CAUSTIC SODA CONCENTRATION ( NaOH CONCENTRATION ) system
Products
The production of Caustic Soda ( NaOH / Sodium Hydroxide ) and Polyvinyl Chloride (PVC) is one of the most important industries.
The Electrolysis System (Electrolyzer / Membrane Cells) produces Caustic Soda and H2, Cl2 from Salt (NaCl) as follows,
NaCl + H2O　→　NaOH + 1/2 H2↑ + 1/2 Cl2↑
The concentration of Caustic Soda (Cell Liquor) is about 32wt% from the Electrolysis System. This cell liquor should be concentrate to 48～50wt% (normal trade quality) by Caustic Soda Concentration System.
We, KIMURA have many experiences about the Caustic Soda Concentration ( NaOH Concentration ) System in the world.
We have installed this system since 1985 in Japan.
Especially, almost all of the Caustic Soda Concentration System in Japan are designed by KIMURA.
When our customers produces the large capacity of the Electrolysis System, we recommend the Triple Effect Type NaOH Concentration System according to consider about save energy.
However, when the capacity of the Electrolysis System is small, we recommend the Double Effect Type NaOH Concentration System according to reduce the cost of the facilities.

NaOH Production Capacity Evaporation Capacity
Double Effect Type 60 ～ 180 Ton/Day (as 100wt%NaOH) 2.8 ～ 8.5 Ton/h
Triple Effect Type 330 ～ 1,050 Ton/Day 15.5 ～ 50 Ton/h

Features
• ・Using accumulated Know-How and technical experience to minimize capital and operation costs.
• ・Maximizing heat recovery from the product and condensate streams to minimize steam consumption.
We, KIMURA design Caustic Soda Concentration System using the Falling Film Evaporators.
The excellent features of the Falling Film Evaporator are as follows,
1. It takes very short time to heat Caustic Soda Solution. The impurities of metal ions in Product Caustic Soda Solution are very low.
2. The heat transfer coefficients are very high value, so we can design to decrease the heating area compare with the competitors.
3. The amount of holding Caustic Soda Solution in this system is very small, so customers can operate easily.
4. The lifetime of this system is very long, over 20 years.
5. We use the Black Teflon gaskets for the Falling Film Evaporators. The lifetime of these gaskets are very long, almost all no maintenance and no leaks.
6. We can achieve the high efficiency for saving energy using the arrangement of heat recovery system based on our experience.

Engineering
We have many experiences to modify the existing Caustic Soda Evaporators, even if the original fabricator is another company.
These revamping projects need the high technology to design the Caustic Soda Concentration System.
The Caustic Soda Solution has severe corrosive action to the metal at high temperature.
Especially, in high temperature zone, we recommend the Nickel for the evaporators.
When the operating temperature is below 90-100 degree C, stainless steel 310S or 304L can be used.
We have many experiences and corrosive data for Caustic Soda Solution, so we can recommend most suitable materials to produce high quality products.
And we can design the KOH Concentration System as same as NaOH Concentration System.
The physical properties of KOH (Potassium Hydroxide) are almost all same as NaOH.
The KOH Solution has severe corrosive action to the metal at high temperature.
So we recommend the Nickel for the KOH Concentration System at high temperature.
Codes & Standards
1.Materials
JIS, ASME, ASTM
2.Japanese Regulations, Laws and Codes
Construction Code of Pressure Vessels (PV-1 / PV-2)
(Ministry of Health, Labor and Welfare)
High Pressure Gas Safety Law (Institution of Safety of High Pressure Gas)
These codes authorize the fabricator to install the equipment in Japan.
3.Design Standards
JIS B 8265 Construction of Pressure Vessel-General Principles (PV-1 / PV-2)
ASME BPVC Sec.VIII Div.1
TEMA Class R, C, B
4.Certificate of Authorization
ASME U Certificate (U Stamp) for BPVC Pressure Vessels
Manufacture License of Special Equipment People’s Republic of China (ML)
Japan Boiler Association (JBA) : Certificate for Exportation

New EPDM Gasket
New EPDM Gasket for Plate Type Heat Exchanger
In the Caustic Soda Concentration System, we design the saving energy system using the Plate Type Heat Exchangers for pre-heating.
These Plate Type Heat Exchangers are used EPDM gaskets for sealing. The lifetime of these EPDM gaskets are only 1 year at high temperature. So customers need to change these EPDM gaskets every year. When these EPDM gaskets receive the damage by heating, caustic soda leakage happen from the gap of sealing.
We, KIMURA propose the New EPDM gaskets as heat resistance type. These New EPDM gaskets are developed by the vendor of Plate Type Heat Exchangers in Japan.
The lifetime of this New EPDM is 2 years at high temperature.
So when the customers use this New EPDM gasket, the customers can decrease the maintenance cost and avoid the disadvantage of stoppage the Electrolysis system.