| Autor: |
Terry Wall, I.McC. Stewart |
| Rok vydání: |
1977 |
| Předmět: |
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| Zdroj: |
Scopus-Elsevier |
| ISSN: |
0082-0784 |
| DOI: |
10.1016/s0082-0784(77)80349-4 |
| Popis: |
Performance is reported for quasi-steady state computational models of two zones of borehole type in-situ gasification systems. The plug-flow reduction zone is a close replica of real systems; the well-stirred reactor models some special systems and may be indicative of a wide range of ignition zone conditions. For both models it is postulated that seam moisture evaporation and coal devolatilization occur at some distance (inversely proportional to the advance rate) behind a reacting face of coke and that reaction of these products with coke occurs behind the face. This model produces an apparent reactivity for the system more strongly dependent on seam moisture and volatile content than on the chemical reactivity of the coke. Computations predict that gasification efficiency and combustion stability are sensitive to an optimal combination of seam moisture and of blast moisture. These findings and the predicted gas analyses and efficiencies are generally in line with what published field information is available. The advantageous effect of high moisture content in the gas is to increase reaction rate (by increasing the concentration of a major reactant); this is balanced by the temperature drop due to added heat capacity. The overall effect is so dramatic as to warrant this type of analysis before completing design for field experiments. Laboratory testing on large samples of seam coal is advisable to test the model for detail and obtain better rate coefficients. It is predicted that high ratings and high gasification efficiencies are possible for oxygensteam gasification either in plug-flow or W.S.R. systems, particularly if preheat can be achieved. |
| Databáze: |
OpenAIRE |
| Externí odkaz: |
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