Combustion Tests Research Articles

Thermal Characteristics Enhancement of AN/Mg/NC Composite Using Activated Carbon/Cobalt Oxide as Highly Effective Catalytic Additive

Our study examined the potential of using activated carbon/nanosized cobalt oxide (AC-Co3O4) as a new catalytic additive to improve the efficiency of the parent ammonium nitrate/magnesium/nitrocellulose (AN/Mg/NC) composite. These findings demonstrate a significant improvement in the thermal characteristics of AN/Mg/NC/AC-Co3O4 compared to the initial AN/Mg/NC. Raman spectra confirmed the multilayered nature of AC. Fourier-transform infrared spectroscopy (FTIR) analysis confirmed the presence of cobalt oxide in the synthesized additive. Differential scanning calorimetry (DSC) revealed the catalytic effect of AC-Co3O4 on the AN/Mg/NC composite, resulting in the reduction in the decomposition peak temperature (Tmax) from 277.4 °C (for AN/Mg/NC) to 215.2 °C (for AN/Mg/NC/AC-Co3O4). Thermal gravimetric analysis (TG) determined the overall mass losses (%) for AN/Mg/NC (70%), AN/Mg/NC/AC (75%), and AN/Mg/NC/AC-Co3O4 (80%). This analysis highlights the significant role of AC-Co3O4 in enhancing the energy release during decomposition. Moreover, the use of the differential thermogravimetric (DTG) technique demonstrated the two-step decomposition pathways attributed to the multi-component system. Finally, the combustion tests under the pressure of 3.5 MPa validated the catalytic efficiency of the AC-Co3O4 additive, which enhanced the burning rate (rb) of the AN/Mg/NC/AC-Co3O4 composite from 10.29 to 19.84 mm/s compared to the initial AN/Mg/NC composite. The advantageous nature of the AN/Mg/NC/AC-Co3O4 composite with a lowered decomposition temperature can be applied in rocket propulsion systems, where the precise control of combustion and ignition processes is crucial.

The synergistic flame retardant effect of biobased phytic acid arginine salt and hydroxylated montmorillonite in polybutylenes succinate

In this research, hydroxylated nano montmorillonite (DK2) was used as a synergistic agent in combination with phytic acid arginine salt (PaArg). The flame retardancy and mechanical properties of PBS with different amounts of PaArg and DK2 were studied. Furthermore, the synergistic effect and mechanism of PaArg and DK2 in PBS were explored. The results showed that adding 23.5 % PaArg and 1.5 % DK2 increased the limiting oxygen index value (LOI) of the composite to 31.4 %, passing the UL 94 V-0 rating. By adding 25 % PaArg alone, the LOI value of the composite is 26.2 %, and the vertical burning test result is only V-2 rating. The cone calorimetry test results show that the peak heat release rate, total heat release rate, and total smoke production of PBS/23.5 % PaArg/1.5 % DK2 composite are 55.8 %, 17.1 %, and 44.7 % lower than those of PBS/25 % PaArg composite, respectively. All the results showed that PaArg and DK2 exhibited good synergistic flame retardancy in PBS. In addition, the impact strength and bending strength test results show that the impact strength and bending strength of PBS/23.5 %PaArg/1.5 %DK2 composite are higher than those of PBS/25%PaArg composite. This work improved the flame retardant efficiency of biobased flame retardants in PBS.

Combined treatment of wood with thermosetting resins and phosphorous flame retardants

Wood modification with thermosetting resins results in improved dimensional stability and durability. However, the treatment does not enhance fire resistance. To address this, Scots pine sapwood (Pinus sylvestris L.) was impregnated with thermosetting resins such as 1,3-dimethylol-4,5-dihydroxyethyleneurea, phenol-formaldehyde resin and melamine-formaldehyde resin, along with a phosphorus polyol as the flame retardant. Both weight percent gain and cell wall bulking were measured to investigate the deposition of resin and phosphorus polyol. Fire resistance was assessed through thermogravimetric analysis, Bunsen burner test and mass loss calorimeter. The inclusion of a phosphate polyol improved thermal stability, reduced flammability and heat release. Melamine-formaldehyde resin combined with phosphorus polyol demonstrated self-extinguishing capability with the heat release rate comparable to non-combustible materials inside 400 s. Moreover, the total heat release within 600 s shows an 84% reduction compared to untreated wood.

