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Under high-temperature batch fluidized bed conditions and by employing Juye coal as the raw material, the present study determined the effects of the bed material, temperature, OC/C ratio, steam flow and oxygen carrier cycle on the chemical looping combustion of coal. In addition, the variations taking place in the surface functional groups of coal under different reaction times were investigated, and the variations achieved by the gas released under the pyrolysis and combustion of Juye coal were analyzed. As revealed from the results, the carbon conversion ratio and rate were elevated significantly, and the volume fraction of the outlet CO2 remained more than 92% under the oxygen carriers. The optimized reaction conditions to achieve the chemical looping combustion of Juye coal consisted of a temperature of 900 °C, an OC/C ratio of 2, as well as a steam flow rate of 0.5 g·min−1. When the coal was undergoing the chemical looping combustion, volatiles primarily originated from the pyrolysis of aliphatic CH3 and CH2, and CO and H2 were largely generated from the gasification of aromatic carbon. In the CLC process, H2O and CO2 began to separate out at 270 °C, CH4 and tar began to precipitate at 370 °C, and the amount of CO2 was continuously elevated with the rise of the temperature.

The impacts of FeS catalysts on the hydromodification and structural evolution of lignite were investigated using Fourier transform infrared spectroscopy, nuclear magnetic resonance, and X-ray photoelectron spectroscopy. The results indicate that the caking property of lignite can be significantly improved in the presence of the FeS catalyst. When 6.0 wt % FeS was added, the maximum caking index (G RI) of modified coal reached 95. During the hydromodification, FeS has little effect on the intrinsic water gas shift reaction, but it can increase the CO conversion by promoting the decomposition and hydrogenation of coal so that more active hydrogen is generated and introduced into modified coal. FeS is conducive to the rupture of distal aliphatic groups in the extractible solutes, which promotes the entrance of hydrogen into the aromatic nucleus (Har) and α positions (Hα) of asphaltenes and β positions (Hβ) of preasphaltenes. After the catalytic hydromodification, the longer side chains or bridge bonds break and are hydrogenated to form the aliphatic structures with a shorter chain or a higher branched degree. Meanwhile, more oxygen-containing functional groups were removed along with the reduction of volatiles in the modified coal. The synergistic effect of FeS on these factors is favorable for the generation of plastic materials, which contributes to the development of the caking property of lignite.

Large coal agglomerates (cakes), which form in slow heating fixed-bed commercial gasifiers, result in low carbon efficiency and carbon loss in the ash assemblage. In an earlier study, laboratory-sc...

The utilization of high-sulfur coal is becoming more urgent due to the excessive utilization of low-sulfur, high-quality coal resources, and sulfur removal from high-sulfur coal is the most important issue. This paper reviews the speciation, forms and distribution of sulfur in coal, the sulfur removal from raw coal, the thermal transformation of sulfur during coal pyrolysis, and the sulfur regulation during coal-blending coking of high organic-sulfur coals. It was suggested that the proper characterization of sulfur in coal cannot be obtained only by either chemical method or instrumental characterization, which raises the need of a combination of current or newly adopted characterization methods. Different from the removal of inorganic sulfur from coal, the organic sulfur can only be partly removed by chemical technologies; and the coal structure and property, particularly high-sulfur coking coals which have caking ability, may be altered and affected by the pretreatment processes. Based on the interactions among the sulfur radicals, sulfur-containing and hydrogen-containing fragments during coal pyrolysis and the reactions with minerals or nascent char, regulating the sulfur transformation behavior in the process of thermal conversion is the most effective way to utilize high organic-sulfur coals in the coke-making industry. An in-situ regulation approach of sulfur transformation during coal-blending coking has been suggested. That is, the high volatile coals with an appropriate releasing temperature range of CH4 overlapping well with that of H2S from high organic-sulfur coals is blended with high organic-sulfur coals, and the C–S/C–C bonds in some sulfur forms are catalytically broken and immediately hydrogenated by the hydrogen-containing radicals generated from high volatile coals. Wherein, the effect of mass transfer on sulfur regulation during the coking process should be considered for the larger-scale coking tests through optimizing the ratios of different coals in the coal blend.

CaO-containing carbon pellets (CCCP) were successfully prepared from well-mixed coking coal (CC) and calcium oxide (CaO) and roasted at different pyrolysis temperatures. The effects of temperature, pore distribution, and carbon structure on the compressive strength of CCCP was investigated in a pyrolysis furnace (350–750°C). The results showed that as the roasting temperature increased, the compressive strength also increased and furthermore, structural defects and imperfections in the carbon crystallites were gradually eliminated to form more organized char structures, thus forming high-ordered CC. Notably, the CCCP preheated at 750°C exhibited the highest compressive strength. A positive relationship between the compressive strength and pore-size homogeneity was established. A linear relationship between the compressive strength of the CCCP and the average stack height of CC was observed. Additionally, a four-stage caking mechanism was developed.

The objective was to evaluate the effect of glass transition on chemical properties, caking, and flowability of soymilk powder during storage. Samples were stored for 18 weeks under different water activities (Aw: 0.328–0.902) and temperatures (T: 10–55 °C). Chemical changes (antioxidant capacity, phenolic compounds content, and color) and powder flow properties were evaluated using dynamic rheological measurements of the amorphous powder at glassy and rubbery states. The results showed that chemical changes occurred during storage as an effect of Aw and temperature. However, the physical state (glassy × rubbery) had a more relevant role in the degradation of the components. The flow properties of the soymilk powder showed that cohesion, as well as the normalized basic flow energy (NBFE), can be correlated to the rubbery state. The temperature showed higher NBFE values when sample was stored in rubbery state. The results can help understand the role of glass transition on soymilk powder stability.

