1. What core parameters should be paid attention to when selecting a forced circulation pump?

1. Determine the circulation flow rate based on evaporation volume

Evaporation volume is an important basic parameter for forced circulation pump selection.

It should be noted that:

Evaporation ≠ Circulation pump flow

Evaporation represents the amount of water or solvent evaporated by the system per unit time, while circulation pump flow represents the volume flow of materials circulating between the heater and evaporator.

Forced circulation systems usually require higher circulation rates:

Circulation flow = evaporation volume × circulation rate

For example:

The evaporation capacity of an evaporation system is:

• Evaporation volume: 5 t/h

• Cycle rate: 20 times

Theoretical circulation volume is approximately:

5 × 20 = 100 t/h

In actual engineering, it is also necessary to follow:

• Material concentration

• Solid content

• Crystallization tendency

• Heat exchanger structure

Correction.

For media that are prone to crystallization, such as high-concentration brine and chemical mother liquor, a higher circulation speed is usually required to reduce the risk of crystallization deposition.

2. Determine the pressure capacity of the forced circulation pump based on the system lift

2. The lift is mainly determined by the system resistance

The lift of the forced circulation pump is not the higher, the better, but needs to overcome the resistance of the entire circulation loop.

Mainly including:

Pipeline resistance

Including:

• Friction loss of inlet and outlet pipelines

• Local resistance of elbows and valves

• Pressure loss caused by changes in pipe diameter

Heat exchanger resistance

Heaters in evaporation systems usually have higher flow rate requirements, so heat exchange tube resistance may become the main source of pressure loss.

Evaporator structural resistance

Different types of evaporators:

• Forced circulation evaporator

• Multi-effect evaporator

• MVR evaporation system

There are differences in their circulation resistance.

Therefore:

Pump head = system static pressure difference + pipeline loss + equipment resistance + safety margin

Usually engineering design will increase the safety margin by 10% to 20%.

3. Typical applications of forced circulation pumps in projects

1. Chemical wastewater evaporation system

In high-salt wastewater treatment, forced circulation pumps require long-term transportation:

• High concentration brine

• Mother liquor

• Crystal slurry

Selection key points:

• Anti-corrosion materials

• Anti-crystallization design

• Stable and continuous operation

2. Evaporation system in the salt-making industry

The salt-making process requires a large amount of circulating brine.

The pump needs to meet:

• Large flow circulation

• Low energy consumption operation

• Long-term operation

3. MVR evaporation system

The MVR system has higher requirements for circulation stability.

The forced circulation pump needs to match:

• Evaporator heat exchange capacity

• Circulation rate

• System pressure conditions

Avoid the decrease in heat exchange efficiency due to insufficient flow.

IV. Frequently asked questions when purchasing forced circulation pumps

Q1: The evaporation capacity is 5 tons/hour, what flow rate is needed for the circulation pump?

Cannot be selected directly based on 5 tons/hour.

Needs to be calculated based on cycle magnification.

It is usually necessary to combine:

• Evaporator structure

• Material properties

• Heat exchange area

To determine the actual circulation flow rate.

Q2: Is the higher the lift of the forced circulation pump, the better?

No.

Excessive lift will cause:

• Increased motor power

• Increased energy consumption

• Abnormal system pressure

The correct way is to calculate based on the circulation pipeline resistance.

Q3: Why are pump models different for different projects with the same evaporation capacity?

Because the influencing factors are different:

• Different material concentrations

• Different temperatures

• Different corrosivity

• Different circulation rates

So the pump model cannot be matched only according to the evaporation capacity.

5. Suggestions for procurement and selection of forced circulation pumps

In order to ensure long-term stable operation of the equipment, buyers are recommended to provide the following information when providing technical parameters:

Process parameters

• Evaporation capacity (kg/h or t/h)

• Circulation method

• Evaporator type

Media parameters

• Medium name

• Concentration

• Density

• Viscosity

• Temperature

System parameters

• Required flow rate

• System head

• Pipe size

• Installation method

Professional pump manufacturers can perform hydraulic calculations based on these parameters to determine:

• Pump type

• Impeller design

• Motor power

• Material grade

• Sealing solution

6. Feiyue forced circulation pump solution

Feiyue Pump provides customized forced circulation pump solutions for chemical evaporation, salt production, wastewater treatment and concentration systems.

According to different working conditions, we can provide:

• Large flow low-lift circulation pump

• High-temperature corrosion-resistant circulation pump

• Special circulation pump for chemical media

• MVR evaporation system circulation pump

By combining evaporation volume, circulation rate, lift and medium characteristics for selection, we help customers reduce operating energy consumption and improve evaporation system stability.

If you are designing a new evaporation project, available:

• Evaporation

• Medium parameters

• Temperature

• Flow requirements

• Height requirements

The Feiyue Engineering team can provide matching forced circulation pump solutions based on actual working conditions.