Toughened and reinforced the petroleum-based epoxy resin via thermotropic liquid crystal bio-based counterpart

Significant improvements in the fracture resistance of epoxy resins are highly desirable for various applications, but there is a “seesaw” between toughness and other properties. In this study, we incorporated a bio-based thermotropic liquid crystal epoxy precursor (THMT-EP) containing multi-aromatic s-triazine structure derived from vanillin into petroleum-based counterpart tetraglycidyl-4,4′-methylene dianiline (TGDDM) with 4,4-diaminodiphenyl sulfone (DDS) as a curing agent, and the cured co-blended resin system was able to immobilize the formed liquid crystal domains in a cross-linked network under optimal curing conditions. The blended system with THMT-EP added at 30 wt% exhibited the largest impact strength (31.1 kJ m−2), which was 90.8 % higher than pristine TGDDM/DDS epoxy resin. When THMT-EP was added at 50 wt%, the flexural modulus and strength of the blended system were as high as 4016 MPa and 171.5 MPa, respectively, which were 5.1 % and 48.5 % higher than those of the TGDDM/DDS system, and the resultant was able to pass the highest V-0 level of vertical combustion test. The above results show that it is feasible to improve the performance of petroleum-based epoxy resins with bio-based thermotropic liquid crystal counterpart.

Analysis of the pyrolysis process of ionic liquid-based flame retardant rigid polyurethane foam

In this study, flame retardant polyurethane rigid foam was prepared by incorporating 15 wt% ammonium polyphosphate (APP) and ionic liquid (1-butyl-2,3-dimethylimidazolium tetrafluoroborate, abbreviated as B4F). The flame retardant and thermal stability of the material were evaluated using vertical combustion (UL-94), limiting oxygen index (LOI), cone calorimeter (CONE), and thermogravimetric analyzer (TG) tests. Additionally, scanning electron microscopy (SEM), Raman spectroscopy (Raman), and X-ray photoelectron spectroscopy (XPS) were utilized to explore the flame retardancy mechanism in the carbon layer after combustion. The experimental results showed that the addition of 1 wt%B4F and 14 wt% APP to the polyurethane (RPUF/14APP/1B4F) significantly improved the vertical combustion test, upgrading it from the V-1 level to the V-0 level. This improvement was attributed to the increased degree of graphitization of the material, as evidenced by the reduced ratio of amorphous carbon to graphitic carbon (ID/IG) from 2.68 to 1.38. XPS analysis revealed that RPUF/14APP/1B4F exhibited a higher C/O ratio in the residual carbon (3.03) compared to RPUF/15APP (1.84), indicating that B4F effectively enhanced the antioxidant properties of the flame-retardant materials. Under the air atmosphere, RPUF/14APP/1B4F demonstrated an increased char formation at 800 °C (21.24 %), which was 71.01 % higher than RPUF/15APP. The interaction between B4F and APP led to the formation of a more stable char layer structure in polyurethane, further enhancing its flame retardancy. In conclusion, the RPUF/14APP/1B4F demonstrated a synergistic flame retardancy effect and enhanced thermal stability. The addition of B4F improved the graphitization degree of the material and increased the C/O ratio in the residual carbon, enhancing the antioxidant properties of the system. Moreover, the interaction between B4F and APP promoted the formation of a more stable char layer, effectively improving the flame retardant properties of the polyurethane. These findings provide valuable insights for the development of advanced flame retardant polyurethane materials with improved fire safety in various applications.

