Production Of Propylene Glycol Research Articles

An alternative to methanol recovery from ternary mixture: Replacing extractive with reactive distillation for maximizing economical potential and resource recovery

This paper investigates the recovery of methanol from the propylene oxide (PO)/methanol/water mixture using reactive distillation (RD). The mixture presents a challenge due to the azeotrope formation between PO and methanol. To overcome this challenge, three RD scenarios, designated as Case 1, Case 2, and Case 3, are proposed. The primary principle underlying these cases is leveraging a reaction between PO and water, resulting in the production of propylene glycol (PG). This reaction consumes PO and thus eliminates the PO-methanol azeotrope, and reduces reboiler duty via the release of reaction heat. Case 1 utilizes one reactive distillation column (RDC) and one conventional distillation column (CDC) to recover methanol while reducing a quarter of the water content via the PO-water reaction. High purity methanol is obtained in the RDC distillate, while high purity PG is collected at the bottom of the CDC. Likewise, Case 2 follows the same approach as Case 1, with an additional PO stream to halve the water content. On the other hand, Case 3 employs a single RDC with a greater additional PO stream to react with all water content in the mixture, yielding high purity methanol at the distillate and PG at the bottom. These cases are simulated using Aspen Plus software, and their designs are optimized to minimize the total annual cost (TAC). The results are compared to a base case, represented by the side-stream extractive distillation (SSED) method. Cases 1, 2, and 3 demonstrate TAC reductions of 7.8 %, 27.7 %, and 60 %, respectively, compared to the base case. Additionally, the PG produced by the PO-water reaction presents opportunities for generating extra profit of 6.356 × 107 $ a−1, 7.248 × 107 $ a−1, and 8.98 × 107 $ a−1 in Cases 1, 2, and 3, respectively. Given the financial benefits observed in each case, these configurations may serve as attractive alternative methods for methanol recovery from the PO/methanol/water mixture.

Design and Mechanical Analysis of a Continuous Stirred Tank Reactor (CSTR) for the Optimum Operation and Production of Propylene Glycol from Propylene Oxide Hydrolysis

This study aimed to optimize the production of propylene glycol by designing a continuous stirred tank reactor (CSTR) and analyzing its thickness. The research involved developing a reaction kinetic scheme and mass and energy balance models to determine key reactor functional parameters and account for temperature effects. Simulation results for a yearly production of 400,000 tons of propylene glycol showed a reactor volume, height, diameter, spacetime, space velocity, and heat generation per unit volume at maximum conversion and operating temperature of values 62.08 m3, 6.81 m, 3.41 m, 2,608.70 s, 0.00038 s-1, and -1.30 J/m3s, respectively. The relationship between fractional conversion, operating temperature, and reactor functional parameters was presented, while the mechanical design of both the CSTR column and stirrer was considered. The study recommended a thickness specification of 23 mm for an ellipsoidal-shaped column head made from stainless steel material type 304 due to its ability to withstand operating conditions. CSTR design and its thickness analysis are crucial for the optimum production of propylene glycol because they ensure the proper mixing of reactants and prevent heat loss during the exothermic reaction. This leads to increased reaction efficiency, higher yields, and improved product quality. Results showed that proper CSTR design and thickness analysis are essential for optimal propylene glycol production for domestic and industrial applications.

Selective Electrified Propylene-to-Propylene Glycol Oxidation on Activated Rh-Doped Pd.

Renewable-energy-powered electrosynthesis has the potential to contribute to decarbonizing the production of propylene glycol, a chemical that is used currently in the manufacture of polyesters and antifreeze and has a high carbon intensity. Unfortunately, to date, the electrooxidation of propylene under ambient conditions has suffered from a wide product distribution, leading to a low faradic efficiency toward the desired propylene glycol. We undertook mechanistic investigations and found that the reconstruction of Pd to PdO occurs, followed by hydroxide formation under anodic bias. The formation of this metastable hydroxide layer arrests the progressive dissolution of Pd in a locally acidic environment, increases the activity, and steers the reaction pathway toward propylene glycol. Rh-doped Pd further improves propylene glycol selectivity. Density functional theory (DFT) suggests that the Rh dopant lowers the energy associated with the production of the final intermediate in propylene glycol formation and renders the desorption step spontaneous, a concept consistent with experimental studies. We report a 75% faradic efficiency toward propylene glycol maintained over 100 h of operation.

