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Fuel flow balancing

Balancing the fuel flow from burner-to-burner and simultaneously ensuring that the air flow is also in balance, improves combustion efficiency by ensuring that minimum furnace excess oxygen is achieved. Fuel balancing and reduced furnace excess oxygen are beneficial to unit heat rate, boiler thermal efficiency, superheater temperature profiles, flame stability as well as NOx reduction.

For coal-firing, RJM has developed its own specially-designed probe to measure the existing burner primary air and coal flow deviations. The probe ensures accurate measurement of coal flow deviations and "roping" in the coal pipe runs, prior to the burner. This enables RJM to recommend the installation of appropriate pipe orifice plates to correct the fuel distribution to within + / - 10%.

Alternatively, in order to limit outage time, RJM can supply balancing dampers for each coal pipe, which facilitates the on-line adjustment of the fuel balance ratio. The balance of fuel and air is confirmed by measuring levels of Carbon in Ash, %O2 and CO across a sampling grid at the boiler outlet.

As part of its coal burner modification technology,  RJM can also supply a Coal Distribution Device (CDD), to eliminate coal "roping" and therefore reduce excessive wear in the burner.

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Fuel Flow balancing probe

This image shows a Pulverised Fuel (PF) Rotorprobe sampler inserted into a PF duct. The rotorprobe takes samples from four different radii at every 22.5 degrees. This testing allows the fuel to be taken iso-kinetically (i.e.at the same velocity as the PF stream) to determine the massflow and product quality. The PF drawn off during this process is collected in the glass container.

Transferring contents from PF sampling test

Transferring contents from PF sampling

The PF is transferred into a sample container, marked up with all relevant test details and sent off to the lab for weighing and a sieve analysis.