André B. de Haan

Desulfurization and denitrogenation of gasoline and diesel fuels by means of ionic liquids

Ionic liquids can extract mono- and poly-aromatic sulfur and nitrogen compounds from gasoline and diesel and they perform better than conventional solvents. The extraction capacity of several ionic liquids for these heterocyclic compounds is determined and compared to the extraction capacity for aromatic hydrocarbons. Furthermore, the experimental results obtained are evaluated in view of the results reported in literature. It is shown that the ionic liquids investigated in this work are able to extract sulfur as well as nitrogen-containing aromatics in preference to aromatic hydrocarbons. Moreover, the ionic liquids [3-mebupy]N(CN)2, [4-mebupy]N(CN)2 and [bmim]C(CN)3 are superior to sulfolane, which has been used as a benchmark and also outperform the ionic liquids reported in literature so far. Finally, it has been shown that nitrogen-containing hetero-aromatics are significantly better extracted than sulfur-containing hetero-aromatics.

Optimal design of a multi-product biorefinery system

Abstract In this paper we propose a biorefinery optimization model that can be used to find the optimal processing route for the production of ethanol, butanol, succinic acid and blends of these chemicals with fossil fuel based gasoline. The approach unites transshipment models with a superstructure, resulting in a Mixed Integer Non-Linear Program (MINLP). We consider a specific problem based on a network of 72 processing steps (including different pretreatment steps, hydrolysis, fermentation, different separations and fuel blending steps) that can be used to process two different types of feedstock. Numerical results are presented for four different optimization objectives (maximize yield, minimize costs, minimize waste and minimum fixed cost), while evaluating different cases (single product and multi-product).

Cyano-containing ionic liquids for the extraction of aromatic hydrocarbons from an aromatic/aliphatic mixture

Ionic liquids can replace conventional solvents in aromatic/aliphatic extractions, if they have higher aromatic distribution coefficients and higher or similar aromatic/aliphatic selectivities. Also physical properties, such as density and viscosity, must be taken into account if a solvent is applied in an industrial extraction process. Cyano-containing ionic liquids have a lower density than the benchmark solvent sulfolane and a higher viscosity. Sulfolane is from a hydrodynamic point of view a better solvent than ionic liquids for the aromatic/aliphatic extraction. The most suitable ionic liquids for the extraction of aromatic hydrocarbons from a mixture of aromatic and aliphatic hydrocarbons are [bmim]C(CN)3, [3-mebupy]N(CN)2, [3-mebupy]C(CN)3, [3-mebupy]B(CN)4 and [mebupyrr]B(CN)4. They have factors of 1.2–2.3 higher mass-based distribution coefficients than sulfolane and a similar or higher, up to a factor of 1.9 higher, aromatic/aliphatic selectivity than sulfolane. The IL [3-mebupy]N(CN)2 is a better extractant for the separation of toluene from a mixture of toluene/n-heptane in a pilot plant Rotating Disc Contactor (RDC) than sulfolane.

Selection and evaluation of adsorbents for the removal of anionic surfactants from laundry rinsing water

Low-cost adsorbents were tested to remove anionic surfactants from laundry rinsing water to allow re-use of water. Adsorbents were selected corresponding to the different surfactant adsorption mechanisms. Equilibrium adsorption studies of linear alkyl benzene sulfonate (LAS) show that ionic interaction results in a high maximum adsorption capacity on positively charged adsorbents of 0.6-1.7 gLAS/g. Non-ionic interactions, such as hydrophobic interactions of LAS with non-ionic resins or activated carbons, result in a lower adsorption capacity of 0.02-0.6 gLAS/g. Negatively charged materials, such as cation exchange resins or bentonite clay, have negligible adsorption capacities for LAS. Similar results are obtained for alpha olefin sulfonate (AOS). Cost comparison of different adsorbents shows that an inorganic anion exchange material (layered double hydroxide) and activated carbons are the most cost-effective materials in terms of the amount of surfactant adsorbed per dollar worth of adsorbent.

Laboratory scale conceptual process development for the isolation of renewable glycolaldehyde from pyrolysis oil to produce fermentation feedstock

A laboratory-based separation sequence has been developed to produce an aqueous glycolaldehyde solution as fermentation feedstock. It consists of water extraction of pyrolysis oil, acid removal, water removal, octanol extraction, phenolic removal, back-extraction, and washing. The octanol-free aqueous glycolaldehyde solution contains approximately 4 wt% glycolaldehyde, which meets the requirement of fermentation feedstock.

