Difference between internal and external treatment methods.

 Ans-:

Internal treatment (Corrective methods)-:

1) It is carried out in the boiler itself.

2) It is required in low-pressure boilers.

3) It is a corrective method.

4) It includes colloidal conditioning , carbonate conditioning, phosphate conditioning , calgon conditioning etc.

External treatment (Preventive methods)-:

1) It is carried out outside the boiler, before water enters the boiler.

2) It is required in high-pressure boilers.

3) It is a preventive method.

4) It includes zeolite process, lime-soda process and ion-exchange process.