Fired Plants Research Articles

1 dead, 2 injured in KMCO plant fire

An explosion and fire at the KMCO chemical plant in Crosby, Texas, killed one worker, James Earl “Bubba” Mangum, and critically injured two others on April 2. The specialty chemical manufacturer makes products for automotive, petroleum, industrial, and agricultural markets. Accident information was scant as of C&EN deadline, but the fire was thought to have been caused by a leaking transfer hose that released flammable isobutylene. The isobutylene ignited and the fire spread to tanks holding ethanol and a warehouse, said Rachel Moreno, a spokesperson for the Harris County Fire Marshal’s Office. The community within a 1.6 km radius of the plant was ordered to shelter in place for several hours until the fire was put out. As of C&EN deadline, investigators had been unable to enter the plant, which is located near Houston, to determine the exact cause of the incident, Moreno said. Likewise, investigators had still been unable

Soot morphology and nanostructure in complex flame flow patterns via secondary particle surface growth

While the majority of studies explore soot formation in relatively simple, one-dimensional flames, most real-world flames consist of complex flows defined by large-scale turbulent eddies, recirculating flow patterns, and buoyancy effects. The effects of complex flow on soot physicochemical properties are poorly understood. This work employs an inverted gravity flame reactor (IGFR) to compare differences in soot growth between a one-dimensional laminar diffusion flame and a recirculating flame. Computational fluid dynamics (CFD) and experimental observations show particle oscillations between (i) a rich region with a high concentration of surface growth species, and (ii) a high-temperature oxidation region. Transmission electron microscopy (TEM) shows a significant difference in final primary particle diameter, where the one-dimensional flame produces primary particles 10–25 nm in diameter and the recirculating flame produces primary particles 25–75 nm in diameter. Additionally, larger primary particles from the recirculating flame contain both single and multiple cores. We propose that due to the spheroidal shape of the large primary particles, the secondary surface growth is primarily a result of polyaromatic hydrocarbon (PAH) condensation during re-entrainment of mature soot into the fuel-rich region followed by subsequent liquid layer carbonization in the high-temperature environment of the flame front. The recirculating flow patterns in the IGFR and repeated particle growth/oxidation cycle can serve as a model for soot formation in the large-scale flames with complex flow patterns, such as forest fires, coal fire plants, and other sources.

Effects of pulverized coal particle size on flame structure in a methane-assisted swirl burner

The effects of the particle sizes of pulverized coal on the flame structure in a coal fire plant were studied experimentally. This study mainly focused on the inner recirculation zone (IRZ) and exhaust tube vortex (ETV), which are major parameters for a reduction of NOx in swirl-stabilized pulverized coal combustion. To clarify the effects of the coal particle size, three different sized Glencore particles were prepared, namely, under 90 µm (GC90↓), under 150 µm (GC150↓), and between 90 and 150 µm (GC90–150). The temperature of the coal particles, the intensity of the OH chemiluminescence, and the pulverized coal flame structure were compared with the particle sizes of pulverized coal. In a pulverized coal flame, the temperature and OH radical intensity were shown to decrease with an increase in the coal particle size, and the IRZ and ETV increase with a decrease in the particle size. The residence time of the coal particles increase in the IRZ and ETV, which creates a reduction environment and a fuel-rich condition, leading to a reduction of NOx emissions.

Authentication in cloud-driven IoT-based big data environment: Survey and outlook

Abstract The Internet of Things (IoT) is composed of different networked objects (i.e., smart devices) which are interconnected to gather, process, refine, and exchange meaningful data over the Internet. These objects are assigned to their respective IP addresses, and they are able to send and receive data over a network without any human assistance. IoT offers different types of applications, such as, but not limited to, smart traffic monitoring, smart home, smart health care and smart cities, to name a few. In a Cyber-Physical System (CPS), computing elements coordinate and communicate with sensor devices, which monitor cyber and physical indicators, and actuators, and also modify the cyber and physical environment where they run. The synergy of computational as well as physical components, specifically the use of CPSs, led to the advancement of IoT implementations. In a cloud-driven IoT-based big data environment, a cloud-based platform is used to store the data generated by IoT devices (normally by sensor devices) which further can be considered as a big data warehouse. This environment is highly scalable and provides important real-time event processing (for example, in critical scenarios like surveillance and monitoring of an industrial plant). In IoT-based critical applications, the real-time data access is obligatory as and when it is required. Such access is possible if we permit only authorized external users to access the real-time data directly from the IoT sensors. Sometimes authorized user may also request for big data query processing and big data analytics over the data stored in cloud servers to figure out hidden patterns of some phenomena (i.e., chances of fire in an industrial plant in future). Therefore, we need secure authentication schemes for cloud-driven IoT-based big data environment in which a legitimate user and an IoT sensor can mutually authenticate each other and establish a common session key for secure communication. In this context, this paper first discusses the network and threat models of the authentication schemes for cloud-driven IoT-based big data environment. Some security requirements, issues and challenges of this environment are then discussed. A taxonomy of various existing authentication schemes applicable for cloud-driven IoT-based big data environment is also discussed, which covers a comparative study of these schemes. We identify and briefly discuss some future research challenges in designing the authentication schemes and other security protocols for cloud-driven IoT-based big data environment that need to be addressed in the future.

