With rapidly industrial and agricultural development, more and more fertilizers, chemicals and heavy ions will be discharged into lakes and rivers, which would cause lake eutrophication and quality deterioration in dr...With rapidly industrial and agricultural development, more and more fertilizers, chemicals and heavy ions will be discharged into lakes and rivers, which would cause lake eutrophication and quality deterioration in drinking water sources. Therefore, denitrification is essential for controlling the amounts of nitrogen. During the transformation process from nitrate to the end products\|nitrogen and several intermediates \[e.g. nitrite (NO\+-\-2), nitrous oxide (N\-2O) and nitric oxide (NO)\] may be accumulated, which have more toxic influences on the environment. In this study, the denitrification effect of Paracoccus Denitrificans was examined on the changes between oxic and anoxic conditions at varying pH. At pH=\{7.5\}, denitrification proceeded well after 3 switches from oxic to anoxic conditions and vice versa. Production of N\-2 was constant and the amounts of NO\+-\-2, N\-2O and NO were extremely low. However, at pH=6.8, denitrification activity was inhibited and there were large amounts of the intermediates. The denitrifying bacteria decreased violently in dry weight and were washed out.展开更多
A new kind of solvent for deacidification of distillate oils was introduced in this paper. After successful laboratory study this technology had been applied in commercial scale successfully. Compared to traditional c...A new kind of solvent for deacidification of distillate oils was introduced in this paper. After successful laboratory study this technology had been applied in commercial scale successfully. Compared to traditional caustic wash of distillate oils, this technology has a lot of merits, such as the broad range of distillates to be processed, low caustic consumption, recycle of deacidifying agent, absence of waste caustic discharge, and low equipment revamp expenses, which can have promising perspectives for exploitation and application of this technology.展开更多
The method for refining the straight-run diesel fuel was studied in laboratory scale in order to make the acid number of diesel fraction comply with the standard while removing the naphthenic acids contained in diesel...The method for refining the straight-run diesel fuel was studied in laboratory scale in order to make the acid number of diesel fraction comply with the standard while removing the naphthenic acids contained in diesel without causing environmental pollution. After comparing the effect of refining using three solvents, the isopropyl alcohol-HOA was specified as the best solvent. Meanwhile, the relationship between the acid number of diesel fraction and the amount of solvent used and the relationship between the concentration of solvent and temperature and the stability of diesel in terms of its acid number were also investigated. Experimental results had shown that when the mass fraction of the HOA-IPA solvent was 20% at a dosage of 17 mL of the solvent and a temperature of 30℃, the acid number of the refined diesel fraction was 0.015 mg KOH/g with a good stability of acidity in the diesel fraction.展开更多
文摘With rapidly industrial and agricultural development, more and more fertilizers, chemicals and heavy ions will be discharged into lakes and rivers, which would cause lake eutrophication and quality deterioration in drinking water sources. Therefore, denitrification is essential for controlling the amounts of nitrogen. During the transformation process from nitrate to the end products\|nitrogen and several intermediates \[e.g. nitrite (NO\+-\-2), nitrous oxide (N\-2O) and nitric oxide (NO)\] may be accumulated, which have more toxic influences on the environment. In this study, the denitrification effect of Paracoccus Denitrificans was examined on the changes between oxic and anoxic conditions at varying pH. At pH=\{7.5\}, denitrification proceeded well after 3 switches from oxic to anoxic conditions and vice versa. Production of N\-2 was constant and the amounts of NO\+-\-2, N\-2O and NO were extremely low. However, at pH=6.8, denitrification activity was inhibited and there were large amounts of the intermediates. The denitrifying bacteria decreased violently in dry weight and were washed out.
文摘A new kind of solvent for deacidification of distillate oils was introduced in this paper. After successful laboratory study this technology had been applied in commercial scale successfully. Compared to traditional caustic wash of distillate oils, this technology has a lot of merits, such as the broad range of distillates to be processed, low caustic consumption, recycle of deacidifying agent, absence of waste caustic discharge, and low equipment revamp expenses, which can have promising perspectives for exploitation and application of this technology.
文摘The method for refining the straight-run diesel fuel was studied in laboratory scale in order to make the acid number of diesel fraction comply with the standard while removing the naphthenic acids contained in diesel without causing environmental pollution. After comparing the effect of refining using three solvents, the isopropyl alcohol-HOA was specified as the best solvent. Meanwhile, the relationship between the acid number of diesel fraction and the amount of solvent used and the relationship between the concentration of solvent and temperature and the stability of diesel in terms of its acid number were also investigated. Experimental results had shown that when the mass fraction of the HOA-IPA solvent was 20% at a dosage of 17 mL of the solvent and a temperature of 30℃, the acid number of the refined diesel fraction was 0.015 mg KOH/g with a good stability of acidity in the diesel fraction.
