CFD ANALYSIS OF THERMAL CATALYTIC OXIDIZER / SELECTIVE CATALYTIC REDUCER
IONEX Research Corporation produces high performance equipment used to protect the environment and personnel from hazardous airborne chemicals and contaminants (click here to visit the IONEX website). IONEX was requisitioned to deliver a Thermal Catalytic Oxidizer/ Selective Catalytic Reducer (TCO/SCR) for filtering offgas emitted from a nuclear waste treatment facility.
The unit consisted of a heat exchanger, a heater, three banks of oxidizing catalysts and three banks of reducing catalysts. As part of the requisition, their customer had several requirements with regard to how the offgas flowed through the TCO/SCR.
- IONEX was required to demonstrate that the offgas is evenly distributed across the oxidizing and reducing catalysts as it flows through the TCO/SCR.
- IONEX was required to demonstrated that the pressure drop of the offgas stream across the TCO/SCR stream did not exceed a prescribed limit.
- IONEX was required to demonstrate that the temperature of the offgas as it passed through each bank of catalysts did not drop below a prescribed limit.
Endesin was engaged to perform a coupled thermal/CFD analysis on the TCO/SCR to determine if it met the above requirements and subsequently design any baffles or additional ducting necessary to achieve the desired fluid and thermal properties.
The steps used to perform the analysis were as follows
- A SolidWorks model for the unit was received from IONEX and brought into NX to begin postprocessing.
- The fluid domains were extracted from the model and split along the centerline of the TCO/SCR to take advantage of symmetry.
- The boundary conditions included an inlet flow condition, an outlet opening condition, conductive and convective heat transfer through the housing, a heat input from the heat exchanger coils and a pressure drop through the catalysts.
- The analysis was repeated multiple times using different designs for internal baffling until the desired flow distribution and pressure drop was achieved.
- Varying levels of insulation were simulated on the outside of the housing to determine what would be required to meet the minimum temperature requirements for the catalysts.
NX Advanced Simulation was used as the pre and post processor and the solvers used were NX Flow and NX Thermal.
By partnering with Endesin, IONEX is able to offer its customers the full gamut of advanced engineering analysis capabilities without incurring the expense of maintaining the tools and expertise full-time for services that are only required on occasion.