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 12 m x 12 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 the outlet flue gas temperature effectively low.

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.

What are the DD-JET cleaning effects on boiler outlet fluegas temperature?
The soft and careful cleaning effect of a single boiler pass cleaning reduces the boiler outlet temperature in the range of 80-120°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 nozzel head for the in the DD-JET system?
A typical lifetime of the water hoses, also for the parts entering the inside of the boiler, and the nozzle head is longer than one year.

Where are the DD-JET installed?
The DD-Jet has been delivered to a number of very demanding WtE plants in Europe (view the reference list).