In the production process of zinc smelting, the treatment of fluorine-containing chlorine fumes
has always been a technical bottleneck restricting the green development of the industry. The
traditional fixed-bed treatment process has low removal efficiency, high risk of secondary
pollution, insufficient metal recovery rate and other pain points, which are being cracked one
by one by the intelligent multi-layer furnace technology. In this paper, we will analyze the
automated transformation of the multi-layer furnace system, how to achieve efficient removal
of chlorofluorine elements and resource recovery through five major technological innovations.
Gradient temperature control system precisely
dissociates compounds
Intelligent temperature control system monitors the temperature distribution of each layer of the
furnace bed in real time through 72 groups of thermocouples, and dynamically adjusts the gas
supply and burner angle by combining with the spectral analysis data of zinc soot composition.
In the critical reaction interval of 600-750°C, the system can control the temperature fluctuation
within ±5°C, ensuring that PbCl, ZnF and other compounds are fully evaporated. After being
applied by a large zinc smelter, the fluorine and chlorine removal rate has increased from 82%
in the traditional process to 96.5%, and the metal residue has been reduced to less than 0.3%.
The embedded infrared imaging module can also capture the melting state of materials in
real time and automatically adjust the residence time of materials to increase the processing
efficiency by 40%.
Intelligent negative pressure network optimizes
gas-solid separation
Negative pressure regulation system constructed based on hydrodynamic model can form
differentiated pressure gradient in different furnace layers. When a sudden change in flue gas
flow is detected, the intelligent damper completes the pressure compensation within 0.8
seconds, ensuring that the volatile chlorofluorocarbons enter the collection pipeline efficiently.
The IoT pressure sensor array achieves a density coverage of 16 monitoring points per square
meter, increasing the system's negative pressure stability to 99.7%. The supporting cyclone
dust collection device is equipped with adaptive infusion blades that automatically adjust
the rotation speed according to the particle size of the particles, making the dust capture
efficiency exceed 98%.
Multiphase flow modeling improves evaporation efficiency
The digital twin platform establishes a three-phase flow model of flue gas-dust-compounds
through Computational Fluid Dynamics (CFD) simulation. Process engineers can simulate the
evaporation path under different raw material ratios in the virtual environment and optimize
the furnace structure parameters. After applying the technology to a renewable zinc project,
the single commissioning cycle was shortened from 45 days to 8 days, and steam energy
consumption was reduced by 33%. Intelligent charging robotic arm with X-ray composition
detector realizes accurate feeding of 12 tons per hour, and elemental burn rate is
controlled within 0.5%.
Closed-loop treatment system realizes near-zero emission
The integrated DCS-controlled environmental protection treatment unit contains three levels
of purification modules: emergency cooling tower, bag dust removal and wet scrubbing.
When the online monitor detects that the concentration of fluoride ions in the tail gas exceeds
15mg/m³, the system automatically starts the standby scrubbing tower and increases the
amount of lye injection to ensure that the emission index is better than the national standard
by 40%. The waste heat recovery device can cool down the 900℃ flue gas to below 150℃,
and the annual recovered heat energy is equivalent to 2,600 tons of standard coal. After the
renovation of a smelter, the annual fluoride emission is reduced by 87 tons, and the
environmental protection operation and maintenance cost is reduced by 55%.
Energy Efficiency Optimization Hub Reduces Operation Costs
The intelligent energy management platform integrates six types of energy data, such as electricity,
gas, steam, etc., and generates the optimal energy consumption program through machine learning
algorithms. It automatically raises the processing load in the valley of electricity price and adjusts
the speed of induced draft fan in real time to save electricity consumption. The actual operation
data shows that the comprehensive energy consumption is reduced by 28%, the peak load is
cut by 35%, and the annual energy cost savings exceeds 4 million yuan. The equipment health
prediction system can warn the rotary kiln bearing failure 72 hours in advance through vibration
spectrum analysis, which reduces the unexpected downtime by 80%.
At present, the intelligent multi-layer furnace technology is reshaping the zinc smelting environmental
treatment system. Through the construction of “precise temperature control - intelligent negative
pressure - efficient evaporation - deep purification” of the whole process solution, not only to
achieve fluorine and chlorine pollutants discharge, but also to make the recovery rate of zinc,
lead and other valuable metals increased to more than 99.2%. Industry monitoring data shows
that the return cycle of environmental protection investment of the production line adopting
the intelligent multi-layer furnace system has been shortened to 2.3 years, and the by-product
revenue has increased by 60%.
With the deep integration of digital twin and artificial intelligence technology, the new generation
of multi-layer furnace is evolving towards autonomous decision-making. The adaptive control
system can automatically optimize process parameters according to fluctuations in raw material
composition, and the 5G edge computing gateway achieves millisecond response latency. Driven
by the goal of “double carbon”, this intelligent equipment integrating clean production and
resource recycling will become the core pillar of green transformation of the non-ferrous metal
industry and provide key technical support for sustainable development.