Original Papers
The Valve Opening Effect on Pilot Plant Scale Distillation of Cinnamon (Cinnamomum burmanii) Leaf Oil Characteristic
2026 Volume 27 Issue 3 Pages 25-32
Details
2026 Volume 27 Issue 3 Pages 25-32
Cinnamon leaf oil was obtained by laboratory-scale steam distillation, however, industrial application requires scale-up, since steam flow rate controlled by valve opening influenced characteristics. This study investigates steam valve opening effects on pilot-scale cinnamon leaf oil characteristics. Yield, volatile compound and physicochemical properties were evaluated across ¼, ½, and ¾ valve opening. The results of this study showed a significant difference at 5% significancy level in the specific gravity and refractive index values which the wider valve opening of the steam pipe results in higher specific gravity and refractive index. This was related to the oxygenated compound found in the wider valve opening of the steam pipe. Still, there was no significant difference between the samples in yield, solubility in 70% alcohol, and viscosity. The volatile compounds at the ¼-valve opening of the steam pipe were more diverse compared to the two other samples. The volatile compounds area of this study showed that a wider valve opening in the steam pipe reduces the Area of volatile compounds. Narrower valve openings significantly increase specific gravity and refractive index without affecting yield, alcohol solubility, or viscosity, also produce more diverse volatile compound compositions and higher peak areas.
Essential oils are plant-derived substances obtained through various extraction techniques, including hydro diffusion, solvent extraction, distillation, and mechanical pressing. Distillation is a widely used extraction method for producing essential oils. This method used a water-based technique ― either the liquid phase, the steam phase, or a combination of both ― to extract volatile compounds from plant materials. Water, as the carrier phase in the distillation method, interacts with the plant matrix, facilitating the release of volatile compounds. The volatile compounds carried by the water in the steam phase are then condensed into a liquid form. The yield of this process is a biphasic system named the distillate. The distillate contains essential oil and water as a carrier system, which can be separated by its difference in polarity and specific gravity [1].
According to the Directorate General of Estate Crops, Ministry of Agriculture, Indonesia, cinnamon bark is the part of cinnamon that is exported extensively. In 2023, cinnamon bark production reached 54,748 tons, increasing to 55,204 tons in 2024, with a productivity rate of 1,444 kg/ha in 2023 and 1,464 kg/ha in 2024. This significant increase in both production and productivity of cinnamon bark is boosting the export potential of this commodity. In 2023, the data indicated that the total export of cinnamon bark reached 23,000 tons. The export destinations include major cities worldwide, such as the United States, the Netherlands, Vietnam, Malaysia, Thailand, France, Brazil, Jerman, Sweden, India and several other countries Whole bark cinnamon and cinnamon powder derived from the bark were the most widely exported [2]. In contrast, cinnamon leaves are often discarded and become wasteful. The production of waste is prompting consideration of producing cinnamon leaf oil to reduce potential waste.
Cinnamon leaf oil (CLO) is an essential oil produced from cinnamon leaf with various chemical compounds. The different extraction methods used to obtain CLO may affect the chemical compound profile, even when produced from the same plant [3]. Water steam distillation method at the laboratory scale with air-dry pretreatment resulted in 0.1016 % (v/w) of yield; 0.91-0.95 g/mL of specific gravity; 0.0023 N・s/m2 of viscosity; 1.48-1.51 of refractive index; and 1:0.8:1.5 of 70% alcohol solubility [4].
The scale-up approach to evaluate the efficiency of laboratory methods before application at an industrial scale is called a pilot plant [5]. The purpose of scale-up is to ensure that laboratory procedures are compatible with industrial processes and to apply optimization parameters established at the laboratory scale. In the food industry, a pilot plant is essential for assessing factors such as product quality, raw material requirements, energy consumption, and other operational aspects [6].
Steam distillation is one of the most widely used methods for producing essential oils, especially at the pilot plant scale. This method uses water in the gas phase as an extracting agent rather than organic solvents. Based on the characteristics of water and oil that are immiscible with each other, the separation of these is easy. In addition, steam distillation at the pilot plant scale was economically feasible, making this approach suitable for scale-up research [7]. Several factors can influence the productivity of steam distillation, including valve opening. The valve is usually installed in the pipeline connecting the boiler, which serves as the steam generator, to the distillation chamber. This partition function regulates both the steam flow rate and the quantity of steam [8].
