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                                                                       DOI: 10.3303/CET2189073 
 

 
 

 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 

 

 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 

Paper Received: 17 May 2021; Revised: 28 August 2021; Accepted: 3 November 2021 
Please cite this article as: Aziz F.H.A., Jusoh M., Zakaria Z.Y., 2021, Thermodynamic Analysis of Hydroxypropanone as Bio-Oil Model 
Compound to Light Hydrocarbons, Chemical Engineering Transactions, 89, 433-438  DOI:10.3303/CET2189073 

CHEMICAL ENGINEERING TRANSACTIONS 

VOL. 89, 2021 

A publication of 

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

Guest Editors: Jeng Shiun Lim, Nor Alafiza Yunus, Jiří Jaromír Klemeš 
Copyright © 2021, AIDIC Servizi S.r.l.
ISBN 978-88-95608-87-7; ISSN 2283-9216 

Thermodynamic Analysis of Hydroxypropanone as Bio-Oil 
Model Compound to Light Hydrocarbons  

Farra Hannis A. Aziz, Mazura Jusoh, Zaki Yamani Zakaria* 
School of Chemical Engineering, Universiti Teknologi Malaysia, 81310, Johor Bahru, Johor, Malaysia 
zakiyamani@utm.my 

Effort to seek sustainable renewable energy has been focused since the past decades in view of the
diminishing of petroleum and natural gas reserves. Bio-oil that can be obtained from biomass, has a complex, 
diverse, and large carbon range content in its current state, as opposed to gasoline's carbon range and lower 
hydrocarbon that can be used as fuel and intermediate products. Unfortunately, no specific thermodynamic
study was conducted on the transformation of bio-oil into light hydrocarbon. The long and complex carbon 
chain of bio-oil could be cracked into smaller carbon compounds in order to make use of its abundance
availability. Thermodynamic equilibrium analysis of bio-oil model compound to light hydrocarbons using overall 
Gibbs method of minimizing free energy was performed in this study. The composition of the equilibrium 
product for co-cracking of hydroxypropanone as model compound was determined in the following ranges: 
temperature, 300-1200 °C; HMR (hydroxypropanone/methanol ratio) and HER (hydroxypropanone/ethanol 
ratio), 1:12,1:6,1:3,1:1, 2:1 and pressure, 1 bar. Analysis of the feasible reactions found that main products
were hydrogen, carbon monoxide, carbon dioxide, while the formation of light hydrocarbons was not 
spontaneous. In comparison to other products, the amount of ethylene, methane, and ethane produced was 
very small. HMR 2:1, at temperature 1,200 °C and pressure 1 bar and HER 2:1, at 1,200 °C and pressure 1 
bar were the optimum conditions for ethylene production. 

1. Introduction
With growing global population, rising living standards globally and a finite supply of fossil fuels with negative
environmental consequences, the demand for clean and sustainable energy has rapidly risen. The main 
source of energy in the world so far is non-other than fossil fuels (Bezergianni and Dagonikou, 2015). 
Unfortunately, despite of its benefit, fossil fuels give countless bad effects towards the environment such as air 
pollution, water pollution, and others. Furthermore, the combustion and consumption of fossil fuels releases 
noxious greenhouse gases (Dayaratne at al., 2015). Because of that, researchers around the world enhance 
their research effort to seek for renewable energy alternatives. 
Out of numerous available alternative fuels, bio-oil has emerged and is deemed as highly potential renewable 
source of fuel because of its unique properties and it can be obtained from abundantly available biomass. For 
instance, catalytic biomass reaction can produce high-quality bio-oil by rapid pyrolysis process (Aziz and 
Makkawi, 2012). Bio-oil can be utilized as a source of energy for engines (Davidovits, 2013), as well as 
environmentally friendly binder and organic chemical resource (Dayaratne and Gunawardana, 2015). The 
usage of bio-oil from biomass could minimize the greenhouse effect and the occurrence of acid rain (Che et
al., 2019). Bio-oil is viscous, acidic and unstable due to the availability of its oxygenated components. On top 
of that, the oxygen level in bio-oil is also high. Bio-oil has a complicated chemical composition with mainly 
water, organics and traces of ash. Bio-oil applications are narrow due to the drawbacks of crude bio-oil, such 
as high humidity, acidity, high viscosity, and low heating value (García-Gómez et al., 2021). Organic acids,
ketones, aldehydes, esters, phenols, furans, and anhydrous sugars are among the 300 organically active
compounds found in bio-oil, which belongs to diverse functional groups. The low hydrogen-carbon ratio of 
crude bio-oil is an excellent molecule, which can act as a solvent for bio-oil. The greatest performance for 
cracking from a specific functional group in bio-oil can be observed in ketones. Hydroxypropanone is a 
common and dominant ketone in bio-oil that possesses five-membered rings and hydroxy groups. Ketones in 

