Design Of Photothermal Generator Based On Meltblown Ultrafine Fiber And Research On Interface Evaporation Performance

The energy crisis and the shortage of fresh water have become two major global problems.Using solar desalination technology to produce fresh water is one of the most promising ways to solve the energy crisis and fresh water shortage.However,there are a series of problems for high-efficiency solar evaporation systems,such as low photothermal conversion efficiency,serious heat loss,high cost,complex design,etc.These series of problems seriously hinder its large-scale promotion.In view of the above difficulties,this research topic uses meltblown fibers to design a new and efficient solar interface steam generator,and systematically studies a series of problems affecting the evaporation performance of these two solar steam generators.The research results provide new ideas for the design and optimization of solar interfacial evaporation systems,and demonstrate the great potential of meltblown fiber materials for photothermal evaporation applications.The main research contents and conclusions of the paper are as follows:（1）In this paper,a flexible non-woven fabric with rough surface,porous and fluffy surface was prepared by melt blowing process and spraying method.The fiber surface is wrapped with polyethylene terephthalate（PET）/polypropylene（PP）composite non-woven fabric as base material,and polydopamine（PDA）as adhesive and hydrophilic agent.Multi-walled carbon nanotubes（WCNTS）are used as light-absorbing materials to bond with the fiber surface to form an efficient solar evaporator.The rough fabric surface makes the incident light diffusely reflected in the absorption layer for many times,thereby increasing the light absorption rate（≈94%）,while the fluffy and porous micron-scale network structure of the composite non-woven fabric exhibits a strong capillary effect.Based on these advantages,a two-dimensional waterway is designed,and the air suspension evaporation method is used for evaporation.Under one solar irradiation(1kw·m^-2),the water evaporation rate reaches 1.42 kg·m^-2h^-1,and the conversion efficiency is close to 92%.Most importantly,this composite material is easy to produce and can be scaled industrially,promising to solve the problem of clean water scarcity.（2）First,we prepared PPS pulp with meltblown polyphenylene sulfide（PPS）as raw material.The PPS pulp and two carbon fibers（CF）of different sizes were subjected to super-wetting modification,then deposited by two suction filtrations,and then heat-treated to obtain a"reinforced concrete"-like structure with unique waterways.Finally,after loading PVDF/WCNTS hydrophobic photothermal material,a self-floating and efficient solar evaporator is obtained.After a series of photothermal evaporation performance investigations,it is concluded that the prepared steam generator has efficient water transport,extensive and strong light absorption（≈92%）,and the unique waterway design can greatly suppress hot water guide.Finally,under 1sunlight intensity(1kw·m^-2),the maximum evaporation rate reached 1.24 kg·m^-2h^-1,and the maximum conversion efficiency reached 79.2%.