|
items |
unit |
request or conditions of usage |
allowable value |
|
turbidity |
NTU |
according to the requirements of production technology |
≤20 |
|
for plate heat exchanger, finned tube heat exchanger, spiral plate heat exchanger |
≤10 |
|
PH |
|
|
6.8-9.5 |
|
calcium hardness +
methyl orange
（in terms of CaCO3） |
mg/L |
stability index of calcium carbonate RSI≥3.3 |
≤1100 |
|
the temperature of side wall of heat transfer surface is over 70 °C70℃ |
calcium hardness is under |
|
Fe in total |
mg/L |
|
≤1.0 |
|
Cu2+ |
mg/L |
|
≤0.1 |
|
Cl- |
mg/L |
Carbon steel, stainless steel heat exchanger, tube pass |
≤1000 |
|
the temperature of side wall of stainless steel heat exchanger equipment and the side wall of heat transfer surface is under 70 °C
the temperature of cooling water is under 45℃ |
≤700 |
|
SO42-+Cl- |
mg/L |
|
≤2500 |
|
silicicacid
（in terms of SiO2） |
mg/L |
|
≤175 |
|
Mg2+×SiO2
（Mg2+ in terms of CaCO3） |
mg/L |
PH≤8.5 |
≤50000 |
|
free chlorine |
mg/L |
header outlet pipe of circulating water return |
0.2-1.0 |
|
NH3-N |
mg/L |
|
≤10 |
|
petroleum |
mg/L |
non-refinery |
≤5 |
|
refinery |
≤10 |
|
CODcr |
mg/L |
|
≤100 |
|
corrosion rate of carbon steel |
mm/a |
|
＜0.075 |
|
corrosion rate of copper |
mm/a |
|
＜0.005 |
|
corrosion rate of stainless steel |
mm/a |
|
＜0.005 |
