REPORT
A modern coal preparation plant has a
complex and ramified flowsheet. There are several flow streams circulating in
the plant's circuit network. The streams are responsible for slime accumulation
in recirculating plant water. Water fails to wash the coal because its density
and viscosity increase. Therefore slime recovery is common and an actual problem.
There are several units to recover the slimes. In addition, the process is a
function of circuit design, stream directions, retention time and distribution.
Hence a modeling method is necessary to investigate the slime accumulation.
Unfortunately there is no effective method to tackle the problem among recent
techniques. On the other hand, some numerical methods are widely adapted in
recording information upon which future action can be based. One of them is an
extended balance method'. The method is performed through an analysis of
preparation process's network. The authors make use a similar method for
assessment of slimes accumulation.
An elementary slime accumulation model has been used in
the development. A computer program has been made to produce numerical
simulation. The program is based on the model mentioned. A set of programs has
been made to make of slime accumulation modeling comfortable and efficient.
There are three programs. The first is the RECORD-KEEPER. One registers names of
plants and numbers of flowsheets. Every flowsheet has a file with a unique name
to input initial data, namely pairs of jointed network nodes and the
distribution coefficients. The second program is the SLIME to simulate the slime
accumulation. The program initializes the RECORD-KEEPER to build a menu of plant
names and flowsheet lists. Then a user chooses a relevant plant and the
flowsheet and the program opens a corresponding initial data file and inputs the
data. The user may input number of iteration (namely number of water circulation
cycles) independently. After revealing of return nodes the program begins to
calculate the slime accumulation.
Any number of plants and flowsheets may be simulated, and
after this analysis of the results may be produced independently with the PLOT
program. The PLOT initializes the RECORD-KEEPER and by the menu, gives
possibility for the user to choose arbitrary numbers of nodes from any
flowsheets of any plants. This feature is very useful because the program
enables to compare the operation of different flowsheets and different plants.