以费-托合成馏分油为原料,采用梯度冷却尿素络合法对正构烷烃进行分离,生产煤基费-托合成液体石蜡,考察了降温速率和络合反应条件对正构烷烃分离效果的影响,并采用气相色谱-质谱联用仪、详细烃组成分析等方法对产物的组成进行分析,结果...以费-托合成馏分油为原料,采用梯度冷却尿素络合法对正构烷烃进行分离,生产煤基费-托合成液体石蜡,考察了降温速率和络合反应条件对正构烷烃分离效果的影响,并采用气相色谱-质谱联用仪、详细烃组成分析等方法对产物的组成进行分析,结果表明:当反应体系的温度由45℃以1℃min的速率下降至25℃,尿素异丙醇水溶液与油的质量比为10∶1,尿素、异丙醇、水的质量比为38∶40∶22时,经馏分切割得到的重质液体石蜡中正构烷烃质量分数为93%左右,其各项性质满足NB SH T 0416—2014质量标准要求;与传统冷却尿素络合法相比,梯度冷却尿素络合法的液体石蜡产品纯度和正构烷烃回收率均大幅提高。展开更多
Temperature gradient and cooling rate have an obvious effect on formation of methane hydrate. The process for formation of methane hydrate in coarse sand is monitored to tmderstand the relationship between temperature...Temperature gradient and cooling rate have an obvious effect on formation of methane hydrate. The process for formation of methane hydrate in coarse sand is monitored to tmderstand the relationship between temperature gradient and cooling rate and nucleation, growth and distribution of methane hydrate by using the electrical resistivity method. The results show that the change of resistivity can better reflect the nucleation and growth and distribution of methane hydrate. Temperature gradient promotes the nucleation, formation, and formation rate of methane hydrate. At a temperature gradient of 0.11℃/cm, the rate of methane hydrate formation and saturation reaches a maximum. Cooling rate has little effect on the methane hydrate formation process. Judging from the outcome of final spatial distribution of methane hydrate, the cooling rate has an obvious but irregular effect in coarse sand. The effect of tempera^re gradient on distribution of methane hydrate in coarse sand is less than that of cooling rate. At a temperature gradient of 0.07℃/cm, methane hydrate is distributed uniformly in the sample. If the temperature gradient is higher or lower than this value, the hydrate is enriched in the upper layer of sample.展开更多
The work aims to develop a process for freezing desalination of seawater on cold walls. The experiments were performed with water/NaCl solutions of different concentrations and with samples of seawater. The pilot crys...The work aims to develop a process for freezing desalination of seawater on cold walls. The experiments were performed with water/NaCl solutions of different concentrations and with samples of seawater. The pilot crystallizer consists of a cooled tube immersed in a cylindrical double jacketed tank containing water to be treated. The complete process of desalination is conducted in two steps： the freezing step, leading to the crystallization of the ice layer and the sweating step, which consists of purifying the ice layer in depth by melting the impure zones. The systematic study of the influence of operating parameters has highlighted the important role of the cooling ramp and salinity of the solution on the purity of the ice produced. In the absence of stirring, the temperature of the double jacket also has a noticeable effect on the purity of the ice due to temperature gradients, and consequently, convection currents that may result in the solution. The results of this work show the feasibility of the technique and give a good indication of operating conditions that can be used to produce drinking water.展开更多
文摘以费-托合成馏分油为原料,采用梯度冷却尿素络合法对正构烷烃进行分离,生产煤基费-托合成液体石蜡,考察了降温速率和络合反应条件对正构烷烃分离效果的影响,并采用气相色谱-质谱联用仪、详细烃组成分析等方法对产物的组成进行分析,结果表明:当反应体系的温度由45℃以1℃min的速率下降至25℃,尿素异丙醇水溶液与油的质量比为10∶1,尿素、异丙醇、水的质量比为38∶40∶22时,经馏分切割得到的重质液体石蜡中正构烷烃质量分数为93%左右,其各项性质满足NB SH T 0416—2014质量标准要求;与传统冷却尿素络合法相比,梯度冷却尿素络合法的液体石蜡产品纯度和正构烷烃回收率均大幅提高。
基金supported by the Chinese Academy of Sciences Action-plan for Western Project(No.KZCX2-XB3-03)the National Natural Science Foundation of China(No.41001038,51266005)the National Natural Science Foundation of China(No.41101070,1106ZBB007)
文摘Temperature gradient and cooling rate have an obvious effect on formation of methane hydrate. The process for formation of methane hydrate in coarse sand is monitored to tmderstand the relationship between temperature gradient and cooling rate and nucleation, growth and distribution of methane hydrate by using the electrical resistivity method. The results show that the change of resistivity can better reflect the nucleation and growth and distribution of methane hydrate. Temperature gradient promotes the nucleation, formation, and formation rate of methane hydrate. At a temperature gradient of 0.11℃/cm, the rate of methane hydrate formation and saturation reaches a maximum. Cooling rate has little effect on the methane hydrate formation process. Judging from the outcome of final spatial distribution of methane hydrate, the cooling rate has an obvious but irregular effect in coarse sand. The effect of tempera^re gradient on distribution of methane hydrate in coarse sand is less than that of cooling rate. At a temperature gradient of 0.07℃/cm, methane hydrate is distributed uniformly in the sample. If the temperature gradient is higher or lower than this value, the hydrate is enriched in the upper layer of sample.
文摘The work aims to develop a process for freezing desalination of seawater on cold walls. The experiments were performed with water/NaCl solutions of different concentrations and with samples of seawater. The pilot crystallizer consists of a cooled tube immersed in a cylindrical double jacketed tank containing water to be treated. The complete process of desalination is conducted in two steps： the freezing step, leading to the crystallization of the ice layer and the sweating step, which consists of purifying the ice layer in depth by melting the impure zones. The systematic study of the influence of operating parameters has highlighted the important role of the cooling ramp and salinity of the solution on the purity of the ice produced. In the absence of stirring, the temperature of the double jacket also has a noticeable effect on the purity of the ice due to temperature gradients, and consequently, convection currents that may result in the solution. The results of this work show the feasibility of the technique and give a good indication of operating conditions that can be used to produce drinking water.
