A pressure vessel is a closed container designed to accommodate a high pressure gas or liquid fluid that is substantially different from the ambient pressure. Pressure vessels have wide applications in industries such as oil and gas, chemicals, petrochemicals, distillation towers, nuclear reactors, natural gas storage systems, and hot water storage tanks.

Various sizes and shapes of pressure vessels are manufactured for various purposes. In general, the type of shape that is often encountered is a long cylindrical model with two heads. Pressure vessels work at internal pressures that are higher or lower than air pressure. In addition, the operating temperature of these systems is also different.

A simple example of a pressure vessel is a pressure cooker on cooking utensils. Pressure cookers are made of high-pressure, heat-resistant metals such as stainless steel. A pressure cooker works to hold the hot steam pressure in the pan so that the steam pressure does not leak until the cooking ingredients soften completely due to heat pressure. Therefore, the pressure cooker lid is quite difficult to open because it uses a strong magnet so that the pressure does not leak.

Pressure vessels are designed to work to reach the pressure level required for certain applications. Pressure vessels can apply pressure either directly through valves, gauges, or indirectly through heat transfer. Potential pressure levels range from 15 psi to about 150,000 psi, while temperatures are often above 400 °C (750 °F). Pressure vessels can accommodate fluids ranging from 75 liters (20 gallons) to thousands of liters.

The main components of a pressure vessel:

Pressure vessel components. Source: atrinsanat.com
  • Shell: The main component of a pressure vessel to accommodate pressure. The shell is usually cylindrical, conical, or spherical.
  • Head: Head is useful for closing the shell. Heads are generally curved. The reason for the curved shape is that it is more resistant to pressure and allows the head to be light and inexpensive.
  • Nozzle: A cylindrical component that penetrates into the shell or head. Nozzle is used to install inlet and outlet pipes, install measuring instruments (altitude, temperature, pressure).
  • Support: Support is used to support all pressure vessel loads so that they stand firm.

Types of pressure vessels that are often found in industry

  • Process Vessel: these vessels are designed to contain and store liquids only and are used for integrated operations in petrochemical facilities, refineries, gas plants, oil and gas production facilities, and other facilities.
  • Autoclave: These vessels are usually cylindrical in shape because their round shape is better able to withstand high pressure safely. The autoclave is designed to accommodate items that are placed inside and then the lid is tightly closed.
  • High pressure vessels: the most durable vessels on the market capable of operating under the heaviest loads and providing the best resistance to corrosion, temperature and pressure. High-pressure vessels are usually made of stainless steel. These vessels are particularly suitable for use in: high speed mixers, chemical reactors and supercritical extraction systems.
  • Heat Exchanger: a device that transfers heat from one medium to another. Heat exchangers are most commonly used in industrial facilities such as iron and steel, petroleum, petrochemical, gas, power generation, food, pharmaceutical, leather, textile, air conditioning, ships, and marine industries. Learn more about heat exchangers >>click here!
  • Pressurized water tank: In a tank water well system, this tank generates water pressure by using compressed air to force it down above the water. Due to this pressure, water is forced out of the tank through pipes inside your home when the valve is opened.
  • Vacuum tank: The vacuum tank functions to filter air or liquid through suction, outgassing, pumping, or a combination of techniques. These tanks use pressure to prevent contamination, purification and dehydration.
  • Boiler: a closed pressure vessel used to heat a liquid. This heating fluid is used for cooking, power generation, central heating, water heating, and sanitation.

Selection of pressure vessel material

Materials that are often used in the design of pressure vessels are:

  • Carbon steel (with carbon content below 0.25%)
  • Manganese carbon steel (stronger than carbon steel)
  • Low alloy steels
  • High alloy steels
  • Austenitic stainless steel
  • Non-ferrous materials (aluminum, copper, nickel, and alloys)

In the design of pressure vessels, there are standards and codes that govern. The ASME Boiler and Pressure Vessel Code (ASME Code) is a well-known standard for pressure equipment and components worldwide and provides manufacturer certification and quality assurance. ASME sets standards for the design, materials, manufacture, inspection, testing, and operation of boilers and pressure vessels (including electric boilers, heating boilers, nuclear power plant components and transportation tanks). More than 100 countries use ASME standards and codes. The addition of the ASME certification mark to pressure equipment gives more confidence to business partners, users and governments.

Due to the complexity of pressure vessel design, analytical calculations are too complicated or even impossible. One of the most commonly used methods is to use existing standards, but sometimes these standards cannot cover in detail and comprehensively the design of pressure vessels. unique or custom vessel, so that computer modeling methods are used to calculate the structural parameters, or also known as Finite Element Analysis (FEA).

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