Diesel Biodesulfurization Bacteria Filter And Applied Research

A new strain able to convert dibenzothiophene (DBT) into 2-hydroxybyphenyl (HBP)was isolated from the refinery sullage and was identified as Rhodococcus erythropolis TJQ. The effects of the initial pH,carbon source,nitrogen source,various sulfur compounds and desulfurization metabolic product SO₄^2- and 2-HBP on the growth and desulfurization activity of the strain TJQ was studied. A pint-sized desulfurization bioreactor was designed and the desulfurization activity of the strain in the reactor for different systems of sulfur was studied which was considered as a reference for the industrialized development of the biodesulfurization.1. The optimal initial pH for the growth of the strain varies from 6.0 to 7.0. The activity of TJQ's growth and desulfurization can be improved when regulate the pH value in 6.0⁷.0. The TJQ was able to enhance the produce ratio of 2-HBP from 22.98mg/L(0.135mmol/L) to 31.66mg/L(0.186mmol/L) in aqueous media with 6.4mg/L(0.2mmol/L) DBT as the initial sulfur source during three days ,in this case the produce ratio of 2-HBP increased by 35% .2. The best carbon source and nitrogen source are glucose and ammonium chloride,respectively by 20g/L and 1g/L . The strain TJQ can use multiform sulfur as sulfur source while the sodium sulfate(Na₂SO₄) and the dimethylsulfoxide(DMSO) were the best,so replacing the high-priced organic sulfur source with the low-cost inorganic sulfur source(e.g. Na₂SO₄) was a feasible way to cultivate the strain.3. The TJQ cultivated with the sodium sulfate can effectively desulfurize benzothiophene (BT), DBT and its derivatives 4,6-dimethyldibenzothiophene (4,6-DMDBT).Besides,it can desulfurize the phenyl sulfide (PS). The TJQ cells can remarkably desulfurize the thiophene (TH) sulfur from 100mg/L to 3.6 mg/L , the BT sulfur from 207.1mg/L tol35 mg/L , the DBT sulfur from 150mg/L to 20mg/L, the 4,6-DMDBT sulfur from 100mg/L to 1.6mg/L ,the PS sulfur from 100mg/L to 52mg/L, the desulfurization ratio respectively is 96.4%,34.8%,86.7%,98.4%,48% in the model oil (n-hexadecane containing different organic sulfur compound as the sole sulfur source). When a hydrodesulfurized diesel oil with various organic sulfur compounds were treated with the TJQ resting cells and circled three times ,the total sulfur content significantly decreased from 554mg/L to 267mg/L for diesel oil,the desulfurization ratio is 51.8% .4. The effects of the desulfurization metabolic product SO₄^2- and 2-HBP on the activity of the TJQ growth and desulfurization were studied .The existing of the SO₄^2- can offer the vegetal sulfur source to TJQ ,but it will delay the desulfurization time limit; The resting cells cultivated with Sodium sulfate can effectively desulfurize various organic sulfur compounds. The produce ratio of 2-HBP was enhanced from 1.34mg/L(0.0079mmol/L) to 33.74mg/L(0.1982mmol/L) in aqueous media with 12.8mg/L(0.4mmol/L) DBT as the initial sulfur source when sulfate reducing bacteria or the strain PYS was added to remove the SO₄^2- to enhance the desulfurization ratio of the TJQ. The produce ratio of 2-HBP can be enhanced and the desulfurization ratio of the DBT was 100%.5. A new desulfurization bioreactor of the fuel oils was designed.The TJQ can grow well with high concentration of DBT In the bioreactor, it can desulfurize the DBT sulfur significantly from 19.2mg/L(0.6mmol/L) to 0.224mg/L(0.007mmol/L) ,and the desulfurization ratio is 98.8% in aqueous media during two days .It can desulfurize the DBT sulfur in the model oil (n-hexadecane containing DBT as the sole sulfur source) from 463 mg/L to 396mg/L and the desulfurization ratio is 14.5% during one day. It was able to remove 12.3% of the sulfur in the...