The Research On Simultaneous Desulfurification And Denitrification H₂S Treatment Process And Its Application In Oil Gathering And Transferring System

Simultaneous desulfurification and denitrification is an process that sulfur bacteriametabolism autophagy sulfur ions, or denitrifying bacteria which can restrain sulfatereducting bacteria (SRB) propagation to complete eliminating sulfuretted hydrogen.According to the problems of oilfield gathering system roots in biological metabolismon damaging and wide spreading, the research on application of simultaneousdesulfurification and denitrification technology will offer sustainable developmenttheory and technology support for oil field to clean up stench environment mainlyleaded by sulfuretted hydrogen.Two stages of UASB in series simultaneous desulfurification and denitrificationcraft system have been built. The first stage is the reactor releasing hydrogen sulfide gasby sulfate reducing bacteria metabolic to analog oil field’s actual production process; thesecond stage reactor on the occasion of sodium nitrite is induced by denitrifyingbacteria inhibition of hydrogen sulfide to reach the goal of synchronousdesulphurization denitrification inhibition of hydrogen sulphide. The result reveals thatthe process could successfully start within80days. When the reactor starts, both thefirst stage reactor’s sulfuretted hydrogen percent conversion and the hydrogen sulfide removal rate in second stage reactor could boost above90%. At the same time, thesulfate reducing bacteria in first stage reactor will increase810000cfu/mL. And thedenitrifying bacteria concentration in second stage reactor add up to about 800000cfu/mL,at mean while, the number of SRB bacterium is declining to100cfu/mL.In process of reactor starts, both two stage reactors’ sludge types changes, theprimal floc type sludge gradually become granular sludge, and the sludge in secondstage reactor changes black into milk white. The results show that granular sludge’soperation effects are better than cotton-shaped sludge no matter in the first or the secondstage reactor. The main factor of granular sludge in first stage reactor is sulfuric acidroot ion concentration and the second reactor’s is the dosage and reflux flow of sodiumnitrite. In the first stage reactor, concentration of sulfuric acid root is higher than1500mg/L, and sodium nitrite’s dosage is more than40g in the second stage reactor, thereflux flow is more than60L/h, in this system（chinglish）, sludge’s diameter is themaximal, and the first stage reactor’s diameter can be600μm and the second stagereactor’s diameter can be140μm. The best simultaneous desulfurification anddenitrification operation effects are under the above diameters. Further granularsludge crushing and refining on the system, in the first stage reactor, the sulfatereducting bacteria is mainly desulfobacter and a handful of micrococcus; in secondreactor, denitrifying bacteria is heterotrophic denitrifying bacteria. Its form likeequilateral triangle and its length is4.58μm.To embed-biology and strengthen biography effects of simultaneousdesulfurification and denitrification’s granular sludge produced in second stage reactor.,and apply for it in spot. The research shows that embed-biology balls can be alive forthree days when leaves the system, and after putting it in gathering and transportationsystem18days, the denitrifying bacteria content will increase from1100cfu/mL toabout800000cfu/mL, and concentration of hydrogen sulfide will decrease from150mg/m3to10mg/m3，all above are reach national standard (GBZ2-2002). It provesfeasibility of treatment of sulfuretted hydrogen simultaneous desulfurification anddenitrification can be used in oil fields.