DOI: 10.3303/CET24109030 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Paper Received: 15 December 2023; Revised: 1 March 2024; Accepted: 5 April 2024 
Please cite this article as: Leal Silva J.F., Maciel Filho R., 2024, Techno-economic Analysis and Life Cycle Assessment of Renewable 
Acetaldehyde from Sugarcane Ethanol, Chemical Engineering Transactions, 109, 175-180  DOI:10.3303/CET24109030 
  

 CHEMICAL ENGINEERING TRANSACTIONS  
 

VOL. 109, 2024 

A publication of 

 

The Italian Association 
of Chemical Engineering 
Online at www.cetjournal.it 

Guest Editors: Leonardo Tognotti, Rubens Maciel Filho, Viatcheslav Kafarov 

Copyright © 2024, AIDIC Servizi S.r.l. 

ISBN 979-12-81206-09-0; ISSN 2283-9216 

Techno-economic Analysis and Life Cycle Assessment of 

Renewable Acetaldehyde from Sugarcane Ethanol 

Jean Felipe Leal Silva, Rubens Maciel Filho 

School of Chemical Engineering, University of Campinas, Av. Albert Einstein, 500, Campinas, SP, 13083-852, Brazil 

jeanf@unicamp.br 

Acetaldehyde has been historically synthesized from ethanol via oxidation. However, since the 1960s, the cost 

of feedstock and conversion process has gradually driven manufacturers to prefer the liquid-phase oxidation of 

ethylene. However, the aggravation of the effects of the climate crisis demands a shift from fossil feedstocks to 

renewable feedstocks to reduce society’s CO2 footprint. Moreover, sugarcane ethanol production is a more 

mature process nowadays, delivering a low-cost renewable chemical. Bearing all this in mind, this work analyzes 

the viability of the production of acetaldehyde via oxidation of sugarcane ethanol. The key idea is to integrate 

the process into a sugarcane biorefinery to take advantage of the surplus energy of optimized distilleries to 

provide renewable energy for acetaldehyde production. The oxidation process of ethanol to acetaldehyde in the 

gas phase was simulated using literature data. Process data for the remaining sections of the sugarcane 

biorefinery were based on literature data as well. Based on equipment sizing and processing capacity, a cash 

flow analysis was performed to determine the best operating conditions for acetaldehyde production via ethanol 

oxidation. Results have shown that the conversion of ethanol to acetaldehyde using this process is competitive 

and can increase the earnings of the biorefinery. A life cycle assessment was performed as well to compare the 

carbon intensity of acetaldehyde produced from ethanol to the carbon intensity of acetaldehyde produced via 

direct oxidation of ethylene, showing a reduction of 85%. Results demonstrate that the oxidation of ethanol 

represents a renewable alternative with economic potential when integrated into a sugarcane biorefinery. 

1. Introduction 

Acetaldehyde (ethanal) is an important chemical intermediate with applications in chemicals, perfumes, 

pharmaceuticals, and plastics. It can be used in the production of acetic acid, acetone, ethyl acetate, acetic 

anhydride, pyridines, and alkylamines (Hagemeyer, 2014). Since the 1960s, acetaldehyde has been mostly 

produced via liquid-phase oxidation of ethylene in the presence of a metal catalyst (Jira, 2009), in the Wacker 

process, while there are still some commercial plants working with partial oxidation of ethanol and hydration of 

acetylene. Despite the reliability of mature technology, the Wacker process has drawbacks such as high 

consumption of energy and the use of a non-renewable raw material — ethylene, produced via steam cracking 

of petroleum fractions or natural gas liquids (Moulijn et al., 2013). In the face of the current climate crisis, 

alternative processes to replace non-renewable chemicals with green chemicals must be developed (Ncube et 

al., 2023). 

Ethanol oxidation was the preferred route to produce acetaldehyde before the development of the Wacker 

process, which took over as the preferred process option by 1968 in the United States (Hagemeyer, 2014). 

During this time, the Wacker process became more economically attractive because of feedstock costs. 