The aim of this work was to establish the maximum stability conditions of maltodextrins and corn syrups obtained by spray drying with different levels of starch hydrolysis as dextrose equivalent (DE) 10, 20, 30 and 40 from a thermodynamic study of sorption at 25, 35 and 40°C. These storage conditions were correlated with the hygroscopicity, glass transition temperature (Tg) and external morphology of these powders to minimize physical phenomena such as caking. The conditions of maximum stability according to the minimum integral entropy (DSint) for maltodextrins (DE 10 and 20) fluctuated between aW of 0.12 to 0.25 at 25°C with hygroscopicity of 26 % and Tg of 112 ° C, while for corn syrups (DE 30 and 40) aW between 0.03 to 0.05 at 25°C, with hygroscopicity of 36% and Tg of 89°C; For the same value in DE as the temperature increases, the humidity (M) and the aW of maximum stability decrease, while for the same temperature, the increase in DE also decreases the humidity (M) and aW of maximum stability, maintaining their structural integrity without compaction; in extreme conditions, the powders showed a greater or lesser degree of caking.

Excess vapor content in the spray-drying system leads to various issues such as undesired agglomeration or caking of products. The majority of the drying in spray-dryers occurs during the initial p...

The changes in fractal structure during high-temperature (1200°C) carbonisation of a Chinese non-caking coal were studied in situ by synchrotron radiation small-angle X-ray scattering (SAXS). The r...

The coconut sugar powder produced by vacuum drying and conventional method has high hygroscopicity due to its high sugar content (mostly sucrose). Therefore, it is easier for caking to occur during storage. An anticaking agent such as tricalcium phosphate was therefore added to the powder to maintain its stability. The purpose of this research was to determine the physical characteristics of amorphous and crystalline coconut sugar after the addition of tricalcium phosphate (TCP) in different concentrations. The two types of coconut sugar were prepared by the conventional method, which gave it a predominantly crystalline structure, and the vacuum drying method, which gave it a mainly amorphous structure. The TCP at concentrations 0, 0.5%, and 1% was added to both types of the coconut sugar. The addition of the anticaking agent affected the water sorption of coconut sugar by decreasing the monolayer water content for both types of coconut sugar. TCP seemed to give more significant effect on decreasing the hygroscopicity of crystalline coconut sugar than the amorphous one, while similar trends were obtained in increasing flow ability of both types of coconut sugar. The capacity of TCP to cover the surface of the host coconut powder was proposed as the mechanism of TCP in decreasing hygroscopicity and increasing flow ability of the host powder.

The effects of crude oil on the microstructure and spontaneous combustion characteristics of coal were assessed, using raw coal sample and coal samples containing 5%, 10% and 15% oil. The pore structures, oxygen adsorption capacity, surface functional groups and spontaneous combustion characteristics were characterized by the LP-N2A, TG, FTIR and temperature-programmed experiments. The LP-N2A and TG tests revealed that the presence of crude oil reduced the porosity, specific surface area and pore volume in the coal sample containing crude oil, which would suppress the transport capacity of oxygen in mesopores and micropores not to adsorb on the specific active sites of coal surfaces. FTIR analysis indicated that the amount of oxygen-containing functional groups and –OH groups decreased tremendously in the coals containing crude oil, but the content of aliphatic C–H groups showed an increasing trend. Moreover, the values of A(CH2)/A(CH3), Ahy/Aar, Aoxygen/Aar all decrease gradually with the rising crude oil contents, indicating that the crude oil reduced the average alkyl chain length and compressed the space between aromatic clusters. The results of temperature-programmed experiments showed that O2 consumption and CO production rates decreased gradually with the increase in crude oil content. The results were in agreement with the varying trend of characterization of microstructure and function groups obtained by LP-N2A, TG and FTIR tests. Furthermore, the Pearson correlation coefficient cleared that the breaking of long aliphatic chains of aromatic rings and reduction of hydrogen bonds content have a greater contribution to the suppression of spontaneous combustion than the attenuation of physical adsorption. This study concluded that crude oil lowers down the spontaneous combustion properties of coal, which could provide a reference for the prevention of spontaneous combustion of coal seam containing crude oil.

The catalytic steam gasification of Yanzhou (YZ) bituminous coal char loading with K2CO3 and CaO was studied in a fixed bed with 20 mm in inner diameter. The influence of K2CO3 on caking properties of Yanzhou bituminous coal was investigated. The relationship between carbon conversion and reaction time and catalyst loading amount of Yanzhou coal char was measured from 700 to 850°C. The effects of reaction temperature and catalyst loading amount on molar yield of the gasification gas were studied. The influence of catalyst on the microstructure of the YZ coal char was determined. The results show that K2CO3 had significant effects of caking destruction and catalytic gasification on YZ coal. The carbon conversion of YZ coal char increased with the increase of gasification temperature and K2CO3 loading amount. The addition of CaO could improve the carbon conversion of char and promoted the generation of gasification gas to some extent. The molar yield of gasification gas increased with the increase of gasification temperature, and H2 increased the most. The 002 peak of YZ coal char became lower and wider, and moved towards the lower position with the addition of K2CO3 and thus decrease the graphitization trend.

Jujube (Ziziphus jujuba Mill.) powder is hygroscopic and highly prone to caking during storage which could significantly reduce product quality. Anticaking agents are usually added to maintain flowability of powders and prevent caking. Caking behaviors of jujube powder and blends with anticaking agents (calcium stearate, magnesium stearate, and silicon dioxide at 1, 2, 3% w/w) as affected by temperature (25 °C, 35 °C, 45 °C), mixing speed (22, 73, 96 rpm), and mixing time (1, 5, 10, 15, 20 min at 25 °C) of powders exposed at 75% RH for 5 h were investigated by FT4 powder rheometer. Energy of crust that formed during caking was determined. Results showed that anticaking agents resulted in significant effect on the moisture sorption and crust strength formed during caking of jujube powders. Calcium stearate (2% w/w) proved to be the most effective to improve the flowability and delay onset of powder caking with significant reduction in the crust strength of powder cake from 170 to 2 mJ/g when powders exposed to 75% RH for 5 h at 25 °C. Mixing speed at 73 rpm and mixing time of 5~20 min could present better flowability of jujube powders and delay the onset of caking. Lower (22 rpm) and higher (96 rpm) mixing speeds and higher temperatures (45 °C) could speed up caking rate in powder blends. State diagrams established based on moisture sorption isotherm and glass transition curves showed that jujube powders with and without calcium stearate addition were stable at 25 °C when water content was lower than 0.095 and 0.088 g water/g sample, respectively.

