The design of the polflame®, the clinkering zone burner of thyssenkrupp has been fine-tuned towards even higher reliability and ease of operation. The second generation polflame® variable nozzle (VN) is the ideal solution to handle the most difficult fuels, while at the same time delivering maintenance-free nozzle adjustment, easy operability, enhanced efficiency and sustainable flexibility.
Innovative clinkering zone burner to reduce fuel as a cost factor
In the cement industry, fuels are a significant cost factor. To reduce clinker production costs, high-grade standard fossil fuels, such as coal, oil and gas are being replaced by lower quality substitute fuels. Whereas combustion in the precalciner is non-critical from a process-technological point of view, the thermal conversion of substitute fuels in the rotary kiln is a much more demanding process, in which such criteria as process stability and product quality play a decisive role.
The polflame® VN is ideally suited to use with both standard fuels, like coal dust, fuel oil and/or natural gas, as well as with substitute fuels.
In designing the second-generation model thyssenkrupp departed from conventional thinking, which assumes that even as early as the project phase operators already need to know what fuel they will be using in the near- and mid-term future. The new polflame® VN is designed in such a way as to enable any changes in fuels, substitution rates or capacity increases to be implemented without major modifications. Moreover, the highly efficient nozzle system has been modified to allow easy adaptation of the nozzle size in order to maintain momentum, for example after a fuel change or capacity increase.
The new design incorporates several benefits for the customer.
polflame® VN – advantages at a glance:
Modular design with interchangeable fuel channel configuration
Simplified, maintenance-free nozzle adjustment system
Simplified flame adjustment, based on only two parameters: swirl and primary air fan velocity
Optimized nozzle arrangement and diameter
Successful handling of highly abrasive fuels
Customer-tailored clinkering zone burner design
The clinkering zone burner by thyssenkrupp has a modular design with interchangeable fuel channel configuration to adapt to change in fuel, increased substitution rate or increased kiln production capacity. The interchangeable primary air nozzles enable the polflame® to adapt to changes in fuel while keeping the energy consumption as low as possible.
The simplified, maintenance-free nozzle adjustment system boosts reliability and durability, allowing thyssenkrupp to give users an extended warranty of 5 years.
The mouthpiece has also been simplified to enable quick replacement for the adjustment of the divergence of the flame, if required.
Simplified flame adjustment, based on only two parameters: swirl and primary air fan velocity. The swirl is adjusted via variable nozzles. The adjustment can be done either directly at the burner or remotely from the control room. Adjusting the swirl allows to control the flame shape and temperature depending on fuel properties, making it possible to use efficiently even difficult to ignite fuels.
The nozzle arrangement and diameter have been optimized with the focus on increasing injection capacity while reducing energy input. This provides the benefits of reduced specific energy consumption and lower emissions, while retaining the familiar combustion performance.
Successful handling of highly abrasive fuels such as anthracite and low-grade coals with high ash content. The CFD-optimized coal channel ensures low wear rates leading to reduced operating costs and a longer service life.
The second generation polflame® variable nozzle (VN) is the ideal solution to handle the most difficult fuels, while at the same time delivering maintenance-free nozzle adjustment, easy operability. Whether you operate your kiln with standard or substitute fuels, or a combination of several fuels, the polflame® VN can be individually adjusted to the various fuel types. No matter whether the production capacity in question is less than 1,000 tonnes, or more than 12,000 tonnes of clinker per day, polflame® VN clinkering zone burners can be implemented with thermal capacities from 10 MW to 300 MW.
Clinkering zone burner operational principle
The task of the sintering zone burner, or main burner is to create a defined temperature profile in the kiln in order to ensure an optimum clinker sintering process. The required temperature profile differs from kiln to kiln, depending on the used fuel and its physical properties such as moisture, particle size and calorific values. The role of the primary air nozzles of the burner is to adjust the flame length and shape in order to optimize the combustion process.
Thanks to its highly efficient primary air nozzles, the polflame® burner can be optimally adjusted to the ignition behaviour and burnout performance of the individual fuels during operation. The variable nozzle system allows easy adjustment of the primary air direction and volume in order to influence the point of ignition, residence time and emission generation with a variety of fuels. Notably, the patented nozzle adjustment system makes reproducible burner settings possible – a key precondition for process stability under demanding boundary conditions.
The polflame® VN is the only burner on the market with an outer coal channel which is responsible for its superior performance with challenging fuels. The coal particles are injected in a hot and oxygen rich atmosphere, resulting in the immediate heat up and ignition of the fuel, prior to it being mixed with cold primary air. As a result, even low-quality anthracite can be used without compromising clinker quality. Additionally, the coal conveying air acts as cooling air.
Clinkering zone burner service
With the polflame® VN thyssenkrupp offers an innovation clinkering zone burner and focuses on both high-end components and best-in-class service when it comes to maintenance and replacement.
In the area of the coal dust connection, the coal dust channel is lined with wear-resistant material. The inlet zone can be inspected by opening the inspection cover, and the wear protection can be replaced if required. Should requirements change with regard to, for example, burner capacity or fuels, the polflame® VN is designed such that the centre, the burner tip and the primary air nozzles can be easily adapted to the new conditions. Wear parts such as the outer burner tip can be replaced easily, and fuel lances can be retrofitted.