Biobased propylene glycol production in a sugarcane biorefinery through lactic acid, glycerol, or sorbitol: A techno-economic and environmental evaluation of intermediates and downstream processing methods

Propylene glycol (PG) is a versatile chemical which can be produced by direct fermentation of sugars or through intermediates like lactic acid (LA), glycerol and sorbitol. Few studies have examined producing PG from different intermediates in terms of economic feasibility. In this study, seven process scenarios were assessed in a biorefinery annexed to an existing sugar mill. Aspen simulations were developed for each scenario as the basis for mass and energy balances, techno-economic, and environmental evaluations. Scenario 1 (LA intermediate) had the lowest minimum selling price (MSP) of 1991 US$t−1 and greenhouse gas (GHG) emissions of 1.24 kgCO2/kgPG which was the best intermediate investigated. Scenario 2a-2d (glycerol intermediate) was used to offer insights on the economic benefits of different design changes to the process. Scenario 2a investigates the use of reactive distillation as opposed to normal distillation in the other scenarios. Scenario 2c and 2d offer insights on the purchasing of green hydrogen as an alternative to producing onsite and effect of increased hydrogen ratios respectively. The MSP for the scenarios ranged from 2121–2863 US$.t−1 and GHG emissions of 0.8–2.2 kgCO2/kgPG. Scenario 3 (sorbitol intermediate) had the poorest performance with an MSP of 2751 US$t−1 and GHG emissions of 2.22 kgCO2/kgPG. Scenario 4 (combined first and second-generation feed) had an MSP of 2065 US$t−1 and 1.04 kgCO2/kgPG for GHG.

Implementation and Analysis of a Digital Twin for Propylene Glycol Production: Dynamic Simulation and Process Statistical Control

Purpose: Development of a dynamic simulation and analysis system for Propylene Glycol production through the hydrolysis of Propylene Oxide, utilizing market-available tools including a Digital Twin developed in the Unisim/Honeywell Simulation integrated to the PI System AVEVA/OSIsoft. This system aims to provide a realistic industrial environment for subsequent analysis and statical quality control. Theoretical framework: The manufacturing of Propylene Glycol involves complex reactive systems that require precise control and optimization. The integration of advanced simulation tools and statistical control charts, such as Shewhart Control Charts, is pivotal in monitoring and enhancing the quality of the process. This approach addresses the need for efficient process management in the chemical industry. Method/design/approach: The project employs a decoupled simulation structure, where the reactive system and the statistical control system operate simultaneously, exchanging information through the PI System supervisory software (AVEVA/OSIsoft) and a Python programming environment. The implementation of Shewhart Control Charts within the simulation provides real-time process quality monitoring. Results and conclusion: The outcomes demonstrate the feasibility of using a combination of software tools for daily industrial event simulation, as well as for training and acclimatizing engineers and operators. The analysis of statistical control charts allows for the detection of special cause variations, offering valuable insights for efficient process intervention, thereby enhancing the quality of both the process and the final product. Research implications: This study contributes to a deeper understanding of reactive systems in chemical engineering and the effective integration of simulation and statistical process control techniques. Originality/value: The development of a simulation framework that combines Digital Twin technology with statistical process control for the efficient and reliable production of Propylene Glycol.

Simulation Of The Optimum Operating Conditions For A Propylene Glycol Production Unit Using Aspen Hysys Software

Commercially, propylene glycol is produced by the direct hydrolysis of propylene oxide with water. This first-order, irreversible, exothermic reaction is performed in a glass-lined Continuous Stirred Tank Reactor (CSTR). In this study, the initiation of a CSTR was modelled from first principles and simulated using Aspen Hysys 3.2 to obtain concentration and temperature profiles. It is often very important how these profiles approximate the steady-state values. For example, when approaching a steady state the temperature may rise too high and this leads to degradation of the reactant or product, or the altitude may be unacceptable for safe operation. If either condition occurs, the system will exceed its practical stability limit. The practical stability limit represents the temperature above which it is undesirable to operate due to undesirable side reactions or equipment damage. Therefore, the best-operating conditions were obtained in terms of the flow rate of the raw material and the temperature of the reactor at 345 Kgmol/h and 82.2 °C on straight. The production of propylene glycol in the presence of an acid catalyst in an isothermal tank reactor is presented using advanced process simulation software. The effect of temperature was also calculated using the principle of energy balance on the reactor. The reactor operates optimally at a fractional conversion of 0.995 to obtain optimal values for the most important variables/parameters [reactor volume 7.92 m3, reactor length 2.83 m, reactor diameter 1.89 m, and amount of heat required for cooling per unit volume of the reactor 1205 kw].

