The petrochemical industry is undoubtedly one of the biggest consumers of steel piping. These pipes transport crude material from oil/gas wells to refineries and are involved in various other processes, including distribution, refining, and transmission. This oil and gas industry consumes many steel products as part of their transport system.
Steel pipes carry crude materials, steam, water, sewage, and finished products. It has major applications in petrochemical factories, refineries, oil/gas reserves, steam plants, and other facilities.
Petrochemical pipes are made from steel, alloys, copper, and cast iron, depending on their use. Even plastic and reinforced concrete get sometimes used.
The uses of steel pipes in the petrochemical industry are divided into three main divisions composed of
- Upstream Use
- Midstream Use
- Downstream Use.
Out of the three, midstream and downstream are the two sectors conventionally attached to the petrochemical industry. These two sectors are relevant because they involve the processing and distributing of oil and gas or oil/gas products. Some of the products made during these phases include methanol and halogenated hydrocarbons.
The petrochemical industry requires piping that can withstand high levels of heat and pressure. These pipes also must be corrosion resistant as many substances like ethylene, butenes, and propylene get added as industrial solvents in the manufacture of petrochemical products.
Depending on their role in processing natural gas and petroleum-derived hydrocarbons, piping can get divided into
- Seamless Pipes/Tubes: Meant for use in pipelines
- Steel Tube: Meant for low-temperature use
- Steel Pipe: Meant for high-temperature use
Three Major Stages of the Petrochemical Industry.
These sections get named according to their gas and oil production and supply chain position. For example, the term upstream denotes its place as the first step in oil production, exploration, and extraction. The other two oil production sectors follow suit by being second and third in the supply chain position.
Upstream
As discussed, the upstream sector encompasses the initial steps of oil and gas production. Consequently, one of the essential tasks of this division is exploration. This sector involves a fair amount of research and land profiling because the crude products must first be discovered to get extracted.
Gathering pipes get mostly used in upstream gas and oil, and these piping have diameters of 18 inches. They also typically have a pressure capacity of 715 psi and are about 600 feet long.
Type of Specification Used
The pipes used for transporting liquid hydrocarbons and other liquids are ASME B31.4. This specification covers factors like design, construction, materials, inspection, assembly, and testing of liquids like
- Natural Gasoline
- Natural Gas Liquids
- Liquid Alcohol
- Crude Oil
- Condensate
- Liquid Anhydrous Ammonia,
- Carbon Dioxide
Midstream.
The midstream sector takes over the work after discovering and drilling reserve-rich oilfields. For the product to be marketable, it must first be purified and refined in special facilities, and this section is responsible for the transmission of crude oil and gas to these places. This sector s also responsible for transmitting the purified product from these facilities to storage plants and downstream marketers.
Pipes used in midstream are typically transmission pipes, and they have a higher pressure range than other pipes. With pressure resistance varying from 200 to 1200 psi, these pipes also possess larger diameters up to 42 inches.
Type of Specification Used
Specialized, narrow pipelines play a seminal role in midstream sector transport. These are low-pressure pipes connecting oil wells to refineries. Sometimes they also join up with long-haul pipelines to help carry this product over long distances.
Meanwhile, the pipes plants used for process piping- come under specification ASME B31.3. As a midstream step, process piping refers to converting raw gas and liquids into tangible, commercial products. ASME B31.3 also covers pipes found in semiconductor, textile, cryogenic, chemical, and pharmaceutical plants.
Downstream
The downstream oil and gas sector includes elements of the midstream and vice versa, especially regarding refining crude oil into derivatives. Though this purification can be categorized as a midstream process, it is usually regarded as a downstream sector's responsibility.
Pipelines carry raw oil and gas from oil wells into refineries for purification. Here the crude materials undergo several refining processes, including compression, hydro-heating, hydrotreating, and amine testing. And the end product is the everyday materials we see, like heating oil, gasoline, LPG, natural gas, and more. In addition, the materials extracted during processing are also the basis of products like waxes, lubricants, and sulfur.
Downstream pipes are mostly distribution pipes with pressure resistance that can go up to 200 psi. These pipes have a diameter ranging from 2 to 24 inches.
Type of Specification Used
Pipes used for downstream gas transmission/distribution systems may fall under ASME B31.8. This specification covers the maintenance and operation of the transportation pipeline facilities.
Relevant Pipe Specifications for Petrochemical Uses
ASTM A106- For Seamless Pipes Only
This specification includes seamless carbon steel pipes for high-temperature service. The NPS range under this criteria is NPS ⅛ to NPS 48. It supports Schedules 20 to XXH and wall thickness of more than XXH. Under ASTM A106, the minimum wall thickness cannot exceed 12.5% of the nominal wall thickness.
