A CFD model of a coal pulverising mill showing air flow streamlines (ribbons) coloured according to velocity and particles.

Steinmuller Africa, is now positioned to take its suite of process, mechanical & piping engineering services to a wider range of industries. The company’s numerical analysis, part of its process engineering offering for boilers and heat exchange equipment in power plants countrywide, is used to accurately analyse the fluid dynamic behaviour of almost any boiler system, heat exchanger or boiler auxiliary equipment. 

Steinmuller is able to completely assemble numerical models of any OEM-designed and built plants. This numerical analysis service can be carried out in utility, petrochemicals, paper and pulp, sugar, and nuclear industries. 

Warwick Ham, Boiler Process Engineering Group Leader, Steinmüller Africa says, “Specialised tools and equipment, teams of resolute engineers and technicians, and our 60 years of experience provide us with the required expertise to take our solutions to these markets.” 

Clients’ benefits

Value for money is a characteristic of Steinmüller’s investigative approach. “We begin by assessing the client’s requirements and the nature of the problem,” Warwick explains. “This method positions us to make recommendations on the numerical analysis tools to be used, and we always recommend against over-complicating the investigation. These are just two of the factors which drive down costs.”  

Accurate geometry of every plant component, the plant’s operating philosophy, and some of the actual operating data is required to accurately build numerical models of any plants, whether designed by Steinmuller or by other OEM’s. “Once the model is built,” Warwick explains, “we investigate various scenarios to predict the operating characteristics under varying conditions. Often these operating conditions fall outside of the original design envelope.”

He says that their systems modelling approach is continually being developed. “These ongoing developments help provide insight into the most cost-effective modifications for improved operating and maintenance practices which provides us with a competitive advantage.”  

There are three main tools Steinmuller uses to execute its numerical analysis offering – the company’s original Thermal Boiler Design Software, used in the design of most of the utility boilers currently in operation; Fluid Dynamic Numerical Analysis; and Computational Fluid Dynamic (CFD) Numerical Analysis. These tools are used by the company’s engineers to accurately analyse the chemical, fluid and heat transfer processes occurring in boilers and other heat exchange equipment in any industry. 

”Although our original boiler design programme is still used, our entire suite of numerical analysis tools has been expanded and modernised over the years,” Warwick points out. 

Calculating capability

To ascertain the heat transfer and fluid dynamic behaviour of working fluids, both air/flue gas and water/steam, within the boiler, piping and other componentry, Steinmüller’s suite of numerical analysis tools plays a pivotal role. Its Boiler Design Programme determines a boiler’s mass and energy balance by calculating the heat lost by the air-fuel combination within the furnace and absorbed by the water-steam flowing in the walls of the furnace. It also calculates the expected heat transfer throughout the various convective boiler parts downstream of the furnace, as well as the quantity of heat absorbed by the water and steam flowing through these boiler components. 

Fluid Dynamic Numerical Analysis is then used to calculate the behaviour of the bulk flue gas flowing around the parallel pipes that form the boiler, as well as the water or steam flowing inside these pipes. “This helps us predict the effects of the working fluids, the air, the flue gas, and the water-steam, as well as how they flow through obstructions, lose or gain pressure, change phase, or even pulsate,” Warwick explains. 

A picture of the CFD model of an entire boiler including coal mills and pulverised fuel piping in foreground, burners and air ducting, furnace showing combustion flow paths and temperatures and downstream air heat exchangers background.

Lastly, CFD software for numerical analysis is used to calculate the extremely intricate mass, energy, and fluid dynamic balance on a very detailed scale including every point within the fluid volume. “These tools enable us to get around the practical difficulties of measuring critical parameters within the combustion zone at temperatures of approximately 1 600o C or within the steam system at temperatures up to 572° C and pressures of 258 bar. 

Almost any heat exchanger

“Although our numerical analysis offering is related mainly to boiler systems and associated auxiliary equipment, we can use these tools to analyse almost any heat exchanger or fluid dynamic equipment like fans, pumps, valves, and dampers, for example.” Warwick elaborates by pointing out that Steinmüller has performed mass and energy balance thermal modelling for diverse types of heat exchangers. These include fired and unfired boilers, water to steam heat exchangers, fluidised bed boilers, waste heat boilers, fans, air heaters, mills and electrostatic precipitators or fabric filters. “We’ve also engineered fluid dynamic models of the boiler water circulation system contained in evaporators, as well as large and complex piping systems, valves, and fans. 

In addition, Steinmüller recently conducted a CFD analysis of various power system subcomponents – combining these component models to form an entire boiler system, which included mills, burners, air heaters, and electrostatic precipitators that remove ash and dust.

More than six decades of refining its numerical analysis offering for boilers and ancillary equipment bodes well for the company as it expands its industrial footprint. “Our numerical modelling helps develop performance improvements in the systems’ various sub-components, which are combined into a single system model that assesses the overall benefits to the entire system,” Warwick concludes. “Our service has the potential to drive down operating and maintenance costs in any industry.”

https://www.steinmuller.bilfinger.com

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