Long term pilot plant experience on aromatics extraction with ionic liquids

Since 2004, we have been conducting pilot plant trials with various contactors and different ionic liquids for petrochemical model feeds as well as real refinery feeds. Our pilot plant contains a Rotating Disc Contactor with a height of 6 m and a diameter of 60 mm. Up to 100 kg of ionic liquid and 200 L of feed are applied in experiments. In this paper, the hydrodynamic and mass transfer performance of a rotating disc contactor has been characterized for toluene/n-heptane, a model FCC feed and a real LCCS refinery feed using 3-methyl-N-butyl-pyridinum dicyanamide ([3-mebupy]N(CN)2) as the ionic liquid. Experiments with the real LCCS feed demonstrated comparable extraction performance to the model FCC feed. Over the past 5 years, the same batches of the ionic liquid have been repeatedly regenerated by evaporation and reused. Our studies revealed that, although coloration occurs, the extraction performance of the ionic liquids has not changed even after several years of usage. After the real LCCS refinery feed experiments, validation with the toluene/n-heptane model feed confirmed unchanged extraction performance. Supplemental materials are available for this article. Go to the publishers online edition of Separation Science and Technology to view the free supplemental file.

Liquid-Liquid equilibrium study of phenol extraction with Cyanex 923

Abstract Although phenol extraction with Cyanex 923 has widely been studied, liquid-liquid equilibrium between phenol and undiluted Cyanex 923 has not been thoroughly investigated. Many factors influence the phenol extraction with undiluted Cyanex 923. Increasing the phenol concentration causes a water molecule replacement in the extractant by phenol molecules. Increasing the pH value above 12 decreases the phenol distribution coefficient KD by 99.9%. A temperature increase from 15°C to 65°C results in a KD decrease of 70%. With increasing salt content KD increases due to salting-out. Adding organic acids stabilizes phenol in the aqueous phase and obstructs the extraction.

Energy optimization in the process industries : unit commitment at systems level

In previous work, the unit commitment problem has been formulated as a non-convex MINLP, which is computationally expensive to solve. To circumvent this problem, we reformulate in this paper the problem as a convex MIQCP and derive the relevant constraints using propositional logic. We consider a specific problem based on a network of gas and oil fired power generators. Numerical results are presented using several methods (e.g. CPLEX for MIQCP, and DICOPT, SBB for MINLP). It is shown that proposed convex MIQCP reformulation can be solved much faster than previous non-convex models reported in the literature.

Ion Chromatography as a Novel Method to Quantify the Solubility of Pyridinium Ionic Liquids in Organic Solvents

A validated ion chromatographic method was developed and applied for the determination of the maximum solubility of pyridinium ionic liquids in several aromatic solvents. Elution was performed on a Metrosep C3-150 prototype column at 40°C with acetonitrile-water at a flow rate of 1.0 mL min(-1). Mixtures of pyridinium ionic liquids and aromatic solvents were diluted with acetonitrile and acetone on a 1:1:2 weight base before the analysis. The chromatographic time only took 20 min. The standard curves for both pyridinium ionic liquids ([4-mebupy]BF4 and [3-mebupy]N(CN)2) were linear (r(2) = 0.9980-0.9998) in all aromatic solvents (toluene, benzene, ethylbenzene and o-xylene) in the concentration range of 5.37-241 mg kg(-1). The intraday relative standard deviations (n = 3) for peak areas were 0.60-2.9%. Accuracy in the measurement of samples ranged from 98.5 to 105%. The limit of detection for both pyridinium ionic liquids in all solvents varied between 0.73 and 2.6 mg kg(-1). This assay has been successfully applied in the determination of the maximum solubilities of both pyridinium ionic liquids in several aromatic solvents. This method demonstrated that with increasing aromatic character and/or temperature the solubilities of both investigated pyridinium ILs in the aromatic solvents increase. This is primary caused by the nature of the anion.

Evaluation of configuration alternatives for multi-product polyester synthesis by reactive distillation

Abstract Reactive distillation (RD) combines reaction and separation in an integrated setup that is able to reduce the energy use, improve productivity and selectivity, and increase the efficiency. In previous work, we showed the design, modeling and experimental validation of a RD process for synthesis of unsaturated polyesters. The results of our previous work clearly demonstrated that reactive distillation is indeed a very promising alternative for the polyesters synthesis. This study explores the best suitable internals and various feed configurations of a reactive distillation process for unsaturated polyester synthesis. Multi-product simulations were performed to find the operational parameters for producing different grades of polyester in the same equipment. The product transition time during product changeover is determined for various configurations and product grades. The selection criteria for the best configuration are the minimum requirements of volume and energy to produce 100xa0ktpy polyesters. The results of the rigorous simulations carried out in Aspen Custom Modeler shows that the best configuration has the reactive stripping section as a packed or trayed bubble column, and the reactive rectifying section as a packed column. With respect to the feed configuration, the feeding of monoesters to the RD column significantly intensifies the polyester process as compared to an anhydrous reactant fed to the column. Moreover, the product transition time in this configuration is also significantly reduced as compared to the other configurations.