METHOD FOR CONTROLLING CARBON BLACK FURNACES

摘要

In a carbon black furnace of the type in which fuel, hydrocarbon make stock and air are reacted, the supply of air being insufficient for complete combustion, samples of the combustion gases are taken continuously and their thermal conductivity compared with a reference nitrogen gas and any variation from the correct setting causes a signal to be transmitted to a valve to maintain the correct ratio of fuel &c. for producing carbon black of the desired properties. In one embodiment, Fig. 1, a combustion chamber 13 having gas burners 20, a feed pipe 21 for the hydrocarbon make stock and an air supply 25 to a plenum 19 is arranged above a reaction chamber 14 from which the carbon black passes via a conduit 15 to a collection system. A manually operated valve 27 controls the air supply and a valve 31 in a by-pass 28 is controlled by the signal dependent upon changes in the thermal conductivity of the gas sample. A sampling probe 32 extends into the chamber 14 and a sample of combustion gas passes through a cyclone separator 45, a filter 49 to a gas flow measuring device 52 and then to the thermal conductivity cell 55 connected to a D.C. source 56. Changes in an electric signal produced in the cell 55 pass to a controller 69 which produces a pneumatic signal in line 71 whereby the valve 31 is operated. The valve 31 may control the total air feed if desired or alternatively may control a by-pass in the oil supply or may control the total oil supply. In a further embodiment the valve 31 may control the gas supply by being positioned in a by-pass line or in the main supply line. The control can be applied to any two of the three components fed to the furnace.