DD-JET FAQ

How large an area can be cleaned by the DD-JET system?
Typical surface size of cleaning in boiler is 22 m x 10 m x 10 m through one boiler roof hole.

How often shall the DD-JET system operate in order to keep the boiler outlet flue gas temperature effectively low?
A typical operating sequence of less than twice per week per cleaning hole is necessary in order to keep theoutlet flue gas temperature effectively low.

DD-Jet Performance Como

DD-Jet Performance Como

Temperature trend curves from a DD-Jet system installation on an Italian WtE boiler.
The  temperature shown is flue gas temperature at the entrance to the super heator banks.
The shown trend compare the situation before and after the DD-Jet system was installed it indicates improved flue gas temperauture control withou the need for explosion cleaning and no plant cleaning stops for 4 months.

Is special cooling needed?
No special cooling required; the water hose and the nozzle is cooled by the cleaning media only (water).

Are there any cleaning residuals?
The cleaning water is evaporated immediately.
The debris partly flies to the flue gas cleaning and dust filters; other parts fall down and are treated as boiler ash.

What happens if the water pressure is too low?
The cleaning process shall not be initiated or in case of low pressure during cleaning, a fast extraction procedure is initiated.

Can the DD-JET system also clean the boiler roof?
Yes the system is also able to clean the roof section; the choice of nozzle type and number is important.

Can the DD-JET system operate during full load of the plant?
Yes the DD-JET system can operate during full load, however other restriction such as the capacity of the flue gas cleaning system, draft fans etc. might restrict the amount of water injected into the boiler passes.

Can the DD-JET system operate through more boiler top holes?
Yes the DD-JET system can operate through more holes in the boiler roof in order to clean different compartments in the boiler. An automatic motion control providing the movement from hole to hole can be provided.
 
Can one DD-JET system serve more boilers?
Yes one DD-JET system can serve more boilers. A unique curved rail system can be provided, the system is equipped with an efficient horizontal motor controlled movement and positioning system.
 
What are the DD-JET cleaning effects on boiler outlet flue gas temperature?
The boiler outlet temperature from one cleaning circle is in the range of a delta temp of 60-120°C depending on the level of fouling prior to the cleaning sequence.
 
Does the DD-JET require special tuning and adjustment after the installation?
No special adjustment is required. The system is tested and is put online in full operation during a period of 2-3 days on site and do normally not require any modification afterwards.
 
What is the lifetime of the water hoses and the DD-Jet nozzle head?
A typical lifetime of the water hose and the DD-Jet Nozzle are typically much more than 200-300 cleaning cycles. 
 
Where are the DD-JET installed?
The DD-Jet Nozzle head is also installed on equipment delivered by others, this has been initiated due to inefficient cleaning provided by the original supplied system.
Please view the reference list.