Innovations In The New MAD Series To Increase Uptime And Reduce Fuel Consumption

Innovative Marine Aggregate Dredge for gravel dredging
Innovative Marine Aggregate Dredge for gravel dredging

This week, there will be a lot of interesting presentations at the CEDA Dredging Days 2019 in Rotterdam1. I would like to draw your attention to one particular presentation that I was involved with at certain moments in the project, though not in writing the paper. Kudos to my colleagues Frank & Frank to write the interesting manuscript2.

The topic of the presentation will be the change of perspective for the concept of marine aggregate dredging. Historically, the marine aggregate dredging takes place relatively close to shore. With the depletion of the deposits and the increase in demand, other locations further out at sea are coming into focus. As Damen, with a heritage in the design of offshore operating vessels, it was a natural choice to cross breed the offshore supply vessels with the marine aggregate dredges. The resulting offspring: the MAD series of hopper dredges3. Frank de Hoogh will elaborate on the seakeeping abilities of this innovative design.

Other dredging related innovations are the suction tube and ancillary equipment, the screening towers and the process sensors. Of those, I have some personal anecdotes on the screening towers and the density sensor. For all other interesting stories, you’ll have to attend the presentation.

The screening towers are fundamental to the efficiency of the process. If the screening is improved, shorter dredge cycles are possible and a better product can be landed onshore. Also, if the requirement for the product change, the screens have to be adapted to the new specifications. Ideally, this changing has to be done at one unloading phase, otherwise you miss a complete dredge cycle. A lot of effort has been done to optimise the design. But the real test was to actually build, modify and test the complete screening tower, before it was even installed on the vessel. So, we had this construction right here at our doorstep for a thorough evaluation.

Screening towers for fit and fat testing at our yard
Screening towers for fit and fat testing at our yard

One other component, that I was even more involved with, was the non-radioactive density sensor. There are regulations in place to phase out nuclear density sensors4 and a lot of alternatives are available. Back in the !VAMOS! project5, we had the opportunity to test a unit of an electro tomography system. The results indicated a good reliability and a worthy replacement for the traditional nuclear sensor6. Because of the tomography picture, there was an additional benefit: we received an early warning on the slurry behaviour. We could actually see when we were too close to the deposition limit in the pipe line. This enabled us to work with higher densities at lower velocities, resulting in better efficiency and less wear. As the rough process conditions in the mining pit were similar to the marine aggregate dredging industry, we proposed to use this on this MAD also. How we further developed and tested this system is for you to hear and see at the presentation.

Testing the non-radioactive density sensor
Testing the non-radioactive density sensor

Due to the physical processes involved in slurry transport, the mixture does not behave like a normal Newtonian fluid. It is some non-linear viscous substance. At high speeds and low concentrations, it is similar to the carrier water. Slowing down, there is a certain critical speed, where there is a minimum hydraulic gradient. At that flow condition, the specific power consumption of moving a cubic meter of soil is the lowest. So, although working at critical speed is dangerous, it has its advantages: low fuel consumption and less wear. Actually seeing the mixture approaching this critical speed from the deposition is an interesting feature of this new density measuring sensor.

Explanation on slurry flow conditions, critical speed and specific power consumption
Explanation on slurry flow conditions, critical speed and specific power consumption

References

  1. CEDA Dredging Days 2019, CEDA
  2. Next generation marine aggregate dredger as platform for innovation and basis for fleet renewal, CEDA
  3. Damen unveils Marine Aggregate Dredger, Damen
  4. Regeling bekendmaking rechtvaardiging gebruik van ioniserende straling, Staatscourant
  5. Project ¡VAMOS! Let’s Go Real!
  6. Real time production efficiency based on combination of non-nuclear density and magnetic flow instrumentation, WEDA

See also

The Real Benefit Of Becoming An Individual Member Of CEDA

Young CEDA pitch talks at the CEDA Dredging Days 2017 (Credit: CEDA)
Young CEDA pitch talks at the CEDA Dredging Days 2017 (Credit: CEDA)

Do you remember the beginning of my website two years ago? The first public posts on this website were about the CEDA Dredging Days 20171. It has been a long time since then. Back then, I couldn’t have guessed what direction this website would take. By now, this is my sixtieth post! Some memorable moment in itself. Still, I would like to do what I intended to do: share knowledge about dredging. And a preview on the next CEDA Dredging Days in Rotterdam2 is a fitting commemoration of all the other posts in between.

Off course, the renowned CEDA Dredging Days are a platform to meet people and exchange knowledge. Especially all the presentations. That everybody has been sweating on writing the manuscript. Reviewed by the scrutiny of the Technical Paper and Program committee3. From personal experience, I can tell you, there are a lot of interesting papers. You’ve had already a teaser on the presentation of Camille Kapela4, about the dredging project in Monaco5.

Camille Kapela at the CEDA Dredging Days 2017 (Credit: CEDA)
Camille Kapela at the CEDA Dredging Days 2017 (Credit: CEDA)

Another I would recommend is the presentation of my colleague Frank de Hoogh about the new MAD gravel hopper dredge6. It is not just another boat, it is a change of concept. And there are so many interesting innovations on this dredge, that it merits its own sneak preview.

Innovative Marine Aggregate Dredge for gravel dredging
Innovative Marine Aggregate Dredge for gravel dredging

But there are more interesting perspectives on the event. In contrast to other commercial conferences on dredging, this is like a gathering of a community. It is a place for all the commissions and working groups within CEDA to present their efforts and show the reports and results of their work. There is a presentation of the Working Group on contract selection7, an update from of the Working Group on soil investigation and an interactive session themed on the recently published book: ‘Dredging for Sustainable Infrastructure’8.

The interactive session at the previous CEDA Dredging Days (Credit: CEDA)
The interactive session at the previous CEDA Dredging Days (Credit: CEDA)

Above all, it is a social event. All the knowledge presented would be worthless, when there is no community that absorbs the produced information. Would discuss about the content, the feasibility and possible applications. And these discussions generate innovative ideas on the new insights from the presentations and meetings.

Sometimes, I am asked: ‘What good is it to be a CEDA member myself? I can get the benefits of the presentations, the reduced price and the drinks, through the membership of my company. Why would I throw out my personal money?’ Well, it is not about all that. It really is about people and building a community. Having a (small) personal investment brings you in the state of mind, that you belong to this wonderful community with its long history in shaping the world. And that is the real benefit of being an individual CEDA member9. With this personal contribution you can take part of shaping the future of the world.

Thursday evening is the big get together of the dredging community; meet you there! (Credit: CEDA)
Thursday evening is the big get together of the dredging community; meet you there! (Credit: CEDA)

References

  1. Countdown to the CEDA Dredging Days 2017, Discover Dredging
  2. CEDA Dredging Days 2019, CEDA
  3. Committees, CEDA
  4. Dredging in Monaco: challenges and solutions, CEDA
  5. CEDA DMC Visits the Anse du Portier Project in Monaco
  6. Next generation marine aggregate dredger as platform for innovation and basis for fleet renewal, CEDA
  7. Effective contract selection: CEDA’s guide to optimised contracting methods, CEDA
  8. Interactive session, CEDA
  9. Why join CEDA?, CEDA

See also