Waste Gas Treatment with LARCH (oxidation/pyrolysis) at the Point-Of-Use

DAS  Process Waste Gas Treatment LARCH
Process Waste Gas Treatment with LARCH for LED Processes

LARCH is our latest Point-of-Use waste gas treatment system especially designed for MOCVD processes. It is capable of treating large flows of hydrogen and ammonia as well as small flows of metal-organics and dopants, which are typically found in common LED processes. The treatment combination of oxidation und pyrolysis extends DAS´ technology portfolio in a sustainable way.

Low investment and operating costs, a simple, robust design and low environmental impact (no CO2 emissions, minimum NOx emission) characterise LARCH. The maintenance interval is expected to exceed six months.

LARCH Operating Principle

The system operates in three steps. Firstly, the process waste gases are introduced through a special packed inlet into the decomposition zone. There decomposition of Ammonia (2NH3 à N2 +3H2) takes place. Subsequently the Hydrogen is electrically ignited and oxidised. The waste gases are burned and oxidised within the reactor (2H2 + O2 à 2H2O). Finally the waste gases are cooled (< 60 °C). They can be released into the environment without any further treatment as they meet the strict German standards for air pollution (TA Luft).  

The following equipment options are available for all LARCH systems:

  • Power Supply: 3 x 400 V/50 Hz or 3 x 208 V/60 Hz
  • Process Tool Interface
  • Signal Tower
  • Drip Pan
  • Earthquake Safety Kit
Principle Waste Gas Treatment with LARCH by DAS
Operating Principle of LARCH

Your Advantages

  • No CO2 emissions: no greenhouse gases, low NOx emissions
  • No Wastewater: no trouble with NH4+ wastewater limits
  • Treatment of H2 at the Point-of-Use: Maximum Security regarding H2
  • Simple and robust Design: low investment costs, low CoO, low maintenance
  • Internal Security: H2 dilution in case of fire
  • Option: Cooling with cooling air (no cooling water, heat exchanger)

Technical Data

  • Dimensions (W x D x H):
    1350 mm x 1000 mm x 2000 mm
  • Access to maintenance area on front and back side
  • Gas entry: DN40
  • Gas outlet: DN300 (standard)
  • Exhaust:
    -8 bis -10 hPa, ~ 3000 m3/h, T < 60 °C
  • Heat load from Waste Gas (H2 + NH3): 
    < 100 kW
  • Emissions:
    H2 Exhaust Concentration < 0,1 LEL,      NH3 Exhaust Concentration meet TA-Luft


  • H2 up to 500 slm
  • NH3 up to 200 slm
  • Metal organic precursors and dopants (TMGa, TMIn, ...), PH3, … :          up to 1slm
  • SiH4: up to 0,2 slm
  • N2: up to 300 slm
Looking for Advice?

If you would like to get in contact with us, please use the following e-mail form or simply call us.

Your details
+49 351 40494-400Give us a call! We are looking forward to providing further information on our products for waste gas treatment.