However, since then, ethanol production from corn and sugarcane has grown significantly, and costs reduced 

(Cantarella et al., 2023), which might make this raw material attractive again. Moreover, bearing in mind the 

effects of the climate crisis, it is important to move away from non-renewable sources by developing and 

improving chemical processes that are based on green chemicals and renewable feedstocks, such as ethanol. 

In this context, the catalytic conversion of ethanol to acetaldehyde has been studied using Fe and Mo catalysts 

(Maciel Filho et al., 1996), and the recovery process has been studied as well in terms of process design and 

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energy demand (Leal Silva and Maciel Filho, 2024). Nevertheless, it is still needed to identify the economic 

competitiveness of the process and determine potential bottlenecks. 

One of the potential tools to ensure the economic success of green chemicals is their integration into large 

biorefineries (Lopes et al., 2021). As the process for production of renewable acetaldehyde demands ethanol 

and energy (heat and electricity), integrating this process into a sugarcane biorefinery with surplus electricity 

production could enable cost-competitive production of renewable acetaldehyde (Solarte-Toro and Cardona 

Alzate, 2021). Therefore, this study presents a techno-economic analysis of the production of acetaldehyde 

from sugarcane. Twelve scenarios of different process conditions for the conversion of ethanol were integrated 

into a conventional, optimized sugarcane biorefinery via process simulation. These scenarios were compared 

to a standard sugarcane biorefinery producing ethanol and electricity in terms of economic indicators to assess 

the feasibility of acetaldehyde production from sugarcane. Results of mass and energy balance were also used 

to estimate the carbon footprint of renewable acetaldehyde, which was compared to the standard value for the 

fossil-based chemical.  

2. Methodology 

Figure 1 shows the proposed biorefinery layout to produce acetaldehyde. The biorefinery processes were 

simulated in Aspen Plus 8.6 (Aspen Tech, Inc., Bedford, USA). Ethanol production from sugarcane juice and 

burning of sugarcane bagasse to produce steam and electricity were simulated based on process conditions 

reported in the literature for the optimized process currently implemented in modern sugarcane processing 

facilities in Brazil (Dias et al., 2016), assuming a processing capacity of 4 million t of sugarcane per year, 

operating 200 d/y (during sugarcane harvest). The base scenario, called ET-0, represents the case in which the 

biorefinery produces only ethanol and electricity — all sugarcane bagasse is consumed by the biomass boiler.  

 

 

Figure 1: Proposed biorefinery layout to produce acetaldehyde from sugarcane ethanol. 

The ethanol oxidation step to produce acetaldehyde was based on the process design provided in the literature 

as well (Leal Silva and Maciel Filho, 2024). In this process, ethanol was vaporized and mixed with air with molar 

ratios of O2 to ethanol of 3.2, 6.1, and 9.0. The mixture was then passed through a fixed bed reactor, simulated 

by an RStoic model, with conversion based on experimental results (Maciel Filho et al., 1996). Recovery of 

acetaldehyde was a cumbersome task because it was mixed with nitrogen (from air). In this case, to avoid the 

use of organic solvents, the gas stream was compressed and passed through a gas absorber to recover the 

acetaldehyde and unconverted ethanol. In this absorber, the gas stream was contacted with a cold water stream 

(5 °C) whose flow rate was calculated so that the concentration of volatile organic compounds in the gas was 

reduced to 20 mg C/Nm3, compatible with European legislation (European Union, 1999). 

For each of the three above-indicated reaction conditions, four absorber pressures were evaluated because the 

working pressure affects the water flow rate demanded to recover the acetaldehyde. This resulted in a total of 

twelve scenarios of different process conditions. Scenarios were named A3-1, A3-2, A3-3, and A3-4 for the 

molar ratio of 3.2 and each possible working pressure for the absorber (3.1 bar, 5.0 bar, 8.0 bar, and 13 bar 

corresponds to -1, -2, -3, and -4, respectively), and similar naming was used for the other molar ratios (A6-x for 

the molar ratio of 6.1 and A9-x for the molar ratio of 9.0). The aqueous solution containing acetaldehyde was 

then distilled to recover the acetaldehyde as the product of the process. From the remaining aqueous solution, 

ethanol was recovered and recycled to the oxidation reactor and water was recovered and recycled to the gas 

absorber. Electricity for the compressors and heating and cooling utilities for the other unit operations were 

drawn from the biorefinery utilities section, represented by the biomass boiler in Figure 1. 

