Pilot-scale Carbonization

Process overview

The pilot-scale coke-making process is complex, requiring a thorough understanding of the process to achieve sensible outcomes. A generalized process overview is provided below:

• During preparation of a coke oven change, the particle size distribution, moisture concentration are adjusted to achieve a target bulk density in the coke oven.
• Prior to charging the oven, the oven wall temperatures are adjusted to a start temperature, typically more than 800°C. Once the coal has been inserted into the oven, the wall temperatures are increased at a set constant rate aimed at mimicking the heating rate in industrial coke oven processes.
• During coke-making, the temperature and gas pressure in the center of the charge is continuously measured via probes inserted into the charge immediately after charging
• The coked product is discharged from the coke oven one hour after the center of the charge has attained 1010°C. The coke is quenched with water and dried in a fan-forced oven set at 110°C
• The dry coke is then weighed, stabilized and sized through a nest of screens. This provides information on coke yield and mean coke size
• The coke is then sub-sampled for analysis. Typical analyses include: Coke Reactivity Test (CRI, CSR), ASTM Tumbler Test (ASTM 1” Stability and ASTM ¼" Hardness), Micum Drum Test (M40, M10), Irsid Drum Test (I40, I20, I10), JIS Indices (DI13015, DI15015) and Coke Porosity. The test-work may also include routine coke analytical tests such as Proximate Analysis, Total Sulfur and Ash Chemistry

Control systems

During preparation of the sample for coke-making, all data is captured by ALS’ in-house laboratory information management system. This system is connected to all balances to ensure a there is a fully visible and auditable process. During coke-making, the oven wall temperatures are controlled by cRIO data management and data logging system controlling 6 solid state thyristors which in turn control 12 SiC elements per oven. Data from the pressure transducers, which measure internal gas pressure, and load cells, which measure wall force, along with wall and center temperatures, are captured by the cRIO data logging function. During coke testing, all data is again captured by the laboratory information management system. Coke analysis is typically tested as duplicates, with results falling outside standard repeatability limits being re-tested.

Laboratory support

Comprehensive coal characterization is typically required on the feed coal. This is typically sub-sampling prior to coke-making and processing the coal through ALS’ extensive laboratory network.