Method suitable for storage and transportation of hydrate above zero DEG C
阅读说明：本技术 一种适用于零摄氏度以上水合物储运的方法 (Method suitable for storage and transportation of hydrate above zero DEG C ) 是由 陈俊 曾耀松 陈光进 雷艳华 蒋建宏 邓斌 李家元 于 2020-05-12 设计创作，主要内容包括：本发明公开了一种适用于零度以上水合物储运的方法,包括以下步骤：在水合物形成体系中加入能强化零摄氏度以上自保护效应的分子,待水合物形成后,调控压力进行储运；其中,所述能强化零摄氏度以上自保护效应的分子的添加比例为30％以上。本发明方案通过从主体分子入手,巧妙地将自保护效应提升至零度以上；水合物形成过程与传统水合物形成过程相同,然而,在水合物分解过程中由于主体分子掺杂或改变,使得水合物分解过程被抑制；主体水相的变化能够强化水合物本身的自保护效应,进而抑制水合物的分解过程,本发明方案的主体水相可以包括重水及其它可能形成水合物或类似水合物的物质,当温度高于273.2K也能产生自保护效应,减少水合物法储气过程中需要的冷能。(The invention discloses a method suitable for storage and transportation of hydrates above zero, which comprises the following steps: adding molecules capable of strengthening self-protection effect above zero centigrade degree into the hydrate forming system, and regulating and controlling pressure for storage and transportation after the hydrate is formed; wherein the addition proportion of the molecules capable of strengthening the self-protection effect above zero centigrade is above 30%. The scheme of the invention skillfully promotes the self-protection effect to be above zero by starting from the main molecule; the hydrate formation process is the same as the conventional hydrate formation process, however, the hydrate decomposition process is inhibited due to doping or changing of the host molecule in the hydrate decomposition process; the change of the main water phase can strengthen the self-protection effect of the hydrate and further inhibit the decomposition process of the hydrate, the main water phase of the scheme of the invention can comprise heavy water and other substances which can form the hydrate or similar hydrates, and the self-protection effect can be generated when the temperature is higher than 273.2K, thereby reducing the cold energy required in the gas storage process of the hydrate method.)
1. A method suitable for storage and transportation of hydrate above zero degree is characterized in that: the method comprises the following steps:
adding molecules capable of strengthening self-protection effect above zero centigrade degree into the hydrate forming system, and regulating and controlling pressure for storage and transportation after the hydrate is formed;
wherein the addition proportion of the molecules capable of strengthening the self-protection effect above zero centigrade is more than 30% of the mass of the hydrate main body; preferably 30 to 90 percent; more preferably 30 to 60%.
2. The method for storing and transporting hydrate above zero according to claim 1, wherein the method comprises the following steps: the molecules capable of enhancing the self-protection effect above zero degrees centigrade include molecules which replace the main water molecules to form hydrates.
3. The method for storing and transporting hydrate above zero according to claim 2, wherein the method comprises the following steps: the molecules that form hydrates in place of the bulk water molecules include heavy water.
4. The method for storing and transporting hydrate above zero according to claim 1, wherein the method comprises the following steps: the molecules capable of enhancing the self-protecting effect above zero degrees centigrade include substances capable of forming hydrogen bonds.
5. The method for storing and transporting hydrate above zero according to claim 1, wherein the method comprises the following steps: the method further comprises adding a kinetic enhancer to the hydrate-forming system.
6. The method for storing and transporting hydrate above zero according to claim 1, wherein the method comprises the following steps: the hydrate-forming system includes a gas phase system containing at least one of methane, ethane, carbon dioxide, and hydrogen.
7. The method for storing and transporting hydrate above zero according to claim 6, wherein the method comprises the following steps: the gas phase system contains natural gas.
8. The method for storing and transporting hydrate above zero according to any one of claims 1 to 7, characterized in that: the pressure in the storage and transportation process is below 3 Mpa; more preferably 0.5MPa or less.
9. The method for storing and transporting hydrate above zero according to any one of claims 1 to 7, characterized in that: the temperature above zero DEG C is 0.1-20 ℃.
10. The method for storing and transporting hydrate above zero according to claim 1, wherein the method comprises the following steps: the temperature above zero DEG C is 0.5-15 ℃; more preferably 0.5 to 10 ℃; more preferably 0.5 to 3.5 ℃.
Technical Field
The invention relates to the field of hydrate method gas storage and related technologies, in particular to a method suitable for storage and transportation of hydrates above zero degrees centigrade.
