Process and apparatus for the production of calcined petroleum coke

Abstract

A process for production of calcined petroleum coke includes combusting, in a fluidized bed reactor, green petroleum coke as a fuel with a substoichiometric amount of oxygen at a temperature of between 900 and 1,400° C. so as to provide a required amount of energy to evaporate volatile matter included in the green petroleum coke. An air-to-fuel ratio in the reactor is less than 1 and retention time is less than 40 minutes. Calcined petroleum coke and flue gas is obtained. The flue gas comprises at least 80 wt-% of the volatile matter contained in the green petroleum coke. The flue gas is at least partially recycled to the reactor as an additional fuel.

1 . A process for production of calcined petroleum coke, the process comprising:
 combusting, in a fluidized bed reactor, green petroleum coke as a fuel with a substoichiometric amount of oxygen at a temperature of between 900 and 1,400° C. so as to provide a required amount of energy to evaporate volatile matter included in the green petroleum coke, wherein an air-to-fuel ratio in the reactor is less than 1 and retention time is less than 40 minutes;   obtaining calcined petroleum coke and flue gas, wherein the flue gas comprises at least 80 wt-% of the volatile matter contained in the green petroleum coke; and   at least partially recycling the flue gas to the reactor as an additional fuel.   
     
     
         2 - 3 . (canceled) 
     
     
         4 . The process according to  claim 1 , wherein the temperature in the reactor is between 900 and 1,250° C. 
     
     
         5 . The process according to  claim 1 , wherein the recycled flue gas is used as fluidizing gas in the reactor. 
     
     
         6 . The process according to  claim 1 , wherein at least a part of the flue gas is passed through a Venturi pre-heater. 
     
     
         7 . The process according to  claim 6 , wherein at least a part of the flue gas is fed from the Venturi pre-heater into a cyclone and/or at least one heat exchanger prior to recycling. 
     
     
         8 . The process according to  claim 1 , wherein pure oxygen, air or another gas containing at least 5 vol-% oxygen is fed into the reactor as a gaseous oxygen source for the substoichiometric combustion. 
     
     
         9 . The process according to  claim 1 , wherein, prior to entering the reactor, a gaseous oxygen source is preheated to a temperature of 400-500° C. and/or the green petroleum coke is preheated to a temperature of 350 to 500° C. 
     
     
         10 . The process according to  claim 9 , wherein the preheating of the gaseous oxygen source and/or the green petroleum coke is performed in a heat exchanger which is fed with at least a part of the flue gas. 
     
     
         11 . The process according to  claim 8 , wherein the gaseous oxygen source and the flue gas are fed separately into the reactor. 
     
     
         12 . An apparatus for production of calcined petroleum coke, the apparatus comprising:
 a fluidized bed reactor of configured to combust green petroleum coke with a substoichiometric amount of oxygen at a temperature of between 900 and 1,400° C. so as to obtain calcined petroleum coke and flue gas, the reactor being configured such that an air-to-fuel ratio in the reactor is less than 1 and retention time is less than 40 minutes;   an inlet conduit configured to feed green petroleum coke into the reactor;   a first outlet conduit configured to remove calcined petroleum coke from the reactor;   a supply conduit configured to introduce a gaseous oxygen source into the reactor;   a second outlet conduit configured to remove the flue gas comprising at least 80 wt-% of the volatile matter contained in the green petroleum coke from the reactor; and   a recycling conduit into the reactor configured to allow at least partial recycling of the flue gas.   
     
     
         13 - 14 . (canceled) 
     
     
         15 . The apparatus according to  claim 12 , wherein the fluidized gas is introduced via a central nozzle.