The main objectives for the work were to identify the impurities or components in CTO and TOP causing fouling of hot surfaces to study how process conditions affect fouling , and if processing has beneficial effect on fouling rate.
During literature study, it became obvious that information about detailed fouling mecha-nisms and compounds causing fouling in CTO and TOP samples is scarce. Some fouling studies conducted for upstream processes, mainly pulp mill evaporators, gave distinct hints what could be expected to be found on heater surfaces with tall oil based feeds. Eventually these similar depositions and impurities (lignin, calcium, potassium, sulphate- and phosphate salts) were also found in the analysed deposits during the experimental part.
During literature review some options to prevent fouling was identified. Two most interest-ing methods was coatinterest-ings and modifyinterest-ing the metallic material itself. Quite fast it came clear that coatings as such, traditionally applied on surface of material by brushing or spraying, are not suitable for the targeted temperature range. However, many interesting new materials modification methods were found that are suitable for high temperature applications and demonstrated promising results on earlier studies.
In the experimental part, fouling tendency of different CTO and TOP samples were deter-mined with a lab scale Falex fouling equipment. Two fouling modes were identified and during further tests the overall contribution of each mode for overall fouling resistance could be evaluated. The visible hard deposition layer formed on the hottest spot of test equipment had surprisingly small effect on overall fouling resistance, when a loosely attached gel-like layer had a dominant effect on overall fouling resistance. Also, it was confirmed that there are feasible ways for processing the tall oil based feeds in a manner that significantly reduces or even diminishes the fouling of heat transfer surfaces.
Eventually, it was also verified that lowering the surface temperature or increasing the flow velocity reduced fouling rate, as could be expected based on literature. Flow speed and flow conditions play major role on fouling and, as during experimental part all tests were per-formed at very low flow speeds and at laminar flow region, high turbulence high shear rate tests should be conducted to develop empirical information about fouling under more real-istic flow conditions.
Even though similar amount of in-organic impurities was present in feed, the fouling rates of samples was way different, hence predicting that overall fouling resistance of tall oil based feeds based on impurity levels seems impossible.
For coming experiments, it would be recommended to perform a test series where the focus would be on what was left inside the heater rod assembly after the test and especially iden-tifying and quaniden-tifying the gel-like layer composition to get better understanding of the foul-ing mechanism. For actual experiments, it could be organized so that pure feed is analysed with FTIR. Clean heater rod assembly can be weighted before test run and after the test run to know how much depositions was left inside of the heater rod assembly after draining it in the oven. Then the material remaining inside of the heater rod assembly could be dissolved and analysed with FTIR. When FTIR has the reference sample of the feed it could identify and quantify the changes in compounds left inside of the rod assembly after the test.
Possible other more sensitive analysis methods to analyse the deposits could be ESI-MS and time-of-flight secondary ion mass spectrometry (ToF-SIMS). ESI-MS could identify the ac-tual molecules on depositions, when ToF-SIMS could reveal in depth profile on elemental composition of the remaining solid deposition. Also, better understanding is needed about the attractive forces between the heat transfer surface and the identified foulants in order to choose the most effective fouling mitigation strategies.
References
Aro T., Fatehi P., 2017, Tall oil production from black liquor: Challenges and opportunities.
Separation and Purification Technology, vol. 175. Pp. 469–480
ASTM Standard D5453-19a, 2019, Standard Test Method For Determination Of Total Sul-fur In Light Hydrocarbons, Spark Ignition Engine Fuel, Diesel Engine Fuel, And Engine Oil By Ultraviolet Fluorescence, ASTM International
ASTM Standard D5762-18a, 2018, Standard Test Method for Nitrogen in Liquid Hydrocar-bons, Petroleum and Petroleum Products by Boat-Inlet Chemiluminescence, ASTM Interna-tional
Ang, W., S., Menachem, E., 2008, Fatty Acid Fouling of Reverse Osmosis Membranes: Im-plications for Wastewater Reclamation, Water research (Oxford) 42.16: 4393–4403.
