What kind of coal is suitable for water-coal slurry but not for dry coal powder?
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This post was last edited by captainjn on 2011-12-23 at 13:41. The slurry formation performance is poor; of course, there’s no dispute regarding dry coal powder. High ash fusion point? This is the advantage of dry-powder cold wall furnaces. Low ash fusion point? By lowering the temperature, everyone achieves the same benefit (cold gas efficiency), but the latent heat of vaporization of the coal slurry, which contains 40% water, is still necessary; as a result, the difference in cold gas efficiency remains the same. High calorific value? Can CO2 be added to a dry powder furnace to absorb heat, for low calorific value? The cold gas efficiency of coal-water slurry furnaces is absolutely terrible. High ash content? Both dry powder furnaces and water-coal slurry furnaces use liquid slag discharge, resulting in the same disadvantages. Low ash content? Both dry powder furnaces and water-coal slurry furnaces use liquid slag discharge, and the benefits resulting from this are the same. Oh, using slag to counteract slag might be a problem. This is considered a strength of hot-wall furnaces, so do dry coal powder hot-wall furnaces work well? So, when is it appropriate to use a water-coal slurry furnace? 1. The company is short of funds and needs to reduce investments. 2. The company is concerned about the complexity of operating powder-fired furnaces, or about the immaturity of related technologies. 3. The subsequent processing stages require a high hydrogen-to-carbon ratio, but the company doesn’t want to spend money on major modifications. But isn’t any of this related to the type of coal used? So, which type of coal is suitable for water-coal slurry and not suitable for dry coal powder? I haven’t been able to figure this out; maybe I’ve overlooked some factor. Which expert can give me some advice?
There are various opinions on this issue, which can be summarized in one sentence: expanding the adaptability of coal types. In fact, there is no universal technology; the choice depends on the type of coal. Technologies should be selected based on a company’s financial situation and the type of coal that will be used in the long term. It is not possible to choose the technology first and then decide on the type of coal – generally, the types of coal suitable for slurry coal gasification are also suitable for dry coal powder gasification.
Gasification technology is the choice, and coal quality is the basis and fundamental factor. However, if the coal quality is suitable for both water-coal slurry and dry powder applications, then it depends on the preferences of higher-ups; there are many hidden factors involved in this
Hehe, only technical issues are discussed here. I just realized that, for Shell’s technology, a low ash fusion point is not acceptable either, as ash tends to accumulate over time. It’s not as good as GSP or space furnaces in this regard. Therefore, dry powder gasification cannot be generalized.