Thermal decomposition and charring behavior of polyphenylene sulfide/para-amrid fiber composite paper with excellent fireproof property

A charring behavior was found during the combustion of para-aramid chopped fibers/polyphenylene sulfide (ACFs/PPS) composite paper, which formed a highly graphitized carbon layer structure with specific mechanical properties. This sturdy structure is composed of a dense carbon layer mixed evenly between the inner and outer layers, the outer layer can effectively block the spread of oxygen and degradation products, as well as external heat radiation, while safeguarding the inner layer's structural integrity. Herein, we systematically researched the flame retardancy and thermal degradation properties of ACFs/PPS composite paper. In combustion testing, the char of ACFs/PPS composite paper could support a weight of 50 g, while the neat aramid paper was burned through by fire, which indicates the Charcoal-forming property of ACFs/PPS composite paper is better than that of neat aramid paper, and ACFs/PPS composite paper has better fire resistance because of its good char formation. Meanwhile, we further showcase the application in electrically insulating and firefighting clothing interlayers.

A multi‐element flame retardant for rail transit to improve the flame retardant performance of epoxy resin while reducing smoke density

AbstractA P/N/Si structure flame retardant DTBD was successfully synthesized by 3,5‐diaminobenzoic acid, 9,10‐dihydro‐9‐oxa‐10‐phosphaphenanthrene‐10‐oxide (DOPO), triphenylsilanol, and benzaldehyde. The chemical structure of DTBD was analyzed by Fourier transform infrared (FTIR) and nuclear magnetic resonance (NMR) spectra, which showed that DTBD was successfully synthesized. By analyzing the curing behavior, the addition of DTBD promoted the curing of epoxy resin (EP). According to the limited oxygen index (LOI) and UL‐94 vertical combustion tests, it can be shown that the introduction of DTBD makes the epoxy resin have good self‐extinguishing properties. Py‐GC/MS analysis showed that the phosphorus free radicals and ammonia generated in the gas phase of DTBD could quench and dilute by capturing reactive free radicals and refractory gases. DTBD could improve the tensile and flexural properties of epoxy resin. According to the European flame retardant standard EN45545‐2, the Ds of EP‐15 and EP‐20 obtained HL1 grade. With the increase in DTBD content, the VOF4 of modified EP also gradually decreased, and both EP‐15 and EP‐20 obtained HL2 grade.

Flame-retardant smoke-suppressing and antibacterial poplar wood enabled by a bio-based flame retardant containing transition metal

Utilizing bio-based flame retardants like chitosan (CS) and tannic acid (TA) is an effective way to enhance the flame retardancy of wooden products. In this work, the poplar wood was impregnated with composite flame retardants containing CS, TA, Cu (CH3COO)2·H2O and silane coupling agent (KH550). When KH550 bound these substances together to form a stable compound, a highly efficient flame-retardant wood (wood/CTA-Cu-Si) was prepared under vacuum pressure impregnation. The results of the functional group test show that bio-based flame retardants have been successfully synthesized. The limiting oxygen index (LOI) of the treated sample was reached 31.5%, the sample also passed the V-0 grade in the UL-94 vertical burning test, and in the Cone colorimeter test, the total smoke release was reduced by 50.2% compared to that of the Control. The energy dispersive spectroscopy proved that Cu and Si elements were evenly distributed in the wood before and after combustion. Raman spectra of the residues after the burning of treated wood were compared and it was found that the degree of graphitization of wood/CTA-Cu-Si was significantly increased, which ID/IG reached 1.85. After impregnation, the flame-retardant treated wood sample exhibited no negative effect on mechanical properties. The flame-retardant mechanism was probed and summarized as the Cu and Si synergistic promotion on charring and suppression on heat and smoke release. Simultaneously, the existences of Si-C, Si-O and Si-N strengthened the char layer and enhanced flame retardancy of poplar wood. Such resulted poplar wood with flame retardancy will be an excellent application prospect as engineering biomaterial.

