| 摘要 |
<p>PURPOSE:To save fuel for calcining CaCO3 and to facilitate the calcination by blowing air into a pipe connecting an Na2CO3 recovering boiler to a calciner for calcining CaCO3 with combustion gas sucked from the lower part of the boiler. CONSTITUTION:Waste liquor from an alkali pulping stage is burned in an Na2CO3 recovering boiler 10, and the resulting smelt is allowed to flow in an Na2CO3 dissolving vessel 16 contg. water from the bottom of the boiler 10. CaO is introduced into the vessel 16 from a CaCO3 calciner 23, and a reaction is caused to prepare NaOH as digesting chemicals. The NaOH is introduced into a white liquor tank 19 and fed to a system for circulating pulp digesting chemicals through a pipe 20. A CaCO3 slurry formed in the vessel 16 is predehydrated, fed to the calciner 23, and calcined. Hot combustion gas is sucked into the calciner 23 from the combustion zone of the boiler 10 with a device 27 and utilized to calcine the CaCO3 slurry, and it is fed to a flue 12. When the gas is sucked, preheated air is fed from an air feeding inlet 31 attached to a pipe 22 connecting the boiler 10 to the calciner 23. Combustible gas sucked into the calciner 23 is burned, so the calcination of the CaCO3 is facilitated.</p> |
