Influence of coal tar evaporation conditions on product quality and yields

Journal Article · Thu Jan 01 04:00:00 EST 1976 · Coke Chem., USSR (Engl. Transl.); (United States)

OSTI ID:6773136

Bondarenko, L M; Nepomnyashchaya, A S; Kovalev, E T; Lisachenko, A S; Datsenko, L I

Coaltar distillation is now mainly carried out in continuous flowsheets with one, two, or more evaporation stages. The choice of evaporation methods is usually determined by the number and variety of products it is required to make. Single-stage evaporation, for instance, produces a higher proportion of high-boiling fractions than evaporation in two or more stages. In other countries, market requirements basically determine the choice between the various methods of evaporation under atmospheric pressure or in vacuo. Tar distillers in the Soviet Union operate a standard flowsheet, incorporating single-stage evaporation under atmospheric pressure. The apparatus requirements are straightforward, but the technical scope is limited; the naphthalene oil only contains 80-83 percent of available naphthalene, the yield of anthracene fractions is high (23-27 percent), and the pitch yield is correspondingly reduced. Growing commercial demand for these products now requires improvements beyond the scope of single-stage evaporation flowsheets. It is possible to raise the naphthalene recovery in the distillation stage to 90 percent without modifying the flowsheet, by supplying additional heat to the columns. However, this recovery rate is also achieved in two-stage evaporation flowsheets, and it can be shown on theoretical grounds that the pitch yield in this case will be higher than in the single-stage evaporation process. Comparative tests on the single- and two-stage evaporation of typical coaltar samples from Southern coking plants have now provided more information on the effects of evaporation conditions on the yields and qualities of the pitch and distillates.

• OSTI ID: 6773136
• Journal Information: Coke Chem., USSR (Engl. Transl.); (United States), Journal Name: Coke Chem., USSR (Engl. Transl.); (United States) Vol. 7; ISSN COKCA
• Country of Publication: United States
• Language: English

Related Subjects

01 COAL, LIGNITE, AND PEAT
010500* -- Coal
Lignite
& Peat-- Products & By-Products
AROMATICS
COAL TAR
CONDENSED AROMATICS
EVAPORATION
HYDROCARBONS
NAPHTHALENE
ORGANIC COMPOUNDS
OTHER ORGANIC COMPOUNDS
PHASE TRANSFORMATIONS
PITCHES
PROCESSING
RECOVERY
TAR
YIELDS