Factors related to heat transfer performance

Heat transfer is the core process of evaporation, and the heat transfer efficiency directly determines the processing efficiency. The main influencing factors are:

Heat exchange area and material: The larger the heat exchange area, the more heat is transferred per unit time; The higher the thermal conductivity of the material (such as titanium alloy>stainless steel>carbon steel), the stronger the heat transfer efficiency. If the heat exchange tube is scaled, blocked, or corroded, it will significantly reduce the effective heat transfer area and thermal conductivity efficiency.

Temperature difference of heat exchange medium: The temperature difference between the heating medium and the wastewater is the driving force for heat transfer, and a small temperature difference can lead to a decrease in heat transfer rate; However, excessive temperature difference can easily lead to local overheating and accelerated scaling, which can have the opposite effect.

Medium flow rate: If the medium flow rate in the shell or tube side is too low, it will form a boundary layer thermal resistance, hindering heat transfer; If the flow rate is too high, it will increase system resistance and energy consumption, and it needs to be controlled within the optimal flow rate range designed by the equipment.

Factors related to operating conditions

The rationality of operating parameters determines whether the evaporator is in efficient operation, and the main influencing factors are:

Vacuum degree and temperature: The higher the vacuum degree, the lower the boiling point of wastewater and the easier it is to evaporate; However, excessive vacuum will increase the load on the vacuum pump and may cause secondary steam to carry wastewater, affecting evaporation efficiency. It is necessary to match the characteristics of wastewater and set the optimal vacuum degree and heating temperature.

Feed load and stability: Overloading can lead to insufficient residence time of wastewater in the evaporator, resulting in incomplete evaporation; Excessive fluctuations in feed volume can disrupt the balance of operating conditions, and frequent start stop or parameter adjustment can significantly reduce processing efficiency.

System pressure stability: Poor sealing of the vacuum system, vacuum pump failure, etc. can cause fluctuations in vacuum degree, changes in the boiling point of wastewater, disorder of heat transfer process, and decreased treatment efficiency.

Factors related to material characteristics

The properties of the wastewater to be treated directly affect the difficulty of evaporation, and the main influencing factors are:

Wastewater concentration and viscosity: The higher the wastewater concentration and viscosity, the poorer the fluidity, the greater the heat transfer resistance, and the easier it is to form a scale layer on the heat exchange surface; If the concentration exceeds the rated processing range of the equipment, there will be an "evaporation limit" and the efficiency will sharply decrease.

Impurities and components: Suspended solids, colloids, calcium and magnesium ions in wastewater are prone to deposit on the surface of heat exchange tubes, forming scales and reducing heat transfer efficiency; High boiling point organic compounds increase the heat required for evaporation and prolong the processing time.

PH value: If the pH value of the wastewater is too high or too low, it may corrode the heat exchange pipes, or cause the crystallization and precipitation of salt substances, blocking the pipelines and heat exchange surfaces.

Factors related to equipment status

The maintenance and configuration of equipment directly affect operational efficiency, with the main influencing factors being:

Equipment maintenance situation: Failure to clean the scale on the heat exchange surface in a timely manner, damage to the insulation layer leading to heat loss, aging of seals leading to vacuum leakage, etc., can all cause a decrease in efficiency.

Auxiliary equipment performance: The performance of auxiliary equipment such as circulation pumps, vacuum pumps, and condensation systems can affect material circulation speed, vacuum stability, and secondary steam condensation efficiency, thereby affecting overall processing efficiency.

Equipment configuration level: Compared with evaporators equipped with MVR heat pumps and waste heat recovery devices, traditional evaporators have lower heat utilization rates and a processing efficiency gap of up to 30% -50%.