\ s Aromatics - Nonaromatics
5. EXPERIMENTAL SETUP AND TEST RUNS
The test runs were conducted in a pilot-scale FCC-unit with internal CFB-design as developed by Reichhold et al [10]. Unlike industrial FCC-plants where both riser and regenerator are constructed as separate items, the pilot-scale FCC-plant
integrates both into a compact unit with the riser concentrically mounted inside the regenerator, as shown in Figure 3. The so called Internal CFB-Design improves the heat balance of the operation, with the regenerator providing direct heat for the endothermic cracking reactions in the riser.
product g a s
heating system
Figure 3 : Schematic of the pilot-scale FCC-unit with internal CFB-design
The continuous circulation of bed material between riser and regenerator is ensured by the implementation of a fluidized siphon and bottom section. Both are fluidized with nitrogen as an inert "separation" gas in order to avoid gas leakage from the reactor to the regenerator and vice versa.
Height Riser length Riser diameter Regenerator diameter Catalyst
Catalyst mass Riser temperature Regenerator temperature Feed flow
Catalyst to oil ratio Riser residence time Pressure
2.5 m 1.977 m 0.025 m 0.180 m
shape select. Zeolithe 9 kg
530 °C 610 °C 3.5 l/h 25-27 1s ambient Table 2 : Dimensions and basic operating data of FCC pilot plant
The cracking experiments were conducted with three different mixing ratios of used frying oil with VGO (hydrotreated vacuum gas oil) as the standard FCC-feed. The concentrations of used frying oil in the mixture were 10, 20 and 40 mass percent and the results of these test runs were compared with the Base Case (100% VGO).
Table 3 gives the physical and chemical properties of the VGO used for preparing the different feed mixtures.
Aromatic Carbons
Paraffinic and Naphtenic Carbons Sulphur Table 3 : Properties of hydrotreated vacuum gas oil
Used frying oil for the cracking experiments was obtained from a local used oil collection service and therefore no insight was granted into the origin of the oil or how long the oil had been in use. However, symptoms of both antioxidation as well as polymerization were clearly visible in the oil, making a comparison of the experimental results with results of the "fresh" oil experiments very interesting.
6. RESULTS AND DISCUSSION
All experiments were conducted as continuous test runs, during which all temperatures and pressures in the different zones of the pilot plant were continuously monitored. Measurement of the regenerator flue gas composition allowed for the calculation of the coke yield. The cracking products were separated into a gaseous phase and a liquid phase through condensation and samples of both were collected for GC-analysis at regular intervals. The liquid phase could furthermore be separated into an aqueous and an organic liquid phase, containing the gasoline fraction (<215°C) and cracking residue (215°C<). The aqueous phase, which was formed by cracking of used frying oil was weighed for the mass balance and then discarded. Both product gas as well as organic liquid product were analyzed with gas chromatography to obtain the exact yields of the different gas compounds and the gasoline yield.
The following diagrams in this chapter highlight the results of cracking used frying oil and they are displayed together with the results of previous experiments with rapeseed oil and sunflower oil [5] for comparison. However it has to be pointed out that the test runs with used frying oil were conducted with a higher cracking temperature in the riser (530°C contrary to 500°C in the test runs with "fresh"
biooils) in order to reflect new developments in the FCC-sector, where higher gas yields are desired nowadays. The higher cracking temperature increased the coke and gas yield lowering the gasoline yield as well as the conversion. All these product yields were calculated as relative yields related to the mass of feed and plotted against the ratio of biooil in the feed.
The conversion is defined as sum of the gasoline and gas yield. Figure 4 shows that the conversion is decreased with the addition of used frying oil, from approximately 79.6% to 72.7% when adding 40% of used frying oil to the feed. This apparent decrease in conversion, which is the case for all biooils, can be very well explained by the formation of water and carbon dioxide from the carboxylic groups of the fatty acids and esters. Water and carbon dioxide are not considered as desired products and therefore the conversion is lowered. Taking the oxygen concentration of biooils (approximately 11 mass percent depending on the oil) into account, the calculated absolute decrease in conversion would be 5.4%. Along with the increase in coke production of 1 % (absolute) the conversion should theoretically drop to 73.2% for the runs with 40% of used frying oil, which is a good correlation with the experimental results.
