„A burner of this type is unique worldwide“, reported Dr. Benedikt Roberg, Director of Hans Hennig GmbH. The Hans Hennig HG-Burner and the Körting CKM-Burner served as a basis. „Both have been utilsed many times already and have distinguished themselves in natural gas operation mode, especially by their low emissions and excellent reliability“, explained Dr. Roberg. The burners were connected with each other in a modular manner. The result was an innovative, up-to-date product made up of components originating from the corporate mother company and the corporate daughter. Since the successful TÜV-Inspection in March 2013 the Körting Group now disposes over a gas burner with 0.15 - 6.5 MW output. So with this, future NOx limit values of 2016 can be observed already.

Up to now enercity operated an auxiliary steam boiler fired with a conventional gas monoblock burner with an output of 6.8 MW in standby operation mode at a power station. Discontinuous heating is required here, as for a domestic heating plant, in order to be able to access a reserve steam amount. The burner switches off if no steam is required. When steam is called for, the burner switches on and produces steam. In the event that only a small amount of steam is required – below the burner’s minimum output, here 1 MW – then the burner switches itself on and off continually. For reasons of safety, however, before each new start-up the complete waste gas path is purged several times with cool fresh air, thereby loosing valuable energy.

To avoid this, a low-load burner keeps the boiler under fire at minimal output when no steam is taken off, so that heat transfer losses are compensated for. „With additional heat demands, the burner increases output and then switches the main burner on. A purging of the waste gas path with fresh air and the heat losses in connection with this are therefore eliminated“, explained Dr. Roberg.

enercity required a control range of 1:68, in this case 0.1 MW up to 6.8 MW output. The answer to this was found very quickly: with high-speed gas burner HG250 Hans Hennig GmbH supplied the geometrical and highly productive low-load burner whereas Körting Hannover AG contributed the appropriate main burner in the form of the well-proved Monoblock burner type CKM63.

„Both burners were built interlocked concentrically with each other. In this way, the corporate ‚mother‘ and ‚daughter’form one unit!“, as Dr. Roberg happily said. The customer too showed himself to be very pleased with the result: „By means of this new and very wide control range we are now in the position of being able to operate our boiler in low-load operation mode for much of the time. “, confirmed Henning Schmeyer, Line Manager of Electro- and Control Technology at enercity. „And that, without having to switch the boiler off from time to time, as was the case earlier. A renewed boiler start-up means always a renewed strain and wear of the material which now is being avoided through the continuous low-load operation mode.“

Henning Schmeyer expressed himself as being very convinced also about the project processing: „As it is here a prototype, diverse optimisation steps were necessary on site at our works in order to finally achieve today’s condition. For this process the collaboration was always conducted in a correct and target-oriented manner.”