Hydrogen Production Characteristics Of Portable NaBH₄ Hydrogen Generator And Its Regeneration Techno-economic Analysis

With the development of society and the continuous progress of science and technology,energy crisis and environmental pollution have gradually become the two major problems facing human development.Therefore,the development of clean energy is imperative.In the national"14th Five-Year"energy development plan,the growth of the clean energy industry is the primary goal and task for future development.As a type of energy with high energy density,hydrogen energy does not emit carbon dioxide and other greenhouse gases during the reaction process,and has the advantages of clean and pollution-free reaction products（water）.It is an ideal green energy carrier.In recent years,the construction of a"hydrogen energy society"has attracted widespread attention from domestic and foreign scholars.However,in order to realize the wide application of hydrogen energy,its storage and transportation is a severe problem that needs to be solved urgently.Hydrogen production from sodium borohydride（NaBH₄）hydrolysis is considered to be a promising portable hydrogen production technology due to its high purity hydrogen production,fast and controllable reaction,and green by-products.Through continuous research and exploration by domestic and foreign scholars in recent years,the technology of hydrogen production from NaBH₄ hydrolysis has made important research progress and has a certain degree of technological maturity.NaBH₄hydrogen generator prototypes and commercial products have also been facing the society and gradually put into human production and life.However,the current large-scale application of hydrogen production from NaBH₄hydrolysis technology is still limited by factors such as insufficient portability of hydrogen generators and high production cost of NaBH₄.In this paper,for the practical engineering application of fuel cell hydrogen source,the NaBH₄ hydrolysis reaction was studied.A cheap Co-P-B/nickel foam catalyst bed was prepared by a simple reduction-spraying method that can achieve large-scale mass production.Its catalytic performance of NaBH₄ hydrolysis to produce hydrogen was studied,and the optimal reaction operating parameters were obtained.On this basis,a prototype hydrogen generator was constructed,and its operational stability,dynamic response characteristics and restart characteristics were studied.The practicality is verified by coupling the hydrogen generator and the proton exchange membrane fuel cell.In addition,in view of the high cost of synthesizing NaBH₄ in the industry,a closed-loop system scheme was proposed to regenerate NaBH₄from the hydrolysis by-product NaBO₂.By analyzing the material flow and energy flow of the model,the cost and energy consumption of the NaBH₄ thermal regeneration process are evaluated.The sensitivity analysis of the key parameters that affect the cost of NaBH₄thermal regeneration is carried out.The main research results of this paper are as follows:（1）A high-efficiency Co-P-B/nickel foam catalyst bed for NaBH₄ hydrolysis was prepared by reduction-spraying method.When the fuel feed rate is 3 mL/min,the Co-P-B loading capacity is 6 mg/cm²,and the catalyst bed length is 10 cm,the hydrogen production rate of NaBH₄ hydrolysis reaches 1.5 L/min,which can fully meet the hydrogen supply demand of a typical 100 W hydrogen fuel cell stack.The conversion rate of NaBH₄ during the reaction is as high as 96%.（2）The designed and manufactured NaBH₄ hydrogen generator runs stably and reliably,has fast dynamic response characteristics and excellent restart performance.It can realize stable hydrogen supply for 7 hours continuously at a rated hydrogen production rate of 1.5 L/min.In addition,the hydrogen production rate can also be dynamically adjusted according to task requirements.The NaBH₄ hydrogen generator has a total hydrogen supply of 670 L at room temperature and pressure,which can be used as a portable hydrogen source for practical applications.（3）The techno-economic analysis of the process of recovering the by-product of the hydrolysis reaction NaBO₂ to regenerate NaBH₄ shows that the production cost per ton of NaBH₄ is 28,500 RMB,which is 5.5 times lower than the current Schlesinger synthesis method widely used in industry.The cost of portable hydrogen production has dropped to 135 RMB/kg,which fully demonstrates the economic feasibility of large-scale application of hydrogen production by NaBH₄ hydrolysis.