Glass transition temperature (Tg) and degree of caking for maltodextrin with added plasticizers (glucose, maltose, and sorbitol) were investigated. Onset and offset Tgs were evaluated by differential scanning calorimetry. From the onset and offset Tg-curves and water sorption isotherm, each critical water activity (awc) value was determined (water activity at each Tg = 25 °C). The awc range between onset Tg and offset Tg was extended by the addition of plasticizers. The degree of caking increased at a water activity just above awc of onset Tg, and completely caked at a water activity just below awc of offset Tg. Effect of aw on the degree of caking became more gradual with the addition of plasticizers because of the extended awc range. According to the dependence of viscosity on temperature and water activity, a predictive model for the caking of amorphous powders was proposed based on the onset and offset Tg curves.

Granular fertilizers (especially those based on ammonium nitrate (AN)) tend to agglomerate during storage. The aims of this research were to develop effective anti-caking coatings for ammonium nitrate fertilizers while improving the quality of fertilizers and to optimize the composition of effective anti-caking coatings. The influence of the composition of the prepared organic coatings on the effectiveness of preventing the caking of fertilizers was studied by response surface methodology (RSM) using Box–Behnken design (BBD). Additionally, the effect of the developed anti-caking agents on the quality of fertilizers was determined by measuring the crushing strength of the granules. The prepared coatings included fatty amine, stearic acid, surfactant, and paraffin wax. Gas chromatography–mass spectrometry (GC–MS) was used to analyze these coatings. The morphology of the fertilizers were examined by scanning electron microscopy (SEM). Composition studies, based on statistical assessment, showed the coating components had a varying influence on preventing the caking of fertilizers after granulation and after 30 days of storage. The results demonstrated that increasing the content of fatty amines and reducing surfactant in the composition of coating had positive effects on caking prevention. In this study, more effective and economically viable anti-caking coatings were developed. In addition, the present work could serve as a basis to further improve anti-caking coatings.

Membrane filtration is a process of separating particles from fluids. Over time, particles are trapped within the membrane structure and on the membrane surface, forming a cake. In this paper, we develop a mathematical model for the transient blocking dynamics in a concertinaed filtration device composed of angled porous membranes and dead-ends. We examine how the inclusion of particles affects the flow dynamics, and we uncover potential inaccuracies in relying on flux–throughput curves to distinguish between caking and internal blocking dynamics. Moreover, we show that optimal filtration performance strongly depends on both the performance metric and the membrane configuration. Finally, to optimize the use of membrane area, we introduce a method for deriving a nonuniform permeance that ensures constant initial cake growth.

Dextrose Monohydrate (DMH) is a bulk chemical used in the food, beverage, and pharmaceutical industries. The caking often appeared in the crystallization of DMH. Caking is an agglomeration that can affect the product quality of DMH and is dependent on the type of impeller. This study aimed to determine the type of impeller to avoid the caking during the DMH crystallization and identify the DMH caking. The results showed that caking did not occur on the helical ribbon and anchor impeller, while caking appeared on the Rushton turbine impeller. Computational fluid mechanics (CFD) analysis showed that caking occurs due to uneven homogeneity of stirring. Fourier transform infrared (FTIR) and X-ray diffraction (XRD) studies showed that DMH caking and non-caking had the same peak pattern. Meanwhile, optical microscope and scanning electron microscope (SEM) analysis showed that the DMH caking seen agglomerate. Density analysis showed that DMH with caking was 1.257–1.350 kg/L, while the non-caking was 0.504–0.780 kg/L. Caking phenomena during the DMH crystallization can be avoided by using a helical ribbon and anchor impeller. FTIR and XRD analysis cannot be used to identify DMH caking products; meanwhile, optical microscope, SEM, and density analyzes can be used to identify DMH caking products.

Caking of food powders is highly undesirable. Many food powders are powder ingredient mixes and there is little work reported on the caking of food powder mixes. This study applied a combination of cake strength and moisture content measurements, coupled with visual assessment of the bulk powder and two particles in contact to investigate the humidity caking behaviour of the powders over time. The food powder binary mixes consisted of a 40% or 80% “sticky” powder (whey permeate WP or maltodextrin MD) and a “non-sticky” powder (salt, flour or paprika). The powders were exposed to 76% relative humidity to make the WP and MD sticky. The WP mixes had weaker but similar cake strength profiles to the WP powder. For the salt mixes with both WP and MD, there was a continuous uptake of water over time resulting in very weak salt mixes. This may be caused by lowering of the deliquescence relative humidity of salt when contacted with WP or MD. The caking behaviour of the MD mixes depended on the non-sticky powder. The MD/flour mixes had a weaker but similar profile to the MD powder, while MD/paprika and MD/WP displayed a maximum cake strength after 6–10 days.

A new method for the alkali catalytic modification of lignite in subcritical H2O–CO systems is presented, which can greatly improve its caking properties (caking index, >90). Soxhlet extraction tec...

