Research On Supply Technology Of Blending Natural Gas Into Rural Biogas Network

In the cold winter,there are still larger technical problems to improve biogas production nowadays,and winter is the peak of energy consumption,centralized biogas supply can't meet the requirements of users who demand the stability gas.Marsh gas and conventional gas mixed supply is an effective way to complement the biogas when it is in short supply.Temperature is one of the key factors in biogas fermentation,this paper researches characteristics of gas production from a 20m3 biogas digesters made by glass steel,the capillary network as the front of the heat exchanger warming fermentation tank. Analysis and calculation thermal balance and heating technology economy of the mode.Result shows : capillary network increase temperature for biogas fermentation is feasible and more effective and economical.So as to guarantee the biogas' s continuous and steady supply,the paper has adopted the scheme of blending air into CNG gas to reinforce the 6T natural gas supply.And by calculating Wobbe index,combustion potential,the interchangeability judgement is assured,the research concludes that if air and CNG gas blended evenly as the ratio of 46:54~51:49,mixture could satisfy the interchangeability safety requirements.Throngh building up the inspirator mixer blending air into CNG combined with biogas as two gas sources supply devices.Analysis operating characteristics of the inspirator mixer,study the influence factors of inject ratios,the experiment concludes that: The inject ratios increase as the difference value between inject pressure and outlet pressure increase,which the outlet pressure of the inspirator mixer has greater influence on inject ratios.When the injection pressure, the outlet pressure is constant, the injection ratio and the volume of the injection air increased with the increasing of the valve opening of the air inlet.In order to satisfy the air CNG gas ratio by interchangeability calculation and guarantee enough incoming gas pressure,In the actual mixing progress,the outlet pressure value of the inspirator mixer should be stabilized at 6kpa,when the inlet pressure value of the inspirator mixer is controlled at 0.1~0.15 MPa,theCNG mixed air can replace 6T natural gas. Based on the theoretical analysis of gas exchange and safety, combined with the integrated system of automatic control.,a scheme of automatic control system of CNG mixed with air is put forwar.