Thursday, 15. November 2007

CO2 emissions and consumption of natural gas significantly reduced

Modernization of the central waste air incinerator in Dormagen

(from left to right): Martin Soborka (BIS),
Thomas Leyendecker (BTS)
and Uwe Listner (BIS)

The modernization of the central waste air incinerator (TVA) at the Dormagen Chemical Park, in which Bayer Technology Services (BTS) has played a significant part, is now complete. 14 months after work started on fundamentally revamping the facility, the official starting signal for the start-up of the new TVA has been given.

At the heart of the modernization is the “regenerative thermoreactor”, which recycles the energy of combustion of some 30,000 Nm3/h waste air treated. The objective was to deploy the new incineration technology to reliably meet the threshold values defined by the German “TA-Luft” air pollution control regulations and at the same time to reduce operating costs. The result is that the new system will reduce consumption of natural gas by more than 90 % and release some 11,000 t/a less CO2 into the atmosphere – a significant contribution to climate protection.

An analysis of possible disposal processes headed by BTS led to the selection of the regenerative thermal oxidation (RTO) system as a suitable method of waste air treatment. With this process the energy contained in the waste air is recovered with the aid of a ceramic accumulator. The RTO system deployed comprises three containers with a ceramic honeycomb structure and an afterburner chamber on top. The honeycombs serve as heat storage media that alternately absorb energy from the hot clean gas and release this to the cold crude gas. The RTO system’s high thermal efficiency makes autothermal operation possible at a very low level of waste air feed (1 - 2 g/Nm3) which means that no additional fuel is required for the oxidation process. Heating up of the RTO system and reheating in the case of insufficient waste air feed is effected by a natural gas burner. Below the reaction vessels are several vents to distribute the waste air among the various chambers. The vents control the cyclic switch-over between the heat storage chambers, which alternately have cold waste air and hot clean gas flowing through them, or in some cases are rinsed out with clean gas.

BTS carried out all modifications during ongoing operation. The technically demanding project was completed on schedule.