Experiment Study Of Biogas Upgrading To Vehicle Fuel

This study supported by national agricultural science and technology across project The Integration and Demonstration of Cycle Agricultural Technology with Straw Energy Utilization as Core Technology and national science and technology support programme special project The Comprehensive Demonstration Project of Anaerobic Fermentation Produce Biogas Project in Farm in Livestock and Poultry Dense Areas in Middle China. As a part of the two projects, the study researched and designed suitable biogas upgrading method suitable for our country and Henau province, produced high-quality biogas could be used as vehicle fuel.Two steps biogas upgrading technology was adopted in the paper, pressured water washing was the main technology and dry absorb was the assisted technlolgy, and a set of biogas upgrading experiment equipment with handling capacity of 2.4m3·h^-1 was designed and fixed, and then a series of experiments of biogas water scrubbing with nomal pressure, biogas compressed water scrubbing, biogas compressed water scrubbing with adsorbabe column packings, and two steps of water washing combined sodium-based dry regenerable sorbent absorb were done through the equipment. Operation methods of biogas upgrading were adjusting, experiment effects were increasing during the process, and upgraded biogas could reach the requirement of vehicle fuel produced at last, which contain methane more than 95% and CO₂ less than 3%. Conclusions came from these experiments were laid out below:â‘´It is useful to upgrade biogas through water washing with normal pressure,and the operation demand was low for equipment.but better effect gaven only when the raw biogas flow was slow.the technic could used in the pretreatment of biogas with poor quality. Water pressure was the major factor effected the removal ratio of CO₂, CO₂ removal ratio and solubility under dynamic condition were shown intimate connection with the ratio of gas and water during biogas water scrubbing.⑵No distinctness experiment results were shown between scattered packings and structured packings during the experiment done with traditional scrbber packings. During the operating, the best technic condition to remove CO₂ was water temperature kept 10℃, inlet biogas flowed with the speed of 25 l·min^-1,scrubbing pressure kept 0.6 Mpa,water flowed with the speed of 25 l·min^-1. the best technic condition to got best CO₂ solubility was water temperature kept 10℃, inlet biogas flowed with the speed of 25 l·min^-1,scrubbing pressure kept 0.6 Mpa,water flowed with the speed of 5 l·min^-1. experiment factors affected the results stronger and stronger in the light of water temperature, inlet biogas flow speed, water flow speed, scrubbing pressure.⑶Better quality biogas were produced when zeolite pellets or active carbon or clay rings used as scrbber packings than ployhedral hollow ball during biogas upgrading through compressed water scrubbing. These packing have adsorbility all and zeolite pellets and active carbon were behaved more better. Besides, more distinguish represented among the packings came with the washing pressure rising.â‘·The dates came from experiment took zeolite pellet as scrubber packings shown certainly advantage compare with those dates abroad from the same biogas upgrading method. The comparation indicated that it has feasibility to enhance CO₂ removal ratio through take zeolite scrubber packings, and the method worth to be done more.⑸There were certainly CH₄ lost when upgrade biogas through compressed water scrubbing, and the recovery rate of CH₄ was mainly affected by scrubbing pressure, higher scrubbing pressure came with lower CH₄ recovery rate.⑹In the two steps upgrading technics of compressed water scrubbing combined dry absorb, CH₄ content in biogas could be enhanced to about 90% after 0.75Mpa water scrubbing, and then it could be enhanced to about 90% after sodium-based dry regenerable sorbent absorb, so the primary experiment aim was reached. vehicle fuel biogas produced in the experiment shown that high quality biogas could be produced in more easy working condition.