To further the utilization of biomass for cokemaking at ironmaking facilities and to reduce CO2 emissions, carbon/carbon composite (CC) from tar and char is produced from the pyrolysis of a woody biomass with quartz-made fixed-bed reactor at 10 °C/min to 200–500 °C. Then, the optimum conditions for preparing high-strength coke by blending caking coal and CC is investigated. The specific surface areas of char and tar yields via sawdust pyrolysis are maximized at 550 °C. When the mixture of pyrolyzed char and tar produced in large quantities during the same process is co-pyrolyzed, the pore observed in prepared char completely disappears due to filling of carbonaceous materials derived from tar-pyrolysis into char pores, and char yield is improved. When the strength of the coke prepared from the mixture and pelletization of caking coal and prepared CC is investigated, the indirect tensile strength of the prepared coke tends to decrease with an increase in temperature of CC preparation. And, it was found that the optimum CC preparation temperature is 250 °C (CC250) for high-strength coke preparation. Although increasing the blending ratio of CC250 to caking-coal decreases the strength of the coke, the extent of decreasing strength is smaller than that of slightly-caking coal or pyrolyzed char blended to caking coal. The filling of carbonaceous materials derived from tar-pyrolysis into pores of sawdust char during CC preparation influences the coke strength, such that the value is greater than that of physical mixture of sawdust char and carbonaceous materials from tar prepared with individually (carbonaceous materials derived from tar not loaded into pore in char).

This work deals with caking behaviour of lactose monohydrate powders containing small amounts of amorphous lactose. The objective was to elucidate the relation between the caking ability of powder mixtures and the crystallisation behaviour of amorphous lactose. Binary mixtures consisting of amorphous lactose and α-lactose monohydrate were prepared and tested using an accelerated caking test. Amorphous lactose samples were prepared using the freeze-drying process. Two caking devices were developed to characterize the caking ability of powders. The effect of amorphous content, relative humidity, temperature and pressure on the caking behaviour of samples was investigated. The results showed that the presence of even small amounts of amorphous lactose (as low as 0.125%) could cause caking. The more influencing parameters were found to be the relative humidity and the temperature whereas the pressure had no significant effect. The caking behaviour was shown to be closely linked with crystallisation extent and kinetics. A dimensionless time based on Avrami model for crystallisation rate was defined allowing unifying the experimental data.

Water sorption isotherm, glass transition temperature (Tg), and caking properties of maca (Lepidium meyenii Walpers) powder were investigated. A broad endothermic shift reflecting continuously distributed glass transition was detected by differential scanning calorimetry, which prompted the evaluation of onset Tg and offset Tg. From the onset and offset Tg curves and water sorption isotherm, critical water activity (water activity at glass transition temperature of 25 °C) was determined to be 0.258 for the onset Tg and 0.480 for the offset Tg. The critical water activity values were validated by isothermal mechanical relaxation measurement. Caking properties of maca powder were compared with maltodextrin. The degree of caking and cake hardness for maltodextrin increased at a water activity just above critical water activity for onset Tg. Maca powder, on the other hand, showed a small degree of caking in the water activity range of 0.225 to 0.576, and the degree of caking drastically increased at a higher water activity. The hardness of maca cakes increased gradually at water activity values greater than 0.432. Since maca powder showed a continuously distributed glass transition, the molecular mobility required for caking was considered to have been provided incrementally by the increase in water activity above critical water activity for the onset Tg.

The relevance. The industrial pulverized halurgic potassium chloride (KC1) is mixed with the finished conditioning product, which leads to its dustiness and caking, as well as losses during transportation. The enlargement of the pulverized KC1 will increase the quality of the main product, by eliminating the mixing stage of different components. The agglomeration by molding will make it possible to obtain a product of a size close to the concentrate. Investigation of agglomeration features with various binders will allow studying their influence on the efficiency of the process and the quality of the product obtained. The main aim of the research is to study the molding of pulverized halurgic potassium chloride and to establish agglomeration features of moistened fertilizer using various binders. Methods. To study the state of the agglomerates surface, electron-scanning microscopy was applied using the shooting modes BSE3D and SE with an increase to 1500X; to determine the elemental composition formed in molding and drying the fertilizer mixture, the X-ray spectral analysis was used; the quality of the resulting product was evaluated using a sieve analysis and the method of measuring the static strength of an IPG-1M instrument. The results. It was found that increasing the moisture content of the granulated mixture promotes an increase in the content of the commodity fraction to 84 % and a static strength up to 10 N/granule; the use of binders has a positive effect on the quality of the product (increasing the yield and strength of the agglomerates), and they can have fundamentally different features of molding the pulverized halurgic KC1, resulting in formation of agglomerates with significant structural differences, as confirmed using electron microscopy. The use of sodium metasilicate makes it possible to obtain agglomerates with a tight adherence of particles to each other, and the needle-shaped crystals of silicon oxide formed by the thermal decomposition of Na2SiO3·5H2O increase the roughness of the KC1 particles, the number of crystallization centers, and strengthen the bonds in the granule. When molasses are used, the resulting agglomerates have KC1 particles with intimate contact, but the remainders of the binder are visible between them; on their surface there are accumulations of microparticles with a size of 10–30 μm of the initial pulverized raw materials in the form of «shell».

The inferior coking coals as feedstocks to produce char for gasification is an effective way of utilizing the excess coking capacity and the low rank coal. Caking ability of coal is important to the characters and structures of char. For coal blends, it is affected by interactions among coal species. In this study, three different rank coals were selected to explore how the interactions among coals affect the caking ability of blends. The caking ability was evaluated by the caking index (GR.I) and the interactions were analyzed by the comparison between the experimental GR.I and theoretical one. The significantly interactions from greater and less GR.I values of the blends than those of the coals acting independently were observed and they relied on the coal types and ratios in blends. The coal species in blends played the positive effect of the interaction when the experimental GR.I value was greater than 45 of the blends. The increase of fat coal and the decrease of sub-bituminous coal and gas coal strengthened the caking ability and the swelling property of the coal blends. Oxygen content, carbon aromaticity and volatiles of single coal in blends are regarded as the factors to control the interactions of coals and the caking ability of blends.

