Weekly Topic: What are the principles guiding the selection of raw coal for water-coal slurry gasification?

1. Due to the limitations imposed by the refractory brick lining in terms of resistance to high temperatures and slag, it is generally required that the ash melting point of coal be at T4 in a reducing atmosphere

Reply to 2# jensse: If the grindability index (HGI) of the raw coal is high, then what should the Haas grindability index be – above 70?

Reply to 3# rhinocao: 60 is sufficient for water-coal slurry, while 70 is required for petroleum coke

Reply to 2# jensse: To add something, regarding the ash content of the raw coal, experience from the Wei River suggests that it should be less than 12%.

1. Volatile matter. It is best to be above 25% for easier combustion. 2. Ash content. It is best to be less than 13%. As the experts mentioned earlier, for every 1% increase in ash content, oxygen consumption increases by about 0.7%-0.8%, while coal consumption increases by about 1.3%-1.5%. 3. Ash melting point. The flow temperature should preferably be below 1350 degrees. Otherwise, more flux must be added, which leads to increased energy consumption and greater wear. 4. The ash should have good viscosity-temperature properties. To ensure stable slag discharge and provide greater operational flexibility. 5. Internal water. In particular, the internal water content should preferably be below 8%-10% to facilitate the production of high-concentration coal slurry. 6. HGI. The Haas grindability index should ideally be above 70, to reduce coal grinding power consumption and facilitate the production of high-quality coal slurry. 7. Calorific value. The higher the calorific value, the better. 8. Sulfur content. It’s relatively less. Of course, if a sulfur-resistant shift reaction is used in the subsequent process, it is sometimes necessary to maintain a certain sulfur content. 9. The lower the levels of halogens such as chlorine and fluorine in the raw coal, the better; otherwise, special attention must be paid to the material selection for equipment and pipelines in the gasification and subsequent systems.

Another thing that is very important is also worth mentioning. Supply source – there must be an adequate supply of coal; don’t end up running out of coal after just a couple of days of production, forcing the use of alternative types of coal...