Background
The gas hydrate is a non-stoichiometric ice-like cage-shaped compound generated by small molecule gas and water at low temperature and high pressure. According to the characteristic that the gas hydrate wraps the small molecule gas, the gas can be stored and transported in a hydrate forming mode. Taking methane hydrate as an example, 1 volume of methane hydrate can store more than 150 volumes of methane gas. The natural gas can stably exist at the temperature of 263.2K to 282.2K and the pressure of 6.5MPa, and the storage pressure is far lower than that of compressed natural gas (20MPa to 30 MPa). However, in order to reduce the pressure of methane storage in the hydrate method, it is generally adopted to reduce the hydrate-forming pressure by reducing the phase equilibrium conditions of the hydrate formation by adding a thermodynamic promoter such as tetrahydrofuran, cyclopentane, quaternary ammonium salt, etc. The addition of a thermodynamic promoter significantly reduces the pressure at which hydrates are formed, but thermodynamic promoters themselves also typically form hydrates or semi-clathrate hydrates, which reduces gas storage capacity of the hydrate process. In addition, when the temperature is lower than zero degrees centigrade, the self-protection effect generated when the hydrate below zero degree centigrade is decomposed can be used to reduce the gas storage pressure. The self-protective effect process is a naturally occurring effect, i.e. sub-zero hydrates are significantly reduced in decomposition rate compared to theory. This particular phenomenon was considered to be discovered in 1986, and was defined as a self-protective effect in 1992. The gas storage and transportation by the hydrate method can be realized below zero by the self-protection effect, and the storage and transportation pressure can be below 3.5MPa, even as low as the normal pressure. The Chinese patent application document CN104061435A discloses a hydrate storage and transportation method based on self-protection effect, and particularly discloses that natural gas is stirred in a hydrate reactor under the conditions of low temperature and high pressure to generate a slurry hydrate; dehydrating the generated slurry hydrate, processing the slurry hydrate into a hydrate snowball, and freezing the hydrate snowball; then, filling the frozen hydrate snowball into a low-temperature storage cabin, and keeping the temperature in the cabin at 253-273K; and (3) filling gas into the cabin to maintain the pressure in the cabin at 0.1-0.2 Mpa and keep the cabin in a sealed state. By maintaining the temperature at 253-273K, the decomposition of the hydrate is slowed down, and the low-pressure transportation time is prolonged. The self-protection effect is further strengthened, and the gas storage and transportation are realized by utilizing the self-protection effect of the hydrate.
However, there is no report on how to increase the self-protection effect above zero degrees centigrade. Since the self-protection effect was discovered in 1986, it has been considered that the self-protection effect exists only below zero degree, and the process of strengthening the self-protection effect is all using auxiliary means, for example, the patent CN104061435A teaches that the hydrate is made into a spherical shape in the range of 253-273K. Therefore, if the self-protection effect can be improved to be more than zero degree, the method has milestone significance for gas storage by a hydrate method.
Disclosure of Invention
The present invention is directed to solving at least one of the problems of the prior art. Therefore, the invention provides a method for storing and transporting the hydrate, which can improve the self-protection effect of the hydrate decomposition to be more than zero degree.
The hydrate storage and transportation method comprises the following steps:
adding molecules capable of strengthening self-protection effect above zero centigrade degree into the hydrate forming system, and regulating and controlling pressure for storage and transportation after the hydrate is formed;
wherein the addition proportion of the molecules capable of strengthening the self-protection effect above zero centigrade is more than 30% of the mass of the hydrate main body; preferably 30 to 90 percent; more preferably 30 to 60%.
According to some embodiments of the invention, the molecules capable of enhancing self-protective effects above zero degrees centigrade comprise molecules that form hydrates in place of the bulk water molecules; preferably, the molecules that form hydrates in place of the bulk water molecules include heavy water.
According to some embodiments of the invention, the method further comprises adding a kinetic accelerator to the hydrate-forming system.
According to some embodiments of the invention, the hydrate formation system comprises a gas phase system comprising at least one of methane, ethane, carbon dioxide, hydrogen; preferably, the gas phase system comprises natural gas.
According to some embodiments of the invention, the hydrate-forming system comprises a liquid phase system including a pure water system, a brine system, an emulsion system, or a solution system containing a kinetic enhancer.
According to some embodiments of the invention, the pressure during storage and transportation is below 3 Mpa; more preferably 0.5MPa or less.
According to some embodiments of the invention, the above zero degrees centigrade means 0.1 to 20 ℃; preferably 0.5-15 ℃; more preferably 0.5 to 10 ℃; more preferably 0.5 to 3.5 ℃.
