Next Generation of kiln burners

The FLSmidth? JETFLEX? burner is a rotary kiln burner that drastically cuts operational costs, giving maximum fuel flexibility, reliable operations, improved heat efficiency and reduced power consumption.
Nowadays, many industries are looking for possibilities to reduce CO2 emissions, energy consumption and increase the reuse of waste materials, These demands are enforced by various regulations and international agreements, and in the long term, they will cause cost reductions. In the cement industry, this can be achieved by using modern techniques in production and by an optimisation of the burning process, by fuel substitutions, alternative clinker compositions or by the production of blended cements with different additives. A variety of completely or partly amorphous materials are used as additives, like slag, fly ash, silica, pozzolana and others. Controlling these additives quantitatively is essential in order to guarantee the cement norms.

Increasingly, plant managers are looking to reduce their dependence on costly high-grade fossil fuels and make best use of available fuel resources. But often, they are held back by burner technology that limits the use of low-grade coal types and solid alternative fuels. FLSmidth is proud to introduce the next generation of kiln burner that meets the demands for fuel flexibility, reliable and stable operation and outstanding heat efficiency. The FLSmidth JETFLEX burner is a revolutionary rotary kiln burner that enables the highest degree of fossil fuel substitution.

Engineered for reliability, high uptime and low operating costs, while delivering a competitive return on investment, it is also well suited as a retrofit solution. The JETFLEX burner is the next-generation successor to FLSmidth?s DUOFLEX? burner, which has successfully served the market for many years. Building on the DUOFLEX burner?s key design attributes of low NOx emissions, high performance and long kiln lining lifetime, the JETFLEX burner?s nozzles can be easily configured to allow the use of annular and jet air streams.

Flame optimisation
The JETFLEX burner is designed to incorporate two main features of technological innovation: a new type of jet air nozzle and a shared adjustable centre fuel channel. The new jet nozzle design gives the JETFLEX burner the ability to optimise the flame shape and combustion according to the type and quality of fuel. The jet configuration allows fuel to be rapidly mixed with hot secondary air faster, which is a major contributor to the outstanding combustion efficiency.

Improved thermal efficiency
The adjustable centre fuel channel contributes to better clinker quality and a high degree of alternative fuel substitution. It allows the fuel to expand and decelerate to gain retention time and improve fuel surface exposure, which accelerates fuel conversion and combustion.

This, combined with fast mixing with hot secondary air, ensures early ignition and maximum fuel burnout, while also reducing or eliminating fuel particles combusting in the clinker bed.

Furthermore, the central fuel channel functions as a combined fuel channel for simultaneously burning multiple solid fuels, such as coal, petcoke and solid alternative fuels. Due to the straight, uninterrupted pipe design, fuels can pass through the central fuel channel without disturbance, which reduces wear and cold air flow, thus improving heat economy. If requested, the JETFLEX burner can be designed with the traditional coal annular injection channel.

High reliability
The FLSmidth JETFLEX burner is available in two models, JETFLEX and JETFLEX PLUS. Both models feature a simple design and few moving parts, delivering high uptime through outstanding reliability and low maintenance requirements. Due to outstanding fuel efficiency and low operating costs, the JETFLEX burner ensures a high return on investment and fast payback time.

The design of the JETFLEX burner has been optimised specifically to meet the requirements of traditional fuels such as oil, gas, coal, petcoke and medium-grade alternative fuels. The JETFLEX PLUS burner offers adjustable air nozzles allowing fine optimisation to increase performance and maximise thermal substitution rate by more complex alternative fuel firing, making it less dependent on moisture and heat content. This is mainly because of the low fuel velocity and outstanding flame control capabilities, together with rapid mixing with hot secondary air while maintaining well-defined fuel suspension in the flame core.

Ongoing testing The JETFLEX burner is a result of an extensive development programme conducted at FLSmidth?s research facility at Dania. Here, cold testing was completed, which included thorough testing of the gas-mixing profile. Currently, the first JETFLEX PLUS burner prototype is operating at a site in Europe, undergoing an extensive testing programme and will be available for sale later this year.

(Authored by Madsen Nielsen & Carsten D. Jensen, FLSmidth A/s – Denmark)