Study On Tetrahydrofuran Hydrate Growth Outside Threaded Tube

As one of the main means of peaking and filling the valley of the power system,the cold storage technology has significant economic and social significance,which not only can reduce the peak and valley pressure of the power grid,but also bring greater economic value.Hydrate cold storage technology is an important development direction of cold storage technology,with good application and development prospects.In order to solve the problem of slow formation of hydrate,the experimental and simulant results of threaded tube enhanced hydrate formation of tetrahydrofuran?THF?were investigated in this thesis.The dimensions of threaded tube were optimized based the prementioned results.At the end of the thesis,several cases of the cold storage ability of hydrate were analyzed and compared to offer useful reference to the engineering of hydrate cold storage.In the thesis,the hydrate formation experiments were conducted in a single thread tube at room pressure?101.325kPa?with THF,and 50%ethanol was used for cool media.The experimental result indicated that the reduction of hydrate formation time and increase of mass ratio of THF outside the threaded tube were enhanced by increasing the flow rate of cooling media and degree undercooling.The primitive optimized degree of undercooling is 13.4K,and flow rate of cooling media is 0.25m/s.The respective THF formation time,mass ratio and rate are 179.12min,0.48 and 2.67×10^-3 min^-1.At the same time,the mass ration and rate of hydrate formation at the outside of threaded tube is 1.16 and 1.26 times than the bare tube.COMSOL was used here to compare the numerical result and experimental result,and deviation between them is under 5%,which approved the accuracy and applicability of the COMSOL model.The optimization of threaded tube was based on the simulated result as well.Based on the result of simulation and experiments,the width of threaded tube is the key factor to affect the formation of hydrate.For example,wide threaded context leads to higher mass ratio of THF hydrate formation.In a reasonable range,the THF formation time,and increasing mass ratio can be reduced by increasing the thickness and space of threaded texture.However,further increase of thickness and space of thread texture resulted inversed effect on the formation of hydrate.Since the using of high thermal conductive material as threaded tube can increase the formation of THF hydrate,aluminum tube with the high thermal conductivity,low density and good erosive resistance is the optimal candidate for making threaded tube.Finally,a economic calculation is proposed for the cold storage air conditioning project case,With the same operating costs,the optimized tube and THF hydrate storage cold solution proposed in this paper saves equipment and investment of 2,154,400 yuan compared with the ice storage and cooling scheme,reducing the investment cost of 15.66%.