Yin type resin ion exchanger

1、 Equipment Introduction

Ion exchange is a commonly used method in water treatment technology. It is a water treatment equipment that uses the selectivity and equilibrium reaction principle of cation anion exchange resin to remove electrolyte ions from water. It is widely used in water treatment, especially in the production of high-purity water.

Ion exchange is carried out through ion exchange resin in electrolyte solution, which can remove various anions and cations in water. It is an irreplaceable means in the current process of preparing high-purity water.

Ion exchangers are divided into cation exchangers, anion exchangers, etc.

When the raw water passes through the ion exchange column, the cations and anions (HCO - ions) in the water exchange with the H+ions of the cation resin and the OH - ions of the anion resin in the exchange column, thereby achieving the purpose of desalination. The different combinations of yang and yin mixed columns can achieve higher water quality requirements.

2、 Working principle

After cation exchange, acidic water enters the anion exchanger containing OH type anion exchange resin, and the following reaction occurs:

H2SO4+2ROH- → R2SO4+2H2O

H2CO3+2ROH- → R2CO3+2H2O

HCI+ROH-→RCI+H2O

H2SiO3+ROH- → RHSiO3+H2O

From this, it can be seen that after cation anion exchange treatment, various ions in the water are almost removed, and generally more than 99% of the salt content in the water can be removed.

3、 Structure Overview

(1) Water inlet device

A water inlet device is installed on the upper part of the exchanger to evenly distribute water energy.

(2) Middle row device

The middle discharge device is set at the interface between the cation (anion) resin and the pressure layer, used to discharge acid (alkali) waste liquid and small backwash water during regeneration. The type is DN500-600, and the middle discharge is a double main pipe type. The DN800-DN3200 type is a branch main pipe type, with small holes on the pipe. The pipe is covered with plastic window gauze and a layer of 60 mesh nylon mesh. All materials are 1Cr18Ni9Ti.

(3) Drainage system

Equipment with a diameter of DN1200 and below adopts a porous plate with a treasure tower ABS type water filter cap. Equipment with a diameter of DN1500 and above has two forms of porous plate with a filter cap and a sand cushion layer. The porous plate varies according to the equipment specifications. The DN500 to DN600 types are made of rigid polyvinyl chloride, and the DN800 to DN3200 types are lined with steel adhesive. In addition, one sight glass is installed at the outlet of the drain cap at the bottom of the exchanger, at the resin surface, and at the height of the large backwash expansion to observe the working conditions inside the body. A resin input port is provided at the upper part of the cylinder, and a resin discharge port is provided near the porous plate at the lower part of the cylinder. Both the input and discharge of resin can be achieved through hydraulic transportation.

4、 Usage method

(1) Resin treatment

Before installing the resin into the exchanger, it should be screened first, then soaked in 8-10% NaCl solution for 20 hours, drained of salt water, and rinsed with water until the effluent no longer turns yellow. Alternatively, soak in a 5% HCl solution for 2-4 hours, drain the acid, and rinse the resin with water until the drainage is close to neutral. Load the resin into the equipment to the specified height, and perform a backwash after the resin is installed.

(2) Run

A certain height of water cushion layer must be maintained inside the equipment to prevent water from directly impacting the pressure layer on the resin layer. Before putting into operation, a positive wash must be carried out. The inlet valve (D1) and exhaust valve should be opened. When the water is full, the exhaust valve should be closed and the positive wash drainage valve (D5) should be opened until the water quality is qualified before starting operation. That is, the positive wash drainage valve (D5) should be closed and the outlet valve (D2) should be opened.

(3) Regeneration

When the effluent quality exceeds the standard or a certain volume of desalinated water is generated, the ion exchanger needs to be regenerated. The regeneration steps are as follows:

(a) Small backwash: Before regeneration, a small backwash should be carried out on the pressure layer above the middle drain pipe to wash away the dirt accumulated on the pressure layer and the middle drain device during operation. That is, the small backwash inlet valve (D7) and backwash drain valve (D4) should be opened, and the backwash flow rate is generally 5-10 meters/hour for about 15 minutes. After the small backwash is completed, close the small backwash inlet valve (D7) and backwash drain valve (D4).

(b) Entering the regeneration liquid: Open the regeneration liquid valve (D6) and the intermediate discharge valve (D8), the regeneration liquid enters from the lower part, and the waste liquid is discharged from the intermediate discharge port. To ensure the regeneration effect, a certain concentration and flow rate of the regeneration solution should be controlled.

(c) Small positive washing: During the process of entering the regeneration solution, some waste acid (alkali) infiltrates into the pressure layer. In order to save water consumption and shorten the positive washing time, this part of the waste liquid is washed away by the small positive washing method before the positive washing. When washing, open the inlet valve (D1) and then open the middle drain valve (D8). The water is discharged from the middle drain and the flow rate is controlled at 10-15 meters/hour for about 5-10 minutes.

(4) Washing in progress

After the small positive washing is completed, close the middle drain valve (D8) and open the positive washing drain valve (D5) for positive washing. The flow rate should be the same as the operating flow rate. When the effluent quality meets the requirements, close the drain valve (D5) and open the effluent valve (D2) to put it into operation.

(5) The Great Purge

Due to the compaction and contamination of the exchange agent, which can affect normal operation, a major backwash must be carried out after several cycles of operation. The interval between major backwashs can be determined based on the inlet turbidity, outlet quality, operating pressure difference, and exchange capacity of the factory. Generally, it is carried out once every 10-20 cycles. After the major backwash, the exchange agent layer is disrupted. In order to restore normal exchange capacity, the regeneration agent should be increased by 0.5-1.0 times during the regeneration after the major backwash. When conducting a large-scale backwash, open the inlet valve (D3) of the large-scale backwash, and the valve should be gradually increased from small to large. (D4) Perform backwashing. The backwash time is about 10-15 minutes.

Five Equipment specifications

(1) Design pressure: 0.59MPa Test pressure: 0.88MPa

(2) Operating flow rate: Fixed bed: 15-25m/h Floating bed: 40-50m/h Mixed bed: 40-120m/h

(3) Working temperature: 5-50 ℃

(4) Water quality: Softened water equipment: Hardness ≤ 0.03ml/L Grade 1 pure water equipment: Conductivity<10-3s/m

(5) Inlet turbidity: ≤ 5mg/L