Process integration,modelling and optimisation for energy saving and pollution reduction

Energy saving, global warming and greenhouse gas emissions have become major technological, societal, and political issues. Being closely related to energy supply, they are of a strategic importance. Various conferences are being organised for providing international venues for closer cooperation among researchers. The series of conferences “Process Integration, Modelling and Optimisation for Energy Saving and Pollution Reduction” (PRES) play a pioneering role in contributing to the solution of the related problems through presenting new methodologies and initiating cooperation among participants that often result in international projects. The PRES conferences have been dedicated both to the theoretical and to the practical aspects of energy saving and pollution reduction. The PRES series, established thirteen years ago, was originally dedicated to energy integration and improving thermal efficiency. Following the new challenges and priorities, the scope of the conferences has been extended to include all energy and pollution prevention related issues. This contribution focuses on the period covered by PRES, reviewing at least some major presentations contributing to the development of process integration and optimisation tools for energy saving and pollution reduction. The development of the mathematical models has been covered as well, since it is closely related to the area.     

Improving the relaxivity by dimerizing Gd-AAZTA: Insights for enhancing the sensitivity of MRI contrast agents

The synthesis of a dimeric derivative of Gd-AAZTA is reported. It retains the basic properties of the parent complex (q = 2, high stability) and displays a relaxivity of 14.0 mM^?1 s^?1 at 20 MHz and 298 K. The outstanding relaxivity is the result of the increased molecular reorientational time and of the contribution arising from 4 to 5 water molecules in the second coordination sphere of the Gd(III) ions.     

Nanoparticle synthesis completed with in situ catalyst preparation performed on a high-pressure high-temperature continuous flow reactor

The present communication reports a three-way strategy on utilizing a newly developed continuous high-pressure, high-temperature micro-fluidic reactor to synthesize and modify nanoparticles (NPs) and produce catalytically relevant materials in one flow. Well-defined platinum nanoparticles have been synthesized within a few seconds and in a highly controlled fashion. By changing the applied temperature, flow rate and the type of solvent, the size and the surface morphology of the resulting nanoparticles was changed and tuned on-the-fly. It was also shown that the primarily synthesized NPs can be successfully modified further by using them as seeds in the same flow from where they were formed, by applying the seeded growth method, which resulted in increased particle size and the formation of well-defined but randomly distributed shapes. Furthermore, after synthesizing, the Pt nanoparticles were adsorbed onto the surface of well-known support materials in the same flow to provide in situ production of commercially relevant Pt/SiO₂ catalysts. The in situ prepared catalytically active materials were tested in the hydrogenation of cinnamaldehyde and showed high activity.     

Simulation of uplooking and downlooking high-resolution radiance spectra with two different radiative transfer models

Measurements of up-looking spectral radiances measured during the Convection and Moisture Experiment and down-looking spectral radiances measured at one of the Atmospheric Radiation Measurement sites are compared with simulations with use of two different line-by-line models. Simulations are performed in tightly controlled conditions to verify the behavior of the models. Spectra computed at higher samplings are used to study the spectral structure of the differences between simulations and measurements. A revised list of water vapor spectroscopic parameters is used to test the impact of improved spectroscopic data on the accuracy of the line-by-line calculations. The sensitivity of the results to errors that result from uncertainties in the input atmospheric temperature and humidity profiles is also investigated.     

Hybrid fuzzy convolution modelling and identification of chemical process systems

This paper looks at a new method of modelling nonlinear dynamic processes, using grid-type Takagi-Sugeno fuzzy models and a priori knowledge. The proposed hybrid fuzzy convolution dynamic model consists of a non-linear fuzzy steady-state static and a gainindependent impulse response model-based dynamic part. The modelling of nonlinear pH processes is chosen as a realistic case study for demonstration of the proposed modelling approach. The off-line identified hybrid fuzzy convolution model is shown to be capable of modelling the nonlinear process and providing better multiple-step prediction than the conventional grid-type Takagi-Sugeno fuzzy model.     

Constraint propagation on quadratic constraints

This paper considers constraint propagation methods for continuous constraint satisfaction problems consisting of linear and quadratic constraints. All methods can be applied after suitable preprocessing to arbitrary algebraic constraints. The basic new techniques consist in eliminating bilinear entries from a quadratic constraint, and solving the resulting separable quadratic constraints by means of a sequence of univariate quadratic problems. Care is taken to ensure that all methods correctly account for rounding errors in the computations. Various tests and examples illustrate the advantage of the presented method.     

Temperature-Induced Change of Water Structure in Aqueous Solutions of Some Kosmotropic and Chaotropic Salts

The hydrogen bond structure of water was examined by comparing the temperature dependent OH-stretching bands of water and aqueous NaClO₄, KClO₄, Na₂SO₄, and K₂SO₄ solutions. Results called attention to the role of cations on top of the importance of anions determining the emerging structure of a multi-layered system consisting single water rings or multi-ring water-clusters.     

Free radicals in gamma-irradiated polyamide 6 from the point of view of chemical ESR-dating

Polyamide 6 was irradiated with gamma rays in air at room temperature with a radiation dose of 17 kGy. The arising composite spectrum indicates the presence of two types of free radicals. The ratio of spectral lines was measured for the time period of 45 days. As the rate constants of decay of individual types of free radicals are different, the intensity ratio of lines of the composite spectrum significantly changes in the course of decay. It has been pointed out that this temporal dependence of the line ratio can be used for determining the time interval between the radiation impact and the measurement of ESR spectrum. The possibilities of using this information for the purpose of retrospective chronodosimetry are discussed.     

The effects of pH on the molecular distribution of water soluble ruthenium(II) hydrides and its consequences on the selectivity of the catalytic hydrogenation of unsaturated aldehydes

The effect of pH on the formation and equilibrium distribution of the water soluble ruthenium hydrides [HRuCl(TPPMS)₂]₂, [HRuCl(TPPMS)₃] and [H₂Ru(TPPMS)₄] (TPPMS=(3-sulfonatophenyl)diphenylphosphine sodium salt) was studied in aqueous solution by pH-potentiometric and

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NMR methods. Depending on the pH, [RuCl₂(TPPMS)₂]₂ and its hydrido-derivatives hydrolyse extensively, giving rise to formation of hydroxo-ruthenium complexes. It was established that at pH≤3.3 the dominant ruthenium(II) species was [HRuCl(TPPMS)₃], while at pH≥7 it was [H₂Ru(TPPMS)₄]. While [HRuCl(TPPMS)₃] catalyzed the slow, selective hydrogenation of the C=C bond in trans-cinnamaldehyde, [H₂Ru(TPPMS)₄] was found an active and selective catalyst for C=O reduction. Consequently, the selectivity of the hydrogenation of trans-cinnamaldehyde could be completely inverted by minor changes in the solution pH, shifting the equilibrium between [HRuCl(TPPMS)₃] and [H₂Ru(TPPMS)₄].