Sulfuric acid index
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What are the technical specifications for sulfuric acid as a product? How is the control of key indicators achieved?
They’re all available in the sulfuric acid section; take a closer look – you’ll gain something from it.
You can check the standards; the Ministry of Chemicals has them
**Process Control Parameters for Various Positions in the Company’s Sulfuric Acid Production Plant
I. Process parameters for the sulfur melting unit:
1. Vapor pressure of melted sulfur: 0.5 Mpa–0.6 Mpa
2. Insulation vapor pressure: 0.35 Mpa–0.45 Mpa
3. Temperature of liquid sulfur: 135°C–145°C
4. Operating pressure of the filter: <0.75 Mpa; pressure difference: <0.3 Mpa
5. Sulfur content in liquid sulfur: ≤20 ppm
6. Ash content in liquid sulfur: ≤30 ppm
7. Liquid sulfur level in each tank: 60–80%
8. Analysis items:
- No. 1: Sulfur content in liquid sulfur; sampling point: intermediate tank; frequency: once per day
- No. 2: Ash content in liquid sulfur; sampling point: intermediate tank; frequency: once per day
- No. 3: pH of condensate water; sampling point: condensate tank; frequency: once per day
II. Process parameters for the sulfur burning and conversion unit:
| No. | Parameter name | Unit | Control range |
|-----|----------------|------|---------------|
| 1 | Temperature of liquid sulfur | °C | 135–145°C |
| 2 | Insulation vapor pressure of the liquid sulfur tank | MPa | 0.3–0.4 |
| 3 | Temperature at the middle part of the sulfur burning furnace | °C | 1000–1050°C |
| 4 | Temperature at the outlet of the sulfur burning furnace | °C | ≤1025°C |
| 5 | SO2 concentration at the outlet of the sulfur burning furnace | % | 9–10.5% |
| 6 | Moisture content in dry air | g/Nm3 | <0.1 |
| 7 | Temperature of the flue gas at the boiler inlet | °C | ≤1025°C |
| 8 | Pressure in the boiler drum | Mpa | 3.40–3.82 |
| 9 | Temperature of the flue gas at the inlet of Air Exchanger No. 2 | °C | 560–580°C |
| 10 | SO2 concentration at the inlet of Stage 1 | % | 9–10.5% |
| 11 | Temperature of the gas entering the catalyst in Stage 1 | °C | 415–420°C |
| 12 | Temperature of the gas exiting the catalyst in Stage 1 | °C | 595–620°C |
| 13 | Temperature of the gas entering the catalyst in Stage 2 | °C | 440–445°C |
| 14 | Temperature of the gas exiting the catalyst in Stage 2 | °C | 505–525°C |
| 15 | Temperature of the gas entering the catalyst in Stage 3 | °C | 440–445°C |
| 16 | Temperature of the gas exiting the catalyst in Stage 3 | °C | 465–485°C |
| 17 | Temperature of the gas entering the catalyst in Stage 4 | °C | 415–420°C |
| 18 | Temperature of the gas exiting the catalyst in Stage 4 | °C | 440–460°C |
8. Analysis items:
- No. 1: Moisture content in the air entering the furnace; sampling point: air inlet of sulfur burning furnace; frequency: once per day
- No. 2: SO2 concentration at the inlet of Stage 1; sampling point: inlet of Stage 1; frequency: once per shift
- No. 3: SO2 concentration at the exit of Stage 3; sampling point: exit of Stage 3; frequency: once per shift
- No. 4: First-stage conversion rate
- No. 5: SO2 concentration at the exit of Stage 4; sampling point: exit of Stage 4; frequency: once per shift; Second-stage conversion rate
III. Process parameters for the dry absorption unit:
| Parameter | Specified range |
|-----------|-----------------|
| Moisture content in the gas exiting the drying tower | <0.1 g/Nm3 |
| Temperature of the gas entering the absorption tower | 170–180°C |
| Acid mist in the gas exiting the drying tower | <0.03 g/Nm3 |
| Acidity of the acid in the drying tower | 98–98.5% |
| Acidity of the acid in the absorption tower | 98–98.5% |
| Absorption efficiency | >99.95% |
| Temperature of the acid in the drying tower | <65°C |
| Liquid level in the circulation tank | 60–70% |
| Temperature of the acid in the absorption tower | 70–80°C |
| Concentration of the final sulfuric acid product | >98% |
IV. Process parameters for the circulating water system:
1. Temperature of water entering the tower: 38–40°C
2. Temperature of water exiting the tower: 28–30°C
3. Volume of cooling water used: 1500–3000 m3/h
4. pH value of circulating water: ≥7.5
5. Suspended solids in circulating water: ≤50 mg/L
