Precipitation of sodium sulfate and sodium carbonate during supercritical water oxidation/gasification of ethanol.
- Resource Type
- Article
- Authors
- Chen, Zhong; Zheng, Zhijian; He, Chunlan; Chen, Hongzhen; Yang, Mingjun; Xu, Yuanjian
- Source
- Journal of Supercritical Fluids. Feb2022, Vol. 181, pN.PAG-N.PAG. 1p.
- Subject
- *SUPERCRITICAL water
*SODIUM carbonate
*OXIDATION of water
*WASTE treatment
*SALINE waters
*ETHANOL
*SODIUM sulfate
- Language
- ISSN
- 0896-8446
Reactor plugging induced by salt precipitation in supercritical water (SCW) is a major problem during the hydrothermal treatment of hypersaline waste. Considering that current investigations have focused strictly on pure water systems, a continuous tube reactor was designed herein to study the precipitation of Na 2 SO 4 and Na 2 CO 3 in a complex SCW environment, which was generated using C 2 H 5 OH and H 2 O 2 in order to reproduce real SCW conditions. Results indicate that salt precipitation was accelerated in the presence of C 2 H 5 OH and H 2 O 2. The passage rate was only 87% for Na 2 SO 4 and 43% for Na 2 CO 3 in an aqueous solution of 0.1 wt% C 2 H 5 OH and 0.5 times of H 2 O 2 , compared to the solubility of these salts in pure water at 385 °C and 25 MPa. Organics and gases reduce the fluid density and further aggravate salt precipitation. Salt precipitation occurred mainly in the area around gas inlet and mixer in a real SCW process. [Display omitted] • Organics and gases aggravate salt precipitation in supercritical water (SCW). • Precipitation arises mainly from density drop caused by organics and gases. • Na 2 CO 3 precipitates more easily than Na 2 SO 4 in complex SCW environment. • Salt-scales are mainly formed around inlet and mixer in real SCW process. [ABSTRACT FROM AUTHOR]