Intelligent bamboo: A splendid flame retardant, fire warning and photothermal sterilization nanocoating via low-temperature evaporation induced self-assembly

The application of bamboo to assist carbon neutral strategy has attracted worldwide attention due to its naturally carbon-negative property. However, the inherent defects of flammable and mildewed make bamboo encounter a bottleneck in its application. Hence, an intelligent bamboo (IB) with integrated performances of stable connection, high-temperature resistance, reliable fire warning and splendid photothermal sterilization properties was constructed via low-temperature evaporation induced self-assembly strategy. The hydrogen bonding, coordination complexes, van der Waals forces, and electrostatic forces can be formed between Ti3C2Tx (MXene) and pre-treated bamboo substrate (TB). The optimized bamboo-based fire alarm sensor (AM@TB) exhibits significant improvement in flame retardant properties, e.g., the limiting oxygen index (LOI) value of AM@TB8-2 was 61.4%, surpassing TB by an impressive margin of 65.8% and the vertical burning test reach the UL94 V-0 rating. Besides the PHRR (heat release rate) of AM@TB8-2 was decreased 80.3% compared to TB. The residual mass of AM@TB8-2 is 34.5%, which is 1.6 times higher than TB. Additionally, the AM@TB8-2 presents a sensitive fire warning response (∼2 s) and reliable repeatability. Furthermore, based on the outstanding photothermal conversion performance of MXene, AM@TB8-2 demonstrates predominant sterilization efficacy after a near-infrared laser (NIRL) illumination. Therefore, this work provides inspiration for the design and fabrication of high-performance IB that combine fire safety and antimicrobial properties.

Flame‐retardant composite derived from polyurethane/wood‐fiber

AbstractWood–plastic composites (WPCs) are facing fire hazard when they are used in construction and furniture and need to be treated with fire protection. In this work, polyurethane (PU) was applied to derive simultaneously flame‐retardancy‐improved and mechanically strengthened wood‐polyurethane composites (WPUCs). It was constructed with ammonium polyphosphate (APP) and PU by a simple way. The results showed that a decrease in smoke production in the Cone Calorimeter Test was measured. When the mass of APP is 18% of PU, limiting oxygen index can reach 31.2%. In the combustion test, the peak of heat release rate and total smoke production for WPUCs were, respectively, decreased by 42.1% and 89.7% in the presence of the above ratio of APP and PU. In addition, the results of the functional group test show that PU contains highly reactive ‐NCO which is bonded to the ‐OH and moisture in the wood fiber, resulting in improvement of physical and mechanical properties. The mechanism for the flame retardancy of WPUCs revealed that polyphosphoric acid produced by APP pyrolysis catalyzed PU into the char, and PU was arched by the resulting gases such as NH3 to form the tiny spherical structure, which worked in blocking heat and the exchange of substances. WPUCs with APP prepared by this method are shown to have improved results, and, therefore, it is expected to provide a new strategy for the preparation of flame‐retardant WPCs.

A thermostable phosphorus/nitrogen-based flame retardant with enhanced compatibility with PET

Poly(ethylene terephthalate) (PET) presents a persistent challenge in achieving satisfactory fire safety while maintaining its melt spinnability primarily due to its poor compatibility with flame retardants (FRs). In this study, the issue was effectively addressed through the application of suitable phosphorus/nitrogen (P/N)-based FRs (PBPO), which can form strong hydrogen bonding with PET and have a close melting temperature (Tm) to PET. As a result, the prepared PET/PBPO composites showed high fire safety and good melt spinnability simultaneously. Specifically, PET/PBPO6 (containing 6 wt% of PBPO in PET) exhibited a peak heat release rate (PHRR) over 30 % lower than that of pure PET, and was found to be non-ignitable with only one molten droplet generated during the vertical burning test, achieving the UL 94 V-0 level. Significantly, PET/PBPO6 filaments, which were prepared by melt spinning the PET/PBPO6, showed pleasing tensile properties and were self-extinguished within 3 s.

Flammability and Soil Burial Performance of Sugar Palm (Arenga pinnata (wurmb) merr) Fiber Reinforced Epoxy Composites