6. Temperature of pump bearings: ≤75°C V.1. Anodic protection control parameters (see Table 1) Table 1: Parameters Dry acid Absorbed acid Remarks Acid concentration (%): 93±0.5% 98±1% Outlet water temperature (°C)
I. Process parameters for the sulfur melting unit:
1. Vapor pressure of melted sulfur: 0.5 Mpa–0.6 Mpa
2. Insulation vapor pressure: 0.35 Mpa–0.45 Mpa
3. Temperature of liquid sulfur: 135°C–145°C
4. Operating pressure of the filter: <0.75 Mpa; pressure difference: <0.3 Mpa
5. Sulfur content in liquid sulfur: ≤20 ppm
6. Ash content in liquid sulfur: ≤30 ppm
7. Liquid sulfur level in each tank: 60–80%
8. Analysis items:
- No. 1: Sulfur content in liquid sulfur; sampling point: intermediate tank; frequency: once per day
- No. 2: Ash content in liquid sulfur; sampling point: intermediate tank; frequency: once per day
- No. 3: pH of condensate water; sampling point: condensate tank; frequency: once per day
II. Process parameters for the sulfur burning and conversion unit:
| No. | Parameter name | Unit | Control range |
|-----|----------------|------|---------------|
| 1 | Temperature of liquid sulfur | °C | 135–145°C |
| 2 | Insulation vapor pressure of the liquid sulfur tank | MPa | 0.3–0.4 |
| 3 | Temperature at the middle part of the sulfur burning furnace | °C | 1000–1050°C |
| 4 | Temperature at the outlet of the sulfur burning furnace | °C | ≤1025°C |
| 5 | SO2 concentration at the outlet of the sulfur burning furnace | % | 9–10.5% |
| 6 | Moisture content in dry air | g/Nm3 | <0.1 |
| 7 | Temperature of the flue gas at the boiler inlet | °C | ≤1025°C |
| 8 | Pressure in the boiler drum | Mpa | 3.40–3.82 |
| 9 | Temperature of the flue gas at the inlet of Air Exchanger No. 2 | °C | 560–580°C |
| 10 | SO2 concentration at the inlet of Stage 1 | % | 9–10.5% |
| 11 | Temperature of the gas entering the catalyst in Stage 1 | °C | 415–420°C |
| 12 | Temperature of the gas exiting the catalyst in Stage 1 | °C | 595–620°C |
| 13 | Temperature of the gas entering the catalyst in Stage 2 | °C | 440–445°C |
| 14 | Temperature of the gas exiting the catalyst in Stage 2 | °C | 505–525°C |
| 15 | Temperature of the gas entering the catalyst in Stage 3 | °C | 440–445°C |
| 16 | Temperature of the gas exiting the catalyst in Stage 3 | °C | 465–485°C |
| 17 | Temperature of the gas entering the catalyst in Stage 4 | °C | 415–420°C |
| 18 | Temperature of the gas exiting the catalyst in Stage 4 | °C | 440–460°C |
8. Analysis items:
- No. 1: Moisture content in the air entering the furnace; sampling point: air inlet of sulfur burning furnace; frequency: once per day
- No. 2: SO2 concentration at the inlet of Stage 1; sampling point: inlet of Stage 1; frequency: once per shift
- No. 3: SO2 concentration at the exit of Stage 3; sampling point: exit of Stage 3; frequency: once per shift
- No. 4: First-stage conversion rate
- No. 5: SO2 concentration at the exit of Stage 4; sampling point: exit of Stage 4; frequency: once per shift; Second-stage conversion rate
III. Process parameters for the dry absorption unit:
| Parameter | Specified range |
|-----------|-----------------|
| Moisture content in the gas exiting the drying tower | <0.1 g/Nm3 |
| Temperature of the gas entering the absorption tower | 170–180°C |
| Acid mist in the gas exiting the drying tower | <0.03 g/Nm3 |
| Acidity of the acid in the drying tower | 98–98.5% |
| Acidity of the acid in the absorption tower | 98–98.5% |
| Absorption efficiency | >99.95% |
| Temperature of the acid in the drying tower | <65°C |
| Liquid level in the circulation tank | 60–70% |
| Temperature of the acid in the absorption tower | 70–80°C |
| Concentration of the final sulfuric acid product | >98% |
IV. Process parameters for the circulating water system:
1. Temperature of water entering the tower: 38–40°C
2. Temperature of water exiting the tower: 28–30°C
3. Volume of cooling water used: 1500–3000 m3/h
4. pH value of circulating water: ≥7.5
5. Suspended solids in circulating water: ≤50 mg/L
6. Temperature of pump bearings: ≤75°C V.1. Anodic protection control parameters (see Table 1) Table 1: Parameters Dry acid Absorbed acid Remarks Acid concentration (%): 93±0.5% 98±1% Outlet water temperature (°C)
Purity, iron content, magnesium content, copper content, phosphorus content, sulfur content