Char Research Articles

Re-examination of the intumescence mechanism of fire retarded PP with APP/pentaerythritol/zeolite-4A using advanced spectroscopic techniques

The mixture of ammonium polyphosphate (APP) and pentaerythritol (PER) is a very efficient flame retardant (FR) intumescent system suitable for polyolefins such as polypropylene (PP). The mechanisms of intumescence of this FR system in this polymer was investigated using different spectroscopic techniques including continuous wave (CW) electron paramagnetic resonance (EPR) spectroscopy and solid state nuclear magnetic resonance (NMR) technique. In this work, the intumescence mechanism of PP/APP/PER formulations with and without 4A is revisited. The intumescent system was in-depth investigated using NMR, CW EPR and pulsed EPR. The CW EPR technique confirmed that free radicals are mainly generated during the intumescence of the system between 250 and 350 °C. Thanks to the pulsed EPR and solid state NMR, it was evidenced that a key structural shift from a predominantly carbonaceous residue to a predominantly phosphorated residue. Besides, it was also evidenced that zeolite 4A totally collapses during extrusion of PP/APP/PER formulations reacting with APP to generate aluminophosphates. Then, silicophosphates are generated between 350 and 400 °C. Both alumino- and silicophosphates contribute to protect aromatic structures in the residue at high temperatures.

Synthesis, Structure, and Actual Applications of Double Metal Cyanide Catalysts.

Double metal cyanide (DMC) complexes represent a unique family of materials with an open framework structure. The main current application of these complexes in chemical industry is their use as catalysts (DMCCs) of the ring-opening polymerization of propylene oxide (PO), yielding branched polyols, highly demanded in production of polyurethanes and surfactants. The actual problem of chemical fixing carbon dioxide from the atmosphere gave new impetus to the development of DMCCs, which turned out to be effective in oxirane/CO2 copolymerization. In recent years, new types and formulations of DMCCs were created, so that greater understanding of the reaction mechanisms was achieved and new fields of catalytic applications were found. In the present review, we summarized background and actual information about the synthesis, structure, and mechanisms of the action of DMCCs, as well as their application in the development of new materials and fine chemicals.

Pyrolysis of Khat waste vs. Coal: Experimental and Aspen plus analysis

This study explores the potential of Khat waste as a biofuel through a detailed analysis of its physical properties and pyrolytic behavior, employing both laboratory and simulation techniques. Biomass, including Khat waste, is a valuable renewable energy source with potential applications in reducing waste and CO2 emissions, especially in rural areas of developing countries like Ethiopia. The physical properties of the Khat waste were thoroughly examined, including moisture content, ash, volatile matter (VM), fixed carbon (FC), and elemental composition. The apparent density of the pyrolyzed khat waste was found to be 0.9688 g/cm³. The TGA results showed a moisture loss of 6.7 %, volatile matter of 4.7 %, fixed carbon of 6.78 %, and ash content of 5.55 %. Notably, Khat waste exhibited unique thermal behavior with a downward shift in TG curves above 220 °C. DTGA identified three decomposition peaks: moisture evaporation at 100 °C, hemicellulose breakdown at 210 °C, and cellulose degradation at higher temperatures. Fourier Transform Infrared Spectroscopy (FTIR) provided insights into the functional groups present in Khat waste, including alkene functional groups and O-H bonds, which are crucial for biofuel properties. Simulation using Aspen Plus software modeled the pyrolysis process, highlighting how varying heating rates affect volatile matter and fixed carbon content. Increasing heating rates decreased volatile matter and moisture but increased fixed carbon content. These findings offer valuable insights for optimizing Khat waste as a biofuel, emphasizing the need for tailored pyrolysis conditions to enhance biofuel production efficiency.

The effects of voltage, particle size, and temperature on bio-oil yield produced via pyrolysis of Sargassum sp

Abstract The energy demand is increasing due to population growth and economic activities. Currently, global energy production, including in Indonesia, heavily relies on fossil fuels like petroleum, which are depleting day by day. One renewable energy form for the future is bio-oil, produced through pyrolysis using biomass as raw material. Macroalgae biomass, particularly Sargassum sp., is a sustainable and net-zero emission source for renewable energy. Pyrolysis is a promising technique to convert Sargassum sp. into high-value charcoal, gas, and bio-oil with less than 20% moisture content. Experimental research was conducted using a simple slow pyrolysis setup, using Sargassum sp. from Pantai Trenggole, Gunung Kidul. Proximate analysis showed Sargassum sp. contains ash, water, volatile matter (Vm), fixed carbon (FC), and calorific value of 15.428%, 6.032%, 40.222%, 38.318%, and 2161.758 cal/g respectively. Regarding the experiment results, the maximum bio-oil yield was obtained at 200 V with a yield of 27.289%. For the particle size variable, the maximum bio-oil yield was achieved with particles of 10-40 mesh, resulting in 27.289% yield. Regarding the temperature variable, the highest bio-oil yield was obtained at 600 °C with a yield of 29.362%.