Chemical Properties
| Element | Grade A | Grade B | Grade C |
| Vanadium (Max %) | 0.08 | 0.08 | 0.08 |
| Molybdenum (Max %) | 0.15 | 0.15 | 0.15 |
| Chrome (Max %) | 0.40 | 0.40 | 0.40 |
| Nickel (Max %) | 0.40 | 0.40 | 0.40 |
| Copper (Max %) | 0.40 | 0.40 | 0.40 |
| Sulfur (Max %) | 0.035 | 0.035 | 0.035 |
| Phosphorous (Max %) | 0.035 | 0.035 | 0.035 |
| Manganese (Max %) | 0.27 to 0.93 | 0.29 to 1.06 | 0.29 to 1.06 |
| Carbon (Max %) | 0.25 | 0.30 | 0.35 |
| Silicon (Max %) | 0.10 | 0.10 | 0.10 |
- The total of Cr, Cu, Mo, Ni, and V shall not exceed 1%
Tensile Properties
| Tensile Strength (Minimum) | Yield Strength (Minimum) | |
| Grade A | 48,000 psi | 30,000 psi |
| Grade B | 60,000 psi | 35,000 psi |
| Grade C | 70,000 psi | 40,000 psi |
- The minimum wall thickness for these high-temperature pipes should not exceed 12.5% under the nominal wall thickness specified.
API 5L Grade B Pipes- For Oil and Gas Pipelines
Other commonly used grades include X42, X52, X60, and X65
Chemical Properties
| Elements | Maximum Content in % |
|---|---|
| Carbon | 0.26% |
| Manganese | 1.20% |
| Sulfur | 0.030% |
| Phosphorous | 0.030% |
| Vanadium | 0.15%, unless specified |
| Niobium | 0.15%, unless specified |
| Titanium | 0.15%, unless specified |
Tensile Properties
| Properties | Minimum % |
| Yield Strength | 35,500 psi |
| Tensile Strength | 60,200 psi |
| Weld Seam Tensile Strength | 60,200 psi |
ASTM A333 Pipes- For Low-Temperature Service
This specification covers seamless and welded carbon and alloy steel pipes. It includes Schedules 10 through 160, as well as STD, XH, as well as XXH. The NPS for this specification is ¼ inch to NPS 42 inches.
Chemical Properties
| Element | Grade 1 | Grade 3 | Grade 6 |
| Nickel | 3.18 to 3.82 | ||
| Sulfur (Max %) | 0.025 | 0.025 | 0.025 |
| Phosphorous (Max %) | 0.035 | 0.035 | 0.035 |
| Manganese | 0.40 to 1.06 | 0.31 to 0.64 | 0.29 to 1.06 |
| Carbon (Max %) | 0.30 | 0.19 | 0.30 |
| Silicon | 0.18 to 0.37 | 0.10 (minimum) |
Tensile Properties
| Tensile Strength (Minimum) | Yield Strength (Minimum) | |
| Grade 1 | 55,000 psi | 30,000 psi |
| Grade 3 | 65,000 psi | 35,000 psi |
| Grade 6 | 60,000 psi | 3,000 psi |
ASTM A53- For Welded and Seamless Pipes
This specification covers seamless/welded/galvanized pipes between Nominal Pipe Size ⅛ to NPS 26. It supports Schedules 10 to 160 and STD, XH, and XXH.
Chemical Properties
| Element | SeamlessGrade A | SeamlessGrade B | Type EERW Grade A | Type EERW Grade B | Type FGrade A |
| Vanadium (Max %) | 0.08 | 0.08 | 0.08 | 0.08 | 0.08 |
| Molybdenum (Max %) | 0.15 | 0.15 | 0.15 | 0.15 | 0.15 |
| Chromium (Max %) | 0.04 | 0.04 | 0.04 | 0.04 | 0.4 |
| Nickel (Max %) | 0.04 | 0.04 | 0.04 | 0.04 | 0.4 |
| Copper (Max %) | 0.04 | 0.04 | 0.04 | 0.04 | 0.4 |
| Sulfur (Max %) | 0.045 | 0.045 | 0.045 | 0.045 | 0.045 |
| Phosphorous (Max %) | 0.5 | 0.5 | 0.5 | 0.5 | 0.5 |
| Manganese (Max %) | 0.95 | 1.2 | 0.95 | 1.2 | 1.2 |
| Carbon (Max %) | 0.25 | 0.30 | 0.25 | 0.30 | 0.3 |
- NOTE: These elements should not make up more than 1% of the steel composition.
Tensile Properties
| Tensile Strength (Minimum) | Yield Strength (Minimum) | ||
| Seamless/ERW Pipes | Grade A | 48,000 psi | 30,000 psi |
| Grade B | 60,000 psi | 35,000 psi | |
| Continuous Welded Pipes | 45,000 psi | 25,000 psi |