ORLEN Poludnie plant makes propylene glycol production more sustainable based on BASF technology

ORLEN Poludnie plant makes propylene glycol production more sustainable based on BASF technology

Equivalence between Minimum Entropy and Exergy Applied to Continuous Stirred‐Tank Reactors

AbstractMinimum entropy and exergy concepts were applied to continuous stirred‐tank reactors (CSTRs) to assess their effectiveness as analytical and optimization tools as well as to clarify some existing controversy regarding their practical applications. The second law of thermodynamics was used to establish in detail the concepts themselves or in the formulation of the exergy balance. Relevant information was extracted from both, in addition to which differences between them were revealed. By applying a commercial software package to the production of propylene glycol, the results of theoretical analysis and simulation showed that such concepts produced equivalent effects when applied to CSTRs and, due to the operating conditions, exergy proved to be independent of the so‐called dead state. Therefore, it is concluded that both procedures lead to equivalent optimization strategies when applied to CSTRs and depending on the objectives, but the use of minimum entropy may be more advantageous for some approaches, as it does not depend on the dead state.

Stochastic economic evaluation of different production pathways for renewable propylene glycol production via catalytic hydrogenolysis of glycerol

The impact of the hydrogen production method on the economic feasibility and environmental friendliness of propylene glycol production from glycerol hydrogenolysis is explored.

Liquid-liquid extraction of lactic acid using non-toxic solvents

Lactic acid is a carboxylic acid that is important due to its applications in various industries like pharmaceutical, cosmetics, chemicals, and food industries. It can be used for the production of ethanol, acrylic polymers, and propylene glycol. However, lactic acid extraction from downstream is a major challenge, hence an attempt was made to recover the acid by liquid-liquid extraction from the aqueous stream. In this paper, the extraction of lactic acid from the water stream was done using rice bran, sesame, and mustard oil. The experimental data were defined in different parameters viz. distribution coefficient (K D ) and extraction efficiency (η) at 298.15 1 K. The distribution coefficient and extraction efficiency were found as follows: Sesame oil (0.28, 22.37%) > Rice Bran oil (0.19, 16.66%) > Mustard oil (0.13, 12.16%).

Hydrogenolysis of Glycerol to Propylene Glycol: Energy, Tech-Economic, and Environmental Studies.

Hydrogenolysis of glycerol to propylene glycol represents one of the most promising technologies for biomass conversion to chemicals. However, conventional hydrogenolysis processes are often carried out under harsh H2 pressures and temperatures, leading to intensive energy demands, fast catalyst deactivation, and potential safety risks during H2 handling. Catalytic transfer hydrogenolysis (CTH) displays high energy and atom efficiency. We have studied a series novel solid catalysts for CTH of glycerol. In this work, detailed studies have been conducted on energy optimization, tech-economic analysis, and environmental impact for both processes. The key finding is that relatively less energy demands and capital investment are required for CTH process. CO2 emission per production of propylene glycol is much lower in the case of transfer hydrogenolysis. The outcome of this study could provide useful information for process design and implementation of novel hydrogenolysis technologies for other energy and environmental applications.

Selective Hydrogenolysis of Biomass‐Derived Xylitol to Glycols: Reaction Network and Kinetics

AbstractThe conversion of bio‐based xylitol to ethylene glycol (EG) and propylene glycol (PG) was studied to replace the petrochemical production route and achieve a sustainable process. The reaction network for aqueous‐phase catalytic hydrogenolysis of xylitol over a supported Pt catalyst with Ca(OH)2 as promotor was identified and the reaction kinetics was determined. The effects of reaction conditions such as educt concentration, H2 pressure, and temperature were investigated. With the developed kinetic model, the composition of the product mixture regarding the desired products (EG, PG) and by‐products can be described. The maximum EG yield was achieved at high pressure and low temperature, while high pressure and temperature favored PG production.