Hydrothermal carbonization of woody waste: Changes in the physicochemical properties and the structural evolution mechanisms of hydrochar during this process

The Chinese medicine residue (CMR) is composed of wet woody waste, including licorice and ephedra, so using hydrothermal carbonization (HTC) to recover renewable energy from the CMR is a suitable treatment method. An in-depth analysis of the physicochemical properties and structural evolution mechanism of hydrochars is helpful in fundamentally promoting the energy utilization of traditional Chinese medicine waste residue. Therefore, this study analyzed the physicochemical properties and morphological structure of hydrochar produced under varying HTC conditions using multiple testing methods. The evolution of the hydrochar's structural characteristics can be categorized into three stages: component decomposition, structural rearrangement, and carbonization. During the component decomposition and carbonization stages, numerous nanoscale micropores form within the hydrochar. These micropores' specific surface area and pore volume can reach up to 113.420 m2/g and 0.01913 cm3/g, respectively. The highest fractal dimension values for D1 and D2 are 2.6354 and 2.5565, while the maximum values for the microcrystalline stacking height (Lc) and the average number of crystalline layers (Nave) are 0.3354 and 1.9968, respectively. Consequently, the hydrochar produced during these stages exhibits a rougher pore surface and a more complex structure, making it more suitable for adsorbing heavy metals from soil and sequestering CO2. During the structural rearrangement stage, the hydrochar exhibits higher contents of fixed carbon (FC), MgO, P2O5, and a higher C/N atomic ratio, with maximum values of 38.51%, 0.99%, 1.12%, and 28.49, respectively. Thus, the hydrochar produced during this stage is more suitable for soil remediation and nutrient recovery.

A Novel Method for the Enhancement of Sunflower Growth from Animal Bones and Chicken Feathers.

The present study aimed at converting meat industry waste, particularly waste bones and chicken feathers, into biochar to recycle valuable nutrients present in it, which ultimately become part of the municipal waste. The bone biochar (BB) and feathers biochar (FB) were prepared at 550 °C, and their potential was evaluated as an organic amendment for the growth of sunflower. The ash content (AC) and fixed carbon (FC) improved significantly in prepared biochars as compared to raw feedstock. Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDX) analyses signaled the occurrence of various functional groups viz. amide group and hydroxyapatite, porosity, and multiple nutrients. Application of BB and FB in potted soil alone as well as in composites (1:1, 1:2, 2:1) at 1%, 3%, and 5% (w/w) and synthetic fertilizer significantly increased soil pH, electrical conductivity (ECe), organic matter (OM) and water holding capacity (WHC), while reducing the bulk density (BD). The growth of plants grown in soil treated with a 2:1 composite of feathers and bone biochar at 5% application rate showed significantly greater differences in plant height, total chlorophyll content, and plant dry weight than the control but was comparable to growth with chemical fertilizer, rendering it a potential alternative to chemical-based synthetic fertilizer.

Manufacturing processes, additional nutritional value and versatile food applications of fresh microalgae Spirulina.

Spirulina is capable of using light energy and fixing carbon dioxide to synthesize a spectrum of organic substances, including proteins, polysaccharides, and unsaturated fatty acids, making it one of the most coveted food resources for humanity. Conventionally, Spirulina products are formulated into algal powder tablets or capsules. However, the processing and preparation of these products, involving screw pump feeding, extrusion, high-speed automation, and high-temperature dewatering, often result in the rupture of cell filaments, cell fragmentation, and the unfortunate loss of vital nutrients. In contrast, fresh Spirulina, cultivated within a closed photobioreactor and transformed into an edible delight through harvesting, washing, filtering, and sterilizing, presents a refreshing taste and odor. It is gradually earning acceptance as a novel health food among the general public. This review delves into the manufacturing processes of fresh Spirulina, analyzes its nutritional advantages over conventional algal powder, and ultimately prospects the avenues for fresh Spirulina's application in modern food processing. The aim is to provide valuable references for the research and development of new microalgal products and to propel the food applications of microalgae forward.

