In systems designed to remove acidic gasses from product streams using amines, foaming is a major issue affecting the efficiency of the extraction, which can ultimately increase operating costs.

Foaming is an adverse byproduct of chemical engineering processes that aims to adsorb carbon dioxide (CO₂) and hydrogen sulfide (H₂S) from natural gas streams. When hydrocarbon liquids enter the system, they decrease the surface tension of the amine solutions due to their high solubility. This leads to gas bubble formation in the stream, which results in foam formation. Foam stability also increases due to increased viscosity, extending the break time of the bubbles formed.

Foamability also increases due to a variety of other contaminants such as suspended solid particles like iron sulfide and dust, and thermal and oxidative degradation of the amine.

The adsorption efficiency of these sour gasses typically increases at lower temperatures but also increases the potential for the formation of these liquid hydrocarbons in the inlet stream.

Foam mitigation is a critical parameter when concocting a lean amine solution to act as the acid extractor in natural gas contactors. Alkanol amines are the most common solutions in these lean amine solutions and these solutions are often specifically designed for the operation parameters of the system. Numerous studies all over the world are currently aiming to identify other compounds that can counteract surfactant contamination.

Antifoam agents are often introduced to aid in foam breakage inside gas sweetening systems, but with it comes a distinctive paradox: while adding antifoam in small quantities decreases foam formation, at higher quantities it actually catalyzes more foam formation.

Foamability and stability testing gives operators a reliable idea of the foaming tendency and retention in the contactor for various amine solutions.

Visaya’s fully automated Foam Digital Detection Imaging™ (FoamDDI) system accurately and reliably automates foam testing to diagnose and differentiate high and low foam amine solutions without implementing them into the operation stream or undergoing manual analyses that have been proven to have extensive operator bias.

The FoamDDI’s patent-pending design precisely controls predetermined conditions of time, temperature, and airflow which eliminates the subjective and biased nature of manual operation.

The protocol is designed using the ASTM D892 method as a blueprint. After designating parameters for the test, the sample is heated accordingly, and once stable, controlled air is introduced via a diffuser and the foam generation is recorded through its collapse after airflow is stopped.

In the manual protocol, the operator is required to turn on and off the airflow, visually record the height, and then determine the time it takes for the foam to collapse. With such a dynamic characteristic as foamability, operator bias and the myriad of variables affecting data collection often lead to inconsistent and unreliable results.

The FoamDDI device eliminates user bias by mechanizing Visaya’s augmented vision system which operates with invaluable edge contrast precision to determine foam height and stability. The automation allows the operator to run up to four analyses asynchronously and unattended with the addition of up to four modules per logic box. The device provides photo and video records of the entire test to be analyzed manually following the procedure, and even has a manual override option denoted by an O on the results screen in the rare case the edge is not easily identified by the device.

With the FoamDDI’s newly added amine application calibration, gas-sweetening amine solution analysis has never been easier and more reliable.