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Infrared Thermography Surveys for the Oil, Gas & Petrochemical Industries

The Power Industries
APT Infrared Thermography plays a hugely important role within the oil, petrochemical, chemical, and power generation industries. With the current global energy crisis, and the huge demand for energy on the increase, these energy-based industries must continue to meet higher volume demands while endeavoring to reducing operational costs and preventing failures. Such failures can lead to losses in production which in turn can cause massive monetary costs as well as ongoing effects that can be felt as far down as the consumer. This webpage will discuss the areas where APT Infrared Thermography is used within the petrochemical and energy sectors such as furnaces, generator cores, and offshore oil and gas platforms.

Introduction to APT Infrared Thermography in the Petrochemical Industry
The petrochemical industry is a fascinating, varied and challenging industry in which to carry out the many different types of nondestructive testing and predictive maintenance inspections. Within any refinery complex there numerous plants that carry out a specific function and process; and within each plant there is a multitude of equipment from steam powered, to hydraulic, electrical & mechanical. There is positive/negative pressurised equipment and a varied amount of exotic metals and alloys. The terminology used to simplify this is “the Balance of Plant”. Experienced inspectors know, the words “balance of plant” simply mean you must be prepared to meet the confusing and unexpected.

When we think of petrochemical plants and operations we usually think of an oil refinery; however, the process of oil refining is undertaken in multiple stages. There are separate chemical plants within a petrochemical refinery, and usually, where there is a region of petrochemical and hydrocarbon activity, there are also other forms of process or chemical plants such as methanol, ammonia, etc. Due to the complexities of this I will undertake a brief explanation of each area:

Oil & Gas Offshore Platforms
Before any oil can be refined or any gas can be used to run power generation turbines, it must be retrieved from deep below the ground. In the offshore environment this usually means drilling wells and maintaining and managing them via an offshore platform. Once the wells have been drilled and the flow of gas and oil is harnessed and controlled, the offshore process is relatively simple in concept. A platform’s main function is to retrieve the gas and oil from the wells, whilst controlling the flow, separating the solids, liquids and gases, and thereafter distributing the needed products whether it be oil or gas via usually via the undersea pipelines to the mainland.

Offshore Platforms Offshore Platforms

Undertaking APT Infrared Thermography on an offshore platform can be on standard equipment such as electrical switchgear and pumps. However materials coming up from the wells can cause detrimental erosion problems to the pipelines, valves, and vessels. One of the most common ways of monitoring sand etc is via ultrasonic sensors mounted at strategic locations on flow lines. Unfortunately, like all technologies, these ultrasonic sensors do have their limitations. An effective means of monitoring sand being carried up from the wells is by conducting a thermographic survey of the separator vessels.

The main function of an offshore separator is to quickly separate sand, water, oil, and gas. We know that out of these four materials, sand sinks in water while oil floats, and gas is light and cold and will remain on top. Also, each of these materials has a very different thermal capacitance and conductivity making it possible to use APT Infrared Thermography to locate and highlight the relative levels of solids and fluids.

Using thermal images we can distinctively differentiate between the layers of sand, water, oil, and gas. We can even see the sand’s flow pattern through the outlet nozzles, which can help to determine which valves will be more affected by the erosive power of sand.

Our APT Infrared Thermography engineers undertaking thermographic surveys for separator sediment levels have a firm understanding of fluid dynamics, thermodynamics, and erosion mechanisms, along with a good understanding of heat transfer, emittance, and reflectance. With this knowledge our APT Infrared Thermography engineers are qualified to make accurate diagnoses which in turn leads to proper, cost-effective means of minimizing the problems or, hopefully, eliminating the problems. It may be something as simple as packing gravel/stone in the well to reduce the flow of sand, thus alleviating the overall mass travel of sand and as a result reducing the wear on valves etc.

Pumping from Sea to Land
Once the platforms are operational and are producing, there are usually two main products that are sent to two different places. The crude oil is generally piped via undersea pipelines to large holding tanks for further refining. A common application of APT Infrared Thermography at this stage is monitoring holding tank levels.

