and tube system through which the fluid flows. Exchangers are used for both heating and cooling processes, but largely they are used for cooling processes. They are mostly used in oil refineries and chemical industries. 

From the name, one can understand that these exchangers are used for transferring heat from one fluid to another. These exchangers consist of a shell that is a large pressure vessel with a bundle of tubes present inside it. One fluid runs through the tube and the other fluid runs through the shell and during this process the heat flows from hotter fluid to cooler fluid due to which the temperature of the hotter fluid comes down. 

A Shell and tube heat exchanger is necessary for cooling certain fluids in the industries to avoid accidents due to overheating. In many industries, fluid can only be heated up to a certain degree for a certain function after which the temperature must be controlled to ensure a controlled and effective production process. Heat exchangers are required to keep water, gas, oil and chemicals within a safe temperature range. Heat exchangers can also be used to detain steam or heat exhaust that is released as a by-product and use further in the manufacturing process. This increases the efficiency of operation and cost-effectiveness as a whole.

There are different parts associated with a shell and tube heat exchanger such as heat transfer tubes, heat exchanger fans, condensers, belts, coolants, tubes and lines. All these systems present inside the shell and tube heat exchanger increase the functional efficiency of the heat exchanger and improves the flow of the fluid inside it. 

DIFFERENT TYPES OF WATER FOR PHAMACEUTICAL USE

Water is one of the most important ingredients that is used in the pharmaceutical industry. It is used both as a solvent for processing and as an ingredient for the formulation of pharmaceutical products in the pharma industry. The water used in pharmaceuticals is different from regular water or what we call tap water. Producing water for pharmaceutical use is a complex task in which water has to go through various stages such as production, storage and distribution.  

Generally, water has to be purified before using for pharmaceutical applications and sometimes has to go through advanced purification processes to get rid of microbial contamination. 

Let us take a quick look at the different grades of water that are used for pharmaceutical applications.

Drinking water or regular tap water that comes from the public supply is processed and converted to purified water before using the water for pharmaceutical use. The sources of drinking water are lakes, ponds, rivers, seas, springs and wells. The water obtained directly from these sources is not fit for pharmaceutical use. It has to go through a purification process that is done with the help of water treatment systems where demineralization, softening and particle reduction methods are applied to the water to make it fit for further processing.

Purified water is another class of water used in pharmaceuticals. To obtain purified water, the water has to go through electrode ionization and reverse osmosis purification systems. 

Highly purified water is another grade of water that is used in pharmaceuticals and is considered to be one of the purest forms of water besides water for injection. Highly purified water is free of endotoxins and pathogens and also prevents recontamination of the water from the microbial organisms. 

Water for injection is the highest or the purest form the pharmaceutical water as compared to any other form. It is manufactured from purified water using a Multi-column distillation process or vapor compression.

TYPES OF WATER USED IN PHARMACEUTICAL WATER SYSTEM

Water is one of the key ingredients that is used in a pharmaceutical water system and pharmaceutical engineering. Water is both used as a solvent for processing and as an ingredient for the formulation of pharmaceutical products. These pharmaceutical products are consumed by human beings and thus the water used for processing these products must match with the given industrial standards. 

Pure water is used for the formulation and processing of pharmaceutical products. To convert the normal water to the purest form, the water has to go through the purification process. There are different types of purification systems used in pharma industries such as distillation, reverse osmosis, filtration and ion exchange. Microbial contamination is another problem that is often faced during pharma manufacturing and proper cleaning methods have to be ensured to get rid of microbial contamination.

Let us discuss in detail the types of water that are used in the pharmaceutical industries.

Different grades of water are required in a pharmaceutical water system such as water for injection, drinking water, purified water and highly purified water. The type of water used depends on the pharmaceutical application and the nature of the pharmaceutical product. 

Drinking water generally comes from the public water supply. Water is extracted from different sources such as sea, lakes, wells and springs and later passed through water treatment systems such as desalinization, softening, particle reduction, etc. Purified water in the pharmaceutical industry is obtained from drinking water. The drinking water of portable water is passed through various types of purification systems such as electrode ionization, reverse osmosis and filtration. Highly purified water is standardized as per European standards, is free of pathogens, and prevents microbial recontamination. Water for injection is the cleanest form of water that is used in the pharmaceutical water system. It is producing using Multi-column decontamination process or vapor compression.

Importance of CIP System

Day by day, the CIP Systems are becoming more complex and popular, particularly in the pharmaceutical and food processing industries. The CIP System design makes the cleaning process of the interiors easy by providing effective and efficient cleaning without the requirement of major disassembly. Also, CIP systems allow thorough cleaning with minimal exposure to harmful chemicals and with minimal contamination of food and beverage items.

In food and beverage applications, there are chances of contamination due to the presence of leftover food items in the interior parts of the machinery. CIP systems are the best cleaning option as the interiors are cleaned as per the guidelines and cleaning standards, unlike conventional cleaning methods. The CIP structure is made up of stainless steel or other non-corrosive material and cleaned regularly to avoid contamination from rust and bacteria. 

