ADVANCED DESIGN

Custom solutions for each different application, through: 

  • Discretization
  • Continuous redesign
  • CFD simulations: mechanical, combustion, heat transfer, fluid dynamics

COMBUSTION STUDY 

Based on fuel information acquired from the Client and also from our fuels database and experience, we design the combustion chamber.

Using CFD technology and our property in-house combustion model (combustion air, flue gases flow, combustion processes, heat transfer processes, temperature profiles, turbulence, etc.) we obtain the optimum geometry for the furnace and the whole combustion chamber.

FEEDING SYSTEMS: Feeding screws

We develop our feeding screws (based on fuel type, size and flow, among others) with some remarkable features:

  • Progressive step screws: different steps along the biomass path to furnace to avoid jams.
  • Anti-block system based on current consumption control.
  • Screw steps calculated to deliver 20-30% of the MCR fuel at the lowest rpm and to be able to deliver more than 100% fuel when working at max. rpm.
  • The feeding screw is designed to work continuously, without stops.
  • Back-fire detection system and slight inclination to avoid flame return.

FEEDING SYSTEMS: Hydraulic Pusher

We develop our feeding screws (based on fuel type, size and flow, among others) with some remarkable features:

  • Progressive step screws: different steps along the biomass path to furnace to avoid jams.
  • Anti-block system based on current consumption control.
  • Screw steps calculated to deliver 20-30% of the MCR fuel at the lowest rpm and to be able to deliver more than 100% fuel when working at max. rpm.
  • The feeding screw is designed to work continuously, without stops.
  • Back-fire detection system and slight inclination to avoid flame return.

COMBUSTION SYSTEMS: Grate

Heat resistant casting steel: 1.4777 steel that can work up to 1.150ºC, maximizing heat resistance.

Grate’s variable porosity: Two different configurations which differ in its porosity (air-through ratio).

External movement system: Easy maintenance access and costs, less thermal and mechanical stress and longer grate life. This results in a high availability system.

COMBUSTION SYSTEMS: Water cooled

Semi water cooled step grate: Control and flexibility of the combustion in the range of admisible fuels. Increased grate lifespan thanks to water cooling.

Completely water cooled furnace walls: Wide range of fuels admitted (from very dry to very wet) and improved thermal performance. This type of walls also reduce significantly the radiation losses of the boiler.

COMBUSTION SYSTEMS: Combustion air system

The amount of air needed for a complete combustion is supplied by the combustion air fan with its associated ducts, dampers and flow transducers.

The primary air, blowed under the grate, can be divided in different sections depending on the grate length and fuel type. Secondary air is injected in the combustion chamber through dozens of injectors with its position and dimensions based on combustion simulations. Both flows are measured and controlled individually.

That allows us to control effectively the key combustion parameters (3T’s): Temperature, Turbulence and residence Time.

COMBUSTION SYSTEMS: Air preheating

Depending on the application, a combustion air preheating system shall be included. With a flue gases/combustion air heat exchanger the fuel is valorized in a more efficient way and also the global thermal efficiency grows.

COMBUSTION SYSTEMS: Flue gases recirculation

Depending on the application, a part of the flue gases flow is recirculated after the multicyclone to the furnace, with a recirculation fan. This flue gases flow is mixed with combustion air (preheated or not). The amount of gases recirculated varies from 10 to 30% depending on the application.

With this recirculation, three main goals are achieved:

  • Furnace temperature decrease, therefore lower thermal NOx generation.
  • Grate elements lifespan increased: grate elements temperature control when combustion air stops cooling the grate.
  • Increased combustion quality and control.

STEAM AND WATER DRUM

Our three pass fire tube steam boilers, up to a design pressure of 26 bar(g), can be mounted over the furnace (when P < 10 MW) and dissociated of the furnace (P > 10 MW) and are designed to achieve the optimum heat exchanging with the flue gases. 

Our boilers are manufactured under the EU regulations and can be also manufactured under ASME regulations as an option.

CONTROL SYSTEM

Our plant control system is a result of years of development and experience through several different installations, fuels and applications. Nowadays, the control system modulates almost all parameters automatically and adjusts the system according to the boiler pressure (steam applications) or temperature (hot water applications). There are three main PID based control loops:

    • Load
    • Oxygen
    • Vacuum

The control panel is equipped with a PLC and an HMI, although we can also use PCs and SCADA’s in control rooms.

FLUE GASES TREATMENT

Tangencial efficiency: Multicyclones of tangential technology placed at different levels achieve higher particle removal performance than usual systems on the market.

Additional systems: Bag filters, Electrostatic precipitators, All-dry scrubbers, DeNOx systems (SCR, SNCR) and other equipment can be installed to minimize air pollution to near zero values. 

 

PERFORMANCE

The automatic fire tubes cleaning is carried out by means of high pressure air, eliminating fouling and significantly reducing maintenance costs and unavailability.

Additional systems to increase thermal performance can be designed and installed: combustion air preheaters, Economizers.