Holding Tanks
The natural gas is pumped through miles of pipelines to its main destination which is usually a power generation plant. Some plants use fuel oil instead of natural gas to generate power by steam generation via boilers, however for now we will leave the focus storage tanks and focus on the much faster moving natural gas.

Power Generation Plants
Pressure, heat, and natural gas are used to spin gas turbines, which in turn spin the generators; this generates electrical power through electromagnetism. Within the turbine section, heat leaks can be found at the gas seal areas of a turbine. This inspection can be carried out online.

Gas Turbines and Heat Leakage
The generator section contains a stator and rotor. Both can be inspected with APT Infrared Thermography, however the generator needs to be offline and disassembled. This type of survey is frequently done when the stator needs to be repacked. Stator cores are made of iron bars which contain many small thin plates called laminations. Both the stator and rotor can be inspected with APT Infrared Thermography by wrapping several coils with insulated cables along the axis of the stator. Then, a pre-calculated amount of current is applied through the coils in order to generate a suitable flux.

Generator stator core - coils wrapped around and ready for fluxing
This inspection is to locate potential shorts within the many laminations that make up the entire core. Shorts in laminations can cause large temperature rises which will ultimately lead to a stator or rotor burn out. Below is a thermal image showing shorted laminations in a Multi Megawatt generator stator core.

Generator stator core problems - Lamination shorts
Repairs can be as simple a process as separating the lamination plates with a knife/tool or by using a pencil grinder to grind out the short. Once power is generated, it is then sent to the power station’s transformers and then to the main substation for power
distribution to various other chemical and petrochemical plants.

Incoming and Receiving Stations
Once the power reaches the petrochemical plants, it is stepped down via transformers and then distributed to various switchgear, and distribution panels. It is this area where APT Infrared Thermography would perform their thermographic survey.

A Smoothly Flowing Plant
Much of the power distribution within petrochemical plants goes towards driving motors, pumps and compressors. This rotating equipment is vital to a plant’s operation and can be thought of as a plant’s heart whose job it is to pump, compress, pressurize, and cool down the various fluids that maintain the plant’s production. APT Infrared Thermography inspection of rotating equipment is very common.

It can be a hot process?
The natural gas retrieved from offshore platforms is used in many production processes within petrochemical and chemical plants, also, we must not forget about the crude oil in our storage tanks that needs that also needs to be refined.
The pumps, previously mentioned, also provide refined fuel oil to fire up boilers in order to generate steam. The steam is then used for multiple purposes such as power generation and to drive plant turbines, which in turn drive pumps and compressors. Either natural gas or refined fuel oil is used to fire and heat up process heaters. In order to maintain efficiency and safety, boilers and heaters are inspected with APT Infrared Thermography to monitor insulation and refractory conditions and also to monitor tube temperatures.

Insulation Damage to Water Tune
Another use for natural gas within a chemical plant is to produce hydrogen through a process called reforming. Natural gas is sent into many catalyst-filled tubes within a reformer furnace and is mixed with the steam generated by the boilers. The reformer furnace is heated via many burners that usually use natural gas as their fuel. This heat creates a catalytic reaction that produces hydrogen from the natural gas and steam.

Infrared Thermography is undertaken on reformer furnaces in a similar way to boiler and heater inspections.

FCCU Regenerator Unit
The FCCU is an important part of the oil refinery. The FCCU breaks down long chains of hydrocarbons into shorter ones in a chemical process called cracking. This allows refineries to make products such as gasoline and other high octane fuels.

The FCCU uses a very hot catalyst to crack the hydrocarbons into shorter chains. The mixture then travels from the FCCU to another distillation column so that the cracked hydrocarbons can be extracted. A continuous FCCU has a primary reactor, a distillation column for separating out the cracked hydrocarbons, and a regeneration unit for cleaning the catalyst and preparing it for reuse.

Problems in the FCCU Regenerator Unit
Previously, we learned that boilers generate steam and that this steam is used throughout petrochemical and chemical plants. Most of the time the steam needed must be dry and superheated. The problem with steam is that as soon as it leaves the boiler it starts to cool down and condensate. This condensate can cause many problems in piping and equipment and must be expelled from the steam lines. Steam traps are used for this job. A steam trap’s job is to keep the dry steam in the pipes and get rid of the harmful condensate. Although there are many designs of steam traps, most achieve their purpose by opening purging out the condensate at regular intervals.

