Titanium Venturi

System Overview:

In steel mills, the Titanium Venturi system is used to concentrate waste acid from the pickling unit by using heat from the roasting furnace exhaust gases. This process allows for efficient waste acid management and recycling. The concentrated waste acid is then used in the roasting furnace for further processing. Additionally, the system involves a Dust Collector/Separator and a Spray Lance for effective acid delivery and particle management.

1. Titanium Venturi (Pre-Concentrator)

Function:
The Titanium Venturi serves as a pre-concentrator, pumping the waste acid from the pickling unit to the top for spraying. It uses direct heat exchange with the combustion furnace's exhaust gas (395°C) to evaporate water from the waste acid, concentrating it before sending it to the roasting furnace.

Key Parameters:

Diameter: 700 mm

Height: 610 mm

Housing Material: Titanium-Palladium Alloy GR7

Immersion Tube Material: Titanium-Palladium Alloy GR7

Medium Composition:

Liquid Phase (Waste Acid):

HCl: 50-170 g/L

FeCl₂: 350-410 g/L

FeCl₃: 30-70 g/L

Temperature: 95-100°C

Gas Phase (Combustion Exhaust Gas):

HCl steam, water vapor, nitrogen, carbon dioxide, oxygen

Iron oxide powder

Import Temperature: 380-460°C

Export Temperature: 83-95°C

Advantages:

Simple and reasonable structure

Short manufacturing cycle

Convenient installation and long-term maintenance

Stable operation

2. Spray Lance for Roaster

Function:
The Spray Lance is used to spray the waste acid concentrated by the pre-concentrator into the roasting furnace, where it undergoes further heat treatment and decomposition.

Main Parameters:

Nozzle Tube Length: 3170 mm

Nozzle Tube Diameter: Ø33/Ø52 mm

Nozzle Tube Pressure: 460-500 KPa

Nozzle Tube Hose: DN25, L=2600 mm

Nozzle Plate Diameter: Ø152 mm

Nozzle Flow Rate: 3.5 L/min (0.4 MPa)

Number of Nozzles: 11–13 per Nozzle Tube

Plug Quantity: 2-3

Main Materials:

Nozzle Tube: Titanium-Palladium Alloy / Niobium

Nozzle Plate: Titanium-Palladium Alloy / Niobium

Nozzle Tube Casing: Titanium GR7

Nozzle Tube Hose: EPDM / Stainless Steel Wire Mesh / PTFE

Filter Holder: Titanium-Palladium Alloy / Niobium

3. Dust Collector / Separator

Function:
The Dust Collector is responsible for separating Fe₂O₃ particles from the reaction gas in the roasting process and sending them back to the roaster. It also serves as a scrubber for washing out HCl and Fe₂O₃ in the flue gas.

Main Parameters:

Imported Flue Gas Velocity: 15-20 m/s

Separation Efficiency: 50%

Structural Form: One-piece structure

Main Material: Titanium GR7

Functionality of the Scrubber:

The scrubber washes out HCl and Fe₂O₃ from the flue gas to ensure that exhaust emissions meet environmental standards.

Process Overview:

1. Pre-Concentration of Waste Acid:
   The waste acid from the pickling unit is sprayed into the top of the Titanium Venturi where it undergoes heat exchange with the furnace gas. This process evaporates the water from the waste acid, increasing its concentration.

2. Acid Transfer to Roasting Furnace:
   The concentrated waste acid is then transferred to the roasting furnace via the Spray Lance. The waste acid is sprayed into the furnace where it undergoes further thermal treatment.

3. Separation of Iron Oxide (Fe₂O₃):
   The heat in the roasting furnace causes the decomposition of FeCl₂ and FeCl₃, resulting in Fe₂O₃ solid particles. These are separated from the gas stream by the Dust Collector, and the particles are returned to the furnace for further processing.

4. Exhaust Gas Treatment:
   The Dust Collector also helps in washing the HCl and Fe₂O₃ from the flue gas. The cleaned exhaust is then released in compliance with emission standards.

Advantages of Using Titanium-Palladium Alloy GR7:

Corrosion Resistance: Excellent resistance to corrosion in aggressive environments, including exposure to HCl, H₂SO₄, and H₃PO₄, making it ideal for acid regeneration processes in steel mills.

Thermal Stability: Withstands high temperatures (up to 395°C for furnace gas) and ensures durability in high-temperature environments.

Lightweight: The use of titanium ensures that the equipment is lighter and easier to install, while still maintaining excellent strength and resistance to chemical degradation.

Recommendations for Operation and Maintenance:

1. Regular Inspection: Ensure that the Titanium Venturi, Spray Lance, and Dust Collector are inspected periodically for signs of corrosion or wear, especially in areas exposed to high-temperature exhaust gases or concentrated acids.

2. Pressure and Flow Rate Checks: Regularly check the pressure in the nozzle tubes and the flow rates of the spray lance to ensure efficient operation.

3. Cleaning and Maintenance: The titanium components should be cleaned regularly to avoid the build-up of acid or iron oxide residues, which could affect the efficiency of the acid concentration and separation processes.

4. Environmental Monitoring: Monitor emissions from the Dust Collector to ensure that exhaust gases meet regulatory standards.

Summary of Equipment Specifications: