The rubber used to make petrochemicals tank lining is:

Buna-N

The correct answer is option 4. Buna-N.

Buna-N, also known as Nitrile rubber, is a synthetic rubber copolymer made from acrylonitrile (ACN) and butadiene. The ratio of acrylonitrile in the polymer can vary, which influences its resistance to oils and other chemicals.

Key Properties of Buna-N:

Oil and Chemical Resistance: One of the most important properties of Buna-N is its excellent resistance to oils, fuels, and petrochemicals. This resistance comes from the polar nature of the acrylonitrile component, which makes it less permeable to non-polar substances like oils.

Temperature Resistance: Buna-N can withstand a wide range of temperatures, typically from \(-40^\circ C\) to \(108^\circ C\) (\(-40^\circ F\) to \(226^\circ F\)). This makes it suitable for environments where the tank contents may be stored at elevated temperatures.

Mechanical Strength: Buna-N exhibits good tensile strength, abrasion resistance, and flexibility. These mechanical properties ensure that the lining is durable and can withstand physical stress without cracking or deteriorating.

Resistance to Degradation: In addition to its chemical resistance, Buna-N is also resistant to degradation from environmental factors like ozone and sunlight, which can be particularly beneficial for tanks that are exposed to the elements.

Application in Petrochemical Tank Linings: Buna-N's combination of oil and chemical resistance, mechanical strength, and durability** makes it an ideal choice for lining tanks that store various petrochemical products. The lining protects the tank from the corrosive effects of the stored chemicals, ensuring the tank's integrity and longevity.

Additionally, Buna-N is relatively cost-effective compared to some other high-performance elastomers, making it an economically viable option for large-scale industrial applications like petrochemical storage.

Comparison with Other Rubbers:

Neoprene: While Neoprene also has good chemical resistance, it is more commonly used in applications involving exposure to moderate chemicals, weathering, and ozone. It's not as specifically resistant to oils and petrochemicals as Buna-N.

Vulcanized Rubber: This refers to natural rubber that has been chemically treated to improve its properties, but it lacks the high level of oil and chemical resistance that Buna-N offers.

Buna-S (SBR - Styrene-Butadiene Rubber): This is more commonly used for tire manufacturing and other applications where oil resistance is not as critical. It's less resistant to oils and chemicals compared to Buna-N.

Conclusion:

Given its superior oil and chemical resistance, along with its durability, Buna-N is the preferred choice for petrochemical tank linings. Its ability to resist the aggressive chemicals found in petrochemical products ensures that the lining will protect the tank and prevent leaks or contamination, making it the go-to material for this application.

Thus, the correct answer is option 4. Buna-N.