As Steam energy is money, it is in a plant’s best interest to make sure their traps have not failed in the open position which will just waste the precious and expensive steam. APT Infrared Thermography in conjunction with ultrasound testing is frequently used to determine the working condition of steam traps.

Steam Traps
In order for steam, gas, oil, and other fluids (hot or cold) to be properly distributed throughout a chemical and petrochemical plant, each must be sent though many lengths of piping and be controlled or redirected through valves. APT Infrared Thermography can also be used to verify if valves are either in the open or closed position (passing or not). This is a relatively simple inspection, however, the inspector should be aware that although you can tell if the valve is passing fluid or not, you usually cannot tell how far the valve is open.

Open or passing valve
Process piping can also become obstructed or form internal blockages and restrictions which are usually based on the type of fluid it carries and the temperature it maintains. APT Infrared Thermography is very useful in identifying internal line blockages and restrictions. A few of the causes are:

• Internal buildup may cause fluid/flow restrictions
• Internal buildup may cause pipe blockages

Insulation related problems
Chemical and petrochemical plants are not all about hot vessels and piping. Some plants have cryogenic processes such as CO2, ammonia, and liquefied natural gas, so there will be cold pipes, pumps, vessels, and tanks. APT Infrared Thermography is used to inspect these types of cold equipment for insulation-related problems, which can lead to greater problems and also energy and efficiency losses.

Icing of Pump Lines.
Below is a thermal image of a distillation cold box.APT Infrared Thermography can be used to identify insulation problems within cold vessels and piping within chemical plants.

Insulation problems
Thermographic surveys can highlight insufficient insulation. Cold liquefied natural gas inside the tank and warm air outside the tank caused condensation to form throughout the tank’s external shell and domed roof. This condensation problem along with the sea breeze hitting the tank carries over microorganisms from the sea and air. The damp and warm conditions allow these microorganisms to thrive on the concrete shell and steel dome of the tank, resulting in mold and algae growth. In turn Mold and algae love to corrode steel, which leads to external corrosion and pitting of the steel dome of the holding tank. There is no quick or economical fix in this instance except for frequent cleaning and painting of the affected areas to prevent or slow down the corrosion.

It is now common knowledge that APT Infrared Thermography plays a large part of fault diagonsics within the within all aspects of the chemical and petrochemical industry. Not only to monitor live equipment conditions but also to help identify design, repair, and construction oversights. Although these are some of the more common applications for APT Infrared Thermography within these plants, there are many more uses and applications. Many of the thermographic applications carried out within chemical and petrochemical plants are very challenging and require a solid understanding of plant equipment, processes, and heat transfer physics in order to properly identify and diagnose problems and conditions.

We carry out many thermal imaging surveys each year and guarantee to offer a professional, reliable, and helpful and offer competitive pricing. We offer a last minute service at no extra cost, and we also undertake weekend Infrared Infrared Thermography surveys on both on Saturday and Sunday in order to meet your out of hour’s survey requirements. We offer a nationwide service offering a single supplier for all of your regional offices and projects.

Most of our clients, who use us for the first time, continue to use our services because of our proactive approach, this has led to nationwide agreements with many the top UK Companies, which allows them to benefit from even more competitive rates as well as unrivalled service.

We also offer other specialist testing and reporting, such as:

• Air leakage Testing to Dwellings and Commercial Buildings
• Fire Enclosure Testing
• Sound Testing
• Energy Performance certificates, EPC, SAP & SBEM

APT Thermography - Further Information

If you have any questions or queries please don’t hesitate to contact us:

By Mobile - 07967 233836 (available 7am to 10pm)
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Infrared Thermography Surveys


APT Thermography

Head Office: Unit 2, Sayells Farm, 7 Harlington Road, Upper Sundon, Bedfordshire, LU3 3PE
Tel: 07967 233836 or 07775 623464