Question

For the case " Insulated process plant piping (carbonsteel) " define in details the material aspect and environment aspect. Environment is not limited to chemistry but also to process parameters.

Subject = Materials Integrity and Corrosion

Answer 1

Solution

Insulated process insulation pipings play a very core role in various industrial processes in industries such as petrochemicals, boilers at powerplants, food processing industries, etc. The industrial insulated pipings are very crucial for the efficient and safe operation of various equipment and processes as poor piping arrangements can lead to various economic losses including industrial accidents with loss of lives and property.

The key function of insulted industrial pipings is to offer a connected pathway between various process stages and equipment, at the same time this pathway must offer safety and to prevent loss of energy from the overall system.At the industrial scale, consistent product output is the main purpose and various system physical properties of matter flowing or transported through these pipelines must have maintained specific temperature, pressure, density, viscosity, etc.

The function of insulated piping systems at industrial scale -

• To prevent energy losses.
• To maintain process constraints such as temperature, pressure, etc.
• Provide support to withstand the operational environment.
• To achieve durability and reliability such as to avoid oxidation of pipeline
• Avoid undesirable condensation
• Avoid leakages of gases
• Antifrost factors
• Human protection from high-temperature exposures

Various types of insulations and application conditions

There are various types of piping insulations are available as per the application and operating environment conditions. the key factor to decide is the operating temperature, as per the law of thermodynamics heat flows from hot place to cooler one so a hot pipe or cool pipeline has a tendency to lose or gain heat from the surrounding

To avoid this heat exchange proper insulation is necessary and there is the various industrial standard which decides the type of insulation to be used, for example, a food processing industry will use different insulation compared to a powerplant one.

Various operating temperatures of insulated pipings

Industry	Operating Temperature
Foundry or refractory industry	+1300 oF
Refrigeration units	-49 oF - (+)75 oF
Cryogenic applications such as space industry	-50 oF
Food Processing applications	+14 oF - 600 oF

_{^{Temperature data is from online sources}}

Types of insulations

Insulation Type	Material
Fibrous Insulation	Inorganic fibers with binding agents are used, most used fibers are glass wool,alumina-silica fibers,slag wool, etc.
Cellular Insulation	Glass, Rubber, Plastic, foam base materials
Flake Insulation	Made from a flake of materials such as vermiculite
Reflective Insulation	Reflective jackets with a coated mirror-like material such as silver to avoid radiant heat transfer and also convective heat losses.
Granular Insulation	Made from special fine fragments that contain hollow void passages thus allow the flow gases, examples are molded pearlite and calcium silicate.

Every type of insulation has its own value of thermal resistance that will determine the thermal efficiency of that insulation.

The thermal resistance of insulation layer determined by the given formula -

Where -

• D_x diameter at desired location of calculation ,it can be D_e or D_i depending upon case
• D_e outer diameter
• D_i inner diameter
• is the thermal conductivity of the insulation material

Selection of piping material

The operating process physical parameters will directly decide the type of material to be used, as various operations operational conditions present different design challenges. Industries use pipings for various applications and operating conditions some will require high temperature, high pressure, high oxidation resistance, etc.

The most common material used for industrial applications is steel and steel alloys, as its strong durable, can easily withstand high temperature and pressure conditions also have high oxidative corrosion resistance.

Materials	Adavantages	Applications
Copper	High thermal conductivity, high oxidation resistance	Heat exchangers in AC, cooling systems, water purifiers.
Stainless steel	High durability, high corrosion resistance	Domestic water supply
Iron	Highly ductile and durable	Main water networks
Polyvinylchloride	High corrosion resistance, low cost	Household piping, industrial application for low temperature environment