Philip Lutze

Sustainable Process Synthesis-Intensification

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A systematic synthesis and design methodology to achieve process intensification in (bio) chemical processes

Abstract Process intensification (PI) has the potential to improve existing processes or create new process options, which are needed in order to produce products using more sustainable methods. In principle, an enormous number of process options can be generated but where and how the process should be intensified for the biggest improvement is difficult to identify. In this paper the development of a systematic computer aided model-based synthesis and design methodology incorporating PI is presented. In order to manage the complexities involved, the methodology employs a decomposition-based solution approach. Starting from an analysis of existing processes, the methodology generates a set of process options and reduces their number through several screening steps until from the remaining options, the optimal is found. The application of the methodology is highlighted through a case study involving the chemo-enzymatic synthesis of N-acetyl- d -neuraminic acid (Neu5Ac).

Integrated processing for the separation of biobutanol. Part A: experimental investigation and process modelling

Abstract n-Butanol is an important bulk chemical and a promising potential fuel additive. An alternative way to the chemical production of biobutanol from crude oil is the fermentation of biomass. However, the main drawback of this process is the toxicity of n-butanol towards the microorganisms resulting in a limited productivity. Additionally, high purification costs occur due to an energy-intensive distillation step which is used, up to now, as purification technology for the recovery of n-butanol. Therefore, alternative separation processes are discussed in this study. Extraction and pervaporation are two unit operations with high potential to overcome this problem. Because of their tuneable properties, the use of ionic liquids as extraction solvents for n-butanol recovery is a promising option; however, their economic potential is not obvious because of the relatively high costs. On the basis of those two unit operations, different potential processes to separate biobutanol from water are modelled using experimental data. Cost estimations result in purification costs of €0.230 kg-1 to €0.296 kg-1 n-butanol, which accounts for 20%–27% of the n-butanol market price in 2012.

Modeling, Simulation and Experimental Investigation of a Reactive Hybrid Process for the Production of Dimethyl Carbonate

Abstract Process intensification has been identified as a main tool to achieve higher efficiencies leading to a more sustainable production. Especially hybrid as well as reactive separations allow for increased separation efficiency at the same time reducing the energy consumption. Integrating reactive and hybrid separations within one process may create even larger positive synergy effects. However, by this integration several process configurations exist and the identification of the best process operation remains unsolved. Hence, a process analysis tool has been developed to identify the most promising intensified process configuration based on simple calculations and secondly, to identify the influence of the process parameters on the target variables. To underline the potential of this tool, the equilibrium-limited transesterification of propylene carbonate forming dimethyl carbonate is investigated. For this system, a reactive hybrid process integrating reactive distillation and vapor permeation is designed in this work.

PSE Tools for Process Intensification

Abstract Process intensification is considered to be one important tool to meet the requirements for more efficient and sustainable processing. Even though many different intensified technologies have been developed, only some of them have been implemented in industry yet. One of the reasons is that process synthesis and design of intensified processes, benchmarking between different intensified technologies or targeted intensification beyond currently existing solution is complex and challenging. Addressing such complexity and offering systematic solution procedures is the strength of process systems engineering. Therefore, an overview of some of the recently developed methods and tools for process design and synthesis to achieve process intensification acting at different scales of the process is given.

Integrated processing for the separation of biobutanol. Part B: model-based process analysis

Abstract The biochemical production of n-butanol by fermentation is an interesting option for the sustainable production of a chemical that can be used as a fuel additive or solvent. However, n-butanol is toxic towards the production organisms, resulting in low concentrations of biobutanol in the aqueous fermentation broth. Therefore, conventional purification by distillation is very energy intensive. Extraction with ionic liquids and pervaporation as alternative separation technologies are two promising options for energy-efficient n-butanol recovery. These processes are analysed on detailed economics, including the influence of the uncertainty of the used model parameters and the sensitivity of the production costs to model parameters and design variables. It is shown that the costs for n-butanol purification by means of distillation are strongly dependent on the costs for thermal energy. For extractive recovery, the solubility of the extraction solvent in the raffinate is one of the main cost drivers as it affects the solvent loss. The costs of the pervaporation-based recovery mainly depend on the price for the membranes and are strongly dependent on the permeate fluxes. For all processes, the feed concentration has a noteworthy effect on the total downstream costs. This study allows not only an analysis of existing technologies but also helps to guide future research.

