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As you know, a pressure vessel is a container engineered to contain gases or liquids at a pressure different from the ambient pressure. These vessels can resist the high internal pressure exerted by its contents, ensuring safety during operation. These Vessels are available in various sizes and different shapes for specific applications.
It is, therefore, essential to know the variety of vessels for application. In this blog, we have discussed types of ships based on application shape and head of the vessel. Keep reading to learn more.
Types of Pressure Vessels
Many pressure vessels are available in the market to suit your requirements. In Broad terms, the pressure vessels can be categorised based on their application, the shape of the vessels and their heads. In this section, we discuss the different types of Process Vessels.
Based on Application
1. Distillation Columns
Distillation columns can separate components in a liquid mixture by heating the mixture to convert it into a vapour state. The vapours are further condensed to get the pure liquid. These columns are typically used to refine crude oil and in chemical production.
2. Boilers
A boiler is a pressure vessel used for steam generation. Steam is used for heating, generating power and other industrial processes. Boilers are commonly used in power plants in various industrial settings. Such process vessels are designed to tolerate high pressures and temperatures to ensure steam is generated efficiently and safely.
3. Heat Exchangers
A Heat exchanger can control temperature by exchanging heat in various processes. It exchanges heat by transferring it between two or more fluids without mixing them up. These vessels have a series of metal tubes. One of the products flows through these tubes while the second product flows around it. In this fashion, the heat is exchanged between the two products.
Such pressure vessels are used explicitly in HVAC systems, refrigeration units, and chemical processing plants.
4. Reactors
A Reactor is a pressure vessel in which chemical reactions are carried out in the pharma and petrochemical industries. Like boilers, reactors are also designed to withstand high temperatures and pressure. Reactos also provide precise control over responses. Such process vessels are typically used in drug, chemical and other product manufacturing. A Reactor can have agitators, baffles, or coils as the internal components.
5. Storage Tanks
A Storage Tank is a process vessel to store liquids or gases at different pressures and temperatures. They are available in various sizes and designs to meet the storage specifications of the substances.
6. Air Receiver Tanks
An Air Receiver Tank is a pressure vessel that stores compressed air. It is commonly required to power pneumatic tools and equipment.
Based on the Shape of the Vessel
The shape and size of a pressure vessel depends on the design requirements, the product to be stored, the space available at the site and the company’s budget. Here are the most common pressure vessel shapes:
1. Cylindrical Pressure Vessels
It is the most common type of vessel, having a cylindrical shell with two end caps. This pressure vessel is used to store liquids and gases under high pressure.
2. Spherical Pressure Vessels
These vessels are spherical shaped and are more expensive to manufacture than cylindrical vessels. However, spherical vessels are preferred over cylindrical vessels where space is limited.
3. Ellipsoidal Pressure Vessels
An Ellipsoidal pressure vessel is curved, similar to a squashed sphere. Besides storage, these vessels are used to transport fluids under high pressure.
4. Torispherical Pressure Vessels
A Torispherical pressure vessel is made of a cylindrical shell with a toroidal or dish-shaped end cap. Owing to their strength, they are the favourite for high-pressure applications.
5. Conical Pressure Vessels
As the name suggests, these pressure vessels are cone-shaped and used to store and transport fluids or gases under high pressure.
Based on their Heads
Every Pressure Vessel requires specialised ASME caps on each end. These caps are referred to as “heads”. In this section, we discuss the most commonly used “heads”:
1. Flat Heads
A Flat head pressure vessel is the simplest of all types. It has a flat plate welded to the end of a cylindrical or spherical shell. The vessel has both ends flat rather than curved. Such process vessels are used where space or structural considerations necessitate a flat head. These are far less common than their curved counterparts as they cannot withstand high pressures and may require thicker material to tolerate high pressure.
2. Ellipsoidal Heads
Ellipsoidal heads have an elliptical-shaped head following a 2:1 ratio- the width is double the depth. These Pressure Vessels are suitable for high-pressure applications as they evenly distribute stress. However, it is less efficient than a hemispherical head while handling high pressures. The thickness must be increased to meet the ASME Specifications.
3. Torispherical Heads
A pressure vessel with torispherical heads has a dish-shaped end cap attached to a cylindrical shell. Since they render better stress distribution, they are commonly used in the chemical and petrochemical industries.
4. Hemispherical Heads
Such pressure vessels have a curved shape head, resembling that of a half sphere. The depth of its head is half the diameter, and the standard thickness of its head is nearly half the thickness of the shell of the pressure vessel. Although it has the thinnest head, the design is more expensive than others because it cannot be fabricated from a single flat sheet and requires welding assembly. These kinds are also valuable for applications requiring even stress distribution.
5. Flanged & Dished Heads
Pressure vessels with Flanged and dished heads (F&D) are used where the vessel’s height is limited and maintained at low pressure. The tight knuckle radius on F&D (flanged and dished) heads necessitates a greater thickness than the vessel’s shell.
Applications of Pressure Vessels
As discussed in the above section, the various types of pressure vessels are available for different functions. In the section below, we discuss the applications in every industry.
1. Oil and Gas
Pressure vessels form the core of the oil and gas industry to store and transport crude products such as crude oil, natural gas, and other petroleum products. The vessels are needed for production, exportation, and refining processes to ascertain their safe handling and storage of flammable hydrocarbons.
2. Chemical Processing
In the chemical industry, pressure vessels are used for various purposes, such as chemical reactions, distillation, and storing chemicals. The vessels are tailored to bear the corrosive chemicals and high temperatures for the efficient manufacturing of the chemicals.
3. Food and Beverage
In the food and beverage industry, Pressure vessels are the containers that carry out critical processes like pasteurisation, sterilisation, and fermentation. Since the pressure vessels can operate at controlled temperature and pressure, the safety and quality of food and beverage products are ensured.
4. Pharmaceutical
Pressure vessels are the reaction vessels for manufacturing drugs, vaccines, and other medical products. The vessels used in the pharma industry must meet stringent regulatory requirements to ensure the safety of the products.
5. Aerospace
The aerospace industry requires pressure vessels to store fuel, gases, and other fluids in aircraft and spacecraft. Such vessels are engineered to tolerate high pressure and temperature during the flight while ensuring the safety and reliability of the aerospace vehicles.
Conclusion
To conclude the blog, the ASME Boiler and Pressure Vessel Code is the golden standard for pressure vessel manufacturing excellence. Check Sections II, V, VIII, and IX to refer to the guidelines for construction materials, design, engineering, and welding standards. The other references, such as EN 13445, API 510, and AD Merkblätter, can help you gain critical insights regarding construction, piping, inspection, design, repair, and maintenance protocols for pressure vessels.
When investing in pressure vessels, safety and efficacy are paramount and cannot be compromised at any cost. If you have any further questions, please reach us at TSA.
FAQs
A: Pressure Vessels are often designed in spherical shape because when designed in spherical shape, they can distribute heat evenly, thus ensuring the efficiency of the process.
A: Pressure vessels are engineered to withstand high temperatures and pressures. Using a pressure vessel that meets the regulatory specifications helps ensure the process’s efficiency while not risking the safety of the personnel, the equipment and the environment.
A: Pressure Vessels are used in the Oil and Gas, Chemical manufacturing and Processing, Food and Beverage, Pharmaceutical, and Aerospace industries.
