One question per week; answers win prizes. Question 4 from Chlor-alkali Chemistry (Basic Chemical Engineering Knowledge)
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This post was last edited by sunjl1981 on 2013-1-6 at 23:50. Let’s discuss what everyone knows regarding the design parameters and control criteria for saline water filters (including what type of membrane is used). Let’s learn together; those who provide detailed and comprehensive responses will receive double points. As usual, those who post in violation of the rules, copy content, or post irrelevant messages will have their points deducted doubly -
This post was last edited by T^P on 2010-7-4 at 19:35. Process control parameters for the single-saltwater process: Brine: NaCl > 290 g/l; At the outlet of the pressure pump: NaOH: 0.1–0.3 g/l; In the feed tank: Na2CO3: 0.3–0.6 g/l. Concentrations in the acid cleaning solution: 15%; Ferric chloride concentration: 1%; Sodium sulfite concentration: 5%; Sodium carbonate concentration: 20%. At the outlet of the membrane: SS < 1 mg/l. In the concentrated brine tank: SO42- < 5 g/l; Total amines < 4 mg/l; Inorganic ammonium < 1 mg/l. In the concentrated brine tank: Fe2+ + Fe3+ ≤ 1.0 mg/l; Ca2+ + Mg2+ ≤ 1.0 mg/l. Free chlorine level: 0; pH: 9–10. Steam pressure: 0.35 Mpa; Pressure of water used in production: 0.4 Mpa; Pressure of water used in circulation: 0.4 Mpa; Pressure of process air: 0.5 Mpa; Pressure of instrument air: > 0.5 Mpa. Temperature of E101: 55±5°C. Liquid level in the pressure-dissolved air tank: at the middle of the intermediate sight glass. For nitrogen removal using membranes: NaCl ≤ 220 g/L; NaClO3 ≤ 7 g/L; SO42-: 6.6–8 g/L; Free chlorine: not detected; pH: 7.5–8.5; Temperature: 55–60°C; SS < 1 ppm. In the saltwater receiving tank, NaCl concentration is ≤195 g/L; at the outlet of the first-stage pump, NaCl concentration is ≤290 g/L. In the water distribution tank, SO42- concentration is <5 g/L
Process control parameters for the single-saltwater process: NaCl > 290 g/l; NaOH: 0.1–0.3 g/l; Na2CO3: 0.3–0.6 g/l; SS < 1 mg/l; SO42- < 8 g/l; total amines < 4 mg/l; inorganic ammonium < 1 mg/l
Reply to 3# wu*an3522: The saltwater concentration of you guys is way too low. Are you using Asahi Kasei’s electrolyzers? If so, when concentrated saltwater is mixed with dilute saltwater in a 7:1 ratio and fed into the electrolyzer, isn’t the concentration still too low?
This post was last edited by wz16 on 2010-7-13 at 21:20. Acceptable parameters for saline water:
Parameter | Value
NaCl concentration | 305±5 g/l
pH value | 9–11
Ca2++Mg2+ | ≤10 mg/l
S.S. | ≤1 mg/l
Fe3++Fe2+ | ≤0.1 mg/l
Si2+ | ≤2.3 mg/l
I- | ≤0.2 mg/l
ClO3- | ≤7 g/l
SO42- | ≤5 g/l
Ni2+ | ≤0.05 mg/l
Free chlorine | 0
Sr2+ | ≤2.5 mg/l
Al3+ | ≤0.1 mg/l
Ba2+ | ≤0.1 mg/l
Mn | ≤0.085 ppm
Equipment parameters:
Membrane filter – Filter area: 100.0㎡; Filter pressure: <0.15 MPa; Operating temperature: <60°C. The required compressed air pressure is 0.5 MPa–0.6 MPa
Parameter | Value
NaCl concentration | 305±5 g/l
pH value | 9–11
Ca2++Mg2+ | ≤10 mg/l
S.S. | ≤1 mg/l
Fe3++Fe2+ | ≤0.1 mg/l
Si2+ | ≤2.3 mg/l
I- | ≤0.2 mg/l
ClO3- | ≤7 g/l
SO42- | ≤5 g/l
Ni2+ | ≤0.05 mg/l
Free chlorine | 0
Sr2+ | ≤2.5 mg/l
Al3+ | ≤0.1 mg/l
Ba2+ | ≤0.1 mg/l
Mn | ≤0.085 ppm
Equipment parameters:
Membrane filter – Filter area: 100.0㎡; Filter pressure: <0.15 MPa; Operating temperature: <60°C. The required compressed air pressure is 0.5 MPa–0.6 MPa