1、 First, investigate the core causes

The main reasons for the decrease in condensation efficiency are contamination of the heat exchange surface, abnormal refrigerant conditions, equipment structure/negative pressure problems, and pipeline gas blockage. They should be investigated and rectified in order of difficulty.

（1） Scaling, fouling, and attachment of impurities on the heat exchange surface (most common)

Phenomenon: The temperature difference of the condensate water decreases, the amount of condensate water is insufficient, and the output of distillate decreases.

rectification measures

Shutdown disassembly and cleaning: According to the scale quality selection plan, carbonate scale is cleaned with dilute acid circulation, biological sludge and oil stains are washed with alkaline cleaning agent+high-pressure water, and hard crystalline scale is cleaned with mechanical brushing.

Daily prevention: Install a filter at the inlet of the cooling water to intercept sediment and impurities; Add softening and scale inhibition devices to high hardness water sources, and regularly add scale inhibitors.

Develop maintenance cycle: regular working conditions require monthly inspections, shallow cleaning every quarter, and high impurity working conditions require monthly cleaning.

（2） The working condition of the cooling medium does not meet the standard

The temperature of the cooling water is too high

High temperature environment and poor heat dissipation of cooling towers are the main reasons.

Rectification: Clean up the cooling tower packing, spray pipes, and fan debris; Check the operation status of the fan and water pump to ensure full load operation; In summer, spray cooling and backup chiller units can be added to control the inlet water temperature within 25 ℃.

Insufficient cooling water flow

Pipeline blockage, aging of water pump, insufficient valve opening, and pipeline throttling can all lead to a decrease in flow rate.

Rectification: Fully open the pipeline valve and clear the blocked pipeline; Detect the head and flow rate of the water pump, and promptly repair or replace the aging pump body; Optimize pipeline layout to reduce resistance caused by bends and diameter changes.

（3） System gas blockage and accumulation of non condensable gases

The vacuum low-temperature evaporation system is prone to mixing air and non condensable gases, which adhere to the walls of the heat exchange tubes and form a gas film, greatly hindering heat exchange.

Phenomenon: Large fluctuations in vacuum degree, continuous deterioration of condensation effect, and significant decrease in equipment load.

rectification measures

Open the system exhaust valve for fixed-point exhaust, and discharge non condensable gases at regular intervals for each shift;

Thoroughly inspect the sealing points of the tank body, flanges, valves, instrument interfaces, pump body, etc., replace aging seals, repair leaks and prevent external air infiltration;

Optimize the pumping capacity of the vacuum pump, match the load of the condensing system, and timely extract non condensable components from the gas phase.

（4） Equipment structure and installation issues

Unreasonable arrangement of condenser tube bundles/plates, material deviation

Rectification: Check the water and steam distribution structure, adjust the guide plate and flow equalization device to ensure even contact between steam and cooling medium, and avoid local heat transfer blind spots.

Abnormal condensate level

Excessive liquid level flooding the heat exchange surface and low liquid level causing steam short circuit can both reduce efficiency.

Rectification: Calibrate the liquid level gauge, reset the normal operating liquid level range, adjust the discharge and reflux valves, and maintain stable liquid level.

2、 Optimization of operating process parameters

Match vacuum and steam loads

Adjust the vacuum degree of the system according to the evaporation rate to avoid steam generation far exceeding the condensation processing capacity, resulting in steam accumulation. Dynamically adjust the operating load during the concentration process to achieve a balance between steam production and condensation.

Optimize the temperature difference between cold and hot heat transfer

Reasonably increase the temperature difference between cold and hot media within the allowable range of equipment design; Short circulation of cooling water is strictly prohibited to ensure continuous supply of cold water and normal discharge of hot water.

Control feed and evaporation rate

Avoid overloading the equipment with feed and forcibly increasing production, and prevent the instantaneous steam volume from increasing beyond the condensation design capacity.

3、 Accessory upgrade and long-term optimization

Old condenser renovation

If the heat exchange plate/tube bundle is corroded, deformed, or the wall thickness is reduced, and cleaning alone cannot restore its performance, it is recommended to replace the heat exchange element; Corrosion resistant materials such as titanium and 316L are selected for corrosion conditions.

Add auxiliary condensing unit

When processing high concentration and high-capacity waste liquids, auxiliary condensers can be connected in parallel to share the load.

Install online monitoring instruments

Install temperature and pressure sensors at the inlet and outlet of the cooling water, as well as on the steam side, to monitor temperature and pressure differences in real time and provide early warning of data anomalies, achieving early detection and handling.

4、 Standardized operation and maintenance management (to prevent problems from recurring)

Establish a condensate system inspection table to record key data such as water temperature, water pressure, flow rate, vacuum degree, liquid level, etc. daily.

Distinguish water quality, develop cleaning and dosing plans, and create a ledger for retention.

Provide training for operators, standardize operations such as start stop, exhaust, and parameter adjustment, and prevent efficiency decline caused by improper human operation.