Energnist (L90), Esbjerg, Denmark

Waste-to-energy plant, CPH

At the beginning of 2001 we signed a contract with L90 (now Energnist) for a large new waste-to-energy plant in the city of Esbjerg. L90 is a union of 35 municipalities with more than 600,000 inhabitants in the mid Jutland area and was formed with the purpose of owning and operating the new plant.

Thermal efficiency of 89%

The fuel is domestic and industrial waste, and the plant has a design capacity of 24 t/h at a heat value of 11 MJ/kg, corresponding to 180,000 t/year. This is one of the largest plants in Denmark.

The plant features advanced waste combustion and boiler technology as well as emissions to air and water. The plant is a combined heat and power plant and the overall thermal efficiency is 89%.

L90 Esbjerg waste-to-energy plant

Our scope of supply

Our scope includes a complete waste-to-energy facility: combustion equipment with waste crane, feed chute, feed grate, and five-section combustion grate, combustion air system, auxiliary burners, ash conveyors for slag and fly ash from the boiler hoppers, feed water pumps with controls. We have supplied a steam boiler with boiler drum, vertical furnace with empty passes (pendent structure) followed by economiser and superheater sections made of vertical tubes (standing structure) with cleaning arrangements. Pressurized air and SNCR system.
Complete control equipment for the whole waste-to-energy plant excl. software for turbine, flue gas cleaning, etc.
The boiler generates high-pressure steam for a turbine of 16.5 MWe, and the remaining heat is utilised for district heating in the local district heating network.

Water-cooled wear zones, Inconel® cladded boiler, and an advanced combustion control system

The furnace is provided with water-cooled wear zone sections at both sides. L90 was the first plant to be installed with our water-cooled wears zone. The setup of the wear zones is both indirectly connected and externally connected:

  • Indirectly connected: the heat absorption is used for air or condensation preheater so that the plant’s efficiency is increased. The wear zone is executed in standard black boiler pipe.
  • Externally connected: the heat absorption is used for district heating.

Furthermore, the furnace and the first boiler pass are cladded with Inconel®  -a very wear and heat-resistant alloy - welded directly onto the boiler tubes. Thus the need for refractory, which requires annual inspection and frequent repairs, is eliminated.

Advanced Combustion Control (ACC) technology with camera monitoring of the combustion is installed. This makes it possible to control the air supply to the grate in a network, which ensures homogenous combustion through-out the grate.

Plant design data

Process parameters Guaranteed values*
Nominal waste capacity 24.0 t/h at 11,0 MJ/kg
Max. continuous capacity 26.4 t/h at 10,5 MJ/kg
Steam data  42 bar, 400oC
Steam generation, nominal  25.13 kg/s
Steam generation, max. cont.  26.37 kg/s
Feed water temperature  130oC
Electric output  16.5 MWe
District heating output  46 MW
Flue gas guarantees out of boiler:
Dust  4.0 g/Nm3
CO  50 mg/Nm3
NOx  200 mg/Nm3
NH3 10 mg/Nm3
Dioxin  5 ng/Nm3

All values refer to 11% O2 dry gas.

Flue gas values refer to daily averages. For dioxin 6-8 hours.

The values are before flue gas cleaning.
The plant limit values complies with the EU directive on waste incineration. Naturally the plant is equipped with a modern flue gas cleaning system.