Chinese jujube, rich in nutritional and nutraceutical values, is mostly preserved by drying in powder form. However, jujube powder is at amorphous state and prone to caking which has a negative impact on product manufacturability and quality. Effects of five different drying methods on caking of jujube powders were quantified by using the powder rheometer. In general, non-homogeneous caking of jujube powder was observed. Drying methods showed significant effect on the caking of jujube powder, powder dried by freeze drying and instant controlled pressure drop drying showed highest and lowest crust strength (622 and 170 mJ/g) at 25ᵒC, 75% RH for 5 h, respectively. Strength of caking increased with rising of RH and load. Temperature and time show coupled effect on powder caking and higher temperature could significantly accelerate caking strength of powders. When the moisture content of jujube powder was over 0.066 g/g at 25ᵒC, glass transition would happen. Structure of jujube powder would change from “amorphous glassy” to “amorphous rubbery”. Caking of particles was mainly due to sinter bridge formation and fructose was one of the main contributor to caking of jujube powder.

The study focuses on obtaining the finely ground wheat germ flour mix by employing dry mechanical activation. During the study, wheat germ is ground using DESI-11 disintegrator and mechanically activated in PM-10 centrifugal mill with the rotor speed of 1050 rpm. According to the study findings, the finely ground wheat germ flour mix obtained by dry mechanical activation possesses increased bulk density and improved water absorption capacity when compared to the product obtained from wheat germ without mechanical activation applied. The average particle size is reduced from 114 μm to 52 μm. The study findings indicate that obtaining the finely ground wheat germ flour mix by dry mechanical activation prevents the occurrence of the caking effect as well as improves the quality of baked products.

Contrast-enhanced X-ray computed tomography plays an important role in cancer imaging and disease progression monitoring. Imaging using radiopaque nanoparticle platforms can provide insights on the likelihood of nanoparticle accumulation and can enable image-guided therapies. Perfluorooctyl bromide (PFOB)-loaded nanocapsules designed for this purpose were stabilized using an in-house synthesized PEGylated polycaprolactone-based copolymer (PEG-b-PCL(Ch)) and compared with commercial polycaprolactone employing a Quality-by-Design approach. PFOB is a dense liquid, weakly polarizable, and immiscible in organic and aqueous solvents; thus, carefully designed formulations for optimal colloidal stabilization to overcome settling-associated instability are required. PFOB-loaded nanocapsules exhibited high PFOB loading due to the intrinsic properties of PEG-b-PCL(Ch). Settling and caking are major sources of instability for PFOB formulations. However, the PEG-b-PCL(Ch) copolymer conferred the nanocapsules enough steric impediment and polymer shell elasticity to settle without significant caking, increasing the overall colloidal stability of the formulation. Furthermore, a clear relationship between nanocapsule physical properties and X-ray attenuation was established. Nanocapsules were able to enhance the X-ray contrast in vitro as a function of PFOB loading. This nanocapsule-based platform is promising for future translational studies and image-guided tumor therapy due to its enhanced contrastability and optimal colloidal stability.

3.1 Water activity is related to water vapor pressure in a material, and it is a useful parameter relating to glass transition, water content and water plasticization. The glass transitions of dairy solids, particularly that of lactose, determine the dehydration characteristics and successful spray-drying conditions of dairy liquids. Water and glass transition relationships assist in the selection of spray-drying parameters as well as required storage conditions. A critical water activity and glass transition-related strength of dairy solids are useful in the formulation of dairy food with desired physicochemical stability in processing and storage. 3.2 Caking is a common root of many problems encountered when handling powders and can lead to unwanted shutdowns, client claims and product recycling/rejection due to the clogging of conveying lines, feeding devices and storage silos. Caking can be defined as a formation of material bonds at the points of contact between particles that leads to undesired and uncontrolled agglomeration of powders. It is a very complex process bringing into play a multitude of interactions and mechanisms resulting from variations in environmental conditions, in particular those of temperature and relative humidity. The objective of this chapter is to describe the fundamental mechanisms of powder caking and especially those involved in the caking of dairy powders. 3.3 This chapter presents the structural changes at protein/aggregate scale and the changes of functionalities (water-holding capacity, viscosity, foaming, emulsifying and gelling properties) resulting from the pre-texturizing of whey proteins by heating in dry state. The first part of this chapter describes the main chemical/structural modifications occurring during protein dry-heating (limited protein unfolding, Maillard reaction, dehydration reactions) and the specificities of the aggregation reactions that are controlled by molecular mobility (or a w ) and the presence of heat-sensitive compounds (type and amount of sugars). Then, the second part of the chapter describes the functionalities of the pre-texturized whey protein by dry-heating. The change of functionalities can be huge, as shown for the modification of viscosity of protein solutions after whey protein dry-heating at alkaline pH (protein particles are able to trap up to 30g of water per g of protein). The strength of the whey protein gels is increased two-fold by the dry-heating treatment, favoring the formation of soluble aggregates. The change in the foaming properties after whey protein dry-heating is much more limited. 3.4 The perceived quality of dairy powders obtained by spray-drying depends on their functional properties, i.e., their ability to flow easily and rehydrate quickly without lump formation. These requirements can be achieved provided that the physicochemical properties of the powders are mastered by an adequate choice of formulation and spray-drying conditions. On one hand, this chapter presents the impact of the spray-drying conditions on the physicochemical characteristics of the resulting dairy powders and highlights the tremendous role of the evaporation rate in the particle structure and surface composition. On the other hand, the influence of the main powder physical properties (particle size, shape, microstructure and surface mechanical properties) on flowing properties and rehydration capacity is discussed through examples of dairy powders produced by spray drying. In order to complete this discussion of the link between spray-drying conditions, physicochemical properties and functionalities, the main analytical methods used to assess spray-dried dairy powder characteristics are briefly reviewed throughout the chapter. 3.5 Initial milk contamination may occur due to intramammary infections, microorganisms on the external udder surface, poorly sanitized handler hands and milking equipment. During the refrigeration, storage and transport stages, lapses in hygienic-sanitary conditions can lead to milk contamination from pathogenic and spoilage microorganisms. Once raw milk reaches the processing plant for dehydration, it undergoes processes including cooling, heat treatments, evaporative procedures and membrane filtration in order to inhibit microbial growth and destroy microorganisms. Following thermal treatments and membrane filtration, caution should be taken to ensure the hygienic-sanitary conditions of equipment and utensils to avoid product recontamination. All the stages of dried dairy products (from milking to packaging) should be monitored to guarantee the quality and microbiological safety of these foods.