Deviation propagation along a propylene glycol process using dynamic simulation: An innovative contribution to the risk evaluation

Nowadays, quantitative risk analysis is essential for safety process management. For this purpose, dynamic simulation is an efficient tool to predict the time evolution of process parameters during deviations from normal operating conditions. There is a real interest in knowing the system behavior during malfunctions for the design of safety barriers. As a matter of fact, the knowledge of the process dynamic behavior and the profiles of the operating parameters during a degraded mode permits to provide guidelines regarding the required safety barriers. Nevertheless, the description of the process dynamic behavior in case of failures remains a challenge. In this study, a methodology is proposed: it combines dynamic simulation with ASPEN PLUS DYNAMICS™ 9.0 software tool, lessons learnt from accidents and risk analysis. The primary focus of this paper is on risks occurring in distillation columns, unit operation involved in the case study. The case study concerns a continuous process of propylene glycol (C3H8O2) production. The synthesis unit involves three consecutive competitive reactions leading to the formation of by-products: di and tri glycols (C6H14O3 and C9H20O4 respectively). The process is composed of a CSTR reactor and two distillation columns in series (C1 and C2). Two deviation scenarios on C1 reboiler, chosen according lessons learnt from previous accidents, are simulated and the consequences on C1 and C2 operation analysed. Overpressure, flooding and weeping occurrence are put in evidence and quantified. This work provides a new perspective on risk quantification through the analysis of deviation propagation along a process involving several unit operations.

KAJIAN TEKNO EKONOMI PRODUKSI BAHAN PROPILENA GLIKOL BERBASIS BIOMASSA VIA HIDROGENOLISIS GLISEROL

Governmental policies that promote biofuels such as biodiesel have led to the generation a largeamounts of glycerol waste as a low-cost raw material. The purpose of this paper is to present a technoeconomic study on the production of biomass-based propylene glycol via glycerol hydrogenolysis,considering hydrogen feeds that partially or fully utilize renewable sources. For analysis andcalculation, computer simulations are carried out using the Aspen Hysys V11 simulator. The technoeconomic analysis is performed by modelling the propylene glycol synthesis process from glycerol,which is then used to calculate the facility capital cost and estimate operating costs to obtain an annualreturn on investment. Sensitivity analysis is also conducted for several parameters on a 36,000ton/year propylene glycol plant. The results showed the production cost was 0.76 USD/kg or 10,802IDR/kg when the hydrogen is generated from the natural gas steam-methane reforming (SMR)process. If the hydrogen is produced from the glycerol steam reforming process, which is fullyrenewable, the plant is not feasible, as indicated by a negative net present value (NPV).

Model based hazard identification: Process time accelerated by GPU redesigning approach

Process safety and risk assessment are major requirements in the industrial context and hazard identification is essential for ensuring safe design and operation of a process. Numerous automated software approaches to risk assessment have resulted in many improvements in human brainstorming techniques of conventional risk assessment. In terms of computing time as an important aspect of these automated tools, mathematical simulation of physical and chemical states of the process is most time consuming in comparison to results collection and evaluation. In this context, GPU parallel computing has many advantages which meet the demanding requirements on complex and precise process hazard analysis without the involvement of massive processing architectures. This paper presents an efficient low-cost way of significant acceleration of targeted prediction of incident consequences by dynamic simulation of process fault deviations in the context of safety analysis. The GPU based simulation computing algorithm acceleration has been demonstrated on a hazard and operability analysis of propylene glycol production carried out in a closed loop CSTR (continuous stirred tank reactor). In this application, HAZOP multi-parameter process deviations have been simulated 100 times faster than when using its CPU code version.

