Page 235 - Chemical and process design handbook

Speight_Part II_C 11/7/01 3:08 PM Page 2.175

COAL CHEMICALS 2.175

Starting Initial Secondary Tertiary
material products products products
Coal Gas Fuel gas
Sulfur
Light oil Naphtha Cyclopentadiene
Indene
Benzol Benzene
Toluols Toluene
Xylols o-xylene
m-xylene
p-xylene
Coal tar Pitch
Tar Fluorene
Diphenylene oxide
Acenaphthene
Methyl-naphthalenes
Creosote
Tar acids Phenol
o-cresol
m-cresol
p-cresol
3, 5-xylenol
Tar bases Pyridine
Alpha-picoline
Beta-picoline
Gamma-picoline
2, 6-lutidine
Quinoline
Naphthalene
Crude anthracene Anthracene
Phenanthrene
Carbazole
Coke Carbon
FIGURE 1 Selected chemicals from coal.

The tar separated from the collecting main and the tar extractors or
electrostatic precipitators is settled from ammonia liquor, together with
light oil. The tar is filtered and pumped through the reflux vapor-tar heat
exchanger and economizer, pitch-tar heat exchanger into the top of the
lower third of the distillation column and out at the bottom, to the circu-
lating pumps and into the pipe still where the crude tar joins 4 to 5 vol-
umes of the circulating pitch, and on finally to near the top of the
distillation column.