Ion Exchange System 1

Automatic Multi-unit Continuous Ion Exchange System
1     Application
The multi-unit continuous ion exchange system with array valves is the most representative product of our company, and more than 30 sets have been using in many industries since 2016.
1)  Water treatment
Ion exchange system is in great demand in the field of water treatment, mainly used for the removal of various anions and cations in water.
2)  Food industry
Ion exchange system can be used in the industrial production of sugar, MSG, wine refining, biological products and so on. For example, in the manufacturing process of glucose,starch milk needs to be treated by ion exchange system after liquefaction,saccharification, deslagging and decolorization to obtain purity.
3)  Petrochemical industry
In organic synthesis,acid and base are often used as catalysts for esterification, hydrolysis,transesterification, hydration and other reactions. Ion exchange resin has more advantages instead of inorganic acid and base. First, resin can be used repeatedly. Second, the product is easy to separate. Third, the reactor will not be corroded. Fourth,Itis environmentally-friendly. Last but not least, the reaction is easy to control.
4)  Environmental protection
Many aqueous or non-aqueous solutions contain toxic ions or non-ionic substances, which can be recycled by ion-exchange systems, such as removing metal ions from electroplating wastes and recovering useful substances from film production wastes.
5)  Other
The ion-exchange system can separate, concentrate and purify uranium from depleted uranium. What’s more, it is used to extract rare earth elements and precious metals.
At present, the multi-unit continuous ion exchange system with array valves is mainly used for starch sugar production,and has become necessary. But we have to improve the system in order to gain market share in other areas.

2     Structure
The multi-unit continuous ion exchange system with array valves consists of a number of ion exchange columns whose structure are simple (Fig 2-1 and 2-2), and its functions depending on the type of resin being filled inside.

                                                

           FIG. 2-1 Elevation view                                                               FIG. 2-2 Cutaway view
Ion exchange is used for deashing and discoloration or adsorption in starch sugar and fermentation industry, has been irreplaceable of purification processes. Traditional ion exchange system consumes a large amount of chemicals and deionized water, the resulting waste water is difficult to treat. By contrast, the multi-unit continuous ion exchange system with array valves can better meet the market demand.

Table 2-1 The development process of ion exchange technology and equipment 

 
3     How the multi units system appears to work

The following is the process of fixed bed in ion exchange. Fig 3-1 is a diagram of the ion exchange process in a typical fixed bed.

Fig 3-1 A schematic diagram of the ion exchange process in a typical fixed bed.

In order to meet the need of certain production, the resin column must be large enough. After using the resin to treat with materials for a period of time, the resin bed falls naturally into three parts, respectively is a saturation area, a treatment area and a  fresh resin area. The treatment area declines constantly with the run time. The resin column won’t desorb and regenerate until the bottom of the resin bed turns to a treatment area and the discharge is close to standard limit. It’s obvious that there are some problems in the fixed bed ion exchange process.

At the beginning, the treatment capacity of fresh resin at the bottom of column is wasteful.

In the medium-term, a large number of saturated resin in the entrance section is not regenerated immediately, which cause excessive pollution.

After treatment stage,all resin runs desorption process although a large amount of resin at the bottom actually has adsorption capacity, which leads to waste. Because the discharge has been unable to meet requirements.

The multi-unit system is divide the large fixed bed into many separate units that are filled with resin. Thus, differentiation is available. As shown in Fig 3-2, while only a fraction of the upper layer of resin bed becomes saturated, immediately removed from the system and transferred to regeneration, and then it is recycled to new resin area of system in time. As long as the resin regeneration and recycle are coordinated, the whole system can run efficiently and continuously. Besides, the resin will be protected from excessive pollution result from soaking long time.

Fig 3-2  A schematic diagram of multi-unit ion exchange process.