Specialist Flow Measurement Engineering

Chemical Injection

Flow Measurement Technologies

About Chemical Injection

Chemical injection is a critical process in oil production where various chemicals are injected into crude oil to enhance performance and protect equipment. For instance, scale inhibitors prevent scale buildup on pipes and fittings that transport oil to refineries. Flow meters play a vital role in monitoring and controlling the quantity of chemicals added to crude oil, including biocides that inhibit the growth of organisms in pipelines.

Corrosion inhibitors are the most commonly measured additives, but various types are used depending on the primary liquid. Pour point depressants are added to lower the pour point, making it easier for oil to flow through pipelines. Most chemicals are typically injected at low flow rates, ranging from 0.01 to 40 liters per hour. However, Low Dosage Hydrate Inhibitor (LDH) can have much higher injection rates, sometimes reaching up to 17,000 liters per hour, specifically designed to inhibit water-based mixtures that may freeze.

Some positive displacement flow meters can achieve a turndown ratio of 500:1. As these systems often operate dynamically slow, they require only minor adjustments daily, making manual controls still a popular choice. It is crucial for the flow measurement system to handle the pulsing nature of the pumps used, as well as withstand high pressures, which can reach up to 1380 bar (20,000 psi) in modern subsea injection systems. Topsides injection typically operates at lower pressures, usually between 200 to 1000 psi.

What’s the Best Chemical Injection Flow Meter?

Mode-Meter AG’s VFF rotary piston positive displacement flow meters have established themselves as the premier solution for chemical injection flow metering applications. These flow meters are designed to handle a wide range of flow rates and operate effectively at pressures ranging from a few bar up to 10,000 and 20,000 psi (690 and 1,380 bar) and beyond.

Chemical Injection Additives

Methanol is commonly used as a chemical injection additive, providing similar benefits while often being more cost-effective. Various other specialized chemicals serve similar purposes, all aimed at reducing operational costs on the way to the refinery. Interestingly, flow meters are crucial in measuring these chemicals, which can account for up to 30% of the operating costs of an offshore platform. Control systems are frequently manually adjusted based on the flow meter’s displayed value, whether accessed locally or through a SCADA system. However, there is a growing trend toward automating this process using control valves, enhancing efficiency and precision in chemical injection.

Chemical Injection Flow Meters

There is a growing trend toward measuring chemicals subsea—underwater—rather than waiting until the crude oil reaches the surface. This requires flow meters capable of operating under high internal pressures exceeding 10,000 psi (690 bar) while also withstanding external pressures up to 345 bar (5,000 psi).

VFF / Flowpod

Mode-Meter AG pioneered the development of the world-renowned VFF rotary piston flow meter—accurate, effective, and versatile instruments designed to suit a variety of applications in the Oil and Gas sector. The VFF Flow Meter is the preferred choice for chemical injection applications and other scenarios that require high pressure tolerance.