Increased seasonality and aridity drove the C4 plant expansion in Central Asia since the Miocene–Pliocene boundary

Continuous and high-resolution records of the content, mass accumulation rate (MAR) and δ13C values of black carbon obtained from Integrated Ocean Drilling Program (IODP) Site U1430 in the southwestern Japan Sea have been established and combined with previous results obtained from Central Asia. The main objective of this work is to reconstruct the historical changes in vegetation types (C3–C4), and to constrain the driving force of C4 plant expansion over the last 13 Ma. The stable carbon isotope value of black carbon (δ13CBC) shows a major shift since the Miocene–Pliocene boundary (∼5.3 Ma), suggesting significant expansion of C4 plants in broad areas of Central Asia, including the inland basins of northwestern China and the Loess Plateau. However, a decline in the content and MAR of black carbon reveals the absence of any link between fire and C4 plant expansion in Central Asia, due to the dramatic decrease in biomass under a drying regime. On a global scale, asynchronous expansion of C4 plants suggests that regional hydroclimatic change, rather than decline in CO2 concentration, was the most important factor to influence C4 expansion. We propose that the increased seasonality and the enhanced long-term aridity driven by the concurrent decline in winter westerly vapor, and increase in East Asian summer monsoon precipitation, were the main driving forces of C4 plant expansion in broad areas of Central Asia. Variations in winter westerly moisture have played a significant role in changes of regional climate and vegetation in Central Asia since the late Miocene.

Alternative stable equilibria and critical thresholds created by fire regimes and plant responses in a fire‐prone community

Wildfire is a dominant disturbance in many ecosystems, and fire frequency and intensity are being altered as climates change. Through effects on mortality and regeneration, fire affects plant community composition, species richness, and carbon cycling. In some regions, changes to fire regimes could result in critical, non‐reversible transitions from forest to non‐forested states. For example, the Klamath ecoregion (northwest United States) supports extensive conifer forests that are initially replaced by hardwood chaparral following high‐severity fire, but eventually return to conifer forest during the fire‐free periods. Climate change alters both the fire regime and post‐fire recovery dynamics, potentially causing shrubland to persist as a stable (i.e. self‐renewing) vegetation stage, rather than an ephemeral stage. Here, we present a theoretical investigation of how changes in plant traits and fire regimes can alter the stability of communities in forest‐shrub systems such as the Klamath. Our model captures the key characteristics of the system, including life‐stage‐specific responses to disturbance and asymmetrical competitive interactions. We assess vegetation stability via invasion analysis, and conclude that portions of the landscape that are currently forested also can be stable as shrubland. We identify parameter thresholds where community equilibria change from stable to unstable, and show how these thresholds may shift in response to changes in life‐history or environmental parameters. For instance, conifer maturation rates are expected to decrease as aridity increases under climate change, and our model shows that this reduction decreases the fire frequencies at which forests become unstable. Increases in fire activity sufficient to destabilize forest communities are likely to occur in more arid future climates. If widespread, this would result in reduced carbon stocks and a positive feedback to climate change. Changes in stability may be altered by management practices.

ANALYSIS OF LAYOUT SOLUTIONS OF ELECTROLYSIS SHOP OF HYDROGEN SUPERSTRUCTURE TAKING INTO ACCOUNT THE RELIABILITY AND EXPLOSION RISK

The article considers the layout solutions of the electrolysis shop of the hydrogen superstructure outside the territory of the nuclear power plant. To do this, an annual risk assessment was carried out taking into account the reliability and explosion risk for 1-4, 8 and 16 separate electrolysis shops installed on the site of the hydrogen superstructure. When taking into account equipment breakdowns, with possible explosions and fires in electrolysis plants, the risk due to fires and explosions was several times lower than the risk associated with equipment failures. Calculations showed that the transfer of electrolysis plants to increased hydrogen productivity in the event of failure of one of the cells is the best option in comparison with the reduction in the generation of electricity at the steam turbine installation of the hydrogen superstructure.

