A research group from the Shenzhen Institutes of Advanced Technology (SIAT) of the Chinese Academy of Sciences, along with Guangzhou Institute of Advanced Technology, an affiliated institute of SIAT, proposed a novel supercritical water oxidation (SCWO) system with an inverse cool-wall reactor to realize energy self-sufficiency.  

SCWO is a powerful green technology to treat hazardous wastewaters. However, SCWO treatments at pilot plant scale of real wastewaters are much less extensive in literature. Furthermore, due to the increasing energy demand, the industrial application of its process has 3 main problem: corrosion, salt plugging and high treatment cost. 

Transpiring and cooled-wall reactors are widely used to overcome the corrosion and salt plugging problems in the SCWO process. But the energy consumption will significantly increase because the energy grade of the reactor effluent is decreased. 

The study claimed that with the improved cool-wall reactor and corresponding system, the energy consumption could be greatly reduced because the energy recovered from the reactor effluent was upgraded for power generation. 

The SCWO system with an inverse cool-wall reactor, in some ways parallels the countercurrent heat exchange, was simulated using Aspen Plus 8.2. Exergy analysis was also conducted to compare the results of the proposed system with that of the previous SCWO system with a transpiring wall reactor. 

The treatment cost has reduced by nearly 30% compared with the present system. This novel system has a large market potential. 

"The increase of fluid temperature or feed concentration contributes to achieve energy self-efficiency” said Dr. ZHANG Fengming. “High reaction temperature may be presents at high feed concentration, but this issue can be easily solved by increase heat transfer area.” 

The study was published in Applied Thermal Engineering. 

Fig.1 The novel supercritical water oxidation system with an inverse cool-wall reactor (Image by Dr. ZHANG Fengming) 

 Fig.2 Energy flow diagrams of the SCWO system (Dr. ZHANG Fengming) 

Media Contact:
ZHANG Xiaomin
Email: xm.zhang@siat.ac.cn