Case Study 1
German Power plant, 300 MW Unit
2 x Ljungström 2CXS 275/2600
Element depth 2,100mm (700mm x1)
Cleaning Process before using Hydrotech prior to 2001:
Remove entire element layer, top side; transport to ground floor to be washed by conventional
hand-held means. In situclean of middle and cold side elements by conventional hand-held
means. Subsequentreinstatement of hot-endelements once satisfactory clean of remaining
elements has been carried out by labour-intensive wash. Alternatively, in situ clean of entire
preheater matrix from top-side only, incorporating the in-built soot-blowing mechanism.
Total duration of shut-down: 3 weeks
Clean Process since 2001 employing the Hydrotech System automated cleaning:
Day 1:
Arrival on site, preparatory work undertaken (Unit still generating/cooling down)
Day 2: 08:00
Scaffold underside of preheater: Commence internal set-up of cleaning equipment, cold-side
under; Low-pressure, high-bore flush from above. Additional measures: Gas ductwork above
and below preheater matrix to be protected so as to avoid water/moisture ingress past the
dampers above preheater or into the electrostatic precipitators below air preheaters
16:00
Commence HP wash of baskets: 26 hour clean envisaged in two passes.Constant monitoring
of drainage and effluent created during the wash including subsequent introduction of Sodium hydroxide solution as and when necessary
Day 3: 18:00
End wash of baskets; removal of equipment; commence forced-drying of preheater matrix
Unit declared available for generation
Case Study 2
Dutch Power plant, 600 MW Unit
2 x Rothemühle twin-flow Vu 14.5
Primary air element depth 2,200mm (950x2; 300x1)
Secondary air element depth 2650mm (1175x2; 300x1)
Cleaning Process before using Hydrotech prior to 2002:
Remove entire element layer, top side; transport to ground floor to be washed by conventional hand-held means. In situ clean of middle and cold side elements by conventional hand-held means. Subsequent reinstatement of hot-end elements once satisfactory clean of remaining elements has been carried out by labour-intensive wash.
Total duration of shut-down: 3 – 4 weeks
Clean Process since 2002 employing the Hydrotech System automated cleaning:
Day 1:
Arrival on site, preparatory work undertaken (Unit still generating/cooling down)
Day 2:
Commence internal set-up of cleaning equipment; removal of compensator to allow fixture of rotary joint; scaffold underside of preheater; Additional measures: Gas ductwork above and below preheater matrix to be protected so as to avoid water/moisture ingress past the dampers above preheater or into the electrostatic precipitators below air preheaters
Day 3: 08:00
Commence HP wash of baskets: 30 hours envisaged in two passes. Constant monitoring of drainage and effluent created during the wash including subsequent introduction of Sodium hydroxide solution as and when necessary
Day 4: 14:00
End wash of baskets; removal of equipment; reinstatement of compensator; commence forced-drying of preheater matrix
Day 5:
Unit declared available for generation