Surface modification effects on ammonium perchlorate wettability

Solid propellants are commonly used for propulsion systems due to their high volumetric thrust and reliability. Powder bed, binder jetting manufactured propellants will enable unique geometries to be made that are necessary for designers to achieve high thrust levels. However, changes to the particulate wettability from the solvent-based manufacturing technique must be understood such that propellants with adequate mechanical properties are achieved. In this work, the wettability of ammonium perchlorate (AP) crystal surfaces is quantified with solvent and air plasma treatments. Removal of adventitious carbon from AP surface decreases the polybutadiene contact angle from 34 ± 1° to 15 ± 4°. The presence of hydrocarbons from non-polar solvents used in this study with lower vapor pressure was observed to have a similar effect as the adventitious carbon whereas higher vapor pressure solvents have minimal influence on the final wettability of AP surfaces. Polar solvents were determined to alter the surface topology by creating a more hydrophobic surface when compared to the plasma treated samples. An increase in concentration of amine surface groups overcomes the decrease in wettability from carbonaceous residue and surface morphology. The extension and implications of these findings to powder bed, binder jetting manufacturing for propellants is discussed.

A multi-functional coating on cotton fabric to incorporate electro-conductive, anti-bacterial, and flame-retardant properties

Multi-functional textiles have become a growing trend among smart customers who dream of having multiple functionalities in a single product. Thus, this study aimed to develop a multi-functional textile from a common textile substrate like cotton equipped with electrically conductive, anti-bacterial, and flame-retardant properties. Herein, a bunch of compounds from various sources like petro-based poly-aniline (PANI), phosphoric acid (H3PO4), inorganic silver nanoparticles (Ag-NPs), and biomass-sourced fish scale protein (FSP) were used. The coating was prepared via in-situ polymerization of PANI with the cotton substrate, followed by the dipping in AGNPs solution, layer-by-layer deposition of FSP and sodium alginate, and finally, a dip-dry-cure technique after immersing the modified cotton substrate into the H3PO4 and citric acid solution. The key results indicated that the fabric treated with PANI/Ag-NPs/FSP/P-compound exhibited a balanced improvement in all three desired properties as the electrical resistance was reduced by 44.44 % while showing superior bacterial inhibition against gram-positive bacteria (S. aureus) and gram-negative bacteria (E. coli), and produced dense-black carbonaceous char residues, indicating its flame retardant properties as well. Thus, such amicable developments made the cotton textile substrate a multi-functional textile, which showed potential to be used in medical textiles, wearable electronics, fire-fighter suits, etc.

Synthesis of porous carbons for the fixing of cationic molecules in aqueous solution

In Africa, the calyxes of the Hibiscus sabdariffa are widely used to produce a fresh fruit juice, known in Benin as bissap. The stems from this production have no potential use and are therefore an environmental problem. The parietal composition of these stalks revealed a high level of lignin (31 ± 1 %) and cellulose (35 ± 1 %). They can therefore be converted into activated carbon for various applications. In this study, the stems were transformed into activated carbons at moderate temperature using orthophosphoric acid (H3PO4) as the activating agent. The physicochemical, structural, and textural properties were determined. Adsorption kinetics and isotherms were studied and modelled. Porous carbons give specific surface areas equal to 1066 and 1053 m2.g−1 respectively for 2:1 and 4:1 ratios according to the B.E.T-Rouquerol model. Similarly, the said porous carbons give specific surface areas equal to 991 and 975 m2.g−1 respectively for 2:1 and 4:1 ratios according to the 2D-NLDFT model. Using the latter model, the pore size distribution is predominantly microporous, with the Vµ/VT (%) ratio increasing to 56 %. Thermogravimetric analysis of the porous coals showed favourable fixed carbon levels (≈ 60 %). The adsorption kinetics of methylene blue on activated carbons is governed by the pseudo-second order kinetic model indicating that the dye adsorption process is globally controlled by chemisorption. The results of the modelling of the methylene blue adsorption isotherms shown that the Langmuir model is the most credible model that best describes these experimental results, with 588 and 526 mg.g−1. These activated carbons are good candidates for the development of bio-sourced filters for the treatment of industrial wastewater.