Reactive distillation for production of n-butyl acrylate from bio-based raw materials

Abstract Due to the scarcity of oil in the future, alternative resources and production pathways for the production of chemicals need to be identified. To allow for an economic production of these chemicals, the use of innovative equipment and methods has to be investigated to intensify the processes. Reaction distillation integrates separation by distillation and reaction into one unit and is already known to be a promising concept to improve process performance, leading to more sustainable processes. However, the design of reactive distillation processes using bio-based raw materials is difficult because the wide impurity profile of the reactants may lead to a large number of additional reactions and thermodynamic non-idealties. Hence, within this work, a 4-step methodology for the design of a reactive distillation column processing bio-based resources is presented. In this study, the focus is on the impact of impurities, resulting from the use of bio-based raw material. Based on these results, the product purity in presence of the impurities is analysed and operational and design changes to overcome identified product purity limitations will be presented.

Experimental and theoretical investigation of multistage extraction of 1,3‐propanediol using the extraction system phosphate/1‐butyl‐3‐methylimidazolium trifluoromethanesulfonate/water

The separation of 1,3‐propanediol from fermentation broth is a challenging and energy‐demanding step using conventional unit operations. One alternative process is the use of an aqueous two‐phase system incorporating ionic liquids to use synergy effects of both technologies. Within this manuscript, the technical feasibility of the extraction of 1,3‐propanediol using the aqueous two‐phase system phosphate (salt)/1‐butyl‐3‐methylimidazolium trifluoromethanesulfonate (ionic liquid)/water in a continuously operated process in pilot‐scale is presented. The extraction was performed in a multistage mixer–settler unit and successfully modeled with an equilibrium‐stage model and correlations to describe the liquid–liquid equilibrium of the salt/ionic liquid/water two‐phase system. The developed and validated model was used for a further investigation of the influence of different process parameters in the determined operating window. Theses parameters include the number of stages, the phase ratio, the pH, and the mass fraction of the involved components. The results prove that the phosphate and 1‐butyl‐3‐methylimidazolium trifluoromethanesulfonate mass fraction, the phase ratio, and the number of stages have a considerable influence on the recovery of 1,3‐propanediol, whereas the pH value has only a smaller impact. Those results can be used for optimization of the system as well as for targeting future research within this area.

Phenomena-based Process Synthesis and Design to achieve Process Intensification

Abstract Process intensification (PI) has the potential to improve existing processes, necessary to achieve a more sustainable production. PI can be achieved at different levels. That is, the unit operations, functional and/or phenomena level. The highest impact is expected by looking at processes at the lowest level of aggregation: phenomena. Therefore, in this paper, a phenomena-based synthesis/design methodology is presented. Using this methodology, a systematic identification of necessary and desirable (integrated) phenomena as well as generation and screening of phenomena-based flowsheet options are made using a decomposition based solution approach. The developed methodology is highlighted through a case study involving the production of isopropyl-acetate.

Distillation in Bioprocessing

Abstract To produce biological products within the pharmaceutical and food industries, as well as to establish more sustainable production within the chemical and specialty chemical industries, biotechnological processes play an important role. Biotechnology is an interdisciplinary research field combining biology (microbiology, molecular biology, genetics, bioinformatics), chemistry (biochemistry, classical chemistry) and engineering (process engineering, apparatus engineering). Biotechnology is dealing with the development of biocatalysis (enzymes to carry out a reaction that perform inside or outside of a cell) and biocatalytic reaction routes as well as the design of bioproducts. It is accompanied by research focusing on the development of biobased processes using biobased raw materials based on nonbiocatalytic processing steps. Even though the main focus of both is often within the reaction, downstream processing within biotechnological processes plays a crucial role for the development of efficient and economic processes. However, the challenges and bottlenecks for separation/purification within biotechnological processes vary dramatically depending on the product. Besides biopharmaceuticals/biomedicals (red biotechnology), plants (green biotechnology) and petrochemical products are replaced by biochemicals through the development of processes of industrial biotechnology (white biotechnology) or biobased processing. In this chapter, the contribution of classic distillation, hybrid separations as well as new distillation-based technologies such as reactive distillation are highlighted in the different application fields within bioprocesses. Additionally, the outlook for new distillation technologies, such as Higee distillation, are discussed, along with challenges regarding design/synthesis tools necessary for the development of economic and sustainable bioprocesses that will enable reliable and quick implementation into large-scale production.