In the energy and chemical industries, bituminous coal stands as the most widely distributed and versatile coal type, with its deep processing and utilization always at the forefront of industrial attention. Whether used for blast furnace injection, thermal power generation, or coking coal blending, processing raw coal into fine powder is a critical step. This article delves into the definition and characteristics of bituminous coal, its global and Chinese resource distribution, main application scenarios, and focuses on analyzing the core processes of high-efficiency bituminous coal grinding mills in modern industry, helping you comprehensively understand the industrial chain logic behind this key equipment.
Bituminous coal is a category with a higher coalification degree than lignite but lower than anthracite, belonging to medium-rank coal. In coal classification standards, its volatile matter in dry ash-free basis is usually more than 10%, and its higher heating value in moist ash-free basis is more than 24 MJ/kg. Physically, bituminous coal ranges from grayish-black to black, with a surface luster varying from asphalt luster to diamond luster, and distinct banded structure.
The most intuitive combustion characteristic of bituminous coal is its long and smoky flame, hence the name "bituminous". Its cohesiveness varies greatly: some have weak cohesiveness, while others exhibit strong cohesiveness (such as fat coal and coking coal). The carbon content of bituminous coal is generally between 75% and 90%, with a high heating value, usually 27170-37200 kJ/kg.
As a versatile mineral resource, bituminous coal is mainly used in the following fields according to its volatile matter and cohesiveness:
Bituminous coal with medium volatile matter and good cohesiveness (such as coking coal, fat coal, lean coal) is the core raw material for coking. After being ground to a specific fineness by bituminous coal grinding mills, bituminous coal is blended in a certain proportion and dry-distilled under isolated air conditions to produce high-strength metallurgical coke, which is widely used in steel smelting.
Bituminous coal with weak cohesiveness such as long-flame coal and lean coal is mainly used as power fuel. In thermal power plants, bituminous coal is ground into fine powder by bituminous coal grinding mills and sent to the boiler for combustion through injection devices. The characteristics of long flame and high heating value of bituminous coal can effectively improve boiler thermal efficiency. Data shows that power coal accounts for more than 70% of China's thermal power generation.
Specific bituminous coal varieties can also be used as raw materials for coal gasification to produce coal gas or syngas, which is used for chemical synthesis or industrial gas, providing important support for the development of clean energy and chemical industry.
Anthracite and some lean coal with low volatile matter can be ground into ultra-fine powder by high-efficiency bituminous coal grinding mills to replace part of the coke injected into the blast furnace, reducing ironmaking costs and improving blast furnace smelting efficiency.
In current industrial applications, there are two main types of high-efficiency equipment for bituminous coal grinding:
Vertical Coal Mill (Medium-Speed Mill): It is the mainstream choice for bituminous coal grinding in power plants and cement plants at present. It integrates drying, grinding, classification and transportation functions.
Working Principle: Raw coal falls through the downcomer to the center of the rotating grinding disc, enters the roller track under centrifugal force, and is crushed by the tire-shaped grinding roller. Hot air enters from the air ring, dries the ground material and sends it to the upper classifier. Qualified fine powder enters the finished product bin with the air flow, and coarse powder falls back to the grinding disc for re-grinding.
Advantages: This bituminous coal grinding mill system has low power consumption and small floor area. Due to the adoption of hydraulic pressurization, the grinding force can be adjusted in real time, adapting to bituminous coal with different grindability.
HCM, a leading Chinese manufacturer of industrial grinding equipment, has advanced technology, excellent product quality and rich experience in clean coal processing. Its HLM series vertical coal mills for bituminous coal have been well-received in the market, with significant advantages:
Explosion-Proof Design: Bituminous coal has high volatile matter, and if the powder concentration and oxygen concentration reach critical points during grinding, there is a risk of explosion. Therefore, all HCM bituminous coal grinding mills are equipped with explosion-proof valves on the shell and adopt inertization protection measures (such as nitrogen filling or outlet temperature control). The outlet air temperature after grinding is strictly controlled at 80-95°C to ensure safety.
Integrated Drying and Grinding: The external and internal moisture of bituminous coal needs to be removed. The high-efficiency bituminous coal grinding mill introduces a hot air furnace, with the inlet air temperature up to 450°C. Bituminous coal is dried while being ground, ensuring the finished product moisture is less than 1%, meeting the quality requirements of different application scenarios.
Online Maintenance and Wear Resistance: Pyrite (iron sulfide) in bituminous coal has high hardness, causing severe wear on grinding rollers and liners. The roller sleeves of HCM bituminous coal grinding mills are made of high-chromium wear-resistant materials and can be used on both sides, greatly extending the service life of equipment and reducing maintenance costs.
As a professional Chinese manufacturer of bituminous coal grinding equipment, HCM is committed to providing high-efficiency, safe and energy-saving grinding solutions for global energy and chemical industries, supporting the sustainable development of the industry with advanced technology and reliable products.
If you require technical solutions for HCM coal mills, production capacity parameters for pulverizers, or quotation plans, please feel free to contact us.
contacts：Engineer Yao，e-mail:[email protected],[email protected] Wechat：18878317068