Kinetic Modeling of Mass Loss during Carbonization of Sodium Carboxymethyl Cellulose (CMC) Aerogels

The carbonization of sodium carboxymethyl cellulose (CMC) aerogels involves complex thermal decomposition processes leading to the formation of carbonaceous residues. Understanding the kinetics of mass loss during carbonization is vital for optimizing the production of CMC carbon aerogels with desired properties. In this study, a mathematical model is presented that describes the kinetics of mass loss during the carbonization process of CMC aerogels. This model considers the temperature and concentration dependence of CMC decomposition reactions and is validated against experimental data obtained at various conditions. The proposed kinetic model elucidates the underlying mechanisms governing mass loss during carbonization, offering valuable insights for the design and optimization of CMC carbon aerogels across diverse applications. Furthermore, the analysis of the experimental data reveals variations in both the reaction order and the rate constant for different concentrations of CMC aerogels, indicating distinct kinetic behavior. These findings contribute to a deeper understanding of the carbonization process and pave the way for tailored synthesis approaches to meet specific application requirements.

Waterproof flexible strain sensors with high sensitivity for detecting human movement, airflow size and water ripples prepared by demulsification

Carbon nanotubes (CNTs) have found extensive applications as conductive fillers in the fabrication of flexible strain sensors; however, their propensity to agglutinate often leads to non-uniform distribution within flexible matrix. In this study, we propose a method of demulsifying while adsorbing and fixing carbon nanotubes to prepare a conductive composite based on polyacrylic resin and carbon nanotube with uniform dispersion. Due to its distinctive surface structure, the flexible strain sensor based on this conductive composite exhibits simultaneous positive and negative strain effects, resulting in exceptional sensitivity (ranging from 4.86 to 140.68), ultra-high detection limit (13 mg), and long durability (stretched 12,000 times and compressed 10,000 times). This sensor can be used for detecting small strains such as airflow and pulses as well as larger stresses such as various joint movements in human physiological activities. Meanwhile, the sensor exhibits exceptional waterproof performance, enabling its suitability for water-related sensor detection tasks such as monitoring water wave oscillations and measuring the rotational speed of water. Furthermore, due to its high conductivity properties, this conductive composite material can also be utilized for Joule heating.

Syringaldehyde‐DOPO derivative for enhancing flame retardancy and mechanical properties of epoxy resin

AbstractWith the wide application of epoxy resins in adhesives, electronic packaging materials, and aerospace fields, it is necessary to prepare high‐performance flame‐retardant epoxy resins to reduce the fire risk caused by their flammability. In this study, the rigid structure intermediate Schiff base (DMDA‐SH) was synthesized by condensation reaction of syringaldehyde (SH) with O‐Tolidine (DMDA). Then, DMDA‐SH‐DOPO, a novel P/N‐structured biobased flame‐retardant curing agent, was synthesized by addition reaction with 9,10‐dihydro‐9‐oxaza‐10‐phosphame‐10‐oxide (DOPO) and was applied to the preparation of intrinsic flame‐retardant epoxy resin. As expected, DMDA‐SH‐DOPO has good flame‐retardant properties due to the synergistic action of N/P elements. Epoxy resin with only 2.5% DMDA‐SH‐DOPO (P = 0.16%) can pass the UL‐94 V‐0 test. Compared with DGEBA/DDM, DMDA‐SH‐DOPO‐7.5's (P = 0.49%) peak heat release rate was reduced by 48.4% and the limiting oxygen index (LOI) reached 27%, making it a flame‐retardant material. From the point of view of carbonaceous residue performance, the expansion height of carbon residue after DMDA‐SH‐DOPO‐7.5 combustion is significantly increased, and the amount of carbon residue at 800°C is increased by 36.4%. In addition, appropriate DMDA‐SH‐DOPO can effectively improve the bending property of epoxy resin. This study provides a new idea for preparing renewable high‐performance intrinsic flame‐retardant epoxy resin.

From sewage sludge and lignocellulose to hydrochar by co-hydrothermal carbonization: Mechanism and combustion characteristics

This investigation focuses on fabrication of hydrothermal carbon (HTC) using the co-hydrothermal carbonization (Co-HTC) method from the raw materials of sewage sludge (SS) and lignocellulose. The as-prepared hydrochar (HC) was characterized and analyzed by using ultimate analysis, proximate analysis, scanning electron microscopy (SEM), Brunauer-Emmett-Teller (BET) analysis, and Fourier transform infrared spectroscopy (FTIR) to investigate its fuel properties, surface morphology, and molecular structure. Particularly, the HC obtained from the Co-HTC process with pine sawdust as raw material exhibited several advantages in terms of carbon content (40.40 %), fixed carbon (FC) content (41.82 %), and high heating value (HHV, 14.87 MJ/kg). Synergistic effects were achieved from the components in the Co-HTC system, leading to increased carbon content, retention of organics, energy yield, HHV, and HC yield. Notably, the Co-HTC treatment of pine sawdust and SS demonstrated the most notable synergistic effect. Thermogravimetric analysis and combustion characteristic index (CCI) values showed that softwood lignin, represented by pine sawdust, exhibited better performance during combustion, with a CCI value of 21.78 (10−7 min−2 °C−3). In short, Co-HTC of hydrochar from lignocellulose and SS can represent a promising approach to resource utilization for obtaining solid fuel.

