Innovation in seamless steel pipe production process, the secret of reducing energy consumption by 30%

As a key material in the fields of oil,natural gas,and machinery manufacturing,the energy consumption problem in the production process of seamless steel pipes has long plagued the industry.According to statistics,the energy consumption of traditional hot-rolled seamless steel pipe production accounts for 25%-40%of the total cost of the enterprise,and steel pipe production accounts for as much as 15%of the global steel industry's carbon emissions.Driven by the dual goals of"dual carbon"and cost pressure,in 2023,many leading domestic companies will achieve a breakthrough of 30%reduction in energy consumption through technological innovation.Behind this"green revolution"is the deep integration of process optimization,equipment upgrades and intelligent technologies.

1.Energy consumption pain points of traditional processes

1.1 Energy Black Hole of Hot Rolling Process

The core process of traditional hot-rolled seamless steel pipe includes:

Ring furnace heating:the billet needs to be heated at a high temperature of more than 1200℃for 2-3 hours,and fuel consumption accounts for 60%of the total energy consumption

Piercing-rolling-sizing:During the multi-pass deformation process,the heat energy loss rate is as high as 40%.

Cooling system:The energy utilization rate of water cooling and air cooling is less than 50%

Taking a steel pipe plant with an annual output of 500,000 tons as an example,the annual natural gas consumption in the heating stage alone reaches 120 million cubic meters,equivalent to the emission of 300,000 tons of CO₂.

1.2 Efficiency bottleneck of cold rolling process

Although cold-rolled seamless steel pipes can reduce heating energy consumption,they have the following problems:

-Work hardening leads to a 30%increase in mill power requirements

-Annealing process still needs to be repeated heating to 700-800℃

-Chemical consumption in surface treatment increases overall energy consumption

2.Three core breakthroughs in technological innovation

2.1 Energy-saving transformation of hot rolling process

(1)Medium frequency induction heating technology replaces ring furnace

Principle:Rapid heating of the blank interior through electromagnetic induction

Advantages:

-Heating time reduced from 3 hours to 20 minutes

-Thermal efficiency increased from 45%to 85%

-Precise temperature control reduces oxidation and burning(loss rate reduced from 2.5%to 0.8%)

Actual measured data from a steel plant showed that after adopting this technology,natural gas consumption per ton of steel dropped from 120m³to 65m³,with an energy saving rate of 46%.

(2)Innovation of multi-stand continuous rolling process

-Change the traditional single-stand reciprocating rolling to 4-stand continuous rolling

-Rolling passes reduced by 50%and rolling forces reduced by 35%

-With the hydraulic AGC(automatic thickness control)system,the thickness tolerance is controlled within±0.15mm

2.2 Intelligent Upgrade of Cold Rolling Technology

(1)AI-driven rolling parameter optimization

-Analyze historical data through machine learning algorithms and dynamically adjust:

-Roller reduction(accuracy±0.01mm)

-Rolling speed(matching material deformation resistance curve)

-Lubricant injection quantity(to reduce friction energy loss)

A pilot project showed that the system can reduce electricity consumption in cold rolling by 18%.

(2)Laser annealing replaces traditional heat treatment

-Local annealing using 3000W fiber laser

-Energy consumption is only 1/5 of that of resistance furnace,and processing time is shortened by 70%

-Grain size control accuracy is improved to ISO 643 standard level 10

2.3 Revolutionary Innovation of Waste Heat Recovery System

(1)Four-level waste heat cascade utilization system

|Waste heat source|Temperature range|Recovery technology|Utilization methods|

|Rolling cooling water|80-120℃|Absorption heat pump|Plant heating/pretreatment heating|

|Waste gas|400-600℃|Heat pipe heat exchanger|Power generation(ORC unit)|

|Waste heat from steel pipe surface|200-300℃|Radiation recovery device|Preheating of billets|

|Cooling steam|150-180℃|MVR mechanical recompression|Desalinated water preparation|

A certain enterprise has achieved a comprehensive waste heat utilization rate of 92%through this system,saving 18,000 tons of standard coal annually.

(2)Energy management driven by digital twins

-Build an IoT platform covering 2000+sensors

-Real-time monitoring of energy consumption hotspots in each process

3.Typical case:Transformation practice of a leading enterprise

3.1 Energy consumption baseline before renovation

-Annual production of 800,000 tons of seamless steel pipes

-Comprehensive energy consumption per ton of steel:580kgce/t

-Annual carbon emissions:920,000 tons of CO₂equivalent

3.2 Technical Implementation Path

1.**Phase 1(6 months)**:

-Ring furnace converted into induction heating unit

-Install waste heat power generation ORC system

2.**Phase 2(12 months)**:

-Deployment of AI rolling optimization system

-Build a digital energy management center

3.3 Results after transformation

|Indicators|Before renovation|After renovation|Decrease|

|Energy consumption per ton of steel(kgce/t)|580|406|30%|

|Natural gas consumption(m³/t)|135|82|39.3%|

|Electricity consumption(kWh/t)|320|235|26.6%|

|Annual emission reduction(10,000 tons CO₂)|-|25.6|-|

4.Industry Enlightenment and Future Outlook

4.1 The economics of technology promotion

-Take a steel plant with an annual output of 500,000 tons as an example:

-The renovation cost is about 230 million yuan

-Annual energy saving benefits of 110 million yuan(calculated based on electricity price of 0.6 yuan/kWh and gas price of 3.5 yuan/m³)

-Investment payback period is approximately 2.1 years

4.2 Technical Difficulties to be Solved

1.Uniform heating control of super large diameter steel pipes(Φ≥600mm)

2.Energy consumption optimization in extreme environments(such as-50℃low temperature rolling)

3.Exploration of commercial application of hydrogen heating furnace

4.3 New global competition landscape

-German SMS Group launches the"Hybrid Mill"concept,with the goal of reducing energy consumption by 40%

-Japan's JFE has developed microwave-assisted rolling technology,reducing rolling force by 28%

-China Baosteel's"Smart Steel Pipe Factory"project has achieved unmanned production throughout the entire process

Conclusion:From energy efficiency revolution to green competitiveness

The 30%reduction in energy consumption in seamless steel pipe production is not only a breakthrough in technical parameters,but also marks the transformation of China's manufacturing industry from"scale expansion"to"quality leap".With the in-depth application of technologies such as digital twins and AI predictive maintenance,the industry is expected to achieve a further 15%-20%reduction in energy consumption in the next five years.This green revolution is reshaping the competition rules of the global steel pipe industry-whoever masters the core energy-saving technology will dominate the market structure in the next decade.