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the form of hydroxypropanone derived from mango residue pyrolysis, emerged as the highest chemical yield 
in bio-oil (34 wt%) (Negahdar et al., 2016).  
As unique as it is, bio-oil existing state can be transformed into more valuable compounds by further 
processing and treatment. Among the possible methods are deoxygenation and catalytic cracking processes 
(Valle et al., 2021). The catalytic cracking technique increases the attraction of the olefin in the absence of 
high hydrogen pressure, and aromatic compounds found in bio-oil, in addition to increasing coke accumulation 
on the catalyst (Monoj Bardalai, 2015). There are some benefits to catalytic cracking over hydro processing 
since no hydrogen is needed, low operating cost due to atmospheric pressure application and temperatures 
are close to those used in bio-oil manufacturing. By removing oxygen from the reaction in the form of CO, 
CO2, and H2O, catalytic bio-oil cracking produces hydrocarbon-rich high-grade fuel. 
Catalytic cracking has been proven to transform specific compound (that is present in bio-oil) to more value 
added products. However, running various experimental testing for other feed and co-feed compound could be 
costly and time consuming. Hence, thermodynamic study is introduced and carried out to provide prediction 
on the formation of important products from the cracking of bio-oil model compounds. The model compounds 
can also be used to forecast different characteristics such as enthalpy or balance of phases for the reactions 
involved, state equations, coefficient of activity, empirical or system-specific specialties (Marques and 
Guirardello, 2018). The choice of models may depend on criteria like process species and compositions, 
temperature and pressure ranges, data availability, as well as other aspects. Some of the numerical models 
that are now considered computer models include computational fluid dynamic models, stochastic models, 
linear programming models, thermodynamic models, and chemical percolation models. All these models are 
designed for the purpose of simulating the physical flow activities, combustion, and other chemical reactions 
(Ma and Hanna, 1999). Various properties such as phase and enthalpy equilibrium can be predicted by using 
thermodynamics models. 
Recently, Liang and co-workers had performed thermodynamic analysis of acetic acid as bio-oil model 
compound conversion to light hydrocarbon, specifically ethylene and hydrogen (Liang et al., 2021). The 
outcome was very promising but more work still need to be done to investigate the performance of other 
model compounds for this thermodynamic study. Thermodynamics is an energy concept in which important 
element is the temperature as it is related to the average of molecular motions (Subsadsana et al., 2017). 
Thermodynamic analysis is necessary to identify the process's impact parameters on the reaction and the 
amount of the desired and unwanted products. As far as we are concern, thermodynamic analysis of 
hydroxypropanone as a model compound has not been investigated yet. As one of the highest content of bio-
oil, hydroxypropanone as a model compound should be investigated for its cracking conversion to light 
hydrocarbon and hydrogen. This will provide more understanding of the fundamental sciences required for the 
conversion of bio-oil to light hydrocarbon. The goal of this research is to determine the chemical equilibrium for 
the conversion of hydroxypropanone and methanol/ethanol as co-reactant for the production of light 
hydrocarbons, hydrogen and other co-products (CO2, H2O, CO and coke). The process was carried out by 
varying the parameters such as feed ratio and temperature by thermodynamic modelling. A list of possible 
reactions taking place and its respective Ln K versus temperature data is presented to comprehend the overall 
scenario. 

