Polytechnik

For this plant, Polytechnik supplied not only the combustion chamber and the components for heating the reactor, but also the boiler, the hot water system and the necessary controls for these components. The energy obtained from the combustion of synthesis gas is used to generate hot water, but also for indirect heating of the reactor. In addition to ensuring maximum energy utilization, waste heat is also used to increase efficiency. By returning the flue gas (energy obtained from the combustion of synthesis gas) to the system, a controlled environment for biomass processing is created, potential contamination is prevented and uniform heating is ensured.

Combustion chamber:
The combustion chamber is designed as a horizontal, adiabatic gas combustion chamber for the oxidation of synthesis gas (also known as torr gas in this case) and complete combustion. The torr gas is burned in two specially developed torr gas burners. An oil burner is used for ignition and support at low loads.
The torr gas piping system consists of four pipes: two pipes with injector burners convey the torr gas from the reactor to the combustion chamber and regulate the pressure in the reactor; two pipes carry the torr gas from the reactor to the emergency cyclone, where the torr gas is cooled and then discharged into the chimney by means of the natural draft caused by the chimney’s height.

Boiler:
The flue gas from the combustion chamber is divided into two streams: One stream is used to heat the reactor, the other to generate hot water. The flue gas circulates between the reactor and the combustion chamber. To maintain the reactor temperature, ‘fresh’ hot flue gas from the torr gas combustion chamber is continuously mixed into this cycle.
The remaining flue gas enters the hot water boiler. The hot water boiler is designed as a fire-tube boiler. After the boiler, the flue gas flows through the flue gas condensation system and from there via the induced draught fan to the chimney.

Hot water system:
The hot water boiler circuit is a closed circuit in which the hot water is pumped through a heat exchanger. The secondary side of this water heat exchanger is the glycol water system for heating a belt dryer to dry the biomass before it enters the reactor. Excess heat can be fed into the local district heating network.

DCS system:
Hardware: Central control cabinet and I/O cabinets, Software: The application software includes system programming and configuration such as: logic application (start/stop sequences, interlock conditions, etc.), alarm configuration, trend configuration, interface to other systems (data exchange with third-party systems), operator displays, interlock indicators (visualization of interlock conditions on the HMI screens).