Research On Catalytic Dehydrogenation Performance Of Au And Au-Ag Double Metals Supported On Al₂O₃ In Tail Chlorine At Low Temperature

Chlor-alkali industry is one of the most basic chemical industries.Chlor-alkali production has ranked first in the world in 2015 to reach more than30 million tons. Tail chlorine was mixture of multi-component gases by the concentration of liquefied electrolytic production of chlorine, containing chlorine, nitrogen, oxygen, hydrogen, and so on. Due to the explosive limit of hydrogen, tail chlorine cannot be used in downstream processes, affecting safety in the chlor-alkali industry.The experiment makes mixed gas in accordance with composition of industrial tail chlorine and achieves safely removal of hydrogen through catalytic dehydrogenation of hydrogen-oxygen reaction and hydrogen-chlorine reaction. We evaluate the performance of catalytic dehydrogenation by fixed bed reaction device. I draw primarily the three areas of study on the basis of the previous work :First, Au/Al₂O₃ catalyst and Au-Ag/Al₂O₃ bimetallic catalyst were prepared by method of anionic impregnation and incipient-wetnessimpregnation method. The experiment selected gamma-Al₂O₃ as carrier, gold chloride acid and silver nitrate as active metal source, prepared catalysts by impregnation of active component, soaking in dilute ammonia solution, washing with demonized water, and dry, calcinations, dehydrogenation.Second,the experiment use single factors variable method to research the influence of metal loadings, dilute ammonia soaking time, calcinations temperature, reduction temperature and reaction temperature on the effects of catalytic dehydrogenation. The experiments shows that: 0.7% metal loading,10 min immersion time,400℃ and 4 hours’ calcinations, 300℃ and 2 hours’ reduction, prepared Au/Al₂O₃ catalysts in the reaction temperature of 100℃, is excellent states for catalytic dehydrogenation, conversion of hydrogen is86.29%, selectivity of hydrogen-oxygen is 64.55%; 0.4%-0.7% metal loading,500 ℃ and 4 hours’ calcinations, 250 ℃ and 3 hours’ restore, prepared Au-Ag/Al₂O₃ bimetallic catalysts in the reaction of 100℃ is excellent states for catalytic dehydrogenation, hydrogen conversion is 94.58%, selectivity of hydrogen-oxygen is 59.28%.Third,by characterization of X-ray diffraction（XRD）, Fourier transform infrared spectroscopy（FTIR） and Nitrogen adsorption-desorption to know the micro-structure and surface properties of catalysts, as well as stability studies.The experiment shows: after loading and reaction,metal particles are highly spread and the basic framework of catalysts remains stable. Surface area and pore volume of activated alumina slightly decreases, loading and reaction doesnot change the pore structure of catalysts and stability.