LACT Units

LACT Unit The Lease Automatic Custody Transfer, or LACT, unit serves a fundamental role in the the transfer of crude oil and petroleum products from the production site into the custody of pipelines, trucks, or storage tanks by precisely measuring the amount of flow. This is crucial to ensure that each party is accurately compensated and in determining overall volume. LACT units are comprised of many different parts and in order for the measurement conducted to be as accurate and precise as possible, it is imperative that these parts synergize with each other as seamlessly as possible. As such, LACT units make ideal candidates for fully integrated, modular process skids.

The Major Components of a LACT Unit

The following is a short list of the major component parts of a LACT unit, what they do, and how they function in relation to each other:

    • The LACT Control Panel – The LACT control panel functions similarly to most electronic control panels in that it forms the primary point from which the entire unit can be operated. It serves as the electronic brain of the LACT unit. A typical LACT control panel will include the main on-off circuit breaker, the hand on-off switch, the lightning arrestor, divert controls, monitor failure control, meter malfunction control, set stop allowable control, and the alarm beacon.


    • The Meter – If the LACT control panel is the “brains” of the LACT unit, then in many ways the meter serves as its heart. This is because the meter is the part of the unit that actually measures the fluid stream and total throughput. The most accurate meter is the positive displacement meter which uses a precise rotation through a mechanical gear train to a mechanical counter to gauge the throughput of the LACT unit. The meter may also come with various accessory parts designed to help calibrate it and keep it running accurately.


    • The Charge Pump and Motor – The charge pump and motor provide the energy source for the LACT unit. In order for them to function properly it is essential that their design take into consideration the flow rate of the system as well as its specific gravity or API gravity, which determines the gravity required to discharge the pressure requirements of the pumping system.


    • The Meter Prover Loop – The meter prover loop functions as a secondary loop and meter designed to verify that no leakage is occurring within the LACT unit which would thus render measurements inaccurate. In this way the meter prover loop provides an extra layer of protection to the integrity of the measuring system. The meter prover loop is composed of a manifold using three valves that are connected to two tees.


    • The Strainer – A strainer may be installed immediately upstream in the LACT unit from the charge pump or the displacement meter. The strainer functions to remove derbies from the flow in order to prevent the charge pump or meter from becoming damaged. It consists of a perforated basket that traps any solids larger than the perforations.


    • The Air Eliminator – The metering function of the LACT unit is to measure the amount of crude oil or petroleum products flowing through the system. As such, air within the fluid stream would skew an accurate reading. In order to prevent this, an air eliminator is used to remove air and vapor from the fluid stream before it reaches the meter. This is accomplished through the use of a float that is mechanically attached to an exhaust valve to eliminate the air.


    • The BS&W Probe and Monitor – The BS&W Probe and Monitor is an electronic device which is used to measure the amount of Basic Sediment and Water (BS&W) that is present in the stream. Its function is to ensure that the quality of the oil is up to standard and it is capable of diverting the fluid stream when needed.


    • The Sampler System – The sampler system is designed to gather samples from the flow stream over a specified period of time It uses a probe and sample container to do this, and the samples are then used to determine the composite API Gravity as well as the total percentage of BS&W, allowing changes and modifications to be made if needed and providing crucial information about the flow stream.


  • Valves and Sealings – In addition to the parts listed above, LACT units also consist of many valves such as the diverter valve, back pressure valve, and check valve. These valves function to open and close as needed in order to divert the stream or regulate pressure within the system. Additionally there are a host of sealings required throughout the system to prevent leakage and maintain security.

The Benefits of Integrating LACT Units into Modular Process Skids

Lease Automatic Transfer CustodyA LACT unit is a complicated piece of equipment and it is imperative that everything work in harmony with its connected parts. That is why LACT units benefit so much from modular process skids. The fully integrated, all-in-one process skids ensure that all the parts are fully compatible and they will save your company a great deal of time and energy over non-integrated units. Some of the benefits of LACT Unit modular process skids include:

  • Cost Savings
  • Single Source Accountability
  • Quality Control and Testing
  • Strict Adherence to Industry Standards
  • Faster Installation
  • Reduced Worksite Interruption

These benefits will save your company time, money, and energy and will also help ensure that you have a high quality LACT Unit that you can rely on. STI Group will also provide you with a single point of contact with whom you will be able to communicate throughout the entire process from preliminary ordering right through to delivery and installation. We will walk you through the process and answer any and all of your questions.

STI Group is highly experienced in the production and manufacturing of LACT Unit modular process skids. We carefully test our units for quality and to identify any defects prior to delivery. Our customers can rest assured that the LACT Unit they receive will be safe, reliable, and efficient. Please contact us for additional information and to discuss your situation and needs.