The release characteristics of CH_(4),H_(2),CO and CO_(2) from iron coke hot briquette(ICHB)during carbonization were studied.The results show that compared with briquette without iron ore,Fe_(3)O_(4) can inhibit the ...The release characteristics of CH_(4),H_(2),CO and CO_(2) from iron coke hot briquette(ICHB)during carbonization were studied.The results show that compared with briquette without iron ore,Fe_(3)O_(4) can inhibit the release rate of H2 and promote the production of CO and CO_(2).In addition,when the heating rate increases from 3 to 7℃/min,the release rates of CH4 and H2 increase,while the release rates of CO and CO_(2) first increase and then decrease.The carbonization process of ICHB was segmented,and corresponding kinetic analysis was carried out.The results show that the activation energy of StageⅡand StageⅣis higher in the carbonization process of ICHB,and the active pyrolysis of coal and the reduction of iron ore occur in these two stages.In addition,the effect of heating rate on the kinetic parameters of ICHB carbonization process was investigated.It was found that when the heating rate increased,the reaction activation energy of StageⅣdecreased first and then increased,which was consistent with the release law of CO and CO_(2).The analysis showed that the increase in heating rate leads to more reactions at higher temperatures,resulting in an increase in the release rate of some gases.In addition,thermal hysteresis can also cause some processes to fail to fully react at the end of heating.It is also found that the apparent activation energy and preexponential factor have kinetic compensation effect during the car-bonization of ICHB.展开更多
The rapid depletion of fossil fuel and growing demand necessitates researchers to find alternative fuels which are clean and sustainable. The need for finding renewable, low cost and environmentally friendly fuel reso...The rapid depletion of fossil fuel and growing demand necessitates researchers to find alternative fuels which are clean and sustainable. The need for finding renewable, low cost and environmentally friendly fuel resources can never be understated. An efficient method of generation and storage of hydrogen will enable automotive manufacturers to introduce hydrogen fuelled engine in the market. In this paper, a conventional DI diesel engine was modified to operate as gas engine. The intake manifold of the engine was supplied with hydrogen along with recirculated exhaust gas and air. The injection rates of hydrogen were maintained at three levels with 2 L/min, 4 L/min, 6 L/min and 8 L/min and 10 L/min with an injection pressure of 2 bar. Many of the combustion parameters like heat release rate (HRR), ignition delay, combustion duration, rate of pressure rise (ROPR), cumulative heat release rate (CHR), and cyclic pressure fluctuations were measured. The HRR peak pressure decreased with the increase in EGR rate, while combustion duration increased with the EGR rate. The cyclic pressure variation also increased with the increase in EGR rate.展开更多
文摘The release characteristics of CH_(4),H_(2),CO and CO_(2) from iron coke hot briquette(ICHB)during carbonization were studied.The results show that compared with briquette without iron ore,Fe_(3)O_(4) can inhibit the release rate of H2 and promote the production of CO and CO_(2).In addition,when the heating rate increases from 3 to 7℃/min,the release rates of CH4 and H2 increase,while the release rates of CO and CO_(2) first increase and then decrease.The carbonization process of ICHB was segmented,and corresponding kinetic analysis was carried out.The results show that the activation energy of StageⅡand StageⅣis higher in the carbonization process of ICHB,and the active pyrolysis of coal and the reduction of iron ore occur in these two stages.In addition,the effect of heating rate on the kinetic parameters of ICHB carbonization process was investigated.It was found that when the heating rate increased,the reaction activation energy of StageⅣdecreased first and then increased,which was consistent with the release law of CO and CO_(2).The analysis showed that the increase in heating rate leads to more reactions at higher temperatures,resulting in an increase in the release rate of some gases.In addition,thermal hysteresis can also cause some processes to fail to fully react at the end of heating.It is also found that the apparent activation energy and preexponential factor have kinetic compensation effect during the car-bonization of ICHB.
文摘The rapid depletion of fossil fuel and growing demand necessitates researchers to find alternative fuels which are clean and sustainable. The need for finding renewable, low cost and environmentally friendly fuel resources can never be understated. An efficient method of generation and storage of hydrogen will enable automotive manufacturers to introduce hydrogen fuelled engine in the market. In this paper, a conventional DI diesel engine was modified to operate as gas engine. The intake manifold of the engine was supplied with hydrogen along with recirculated exhaust gas and air. The injection rates of hydrogen were maintained at three levels with 2 L/min, 4 L/min, 6 L/min and 8 L/min and 10 L/min with an injection pressure of 2 bar. Many of the combustion parameters like heat release rate (HRR), ignition delay, combustion duration, rate of pressure rise (ROPR), cumulative heat release rate (CHR), and cyclic pressure fluctuations were measured. The HRR peak pressure decreased with the increase in EGR rate, while combustion duration increased with the EGR rate. The cyclic pressure variation also increased with the increase in EGR rate.