2205 duplex stainless steel gas pipeline: a lasting solution for West to East Gas Transmission

Deep in Xinjiang’s Tarim Basin, natural gas is mined, refined and transported across the country through gas pipelines.However, due to the corrosion of the pipeline, gas leakage occurs frequently.A new natural gas pipeline made of 2205 dual phase stainless steel containing molybdenum is expected to reduce natural gas leakage and protect resources while avoiding environmental disasters.4500 tons is the largest single order for duplex stainless steel in China so far.

What is natural gas?

Natural gas refers to all natural gas existing in nature, including gases formed by various natural processes in the atmosphere, hydrosphere and lithosphere (including oilfield gas, gas field gas, mud volcano gas, coal bed methane and biogenic gas, etc.).

“Natural gas” is defined in a narrow sense from an energy perspective as a mixture of hydrocarbon and non-hydrocarbon gases naturally present in the formation.In petroleum geology, it usually refers to oil and gas fields.It consists mainly of hydrocarbons and contains non-hydrocarbon gases.

Some of the earliest uses of natural gas date back to 500 BC, when the Chinese used hollow bamboo poles to deliver it to stoves and then boiled seawater to make salt.Today, China is trying to reduce carbon emissions and wean itself off coal, so its natural gas industry continues to grow.The Tarim Basin is one of China’s largest natural gas reserves, with more than 200 trillion cubic feet estimated underground.

API 5L PSL2 X65 seamless steel pipes

API 5L PSL2 X65 seamless steel pipes

Drilling for natural gas in the vast Gobi desert

The Tarim Basin is located in China’s westernmost province and is sparsely populated.In the vast Gobi desert and inhospitable desert, the production and transportation of natural gas is a feat.Due to the strong winds, sand, no roads, and poor working conditions, drilling, and especially piping, is extremely difficult, time-consuming, and expensive.

Natural gas is transported from oil and gas wells to nearby refineries for processing.The balance between gas inputs and refinery capacity is critical to maximizing production efficiency.As a result, construction has begun on a new pipeline to connect the two refineries.Upon completion, the refinery will be able to direct the inflow of natural gas to optimize capacity utilization.

Finally, refined natural gas from the Tarim Basin enters the west-East gas pipeline and is transported to all parts of the country for use.

The new pipeline is located in the orange region of the Tarim Basin in Xinjiang, China.

Prevent gas leakage

Environmental conditions in the Tarim Basin bring many challenges to pipeline operation.The vast Taklamakan desert has a dry climate.It’s hot in summer and cold in winter.Strong winds often form huge sandstorms, making working conditions extremely harsh.The soil in this area is highly corrosive and contains a great deal of soluble salt, which is left over from years of evaporation.In addition, natural gas is high in carbon dioxide and contains up to 10% chloride, which also increases its corrosion.In such cases, only materials with high corrosion resistance can provide a permanent solution.

Pipelines carrying highly corrosive crude oil and natural gas are usually made of composite steel tubes lined with a thin layer of 316 stainless steel.The pipes are resistant to corrosive gases and the initial cost is less than that of the whole stainless steel pipe.However, it is much more difficult to weld composite steel tubes in the field than in a factory-controlled environment.The inner stainless steel weld will be diluted by carbon steel, reducing its corrosion resistance.It is found that the weld corrosion of composite pipeline is one of the causes of frequent natural gas leakage in Tarim Basin.

The consequences of a gas leak are environmental damage, lost revenue and, in the worst case, an explosion that must be repaired as soon as possible.However, finding and repairing leaks in this remote desert is a difficult, time-consuming and even dangerous task.As a result, gas companies are seeking more durable pipeline materials for new pipelines to prevent leaks in the first place.

Durable solutions

Life cycle cost method (LLC) is more and more widely used in China.Material selection is based not only on the initial installation cost, but also on the cumulative cost of future maintenance and operation.Over time, duplex stainless steel piping can recoup its costs by avoiding natural gas losses and reducing maintenance and replacement costs.

The “pipeline dragon” in Xinjiang not only optimizes natural gas production in the western region, but also becomes a pioneer in realizing sustainable energy utilization.The investment in the 2205 duplex stainless steel pipeline marks a shift from low cost to a more sustainable and durable solution.