Reduced puffing needle coke from coal tar distillate

#1. Technical Field

#The present invention relates to needle coke useful for various applications including forming graphite electrodes. More particularly, the present invention relates to a process for producing needle coke exhibiting reduced puffing characteristics from a coal tar distillate starting material. The invention also includes the reduced puffing needle coke.

#2. Background Art

#FIG. 1 is a schematic flow-diagram of the process to produce reduced puffing needle coke from coal tar distillate feedstock.

#Referring now to FIG. 1, coal tar distillate 14 is directed toward the nitrogen removal system 16. In nitrogen removal system 16, the coal tar distillate 14 can be heated to facilitate the removal of nitrogen components during the processing within the nitrogen removal system 16, as well as to melt or dissolve any crystalline particles which may be present in the distillate at room temperature. Specifically, slight heating can be utilized to decrease the viscosity of the coal tar distillate 14 and provide better contact between the distillates and the reactive surfaces within the nitrogen removal system. Alternately, the viscosity of the coal tar distillate can be decreased by mixing with and dilution by a solvent. Treatment of certain coal tar distillate feedstocks may require both dilution with a solvent and heating to bring about the most efficient use of the nitrogen removal system.

#In one embodiment the nitrogen removal system 16 comprises a column loaded with nitrogen removing material. The system may include one or more columns in a parallel arrangement. Multiple columns are ideal so that when one goes off line, nitrogen removal system 16 can still be continuously operated.

#In one alternative, the components of the nitrogen removal system are fixed-bed (static) columns. In these columns the nitrogen-removing material is fixed and the reactor must be taken off-line from coal tar distillate processing to remove or regenerate the nitrogen-removing material. In another alternative, the columns within the nitrogen removal system are moving bed reactors. In moving bed type columns, the unit contains a fluidized bed of nitrogen removing material wherein the material is continuously removed and added to maintain desired activity of the nitrogen removal system.