The preparation method according to the embodiment of the invention has at least the following beneficial effects: the scheme of the invention skillfully promotes the self-protection effect to be above zero by starting from the main molecule; the hydrate formation process is the same as the conventional hydrate formation process, however, the hydrate decomposition process is inhibited due to doping or changing of the host molecule in the hydrate decomposition process; the self-protection effect of the hydrate can be enhanced by utilizing the change of the main water phase, so that the decomposition process of the hydrate is inhibited, the main water phase of the scheme of the invention can comprise heavy water and other substances which can form the hydrate or similar hydrates, and the self-protection effect can be generated when the temperature is higher than 273.2K, so that the cold energy required in the gas storage process of the hydrate method is reduced; according to the embodiment of the invention, after the gas and the liquid of other main body molecules are mixed in the main body water phase to form the hydrate, the hydrate is placed in a storage and transportation container, the pressure in the container is regulated and controlled, the container is kept closed, and the self-protection effect can be generated in the decomposition process of the hydrate above zero, so that the safe storage and transportation of the gas are realized, and the decomposition rate of the hydrate can be reduced by about 5-12 times within half an hour.
Additional aspects and advantages of the invention will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of the invention.
Drawings
FIG. 1 is a schematic view of the structure of all the apparatuses in the reaction process of example 1 of the present invention;
FIG. 2 is a graph of decomposition rate of methane hydrate with different heavy water content at 273.7K versus time in example 1 of the present invention;
FIG. 3 is a plot of the rate of hydrate decomposition over time at different temperatures in the heavy water to methane hydrate formation of example 2 of the present invention.
Description of reference numerals:
1. a first valve body; 2. a vacuum pump; 3. a second valve body; 4. a third valve body; 5. a fourth valve body; 6. a first autoclave; 7. a second autoclave; 8. a glycol water bath; 9. a fifth valve body; 10. a sixth valve body; 11. a first pressure sensor; 12. a second pressure sensor; 13. a first temperature sensor; 14. a second temperature sensor; 15. a sixth valve body; 16. a computer; 17. a gas cylinder.
Detailed Description
In order to explain technical contents, achieved objects, and effects of the present invention in detail, the following description is made with reference to the accompanying drawings in combination with the embodiments. The test methods used in the examples are all conventional methods unless otherwise specified; the materials, reagents and the like used are commercially available reagents and materials unless otherwise specified.
The first embodiment of the invention is as follows: a method for storing and transporting hydrate includes adding heavy water to hydrate forming system (methane-water), exhausting pressure to storage and transportation pressure, and sealing the container. The structural schematic diagram of the container is shown in fig. 1, and specifically comprises a
Methane forms hydrates at 273.7K in a heavy water-water mixed system containing 0 wt%, 30 wt%, 50 wt% and 90 wt%. After the hydrate is completely formed, the pressure can be directly vented to normal pressure and then decomposed for 12 hours. After decomposing for 12 hours, the temperature is raised to 293.2K to completely decompose the hydrate. The percentage of hydrate decomposition at different times was calculated from the pressure data to give a time-decomposition rate graph, the results of which are shown in fig. 2. As can be seen from fig. 2, the hydrate decomposed without the addition of heavy water to a final percentage of 92.2% over 1 hour. Also 82.2% was reached already at 0.5 h, indicating that at 273.7K, there was no self-protective effect of methane hydrate decomposition. When 30 wt%, 50 wt% and 90 wt% of heavy water was added, the decomposition percentage of the hydrate at 0.5 hour was reduced to 15.0%, 7.4% and 7.0%, respectively. The final percentage decomposition over 12 hours also dropped to 55.2%, 29.6% and 17.7%, respectively. It is shown that when 30 wt%, 50 wt% and 90 wt% of heavy water is added at 273.7K, there is a self-protecting effect and the rate of decomposition of the hydrate decreases significantly when the hydrate content is increased from 30% to 50%, and more gradually when the hydrate content is increased from 50% to 90%.
The second embodiment of the invention is as follows: a method for storing and transporting gas by hydrate method, hydrate is generated by reaction equipment as shown in figure 1, methane forms hydrate in pure heavy water system, pressure is discharged to normal pressure after hydrate is formed, and decomposition is carried out for 12 hours under 273.7K, 274.7K and 276.2K respectively, and the curve chart of the relation between decomposition percentage and time is shown in figure 3. As is clear from fig. 3, the final decomposition percentage of methane hydrate at 273.7K after 12 hours was 15.7. 274.7K and 276.2K showed methane hydrate decomposition percentages of 25.8% and 65.9%, respectively, after 12 hours. The self-protection effect exists in the methane hydrate decomposition process at the temperature. Namely, the self-protection effect in the hydrate decomposition process is improved to be above zero, and the gas storage and transportation can be carried out by the method.
The above description is only an embodiment of the present invention, and not intended to limit the scope of the present invention, and all equivalent changes made by using the contents of the present specification and the drawings, or applied directly or indirectly to the related technical fields, are included in the scope of the present invention.
- 上一篇：一种医用注射器针头装配设备
- 下一篇：一种U型连体压力容器