The technology for combustion air systems design has been undergoing a significant catharsis largely due to the easy and low risk of experimentation with CFD Modeling.  Revolutionary air systems designs can be quite beneficial over the past conservative approaches that may have unknowingly constrained or handicapped mill profitability. CFD Modeling has been a big reason for the major “rethinking” for recovery boiler combustion design, because different designs can be consider “on paper” without actually making any field modifications.  With this CFD Modeling tool, the current “baseline” operational conditions are first modeled to provide the comparison for other setup changes of the current physical air system arrangement or if necessary future changes such as a large production increase requirement.  CFD modeling may provide clues how to setup the existing air system to achieve the objectives, but if not possible, then we will have a sound basis from which to design and test future changes.  Anthony-Ross Company will then suggest other air system designs for evaluation, and if approved by the mill, these other designs will be evaluated.

We understand that “guessing” at a solution can be very expensive to all involved if the “guess” is wrong.  We have used CFD modeling numerous times, and the evolution of the modeling process has been able to point us toward a solution.  As we run each model case study, we are able to learn which is the better direction to change or improve.  With out this modeling process, we are basically following conventional guidelines.  We would suggest a conservative solution, but the impact may not be what is most desirable compared to what CFD modeling can point us toward.

Computational Fluid Dynamic (CFD) Modeling removes the “mystery” of combustion air system design.  Past methods of applying solutions to recovery boilers are strongly questioned when the availability of advanced tools like CFD modeling can provide a simulation of what is occurring inside the furnace where it is impossible to measure the interactions.  With Anthony-Ross Company / Process Simulations Limited, Incorporated (PSL) partnership, the experiences in CFD modeling of recovery boilers is the largest with more than 60 recovery boilers modeled.  However, it is not just the “concept” of modeling that is important, but the “output” of the model must be understandable as well.  The advantages of the CFD Model from Anthony-Ross Company are that we evaluate many performance criteria.  It is often misleading to focus on just a few parameters (example; gas velocities, temperature, and combustion constituents) while ignoring others (example: heat flux on walls, mass carryover, particle trace, and simulation viewer).  We feel that the simulation packages (movies) present the CFD model results in the more user-understandable presentation. 

The CFD Model will provide both static and animation displays of gas velocities, temperatures, particulate carryover, heat flux, liquor tracing, and several others as shown in the following sample pages.  A summary report will be provided when all cases are completed.

CFD Modeling provides a low risk and cost method for evaluation of combustion air system designs specific to your boiler, without the risk of making incorrect tube openings.  Performing the CFD Model before the actual project, helps you make a better decision when the need arises.