Cradle to Gate
Identity ID
dd287b59-182e-4f6d-acbf-dfb7ff3e4995
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) of the process from dense middlings coal preparation to the output of coking Middlingss, covering all activities associated with coal washing, but excluding external conditions beyond the coal preparation plant (such as raw coal mining and the use of clean coal), as well as direct or indirect greenhouse gas emissions from employee commuting and daily office operations during the coal washing process. The dataset is based on national standards such as 'Cleaner Production Standard for the Coal Mining and Preparation Industry' (HJ 446-2008) and 'Emission Standards of Pollutants for the Coal Industry,' and has been compiled from multiple data sources to represent the average production level in Shanxi.
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 in Shanxi Province is widely distributed in the Taiyuan Formation and Shanxi Formation. The Taiyuan Formation includes gas coal, fat coal, coking coal, lean coal, and gas-fat coal, while the Shanxi Formation includes gas coal, fat coal, coking coal, and lean coal. The raw coal ash content of the Taiyuan Formation ranges from 6.95% to 37.97%, volatile matter from 9.6% to 41.01%, maximum thickness of the plastic layer from 0 to 40 mm, total sulfur from 0.68% to 5.97%, and Qnet,ar (gross calorific value on an as-received basis) from 7712 to 9078 kcal/kg. The raw coal ash content of the Shanxi Formation ranges from 16.53% to 34.33%, and volatile matter from 13% to 40%. 0.3%, with a maximum thickness of the vitrinite layer ranging from 0 to 75 mm, and a net calorific value on an as-received basis (Qnet,ar) of 7,400–8,660 kcal/kg. The middlings in coking coal are intermediate products between clean coal and gangue. The middlings in coking coal generally have relatively high ash content, possibly reaching around 25%–40%. Their caking and coking properties are inferior to those of Coking clean coal. Middlings from coking coal are generally unsuitable for the production of high-quality coke, as their higher impurity content can negatively affect coke quality indicators such as strength and pore structure. However, in some applications with slightly lower coke quality requirements or after special treatment, coking Middlingss can be partially used to produce coke, or utilized for other industrial combustion purposes, such as being used as a fuel in industrial boilers. However, the impacts of harmful components such as sulfur content on the environment and equipment must be considered.
Time period
2022
2026
Geography
China,Shanxi
Geography comment
Forming Shanxi'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.