Unique test boiler for biofuels

Date: June; 11; 2013 | Author:
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Can we fuel a plant with peanut shells, paper mass or pulp from olive oil production? Will they burn and produce energy? It is now possible to test biomass without risk in a test boiler equivalent to a commercial plant - with a laboratory and expert knowledge into the bargain.

Fossil fuels will be phased out, and wood chips and straw will become scarce, expensive fuels: depending on what part of the world you are in, the focus will be on the bran left over from wheat-based bioethanol production, palm nut fibres from oil production, bagasse from sugar beet or straw left behind in the fields. It's close at hand. It's waste and by-product biomass. But does it burn and produce energy? How about calorific value, fuel property and chemistry?

It's now possible to find the answers to all these questions, unrestricted by the limitations of lab tests or the risks of full-scale trials, but in a test boiler which combines the best of the smallest and the biggest. Aalborg University and Babcock & Wilcox Vølund have built the complete 'little brother' of a commercial combustion plant.

"It's the only one of its kind in Denmark and its size makes it unique. The boiler has all the adjustment mechanisms and measurement devices found in a commercial plant, but on a much smaller scale," says Lars Busch, engineering director at Babcock & Wilcox Vølund, of the boiler, which has a maximum energy input of 400 kW and can handle 100-300 kg an hour, depending on the calorific value of the fuel.

Joint project yields a return

The boiler is financed and owned fifty-fifty by the company and Aalborg University, where it will constitute the core of the university's bioenergy test centre. Jens Bo Holm-Nielsen, head of sector at the Institute for Energy Technology in Esbjerg, is ready to allow the measuring equipment and knowledge to benefit both university students and Babcock & Wilcox Vølund's customers.

"We are prepared to collaborate with the customers and we have the necessary laboratory equipment for the characterisation of biomass, for measuring their calorific value and performing chemical analyses.”

The head of sector explains that collaboration with private companies is a deliberate pedagogical strategy and that the students are trained to work on concrete projects for companies. For this very reason, the test boiler is physically located at Babcock & Wilcox Vølund's workshop. In fact, it is right next door to the senior workshop, so the oldies and youngsters will be able to compare notes.

The collaboration is equally as deliberate on the part of Vølund.

"One essential part of the project is to maintain close contact with technical training courses here in Esbjerg and to raise them to a level where young people choose to stay in the town – perhaps even with us," says Jørgen Hansen, process engineer at Babcock & Wilcox Vølund. Together with Lars Busch and Jens Bo Holm-Nielsen, he is a member of the bioenergy business network in Esbjerg, where the idea of the jointly-owned test boiler arose.

The test boiler was left idle after a Ph. D project. Babcock & Wilcox Vølund had just been given the job of testing waste bran as a fuel by the Belgian bioethanol producer BioWanze. It seemed obvious to perform the trial in a miniature version of a full-scale boiler. The test went extremely well and led ultimately to the delivery of a boiler capable of handling 20 tonnes of raw bran an hour and producing 100 t/h for the Belgian client. The boiler is now in operation: with the necessary follow-up from Babcock & Wilcox Vølund, of course.

Small boiler with a great future

"I have worked with bioenergy all over the world for 25 years and this kind of boiler has a great future. This applies to biorefineries, conversion from fossil fuels to biomass, large-scale biomass exploitation and the industrial combustion of by-products like bagasse, which is the sugar beet fibre left over from the production of bioethanol. The market is global,” says Jens Bo Holm-Nielsen, who is looking forward to starting to use the test boiler after the summer break and talking through the perspectives with students and customers.

The test boiler's potential is also far reaching for Babcock & Wilcox Vølund.

"We are getting more and more involved in the biomass market, an area where the adaptation of plants to specific types of fuel is crucial," says Jørgen Hansen.

Facts about the test boiler

Biomass test boiler, 400 kW maximum-rated energy input, 100-300 kg/hour depending on calorific value.

The boiler pressure component, grate, economiser, air system, control system, etc. are installed and built as they would be in a full-scale commercial plant.

The hot water from the panel walls, grate and economiser are delivered to the Esbjerg district heating system at a temperature of at least 70°C. Under operation, the boiler provides enough heat for 21 detached homes.

Financed equally by Aalborg University and Babcock & Wilcox Vølund.

Originally built for a Ph.D. project at Aalborg University. It has since been moved to Babcock & Wilcox Vølund's workshop, where it was fired up for the first time in March 2013.

This constitutes the core of Aalborg University's bioenergy test centre in Esbjerg, and will be used in the training of engineers in a number of subjects, including 'Energy Technology and 'Electronics and Control Systems' from September 2013.

 

 
The boiler with the control room for testing biomass is loacted at B&W Vølund's workshop. It is right next to the senior workshop, so the seniors can contribute with their knowledge.

 

 
The grate measures 1 m2 and the boiler is 5 metres tall. The flue gas is cleaned in a multi cyclone before being sent to the 17 metre-stack.

 

 
Electrical engineers Jan Bæk and Arne Nielsen from Babcock & Wilcox Vølund can follow the test data from the control room. The fully commercial control and monitoring system is from ABB.

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