Aerovit A/S - Aerovit Case story

Grästorp, SE

Co-owned by Lantmännen Agroenergi AB and the municipality of Grästorp, Sweden.

Fuel
Wood chip and Salix.

Boiler
Danstoker 3.5 MW FVB – installed 2002.

Soot-blower
The boiler was delivered with a competeting

soot-blowing system at the top of the boiler.

9 pcs. valves on 1st stroke countercurrent
5 pcs. valves on 2nd stroke wake
7 pcs. valves on 3rd stroke countercurrent.

Efficiency
Mechanical cleaning seems to be necessary several times per month – the pipes are not kept clean.

Initiative

It was decided to replace the soot-blowing system on the 1st stroke.

AEROVIT soot-blowers on a new boiler door were delivered February 2003.

AEROVIT on the first stroke

Result
Mechanical cleaning only necessary twice a year.

The pipes in 1st stroke are now kept clean.

The pipes in 2nd stroke are now kept fairly clean.

The pipes in 3rd stroke are not kept clean.

Future
If the remaining soot-blowing system is replaced with AEROVIT valves, it is to be expected that there will be a need for mechanical cleaning only once every 2 or 3 year.

Service carried out on all valves after 4 years in operation.

The soot-blowing system – without cooling – on 2nd and 3rd stroke shows dysfunction and flow of compressed air.

All 12 valve diaphragms were burned or melted, cracked and rigid – clearly affected

by the heat from the boiler’s turn box. All diaphragms had to be replaced.

Corrosion in the shot tube of the valves – obviously affected by corrosive flue gas. The shot tube is almost sooted up in consequence of dysfunction.

Aerovit A/S' AEROVIT valve system – with cooling – on 1st stroke has faultless function.

All 9 valves and valve diaphragm are in good condition and require no replacement.

Clear result of AEROVIT's patented system with cooling air.