What is the energy consumption of the graphitization process for graphitized petroleum coke?

The graphitization process of graphitized petroleum coke is a typical high-energy-consuming production link, with its energy consumption characteristics and key influencing factors outlined as follows:

I. Core Energy Consumption Data

1. Gap Between Theoretical and Actual Power Consumption When the graphitization temperature reaches 3,000°C, the theoretical power consumption for one ton of baked products is 1,360 kWh. However, in actual production, domestic enterprises typically consume 4,000–5,500 kWh per ton, which is 3–4 times the theoretical value. For example, a large carbon plant producing 100,000 tons of graphite electrodes annually consumes 3,000–5,000 kWh per ton during the graphitization stage, highlighting significant energy pressure. 2. Cost Proportion In the production of artificial graphite anode materials, graphitization costs account for approximately 50% of the total cost, making it a key area for cost reduction. Electricity expenses constitute over 60% of the total graphitization cost, directly determining the process’s economic efficiency.

II. Analysis of High Energy Consumption Causes

1. Fundamental Process Requirements Graphitization requires high-temperature heat treatment (2,800–3,000°C) to transform carbon atoms from a disordered layered structure into an ordered graphite crystal structure. This process necessitates continuous energy input to overcome interatomic resistance, resulting in inherently high energy consumption.

2. Low Efficiency of Traditional Processes

• Acheson Furnace: The mainstream method, but with only 30% thermal efficiency, meaning only 30% of electrical energy is used for graphitizing products, while the remainder is wasted through furnace heat dissipation and resistor material consumption.
• Long Power-On Cycles: Single-furnace power-on durations range from 40–100 hours, with production cycles lasting 20–30 days, further escalating energy consumption. 3. Equipment and Operational Constraints
• Furnace core current density is limited by power supply capacity. Increasing current density can shorten power-on time but requires equipment upgrades, raising investment costs.
• Temperature rise rates are constrained to prevent product cracking from thermal stress, limiting optimization space for energy consumption reduction.

III. Advances and Effects of Energy-Saving Technologies

1. Application of New Furnace Types

• Internal Series Graphitization Furnace:Principle: Directly heats electrodes without resistor materials, reducing heat loss.Effect: Reduces power consumption by 20%–35% and shortens heating time to 7–16 hours.
• Box-Type Furnace:Principle: Divides the furnace core into multiple chambers, with anode materials placed in conductive graphite-lined boxes that self-heat when powered.Effect: Increases single-furnace effective capacity, raises total power consumption by only ~10%, lowers unit power consumption by 40%–50%, and eliminates resistor material costs.
• Continuous Furnace:Principle: Enables integrated continuous production (loading, powering, cooling, unloading), avoiding heat loss from intermittent furnace operation.Effect: Cuts energy consumption by ~60%, significantly shortens production cycles, and enhances automation. 2. Process Optimization Measures
• Improved furnace insulation structures to minimize heat loss and enhance thermal efficiency.
• Development of efficient thermal field designs for uniform temperature distribution and reduced energy use.
• Smart temperature control systems featuring multi-zone monitoring and intelligent algorithms for precise heating curve management, preventing energy waste.

IV. Industry Trends and Challenges

1. Capacity Relocation Graphitization capacity is concentrating in northwest China, leveraging low local electricity prices to reduce costs. For instance, Inner Mongolia accounts for 47% of national graphitization capacity, becoming a primary production hub. 2. Policy-Driven Technological Upgrades Under “dual control” energy consumption policies, high-energy graphitization capacity faces restrictions, compelling enterprises to adopt energy-saving processes. Firms with integrated production capabilities (e.g., self-supplying graphitization) gain competitive advantages, accelerating market consolidation toward leading players. 3. Risk of Technological Substitution While continuous furnaces and other novel technologies offer significant energy savings, their high equipment costs and technical barriers hinder rapid replacement of traditional Acheson furnaces. Enterprises must balance technology upgrade investments against long-term benefits.