In addition to those factors, the capacity of the distillation chamber used in the system also affects distillation efficiency. Utilizing the distillation chamber’s maximum capacity in steam distillation may yield inefficient results. This case directly uses the optimal ratio between the raw material load and the chamber’s maximum capacity [9]. However, the distillation efficiency depends on the amount of sample; overloading the material can hinder steam flow. This may prevent the steam from carrying on the volatile compounds. Otherwise, using too little material in the chamber may allow the steam to pass through easily, resulting in a too-short contact time between the plant matrix and the steam, which decreases efficiency. The maximum capacity for optimal steam distillation is up to 75% [10]. This study aims to know the effect of valve opening (one-fourth (¼), one-half (½), and three-fourths (¾)) on cinnamon leaf oil (Cinnamomum burmannii) characteristics (yield, specific gravity, 70% alcohol solubility, viscosity, refractive index, and volatile compounds content) at 50% capacity of pilot plant scale distillation.
The main material used in this research was cinnamon leaves collected from Bubukan, Girimarto, Wonogiri, Central Java, Indonesia. Other materials used in this research were distilled water, Natrium sulfate anhydrous (Merck), UHP Hydrogen, Ethanol 70% (Merck).
2.2 Methods 2.2.1 SamplesCinnamon leaves were collected from Bubukan, Girimarto, Wonogiri, Central Java, Indonesia. The leaves were manually sorted to select only those of optimal quality and to remove any attached branches. Selection criteria included full-sized leaves free from holes, physical damage, or defects. Over-dried and over-aged leaves were discarded. The selected cinnamon leaves were then air-dried to a moisture content of 10-12% [10]. After drying, the leaves were chopped to reduce particle size. The chopping was performed using a chopper equipped with a 30 × 30 cm2 inlet, a 26.5 × 15 cm2 outlet, and 36 blades, with a capacity of 11 kg of dry leaves per hour. This process produced chopped leaves measuring approximately 4-6 cm in length referring to previous research as the best pre-treatment for size reduction [4].
2.2.2 Cinnamon Leaf Oil DistillationPilot-plant-scale steam distillation was used in this research. Distillation used 50% of the capacity and took 6 hours. This research used valve openings of ¼ (one-fourth), ½ (one-half), and ¾ (three-fourths)―one set of pilot-scale steam distillation plants. The specification of the distillation set was distillation chamber made from stainless steel 201 with diameter of 120 cm (equipped with stop valve and handle), continuous fire tube boiler made from stainless steel 201 with diameter of 30 cm (equipped with manometer (0-200 kPa), thermometer (0-130°C)), safety valve, inlet and outlet, spiral condenser made from stainless steel ornament (pipe size: 0.5 inch (1.5 × 2 m)), UNP (U-Normal Profile) steel portable frame with roller wheels. The distillation set is shown in Fig. 1.
Pilot-plant steam distillation set.
CLO was separated from water using both physical and chemical methods. The physical method used a separating funnel and monyl fabric, with gravity settling [11]. The chemical method used 1% (w/w) Natrium sulfate anhydrous as the water absorbent [12].
2.2.4 Cinnamon Leaf Oil CharacterizationThe CLO obtained from the distillation process was then characterized for its yield [13] and its volatile components using a Gas Chromatography-Mass Spectrometry (GC-MS) method with a Shimadzu QP2010S instrument with this following operation condition: the sample volume was injected at 0.1 μL. the pressure of the GC-MS was 100 kPa, the column temperature was set at 80°C and the injection temperature was set at 280°C. The flowrate was set at 3 mL/min in the split injector. The oven temperature was raised to 270°C at 10°C/min. The detector temperature was set at 250°C. The hydrogen flowrate was set at 40 mL/min [9]. The other characteristics, such as specific gravity, 70% alcohol solubility, viscosity, and refractive index, were determined successively with ISO 279:1998, ISO 875:1999, ISO 3104:2020, and ISO 280:1998.
