Method for the catalytic oxidation of a gas, recombination device for carrying out the method, and system which includes the recombination device
In a method for catalytic oxidation of a gas, the outlay required is kept at a low level for reliably treating even relatively large quantities of gas and/or high concentrations of the gas fraction that needs to be treated. For this purpose, a gas stream including the gas being treated is circulated through a reaction zone and a return-flow zone, which is in communication with the inlet and outlet sides of the reaction zone. The circulation of the gas stream can be maintained effectively in the form of a passive system if the gas stream which includes the gas to be treated is guided in the upward direction in the reaction zone and the upward flow is assisted by convection resulting from the heat released during the oxidation reaction. Furthermore, the gas stream is preferably cooled locally in the return-flow zone by spray cooling.
1. A recombination device for catalytically oxidizing a gas, the recombination device comprising:
a reaction zone having an inlet side and an outlet side;
a return-flow zone communicating with said inlet side of said reaction zone and with said outlet side of said reaction zone such that a gas stream can be circulated;
a common housing in which said reaction zone and said return-flow zone are configured; and
a plurality of spray nozzles for receiving a coolant, said plurality of spray nozzles configured in said return-flow zone.
2. The recombination device according to claim 1 , wherein said reaction zone is formed by a stack through which convective flow is possible.
3. The recombination device according to claim 1 , comprising a plurality of catalyst elements configured in said reaction zone.
4. The recombination device according to claim 3 , wherein each one of said plurality of catalyst elements is designed as a catalyst plate having a washcoat surface based on platinum or palladium; and said plurality of catalyst elements are configured at a distance of approximately 0.5 to 2 cm from one another.
5. The recombination device according to claim 1 , comprising an ejector connected upstream of said inlet side of said reaction zone.
6. The recombination device according to claim 1 , in combination with an off-gas system, the recombination device comprising a catalytic further purification stage integrated in said common housing; said catalytic further purification stage having an outlet connected to said off-gas system.
7. The recombination device according to claim 6 , comprising a cooling unit connecting said further purification stage to said off-gas system.
8. The recombination device according to claim 7 , wherein said further purification stage includes a plurality of catalyst plates; said plurality of catalyst plates configured at a distance of approximately 0.2 to 1 cm from one another.
9. The recombination device according to claim 6 , wherein said further purification stage includes a plurality of catalyst plates; said plurality of catalyst plates configured at a distance of approximately 0.2 to 1 cm from one another.
10. The recombination device according to claim 6 , wherein said further purification stage is designed as a stack through which convective flow is possible.
11. A system for catalytically oxidizing a gas, comprising:
the recombination device according to claim 1 ; and
a steam injector unit connected upstream from the recombination device.
12. A system for catalytically oxidizing a gas, comprising:
the recombination device according to claim 1 ; and
an activated-carbon hold-up line connected downstream from the recombination device.
13. The recombination device according to claim 1 , wherein said reaction zone or said return-flow zone is connected to an oxygen feed system.
14. The recombination device according to claim 1 , further comprising a sump pool arranged in a bottom region of the recombination device, said sump pool being provided with a heater device.