Purpose of chemical cleaning :
The primary reasons for chemical cleaning of boilers/ heat exchangers are to prevent tube failures & improve unit availability. Tube failures in low pressure boilers/heat exchangers are normally the results of creep which occurs when internal deposits produce excessive metal temperature. A relatively smaller quantity of deposit creates difficulties in high pressure boilers. Caustic corrosion & hydrogen damage, which occur only in the presence of deposits, may cause tube failures at temperatures well below the creep limit. Deposits originating both from fabrication & during operation should be considered potential problems.