Nitrogen Services (General)
Nitrogen gas is one of the primary products in the oil and gas industry, from the initial drilling of the well to the delivery of the finished product via pipeline, truck, and train to the user. As a naturally occurring gas, nitrogen can safely be used for multitude of services in the energy industry. It has properties that make it an ideal tool: it is inert, nonreactive, nontoxic, and noncorrosive.
Nitrogen services are various: nitrogen can be shipped as a cryogenic liquid, compressed as a dry gas, or filtered from the atmosphere on site using a nitrogen membrane unit. Most commonly, it is delivered in bulk as a cryogenic liquid, then converted to a warm gas using a diesel-fired heat exchanger or non-fired flameless nitrogen pumping unit. It can be delivered at temperatures ranging from -150 to +400˚C and at pressures from atmospheric to 10,000 psi. Recent developments also allow for the use of nitrogen filtering membranes as a method of gas delivery for special projects, including low-rate delivery, underbalanced drilling, and deliveries to remote locations.
Nitrogen Properties (N2 Properties): |
|
| Density (Gas) = | 1.251 g/L |
| Density (Liquid) = | 808 Kg/M3 |
| Boiling Point = | -195.73˚C |
| Dew-point = | -80˚C |
| Chemically inert | Extremely stable element |
Application method depends on the project size and scale, with economics and supply demands being a major consideration. Nitrogen applications can range in size from a two-hour operation involving one pumper and operator to projects lasting months with numerous pumpers and transports. Some projects require very large volumes of nitrogen delivered in a short time period, which is normally provided by the conventional fired pumping equipment. A continuous supply of liquid nitrogen can be delivered to site by specially designed nitrogen transports.
Applications within the energy industry for nitrogen services include:
Nitrogen purging and displacement (LEL and oxygen freeing)
Nitrogen purging services are essential when the required nitrogen supply exceeds a plant’s ability to maintain the high flow rate often required during shutdowns and other maintenance procedures. Nitrogen purging is highly effective for pipeline purges, product displacement, and process pipeline inerting. Our engineers can develop the most effective and efficient purging techniques for any plant or pipeline environment.
FourQuest Energy can design custom procedures for the removal of unwanted atmospheres by nitrogen purging, including the removal of hydrocarbons, oxygen, and
other toxic or reactive gases. Our engineers will determine the optimum rate, temperature, and volume required to remove unwanted products in the safest and most efficient way possible. Because nitrogen is inert, it will not support combustion. Therefore, once a system has been purged using nitrogen, there is no risk of ignition within that system or pipeline. The nitrogen atmosphere reduces the corrosion caused by oxidation, making it ideal for preserving piping for prolonged periods without use.
Hot nitrogen services & catalyst regeneration
Hot nitrogen services can be used when working with hydrocarbon deposits in vessels or pipelines to significantly reduce the amount of time and required nitrogen to clear away unwanted deposits.Hot nitrogen purging is often used to remove stubborn deposits from the following systems:
- Catalyst Reactors
- Molecular Sieves
- Sulfur Recovery Units
- Heat Exchangers
- Dehydration Processes
- Oxidation Reaction Systems
Nitrogen / helium and sonic leak detection
Nitrogen/helium leak detection is the most precise way of detecting and quantifying leak rates on critical flanges. Helium leak detection involves pressurizing a system with a mixture of nitrogen and ~1% helium. Our qualified technicians then probe each potential leak with highly sensitive helium detection equipment. This process is extremely effective for identifying and quantifying leak rates prior to the introduction of volatile products to the system.
An alternative to helium leak detection is ultrasonic leak detection equipment. In this procedure, the system is pressurized and inspected with extremely sensitive ultrasonic equipment that detects the sound created by a leak on a flange. While it is very effective for identifying leaks, this process cannot be used for quantifying the leak rate.
When combined with an effective bolt tensioning or torqueing program, these leak detection systems are a highly effective method of ensuring that any system is ready for startup.
Accelerated cool-downs
Actual data recorded during an accelerated
cool-down using nitrogen gas injection.
Virtually any reaction vessel operating at extremely high temperatures can benefit from the thermally engineered accelerated cool down service provided by FourQuest Energy. The high-temperature vessels used in the energy industry for a wide range of processes and products can often take days or even weeks to cool down to manageable working temperatures. Proper engineering design optimizes the accelerated cool-down portion of the plant shutdown process, allowing our clients to better plan and execute shutdown activities over and above the time savings provided by the ACD. Put simply, shutdown time is significantly reduced so that work can start sooner and our clients’ expenses are lower.
Actual data recorded during an accelerated
cool-down using liquid nitrogen injected
into a supplied air flow.
Our customized procedures—written by our engineers for each individual application—have been proven to safely and efficiently reduce the time required for cool-downs on process reactors including hydro-crackers, hydro-treaters, catalyst beds, and reaction furnaces without causing any adverse effects to thermally sensitive material. Having the capability to provide high-rate nitrogen on-site and ready to pump prior to accelerated cool-downs can reduce and even eliminate any thermal runaways when conducting heat soaks in sulfur recovery units. With continuous on-site monitoring of the system and its response, our engineers and technicians can adapt and respond instantly by making changes to the process in real world conditions.
Pneumatic testing
Because is it clean and extremely dry, high pressure nitrogen is a very effective medium for conducting pneumatic tests on sensitive equipment when potential contamination is a concern. The high rates, pressure, and precise control of FourQuest Energy’s mobile nitrogen pumping equipment can significantly reduce time required and increase the level of safety for conducting this type of critical testing activity.
When combined with helium leak detection, large system leaks can often be identified and repaired prior to reaching the final test pressure. By identifying the leaks at lower pressures, the systems can be repaired without having to bleed off the pressure and re-pressurize once the final test pressure has been reached. FourQuest Energy’s equipment can also be operated and monitored remotely for any projects requiring a safe distance.
Nitrogen membrane units
FourQuest Energy’s nitrogen membrane units are ideal for shipping to remote locations, both onshore and offshore, where it is logistically difficult—or impossible—to ship liquid nitrogen. Well suited for low rate and volume applications where the delivery of liquid nitrogen bulkers is not feasible, our nitrogen membrane units can greatly reduce both logistical concerns and transportation costs.
Nitrogen drying and preservation
Nitrogen gas provided by FourQuest Energy nitrogen pumping equipment provides 99.99% pure nitrogen with a dewpoint of -70˚C. This clean, extremely dry gas is effective for drying out any pipeline or process system. When combined with high temperatures, the drying time to achieve the required dew point is significantly reduced compared with conventional drying methods.
Because nitrogen gas is inert, it is ideal for filling pipelines or process systems that may go unused for long periods of time—months, even years. By maintaining a positive nitrogen atmosphere inside a pipeline or process system, ongoing corrosion can be reduced and even eliminated, provided the system is dry and there are no leaks present. This service is particularly effective for drying of chemically sensitive systems such as oxygen and hydrogen.
Nitrogen Freeze Plug Isolations (Pipe Freezing)
When a piping system or pipeline does not have sufficient valves or other appropriate isolation mechanisms in place, nitrogen freeze plugs can be used to create a temporary positive isolation. Nitrogen freeze plugs can often save a significant amount of maintenance or testing time by providing isolations and eliminating the need for a complete draining of the system or shut-down of the unit. For testing applications, freeze plugs can reduce the total volume required for testing by isolating the portion to be tested. Nitrogen freeze plugs can hold up to 10,000psi.