The improvement of non-slagging cyclone gasifiers/combustors for coal-based solid fuels
This contract has been concerned with the development of coal fired, non-slagging cyclone combustors. To avoid slagging and minimise emissions a cyclone combustor should operate with the first stage fuel rich. The internally generated centrifugal force field suspends the burning coal particles in the near wall region, where they devolatilise and then burn. A unique feature is the retention of ash in the system, typically via two collector pockets. Initial work was involved with an analogue consisting of a 75 kW natural gas fired cyclone combustor seeded with an inert fine material at loadings commensurate with full size units. For a simple vertical unit with one inlet all particles greater than 25-30 micron were retained, together with 30-40% down to 1-3 micron. A new inlet configuration called scroll inlet/vortex weir could retain all particles in the 89-10 micron range. Successful tests on a 400 kW, vertically upwards firing, crushed coal fired unit led to the evolution of a 1.5 MW prototype for kiln firing. Fuel burnouts up to 94% were achieved with ash retention levels up to 80% whilst the underlying NO(x) emissions were only 100 ppm. A very successful inverted, downwards firing unit was also investigated, fired primarily on crushed coal, culminating with a series of trials in which the scroll inlet/vortex weir was incorporated. Fuel burnout levels better than 96% were achieved with ash collection levels of 80-85%. Modelling work included the investigation of a phenomenological model to predict global performance trends. Finally, a finite difference prediction procedure was modified successfully to predict the performance of such units.
Bibliographic Reference: EUR 13869 EN (1992) 209 pp., FS, ECU 16.25
ISBN: ISBN 92-826-3362-4
Record Number: 199210334 / Last updated on: 1994-12-02
Original language: en
Available languages: en