The capital cost of equipment for the conversion of ethanol to acetaldehyde was estimated based on the results 

of mass and energy balances provided by the process simulator and the module costing technique (Turton et 

al., 2018). The reactor was dimensioned as a scaled-up multi-tubular reactor based on previous results (Maciel 

176



Filho et al., 1996). Distillation columns were initially designed based on short-cut methods, and the provided 

results were then used in the rigorous RadFrac model of Aspen Plus, which can be used to estimate column 

dimensions. The absorber was modeled using the RadFrac model as well, assuming a random packing of Pall 

rings of 25 mm. Heat exchangers were dimensioned based on heat exchange area, which was calculated using 

the heat duty, the mean temperature difference, and the overall heat transfer coefficient calculated using Aspen 

Exchanger Design and Rating 8.4. 

Based on these results, the bare module cost (CBM) for equipment at base conditions was calculated using Eq. 

(1). In this equation, B1 and B2 are constants that are particular to each process equipment, available in tables 

in the literature (Turton et al., 2018). FP is the pressure factor, which increases the demand for construction 

material as the operating pressure increases, and it is calculated using Eq. (2) and constants C1, C2, and C3, 

particular to each equipment type, with values available in the literature (Turton et al., 2018). FM is a constant 

that is related to the material of construction. In this case, as acetaldehyde is not corrosive, a combination of 

carbon steel and stainless steel was chosen depending on the service and temperature for which each unit 

operation was intended. The value of this constant depends on the equipment type, and these values are 

available in the literature as well (Turton et al., 2018). Cp
0 is the base purchase cost of equipment at standard 

conditions, calculated using Eq. (3). Cp
0 is a function of constants K1, K2, and K3, particular to equipment type 

with values available in the literature (Turton et al., 2018), and A, which is the capacity or sizing parameter for 

each equipment (e.g. heat transfer area for heat exchangers). The sum of these costs yields the capital 

expenditure (CapEx) of the acetaldehyde plant.  

𝐶𝐵𝑀 = (𝐵1 + 𝐵2𝐹𝑃𝐹𝑀)𝐶𝑝
0 (1) 

𝑙𝑜𝑔10(𝐹𝑃) = 𝐶1 + 𝐶2 𝑙𝑜𝑔10(𝑃) + 𝐶3(𝑙𝑜𝑔10(𝑃))2   (2) 

log10(𝐶𝑝
0) = 𝐾1 + 𝐾2 log10(𝐴) + 𝐾3(log10(𝐴))2  (3) 

The CapEx of the sugarcane ethanol plant and the utility section (cogeneration of heat and power based on 

biomass and cooling water section) of the biorefinery were estimated based on results from the literature (Dias 

et al., 2016; Leal Silva et al., 2022). Operational expenditure (OpEx) included cost with sugarcane ($21.0/t), 

straw ($28.9/t), additional inputs for ethanol production ($0.066/Lethanol), wastewater treatment 

($0.222/m³wastewater), labor cost (average monthly wage of $1280), maintenance (3% of CapEx), and taxes (34% 

of net income according to Brazilian law) (Brazilian Ministry of Economy, 2023; Dias et al., 2016; Leal Silva et 

al., 2018; Souza et al., 2022; Ulrich and Vasudevan, 2006). Revenue was obtained by selling ethanol (in 

scenario ET-0, $810/t), acetaldehyde (in all other scenarios, $1010/t), and electricity (in all scenarios, 

$48.1/MWh). Linear depreciation was assumed, and a project lifetime of 30 years was chosen, with a catalyst 

service time of 10 years. Economic parameters suitable for the sugarcane sector in Brazil were based on 

previous literature (Dias et al., 2016). The results of CapEx and OpEx were then combined in a cash flow 

analysis to calculate the internal rate of return of each biorefinery scenario. 

