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Methanex is the world's largest supplier of methanol to major international markets in North America, Asia Pacific, Europe and Latin America. This means every day - the world over - Methanex plays a vital role in people's lives. Methanol is an important ingredient in many of the essential industrial and consumer products that make the world a better place in which to live, work and play.
Methanex recently replaced a critical component within a process gas heater at one of their Methanol production plants. The problem was that when they restarted the plant thermocouples installed on the heater were running hotter than expected. It was thought that there could be a flow distribution problem within the heater leading to flow starvation or poor process gas flow in the heater manifold. The manifold is used to split the process gas into different flow paths which separately pass through the heater. This enables the heater to more efficiently heat the process gas. If the manifold does not do a good job of evenly splitting the process gas flow this would mean that certain parts of the heater would receive less gas and therefore be heated to a hotter temperature. Methanex needed to know why the thermocouples were running hot and if a flow problem in manifold could be to blame.
Matrix used computer simulation to model the manifold and predict what would happen to gas as it moved through the manifold. This type of simulation is commonly referred to as Computational Fluid Dynamics (CFD). The advantage of CFD is that it enables fast visualisation of complex flow features, while allowing a large range of geometric and flow scenarios to be readily considered. CFD allows the engineer to interrogate and understand the flow in a lot of detail and provides more information than is normally available from a physical experiment. The CFD tool employed by Matrix was STAR-CCM+ (v7) which is a momentum coupled finite volume CFD code used extensively in process, plant, power, automotive, aerospace and environmental industries. Geometry of the manifold was developed and analysed within STAR-CCM+ and results provided to Methanex within three working days. For more information on STAR-CCM+ see www.cd-adapco.com.
The CFD model showed that flow starvation in the manifold was unlikely and that only a minor misbalance of flow occurs. The overall value to Methanex was being able to rule out the manifold as the cause of the overheating problem. The CFD model also showed that the manifold design could be improved at a later date to provide a more even flow split and reduce energy consumption at the plant.
To learn more about CFD, click here.