2.2.5 Data AnalysisThis research used a randomized design with one factor (valve opening variation). Repetition was applied twice in both treatments and the analysis. All data were analyzed statistically using a one-way ANOVA. If there was a difference, Duncan Multiple Range Test (DMRT) was applied at a significance of 0.05.
This research produced three variations of CLO. The product is shown in Fig. 2. There was a slight difference in color in the different samples of variation. This different color may affect the characteristics of those variations. The results of CLO characterization in this research are shown in Fig. 3. This result showed that valve opening significantly affects specific gravity and refractive index, but not yield, 70% alcohol solubility, or viscosity. Based on this research, the various volatile compounds were detected by Gas Chromatography-Mass Spectrometry (GC-MS) analysis. This finding can guide valve-opening selection to produce the CLO based on needs.
CLO obtained from pilot-plant steam distillation with (A) one-fourth (¼)-valve opening, (B) half (½)-valve opening and, (C) three fouth (¾)-valve opening.
Pilot Plant Steam Distillation CLO Characteristics.
The CLO yield was calculated by the ratio of oil weight in grams after refining as final product with the weight of the dry material used as the initial raw material. This calculation was presented as percentage that represents the proportion of raw material recovered after processing and shows how much losses during processing. The CLO yield results were 6.3×10-2% to 8.9×10-2% (v/w).. This result showed that the pilot-plant-scale steam distillation yield was higher than the laboratory-scale yield, by 5×10-2% (v/w) [10]. Although the pilot plant design yielded a higher yield than the laboratory-scale design, no significant difference in valve-opening variation was observed. In this study, the one-fourth (F1) valve-opening treatment produced the highest yield, 8.9×10-2% (v/w).
The valve opening may affect the steam flow rate linearly: the wider the opening, the higher the flow rate [14]. The steam flow rate affected the steam pressure in the distillation chamber. The wider valve opening with a higher steam flow rate led to a decrease in pressure in the distillation chamber, as predicted by Bernoulli’s law [15]. This occurrence affected the yield of the distillation result. This study found that valve opening did not significantly affect yield, but yield decreased with wider valve opening. In the pilot plant distillation, the higher capacity than the laboratory scale affected the final volume of essential oil produced by the system, even though the yield percent at different valve openings showed no significant difference.
The decrease in yield value when a wider valve opening is used may be affected by the pressure and flow rate in the distillation system. The high flow rate in the system reduces pressure, thereby decreasing the yield percent [16]. The wider valve opening increases the flow rate [17]. Furthermore, the high steam flow rate in the system resulted in a short contact time between the steam, as the carrier medium, and the material in the chamber―this is consistent with the retention time of the steam as a carrier medium in the system. The high steam flow rate requires a shorter time to reach the essential oil boiling point, which results in a shorter contact time and, consequently, a shorter retention time. This short retention time between the carrier medium and the material affected the diffusion of volatile compounds from the plant, thereby reducing the yield of essential oil [13]. In line with those facts, the yield decrease might be due to the CLO’s constituents. High pressure can accelerate the degradation of constituents, forming unwanted compounds, and may denature volatile compounds due to high temperature and pressure [18].
3.2 Volatile CompoundsGC-MS method used to identify the volatile compounds in the CLO composition. l-linalool and cineole were detected as typical compounds with dominant emergence. Those compounds were found in all treatments, with varying relative amounts. l-linalool and cineole were detected as typical compounds of cinnamon leaf oil from Cinnamomum burmannii species [4, 10]. The GC-MS results showed that the wider valve opening resulted in lower area accumulation. This showed that a three-fourths valve opening (F3) produces the lowest volatile compound composition. This result was linear with the yield obtained in this research, which decreased as the valve opening increased, indicating that more oil with a higher concentration of volatile compounds was extracted.
The narrower valve opening was associated with a greater accumulation of volatile compounds. This case was indicated by its larger total peak area in the GC-MS analysis. The various volatile compounds were detected in the narrowest valve opening in this research. This case is associated with the longer retention time of the system in the narrower valve opening, in line with the lower steam flow rate and higher steam applied in the system [13].