Propylene glycol from glycerol: Process evaluation and break-even price determination

Propylene glycol can be produced from the hydrogenolysis of glycerol. If hydrogen comes from a renewable source, the produced propylene glycol can be considered completely renewable. The objective of this work is to perform a technical and economic evaluation of a propylene glycol production process which uses glycerol as the main raw material. Two possibilities regarding the hydrogen source are explored: it may come from an external source or be produced locally. It is shown that the break-even price of the partially renewable propylene glycol is lower than the market price of propylene glycol, which indicates that this process is economically viable. It is also shown that the price of hydrogen produced via steam reforming is not competitive with its price if produced by other sources. Consequently, the fully renewable propylene glycol production process yields a lower profit, but it is still viable and depends on the market. • Propylene glycol production from glycerol is simulated in Aspen HYSYS®. • Hydrogen can also be produced from glycerol. • Is it economically viable to produce a fully renewable PG from glycerol? • Economic parameters were carefully selected from literature and market. • Technical aspects are rigorously considered.

Continuous production of propylene glycol (1,2-propanediol) by the hydrogenolysis of glycerol over a bi-functional Cu–Ru/MgO catalyst

A series of Cu–Ru/MgO catalysts were developed for the continuous production of propylene glycol from glycerol in a sectionally packed downflow tubular reactor in the vapor phase.

Heat Integration Analysis of Preliminary Plant Design of Glycerol Conversion into Propylene Glycol

The heat integration of the preliminary plant design of propylene glycol production from glycerol has been successfully conducted in order to obtain an efficient process due to the energy consumption. The optimum value of ∆Tmin is also determined in order to obtain the minimum total cost. The pinch technology is used as the tool for heat integration analysis conducted in this study which has been widely used for heat integration analysis. However, the use of pinch analysis for the heat integration of the production of propylene glycol from glycerol still doesn’t exist. In order to determine the optimum ∆Tmin, the ∆Tmin was varied and analyzed. Those ∆Tmin were 5, 10, 15, 20 and 25 K. The ∆Tmin dependence on heating duty, cooling duty, and the maximum energy recovery (MER) was also investigated. As the results, it was found that the heating duty, the cooling duty, and MER strongly depend on the value ∆Tmin. The heating duty and the cooling duty are directly proportional to the ∆Tmin. On the other hand, MER is inversely proportional to the ∆Tmin. The optimum ∆Tmin is estimated to be 15 K which gives $ 13530.480/year of utility cost and $ 89348.122/year of capital cost. The heat exchanger network of propylene production from glycerol is obtained at the optimum ∆Tmin.

Quantitative risk analysis using dynamic simulation: deviation propagation along propylene glycol process

Currently, there is a strong demand for quantitative risk analysis. There is a challenge in describing the process dynamic behaviour in case of failures. We suggest a methodology that combines dynamic simulation (with ASPEN PLUS DYNAMICSTM 9.0 tool), lessons learnt from accidents to identify the most likely deviations and risk matrices. In fact, there is a real interest in knowing the system behaviour during malfunctions for safety analyses. For this purpose, dynamic simulation is an efficient tool to predict the time evolution of process parameters during deviations from normal operating conditions. Moreover, the knowledge of the process dynamic behaviour and the profiles of the operating parameters during a degraded mode permits adequate safety barrier recommendations. The case study concerns a continuous process of propylene glycol (C3H8O2) production. The synthesis reaction involves three consecutive competitive reactions leading to the formation of by-products: di and tri glycols (C6H14O3 and C9H20O4 respectively). The process is composed of a CSTR reactor and two distillation columns in series. The objective is to study the propagation of deviations along the process. This work provides a new perspective on risk quantification through the analysis of deviation propagation along a process involving cascade distillation columns.

Simulation-based Analysis of Propylene Glycol Production from Lactic Acid

Propylene glycol is an intermediate molecule with wide applications in the chemical industry. Its most successful renewable production technology is based on hydrogenolysis of glycerol, subproduct of the biodiesel industry, which has been commercially produced since the early 2010s. The biodiesel market, however, is highly dependent on government incentives and raises the fuel versus food debate. Other renewable raw materials that can be obtained from lignocellulosic sources, such as cellulose and lactic acid, have been studied for propylene glycol production through similar technology but focusing on catalyst development. In that regard, this work developed a conceptual design and simulation using Aspen Plus® for propylene glycol production from lactic acid. To assess its potential as feedstock, mass and energy balances were compared with those reported in the literature for glycerol-based propylene glycol. The results demonstrate that there is room for improvement towards a competitive lactic-acid based biorefinery, especially in terms of energy consumption.