1. Material characteristics: the "inherent determinant" of efficiency

The inherent properties of the material are the foundation that affects evaporation efficiency. Firstly, it is the concentration and solid content: in wastewater with low concentration and low solid waste (such as lightly polluted cleaning wastewater), water molecules are prone to leave the system, resulting in a fast evaporation rate; whereas high-salt (salt content > 10%) and high-viscosity materials (such as chemical mother liquor) increase heat transfer resistance, slowing down evaporation and easily causing scaling on the tube wall. Secondly, the boiling point elevation characteristic: solutes (salts, organics) in the material will raise the boiling point above that of pure water, with a higher concentration resulting in a greater increase in boiling point. If it exceeds the low temperature range (≤60°C), additional vacuum enhancement or heating power is required, directly reducing energy efficiency. Furthermore, corrosivity and impurities are also crucial: wastewater containing strong acids and chloride ions (such as electroplating wastewater) can corrode heat transfer tubes, and suspended impurities (sediment, particles) if not pretreated, can adhere to form a fouling layer, reducing evaporation efficiency by 10%-20%.

II. Equipment design: "Hardware guarantee" for efficiency

The efficiency ceiling is determined by the structure of the equipment and the performance of its core components. Firstly, the heat transfer system: the larger the heat transfer area (such as multi-row tube design), and the higher the thermal conductivity of the material (such as 316L stainless steel vs plastic), the more thorough the heat exchange and the higher the evaporation rate; if there are dead zones or inadequate design for scaling risks on the heat transfer surface, it will directly drag down the efficiency. Secondly, the vacuum system: low-temperature evaporation relies on a vacuum environment to lower the boiling point. Insufficient vacuum (below -0.09 MPa) will lead to an increase in boiling point, slow pumping rate, or seal leakage, which will destroy the vacuum environment, causing fluctuations in evaporation efficiency or even downtime. Thirdly, the heating system: power needs to match the processing capacity. Insufficient power will result in slow evaporation, while excess power will lead to energy waste; energy-saving designs such as heat pump heating can recover secondary steam heat, improving efficiency by more than 30% compared to traditional electric heating.

III. Operating parameters: The "key to dynamic regulation" of efficiency

Rational regulation of parameters can maximize equipment efficiency. Temperature difference is crucial: if the temperature difference between the heating medium and the material is too small (less than 5°C), the heat transfer power is insufficient; if it is too large (greater than 30°C), it is prone to local overheating and scaling, which needs to be balanced according to the material characteristics (such as heat sensitivity). Material flow rate and distribution are also important: if the flow rate is too slow, it is prone to concentration and scaling, while if it is too fast, heat exchange is insufficient; if there is "flow deviation", it will waste heat transfer area and reduce overall efficiency. In addition, the concentration discharge cycle needs to adapt to changes in concentration: if high-concentration material is not discharged in time, it will lead to a continuous increase in concentration within the equipment, viscosity increases, and the evaporation rate significantly decreases.

IV. Maintenance operations: the "long-term stable foundation" of efficiency

Routine maintenance directly affects the rate of efficiency decay. Scale removal is a key focus: the thermal conductivity of the scale layer on the heat transfer surface is extremely low, and for every 1mm increase in thickness, efficiency decreases by 5%-15%. Regular acid cleaning or online cleaning is necessary to avoid excessive cleaning that could damage the equipment. The replacement of vulnerable parts cannot be ignored: leaks in vacuum seals, oil contamination of vacuum pumps, etc., can disrupt the vacuum environment, leading to a sudden drop in efficiency; mixer malfunctions can cause uneven mixing of materials, affecting heat transfer. At the same time, the effectiveness of pretreatment needs to be ensured: incomplete filtration and improper pH adjustment can allow impurities to enter the evaporator, block pipelines, or accelerate scaling, indirectly reducing treatment efficiency.

In summary, enhancing the efficiency of low-temperature evaporators requires full-chain optimization: adapting material pretreatment at the front end, designing equipment and adjusting parameters reasonably at the mid-end, and strengthening maintenance at the back end, in order to achieve efficient, stable, and low-energy consumption operation.