Awad, M., M., 2011, Fouling of Heat Transfer Surfaces, Heat Transfer - Theoretical Analy-sis, Experimental Investigations and Industrial Systems, Prof. Aziz Belmiloudi (Ed.), InTech, Available from: http://www.intechopen.com/books/heat-transfer-theoretical-analy-sis-experimental-investigations-and-industrial-systems/fouling-of-heat-transfer-surfaes Bagby, M.O., Johnson, R.W., Jr., Daniels, R.W., Contrell, R.R., Sauer, E.T., Keenan, M.J., Krevalis, M.A. and Updated By Staff, (2003). Carboxylic Acids. In Kirk-Othmer Encyclo-pedia of Chemical Technology, John Wiley & Sons, Inc (Ed.). https://doi.org/10.1002/0471238961.1921182202010702.a01.pub2
Bansal, B.,, Chen, X., D., Müller-Steinhagen, H., 2007, Analysis of ‘classical’ deposition rate law for crystallisation fouling, Chemical Engineering and Processing 47 (2008) 1201–
1210
CEN/TR 16680, 2014, Liquid petroleum products - Investigation on internal diesel injector sticking deposits mechanisms and the impacts of corrosion inhibitors, Technical Committee CEN/TC 19 “Gaseous and liquid fuels, lubricants and related products of petroleum, syn-thetic and biological origin”
Chimec, 2021, Refining and Process Treatments Technologies – Product catalog, [webpage], [Referred 20.12.2021]. Available: http://www.chimec.com/wp-content/up-loads/2015/04/scheda_A4_process_UTP_WEB.pdf
Class, J.B., 2010, Resins, Natural. In Kirk-Othmer Encyclopedia of Chemical Technology, (Ed.). https://doi.org/10.1002/0471238961.1805190903120119.a01.pub2
Drew J., Propst M., 1981, Tall Oil : a Book on the processing and use of tall oil, for chemist, engineers, managers and producers, Pulp Chemicals Association, New York
EN ISO 20846, 2019, Petroleum products. Determination of sulfur content of automotive fuels. Ultraviolet fluorescence method, CEN/TC 19 Gaseous and liquid fuels, lubricants and related products of petroleum, synthetic and biological origin.
Falex 450 - Falex Thermal Fouling tester (FT2), Falex Corporation, Operation and mainte-nance manual version 2.0
Forchem, 2021, Tall Oil Fatty Acid (TOFA), [webpage], [Referred 17.11.2021], Available:
https://www.forchem.com/products/tall-oil-fatty-acid-tofa/
Forchem, 2011, FORTOP600 Product Datasheet, [webpage], [Referred 14.12.2021], Avai-lable: https://www.forchem.com/products/fortop600/
EU CTO – Added value study, 2016; Analysis of the European Crude Tall Oil industry – Environmental impact, socio-economic value & Downstream potential, Fraunhofer Institute for Environmental, Safety and Energy technology UMSICHT, Oberhausen, Germany, avail-able: https://www.harrpa.eu/images/Publications/EU_CTO_Added_Value_Study_Fin.pdf Huibers, D.T.A, 2000, Tall Oil, Kirk-Othmer Encyclopedia of Chemical Technology, 4th edition, Wiley online library. https://doi.org/10.1002/0471238961.2001121208210902.a01 Holmbom, B., Erä, V., 1978, Composition of tall oil pitch. Journal of Am Oil Chem Soc 55, 342–344. https://doi.org/10.1007/BF02669926
IAEA, 2000, Surface modification of materials by ion implantations for industrial and med-ical applications, Industrial applications and Chemistry, IAEA-TECDOC-1165, Interna-tional atomic energy agency, Vienna, Austria
Javaid, A., Ryan, T., Berg, G., Pan, X., Vispute, T., Bhatia, S., Huber, G., Ford, D., M., 2010, Removal of Char Particles from Fast Pyrolysis Bio-Oil by Microfiltration, Journal of membrane science 363.1: 120–127.
Kang, H. K et al., 2011, Numerical and Experimental Analyses of Anti-Fouling and Heat Transfer in the Heat Exchanger with Circulating Fluidized Bed, Canadian journal of chemi-cal engineering 89.2 : 240–253.
Karlsson, E. et al., 2013, Crystallization Fouling of Sodium Salts in Black Liquor Falling Film Evaporators – Development of Experimental Method and First Results, Nordic pulp &
paper research 28.4 (2013): 506–513.
Knothe, G., 2002, Structure indices in FA chemistry. How relevant is the iodine value?. J Amer Oil Chem Soc, 79: 847-854. https://doi-org.ezproxy.cc.lut.fi/10.1007/s11746-002-0569-4
Kraton, 2017, SYLVABLEND™ PF60 Product Datasheet, [webpage], [Referred 14.12.2021], Available: https://kraton.com/products/sylvablend.php
Kraton, 2021, SYLFAT™ Tall Oil Fatty Acids, [webpage], [Referred 14.11.2021], Avai-lable: https://kraton.com/products/sylfat.php
Kukulka, D., Leising, P., 2009, Evaluation of Surface Coatings on Heat Exchangers, Chem-ical Engineering Transactions 18, DOI: 10.3303/CET0918128.
