Study on separation the molten mixture of NaOH-Na2CO3 by molten crystallization

Hydrogen production from biomass pyrolysis with molten NaOH had achieved high yield of hydrogen, but the molten mixture of Na₂CO₃ and NaOH was obtained during the process of hydrogen production, since Na₂CO₃ can be acted as a product and NaOH is recycled, Na₂CO₃ and NaOH need to be separated.In this paper, the separation of molten mixture of NaOH and Na₂CO₃ was investigated through molten crystallization. The influences of thermostatic time, depart temperature, temperature controlling way and molar content on the separation results were studyed. The results showed that the suitable thermostatic time was 30 minutes, and temperature directly dropping to desirable temperature was in favor of improving the percentage of NaOH. The suitable separation temperature was impacted by the content of Na₂CO₃. The quality was kept constant when the molar content of Na₂CO₃ is 25%, and the appropriate separation temperature is 370°C,which is higher 80°C than that of the molar content of 10% Na₂CO₃.This article provides some references for separating the residue which is attained in the process of hydrogen production by pyrolysis of biomass in molten NaOH.