| Summary: | 碩士 === 國立臺灣大學 === 化學工程學研究所 === 100 === This study demonstrated the equilibrium conditions for the formation of methane hydrates in the presence of cyclic ethers and alkyl amine, i.e. 2,3-dihydrofuran, 2-ethyloxirane, N-ethylethanamine and N,N-dimethylethanamine. Also we selected the compound which has these two functional group: 1-(2-furyl)methylamine. The three-phase (H-Lw-V) and the four-phase (H-Lw-La-V) equilibrium data in methane +
water + additives systems were measured by using isochoric method in the range of pressures from 8 to 13 MPa and temperature up to 301K. When 10wt% 2,3-dihydrofuran, N-ethylethanamine, N,N-dimethylethanamine and 1-(2-furyl)methylamine were added into methane hydrates systems respectively, the hydrate equilibrium temperatures showed a little decrease approximately 1.2 K for 2,3-dihydrofuran, 1.3~1.5 K for N,N-dimethylethanamine, 2.3 K for N-ethylethanamine and 2.2K for 30wt% 1-(2-furyl)methylamine at a specific pressure. On the other hand, adding 5wt% 2-ethyloxirane can increase the hydrate equilibrium temperatures by 2.2~2.6K. Moreover, in order to simulate the sea-water environment, the methane + 3.5wt% NaCl+ 30wt% 1-(2-furyl)methylamine systems were measured to acquire the equilibrium data of methane hydrate dissociation. With the existence of 3.5 wt% NaClin this system, the equilibrium temperature of the brine system reduced 2K compared to the original system. While measureing the equilibrium point of 1-(2-furyl)methylamine, we found that it has a kinetic inhibition effect, i.e. it can extend the time for hydrate formation. The experiment showed that the best effect is adding 30wt% 1-(2-furyl)methylamine which can increase the induction time from about 3hrs to 13hrs. But it didn’t affect the formation rate and the total consumed moles of methane. In the structure prediction by Clausius-Clapeyron Equation, we found that when adding 2,3-dihydrofuran and 1-(2-furyl)methylamine, the hydrates will form structure I, and form structure II while adding 2-ethyloxirane.
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