Pyrolysis and Combustion Characteristics of Extruded Polystyrene

Organic thermal insulation materials (OTIMs) play a vital role in building energy conservation, while they pose significant fire hazards due to their high flammability, leading to numerous fire incidents. To assess their fire risk, this study investigated the combustion characteristics of expanded polystyrene (EPS), extruded polystyrene (XPS) and polyurethane (PU) using cone calorimeter experiments and the entropy method. Key parameters, including heat release rate (HRR), total heat release (THR), smoke production rate, total smoke production (TSP), CO and CO2 production rates, O2 consumption rate, typical time, theoretical critical heat flux (CHF), ignition temperature (T ig ), fire performance index (FPI) and fire growth index (FGI), were systematically evaluated and compared. The results showed that heat flux significantly affected the combustion characteristics of EPS and PU. At 35 kW/m2, EPS exhibited delayed ignition, whereas PU failed to combust completely. Despite having the lowest peak HRR value, PU yielded the highest THR value. Among the materials, XPS produced the most total smoke, while PU showed the highest CO generation rate but the lowest CO₂ yield and O₂ consumption. PU also demonstrated the shortest ignition time and the lowest CHF and T ig , indicating its higher flammability. In contrast, EPS exhibited the longest ignition time. Fire performance analysis revealed that XPS had the lowest FPI value and the highest FGI value. The entropy-based fire risk assessment ranked the materials as PU (0.50) > XPS (0.45) > EPS (0.12), confirming PU as the most hazardous, followed by XPS and EPS.

The pyrolysis model in Fire Dynamics Simulator version 6.1.2 is applied to numerically describe the decomposition and burning behaviour of two materials (wood and plastic) used to construct pallets as the fuel load in a large-scale tunnel fire experiment. The kinetic parameters for the wood and plastic are derived from thermogravimetric analyser experiments using genetic algorithm multiple-component scheme, hand calculation multiple-component scheme and genetic algorithm one-component scheme. The kinetic parameters along with other related thermal properties are used to simulate a series of cone calorimeter experiments. Results from these simulations found that the use of the different component schemes has a significant influence on the decomposition and burning behaviour predictions in Fire Dynamics Simulator version 6.1.2. However, irrespective of the component scheme, the burning behaviour prediction of the solids is also dependent on the thermal property settings. The predictions of the heat release rate curves are not always comparable to the cone calorimeter experimental curves under different external heat fluxes when a consistent set of thermal properties is used. The best results are obtained at incident heat fluxes of 35 kW/m2 for the plastic samples and 25 kW/m2 for the wood samples such that these are sufficient to enable simulation of the large-scale tunnel fire experiment in future work.

Thermal and oxidative decomposition of bitumen at the Microscale: Kinetic inverse modelling

Low temperature oxidation Air injection has the advantages of low energy consumption and low environmental pollution, and is an important means of heavy oil development. In order to study the change characteristics of heavy oil in Ji 7 well area of Xinjiang oilfield and the feasibility of air injection for oil displacement, dynamic oil displacement experiments were carried out by using one-dimensional combustion tube. The heat release and heavy oil characteristics of Ji 7 heavy oil at different ignition temperatures were studied. Thermogravimetric analysis and differential scanning calorimetry experiments were carried out by using TG/DSC thermal analyzer, combined with component analysis and thermal component analysis. The exothermic law and reaction mechanism of low temperature oxidation of Ji 7 heavy oil at different temperatures were analyzed by analytical kinetics analysis method. The feasibility of low temperature oxidation flooding technology by air injection was evaluated according to the reservoir characteristics. The results show that the oxidation of Ji 7 heavy oil can be divided into three stages: low temperature oxidation (LTO), fuel deposition (FD) and high temperature oxidation (HTO). Weak self-exothermic phenomena can be detected after oxidation of Ji 7 heavy oil at 40 ~C. After oxidation at 180 ~C, the combustion and deposition stage of Ji 7 heavy oil has obvious characteristics, the low temperature oxidation stage weakens, the high temperature oxidation stage migrates to the direction of lower temperature, DTG and DSC peaks. The value is more obvious, and the peak value of mass loss and heat flux is larger. Under reservoir temperature and pressure conditions, the oxidation of heavy oil and air is weak. After oxidation and pressurization of Ji 7 heavy oil, the thermal effect of low temperature oxidation of heavy oil is remarkable. It is suggested that pressurization start air injection development at higher initial temperature (about 350 C).KeywordsAir injectionLow temperature oxidationHeavy oilThermal analysisJi 7 well area

