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Oxidizers: The Art of Re-Imagining Control Schemes.

Oxidizers: The Art of Re-Imagining Control Schemes. 

 

RHZ Environmental is known for innovation. Our Bottle-Up Shutdown process (created well over a decade ago) has been embraced by the industry. It works on every Regenerative Thermal Oxidizer ever built; saving clients money, and time. It has become ubiquitous. The seed of this idea came from a discussion with a British OEM about commissioning an oxidizer in the Middle East.  

 

Even the best designs change when exposed to the real world. Ask anyone at a Biomethane facility about their oxidizer, and you will learn of their system's strengths, and weaknesses. One client suffered more than 1,000 shutdowns in less than five years of operation. In fact, they experienced  over 100 shutdowns between January 1st, and the middle of February, when RHZ was brought in to help. Twelve hours later the oxidizer temperatures stabilized, and the rash of shutdowns ended.

 

Below are two screen shots from the very 1st VAM (Ventilation Air Methane) installation in the United States.  This system was designed to maintain temperature without the aid of a burner - just by the heat content of the methane-rich gas stream coming out of a coal mine’s bleeder shaft. The problem is that once the methane levels dropped below 0.59% the units would inevitably shut down. On paper they were designed to handle methane concentrations as low as 0.40%. Unfortunately the impact of a myriad of issues wasn’t fully understood. This resulted in elevated maintenance costs, and a significant loss of revenue.

 

RHZ reviewed the control scheme and found a solution. This solution can be clearly seen in the picture of the two RTOs.

 

Both RTOs have the same 1,700F combustion chamber set point. The one on the left (RTO 2) is using the OEM’s original control scheme. Its combustion chamber temperature has dropped by nearly 100F. It is well on its way to a shutdown.

 

The RTO on the right (RTO 3) is using the new RHZ Environmental Control Scheme. It is having no difficulty maintaining its combustion chamber set point, which is crucial for maximizing the oxidizer's capture efficiency, and RIN credit generation. In fact, the inlet methane concentration dropped to 0.41% and these RTOs performed flawlessly. They can now operate into the 0.3X% range without any issues. This is beyond the limits they were originally designed for.  

 

If you would like this level of expertise to customize your process, just let us know. RHZ Environmental will be happy to help.

 

 

 

Inlet methane concentration
Two RTOs: two different control schemes