2. Methodology
HSC Chemistry version 11 was used to conduct the thermodynamic analysis. This program uses the Gibbs 
energy minimization approach for equilibrium calculations. The Gibbs program looks for phase compositions in 
which the system's Gibbs energy can be reduced to a minimum in a specified mass balance (a constraint 
minimization problem), constant pressure, and constant temperature. It is worthy to note that there are no 
input reaction equations. The species such as hydroxypropanone (CH3C(O)CH2OH) (g), hydroxypropanone 
with methanol (CH3OH) (g) and hydroxypropanone with ethanol (C2H5OH) (g) were considered as input 
species in this study. Methanol and ethanol are the co-reactant to provide source for oxygen and hydrogen. 
Hydrogen (H2) (g), methane (CH4) (g), carbon monoxide (CO)(g), carbon dioxide (CO2) (g), steam (H2O) (g), 
ethylene (C2H4) (g), and ethane (C2H6)(g), were the outlet gas products while carbon, aromatics, aliphatics, 
alcohols, esters, ketones, phenols and acids were other reaction products. This study did not include any 
other by product formation. 
The co-cracking for bio-oil production was based on the following parameters: temperatures, pressure and 
feed ratio (hydroxypropanone to methanol ratio (HMR) & hydroxypropanone to ethanol ratio (HER)). It's critical 
to look into the product distribution trends for bio-oil co-cracking in relation to temperature changes, pressure, 
the hydroxypropanone/methanol ratio, and the hydroxypropanone/ethanol ratio. The reaction products were 
supposed to have a thermodynamic balance in the reactor. The total intake of 2 kmoles was fixed for 
hydroxypropanones, hydroxypropanone with methanol and hydroxypropanone with ethanol. The working 

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temperature ranged from 300 °C to 1,200 °C, and the acetic acid to alcohol ratios were 1:12, 1:6, 1:3, 1:1, and 
2:1. Meanwhile, the operating pressure was set at 0.1, 1, 5, 10 and 50 bars. In all of the examples 
investigated, complete (100 %) conversion was observed, confirming the feasibility of the bio-oil co-cracking 
process and the positive output from the product. There was an acceptable error limit to the accuracy of the 
supplied data. 

3. Results and discussion
Table 1 tabulates the list of feasible reaction for the cracking of hydroxypropanone. 20 reactions were listed 
which were labelled R1 to R20. The carbon formation region, optimum conditions, and the process enthalpy 
were also determined. It is worthy to note that the main cracking occurred via R1 (Steam reforming of 
hydroxypropanone) followed by R2 and R3 which is basically the thermal decomposition reaction. Figure 1 
illustrates the temperature-dependent equilibrium constants for all reactions. A negative Gibbs free energy 
change (Gr) denotes a more realistic spontaneous reaction, according to thermodynamic principles. On the 
other hand, positive Gr thermodynamically limits the reaction. The equilibrium constant has an effect on the 
reaction's constant (K). Based on Figure 1, larger In K is defined as spontaneous reaction where the reactions 
are most likely to happen.  

Table 1 Feasible reaction in cracking of hydroxypropanone 

No  Reaction Type of reaction 
R1 C3H6O2 + 4H2O  3CO2 + 7H2 Steam Reforming of hydroxyacetone 
R2 C3H6O2  C3H4O + H2O Thermal decomposition 
R3 C3H6O2  CO2 + C2H6 Thermal decomposition 
R4 CH4  2H2 + C The production of coke is caused by the breakdown of 

