1、 Preparation before driving
1. Equipment inspection and debugging
Confirm that all equipment has completed maintenance and pipeline valves are in the closed state (such as vent valves and sampling valves).
Check if the circulating cooling water supply is sufficient, the water quality is free of impurities, the pressure is stable at 2-3.5kgf/cm ², and the temperature is ≤ 30 ℃.
Open the mechanical seal cooling water valves of all pumps to ensure normal flow of cooling water.
2. Raw material and steam preparation
The original liquid tank stores saline wastewater and adjusts the balance between feed rate and evaporation rate through the original liquid lifting pump.
Confirm that the boiler steam pressure meets the standard (such as 3.5kgf/cm ²), and test that the safety valve function is normal.
2、 System startup and operation
1. Start sequence
Start the vacuum pump → feed pump → each effect circulation pump (first effect → second effect → third effect) → discharge pump → steam main valve → condensate pump in sequence.
Steam is introduced in stages: the first steam enters the first effect heating chamber, and the second steam is sequentially transferred to the second and third effect heating chambers.
2. Forced loop control
Maintain the material flow rate at 1.5-5m/s through a forced circulation pump to prevent scaling and improve heat transfer efficiency.
The material circulates between the heating chamber and the evaporation chamber, spraying in a mist to increase the evaporation area.
3. Temperature and pressure regulation
First effect pressure>second effect>third effect, gradually reducing the boiling point (such as controlling the vacuum degree of the third effect to -0.08~-0.09MPa).
Real time monitoring of the liquid level in each evaporator chamber, adjusting the flow of condensate and secondary steam through valves.
3、 Salt and liquid discharge operations
1. Salt slurry treatment
Adopting the "conversion effect salt discharge" mode: the first effect salt slurry is discharged into the second effect circulation pipe, the second effect salt slurry is discharged into the third effect circulation pipe, and finally pumped by the salt slurry pump to the centrifugal separation of the salt settling device.
After the solid-liquid ratio of the salt slurry meets the standard, it will be transported outside and the centrifuged mother liquor will be returned to the evaporation system for further processing.
2. Discharge of condensate water
The first effect condensate water is directly recovered, the second effect condensate water enters the flash evaporation tank to generate secondary steam, and the third effect condensate water condenses with the final effect steam and is discharged outside the balance cylinder.
4、 Shutdown operation
1. Normal shutdown
Close the steam main valve → stop the feed pump → stop each circulating pump in sequence → close the discharge pump → stop the vacuum pump → delay the shutdown of the condensate pump.
Drain the residual materials in the evaporation chamber and open the drain valve to clean the pipeline.
2. Emergency response
In case of sudden malfunction, immediately close the steam valve, stop feeding, discharge the salt slurry, and start the tank washing system to flush the equipment.
5、 Maintenance and Precautions
1. Regular cleaning: remove scale from the heating tube and sediment from the crystallizer, and check the sealing performance of the pump unit.
2. Safety protection: Wear protective gear during operation to avoid contact with high-temperature components or corrosive media.