0.820
Oil a Sunflower Oil 0.000 0.050 0.100 0.150 0.200 0.250
Biooil [m-frac]
0.300 0.350 0.400 0.450
Figure 4 : Conversion 0.520
-o Used Frying Oil
— — 8
0.000 0.050 0.100 0.150 0.200 0.250Biooil [m-frac]
0.300 0.350 0.400 0.450
Figure 5 : Gasoline and gas yield
As illustrated in Figure 5, cracking of used frying oil decreases both the gas and gasoline yield. As mentioned earlier the offsets of used frying oil from the "fresh"
biooils are caused by the higher cracking temperature (Base Case at 500°C: 50%
gasoline, Base Case at 530°C: 46% gasoline). Yet the effect of the biooil on the gas yield is much stronger when used frying oil is added to the feed, than it is with
"fresh" rapeseed and sunflower oil. The gas yield is lowered from 33.7% to 29.1% in these test runs. This behavior is due to the presence of free fatty acids, water, aldehyds and ketones in the used frying oil. These substances are mid-products of the deoxygenation-pathway (refer to chapter 4) and favour condensation and polymerization reactions, leading to an increased coke and water yield. In return,
addition of biooils to the FCC-feedstock. Used frying oil, which can be assumed to be a degraded sunflower oil, shows a higher increase in coke production (from 4.8 to 5.3% in runs with 40% of biooil) and a slightly higher water yield than its origin.
0.057
0.052
0.047
Coke
Used Frying Oil • Rapeseed Oil • Sunflower Oil
0.027
Water
0.022 0.000
0.080
0.070
0.060
0.050
0.040 2
• > .
0.030 I
0.020
o.oio
0.000 0.050 0.100 0.150 0.200 0.250
Biooil [m-frac]
0.300 0.350 0.400 0.450
Figure 6 : Coke and water yield
30000
0
0.000 0.050 0.100 0.150 0.200 0.250 0.300 0.350 0.400 0.450 Biooil [m-frac]
Figure 7 : NOx and carbon monoxide emissions in regenerator flue gas
The influence of used frying oil on the emissions of nitrogen oxide and carbon monoxide in the regenerator flue gas is illustrated in Figure 7. Since biooils do not
contain any nitrogen compounds, NOx-emissions were significantly reduced to 17ppm with increasing ratio of used frying oil in the feedstock. Emissions of CO were increased because of the higher amounts of coke formed on the catalyst and their subsequent combustion in the regenerator where available amounts of oxygen were limited. CO emissions of the specific FCC-pilot plant used for these test runs are generally higher due to the lower regeneration temperature compared to commercial FCC-units (610°C as opposite to 750°C).
7. CONCLUSION
The main objective of this work, adding up to 40% of used frying oil to the standard feedstock of a pilot-scale FCC-unit could successfully be completed. The continuous test runs could be conducted without any prior modifications to the pilot plant and without experiencing any difficulties with the system. Results indicated that the addition of used frying oil leads to a decrease in conversion due to the formation of water and carbon dioxide originating from the carboxylic groups of the fatty acids and esters in the biooil. Also an increase in coke yield could be observed, which resulted in an increase of CO emissions in the regenerator flue gas because of limited availability of oxygen during coke combustion. On the other hand, NOx-emissions could significantly be reduced with the addition of the frying oil. The results of these experiments were compared to preliminary experiments with "fresh" rapeseed oil and sunflower oil and the findings were similar. Slight differences in the gas and coke yield could be explained very well by structure modifications of the biooil during the frying process. Overall it can be stated that catalytic cracking could be an interesting and feasible alternative recycling procedure for used frying oils.