CH4. 
R5 2CO  CO2 + C Coke formation by Boudouard reaction 
R6 CO + H2O  CO2 + H2 Water gas shift reaction (WGSR) 
R7 CH4 + 2H2O  CO2 + 4H2 Methane steam reforming 
R8 CH4 + H2O  CO + 3H2 Methane steam reforming 
R9 CH4 + CO2  2CO + 2H2 Methane dry reforming 
R10 CO + 3H2  CH4 + H2O Methanation reactions 
R11 CO2 + 4H2  CH4 + 2H2O Methanation reactions 
R12 2CO + 2H2  CO2 + CH4 Methanation reactions 
R13 C + 2H2  CH4 Hydrogenation or methanation reactions 
R14 CO + H2  C + H2O Carbon monoxide reduction reaction 
R15 CO2 + 2H2  CO + 2H2O Reverse water gas shift reaction (RWGSR) 
R16 CO2 + H2  CO + H2O Coke gasification 
R17 C + H2O  CO + H2 Coke gasification 
R18 CaO + CO2  CaCO3 Coke gasification 
R19 CaO + H2O  Ca(OH)2 Coke gasification 
R20 Ca(OH)2 + CO2  CaCO3 + H2O Coke gasification 

Based on Figure 1, it can be seen that reaction for coke gasification (R18, R19, and R20) are strongly 
spontaneous reactions at any temperature within the studied parameter. Reverse water gas shift reaction 
(RWGSR) (R15) is limited within the whole investigated temperature. Reactions R2, R3, R4, R7, R8, R9, R14 
and R17 are exothermic and likely to occur at lower temperature which is below than 600 °C due to its In K 
positive magnitude. These reactions are restricted at the high temperature (>600 °C) due to their negative ln K 
and equilibrium limitation.  
The large negative values of ln K for R1 indicate that these reactions are not feasible to occur except at very 
high temperatures. R5, R13 and R15 can only occur at high temperature (>700 °C). Below that temperature, 
the reaction will be affected by equilibrium limitations. Meanwhile for R6, this reaction is possible at above 900 
°C for formation carbon dioxide and hydrogen but these products also might be produced at lower temperature 
which is 700 °C at R5 and R12. Formation of methane from R10 and R11 will only occur at high temperature 
(700 °C).  
Figure 2 illustrates the effect of HMR and HER on the production of hydrogen through co-cracking of 
hydroxypropanone with varying temperatures set at a pressure of one bar. From Figure 2a, it can be identified 
that hydrogen production steadily increased with temperature, and hydrogen production started to be stagnant 
when it reached its peak after 1,000 °C. HMR 1:6 emerged as the best ratio for hydrogen production, just a bit 

435



lower than if hydroxypropanone was solely cracked. Figure 2d showed the influence of HER on the production 
of hydrogen at a 1 bar pressure at different process temperatures. Generally, hydrogen production increases 
steadily with the temperature and starts saturating and slightly increasing after the peak reaches its maximum. 
There are only slight differences between each HER ratios. The increase of hydrogen initially was mainly 
triggered from R1. Reactions R4, R7, R8, R9 and R17 although produces hydrogen, it was unlikely to take 
place at a lower temperature. However, upon comparing between the effect of methanol and ethanol co-
feeding, methanol co-feeding showed more attractive hydrogen production amount, with the same trend. 
Should the purpose of cracking is solely for hydrogen formation, hydroxypropanone cracking without co-
reactant is preferable. 

Figure 1: Co-cracking of hydroxypropanone involving equilibrium constants of reactions at atmospheric 
pressure. 