These various volatile compounds are components of the CLO, arranged by oxygenated terpenes and hydrocarbon terpenes. The longer retention time facilitated the diffusion of oxygenated compounds [18]. It was linear with this research, in which more compounds were detected at the lowest valve opening. Furthermore, the typical volatile compounds found in this research were L-linalool and cineole. This finding was consistent with the research before [4, 10].
3.3 Physicochemical CharacteristicsThe CLO specific gravity increased linearly with the valve opening used in this study. The three-fourths valve opening (F3) resulted in a CLO specific gravity that differed significantly from those of the other two samples. This difference may occur due to the differences in the components of compounds in the samples. The wider valve opening results in a CLO with a higher relative Area of oxygenated compounds, thereby affecting the specific gravity. The oxygenated compounds have a higher specific gravity [19], which aligns with our findings. Oxygenated compounds have longer chains and more double bonds, which are associated with higher specific gravity [20].
These oxygenated compounds components are also related to the refractive index value of the CLO. In this research, the refractive index of the CLO was affected significantly by the valve opening. The refractive index of the CLO increased as the valve opening increased. This was related to the double bond in the oxygenated compounds, which could bend light, resulting in a CLO with a higher refractive index [12].
Relative area of pilot-plant steam distillation CLO compound type.
| Compounds name | Molecular Formula |
Peak Area | ||
|---|---|---|---|---|
| Valve Opening ¼ (F1) | Valve Opening ½ (F2) | Valve Opening ¾ (F3) | ||
| Terpene compounds | ||||
| P-Cymene | C10H14 | 2,316,749 | 275,295 | 162,083 |
| α-thujene | C10H16 | - | - | 14,450 |
| α-inene | C10H16 | 6,595,585 | 2,022,650 | 742,089 |
| Camphene | C10H16 | 371,971 | 89,686 | 26,250 |
| Sabinene | C10H16 | - | 82,475 | - |
| β-pinen | C10H16 | 10,016,724 | 1,680,893 | 757,494 |
| β-myrcene | C10H16 | 2,458,017 | 339,080 | 109,616 |
| β-phellandrene | C10H16 | 940,447 | 83,933 | 101,400 |
| α-phellandrene | C10H16 | 815,874 | 184,977 | 59,229 |
| Carene | C10H16 | 94,806 | 32,439 | - |
| Ocimene | C10H16 | 1,524,458 | 35,526 | 10,132 |
| Terpinene | C10H16 | 694,839 | 40,322 | 32,752 |
| Neo-alloocimene | C10H16 | 24,766 | - | - |
| Bicycloelemene | C15H24 | 144,334 | - | - |
| Cubebene | C15H24 | 146,601 | 23,464 | - |
| Limonene | C10H16 | - | - | 19,038 |
| Copaene | C15H24 | 1,869,757 | 471,105 | 731,465 |
| Bourbonene | C15H24 | 224,088 | 47,090 | 62,373 |
| Elemene | C15H24 | 235,130 | 52,887 | 68,152 |
| α-himachalene | C15H24 | 88,575 | - | - |
| Zingiberene | C15H24 | 41,351 | - | - |
| Caryophyllene Fcc | C15H24 | 1,697,832 | 412,187 | 609,425 |
| Germacrene | C15H24 | 725,196 | 193,808 | 258,338 |
| Bergamotene | C15H24 | 153,445 | 60,146 | 83,944 |
| Aromadendrene | C15H24 | 937,113 | 238,304 | 92,871 |
| Humulene | C15H24 | 674,718 | 155,592 | 223,163 |
| Cadinene | C15H24 | 1,446,137 | 311,327 | 535,452 |
| Bicyclogermacrene | C15H24 | 730,392 | 201,570 | 304,253 |
| Bisabolene/Limene | C15H24 | 195,137 | - | - |
| Thujopsen | C15H24 | 44,413 | - | - |
| Kaurene | C20H32 | 789,952 | 298,213 | 357,556 |
| Neoalloocimene | C10H16 | - | - | 261,885 |
| Oxygenated compounds | ||||
| Cineole | C10H18O | 22,856,912 | 5,064,685 | 3,065,973 |
| Sabinene Hydrate | C10H18O | 35,448 | - | - |
| Linalool Oxide | C10H18O2 | 709,700 | 59,102 | 66,464 |