This study investigates the effects of soil burial and flammability on sugar palm fibre (SPF) (Arenga pinnata (wurmb) merr)-reinforced epoxy composites. In order to determine the flammability and biodegradability properties, experiments are conducted in accordance with ASTM standards. The hand lay-up method was used to fabricate composite samples with two different weight ratios between epoxy and SPF, which were 70:30 and 50:50. Biodegradability and flammability properties were investigated using horizontal burning tests, limiting oxygen index (LOI), cone calorimetry, and soil burial. It was found that the Epoxy/SPF-50 was the composite that exhibited the fastest degradability at 0.81%/week. The result of the horizontal burning test showed that the addition of SPF reduced the burning rate but slightly increased it at 50 wt% because the ratio between epoxy and SPF exceeds the optimum fibre loading. The Epoxy/SPF-50 exhibited a better LOI value at 23.3 than pure epoxy (control), which was 19.8. From the cone calorimetry test, it was observed that the time to ignition (TTI) and total heat release (THR) values were decreased when the amount of SPF increased. Char production increases the flame-retardant protection of SPF-reinforced epoxy composites. To the best of the authors’ knowledge, no published study has been conducted on the flammability and biodegradability characteristics of SPF-reinforced epoxy composites.

Innovative Air Bypass System for Low-Emission Multi-Can Combustors

Abstract Gas turbines that are used as compressor drives are often operated in the part load regime because compressor stations are usually designed for operation with full power at extreme weather conditions. Consequently, these gas turbines must comply with strict emission regulations at unfavorably low turbine inlet temperatures. To extend the low-emission operation range of the premixed combustion systems, many gas turbines bypass a part of the compressed air upstream of the combustor and either blow it off into the exhaust stack or reinject it into the secondary combustion zone. This study presents a new approach that overcomes shortcomings by injecting the compressed air in the burner head in the vicinity of the primary combustion zone. This is particularly attractive for multi-can combustors. Atmospheric combustion tests are conducted for two different air injection designs. The first design features lower air injection velocity and the second features higher injection velocities. Both injection strategies are tested with the industrial MGT gas turbine can combustor. The full size burner is tested at atmospheric conditions in a burner test rig with a quartz flame tube and natural gas as fuel. The performance of the air bypass system is assessed by means of CO and NOx emission measurements for different air bypass ratios. Additionally, OH* chemiluminescence camera pictures are presented and compared to numerical calculations. It is found that the air injection in the annular vicinity of the swirl flame does not cause increased CO emissions by quenching or other effects.

Experiment Study and Industrial Application of Slotted Bluff-Body Burner Applied to Deep Peak Regulation

During the deep peak shaving period, the boiler needs to operate at a lower load, so higher requirements were set for the boiler's stable combustion. In order to better evaluate and compare the stable ignition capacity of bluff-body burners and slotted bluff-body burners, guidance and calculation support for the design of boiler deep peak shaving were needed. This study adopted the reflux heating chain ignition analysis method to study the differences in the steady combustion mechanism between the bluff-body burner and the slotted bluff-body burner. A thermal combustion experiment was conducted in employing the single angle coal powder combustion furnace. The experimental results were compared against the theoretical analysis results. In addition, a study was conducted on the application of slotted bluff-body burners in the deep peak shaving of a 330MW unit power plant boiler. The results showed that as long as the small slot flow can catch fire, the mixed temperature of the reflux fluid of the slotted bluff-body burner will be higher than that of the bluff body burner. This will enhance its steady combustion ability. The combustion test results were found to be consistent with the analysis results, indicating that when the slotted bluff-body burner is used on the 330MW unit, the boiler combustion is in good condition. In this case, it has a stable combustion capacity of 66MW (20% economic continuous rating) without oil injection at low loads. This study revealed the advantages of the slotted bluff-body burner in terms of its steady combustion mechanism compared to traditional bluff-body burners. It verified the feasibility for boiler deep peak shaving in practical applications. This is of great significance for improving the flexibility of coal-fired power generation units, enhancing the flexibility of the power system, and promoting carbon reduction.