In the case of industrial wastewater systems, the water coming from the laboratories and other industrial locations, which has been acted upon by various harmful chemicals, can be harmful to sewage systems and wastewater treatment plans. Usage of bleach can kill the bacteria but to remove the process chemicals, it is important to pass the water through chemical processes.

Chemicals used in a CIP System cleaning process are used to remove the chemicals from the wastewater before passing the water to the treatment plant or sewage plant. These cleaning agents or chemicals are one of the most essential parts of the CIP process. A detergent is generally used to run through the lines. Detergents and caustic soda are highly corrosive in nature and so a stainless steel non-corrosive structure is essential to avoid leakage. 

Fittings and accessories that are used for CIP must be made up of PVC, stainless steel or Teflon, especially the gaskets and fittings.

Brief about CIP System

CIP system, also known as Clean in Place systems is a process in which interior surfaces of piping, fittings, vessels and other important equipment are cleaned without any major disassembly. In the food and beverage industries, automated CIP systems are used for cleaning the product transfer lines, homogenizers, blenders, filters and processing tanks.

On the other hand, the clean out of place or COP method is used to clean the machine parts that need dismantling. Clean out of place is used for cleaning the machine parts such as washers, cabinets, hoses, clamps, buckets, fittings etc. 

To clean the entire machinery effectively, work has to be done on the factors such as time, action, chemical composition and temperature. The CIP system must be designed considering these factors so that the cleaning takes place effectively and as per the validation requirements. 

In food and beverage processes, the liquid soluble product is often easy to clean from the parts, but there are variations when liquid composition changes. For example, tomato ketchup and orange juice are difficult to clean as compared to a sports drink. Precaution must be taken during the cleaning of dairy products as there are chances of bacterial growth that may lead to the contamination of the products. In the case of solids, the CIP system’s design varies as per the material’s shape, size, load and surface adherence. To clean an ice cream, it may take more time for the solution to get at the right temperature. Also, extra cleaning materials like caustic soda and other chemicals are required to clean the dairy proteins and fats. 

There are specific parameters that should be taken into consideration for making a near-perfect CIP System design like process line size, the distance of the process from the desired location, tank size, pump size etc.

Brief on Water filtration process

Water filtration process is a method in which particles are removed from water using mechanisms such as flocculation, straining, surface capture and sedimentation. In straining method, strainers are used which consist of a thin physical barrier film that is usually made up of steel or plastic. Strainers are generally used to filter out large objects such as fish and leaves from the water. There is another type of strainer known as micro strainer that is mostly used to filter out fine particles out of water such as algae and silt.

Filters, as commonly known in a water filtration process generally consists of a system through which most of the particles in the water are captured.

There are different types of filters used in water filtration processes. One such filter used in filtration is known as slow sand filter. Slow sand filter consists of a bed of sand that is situated within a filter shell. The impurities are captured on the surface of the sand surface forming a debris and the water is filtered out from the bottom.

Activated carbon filters are another type of filtration filter which can be used to remove chlorine and organic compounds from water supplies. The technique or method used in this filtration process is known as chemical adsorption. These carbon filters have to be activated before they are used for water filtration.

Another way to filter the water is through chlorination and de-chlorination. In chlorination, chlorine is added to the water to kill bacteria, viruses and other unwanted microbial organisms. The temperature and pH level of water affects the effectiveness of chlorination. Although chlorination kills bacteria and microbial organisms, it can react with other components of water and create unwanted compounds.

The feed water is filtered before passing it for further industrial processing.

Brief on Shell and tube heat exchanger

A Shell and Tube heat exchanger is used to transfer heat between fluids. These exchangers consist of a large pressure vessel that surrounds a bundle of tubes present inside it. They are used for heating and cooling processes which are carried out in plants and refineries. In plants and refineries, different types of machinery and substances are heated to a particular temperature and the heating process is monitored so that the machinery doesn’t get overheated. Shell and Tube exchanger can come to the aid in such situations by helping the machinery to cool down by exchanging the heat from it.

They are also used for air conditioning, in cooling and heating systems. In some factories and industries, Shell and Tube Heat exchangers are used for keeping machinery, water, gas and chemicals within a safe temperature range. These exchangers can also be used to capture heat from steam or by-products generated from a process and use this steam or by-product for other different processes saving the manufacturing cost.

In a typical Shell and Tube heat exchanger, different fluids of different temperatures are present. One of the fluid flows through the shell and the other fluid flows through the tubes present inside the shell. The heat from the hotter fluid is transferred to the fluid with a comparatively cooler temperature through the tube walls. To increase the efficiency of the exchanger a larger heat transfer area should be selected and the number of tubes should be more. Other equipment such as fans, condensers, coolants, belts and additional tubes increases the efficiency of the tube heat exchangers.

There are different types of Shell and Tube Heat Exchangers and they can be classified into different types such as direct contact heat exchangers, indirect contact heat exchangers and many more.