Objective
Demonstration of a newly developed mass flow device (CORIOLIS-METER) for the accurate measuring of the mass flux of coal dust to power station boilers. By of exact metering of the coal dust mass flux improved control of combustion conditions will be possible and thus exact regulation of the coal-air-ratio to each burner separately. By limiting the excess air-ratio it should be possible to reduce heat losses and NOx-emmissions.
The operation of the mass flux meter will be tested in pilot plant scale simulating real power plant conditions and in real power plants.
Long-term-tests shall prove the reliable operation and the accurate measurement.
The demonstration project has shown, that a CORIOLIS-meter can be applied successfully in coal dust fired combustion systems. The reliable on-line measurement of the coal dust mass flow with the accuracy of < 2% has been proved in pilot plant experiments and long term trials in power plants. Even for highly abrasive materials no wearing appeared. Coal dust mass flow rates up to 50 kg/min. had been realised with the CORIOLIS-meter applied. Higher mass flux rates are possible for larger types. In case of contaminated coal dust (plastic pieces, screws, fibers, etc.) a vibrating sieving system can be applied, which was successfully tested in a power plant.
The installation of the CORIOLIS-meter, which is very small in dimensions, is relatively easy. For control purposes of the coriolis-meter only three parameters have to be recorded.
The long term stability of the measurement instrument had been proved in the experimental trials in power plants (total mass 3000 to, operation more than6 months). From the technical point of view the demonstration project was a fully success. It could be shown by means of the exact on-line measurement of coal dust mass flux, that the feeding systems available are not constant in the feeding rates. Beside long term feeding variations strong short time variations occur, which will influence the efficiency of combustion and the production of pollutants.
Future measures for an efficient and low NOx-combustion of coal dust should incorporate measures for improving the short time accuracy of the coal dust feeding. A combination of an improved feeding system with the CORIOLIS-meter will allow an efficient control of coal dust mass flux or of combustion air.
At ATZ-EVUS a CORIOLIS Mass-Flow meter was developed for exact metering of coal dust mass flux in pneumatic transport. The device is able to handle absolute pressure up to l5 bar, so that it is especially fitted for use in pneumatic transport system. The mass flow signal is linear and simple integration versus time gives the total mass in a certain period of time. The metering device was preleminary tested in metallurgical batch-processes where the mass flux of are and coal dust was measured.
In order to demonstrate that the CORIOLIS-Meter is applicable to the harsh environments of power plants the following investigations during the demonstration project are planned:
* test runs of the CORIOLIS-Meter in a pilot plant, simulating the operation modes in power plants: - Coal dust feeding from storage bins (off-line combustion)
- Coal dust feeding directly from the mill (on-line combustion)
- In the pilot plants the CORIOLIS-Meter will be tested in the reliable operation for different operation modes (continuous load; load reversal, emergency Cut off etc.). Special emphasis is given to abbrassive problems and on low pressure separation from pneumatic conveyer lines by means of special constructed cyclons.
* First test runs with simple control systems will prove that mass flux or air flow regulation is possible.
* In order to prove the reliable operation long term stability tests two demonstration are foreseen in power plants in Germany and Portugal. In these investigations emphasis is given to the reliable operation under harsh environmental conditions and possibility of the application of CORIOLIS-Meter in power plants.
Topic(s)
Call for proposal
Data not availableFunding Scheme
DEM - Demonstration contractsCoordinator
92237 Sulzbach-Rosenberg
Germany