That’s the project Prof. Dr. Le Viet Luong and his colleagues at Maritime University’s Faculty of Shipbuilding have studied strenuously since 2008. The project has been successful and applied to shipbuilding in Vietnam, which contributes much to reduce environment pollution, fuel cost and waste treatment.  

Energy Conservation Office had a short conversation with Prof. Dr. Le Viet Luong (head of the project) to help readers understand more about its benefits as well as applications. 

Q: Professor, congratulations on your success of the project “utilize heat of exhaust from vessel motor to save fuel”. Would you please tell us reasons for choosing this project? 

The shipbuilding industry in Vietnam is growing strongly with the ships as large as 50,000-100,000 tons. These ships, mainly diesel driven, have great capacity of tens of thousands HP. As a result, the amount of exhaust from these engines is large with high pressure of about 0,35Mpa and temperature as hot as 400oC. The great discharged energy accounts for 20-25% of the heat generated in the combustion chamber. If we can thoroughly utilize this source of energy, we can save a lot of fuel and increase the efficiency of vessel engines.

With this in mind, I myself have been nurturing the idea of successfully manufacturing a system which can take advantage of that potential source of energy. In 2008, under the National Program on Energy Efficiency and Conservation (VNEEP), the Ministry of Transport’s Department of Environment assigned the Maritime University to implement the project “Test manufacture of modular steam boiler which utilizes the heat of exhaust from vessel diesel motor to save fuel.” This is the initial project for our later studies to thoroughly utilize the heat of exhaust from vessel motor. 

Q: What are the benefits of this utilization?  

The exhaust-heat-utilizing boiler not only brings about great economic benefits by reducing input cost, money to treat waste and environment pollution but also provides saturated steam to warm up heavy oil, distil fresh water, separate water oil, blow valve, to cook and serve the living of the crew. Some big and modern vessels use the superheated steam from the boiler to operate generators, air conditioners and refrigerators. Using the exhaust this way can also help increase shipping efficiency, feasibility of domesticalization of shipbuilding industry and research-manufacture competence of our researchers. 

Q: This type of boiler has been used for a long time by many countries in the world, why don’t we apply that technology directly? 

All the boilers used in the vessels of Vietnam are designed and manufactured in developed countries. However, we shouldn’t imitate mechanically. The boilers should be improved and manufactured so that they are reliable and economical. Moreover, with the development of our industries in general and the shipbuilding industry in particular, we can design and manufacture our own type of boiler.

Structure and junctions between parts of modular steam boiler

Our boiler has the module-type structure which is different from the conventional boiler. The advantages of this type of boiler are: low manufacturing cost, easy to maintain, repair, manufacture, install, operate and replace.  This has been recognized by appraisal agencies. Moreover, related agencies have approved the installation and operation of our boiler. 

Q: What products has your team designed, manufactured and applied? 

After finishing the project “Test manufacture of modular steam boiler which utilizes the heat of exhaust from vessel diesel motor to save fuel”, in 2009, we continued to implement the second project “Pilot application of exhaust-heat-utilizing boiler in vessels”.

3D design of exhaust-heat boiler and energy-saving water boiler

With the success of those two projects, we have designed and manufactured the modular exhaust-heat-utilizing boiler with design pressure of 10kG/m2, working pressure of 6kG/m2, heat transfer surface area of the boiler 13,2 m2, the area of water heater  6,33 m2. All the designs have been registered at Vietnam Register. 

Q: How has that project been applied? 

According to preliminary calculations, the payback period of this project is about 4 months. Therefore, it will bring great economic benefits to vessel owners. However, the installation depends on many factors, the most important of those is the approval of the owners. For the past 2 years, the number of new vessels has been decreased significantly due to economic crisis, owners have been very hesitant in investment. Now, we are still contacting vessels operating companies to apply the result of the project massively.

The project also contributes to the undergraduate and postgraduate training. 

Q: What is your plan in the coming time to develop the project? 

We are now studying the project: the creation of auxiliary boiler to maximize the efficiency of exhaust-heat-utilizing boiler. The success of this project will encourage us to continue the project: Test burning discharged oil (sludge oil, dirty oil, lubricant oil and used cooking oil) by steam boiler to reduce environment pollution and save fuel.

We need supports from the VNEEP, the Department of Environment (Ministry of Transportation), and the university. The applicability of the projects depends much on shipbuilding companies. So the most important support is financial assistance for vessel owners to invest more in exhaust-heat-utilizing boilers. 

Thank you!

Hung Linh