Raman spectroscopy of Ryugu particles and their extracted residues: Fluorescence background characteristics and similarities to CI chondrites

AbstractWe present here an investigation of Ryugu particles recovered by the Hayabusa2 space mission and their extracted carbonaceous acid residues using Raman spectroscopy. Raman parameters of Ryugu intact grains and their acid residues are characterized by broad D (defect induced) and G (graphite) band widths, indicating the presence of polyaromatic carbonaceous matter with low thermal maturity. Raman spectra of Ryugu particles and CI (type 1) chondrites exhibit stronger laser‐induced fluorescence backgrounds compared to Type 2 and Type 3 carbonaceous chondrites. The high fluorescence signatures and wide bandwidths of the D and G bands of Ryugu intact grains are similar to the Raman spectra observed in CI chondrites, reflecting the low structural order of their aromatic carbonaceous matter, and strengthening the link between Ryugu particles and CI chondrites. The high fluorescence background intensity of the Ryugu particles is due to multiple causes, but it is likely that the relative abundance of geometry‐bearing macromolecular organic matter in total organic carbon contents makes a large contribution to the fluorescence intensities. Locally observed high fluorescence in the acid‐extracted residues of Ryugu is due to nitrogen‐bearing outlier phase. The high fluorescence signature is one consequence of the low degree of thermal maturity of the organic matter and supports evidence that the Ryugu particles have escaped significant parent body thermal metamorphism.

Influence of Carbon Material Properties on Slag‐Foaming Dynamics in Electric Arc Furnaces: A Review

In this article, the impact of conventional carbon sources, alongside potential carbon bio‐sources, on slag‐foaming behavior is investigated. It highlights the complex relationship between these carbon sources and their properties, such as fixed carbon (FC), volatile matters (VMs), mineral composition in ash, reactivity, and wetting, which ultimately influence the slag foaming efficiency. The challenges associated with biochar and the significant differences in foaming behavior are addressed. For biochar to achieve effective slag foaming, it is essential that it contains an FC of at least 60 wt% and ash of less than 5 wt%. Though less impactful than CO generation from iron (II) oxide reduction, VMs from carbon sources, especially with high‐VM biochar, show secondary effects on reaction courses. The disadvantages associated with the high reactivity of biochar can be overcome by improving its physicomechanical and physicochemical properties. Despite the potential of biochar–coke mixtures to benefit slag foaming without enhancing biochar properties directly, challenges such as biochar floatation on the liquid slag surface and rapid burn‐off exist. Biocoke offers foaming results comparable to those of conventional sources. Despite the benefits of biocoke over other carbon sources, the review underscores its relatively unexplored status in the context of slag‐foaming applications.

Spark plasma sintering of SiC-based bulk materials from carbonaceous residue of rice husk thermal processing

Relevance. The search for a useful application of carbonaceous residues of rice husks thermal processing. These residues due to high silicon content in the inorganic part can potentially be used to produce silicon carbide – an important functional material for various fields of science and technology. Useful utilization of this waste will allow not only solving the environmental problem associated with their inefficient application and formal disposal, but also obtaining value-added products in the form of SiC-based ceramics. Aim. To obtain SiC-based bulk products from carbonaceous residues of rice husk thermal processing by spark plasma sintering with a minimum number of additional stages of feedstock processing. Objects. SiC-based bulk products obtained using carbonaceous residues of rice husk thermal processing. The samples were obtained by spark plasma sintering at 1800 °C, pressure of 60 MPa and holding time of 10 minutes. Methods. Spark plasma sintering; X-ray diffractometry (X-ray phase analysis); scanning electron microscopy; vacuumless arc discharge synthesis method. Results. The authors have carried out the experimental studies to assess the possibility of applying carbonaceous residue of rice husk thermal processing as a precursor for the synthesis of silicon carbide in bulk (ceramics) and dispersed (powder) forms. A series of experiments on spark plasma sintering of carbonaceous residue from rice husk thermal processing in the initial and milled form, with SiO2 silica sand additives, as well as with the use of silicon carbide powders synthesized from carbonaceous residue by vacuumless arc discharge method were implemented. The latter is performed within a one-stage fast-flowing process in an air environment and does not require the use of a vacuum system. Preliminary results demonstrated the possibility of obtaining bulk products and dispersed powders based on silicon carbide with a content of at least 50 and 60 wt %, respectively, and indicate the prospects of further increasing phase purity by optimizing spark plasma sintering and vacuumless arc discharge synthesis.

