For almost 20 years, KFS has been using Computational Fluid Dynamics (CFD) as an integral part of the design process for combustion systems, primarily in rotary kilns. The experience gained from this difficult application combined with recent investment in a new High Performance Computer (HPC) and additional specialist engineers has allowed KFS to become a leader in combustion and flow modelling in a wide range of applications. KFS has now expanded its capability to offer CFD modelling as a consultancy service to the wider market.
The correct application of CFD modelling can take the guesswork out of process design and product development, or replace time-consuming, expensive or impractical physical modelling. It also provides a powerful tool to help overcome ongoing process problems, optimise existing operations and reduce running and maintenance costs. KFS apply a solutions-based approach to projects, developing representative models and using in-house flow and combustion expertise to identify solutions for existing problems or to optimise designs and operation. Every model developed is bespoke and created using the most appropriate technique for the application, working with customers to develop a full understanding of the system to be modelled. This allows creation of the most representative model to assist in problem resolution. A model of a customer’s system is produced together with a package of solutions developed by the experienced KFS engineering team. This can include conceptual design through to detailed engineering and equipment supply, as appropriate.
CFD modelling previously carried out by KFS has looked at a range of issues beyond combustion including: wear analysis in solid fuel conveying systems to increase mechanical life of components, air flow analysis in process ducts and burners where poor air flow and distribution has significant effect on performance, particle distribution and dropout in cyclones, dryers and ducting.
KFS have successfully used our solution-based CFD approach to provide technical support to a range of organisations from small independent operators to large multinationals, as well as to specialist equipment suppliers. Please contact KFS for further information on their CFD skills and expertise.
Rotary Kiln - Lime and Cement
KFS has been using CFD as an integral part of its kiln burner design process since it was founded in 1999. KFS recognised very early on the importance of the interaction between the combustion and the material bed in rotary kilns. As a result, KFS has developed a proprietary lime bed chemistry module to be fully coupled with CFD. This has been extended to cement bed chemistry which is more complex and involves multiple reactions for clinker formation. These have been validated against real engineering data from both lime and cement kilns. KFS have modelled kilns for all the world’s major lime producers and a number of major cement companies in China.
Rotary Kiln - Pulp & Paper, LWA, Clay and Others
In addition to lime and cement kilns, KFS has used CFD to model rotary kilns in pulp & paper, lightweight aggregate (LWA), clay and other material processing industries. One recent project undertaken by KFS is stibnite ore processing. From material feed through combustion, processing and material discharge, KFS has used CFD extensively to help understand the process and provide guidance on the design of combustion equipment and the kiln itself. KFS has developed specialised CFD add-on modules to model the chemistry that takes place in such a specialised rotary kiln. Other more recent work has been in the LWA industry. In each of these applications, the KFS experience in rotary kiln modelling combined with its unique ability to develop physics and chemistry models appropriate to the process ensures the success of the project.
Bed chemistry models for specialised applications may be developed in user coding (Fortran or C++), Excel VBA or Java.
SNCR - Lime and Cement Industries
With ever more stringent emissions regulations, it becomes increasingly difficult to achieve the required NOx reduction by burner design alone. SNCR (selective non-catalytic reduction) techniques have been employed as a cost-effective post-combustion treatment in lime and cement industries. With SNCR, urea or ammonia is injected typically in a preheater (lime) or calciner (cement). A sophisticated SNCR model has been successfully developed, implemented and validated by KFS in a leading commercial CFD code. KFS use CFD during the system design stage to optimise the injector location so as to maximise NOx reduction while avoiding ammonia slippage. This helps to ensure that environmental impact and operating costs are reduced.
Burner Internal Flows - Solid Fuel Analysis
CFD is used in every project to optimise burner design and eliminate potential mechanical failure. It is particularly indispensable in solid fuel firing (coal, petcoke or biomass), where the life of the burner components depends very much on the impact of particles on the surface of the material used. By conducting detailed CFD wear analysis, we can identify accurately where the mechanical failure may occur and engineer alternative solutions. CFD is also used to pinpoint regions of low conveying air velocity, where solid fuel particles are liable to settle and accumulate within the solid fuel channels. This leads to significant improvement in burner design and a large reduction in process downtime.
Oil & Gas - Fired Heaters and Boilers
CFD is increasingly being used in the oil & gas as well as petrochemical industries. KFS uses CFD for simulating combustion in fired heaters, boilers and furnaces including prediction of NOx emissions and assessment of heat flux to, and surface temperature of, the process tubes. KFS uses CFD to optimise the air distribution to multi-burner systems. Many of the KFS staff have extensive experience working in combustion applications in the oil & gas industry including R&D and design activities, commissioning and trouble-shooting (onshore and off-shore) and optimisation of air distribution system using physical modelling techniques.
Preheaters and Calciners - Lime and Alumina
Combustion and heat transfer also plays an important role in the preheater kilns and calciners used widely in lime, cement and alumina industries. The performance of these systems is also dependent on upstream and integrated burners and the various interactions due to vessel and ducting geometry and solid material behaviours. KFS has considerable expertise in modelling such specialised equipment and developing combustion system designs that not only optimise system performance but also reduce NOx emissions and operating issues such as refractory damage and material build-up.
Process Dryers - Flash Dryers and Classifiers
This type of application covers flash dryers, classifiers, cyclones and bag filters in food processing and chemical industries, where specified flow patterns and solids particle size distributions are desirable. KFS has been involved extensively in modelling a variety of such systems and providing cost-effective and practical engineered solutions.
Other Industries - Food and Polymer Processing
KFS have developed their CFD expertise over almost 20 years in the combustion field along with the complex chemistry that this entails, but have in recent years expanded into areas and developed their expertise to include flow modelling, particulate transport and heat transfer for applications in several different industries such as food and polymer processing. KFS are always looking to expand our portfolio into further industries, and discuss your CFD needs, so please get in touch for further information.