Ammonium nitrate fertilizers have a tendency to cake during storage. The aim of this study was to examine the effectiveness of organic coatings for preventing the caking of ammonium nitrate fertilizers and to assess the influence of the composition and physicochemical properties of the anti-caking agents used as coatings for fertilizers on their effectiveness. CAN (calcium ammonium nitrate) and AN (ammonium nitrate) fertilizers were coated with three anti-caking agents. A GC&ndash, MS technique was used for the identification and quantitative determination of the composition of the organic coatings. The influence of the following physicochemical parameters of the preparations was assessed: density, viscosity, melting point, water content, and base number. The effectiveness of anti-caking agents was determined by measuring the force needed to crush the clumped uncoated and coated fertilizers, which were previously subjected to thermal cycles under load. Composition studies showed that all the tested preparations contained hexadecylamine and octadecylamine in comparable amounts and a slack wax. The results demonstrate that the key parameters of an effective anti-caking agent are low water content, appropriate viscosity, and appropriate content of fatty amines. This study can facilitate the development of innovative coatings with similar or higher efficiency, yet with a reduced negative impact on the environment.

peer-reviewed Low and high protein dairy powders are prone to caking and sticking and can also be highly insoluble; with powder storage conditions an important factor responsible for such issues. The aim of this study focused on the bulk and surface properties of anhydrous and humidified spray-dried milk protein concentrate (MPC) powders (protein content ~40, 50, 60, 70 or 80%, w/w). Water sorption isotherms, polarized light and scanning electron micrographs showed crystallized lactose in low protein powders at high water activities. High protein systems demonstrated increased bulk diffusion coefficients compared to low protein systems. Glass transition temperatures, α-relaxation temperatures and structural strength significantly decreased with water uptake. CLSM measurements showed that humidified systems have slower real time water diffusion compared to anhydrous systems. Overall, the rate of water diffusion was higher for low protein powders but high protein powders absorbed higher levels of water under high humidity conditions.

The evolution of inorganic-gases (H2, CO, CO2 or H2O) and hydrocarbon gases CH4, C2(C2H4, C2H6), or C3(C3H6 + C3H8) during the carbonization of caking coals is examined to clear the influence of the evolution amount of these gases on the Gieseler maximum fluidity (MF) and coke strength (DI15015). The samples are carbonized at 3 °C/min up to 1000 °C in high-purity He. The MF and the evolution profile of gases depend on the coal type. A negative relation exists between evolution amounts of gases, except for H2, until initial softening temperature (IST) and MF values. Additionally, the evolution amounts of inorganic gases, except for H2, until the IST increase with the increase of the carboxyl (COOH) group contents in raw coal. Moreover, the MF values trends to decrease with the increase in the COOH in raw samples. Thereby, it is found that the inherently-present coal-O adverse affect coal fluidity. Drum index (DI15015) of coke increases with the increase of C%-dry ash free (daf), fixed carbon (FC) %-dry, and reflectance (R0) vol% in raw coal, while the values decrease with the increase O%-daf and volatile matter (VM) %-dry. The DI15015 values exhibit an increasing trend with regard to the amount of the evolved H2 or CH4 during the carbonization. However, the values decrease as the amount of O-containing gases increased. A similar trend is observed in semi-coke and coke, where the values decrease as the remaining O% increased. Although the proportion of turbostatic-C (T-carbon) in coke depends on the coal type, DI15015 increases as the proportion of T-carbon increased. Therefore, it is found that the coal-O also has an adverse influence on coke strength.

Additive water is usually needed to preserve 9–11% moisture content of blended coal in the stamp-charging coking process, which in fact is unfavorable for coking property. An insight into the improvement of coking property of coal blends with much low-rank coal (long flame coal SFC, lignite HLH) by regulating additive water was proposed in terms of its effects on the metaplast fluidity and the particle agglomeration behavior. The results indicate that the cohesiveness of gas coals (GC) can be properly enhanced by adding water. The restrictions on the condensation of aromatic structures and the break-up of –CH2– structure and the development of the polyhydroxy groups in aromatic structures are favorable to increase the fluidity of metaplast after adding water, as demonstrated by the optical texture and FTIR analysis of the semicoke (450 °C). The great difference in the hydrophilic properties for various rank coals leads to the particle agglomeration of gas coal and fat coal (GC and FC), which makes them difficult to mix uniformly with SFC after adding water, thus reduces the coking property. A reasonable approach of adding water suggests that H2O and SFC should be well mixed prior to blending with caking coals, which can lead to a uniform particle distribution and a better coking property. This approach promotes the direct and efficient utilization of low-rank coal (especially lignite) by the blending coking with no or less drying and dewatering processes.