Fire behavior of furfurylated paulownia wood

ABSTRACT Wood is an aesthetically pleasing, sustainable material for various uses. All materials, including wood, are intended to be long-lasting, maintaining their original appearance. The effects of furfurylation on the fire characteristics of wood are still unclear, even though it significantly increases the dimensional stability, hardness, and biodegradation resistance of wood. This study aimed to evaluate the fire characteristics of furfurylated wood. Thermogravimetric analysis showed that the time required for the infiltration of furfuryl alcohol into the samples significantly exceeded the values commonly reported in the literature. The results obtained by measurements on a cone calorimeter indicate that furfurylation significantly increases peak values of heat release rate, carbon monoxide, carbon dioxide, and smoke production in the phase immediately after the initiation. On the contrary, carbon-monoxide (CO) production decreased in the phase of heterogeneous combustion of carbonaceous residue.

Evolution and correlation of the physiochemical properties of bamboo char under successive pyrolysis process

This study investigated the effects of bamboo age, bamboo parts, and pyrolysis temperatures on the physiochemical properties of bamboo char throughout a series of pyrolysis processes spanning from 150 °C to 1000 °C. The results indicated that as the pyrolysis temperature increased from 150 °C to 500 °C, the yield of bamboo char experienced a rapid decline, settling at a maximum of 69%, with no significant impact from bamboo age and parts. Subsequently, as the pyrolysis temperature continued to rise from 500 °C to 1000 °C, the yield stabilized at 25.74–32.64%. Besides, fixed carbon (FC), volatile matter (VM), and ash content were temperature-dependent, while the H/C, O/C, (N + O)/C, and aromatic index kept constant after reaching 500 °C. Notably, 800 °C was confirmed to be a crucial turning point for physiochemical properties, at which the graphitic structural changes occurred, pore collapsed, and potassium salts released. Bamboo age was proved to enhance the stability. Pearson correlation coefficient (PCC) analysis revealed that the pyrolysis temperature was positively correlated (p < 0.01) with ash (0.76), FC (0.97), AI (0.81), R50 (0.77), and C–C/C = C/C–H (0.87). Conversely, negative correlations (p < 0.01) were observed with VM (−0.91), O/C (0.88), H/C (−0.95), (N + O)/C (−0.87), C loss (−0.79), and labile organic-C (−0.78). Additionally, bamboo age was negatively correlated (p < 0.01) with C loss (−0.40), volatile organic-C (−0.63), labile organic-C (−0.45), and recalcitrant organic-C (−0.40), but positively associated with R50 (0.54), refractory organic-C (0.42), and inorganic-C (0.52). Bamboo parts did not exhibit significant correlations with char properties.Graphical

THERMAL PROCESSING OF OIL FLAX BONES INTO ACTIVATED CARBON

Flax shives – waste generated during the primary processing of flax in the textile industry, make up 70% of the total mass of oil flax stalks. The results of an experimental study of the thermal processing of oil flax bonfires by the method of slow conductive pyrolysis in the temperature range of 400–650 °C are presented. An experimental bench for thermal decomposition of flax fire and activation of carbon residue by superheated water vapor is presented. The required temperature regimes of pyrogenetic decomposition were established, which are in the range of 500–600 °C. An analysis of the physicochemical properties of experimental samples of biochar obtained by pyrogenetic decomposition of flax fires has been carried out. At low temperatures of 400–430 °C, the specific gravity of carbon is in the range of 80–82%. Under temperature conditions of 500–600 °C, the specific gravity of carbon was 91–93%. At higher temperature conditions, the yield of gaseous products increases, and the ash content in the solid carbonaceous residue increases. The modes of steam activation of biochar from flax fires have been established, so to achieve the best sorption values, water vapor should be at a temperature of 900 °C. A comparative analysis of the sorption abilities of experimentally obtained activated carbon with BAU-A activated carbon is given. Based on the data obtained, it was concluded that the activated carbon from the fire of flax corresponds to the parameters of GOST 6217-74.