8. REFERENCES
[1] Salmhofer C , Strasser A.; "Altspeiseöl gehört in eine Biogasanlage - nicht in den Kanal", press note, Klimabündnis Kärnten (2002)
[2] United States Department of Agriculture, Economic Research Service, Market and Trade Economics Division; "Oil Crops Situation and Outlook Yearbook", OCS 2000 (October 2000) [3] World Health Organization, Biotech Consult (May 2002)
[4] Erasmus U.; "Fats that Heal, Fats that Kill: The Complete Guide to Fats, Oils, Cholesterol and Human Health", Alive Books (1999), ISBN:0920470386
[5] Reichhold A., Strauss T., Ramakrishnan C ; "Oils From Biological Sources As Possible Feed-stocks for FCC-Processes", Proa, 7th Circulating Fluidized Bed Technology Conference, Niagara Falls, Canada, 5-8 May 2002, p.913-920
[6] Gertz, C ; "Veränderung von Fetten und Ölen beim Erhitzen und bei der Lagerung", publication, Deutsche Gesellschaft für Fettwissenschaft (2000)
[7] Adjaye J.D., Bakhshi N.N.; "Catalytic Conversion of a Biomass-derived Oil to Fuels and Chemicals I: model compound studies and reaction pathways", Biomass and Bioenergy, Vol.8, No.3, (1995), pp.131-149
[8] Idem R.O., Katikaneni S.P.R., Bakhshi N.N.; "Catalytic Conversion of Canola Oil to Fuels and Chemicals: Roles of Catalyst Acidity, Basicity and Shape Selectivity on Product Distribution", Fuel Processing Technology 51 (1997), p.101-125
[9] Dandik L , Aksoy H.A.; "Pyrolysis of Used Sunflower Oil in the Presence of Sodium Carbonate by Using Fractionating Pyrolysis Reactor", Fuel Processing Technology 57, (1998), p.81-92
M01 Reichhold A., Hofbauer H., Krobath P.; "Internally Circulating Fluidized Bed as a Reaction/
Regeneration System for Catalytic Cracking", Circulating Fluidized Bed Technology Conference, Beijing (1996), pp.414-419
DIPL.-ING. CHANDRASEKHAR RAMAKRISHNAN
PERSÖNLICHE ANGABEN:
Familienstand:
Staatsbürgerschaft:
Geburtsdatum:
Geburtsort:
Familie: Vater Mutter Schwester
ledig Österreich 09.09.1974 Wien, XII
Dipl.-Ing. Dr. tech. Sundaresa Ramakrishnan Gizella Ramakrishnan
Mag. iur. Meera Ramakrishnan
AUSBILDUNG:
1984-1992 Juni 1992 1992-2000 November 2000 2001-2004
Bundesrealgymnasium, Wien V
Reifeprüfung mit ausgezeichnetem Erfolg
Studium der Technischen Chemie, Technische Universität Wien Abschluss des Studiums mit Auszeichnung als Dipl.-Ing.
