Phosphate dosing device

Phosphate dosing deviceProcess Principle
The hardness of calcium and magnesium in boiler feedwater can undergo chemical reactions or concentrate and crystallize at high temperatures, forming insoluble scale that firmly adheres to the heating surface of the boiler. This scale is a poor conductor of heat and can hinder heat conduction. In severe cases, it may lead to boiler tube bursting accidents. In addition, it can also induce and exacerbate chemical corrosion of metals under the scale, which is quite harmful.
Although the boiler condensate and feedwater have undergone strict softening and desalination treatment, there is still a small amount of calcium and magnesium hardness entering the boiler water. If this hardness is not treated, scaling will also pose a threat to the safe operation of the boiler. Currently, adding phosphate to the boiler water is the most suitable treatment method. The reaction is as follows:
10Ca2++6PO43-+2OH Ca 10 (OH) 2 (PO4) 6 (basic calcium phosphate)
Alkaline calcium phosphate is a soft water residue that is easily discharged with boiler discharge and will not adhere to the boiler to form scale.

Phosphate dosing deviceProcess Overview
The dosing device mainly includes four parts: the drug solution preparation system, the metering and dosing system, the safety system, and the control system.
Solid phosphate is added to the dissolution tank, and then mixed with desalinated water or condensed water in proportion to dissolve. It is then added to the boiler steam drum through a metering system. The dosing control can be done manually or automatically based on the control signal output by the upper system.
Scope of application: Boiler water treatment for high-pressure and higher parameter steam drum boilers.

1、 Function of dosing device

The dosing device is used for automatic adjustment of the pH value of boiler feedwater, keeping the pH value of boiler feedwater at a certain level

Operate within the normal range to prevent acid-base corrosion of boilers and other thermal equipment caused by pH imbalance in the feedwater, ensuring that the thermal system operates in a normal state and saving 30-50% energy. The use of ammonia can save 20-30%. Extend the service life of thermal equipment and ensure its stable and safe operation.

2、 Working principle and characteristics of dosing device

The device consists of a control system and a dosing system. The control system consists of an industrial acidity meter, a regulator, a frequency converter, and a control circuit. The dosing system consists of a dosing pump and a dosing box.

The sample water is cooled by a cooler to a temperature between 20-35 ℃. The pH value of the tested sample water is detected by an acidity meter, which displays it in digital form and converts it into a standard signal of 4-20mA for output to the MPS programmable controller. The MPS programmable controller compares the input signal with the given value, performs logical operations according to a certain algorithm based on the comparison result, and outputs the corresponding 4-20mA current to control the frequency converter to change the speed of the dosing pump motor. The change in the speed of the dosing pump motor meets the requirements for controlling the dosing pump volume, so that the parameters of the controlled object run in the * state. The system is equipped with a protection function: when the liquid level in the medicine tank is low, a low level contact signal is sent to the MPS, and the MPS will not start the dosing pump. When the pressure in the dosing pipeline is high, a high pressure signal contact is sent to MPS, and MPS will not start the dosing pump. (These two contact signals are provided by the user, or these two sets of instruments can be ordered when placing an order)

3、 Characteristics of dosing device

1. The pH meter of the dosing device is an intelligent instrument with a microcontroller, and the electrode is an integrated electrode, which accurately reflects acidity.

2. The dosing device controller is a MPS programmable controller with flexible and stable characteristics.

3. Users of the dosing device can choose whether to use a frequency converter based on the type of dosing pump they are using.

4. The control method of the dosing device is fuzzy control, which can eliminate the phenomenon of large amplitude oscillation

4、 Ordering Notice

1. The pressure of the controlled medium is used to select the model and motor power of the metering pump.

2. The order for the dosing device specifies whether it is a set of control system or two sets. Do you need a spare pump.

3. The control cabinet of the dosing device must indicate whether the dosing pump is an electromagnetic pump. Is there a matching medicine box and automatic control device.

4. Use a motor to power the dosing pump, indicate whether the motor is a single-phase or three-phase motor, and also indicate the power of the motor.