As the construction of high-rise buildings increases to solve residential spaces caused by high density population concentration, the occurrence of fire accidents in high-rise buildings is also increasing. The primary cause of fire damage in high-rise buildings is the spread of fire caused by exterior wall finishes. Therefore, it is essential to develop semi-non-combustible finishes that can be applied to high-rise buildings to prevent the spread of fire due to exterior wall finishes. To address this issue, numerous studies are being conducted to develop flame retardant finishing materials that reduce heat release rate and total heat release. A double flame retardant mixed waste paper with expandable graphite and magnesium hydroxide was manufactured to improve the fire performance of cellulose building finishing materials. Total heat release (THR), CO, and CO2 Generation changes were measured using a cone calorimeter, and thermal diffusion rate was measured through the LFA 1000 experiment. The correlation of total heat release, CO generation, CO2 generation, and mass reduction rate by variation of expandable graphite's mesh size at double flame-retardant waste paper were secured through a cone calorimeter test. The thermal diffusion rate data of the specimen were secured through the LFA 1000 experiment. Through experiments, it has been confirmed that specimens using specific expandable graphite particles can be utilized as fire-resistant finishing materials in construction, ensuring fire resistance performance.

Pyrolysis behavior and product distribution of exinite submacerals

The heterogeneous catalytic ignition of lean to stoichiometric n-butane/air mixtures were studied at various total pressures between 10 and 100 kPa and at temperatures equal to or larger than the critical ignition temperatures. The induction periods, ignition and extinction temperatures were measured under strict isothermal conditions. The discussion presented in this paper is based on several literature models. The data analysis allowed for the determination of the overall kinetic parameters. The rigorous isothermal conditions indicated that the extinction temperatures are lower than the ignition, a behavior different from the results obtained in stagnation-point flow reactors.

Flame retardant flexible polyurethane foams from novel DOPO-phosphonamidate additives

Investigation of EPET, EPEI, and EPU pyrolysis characteristics: Thermal decomposition behaviours, pyrolysis products and mechanism

Fire safety is the most critical aspect of high-rise building safety. As human life is essential than other aspects, analysis of a reliable building fire safety performance is more critical than ever. Whenever an actual fire incident occurs, the active firefighting systems in the building would be activated first. As a result, it is necessary to identify the operation of active firefighting systems as well as proper service and maintenance of the systems. The research problem was identified as, people tend to fulfill the minimum fire safety requirements imposed by regulations. Therefore, the condition of fire safety performance in most highrise buildings are very poor. The aim of this research is to identify suggestions to improve the fire safety performance in high-rise buildings in Sri Lanka. Consequently, three objectives have been established to fulfill the research aim. In the first objective, building design features, human behaviors, equipment failures, and underperformance of fire regulations are highlighted as contributing factors to building fire events. The second objective evaluates fire safety precautions implemented in high-rise buildings, such as alarm activation, communication and evacuation procedures, service and maintenance periods of live fire systems, and fire evacuation drills. In the third objective, suggestions to improve the fire safety performance in high-rise buildings are recognized as, maintaining proper coordination between the fire brigade and building fire maintenance department at all times. Since the interpretivism philosophy used in this inductive qualitative research, the data was collected through conducting ten interviews with professionals who are primarily engaged with achieving reliable fire safety performance in high-rise buildings. In conclusion, recommendations such as, establish a coordination center to maintain proper coordination with fire brigade, air force and building maintenance staff and introduce a trained air force squad with helicopters and firefighting equipments can be implemented in Sri Lankan high-rise buildings. KEYWORDS: fire safety, high-rise buildings, construction

Evaluation of the thermal stability and pyrolysis mechanism of 1-ethyl-3-methylimidazolium dicyanamide and 1-Butyl-3-methylimidazolium dicyanamide by STA, DSC, TG-FTIR

Application of genetic algorithms and thermogravimetry to determine the kinetics of polyurethane foam in smoldering combustion

Study on pyrolysis process and mechanism of organic coating of waste polyesterimide enameled wire based on density functional theory

Effect of accelerated weathering on pyrolysis kinetics and ignition characteristics of typical thermal insulation materials

Kinetic reaction mechanism of lignocellulosic biomass oxidative pyrolysis based on combined kinetics