Yantai Juli Hydrochloric Acid Electrolysis Plant, China
Chinese polyurethane manufacturer Yantai Juli Isocyanate is developing a hydrochloric acid electrolysis plant in Laiyang city in Shandong province in China. The plant will be built in conjunction with the expansion of its toluene diisocyanate (TDI) production line project on the same premises.
The feedstock hydrochloric acid (HCl) will be supplied by the TDI production plant as a by-product, with a production capacity of 100,000t a year.
The electrolysis plant will convert the HCl to pure chlorine and will have a production capacity of 280t a day.
The estimated cost of the TDI production line expansion and the HCl electrolysis plant is €33m. The plant start-up is scheduled for October 2011 and it will be fully operational by the end of 2015.
Yantai Juli Isocyanate background
Yantai Juli Isocyanate was founded in 2001 and began commercial production in 2002. It is located in the Laiyang Economic Development Zone, about 100km from Yantai and Qingdao ports. The site has good infrastructure and transportation facilities. TDI is the main raw material for the polyurethane production.
The company is investing in the expansion of the TDI plant and building an oxygen-depolarised cathode (ODC) device plant for HCl electrolysis. The projects are scheduled for completion in 2011. The investment will help increase Yantai Juli's annual TDI production capacity from 20,000t to 45,000t.
The majority of the funding for the project will be made by Yantai Juli and a small amount of funds will be from banks.
Electrolysis plant technology
The electrolysis plant will be based on ODC technology. The technology was developed and industrialised by Uhde and Uhdenora. Technological development will be undertaken through collaboration of Bayer MaterialScience, Bayer Technology Services and De Nora.
The HCl plant will have four electrolysers with 178 elements each. The plant will use Uhde Electrolyser Type ODH 250 for the HCl electrolysis for chlorine production. The plant will have about 420 pipes. The electrolysers are scheduled to be in operation by the end of 2015.
Oxygen-depolarised cathode technology
The ODC principle is based on a reaction of oxygen with hydrogen ions of HCl at the cathode of cell. The hydrogen ions migrate through the ODC membrane and react with oxygen at the cathode during hydrogen evolution.
The reaction at cathode is power efficient and takes place at lower cell voltage less than the traditional diaphragm electrolysis. The ODC process can save about 30% of the energy.
The reaction at the anode of the cell is the same as in conventional processes. The membrane electrolysis of the ODC technology offers operational and process flexibility at the plant site.
In January 2010, Yantai Juli awarded a contract of approximately €22m for the basic design and engineering, procurement and construction of the HCl electrolysis plant to Uhde.
Under the contract, Uhde will supply major components of the engineering package and the electrolysers and provide the process licence. Uhde will also provide assistance in plant construction and its commissioning.
The Second Designing Institute of Chemical Industry of China will be responsible for the technical design of the project. The contractor for the plant construction is China Chemical Engineering 13th Construction, a member of China National Chemical Engineering.