Nashrieh Shimi va Mohandesi Shimi Iran

Nashrieh Shimi va Mohandesi Shimi Iran

Determination of Nitrogen Content in Crude Oil and Petroleum Products of Isfahan Refinery by Three Techniques of Titration, pH Metric Titration and Nessler and Comparison of Their Results

Document Type : Research Article

Authors
Massoud Kaykhaii 1
Mashaallah Rahmani 1
Mohsen Moradmand 2
Mojtaba Sadrarhami 1
1 Department of Chemistry, Faculty of Sciences, University of Sistan and Baluchestan,, Zahedan, I.R. IRAN
2 Isfahan Refinery, Central Lab, Isfahan, I.R. IRAN
Abstract
In this study, the Nitrogen content of crude oil and petroleum products of Isfahan refinery were determined using three methods of pH meter titration, Nessler method, and titration with sulfuric acid. Results were compared in terms of accuracy and precision. In the first method (pH metric titration), samples were digested by concentrated sulfuric acid and distilled by micro-Kjeldahl apparatus and
the distillate was titrated using a pH meter. In the second method (Nessler) samples were distilled using the micro-Kjeldahl apparatus and were measured spectrophotometrically utilizing Nessler reagent. The third technique was based on a combination of micro-Kjeldahl distillation by sulphuric acid and direct titration in the presence of methyl red indicator. For a lighter portion of the crude oil, a primary
 liquid-liquid extraction step in a separatory funnel by sulphuric acid was performed. Statistical results showed that all three methods have the same accuracy. Analysis time for direct titration is the most time-consuming method, while Nessler was the shortest. However, Nessler is the most complicated technique among others. According to the results obtained by Nessler, the nitrogen content of oil feed was between 1.0 to 1.3 g/.L, while it was at the range of 0.1 to 4300.0 mg/.L in petroleum products which is in the normal global range. Finally, statistical analysis showed that pH metric titration method is
a proper technique for such applications with relatively good reproducibility. The Nessler-photometric method is also satisfactory, especially for low nitrogen content samples, but its precision is lower than the former method. Direct titration has the worst precision among three methods.
Keywords
Nitrogen assay
Micro-Kjeldahl
Oil Compounds
Nessler
Titration

Subjects

[1] Gaffney J.S., Marley N.A., The Impacts of Combustion Emissions on Air Quality and Climate – From Coal to Biofuels and Beyond., Atmospheric Environment, 43(1): 23–36 (2009).
[2] Maruthamuthu S., Mohanan S., Rajasekar A., Muthukumar N., Ponmarippan S., Subramanian P., Palaniswamy N., Role of Corrosion Inhibitor on Bacterial Corrosion in Petroleum Product Pipelines., Indian Journal of Chemical Technology, 12(5): 567-575 (2005).
[3] Campins-Falco P.,  Meseguer-Lloret S., Climent-Santamaria T.,  Molins-Legua C., A Microscale Kjeldahl Nitrogen Determination for Environmental Waters., Talanta, 75(4): 1123–1126 (2008).
[4]  Li Y., Chen Y., Wu C.Y., Tang X., Ji  X.J., Determination of Optimum Nitrogen Application Rates in Zhejiang Province, China, Based on Rice Yields and Ecological Security., Journal of Integrative Agriculture,  14(12):  2426-2433 (2015).
[5] Singh D., Chopra A., Patel M.B, Sarpal A.S., A Comparative Evaluation of Nitrogen Compounds in Petroleum Distillates.,Chromatographia, 74(1): 121-126 (2011).   
[6] Zhan T.L.T., Guan  C., Xie. H.J., Chen Y.M., Vertical Migration of Leachate Pollutants in Clayey Soils Beneath an Uncontrolled Landfill at Huainan., Science of The Total Environment, 471: 290–298 (2014).
[7] Mckenzie H.A., The Kjeldahl Determination of Nitrogen: Retrospect and Prospect., Trends in Analytical Chemistry, 13(4): 138-144 (1994).
[8] Zhang L., Li L., Ma C., Ge S., Yan M., Bian C., Detection of α-Fetoprotein with an Ultrasensitive Electrochemiluminescence Paper Device Based on Green-Luminescent Nitrogen-Doped Graphene Quantum Dots., Sensors and Actuators B: Chemical, 221: 799–806 (2015).
[9] Wang X., Lin J.M., Liu M.L., Cheng X.L., Flow-based Luminescence-Sensing Methods for Environmental Water Analysis., Trends in Analytical Chemistry, 28: 75–87 (2009).
[10] Templeton D.W., Laurens L., Nitrogen-to-Protein Conversion Factors Revisited for Applications of Microalgal Biomass Conversion to Food, Feed and Fuel., Algal Research, 11: 359–367 (2015).
[11] Pontes F.V., Carneiro M.C., Vaitsman D.S., da Rocha G.P., Neto A.A., da Silva L.L., Monteiro M.L., Simplified Version of the Total Kjeldahl Nitrogen Method Using an Ammonia Extraction Ultrasound-Assisted Purge-and-Trap System and Ion Chromatography for Analyses of Geological Samples., Analytica Chimica Acta, 632(2):  284–288 (2009).
[12] Agbede J.O., Aletor V.A., Chemical Characterization and Protein Quality Evaluation of Leaf Protein Concentrates from Glyricidia Sepium and Leucaena Leucocephala., Journal of Food Science & Technology, 39(3): 253-261 (2004).
[13] Morrison G.R., Microchemical Determination of Organic Nitrogen with Nessler Reagent., Analytical Biochemistry, 43(2): 527-532 (1971).
[14] Zhou L., Boyd C.E., Comparison of Nessler, Phenate, Salicylate and Ion Selective Electrode Procedures for Determination of Total Ammonia Nitrogen in Aquaculture., Aquaculture, 450: 187-193 (2016).
[15] Casalta E., Salmon J.M., Sablayrolles J.M., Comparison of Different Methods for the Determination of Assimilable Nitrogen in Grape Musts., Journal of Food Science and Technology, 54: 271-277 (2013).
[16] Bojana B., Jovana M., Ivan M., Jovanov P., Misan A., Saric L., Rapid Method for Determination of Protein Content in Cereals and Oilseeds: Validation, Measurement Uncertainty and Comparison with the Kjeldahl Method., Accreditation and Quality Assurance, 15(10): 555-561 (2010).
[17] Pavlova A., Dobrev D.S., Ivanova P., Determination of Total Nitrogen Content by Different Approaches in Petroleum Matrices., Journal of Fuel, 88: 27-30. (2009).
[18] Mohidin H., Hanafi M.M., Rafli Y.M., Abdullah S.N.A., Idris A.S., Man S., Idris J., Sahebi M., Determination of Optimum Levels of Nitrogen, Phosphorus and Potassium of Oil Palm Seedlings in Solution Culture., Journal of Bragantia, 74: 3-7 (2015).