Figure 2b shows the trend of carbon monoxide moles that were produced from hydroxypropanone co-cracking 
with methanol at 1 bar pressure. It was observed that in all cases, the yield of carbon monoxide increased with 
temperature, similar to the trend of hydrogen formation. The carbon monoxide yields also increased with rising 
HMR at constant pressure. For example, carbon monoxide was low at lower HMR (HMR = 1:12) but as 
temperature increased, CO progressively increased as well. The unpredictable nature of high temperatures 
carbon monoxide can be linked to the balance between water gas shift reaction (WGSR)(R6) and R15 reverse 
water gas shift reaction (RWGSR). However, the low amount of carbon is related to the RWGSR reaction 
(R15).  
The methanation process is responsible for the low amount of carbon monoxide at high temperatures (600 °C) 
(R10 and R12) that actively consumes carbon monoxide. Figure 2e showed carbon monoxide moles formation 
with temperature when hydroxypropanone is co-cracked with ethanol (HER) at 1 bar pressure. The carbon 
monoxide output increased in all situations with temperature, showing similar trend to that of Figure 2b. 
Carbon monoxide production increases with HER at constant pressure. At lower HER (HER = 1:12) carbon 
monoxide was low but increased steadily with temperature. The spontaneity of carbon monoxide at high 
temperature can be related to the RWGSR reaction (R15). However, the least amount of carbon monoxide at 
temperature below 700 °C could be allocated to the R8, R9 and R17. 

-200

-150

-100

-50

0

50

100

300 400 500 600 700 800 900 1,000 1,100 1,200 1,300 1,400 1,500

In
 K

Temperature (℃)

R 1
R 2
R 3
R 4
R 5
R 6
R 7
R 8
R 9
R 10
R 11
R 12
R 13
R 14
R 15
R 16
R 17
R 18
R 19
R 20

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By referring Figure 2c, the number of ethylene, which is represent light hydrocarbon, is produced at varying 
temperatures and HMR at 1 bar pressure. From the observation of graph, moles of ethylene began to increase 
at temperature around 800 °C. Similarly, Figure 2f illustrates the number of ethylene moles production at 
higher temperatures and HER at 1 bar pressure. It can be discovered that moles of ethylene start to rise at 
800 °C and increasing at higher temperature around 1,200 °C. The HER did not have much effect on the 
production of ethylene. The 3 main reactions that initially triggers the formation of light hydrocarbon are R10, 
R11 and R13. Methane is formed in all these reactions and at higher temperature methane dissociate to 
unstable methyl radical. One unstable methyl radical combines with another methyl radical and forms ethane. 

 

Figure 2: Production yield: (a) H₂, (b) CO and (c) C₂H₄ for various HMR at 1 bar and (d) H₂, (e) CO and (f) 
C₂H₄ for various HER at 1 bar 

  e) 

  d) 

a)

  f) 

  b) 

c)

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Higher temperature induces ethane to release hydrogen and further form ethylene. These steps and the high 
temperature above 900 °C explain the reason ethylene formation commences at high temperature. 

4. Conclusion
In order to map the effect of HMR and HER on product dispersal patterns at pressure 1 bar and 300 °C to 
1,200 °C temperature within for ethylene yield, thermodynamic analysis of the hydroxypropanone co-cracking 
process was performed. To observe its impact on product yield, the effect of varying pressure was also carried 
out. Calculations of thermodynamic equilibrium show favorable yields for production of hydrogen and syngas, 
but not ethylene. The ideal situation for hydroxypropanone at temperature 1,200 °C and pressure at 1 bar with 
HMR 2:1, ethylene production can be increased utilizing methanol as a raw material. The optimum condition 
for maximizing the production of ethylene for hydroxypropapone with ethanol as raw material was 1,200 °C 
and 1 bar with HER 2:1. The production of light hydrocarbons in the presence of suitable catalysts can 
significantly improve by comparing the present study to numerous experimental works. Acceptable 
hydroxypropanone and selective catalysts are needed to promote light hydrocarbon production and to limit 
coking in optimal reaction conditions. 

Acknowledgement 

The authors would like to thank Universiti Teknologi Malaysia’s Collaborative Research Grant (4B485) and 
ministry of Higher Education Malaysia (MOHE) for the financial support through Fundamental Research Grant 
Scheme (FRGS/1/2020/TK0/UTM/02/97). 

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	Thermodynamic Analysis of Hydroxypropanone as Bio-Oil Model Compound to Light Hydrocarbons