For a new evaporator, why is there always a desire to max out its production capacity as soon as it is put into operation?

Many enterprises encounter such a "pleasant surprise" when they have just put a new evaporator into operation: an evaporator designed for 500 tons can reach 600 tons or even 650 tons right after startup. Additionally, the new equipment is clean and free of scaling, its heat transfer efficiency is at its maximum, and there is an extra 10% surplus in heat transfer area—all of which makes enterprises feel that "producing more is definitely the right move."

Especially for long-established enterprises that have switched to 7-effect evaporators — compared with their previous 5-effect and 6-effect ones, the new equipment features a lower steam-water ratio and lower energy consumption, making enterprises even more eager to let it "handle more workload": they operate the 7-effect evaporator at full load or even overload, shift the production capacity from the 5-effect and 6-effect evaporators to it, and aim to further reduce costs. However, this hasty capacity-increasing operation method actually hides many hidden risks!

Many people have not noticed the two major risks of blind overproduction.

A new evaporator may seem durable, but operating beyond its rated capacity will directly hit the weak points in its design.

Overcapacity equals a tendency to experience alkali carry-over, compromising production stability.

The separation chamber of an evaporator is designed based on its rated capacity — for example, for a 500-ton evaporator, the size of the separation chamber and its empty tower gas velocity are both precisely matched to this capacity. Once the production capacity exceeds 600 tons, the empty tower gas velocity will far surpass the designed value, leading to severe entrainment of solution droplets — what we commonly refer to as "alkali carry-over". This not only causes material loss but also may contaminate subsequent processes, which in turn disrupts the production rhythm.

Suddenly increasing steam pressure = scaling acceleration and equipment lifespan "shortening".

To pursue higher production capacity, many enterprises will directly increase the steam pressure, significantly widen the temperature difference of the 1st effect, and cause the material temperature of the 1st effect to rise sharply. However, doing so will lead to rapid scaling in the 1st effect and 2nd effect.

Originally, the solutions of new enterprises are clean and have a simple composition, so their new evaporators can be cleaned once every six months.

For long-established enterprises, when using old evaporators, their scaling cycle is only 2 months.

However, once operated under over-temperature and over-pressure conditions, a new evaporator may become fully scaled in just 2 months, and the frequency of acid cleaning doubles!

Frequent acid cleaning not only increases costs but also corrodes the equipment, which directly shortens the service life of the evaporator—making the gains not justify the losses.

Correct commissioning of a new evaporator: Stability is more important than speed.

In fact, the core advantage of a new evaporator lies in "long-term stable operation" rather than "short-term rush for production capacity". The correct operation method is very simple: operate it according to its rated water evaporation capacity — for example, if it is designed for 500 tons, run it at 500 tons, and don’t be greedy for more.

Doing so offers 3 key benefits:

? Better steam-water ratio: Under rated load, the utilization efficiency of secondary steam is at its highest, and energy consumption will not rise conversely due to overproduction.

? Longer equipment service life: Avoiding accelerated scaling, reducing the frequency of acid cleaning, and enabling the equipment to maintain good condition for a long time.

? Purer condensed water: Without excessive entrainment of droplets, the purity of the secondary condensed water is higher, which can reduce the cost of subsequent treatment.

Conclusion

A new evaporator is like a "new car" — don’t rush to "step on the gas hard" when you first start using it. Operating it steadily according to its rated capacity not only allows it to give full play to its energy-saving advantages but also prolongs its service life. After all, for production, "long-term stability" is more important than "temporary high production".