Doktoratstudium der technischen Wissenschaften mit Doktorarbeit am Institut für Verfahrenstechnik
SPRACHKENNTNISSE:
Englisch: verhandlungsfähig Ungarisch: verhandlungsfahig Französisch: Anfängerkenntnisse Italienisch: Anfängerkenntnisse
Dipl.-Ing. Chandrasekhar Ramakrishnan
TÄTIGKEITEN WÄHREND DES STUDIUMS:
• 1993-1999
Regelmäßige Ferialpraktika und Aushilfstätigkeiten als Chemiker bei der Octapharma Pharmazeutika Produktionsges.m.b.H, Wien X, in der Abteilung Qualitätskontrolle Arbeitsbereiche: Nasschemie, Elektrophorese, HPLC, GC, Headspace-GC,
Überprüfung sämtlicher Geräte auf Y2K-Tauglichkeit, Validierungen Interne Schulungen: GMP / GLP, Hygiene in Reinräumen
- Jan. 1998-Mai 1999
Beschäftigung über Adecco Personalbereitstellungs-GmbH, bei:
Europcar Autovermietung Österreich, Stadtbüro Wien bzw. Flughafen VIE Denzel Autovertriebsges.m.b.H. Wien
ARBEITSPRAXIS NACH ABSCHLUSS DES STUDIUMS:
• Juni 2000 bis Jänner 2003
Forschungsassistent am Institut für Verfahrenstechnik, Umwelttechnik und technische Biowissenschaften, Technische Universität Wien
Arbeitsgruppe: Wirbelschichtsysteme und Raffinerietechnik
Tätigkeiten: diverse Forschungsarbeiten aus dem Bereich FCC, Wirbelschichttechnik, Luftreinhaltung, Raffinerietechnik allgemein, Projekte für OMV AG und Linde AG
• Oktober 2000 bis Juni 2002
Studienassistent an der Technischen Universität Wien
Schwerpunkte: Studentenbetreuung, Brennstofftechnologie, ehem. Reaktionstechnik
• Juli 2002 bis August 2002
Übungs- und Studentenbetreuer in engl. Sprache bei der Vienna Chemical Engineering Summer-School 2002 für den Bereich Reaction Engineering
• Februar 2003 bis Jänner 2004
Zivildienst beim Verein Multikulturelles Netzwerk im Bereich der Betreuung von sozial benachteiligten Jugendlichen, Wien VII
Tätigkeiten: Buchhaltung, Verwaltung der Finanzen, Betreuung der Computersysteme und des Multimedia-Bereiches, Mithilfe bei der Planung und Abhaltung von PR-Events, Parkbetreuung von Kindern und Jugendlichen
" März 2003 bis heute
Verfahrenstechniker bei der Tecon Engineering GmbH
Basic und Detail Engineering verschiedener Prozesse und Anlagen
Wirtschaftlichkeitsanalysen und Machbarkeitsstudien, Projektmanagement
ARBEITEN UND PUBLIKATIONEN:
Ramakrishnan, C ; „Optimierang einer FCC-Anlage durch den Einsatz von Liftgas im Riser und Sauerstoffanreicherung im Regenerator", Diplomarbeit, TU-Wien, Institut für Verfahrenstechnik, Brennstofftechnik und Umwelttechnik (2000) Reichhold A., Strauß T., Ramakrishnan C , Hofbauer H.; "Oxygen Enrichment in an Internally Circulating Fluidized Bed System for Catalytic Cracking",
Fluidization X, Beijing, proceedings (2001)
Reichhold A., Strauß T., Ramakrishnan C ; "Oils from Biological Sources as Possible Feedstock for FCC-Processes", CFB-7, Niagara Falls, Canada, pp 913-920 (2002)
Ramakrishnan, C ; „Umfassende Untersuchungen zur katalytischen Konversion von Bioölen in einer vollkontinuierlichen FCC-Technikumsanlage", Dissertation, TU-Wien, Institut für Verfahrenstechnik, Umwelttechnik und technische
Biowissenschaften derzeit eingereicht:
Gmeinbauer J., Ramakrishnan C , Reichhold A.; "Prediction of FCC Product Distributions by Means of Feed Parameters", für OIL-GAS-European Magazine Reichhold A., Ramakrishnan C , Wlaschitz P.; "Alternative FCC-Feedstocks:
Recycling of Used Frying Oil", für Fluidization XI conference, Sorrento, Italy (2004)
SONSTIGE KURSE UND WEITERBILDUNG:
• 5. Juli 2001 Seminar: H.D.I. - Die Persönlichkeit im Team, BWK Wien
• 5.-8. Mai 2002 Teilnahme an der „7th International Conference on Circulating Fluidized Beds" in Kanada, Präsentation der obigen Publikation
• 3.-4. Juni 2002 Seminar: Biotechnologie der Antibiotika, Biochemie GmbH, Kundl
SONSTIGE KENNTNISSE UND INTERESSEN:
• Computer (Windows, Linux, Office, CAD, VBA, Corel, Adobe, etc.)
• Buchhaltung
• Maschinschreiben - Golf
• Reisen
Mödling, 28.03.2004