Synthesis, characterization and performance evaluation of a flame retardant plasticizer for poly(vinyl chloride) derived from biobased vanillic acid

The utilization of biobased resources presents a novel approach for the development of high-performance plasticizers with exceptional flexibility. Nevertheless, the combustibility of flexible poly(vinyl chloride) (PVC) products containing high content plasticizers is frequently disregarded. The development of PVC functional plasticizers requires careful consideration of a good balance between flame retardancy, migration resistance and plasticity through molecular structure design. Currently there is a dearth of biobased plasticizers that exhibit exceptional comprehensive properties. Therefore, a novel biobased flame-retardant plasticizer (VA8-P) has been synthesized from vanillic acid and fully characterized using NMR, IR and MS. The VA8-P plasticized PVC exhibits a lower glass transition temperature and higher low temperature resistance, while its elongation at break is 1141.6% higher than unmodified PVC. Transmittance, haze, cross-sectional SEM and 2D/3D AFM all demonstrate its good optical properties and the compatibility of the plasticizer with polymer matrix. PVC plasticized using VA8-P exhibits better hydrophilicity and especially superior migration resistance than does the same polymer plasticized using DOP. The thermal stability and char residue rate for decomposition of VA8-P plasticized PVC are better than the same parameter of material plasticized with DOP. In cone calorimeter tests, VA8-P plasticized PVC showed excellent heat barrier effect. Additionally, PVC-P3 reached the UL-94 VTM-0 level in the vertical burning test. Its flame-retardant mode of action was also verified by TGA–FTIR analysis. A functional biobased plasticizer with excellent comprehensive properties has been synthesized. This material exhibits greater flexibility than many traditional flame-retardant additives and its use can be expected to improve the fire resistance of flexible PVC.

Investigation on the Performance of Fire and Smoke Suppressing Asphalt Materials for Tunnels

The volatilization of asphalt fumes not only affects the health of construction workers, but also damages the environment. It even affects the construction quality of asphalt pavement in tunnels. This article focuses on solving the emission of asphalt fumes to better protect human health and the environment, while satisfying the use of asphalt pavement. A flame retardant and smoke suppressant (compound) with Mg(OH)2 as the main component was developed, and flame retardant asphalt mixture and asphalt mastics were prepared to evaluate the flame retardant and smoke suppressant properties and performance effects. Firstly, its low- and high-temperature performances were investigated with BBR and DSR, respectively. Then, the indoor combustion test and the cone calorimeter test were used to evaluate the fire retardant smoke suppression effect of the asphalt mastic. Thirdly, the flame retardant effect of asphalt mastic mixed with the compound was further analyzed by the TG test and SEM. The pyrolysis temperature, mass loss, and microscopic state of the asphalt surface were used to verify and explain the flame retardant reaction effect and process of the compound. Finally, the asphalt mixture performance was evaluated, as well as the flame retardant smoke suppression effect by asphalt mixture combustion tests. The results showed that the flame retardant smoke suppression time of the flame retardant asphalt mixture was reduced by 66%, and the smoke emission area was reduced by 20%. The flame retardant smoke suppression effect of the asphalt mixture was improved by 44%. It is proven that this kind of fire retardant and smoke suppressing asphalt mastic and mixture met performance needs in use, and the fire retardant and smoke suppressing effect was obvious. This solution addresses the issue of asphalt smoke generated during the construction of asphalt pavement, providing better support for the construction of asphalt pavement in tunnels.

Eco-friendly flame retardant coating based on ammonium polyphosphate and tyramine for lyocell fabrics

Low-carbon emissions are a sustainable development approach, among which lyocell is a renewable and zero carbon biodegradable cellulose fiber. The flammability of lyocell fabric poses a threat to people's lives and property. In response to this issue, a bio-based flame retardant, tyramine polyphosphate (APP-LA), was synthesized and applied to the treatment of lyocell fabrics. The synthesis of APP-LA adopted an eco-friendly and organic solvent-free method. In the combustion test, the limiting oxygen index of APP-LA treated lyocell fabrics increased to 35.8% compared to control lyocell (18.5%), and the damage length was only 6.7 cm. Meanwhile, the peak heat release rate and total heat release decreased by 92.9% and 58.7% respectively, compared to the control lyocell. Besides, the P-containing compounds generated by APP-LA accelerated the decomposition of the matrix to produce a dense char layer. The fewer flammable volatiles and more non-flammable gases were released. This work provided a low-cost and eco-friendly strategy for the simple preparation of commercial flame-retardant lyocell fabrics.