| l-Linalool | C10H18O | 49,216,595 | 14,490,053 | 12,578,984 |
| Fenchyl Alcohol | C10H18O | 10,421 | - | - |
| Pinocarveol/Pinyl Alcohol | C10H16O | 119,461 | 47,522 | 30,883 |
| Pinocarvone | C10H16O | 36,274 | 8,620 | - |
| Borneol | C10H18O | 623,695 | 142,173 | 143,052 |
| Terpineol | C10H18O | 3,101,299 | 950,644 | 251,247 |
| Linalool Propinoate | C13H22O2 | 1,594,483 | - | 847,640 |
| Citral | C10H16O | 47,669 | - | - |
| Linalyl Acetate | C12H20O2 | 41,874 | 16,826 | 12,952 |
| Citral | C10H16O | 32,714 | - | - |
| Nerol | C10H18O | 89,948 | - | - |
| Geraniol | C10H18O | 195,399 | - | - |
| Bornyl Acetate | C12H20O2 | 626,176 | 170,478 | 149,276 |
| Ionone | C13H20O | 31,705 | - | - |
| Nerolidol | C15H26O | 717,803 | 203,652 | 127,470 |
| Spathulenol | C15H24O | 417,400 | 131,409 | 224,985 |
| Epoxycaryophyllene | C15H24O | 333,140 | 96,753 | 188,322 |
| α-Cadinol | C15H26O | 75,377 | - | 42,827 |
| Benzyl Benzoate | C14H12O2 | 8,998,853 | 1,548,410 | 2,959,927 |
| Hexahydropseudoionone | C13H26O | 16,325 | - | - |
| Benzyl Salicylate | C14H12O3 | 58,871 | - | - |
| Phthalic Acid | C8H6O4 | 1,331,589 | 267,090 | 355,268 |
| Farnesol | C15H24O | 58,487 | - | - |
| Other compounds | ||||
| Methylcyclohexane | C7H14 | 8,790 | - | - |
| Toluene | C7H8 | 8,762 | - | - |
| Cycloisosativene | C15H24 | 45,855 | - | - |
| 8-heptadecene | C17H34 | 10,071 | - | - |
| Mintsulfide | C15H24S | 19,258 | - | - |
| Geranyl Mercaptan | C10H18S | 97,728 | - | - |
| Calamenene | C15H22 | - | - | 37,989 |
| Total Peak Area | 127,566,476 | 30,530,379 | 26,706,660 | |
The solubility in 70% alcohol and viscosity of the CLO was also analyzed in this research, but both characteristics showed non-significant results as the valve opening increased. The non-significant result may be due to the similar carbon chain in all samples. Even though there was no significant difference, there was a slight difference when the different valve opening was applied. The wider valve opening results in a CLO that requires less alcohol to dissolve. This is because the oxygenated compounds were more readily soluble in alcohol due to the solvent’s polarity [7]. The viscosity value showed no significant difference, but even though there was none, the highest valve opening corresponded to the highest viscosity. The viscosity was measured in relation to the particle size in the sample [12], and this particle size was affected by the compounds present in the sample [7]. The higher long-chain carbon compound in the sample contributed to the sample’s higher viscosity [7]. In this research, the carbon chain in all the samples was similar, which may have contributed to the non-significant result for the viscosity value.
In conclusion, the highest CLO yield obtained in the research was from pilot-plant steam distillation with one-fourth of the steam valve open. This condition produced the most varied volatile compounds compared with other conditions. This also affected the specific gravity and refractive index, resulting in lower values. However, in this research, the solubility of CLO in 70% alcohol and the viscosity did not show significant differences. It may have been conducted with a similar amount of carbon chain in the sample, as detected by its volatile compounds. Also, pressure changes during the distillation process may also affect the characteristics of the CLO so that the pressure gradient during the distillation process is still possible to be explored further.
This research was financially supported by the research group project of Non-APBN UNS No: 371/UN27.22/PT.01.03/2025 from Universitas Sebelas Maret (UNS), Indonesia.
