In this paper, the saturated solution crystallization method is proposed to promote the formation of hydrate by means of the known similarities between the hydrate formation process and the crystallization process. In...In this paper, the saturated solution crystallization method is proposed to promote the formation of hydrate by means of the known similarities between the hydrate formation process and the crystallization process. In this method,adding the second phase crystals was used to replace the spontaneous formation of hydrate crystal nuclei to form hydrate.The effects of saturated Na_2SO_4, MgSO_4, NH_4HCO_3 and CuSO_4 solutions on the formation rates of natural gas hydrate and gas storage capacity were investigated. The results showed that the saturated solution had an influence on the hydrate formation process. Under the given experimental conditions, the saturated Na_2SO_4 solution showed a highest increase in the hydrate formation rate, and the average hydrate formation rate in its presence was 11.8 times higher than that obtained in the deionized water. Moreover, the largest formation rate of gas hydrates observed in the saturated Na_2SO_4 solution was 386 times bigger than that in the deionized water, and the gas storage capacity increased by 10 times. In addition, the average hydrate formation rate in the saturated Mg SO_4 solution was faster than that in water by 20 times. The largest formation rate of gas hydrates in the saturated MgSO_4 solution was 165 times faster than that obtained in the deionized water, and the gas storage capacity increased by 6.2 times. The saturated NH_4HCO_3 and saturated CuSO_4 solutions also influenced the formation process of hydrate. Therefore, the crystallization method of saturated solution can be used to achieve a highefficiency preparation of natural gas hydrates, which provides theoretical guidance for the storage of natural gas in the form of hydrate.展开更多
水热体系下合成了新型层状UZM-8沸石,采用~13C交叉极化魔角旋转核磁共振(~13C CP MAS NMR)谱研究了该体系下二甲基二乙基氢氧化铵(DEDMAOH)的模板导向作用。研究结果表明,DEDMA^+与沸石发生较强的相互作用,处于沸石的不同化学环境中,起...水热体系下合成了新型层状UZM-8沸石,采用~13C交叉极化魔角旋转核磁共振(~13C CP MAS NMR)谱研究了该体系下二甲基二乙基氢氧化铵(DEDMAOH)的模板导向作用。研究结果表明,DEDMA^+与沸石发生较强的相互作用,处于沸石的不同化学环境中,起到了较强的模板导向作用。采用XRD和SEM方法对合成的UZM-8沸石进行了表征,考察了晶种和Na^+对UZM-8沸石的形成及结构的影响。实验结果表明,当n(DEDMA^+)∶n(SiO_2)<0.3时,合成体系中UZM-8沸石无法自发结晶,而当体系中存在Na^+和晶种时,n(DEDMA^+)∶n(SiO_2)=0.1时仍可合成出UZM-8沸石,且合成产物UZM-8沸石的结晶度提高,晶化时间缩短。展开更多
基金the Program for Liaoning Excellent Talents in University (LJQ2014038)the Natural Science Foundation of Liaoning Province (201602470)
文摘In this paper, the saturated solution crystallization method is proposed to promote the formation of hydrate by means of the known similarities between the hydrate formation process and the crystallization process. In this method,adding the second phase crystals was used to replace the spontaneous formation of hydrate crystal nuclei to form hydrate.The effects of saturated Na_2SO_4, MgSO_4, NH_4HCO_3 and CuSO_4 solutions on the formation rates of natural gas hydrate and gas storage capacity were investigated. The results showed that the saturated solution had an influence on the hydrate formation process. Under the given experimental conditions, the saturated Na_2SO_4 solution showed a highest increase in the hydrate formation rate, and the average hydrate formation rate in its presence was 11.8 times higher than that obtained in the deionized water. Moreover, the largest formation rate of gas hydrates observed in the saturated Na_2SO_4 solution was 386 times bigger than that in the deionized water, and the gas storage capacity increased by 10 times. In addition, the average hydrate formation rate in the saturated Mg SO_4 solution was faster than that in water by 20 times. The largest formation rate of gas hydrates in the saturated MgSO_4 solution was 165 times faster than that obtained in the deionized water, and the gas storage capacity increased by 6.2 times. The saturated NH_4HCO_3 and saturated CuSO_4 solutions also influenced the formation process of hydrate. Therefore, the crystallization method of saturated solution can be used to achieve a highefficiency preparation of natural gas hydrates, which provides theoretical guidance for the storage of natural gas in the form of hydrate.
文摘水热体系下合成了新型层状UZM-8沸石,采用~13C交叉极化魔角旋转核磁共振(~13C CP MAS NMR)谱研究了该体系下二甲基二乙基氢氧化铵(DEDMAOH)的模板导向作用。研究结果表明,DEDMA^+与沸石发生较强的相互作用,处于沸石的不同化学环境中,起到了较强的模板导向作用。采用XRD和SEM方法对合成的UZM-8沸石进行了表征,考察了晶种和Na^+对UZM-8沸石的形成及结构的影响。实验结果表明,当n(DEDMA^+)∶n(SiO_2)<0.3时,合成体系中UZM-8沸石无法自发结晶,而当体系中存在Na^+和晶种时,n(DEDMA^+)∶n(SiO_2)=0.1时仍可合成出UZM-8沸石,且合成产物UZM-8沸石的结晶度提高,晶化时间缩短。
