Combustion system and heating by infrared radiation and heat recovery for low temperature processes.

The developed technology consists of two main parts; The high energy efficiency self-recuperative self-regenerative burner and the radiation heat transfer unit and load placement. The high energy efficiency self-recuperative self-regenerative burner consists of an integrated ceramic matrix heat recovery system, with the characteristic of being able to work, without making any modifications or adjusts to the burner, at the same time in self-recuperation and self-regeneration modes. Having the heat recovery zone integrated to the burners´ structure self-recuperation and self-regeneration takes place, offering the advantage, regarding the recuperators and regenerators external to the burner, to be compact thus avoiding heat loss through pipes and transitions, in addition to reducing extra costs. Depending on the implemented configuration, self-recuperative or self-regenerative mode, the system´s operation and power may be different. In self-regenerative mode, due to the fact that the two combustion chambers work alternately, that is, first one chamber and afterwards the other, the maximum power is 35 kW. In self-recuperative mode, due to the fact that the two 35 kW chambers each, work simultaneously, the total power is 70 kW.

Self-regenerative operation mode:

  • Used fuel: natural gas.
  • Thermal power: 35 kW on a LHV basis.
  • Tasa de aireación primaria: 1.56.
  • 26.56 kW/m² specific power.
  • 60-second regeneration cycle.
  • Self-recuperative mode operation
  • Used fuel: natural gas.
  • Nominal thermal power 68 kW on a LHV basis.
  • Maximum operation power: 70 kW.
  • Aeration factor regulation range: 1.1, and 1.3.
  • 59.4 kW/m² specific power.

 

The radiation heat transfer unit and the load disposition, consist of silicon carbide tubes joining the burners exhaust. These tubes when being heated by the combustion gases release thermal radiation to the surroundings. To improve the transfer of heat, the silicon carbide tubes are installed in the geometrical focus of metallic circular-parabolic-like shape reflector whose exact detail is part of classified manufacturing practice, so that radiation emitted by the tubes targets the load zone and presents a greater vision factor. The load to be heated in the furnace may be handled as a continuous process or on batch by batch basis.

Benefits and Advantages

The development of the high energy efficiency self-recuperative, self-regenerative burner bears the following technological impacts.

  • The burner, having an integrated heat recovery system for the preheating of combustion air up to temperatures as high as 200 ºC, allows savings in fuel consumption as high as 20%. This also involves reductions as high as 20% of green house effect gas emissions to wit CO2 emissions. 
  • The burner, working by stages, guarantees low polluting substances emissions such as NOx, CO2, unburnt hydrocarbons, particulate matter, carbon monoxide, volatile organic compounds, etc.
  • The burner, using gaseous fuels from fossil sources as natural gas, or from renewable sources as biogas and synthesis gas, guarantees the absence of particulate matter emissions into the environment, as well as lower greenhouse effect emissions such as those caused by CO2.
  • Possible to heat a wide variety of products, since the burners have a wide 5:1 operation range (between 8 kW and 40 kW per burner).
  • The energy efficiencies reached with the furnace oscillate between 1.3 and 2 times the efficiency of the conventional drying by infrared radiation technologies when heat recovery is done in a self-regenerative mode.
  • When heat recovery is done in a self-recuperative way, the increase in efficiency may reach as high as 1.3 times greater. On the other hand, contaminating gas emissions are low. Additionally, the furnace is flexible given the dual heat recovery mode allowing self-regenerative heat exchange or self-recuperative heat exchange at slight adjustments in the air connections.