The Study Of Low Concentration Oxygen-containing Coalbed Methane On Deoxidization-separation And Enrichment Of Methane

The coalbed methane is rich in the Guizhou province.However,because of the complex topography,the extraction of coalbed methane is mostly low and its utilization rate is just 5-7%when the methane concentration less than 30%.Aim at the low concentration oxygen-containing coalbed methane,most is direct emptiedultimately.This is not only waste energy but also cause serious environmental pollution.So the reasonable development and utilization of low concentration oxygen-containing coalbed methane have significant influence on developing the economical benefits and environmental protection benefits.Based on the characteristics of coalbed methane in Guizhou province,the simulation mixture gas was prepared which contained methane(20%),nitrogen(64%),and oxygen(16%).The paper major study the technology of deoxygenation and then enriching the meanthe.The specific studies were as follows:In this paper,oxygen removal ability of deoxidier that were prepared by the active component(Na₂S),thecarrier(activated carbons)and promoter(transition metal ion)applied to low concentration oxygen-containing coalbed methane was investigated.Results showed the better deoxidier is prepared by Na₂S,AC-1 and 2%of Co(?)that was treated stepping impregnation method.And Under the condition of270?,the effective deoxidization time reach 641.74min,the effective amount of deoxidation per unit was 62.66m L/g and the Na₂S conversion was 90.03%if the rate of deoxidation was 99.9%.The influence on methane enrichment accomplished by means of modified methods by pore structure and surface chemical property was studied.The modified activated carbons was prepared by treated the activated carbons with KOH,N₂and the combination KOH with N₂,respectively.Results show that modified ways can all improve the micropore volumes,and the micropore volumes of the third modified method is maximum,is 0.922m³/g,the total base number is 1.5661,the adsorption capacity of CH₄is 27.42m L/g,the concentration of CH₄also increased from 23.8%to35.24%in gas mixture of CH₄/N₂.The modified activated carbons was prepared by treated the activated carbons with Br₂deposition and Mo O₂impregnation,respectively.The modified methaods improve the separation factor,reach 4.55and 4.89,the concentration of CH₄also increased from 23.8%to 37.29%and 36.94%in gas mixture of CH₄/N₂,respectively.Based on the above research foundation,the influence of adsorption and desorption conditions of VPSA and the combination modificationof methane enrichment was investigated.Results show when theloading degree of AC is 0.4g,the flow of coalbed methane without oxygen is 5m L/min,the adsorption temperature is15?and the desorption time is 110s,modified by combination KOH-N₂with Br₂and combination KOH-N₂with Mo O₂improve the separation factor,reach4.68 and 5.02,the concentration of CH₄also increased from 23.8%to 42.06%and 41.16%in gas mixture of CH₄/N₂,respectively.