Two-stage underground coal gasification was studied to improve the caloric value of the syngas and to extend gas production times.A model test using the oxygen-enriched two-stage coal gasification method was carried o...Two-stage underground coal gasification was studied to improve the caloric value of the syngas and to extend gas production times.A model test using the oxygen-enriched two-stage coal gasification method was carried out.The composition of the gas produced,the time ratio of the two stages,and the role of the temperature field were analysed.The results show that oxygen-enriched two-stage gasification shortens the time of the first stage and prolongs the time of the second stage.Feed oxygen concentrations of 30%, 35%,40%,45%.60%,or 80%gave time ratios（first stage to second stage） of 1：0.12,1：0.21.1：0.51,1：0.64, 1：0.90.and 1：4.0 respectively.Cooling rates of the temperature field after steam injection decreased with time from about 19.1-27.4℃/min to 2.3-6.8℃/min.But this rate increased with increasing oxygen concentrations in the first stage.The caloric value of the syngas improves with increased oxygen concentration in the first stage.Injection of 80%oxygen-enriched air gave gas with the highest caloric value and also gave the longest production time.The caloric value of the gas obtained from the oxygenenriched two-stage gasification method lies in the range from 5.31 MJ/Nm^3 to 10.54 MJ/Nm^3.展开更多
The instrumentation, method and measurement results used for measurements of CO2 concentrations in surface air of Obninsk （55.1° N, 36.9° E, 183 m above the sea level） located at a distance of 105 km to th...The instrumentation, method and measurement results used for measurements of CO2 concentrations in surface air of Obninsk （55.1° N, 36.9° E, 183 m above the sea level） located at a distance of 105 km to the south-west of Moscow are presented. Proposed is a method of experimental data filtering allowing one to separate natural and anthropogenic variations of CO2 concentrations. It is shown that minimal concentrations of CO2 registered in Obninsk and at the continental stations of GAW WMO characterize not only the ＂regional background＂ but also coincide with the data from GAW WMO background stations located in the oceanic regions. In this connection, one can assume that the excess in measured CO2 concentration over its minimal values, making about 5-6 ppm, is connected with an anthropogenic emission, and the continent should be considered as an anthropogenic source of C02.展开更多
基金financial support of the National Natural Science Foundation of China(No.50876112)the Fundamental Research Funds for the Central Universities (No.2009QH13)the Program of International S&T Cooperation (No.2009DFR60180,No.2010DFR60610)
文摘Two-stage underground coal gasification was studied to improve the caloric value of the syngas and to extend gas production times.A model test using the oxygen-enriched two-stage coal gasification method was carried out.The composition of the gas produced,the time ratio of the two stages,and the role of the temperature field were analysed.The results show that oxygen-enriched two-stage gasification shortens the time of the first stage and prolongs the time of the second stage.Feed oxygen concentrations of 30%, 35%,40%,45%.60%,or 80%gave time ratios（first stage to second stage） of 1：0.12,1：0.21.1：0.51,1：0.64, 1：0.90.and 1：4.0 respectively.Cooling rates of the temperature field after steam injection decreased with time from about 19.1-27.4℃/min to 2.3-6.8℃/min.But this rate increased with increasing oxygen concentrations in the first stage.The caloric value of the syngas improves with increased oxygen concentration in the first stage.Injection of 80%oxygen-enriched air gave gas with the highest caloric value and also gave the longest production time.The caloric value of the gas obtained from the oxygenenriched two-stage gasification method lies in the range from 5.31 MJ/Nm^3 to 10.54 MJ/Nm^3.
文摘The instrumentation, method and measurement results used for measurements of CO2 concentrations in surface air of Obninsk （55.1° N, 36.9° E, 183 m above the sea level） located at a distance of 105 km to the south-west of Moscow are presented. Proposed is a method of experimental data filtering allowing one to separate natural and anthropogenic variations of CO2 concentrations. It is shown that minimal concentrations of CO2 registered in Obninsk and at the continental stations of GAW WMO characterize not only the ＂regional background＂ but also coincide with the data from GAW WMO background stations located in the oceanic regions. In this connection, one can assume that the excess in measured CO2 concentration over its minimal values, making about 5-6 ppm, is connected with an anthropogenic emission, and the continent should be considered as an anthropogenic source of C02.
