|

Technical Lignosulfonates Effect on Weld Corrosion in a Coal-Water Slurry

Authors: Shelontsev V.A., Gorichev I.G., Kuzin A.V., Eliseeva E.A. Published: 11.10.2019
Published in issue: #5(86)/2019  
DOI: 10.18698/1812-3368-2019-5-89-98

 
Category: Chemistry | Chapter: Physical Chemistry  
Keywords: technical lignosulfonate, corrosion, weld, coal-water slurry, macro-galvanic couple

Hydrotransport of coal, iron ore, bauxite and other solid materials is known to be carried out through trunk pipelines. Hydrotransport of coal in the form of highly concentrated coal-water slurries (HCCWS) makes it possible to solve a whole range of problems from environmental ones to those when HCCWS are used as a fuel for energy boilers. The HCCWS combustion efficiency is determined by the concentration of the solid pulp phase and the particle size. The highest HCCWS combustion efficiency is observed when the mass concentration of the solid phase is 60--65 % and the particle size is up to 0.02 sm. In order to achieve stability of these slurries with the solid phase concentration, various additives are used to improve the rheological properties of coal-water slurries. In particular, such plasticizing agents as sodium tripolyphosphate, technical lignosulfonates, carbon-alkaline reagents and others are used. Plasticizing agents are known to change the rheological properties of coal-water slurries but the problems of corrosion activity of plasticizing agents are not well understood, especially with respect to welded joints of pipelines. Welded joints of slurry pipelines can be represented as macro-galvanic couples, in which the weld and base metal are electrodes of a galvanic element. The current magnitude of the macro-galvanic couple can be used to calculate the local corrosion value due to the work of the galvanic element of the base metal and the weld. The paper studies the effect of technical lignosulfonates (TLS) and TLS-based compositions in a coal-water slurry on the local currents of the base metal --- weld macro-galvanic couple made of 09G2S steel. Findings of research show that in the water-coal slurry the maximum inhibitory effect is observed when 0.75 % TLS + 0.25 % K2CrO4 (Na2CO3) is added to the slurry

References

[1] Khodakov G.S. Coal-water suspensions in power engineering. Therm. Eng., 2007, vol. 54, iss. 1, pp. 36--47. DOI: https://doi.org/10.1134/S0040601507010077

[2] Khodakov G.S. Rheology suspensions. Theory of phase flow and its experimental justification. Rossiyskiy khimicheskiy zhurnal, 2003, vol. XLVII, no. 2, pp. 33--44 (in Russ.).

[3] Svishchev D.A., Keiko A.V. A thermodynamic analysis of operating conditions under which coal-water fuel is gasified in flow. Therm. Eng., 2010, vol. 57, iss. 6, pp. 490--494. DOI: https://doi.org/10.1134/S0040601510060066

[4] Savitskiy D.P., Makarova K.V., Makarov A.S. Rheological properties of highly concentrated coal suspensions of varying metamorphism degrees in presence of sodium tripolyphosphate. Ukrainskiy khimicheskiy zhurnal [Ukrainian Chemistry Journal], 2011, vol. 77, no. 4, pp. 79--83 (in Russ.).

[5] Savitskii D.P., Makarov A.S. Zavgorodnii V.A. Rheological properties of water-coal slurries based on brown coal in the presence of sodium lignosulfonates and alkali. Solid Fuel Chem., 2009, vol. 43, iss. 5, pp. 328--332. DOI: https://doi.org/10.3103/S0361521909050127

[6] Kusanynov K., Alpysova G.K., Tanasheva N.K., et al. Influence of the plasticizer reactant on properties of coal-water fuel synthesized based on the electrohydroimpulse technology. Tomsk State University Journal of Mathematics and Mechanics, 2014, no. 6 (32), pp. 80--85 (in Russ.).

[7] Mosa E.S., Saleh A.M., Taha T.A. Effect of chemical additives on flow characteristics of coal slurries. Physicochem. Probl. Mi., 2008, vol. 42, pp. 107--118.

[8] Zvereva E.R., Akhmetvalieva G.R., Makarova A.O., et al. Alteration of coal-water fuel rheological properties in the presence of nanomaterials. Vestnik KGEU, 2017, no. 3 (35), pp. 76--83 (in Russ.).

[9] Baranova M.P. Tekhnologiya polucheniya i ispolzovaniya toplivnykh vodougolnykh suspenziy iz ugley razlichnoy stepeni metamorfizma. Dis. d-ra. tekh. nauk [Production and application technology of fuel coal-water suspensions of coal with various metamorphism degree. Dr. Sc. (Eng.). Diss.]. Moscow, MEI Publ., 2014.

[10] Isupov V.P., Gorichev I.G., Shelontsev V.A., et al. Concerning effect of hydroxide-ions and chromate-ions on corrosion of carbon steel. Zashchita metallov, 1991, vol. 27, no. 1, pp. 33--39 (in Russ.)

[11] Oreshkin A.Yu., Shlyachkov D.A., Yushkov A.B. Special aspects of corrosion resistance of welded joints at carrying out expert examination on industrial safety of technological equipment of petrochemical and petroleum industry. Part 1. Molodoy uchenyy [Young Scientist], 2015, no. 18, pp. 172--175 (in Russ.).

[12] Bukleshev D.O. Practical study of dependence rate corrosion pipeline welded joints on external factors. Tekhnicheskie nauki --- ot teorii k praktike, 2016, no. 9 (57), pp. 22--32 (in Russ.)

[13] Krivonosova E.A., Akulova S.N., Myshkina A.V. To the problem of corrosion destruction of welded joints. Bulletin PNRPU. Mechanical Engineering, Materials Science, 2017, vol. 19, no. 3, pp. 114--138 (in Russ.).

[14] Kochanov V.A., Danilov Yu.B., Shepil T.E., et al. Corrosion behavior of welded joints of dissimilar steels. Part 1. Laboratory studies. Corrosion: Materials, Protection, 2008, no. 11, pp. 10--16 (in Russ.).

[15] Zhuk N.P. Kurs teorii korrozii i zashchity metallov [Course on theory of metals corrosion and protection]. Moscow, AlyanS Publ., 2014.