Impact of de-ionized water on changes in porosity and permeability of shales mineralogy due to clay-swelling

Hydraulic fracturing is widely applied for economical gas production from shale reservoirs. Still, the swelling of the clay micro/nano pores due to retained fluid from hydraulic fracturing causes a gradual reduction of gas production. Four different gas-bearing shale samples with different mineralogical characteristics were investigated to study the expected shale swelling and reduction in gas permeability due to hydraulic fracturing. To simulate shale softening, these shale samples were immersed in deionized (DI) water heated to 100 °C temperature and subjected to 8 MPa pressure in a laboratory reactor for 72 hours to simulate shale softening. The low-temperature nitrogen adsorption and density measurements were performed on the original and treated shale to determine the changes in micro and nano pore structure. The micro and nano pore structures changed, and the porosity decreased after shale treatment. The porosity decreased by 4% for clayey shale, while for well-cemented shale the porosity only decreased by 0.52%. The findings showed that the initial mineralogical composition of shale plays a significant role in the change of micro and nano pores and the pore structure alteration due to retained fluid from hydraulic fracturing. A pore network model is used to simulate the permeability of shale used in this study. To define pore structure properties, specific factors such as porosity, pore size, pore throat distribution, and coordination number were used. Furthermore, the anisotropy characteristics of shale were integrated into the model via a coordination number ratio. Finally, the change in permeability due to shale softening was determined and compared with untreated with the progress of shale softening. The simulation showed that the permeability of Longmaxi shale could decrease from 3.82E–16 m2 to 4.71E–17 m2 after treatment.

Phosphorus-Rich Ash from Poultry Manure Combustion in a Fluidized Bed Reactor

The aim of this study was to examine the physico-chemical and phase characteristics of ash obtained in the process of the combustion of Polish poultry manure in a laboratory reactor with a bubbling fluidized bed. Three experiments, differing in the grain size and morphology of the raw material, the method of its dosing and the type of fluidized bed, were carried out. The contents of the main chemical components and trace elements in the obtained ash samples were determined using WDXRF, and the phase composition was examined through the XRD method. The morphology and the chemical composition of grains in a given micro-area using the SEM/EDS method were also investigated. The highest concentration of phosphorus (from 28.07% wt. to 29.71% wt. as P2O5 equivalent), the highest proportion of amorphous substance (from 56.7% wt. to 59.0% wt.) and the lowest content of unburned organic substance (LOI from 6.42% to 9.16%) (i.e., the best process efficiency), was obtained for the experiment in which the starting bed was quartz sand and poultry manure was fed to the reactor in the form of pellets. It has been calculated that in this case, the amorphous phase contains more than half of the phosphorus. The method of carrying out the combustion process has a significant impact on the phase composition and, consequently, on the availability of phosphorus.

Impact of Hydraulic fracturing on Mineralogy on Change in Micro and Nano Porosity and Permeability of Shales

Hydraulic fracturing is widely applied to economical gas production from shale reservoirs. Still, the gradual swelling of the clay micro/nanopores due to retained fluid from hydraulic fracturing causes a gradual reduction of gas production. Four different gas-bearing shale samples were investigated to quantify the expected shale swelling due to hydraulic fracturing. These shale samples were subject to heated deionized (DI) water at 100°C temperature and 1.2 MPa pressure in a laboratory reactor for 72 hours to simulate shale softening. The low-temperature nitrogen adsorption and density measurements were performed on the original and treated shale to determine the micro and nanopore structure change. The micro and nanopore structures changed during shale swelling, and the porosity decreased after shale treatment. The porosity decreased by 4% for clayey shale, while for well-cemented shale the porosity only decreased by 0.52%. The findings showed that the initial mineralogical composition of shale plays a significant role in the swelling of micro and nanopores and the pore structure alteration due to retained fluid from hydraulic fracturing. A pore network model was used to compare the permeability due to shale softening. The permeability results show a reduction from 3.76E-16 m2 to 2.62E-17 m2 after treatment based on the simulations.

Dependence of titanium (IV) extraction on conditions of modeling decomposition of sphenic and perovskite concentrates.

The decomposition of sphenic and perovskite concentrates was simulated using HCl, H2SO4and HNO3acids. Modeling was carriedout in atmospheric laboratory reactor, as well as in autoclave. Parameters of decomposition process were established under which titanium extraction was 85–90 %.

Method for attachment of TiO2 using design of experiments: application to the photocatalysis of a model pollutant methylene blue dye

The preparation of titanium dioxide (TiO2) supported on a glass plate by heat attachment method is presented. With the use of response surface methodology based on a central composite design we investigated the influence of the experiment parameters of the TiO2 deposition (temperature of calcination (T), time of calcination (ts) and the concentration of TiO2 ((TiO2))) on photocatalytic activity of the semiconductor for the degradation of a model pollutant: methylene blue. The analysis of variance results showed that the selected quadratic model with interaction (R2 = 0.9802) was statistically significant. The experimental results showed that the degradation quantity of methylene blue increased when the ts value increased and T decreased. We have evaluated the photocatalytic activity of this supported catalyst (TiO2-GP) with a laboratory reactor under natural condition; the maximum removal (96.03%) was obtained at ts = 331 min, T = 559 °C and (TiO2) = 2.38 g/l. The method of desirability function was used to obtain the best combination of factor settings for achieving the maximum of degradation quantity ((TiO2) = 2.6 (g/l), T = 600 (°C) and ts = 240 (min)). The additional tests on the catalyst plates confirmed that the deposits keep their catalytic activity for several cycles of use.

