Why is nitrogen (N) so important?₂)? It's very simple: it is used in the most diverse fields of the oil and gas industry to prevent risks of fire and explosions both in installations on land and at sea.

The reason is simple, but its use is not. Nitrogen gasifies the upper free space of oil deposits present in refineries or oil tankers. If oil is extracted from the storage tank, the oil level decreases; likewise, the upper free space of the oil reservoir must be inertized with nitrogen.

Nitrogen is a very inert gas that replaces existing oxygen, so it prevents chemical reactions that can cause ignition. Oil and gas refineries, as well as oil tankers, are provided with an extensive pipeline network. Pipes that are not used are constantly inerted with nitrogen and are inspected using different pressure values; in this way, damage and production losses can be counteracted by anticipating them.

The N₂ upstream, midstream and downstream

The oil and gas industry supply chain is divided into three segments: Upstream, Midstream And Downstream, and nitrogen plays an important role in all of these segments.

1. Upstream

Upstream is the exploration and production phase of crude oil and natural gas. The N₂ can be used for different applications in this segment, one of which is nitrogen injection.

Normally, when hydrocarbons are recovered from a new reservoir, the typically high reservoir pressure ensures that these hydrocarbons flow easily into production wells. Over time, however, reservoir pressure decreases. To increase pressure, oil companies inject nitrogen into the well.

Another possibility is that hydrocarbons become clogged and need to be purged. Nitrogen is the perfect gas to extract these hydrocarbons, since it doesn't mix with oil or water. An injection of nitrogen will improve oil flow and increase hydrocarbon production.

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2. Midstream

Midstream is the processing, storage and transportation of crude oil and natural gas through oil/gas pipelines. Before an oil pipeline can be put into operation, it needs a thorough cleaning. Nitrogen is often used for cleaning by Pigging and the purging of a pipe. After cleaning by Pigging, nitrogen is pushed through the pipe several times until it is completely oxygen-free and has reached the desired dew point. During this process, multiple stops can occur for various reasons (for example: scraper (Pig) stuck in the pipe, valve leak, etc.

3. Downstream

The downstream includes the refining of crude oil into finished products such as gasoline, Fuel-oil and petroleum products. One of the many applications of nitrogen in industry Downstream is the inertization of nitrogen.

Inert gas is used to inertize hydrocarbon storage tanks, ensuring that inert conditions are maintained. The main purpose of this operation is to prevent explosions, discoloration, polymerization and other unwanted changes in quality. The entire process is controlled by the flow rate and pressure of the inert gas stream and/or the oxygen level in the exhaust gases.

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