Life cycle assessment (LCA) was performed for the scenario producing acetaldehyde with the best internal rate 

of return. The study considered a cradle-to-gate attributional LCA with the system boundary defined in Figure 

2. The goal was to determine the carbon footprint of 1 kg of acetaldehyde as the functional unit. Emissions were 

allocated based on the revenues of the biorefinery because electricity is a product as well and it is incompatible 

with the functional unit of mass. Feedstock was assumed to be sugarcane produced in the state of São Paulo, 

Brazil, according to data available in the Ecoinvent database 3.8 (Ecoinvent Association, 2021, Zurich, 

Switzerland). Additional process inputs were included as well (Dias et al., 2016; Souza et al., 2022). The 

assessment was conducted using the ReCiPe 2016 midpoint hierarchist method implemented on openLCA 

1.11.0 (GreenDelta GmbH, 2022, Berlin, Germany). 

 

 

Figure 2: System boundary considered in the life cycle assessment of the biorefinery. 

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3. Results and Discussion 

Figure 3a shows the composition of the CapEx of each biorefinery scenario. Cogeneration of heat and power is 

the biggest contributor to the total CapEx of the biorefinery because no other use was given to the sugarcane 

bagasse except for burning to produce steam and electricity. As such, it represents 48% to 49% of the total 

CapEx of each scenario producing acetaldehyde. Electricity is a biorefinery product of low value-added. In this 

case, condensing turbines are employed to maximize electricity production, which is then sold to the grid, and 

these turbines are costlier than backpressure turbines that could be used otherwise if no excess steam was 

produced. The acetaldehyde process has a large electricity demand because of the compressors employed in 

the recovery process: the electricity demand of the total process (sugarcane extraction, ethanol production, and 

acetaldehyde production) increases sharply depending on recovery conditions, from +57% to +154% compared 

to the base scenario (0-ET). The integration into the biorefinery means that electricity is produced onsite at a 

reduced cost, which is fundamental to ensuring the economic feasibility of the process. 

 

 

Figure 3: a) CapEx composition of each biorefinery scenario, including the base case ET-0, and b) CapEx 

composition of the acetaldehyde plant. 

The acetaldehyde plant is fairly inexpensive compared to the total CapEx of the biorefinery, ranging from 8% to 

10%. The major contributor to the CapEx of the acetaldehyde plant is the absorption step, mainly because of 

the compressors required to deliver the gas stream at the pressure required by the absorber. Figure 3b shows 

the composition of the CapEx of the acetaldehyde plant, and it is possible to observe that the share of the 

absorption step increases as the amount of excess air being used increases (higher O2 to ethanol molar ratio, 

scenarios A3-x vs. A6-x vs. A9-x) or as the operating pressure of the absorber increases for each given O2 to 

ethanol molar ratio (variations -1, -2, -3, or -4 for each A3-x, A6-x, or A9-x). Additionally, as the excess gas 

increases, conversion increases, and less ethanol is recycled. Therefore, the capital cost associated with 

ethanol distillation decreases as the ratio of O2 to ethanol increases. Also, as the pressure increases, the amount 

of water required in the gas absorber decreases, which decreases the capital cost associated with water 

recycling inside the acetaldehyde plant. Therefore, in the graph of Figure 3b, the capital cost of the distillation 

section of the acetaldehyde plant gradually decreases from left to right. 

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Figure 4a shows the calculated internal rate of return of all scenarios producing acetaldehyde. The results 

indicate that the best scenario is the one with an O2 to ethanol molar ratio of 6.1 whose acetaldehyde is 

recovered on a gas absorber working at 5.0 bar (scenario A6-2). In this scenario, single pass conversion is only 

62.78%. However, the additional recycling of ethanol is more economically attractive than working with a larger 

excess of O2 or a greater pressure in the gas absorber, both factors that increase expenses related to gas 

compression. Scenarios using an O2 to ethanol molar ratio of 9.0 present comparable results as the ones using 

an O2 to ethanol molar ratio of 6.1, with the pressure of 5.0 bar being the best one. In the case of an O2 to 

ethanol molar ratio of 3.2, the optimal pressure is not clear, but the trend of the results indicates that if low 

pressures are required to work in this process, a lower excess of air might be desired. Nevertheless, the internal 

rate of return for a higher excess of O2 is preferable. 