Catalytic combustion of propane on Pd-modified Al–La–Ce catalyst – from reaction kinetics and mechanism to monolithic reactor tests and scale-up

A propane combustion catalyst was prepared by supporting of Pd on optimized multiphase composition, containing Al2O3, La2O3 and CeO2 aiming for possible application in catalytic converters for abatement of propane in waste gases. The catalyst characterization has been made by N2- physisorption, XRD, SEM/EDX, TEM and XPS. The obtained values for reaction order towards propane and oxygen are 0.57 and 0.14, respectively. The negative reaction order towards the water vapour (−0.26) shows an inhibition effect of the water molecules. According to the kinetics model calculations, the reaction pathway over Pd-modified La–Ce catalyst proceeds most probably through Langmuir–Hinshelwood mechanism with adsorption of propane and oxygen on different types of sites, dissociative adsorption of oxygen, whereupon water molecules compete with propane molecules for one and the same type of adsorption sites. For practical evaluation of the synthesized material, a sample of Pd/Al2O3–La2O3–CeO2, supported on rolled Al-containing stainless steel (Aluchrom VDM®) to form a single monolithic channel was prepared and tested. Two-dimensional heterogeneous models were used to simulate the propane combustion from laboratory reactor to full-scale adiabatic monolithic converter for ensuring an effective abatement of propane emissions.

Application of a grey-box modelling approach for the online monitoring of batch production in the chemical industry

Model-based solutions for monitoring and control of chemical batch processes have been of interest in research for many decades. However, unlike in continuous processes, in which model-based tools such as Model Predictive Control (MPC) have become a standard in the industry, the reported use of models for batch processes, either for monitoring or control, is rather scarce. This limited use is attributed partly to the inherent complexity of the batch processes (e. g., dynamic, nonlinear, multipurpose) and partly to the lack of appropriate commercial tools in the past. In recent years, algorithms and commercial tools for model-based monitoring and control of batch processes have become more mature and in the era of Industry 4.0 and digitalization they are slowly but steadily gaining more interest in real-word batch applications. This contribution provides a practical example in this application field. Specifically, the use of a grey-box modeling approach, in which a multiway Projection to Latent Structure (PLS) model is combined with a first-principles model, to monitor the evolution of a batch polymerization process and predict in real-time the final batch quality is reported. The modeling approach is described, and the experimental results obtained from an industrial batch laboratory reactor are presented.

SYNTHESIS OF A NEURO-FUZZY MODEL OF RADICAL POLYMERIZATION PROCESS KINET-ICS

There was considered the kinetic scheme of the processes of methyl methacrylate and styrene polymers synthesis by the radical polymerization method. It is shown that the main difference in the above kinetic schemes is observed in the last stage of the reaction and lies in the mechanisms of breaking the polymer chain – by recombination for polystyrene and by disproportionation for polymethyl methacrylate. There were given the well-known mathematical models describing the kinetic scheme for the polymerization of methyl methacrylate and styrene and showing the dependence of the degree of monomer to polymer conversion on the time. It is shown that each of the presented models contains a large number of empirical constants, the values of which differ by orders of magnitude among different researchers, which greatly complicates the use of these models and often leads to confusion and incorrect results of simulation modeling. In addition, some of the known models do not take into account the phenomenon of auto-acceleration of the process - the gel effect inherent in the radical polymerization of styrene and, to a greater extent, methyl methacrylate. Thus, the necessity of developing a simpler in its structure adequate mathematical model of the processes under consideration based on the methods of neuro-fuzzy modeling was substantiated. The results of studying the rate of polymerization of methyl methacrylate and styrene in a laboratory reactor under different initial conditions were used as initial data in the development of a fuzzy model. With the help of an adaptive neuro-fuzzy system, there were obtained primary models of the Takagi-Sugeno type, after processing which, we obtained the final fuzzy model. The accuracy of the obtained model was verified by conducting a comparative analysis of the results of process simulation with different initial data and results obtained in a laboratory reactor. The good data convergence were shown and recommendations were given for using the model.

Hot Water Extraction: Short Rotation Willow, Mixed Hardwoods, and Process Considerations

Short rotation woody crops (SRWC) like shrub willow are highly productive biomass resources of interest for energy and fuel applications. Hot water extraction (HWE) as an upgrading tool to enable the use of willow biomass in pellet applications has been proposed, and is of increasing interest. This study treats willow and mixes of willow and conventional mixed hardwood feedstock with HWE in a tumbling laboratory reactor to elucidate the effects of time, temperature, feedstock mixes, and other process considerations (water:biomass ratio, presteaming, counter-current processing) on mass removals and other extraction outcomes (e.g., sugar, acetate, and furan yields). Results demonstrated alignment of extraction outcomes with P-factor from 155 °C to 175 °C, with a good compromise of removed mass and co-product potential in the range from 575–800 P-factor. The preferred condition was chosen as 575 P-factor. HWE of mixes of willow and hardwood feedstocks showed a linear response of extraction outcomes to willow:hardwood ratios. Testing of water:biomass ratios demonstrated that this is a significant consideration, with each outcome being affected somewhat differently, and indicating that HWE is more diffusion dependent than expected. Presteaming shows little to no effect on extraction outcomes, while multi-stage cooks simulating counter-current operation indicate a significant potential value in counter-current extraction.