Several research studies have been performed to minimise the hygroscopicity of ammonium nitrate for increasing its commercial value and decreasing the nitrogen content. In this study, the hygroscopicity of ammonium nitrate was reduced using silicic acid, calcium lignosulfonate, and sodium silicate in the two-stage vacuum ammonium nitrate production process. Degradation of ammonium nitrate was observed after two years of storage, which is considered a standard by the European Fertilizer Manufacturers Association., Chemical engineering, Nitrogenous fertiliser; Sodium silicate; Silicic acid; Calcium lignosulfonate

This work deals with the phase transition of anhydrous lactose in solid-state due to moisturizing and subsequent crystallization and caking. It was found that anhydrous lactose is converted to lactose monohydrate when exposed to ambient moisture. The conversion rate and the kinetics of transformation were investigated at various temperatures and RH (15 to 40 °C and 70% to 95% RH). The results showed that the kinetic rate and the conversion increase with RH and T. The limiting step was the crystallization of anhydrous β-lactose. A simple kinetic law for the global rate of transformation was developed. The rate constants and the activation energy were calculated by comparison between the experimental data and the model. The effect of storage conditions on the caking behavior and kinetics of anhydrous lactose was also investigated. The results highlighted that the caking of powders was directly related to the fractional conversion of anhydrous lactose.

We proposed a low-temperature rapid pyrolysis treatment (LTRP) to modify the caking property of a sub-bituminous coal. The coal was thermally treated in a rotating furnace in the temperature range 320–500 °C at a heating rate of ca. 80 °C/min. We also conducted an integrated investigation on some physicochemical properties, which were characterized by ultimate analysis, Fourier transform infrared spectrometer, X-ray photoelectron spectroscopy, pore volume, scanning electron microscopy, and thermogravimetry, of the treated coal to determine the modification mechanism. Caking and coking properties were evaluated by caking index (G) and crucible coking experiments, respectively. The results showed that LTRP significantly increased G, which reached the maximum at 410 °C, implying the existence of an optimum temperature. Crucible coking experiments showed that structure strength and micro-strength indices of the resulting cokes were also improved by LTRP treatment. A mechanism was proposed for the modification of the caking property. Suitable upgrading degree with suitable molecular masses and low melting donor hydrogen rich species presented within the coal, which dominated the development of caking property, was important. The synergistic effect of pore volume and the contents of total acidity groups, volatile matter, hydrogen, and oxygen in the coal determined the suitable upgrading degree.

This study investigates the contribution of single coal in blends on the properties of the char produced. Three kinds of coals with varying rank and caking ability were used for the preparation of the chars at 1150 °C in muffle furnace. Char reactivity towards carbon dioxide (CRI) and char strength after reaction (CSR) were tested through the fixed-bed reactor in a laboratory scale and the tumbler, respectively. X-ray diffraction (XRD), scanning electron microscope (SEM), and nitrogen adsorption test were applied to obtain the information for the chemical and physical structures of the char. The study results show that the CRI of char increases with the increase of subbituminous coal content in blends for its role in increasing the surface area and decreasing the crystallite height (Lc) of the chars; the increase of fat coal content in coal blends causes the decrease of the CRI of chars for its contribution to the more ordered crystallite structure and less surface area. The contribution of single coal property in blends to the CSR of chars is just contrary compared to its contribution to the CRI of the chars. Coal blends with high volatile yield and low GR.I value would cause higher surface area and lower crystallite height of char. The CRI of the char can be well predicted by GR.I value and volatile yield of the coal blends quantitatively: CRI ( % ) = -0 .029 G R . I + 1.995 V daf − 57.937 , which is of certain theoretical guiding significance for gasification of char from coal blends.

Caking of crystals leads to a great deal of negative impact on the quality of products leading to extra cost to restore the products to its original state before caking. It is therefore an undesired phenomenon that should be investigated and inhibited. This review considers particle issues (particle science and technology) in a crystallization view (crystallization science and engineering). 1. Characterization. Caking indices and the relevant characterization methods are classified. Their advantages and disadvantages are summarized. Particularly, potential novel characterization methods, e.g. image analysis technique and its application in analysis of caking ratio, are discussed. 2. Mechanisms. Caking process is organized into three stages: moisture sorption, then liquid bridge, and finally crystal bridge. The mechanisms are reconsidered with recent studies (e.g. mass transfer, adhesion effect of liquid bridge, kinetic of crystal caking) and crystallization science (e.g. nucleation and growth theory, polymorphism, and phase transition). 3. Prevention. Based on particle and crystal engineering, prevention of crystals caking is discussed through controlling ambient conditions (relative humidity, temperature, liquids screening, and pressure) and improving anticaking property of crystals (particles size, particles shape, impurity, and anticaking agent). A potential method of simulating crystal caking behavior based on discrete element method (DEM) and caking mechanisms is presented. With the aid of simulation, the enhanced design of particle and crystal engineering would be available, which could be a key to control these factors systematically.

Communications devoted to analysis of the reasons and mechanisms for the formation of crystallization contacts between particles of disperse systems (primarily, NaCl) upon the removal of water from them and the contemporary methods for controlling this process with the purpose of preventing them from caking (loss of flowability) have been briefly reviewed. The main attention has been focused on works in which such processes are considered with the use of the methods and concepts of modern colloid chemistry and physicochemical mechanics of materials.

In this paper, a carbonization process for valid liquid–solid separation and upgrading of coal liquefaction residues was proposed and practiced using batch-type devices. The effect of carbonization times and temperatures on the efficiency of liquid–solid separation and product distributions were investigated using self-prepared liquid–solid mixtures (CSMs) from direct coal liquefaction. It was suggested that the carbonization temperature and blowing gases were essential to the efficient liquid–solid separation in this process, and the carbonization process was characterized by the efficient liquid–solid separation. The n -hexane soluble fractions (HS) can be largely separated from CLMs. It was remarkable that over 0.06–1.50% of HSs can be additionally produced at the higher temperatures (430 °C–500 °C). On the other hand, the obtained semi-cokes (SCs) were mainly characterized as a rich carbon-containing material with high heating values. Some of the SCs were characterized by the better caking property with the caking index ( G ) from 68.5 to 75.2. In addition, it was proved that the caking property of SCs is directly affected by the asphaltenes (ASs) instead of pre-asphaltenes (PAs).