Kurzin A. V., Evdokimov A. N., Trifonova A. D., 2014, Desulfurization of Tall Oil Pitch, Russian Journal of Applied Chemistry, Vol. 87, No. 3, pp. 299−302.
https://doi.org/10.1134/S1070427214030094
Lee, J-W., Woonbong H., 2017, Simple fabrication of superoleophobic titanium surfaces via hierarchical microhorn/nanoporous structure growth by chemical acid etching and ano-dization, Journal of Alloys and Compounds, Volume 728, p 966-970.
https://doi.org/10.1016/j.jallcom.2017.09.092
Mattox, D. M., 2018, Foundations of Vacuum Coating Technology (2nd Edition). Elsevier.
https://app.knovel.com/hotlink/pdf/id:kt011PCYN2/foundations-vacuum-coating
Mazerolle, Dillon, Bronson, B., and Kruczek, B., 2021, Experimental Investigation of Foul-ing Remediation Strategies for Cross-Flow Microfiltration of Fast Pyrolysis Bio-Oil, Indus-trial & engineering chemistry research 60.7: 3083–3094.
Mechanical inventions, 2018, Log Mean Temperature Difference (LMTD) Method with Ex-amples, [Referred 14.9.2021] Available: http://mechanicalinventions.blogspot.com
Müller-Steinhagen, H., 2011, Heat Transfer Fouling: 50 Years After the Kern and Seaton Model, Heat Transfer Engineering, 32:1, 1-13, DOI: 10.1080/01457632.2010.505127 Müller-Steinhagen H., Malayeri M. R., Watkinson A. P., 2011, Heat Exchanger Fouling:
Mitigation and cleaning strategies, Heat Transfer Engineering, 32:3-4, 189-196. https://doi-org.ezproxy.cc.lut.fi/10.1080/01457632.2010.503108
Müller-Steinhagen, H., and Zhao Q., 1997, Investigation of Low Fouling Surface Alloys Made by Ion Implantation Technology, Chemical engineering science 52.19, p 3321–3332 Neste Oyj, 2021, Neste internal analysis method, Neste Oyj
Nitsche, M., Gbadamosi, R. O., 2016, Heat exchanger design guide: a practical guide for planning, selecting and designing of shell and tube exchangers, Butterworth-Heinemann Norlin, L-H., 2000, Tall Oil, Ullman’s Encyclopedia of Industrial Chemistry, Wiley Online Library, https://doi-org.ezproxy.cc.lut.fi/10.1002/14356007.a26_057
Nwaeri, M., DeMartini, N., 2021, Effect of Resin and Fatty Acids on Sodium Salt Fouling, Chemical engineering science 246 Pronk, P, C.A Infante Ferreira, and G.J Witkamp, 2009, Prevention of Fouling and Scaling in Stationary and Circulating Liquid–solid Fluidized Bed Heat Exchangers: Particle Impact Measurements and Analysis, International journal of heat and mass transfer 52.15: 3857–3868.
Quigley, R., Barbour, R.H., Fahey, E., Lubrizol, Arters, D.C., & Wetzel, W.C., 2010, A Study of the Internal Diesel Injector Deposit Phenomenon.
Rej, D.J, and R.B Alexander, 1994, Cost Estimates For Commercial Plasma Source Ion Im-plantation, Proceedings of 1994 IEEE 21st International Conference on Plasma Sciences (ICOPS). IEEE, 1994. 94–95.
Rohr JJ., Latz M., Fallon S., Nauen J., Hendricks, E., 1998, Experimental approaches to-wards interpreting dolphin-stimulated bioluminescence. The Journal of experimental biol-ogy 201. p 1450.
Saari J., 2010, Heat Exchanger Thermal Design Guide, LUT University, Faculty of Tech-nology
Shankar V., Chhabra R.P., 2017, Coulson and Richardson's chemical engineering, Volume 1B - Heat and mass transfer – Fundamentals and applications, 7th edition, Butterworth-Heinemann
Santos, O. et al., 2004, Modified Stainless Steel Surfaces Targeted to Reduce Fouling––
surface Characterization, Journal of food engineering 64.1: p 63–79.
Stephenson, T., Hazelton, M., Kupsta, M., Lepore, J., Andreassen, E., J., Hoff, A., Newman, B., Eaton, P., Gray, M., Mitlin, D., 2015, Tiophene mitigates high temperature fouling of metal surfaces in oil refining, Fuel, Volume 139, pages 411-424,
Tikka, P., 2008, Papermaking Science and Technology: Book 6, Chemical Pulping. Part 2, Recovery of Chemicals and Energy. 2nd ed., totally updated version. Helsinki: Finnish Paper Engineers’ Association
Ullmann, J., Geduldig, M., Stutzenberger, H,. Caprotti, R., Balfour, G., 2008, Investigation into the Formation and Prevention of Internal Diesel Injector Deposits. SAE Technical Paper Series, 2008-01-0926
Venkateshan S.P, 2021, Heat Transfer, 3rd edition, Springer eBooks
Zhao, P., et al., 2016, Fatty Acid Fouling of Forward Osmosis membrane：Effects of pH,calcium,membrane orientation,initial permeate flux and foulant composition, Journal of environmental sciences (China) 46.8 (2016): 55–62.
Zohuri, B., 2017, Compact Heat Exchangers Design for the Process Industry.
https://doi.org/10.1007/978-3-319-29835-1_3