 

 

Figure 4: a) internal rate of return of the biorefinery for each O2 to ethanol molar ratio (3.2, 6.1, and 9.0) for the 

four gas absorber pressures and b) sensitivity analysis of the CapEx and prices of acetaldehyde and electricity 

for scenario A6-2 (O2 to ethanol molar ratio of 6.1 and gas absorber pressure of 5 bar). 

Figure 4b shows the sensitivity analysis for the CapEx and prices of electricity and acetaldehyde. Changes of 

±20% in electricity price have a minimal impact on the internal rate of return because, in general, electricity has 

low participation in the revenues, ranging from 10.1% (in scenario A9-4) to 11.5% (in scenario A3-1). In contrast, 

changes of ±20% in acetaldehyde price can make the internal rate of return range from 15.9% to 26.1%. 

Therefore, the process can be deemed economically viable because, despite fluctuations in acetaldehyde price 

of ±20%, the internal rate of return of the biorefinery is, in general, greater than a minimum acceptable rate of 

return of 12%, which is generally required for sugarcane biorefineries in Brazil (Dias et al., 2016). Sensitivity 

analysis was performed on the CapEx related to the cogeneration of heat and power, cooling utilities, and the 

acetaldehyde plant, which are the primary sources of uncertainty in capital cost estimation since the capital cost 

of the other sections was based on data validated with industrial data (Dias et al., 2016). According to these 

results, errors of ±20% in the CapEx of these sections, which represent 57% to 58% of the total CapEx, can 

yield an internal rate of return in the range of 19.4% to 23.5%. For comparison, the internal rate of return of 

scenario ET-0, producing only ethanol and electricity, was 20.0%, thus indicating that this additional option for 

the sugarcane industry is competitive with ethanol. 

The calculated carbon footprint of acetaldehyde produced via the Wacker process, according to the Ecoinvent 

database, is 1.5437 kgCO2e/kg, whereas the carbon footprint of the acetaldehyde produced from sugarcane 

ethanol via the process of scenario A6-2 is 0.2247 kgCO2e/kg. This 85% reduction is attributed to the avoided 

use of fossil fuels in the processing of raw materials into acetaldehyde, which was accomplished by using 

sugarcane bagasse to produce steam and electricity in the integrated biorefinery. As this is a cradle-to-gate 

LCA, this analysis does not consider the final use of acetaldehyde. In the case of renewable acetaldehyde, if 

this molecule were to be used in the synthesis of fuels, the greenhouse gases produced during its combustion 

would be considered biogenic carbon, thus not contributing to the total emissions of the fuel. 

4. Conclusion 

This work analyzed the production of acetaldehyde from sugarcane via oxidation of ethanol. A total of twelve 

scenarios were analyzed, consisting of a combination of different reaction and recovery conditions. Capital 

179



expenditures of each biorefinery scenario were calculated, indicating that the use of higher pressure in the gas 

absorber had a significant impact on the capital cost of this section of the plant. Considering the integrated 

biorefinery, the scenario with the best internal rate of return was the one using an O2 to ethanol molar ratio of 

6.1 combined with a gas absorber working at 5.0 bar. This was the combined result of reduced energy spending 

with power to compress gas and reduced energy spending in the distillation of acetaldehyde, unconverted 

ethanol, and water to be recycled to the gas absorber. These conditions led to an internal rate of return of 21.2%, 

greater than the base scenario in which the biorefinery produces ethanol and electricity (20.0%). Life cycle 

assessment was used to determine the carbon footprint of acetaldehyde produced from sugarcane, which based 

on the best process conditions was 0.2247 kgCO2e/kg. This value is 85% lower than the emissions related to 

the production of acetaldehyde via the Wacker process. Overall, these results indicate that the production of 

acetaldehyde from sugarcane is a techno-economically feasible process, with the potential to replace fossil-

derived acetaldehyde produced via the Wacker process. 

Acknowledgments 

The authors acknowledge the support from FAPESP (the Sao Paulo Research Foundation, #2022/16379-8 and 

#2015/20630-4) and the Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - Brasil (CAPES) - 

Finance Code 001. 

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