Four types of coals, KL, XB, ZS and GD with different coal ranks, were dissolved with the organic solvent N-methyl-2-pyrrolidone at 350 °C and around 3.0 MPa pressure to obtain thermal soluble constituents (TSCs). The yield, component and maceral group were investigated as well as their coking properties, including caking index and thermoplasticity. The results indicated that the yields of the four coals were of the following order: KL > XB > ZS > GD. Based on the yield and the vitrinite content, coals were ranked from high to low. The ash contents of TSCs were significantly less than that of raw coals, and the TSCs contain more light components, leading to an increase in volatile matter. The patterns of Fourier transform infrared spectroscopy indicated that carbonyl was enriched in TSCs. Regarding the maceral group, TSCs were mainly composed of vitrinite which is the main reactive material and converts into binder phase in cokemaking process. Higher caking index values and fluidity were obtained in TSCs compared with the raw coals. The coking experiments with different amounts of TSCs addition were carried out. The results demonstrated that the proper TSCs addition could enhance the coke strength due to its high caking index and good fluidity.

Potassium chloride crystals are cubic, which often leads to caking and greatly limits their applications. This caking can be overcome by modifying the crystal shape toward sphericity. Spherical particles have a high anti-caking ability and flowability. In this work, spherical KCl particles were prepared using a simple cooling crystallization process designed to function without additives. Among the four main processes in the crystallization of spherical particles, i.e., nucleation, growth, agglomeration, and attrition, agglomeration is the greatest contributor to the formation of spherical KCl particles, which were prepared following the principle that the adhesion force must be larger than the dispersion force. The adhesion free energy between KCl particles and solvents (i.e., water, n-hexane, formamide, diazomethane, methanol, ethanol, ethyl acetate, ethylene glycol, and dimethyl sulfoxide) was calculated using the Lifshitz–van der Waals acid–base approach, and water was found to be the most appropriate solvent because of its attractive interaction with the crystals. According to the relationship between the adhesion force and dispersion forces, we found that the stirring rate should be lower than 1300 rpm. Additionally, the effects of stirring rate and cooling rate on the KCl products were investigated and optimized, and the optimal conditions were found to be 400–500 rpm and 10–15 min/°C, respectively. All of the spherical KCl products prepared under the optimal conditions show a better morphology, flowability, and anti-caking performance than the original crystals.

In order to reveal the compound effects of water immersion and pyrite on the microstructure and spontaneous combustion characteristics of non-caking coal, three coal samples from two neighboring mines were selected and prepared. The SEM observation, CO2 and N2 adsorption, XRD, XRF, FTIR tests and low temperature oxidation experiment were carried out on raw coal and soaked coal (S30). Showing that a large number of pores and fissures developed after waterlogging, especially M2 sample, the oxidation of its pyrite content (FeS2) leads to the promotion of pore development in coal matrix. Simultaneously, the presence of pyrite was more favorable for the generation of various functional groups and the maintenance of long chain aliphatic hydrocarbons during soaking. In conclusion, the presence of pyrite contributes to the micro-physical and chemical changes in the coal body during the water immersion, which further promotes the propensity for spontaneous combustion (combining data on oxygen consumption, gas products and CPT changes) of soaked coal.

A deashed oil shale (OSA) was treated using low-temperature pyrolysis treatment (LTPT) to modify its caking index (G). The treated OSA was characterized by Fourier transform infrared spectrometry, solid-state 13C nuclear magnetic resonance (13C NMR) spectrometry, and Raman spectrometry to shed light on the mechanism of G improvement. Furthermore, one industrial coal blend and the pyrolyzed OSA with a high G (OSA400) were used to perform crucible coking experiments. The coke reactivity (CR) and coke strength after reaction (CSR) indices, thermogravimetric and derivative thermogravimetric curves, pore volumes, and Raman spectra of the resulting cokes were analyzed. The results showed that LTPT significantly increased the G of OSA but there was no benefit in going above 400 °C. the G was modified because of the generation of caking components, the characteristics of which are of medium-sized molecules with suitable molecular structures (e.g., bridge bonds, chain lengths, and functional groups), caused by LTPT. Additionally, the changes in CR and CSR indices between the cokes obtained from the blends with and without OSA400 were within 2.0%, which is acceptable.

Attempts were made to construct the molecular structures of vitrinite samples from four bituminous with different ranks and to investigate the correlation of molecular structures to thermoplastic properties of vitrinite by using a number of advanced analytical techniques combined with theoretical methods. The Gieseler plastometry and caking index showed that the Ewirgol vitrinite had a high fluidity (MF = 17675 ppm), wide plastic range (ΔT = 105.1 °C) and good caking properties (G = 99.32). Various analytical technique, e.g. Solid-state 13C nuclear magnetic resonance spectroscopy, Fourier transform infrared spectroscopy, X-ray diffraction analysis and Raman spectroscopy, provided comprehensive structural information for establishing molecular models of vitrinite samples with Density Functional Theory. These molecular models showed that the Ewirgol vitrinite had more cyclic aliphatic structures that contribute significantly to the fluidity development and caking properties. These cyclic aliphatic structures could be precursors of the aromatic rings in liquid molecules during coking and provide transferable hydrogens that saturate the free radicals in the thermoplastic range. The cyclic aliphatic structures may facilitate the formation of such molecular structures with an appropriate molecule size that maintains the mobile phase in the thermoplastic range to develop fluidity.

Direct coal liquefaction residue (DCLR) was blended with five bituminous coals to prepare crucible coke in the laboratory. A new index liquid-gas ratio (LGR) was defined to quantify relative amounts of liquid phase and gas phase during coking. Great attention was paid to the early stage of coking (400−600 ℃) and then LGR was modified to LGR(t). Relationships and mechanism between LGR, LGR(t) and coke strength were investigated and summarized. Results showed that when high caking property coal ratios was inadequate ( 60 %) and the content of gas druing coking matched the content of metaplast (rational LGR and LGR(t)).