water  treatment  chemist  should  be  consulted  and his or her recommendations for the chemical treat- ment  of  boiler  water  should  be  followed.  The degree of success of any water treatment program depends  upon  how  well  the  recommendations  for treatment  are  monitored.  When  the  services  of  a qualified water treatment chemist are obtained, his or   her   recommendations   should   include   the following: l l l l The treatment formula The treatment ingredients Instructions to the boiler operator in the use of the treatment Periodic visits to the plant to check on the results of the treatment plan When  the  operator  follows  instructions  and uses  the  proper  blowdown  procedure,  scale  and sludge  in  the  boiler  are  reduced  to  a  minimum. Blowdown  limits  the  amount  of  dissolved  and suspended solids in the boiler water. Consulting  a  chemist  is  an  ideal  situation. Seabees   seldom   operate   under   ideal   situations, particularly   during   contingency   operations.   How do you determine the initial chemical treatment for a   boiler,   and   then,   how   do   you   establish   an effective   treatment   program?   Some   general guidelines  follow. The  first  determination  you  have  to  make  is the steaming rate of the boiler, expressed in pounds per hour. This is a fairly simple computation. You first  determine  the  boiler  horsepower  (bhp);  then multiply  the  result  by  4.5  pounds.  For  example,  if you  have  a  100  horsepower  boiler  operating  at one-half fire, your steaming rate is 1,725 pounds of steam per hour. 1  BHP  =  34.5  lb  steam/hour 100 x 34.5 = 3,450 steam/hour at high fire 3,450 ÷ 1/2 =1 .725 lb steam/hour at one-half fire To determine the initial chemical dosage, you must  know  the  hardness  of  the  raw  water.  A chemist can tell you this; however, in the field you must determine it by experimentation. The harder 12-37 the   water,   the   more   phosphates   you   must   add during   treatment   to   obtain   correct   phosphate residuals.  The  example  that  follows  assumes  zero hardness of the raw water and uses a 1,725-pound steaming  rate.  1.  Mix  the  following  chemicals  in 28  gallons  of  water: a.  1  1/4  pounds  of  sodium  sulfate b.  1/2  pound  of  trisodium  phosphate c.  1/2  pound  of  caustic  soda 2.  Adjust  the  chemical  feed  rate  to  3  gallons per   hour   (allows   for   8-   to   10-hours   of steaming). The chemical dosage varies with the steaming rate   of   the   boiler.   To   establish   your   water treatment  program,  use  the  following  steps  every hour  of  operation  for  the  duration  of  your  initial chemical  batch. 1.  Determine  the  hourly  steaming  rate 2.  Test  for  phosphate  residual  (30-60  ppm) 3.  Test  for  sulfite  residual  (25-50  ppm) 4.  Test  for  pH  (9.5  to  11.5) 5.  Test  for  TDS  (3,000  to  4,000  ppm) You  should  make  a  log  entry  of  these  test  results every  hour.  This  establishes  a  history  of  the  test results.  At  the  completion  of  the  initial  chemical dosage,  you  can  either  add  or  subtract  chemicals, based on your log. It may take several batches fed over  an  8  to  10  hour  period  to  get  a  consistent chemical  requirement  for  boiler  water  treatment. Once  the  boiler  has  stabilized  and  treatment  test results remain reasonably balanced, testing may be required only every 4 hours. At  this  time  you  can  chart  your  chemical requirements, based on load demand of the boiler. B y    e s t a b l i s h i n g    t h i s    h i s t o r y    t h r o u gh experimentation,  your  operators  are  able  to  treat the boiler water with fairly accurate results. At this time note that boiler blowdown has a big effect on your   treatment   program.   Proper   blowdown practices  cannot  be  overemphasized.  Too  little blowdown  causes  TDS  readings  to  be  high;  too much  blowdown  causes  a  high  demand  for chemicals  and  results  in  lost  efficiency  of  the boiler. MAINTENANCE The  subject  of  boiler  maintenance  covers  a wide  range  of  topics.