Soot and Scale Control

Control of soot and scale build-up is a critical factor in  maintaining  fuel  economy  in  any  type  of  steam producing  equipment.  They  act  as  insulation  and inhibit heat transfer so that more fuel is required to generate  the  same  level  output.

In  fact,  one-eighth of  an  inch  of  soot  build-up  provides  approximately the same amount of insulation as five-eighths of an inch of asbestos.
It  is  easy  to  see  how  this  accumulation  of  fire  side soot and  water side scale  translates into  increased fuel consumption and operating costs.


All  oil  fires  create  some  soot.  As  soot accumulates  in  fire-tube  boilers  and  steam generators, its presence is detected by increases in  stack temperature. The Clayton Steam Generator is equipped with a standard built-in steam soot blower that is designed to be used in the course of normal operation.  Soot  blowing  on  a  daily  basis  is encouraged  to  ensure  continuing  high  level performance. Fire-tube boilers on the other hand do not offer steam soot blowing as standard equipment.

Typically, fire-tube boilers require extensive cleaning with  rods  and  brushes  -  an  expensive  and  time-consuming  process,  requiring  boiler  shut-down.  In contrast,  the  Clayton  Steam  Generator  design allows soot removal during operation or by flushing the unit out with water without major shut-down. For this reason, soot removal is done much more easily on  the  Clayton  unit,  helping  to  maintain  peak efficiency.


All  steam  generating  equipment  must  be monitored for scale accumulation. Although it can be prevented  through  water  treatment  and maintenance,  it  is  an  advantage  to  be  able  to monitor  for  scale  build-up  and  to  remove  it  easily when it does occur.

Because of Clayton’s unique monotube coil design, scale  is  positively  detected  during  operation  by simply  observing  feedwater  pressure.  Increased pressure  means  scale  is  forming.  This  is  not  the case  with  a  multipass  fire-tube  boiler  which  must rely  on  stack  temperature  increases  or  shut-down and physical inspection to detect scale build-up.

If  scale  does  accumulate  in  a  Clayton  Steam Generator,  the  forced  flow  design  allows  for  a reverse flow “blowdown” to remove sludge and soft scale.  In  more  severe  cases  hard  scale  may  be removed by acid washing using the steam generator pump for circulating the acid. Scale removal in a fire-tube  boiler  is  much  more  tedius  and  time consuming.  Mechanical  access  to  all  areas  is impossible  and  washing  is  difficult  and  uncertain. Clayton’s  monotube  design  ensures  that  every square foot of surface is washed.

ln  summary,  all  types  of  steam  generating equipment are subject to impaired efficiency due to the accumulation of soot and scale. Clayton’s steam generator  design  incorporates  several  features  that make  monitoring  and  removal  of  soot  and  scale faster  and  easier  to  accomplish.  Clayton  Steam Generators  are  designed  to  stay  in  peak  operating condition  throughout  the  most  demanding  work schedules.  In  contrast,  fire-tube  boilers  have  many disadvantages  when  it  comes  to  monitoring  and removing soot and scale, making it more difficult and expensive to keep them running efficiently.

1/16” of scale requires 15% more fuel
1/8”  of scale requires  20% more fuel
1/4”  of scale requires  39% more fuel
3/8”  of scale requires  55% more fuel
1/32”  of soot requires  12% more fuel
1/16”  of soot requires  29% more fuel