A Permeation Theory for In-Situ Coal Gasification

Abstract

A permeation tbeo~, of insitu coal gasificationis developed, and a mathematical model is derived for the process, Predicted gas compositions, gas fiow rates, and temperature pro/iles are in good agreement with /ieid test data, For example, experimental gas compositions deviate no more than 3 to 4 molYa from calculated values, On the average, agreement is much better. The major purpose oi the permeation theory is to provide a basis for quantitative understanding of in-situ coal gasification and to lead to important ,yeneral conclusions concerning the nature of !be process. The well instrumented Hanna 2, Phase 2 test was essential in providing needed information to coniirm the theoretical conclusions. This test was conducted near Hanna, WY, during 1976 and was the best instrumented and most succ~ss~ul /ield test ever conducted up to that time.

Underground coal gasification: Development of theory, laboratory experimentation, interpretation, and correlation with the Hanna field tests: Final report

“…In all cases, there is good agreement between experimental and calculated results with maximum deviations on the order of 3 to 4 mole percent except for carbon dioxide. Gunn, Fischer and Whitman (1978) also carried out a parametric study of the model used. Any realistic model for UCG must contain a number of temperature dependent properties of ash, coal char and coal such as heat capacity, thermal conductivity, density, devolatilization characteristics and react1 on rate constants.…”

“…Certain well formed temperature profiles, however, can be analyzed on the basis of assumed local conditions. A detailed analysis of two such temperature profiles has been reported by Gunn, Fischer and Whitman ( 1978). While true predictive capability is not present because of the necessity to assume local conditions, the analysis has considerable educational value because specific processes 1 eadi ng to the formation of the profile can be identified.…”

“…Agreement was good, however, this test was less thoroughly instrumented than subsequent tests; and data from the Hanna II Phase I test is less accurate. OnlyTable III-1 is reproduced here from the report cited Gunn, Whitman and Fischer (1978). reported the comparison of calculated and experimental data for the Hanna II Phase II field test.…”

Economic sensitivity study of UCG based on field performance, theory, and operational experience

“…elsewhere. (24,25) Theoretical models are especially helpful in determining parameter interdependencies which might otherwise go undetected. An unexpected relationship is the dependence of the gas/air ratio on.…”

Pengaruh Panjang Zona Gasifikasi Batubara Bawah Tanah Terhadap Komposisi Gas Hasil (Effect of Zona Length of an Underground Coal Gasification to the Gas Product Composition)

“…Meskipun demikian perlu disadari bahwa masih banyak faktor-faktor lainnya yang perlu diperhatikan seperti misalnya lokasi awal penyalaan; alur gasifikasi yang sebaiknya diusahakan agar mulai terjadi dibagian bawah lapisan batubara; permeabilitas lapisan batubara, jenis batubara; kondisi devolatilisasi batubara; reaktifitas dll. (Gunn, 1978).…”