Cradle to Gate
Identity ID
a491599c-9018-49ac-a569-1c130d478dae
Materials
Associated ID
de8bb2a5-b593-449a-bf48-325b1a8a0b9e
Included activities starts
Included activities ends
Description
This dataset represents a life cycle inventory (cradle-to-gate) for the production of coking middlings starting from dense middlings coal preparation, covering all activities associated with coal washing, but excluding scenarios external to the coal preparation plant (such as raw coal mining and the utilization of Clean coal), as well as direct or indirect greenhouse gas emissions from personnel commuting and daily office operations during the coal washing process. The dataset is developed by synthesizing data from multiple sources, in accordance with Chinese national standards such as the "Cleaner Production Standard for the Coal Mining and Preparation Industry" (HJ 446-2008) and the "Emission Standards for Pollutants from the Coal Industry," and is representative of the average production level in China.
Activity Description
This dataset describes heavy medium coal beneficiation, a method that uses a heavy medium suspension to separate coal from impurities. The specific process is as follows:
Coal crushing:
Raw coal is crushed by a crusher into particles suitable for washing, typically below 50 mm. The crushed coal then enters screening equipment for particle size classification.
Preparation of heavy medium suspension:
Magnetite powder or other heavy medium materials are mixed with water to prepare a heavy medium suspension of a specific density. The density of the suspension is adjusted according to the density difference between coal and impurities.
Coal separation:
The crushed coal enters the heavy medium separator. In the suspension, coal with lower density floats while impurities with higher density sink, enabling separation of coal and impurities. The separated light fraction (coal) and heavy fraction (impurities) are discharged through different outlets.
Recovery of dense medium:
The dense medium suspension after separation is processed through a magnetic separator to recover magnetite powder, which is then recycled. The recovered dense medium materials are returned to the preparation stage.
Dewatering:
The separated coal contains a certain amount of moisture and is treated by dewatering equipment such as dewatering screens and centrifuges to reduce moisture content and increase the calorific value of the coal.
Storage and transportation:
After dewatering, the coal is stored and transported. To prevent coal from moisture absorption and spontaneous combustion during storage and transportation, protective measures should be taken, such as using coal sheds or enclosed stockyards for storage.
Process Description
Coking coal is a type of coal used for producing high-quality coke in coking processes, and its quality and properties directly affect the coking process and the quality of the resulting coke. The middlings of coking coal are intermediate products between clean coal and gangue. The ash content of coking Middlingss is relatively high, possibly reaching about 25%–40%. Its caking and coking properties are inferior to those of Coking clean coal. Coking Middlingss are generally not suitable for the production of high-quality coke, as their higher impurity content can negatively affect quality indicators such as coke strength and pore structure. However, in some applications where coke quality requirements are slightly lower, or after special treatment, coking Middlingss can be partially utilized for coke production or used for other industrial combustion purposes, such as a fuel for industrial boilers. However, the impact of harmful components such as sulfur content on the environment and equipment must be considered.
Time period
2022
2026
Geography
China
Geography comment
Forming China's average data through merging data from multiple sources.
Macroeconomic value
Business-as-Usual
Data validation
Yes
Technology
Current Technology
Technology comment
Heavy middlings coal beneficiation is an effective coal cleaning method primarily used to improve coal quality. This method employs a liquid medium with a density between that of coal and gangue for separation. The separation media used include heavy liquids and suspensions. Currently, both domestically and internationally, suspensions prepared by mixing magnetite powder with water are widely used as the separation medium in coal beneficiation. Heavy middlings coal beneficiation involves several steps, including coal crushing, preparation of the heavy middlings suspension, coal separation, recovery of the heavy middlings, and dewatering processes.