DD-Jet™ - Boiler Cleaning

60°C temperature reduction at boiler outlet. The DD-Jet system applies a unique water based boiler surface cleaning technique which uses very limited water for great effect.

The DD-Jet Cleaning System is an on-line cleaning system for the radiation passes of boilersfound in Waste to Energy incinerators and Biomass combustion plants. The system is installed on more than 40 WtE plants in Europe and ASIA.
The DD-Jet sends 4-6 concentrated water jet beams from the rotating advanced turbine nozzle complex. The DD-Jet nozzle system provides the necessary water amount in concentrated water beams at only 2 bar pressure, enough to secure effective cleaning of the boiler surfaces, without excessive water usage.

The DD-Jet it is a very powerful alternative to conventional so called shower cleaning systems, the DD-Jet system works by sending a precise concentrated water beam at the boilers hot surfaces. The impact of the water on the hot surfaces causes the water to turn into steam. The water to steam expansion provides a pressure wave that is highly efficient to remove the fouling from the fly ash on the boiler surface.

The DD-JET system reduces the flue gas temperature at boiler outlet typically by 60 °C.
The DD-Jet Cleaning System provides a very efficient cleaning effect, >5 meters from the DD-Jet nozzle head.

Why WtE plants choose DD-Jet


more stable operation


increased boiler efficiency


better boiler operation


reduced flue gas temperature

Mobile Unit

Dublix can use a manually operated unit to carry out a DD-Jet test directly at your plant.

The mobile unit weights approximately 40 kg, and is mounted on wheels to allow easy movement from one hole to the next. A typical cleaning sequence lasts 5-10 minutes per hole with 50-60 l/min water consumption.

The following boiler modifications and supply requirements need to be previously done in order to be able to carry out a DD-Jet test:

  • One or several holes (minimum ø 8,5 cm) on the boiler roof to allow access to all the parts of the furnace wall;
  • Connection to water of 2-3 bar on the boiler roof;
  • Connection to power of 380 VAC / 500 Watt on the boiler roof.

If you are interested in running a test at your plant, contact us via the Contact Form.

Mobile DD-Jet unit




Selected References

Returkraft A/S, Norway

• Waste to Energy •


Biostoom, Oostende, 130,000 ton RDF/h

• Waste to Energy •


AffaldPlus+, Næstved, 1*8 ton waste/h and 2*4,5 waste/h

• Waste to Energy •



Complete service solution

Dublix offers a complete service package for DD-Jet systems, including;

  • Day to day service on installed systems and components
  • Onsite inspection and maintenance
  • Annually renewed service contracts

Worry-free operation with a service contract

A service contract for your DD-Jet system includes everything needed to maintain a reliable boiler cleaning solution. A service contract typically includes:

  • Replacement cleaning heads
  • Troubleshooting support

Service contracts can be customized to your individual needs.

Technical Specifications

Cleaning media The DD-Jet system is using normal tap water at a pressure of minimum 1-2 bar.
Low Water consumption The DD-Jet require typically a water flow of less than 50 l/minute

Operation periods
The DD-Jet require 5-10 minutes per cleaning sequence depending on the boiler height.

Power supply

The DD-Jet require 400 VAC/500 Watt
Weight of the total DD-Jet system including water hose and nozzle The DD-Jet has a weight of 250 kg.
Installation The DD-Jet is roof mounted on steel rails for easy movement to new cleaning position.
A full automated system can serve many injection holes as well as more boilers with boiler roof at the same hight.
Installation height The DD-Jet requires only 2 metres free space above boiler roof.
DD-Jet Nozzle head injection hole The DD-Jet requires minimum 10 cm injection holes.

Ready to learn more?

Your boiler, optimized

  • High efficiency with limited water consumption 30-50 l /min
  • Fast installation on existing boilers
  • >50-120 DegC temperature reduction

Let us contact you to discuss how we can help your plant.

Contact me

Provide your contact details and we will get back to you.


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 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.

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.