HGP direct-fired air heater

In the HGP, clean air from the supply fan sweeps turbulently over baffles and guides on the outside of the combustion chamber, cooling the chamber while it warms up itself. At the chamber outlet it mixes with the flame and flue gases and goes straight to the process as hot gas. The heater is non-pressurised and can be built horizontally or vertically. TSB supplies the HGP for diesel, fuel oil, natural gas, LPG, LNG or biogas, with a heat output of up to 21 000 kW (18 000 000 kcal/h) and gas temperatures of up to 1200 °C.

Burner and driven clean-air fan work together under PID control: modulation sets the heat input over a range of up to 20:1 and holds the process air outlet temperature fully proportional. Heating begins 10–15 seconds after start-up, and since no liquid carries the heat, there is no water treatment, waste liquid, freezing or leakage to deal with. The heater can sit upstream or downstream of the process air fan under positive or negative pressure, and its generous combustion chamber suits heavy oils. With clean combustion, NOx stays below 70 mg/Nm³ on gas and below 150 mg/Nm³ on liquid fuel; with a suitable burner it can fire up to 100 % hydrogen.

The front door has three insulation layers — Hycast SS alumina-enriched refractory concrete, ceramic fibre blanket and ceramic paper — keeping it safe to touch. The combustion chamber is AISI310S and AISI253 high-temperature stainless sheet, the shell P355GH boiler plate or AISI304 stainless sheet, and the outer wall carries 100 mm of high-density insulation. Where needed, cleaning and inspection doors, condensate drains and water-resistant gaskets are fitted. The PLC watches the air flow pressure switch, outlet temperature protection and surface temperatures and shares data via Modbus, Modbus TCP/IP or Profinet. Design follows AD 2000 and ASME Section VIII Div. 1.