Combustion of chicken manure and Turkish lignite mixtures in a circulating fluidized bed

Burning chicken manure (CM) with lignites may be a promising method to ensure waste management. In this study, a circulating fluidized bed boiler (CFBB) system was designed, manufactured, and tested for the disposal of CM in poultry farming. Combustion and co-combustion tests of CM and Kale Lignite (L) were carried out in the CFBB to determine the effect of excess air ratio and CM share in the fuel mixture on combustion efficiency and flue gas emissions. As the CM share in the mixture increased, the combustion efficiency increased from 86 % to 95 %. It was observed that while CO emissions increased, SO2 and NOx emissions decreased with respect to CM share. CO emissions ranged from 726 to 2241 mg/Nm3 for 100%L and between 838 and 2450 mg/Nm3 for 100%CM. The NOx emissions changed between 177.5 and 240 mg/Nm3 for 100%CM; however, it was 276.3 mg/Nm3 for 100%L. While SO2 emissions (average) for 100%L were around 5200 mg/Nm3, as the CM share in the fuel mixture increased, emissions decreased, and when they became zero for 100%CM. CO emissions decreased as the excess air ratio increased. SO2 and NOx emissions increased as the excess air ratio increased in almost all fuel mixtures. This combustion system was proposed for waste disposal, emission reduction, and usage of domestic sources. Photovoltaic panels can support this system and meet farms' operational energy requirements away from the grid. Combustion efficiency can be increased by operating the system at oxy-firing mode instead of air-firing.

Flame-Retardant and Smoke-Suppression Properties of Bamboo Scrimber Coated with Hexagonal Boron Nitride

In order to improve the flame-retardant properties of bamboo scrimber, chitosan (CS) and polyvinyl alcohol (PVA) were used as the film-forming substances, and hexagonal boron nitride (h-BN) was used as the flame-retardant substance to prepare h-BN flame-retardant coatings, which were coated on the surface of the bamboo scrimber. The effects of the h-BN flame-retardant coatings with different quality concentrations on the flame-retardant properties of the bamboo scrimber, as well as on the morphology of the residual carbon, were investigated using the analytical methods of FTIR, environmental scanning electron microscopy, thermogravimetric analysis, combustion test, and coating adhesion test. The results showed that the h-BN flame-retardant coating could improve the thermal stability of the bamboo scrimber and that the higher the mass concentration, the better the thermal stability of the h-BN. Compared to the control, the time to ignition (TTI) of the 5% h-BN flame-retardant-treated specimens increased by 56%; the peak heat release rate (Pk-HRR), total heat release (THR), and total smoke production (TSP) decreased by 9.92%, 7.54%, and 32.35%, respectively; however, due to the presence of PVA, the peak smoke production rate (Pk-SPR) increased by 17.78%. The 5% h-BN coating had very good adhesion, with an adhesion grade of zero. In conclusion, the h-BN coating could be well-adhered to the surface of the bamboo scrimber, and the 5% h-BN flame-retardant coating had a better flame retardancy compared to other treatments, meaning that it could provide a new strategy for improving the flame-retardant properties of bamboo scrimber for construction use.

Machine learning-enabled rational design of organic flame retardants for enhanced fire safety of epoxy resin composites

This study proposed an approach utilizing machine learning (ML) to accelerate the design of organic flame retardants (FRs) for epoxy resins (EPs), avoiding the limitations of traditional trial-and-error methods. For the first time, ML models have been established and considered for five pivotal parameters: limiting oxygen index (LOI), peak heat release rate (PHRR), total heat release (THR), time to ignition (TTI), and vertical combustion test (UL-94) level. These models were employed to consider and assess the significance and relevance of FRs structure and addition amount to the essential flame retardancy of EPs. The ML models showed excellent performance, with the coefficient of determination scores around 0.8 for the test set. Utilizing key structural insights gleaned from these ML models, a FR referred to as BDOPO was employed here to experimentally verify the changes in the properties of EP composites loaded with different amounts of BDOPO (EP/BDOPO), and the results showed that, except for the TTI, the ML models could accurately predict all the other properties of EP/BDOPO. The study also elucidated the flame retardancy mechanism of BDOPO in EP. This approach provides an effective method for designing organic FRs for high-performance EP.