Dripping Behavior of Wire Fire under Varying Pressure and Electric Current

Dripping of polymer insulations is a different type of hazardous behaviors in wire fire, which has a potential risk of igniting adjacent combustible material and causing the dramatic growth and spread of fire in buildings, aircraft, spacecraft and nuclear power plant. To improve the fire-safety strategy, bench scale tests are conducted to study the dripping phenomenon using thin wire sample under various atmosphere pressure and electric current. The results show that the variation of flame front has a slight fluctuation during molten dripping, while the flame size (especially flame height) changes significantly. Moreover, dripping frequency (f) decreases with pressure (Ρ) due to a sufficient burning effect, but it increases with electric current (Ι) because of a stronger accumulating effect.

Climate–fire interactions constrain potential woody plant cover and stature in North American Great Plains grasslands

AbstractAimDisturbances such as fire operate against a backdrop of constraints imposed by climate and soils to influence grass–woody plant abundance. However, little is known of how these factors interact to determine the upper limits of woody cover and stature in grasslands, in which shrub/tree abundance has been increasing globally.LocationKansas, Oklahoma, Texas, USA.Time period2004–2014.Major taxa studiedAngiosperms and gymnosperms.MethodsUsing a database of 1,466 sites and quantile regression to derive precipitation‐based upper limits to woody cover and height within grasslands of the central/southern Great Plains, USA, we assessed how soil texture and climate‐related fire probabilities [two groups; low fire probability, P(Flow), versus high fire probability, P(Fhi)] might influence realization of the climate potential.ResultsSoil texture had no substantive influence on regional‐scale woody cover, but taller plants were predicted on sandy soils. Woody plant height potential increased linearly with increasing annual precipitation, becoming asymptotic at c. 800 mm for both the P(Flow) and the P(Fhi) fire groups, after which P(Flow) areas were predicted to support taller plants. Potential woody cover also increased linearly with annual precipitation until c. 800 mm, after which predictions of maximum % cover were similar under both fire groups.Main conclusionsPrecipitation was the overriding factor constraining potential woody cover and height, particularly in drier regions, with fire playing a minor role at these regional scales. In contrast to height potential, cover potential remained similar for both P(Flow) and P(Fhi) sites. Dynamic adjustments in woody plant architecture and allocation to foliage and stems, wherein areal cover is maintained when height is suppressed has implications for remote sensing, primary production and biogeochemical processes. Our analyses indicate drier grasslands [< 800 mm mean annual precipitation (MAP)] undergoing woody plant encroachment have the potential to become shrublands (e.g. short woody plants, low cover), whereas wetter areas have the potential to become woodland or forest (taller woody plants, high cover).

Global change and the importance of fire for the ecology and evolution of insects.

Climate change is drastically altering global fire regimes, which may affect the structure and function of insect communities. Insect responses to fire are strongly tied to fire history, plant responses, and changes in species interactions. Many insects already possess adaptive traits to survive fire or benefit from post-fire resources, which may result in community composition shifting toward habitat and dietary generalists as well as species with high dispersal abilities. However, predicting community-level resilience of insects is inherently challenging due to the high degree of spatiotemporal and historical heterogeneity of fires, diversity of insect life histories, and potential interactions with other global change drivers. Future work should incorporate experimental approaches that specifically consider spatiotemporal variability and regional fire history in order to integrate eco-evolutionary processes in understanding insect responses to fire.

Seasonal Timing of Fire Alters Biomass and Species Composition of Northern Mixed Prairie

Fire plays a central role in influencing ecosystem patterns and processes. However, documentation of fire seasonality and plant community response is limited in semiarid grasslands. We evaluated aboveground biomass, cover, and frequency response to summer, fall, and spring fires and no fire on silty and clayey sites in semiarid, C3-dominated grassland. The magnitude of change in biomass between years was greater than any differences among fire treatments. Still, differences existed among seasons of fire. Summer fire reduced non-native annual forb frequency (3% vs. 10% ± 2%) and Hesperostipa comata, reduced native annual forbs the first year, increased Poa secunda and bare ground, and increased Vulpia octoflora the second year. Fall fire increased grass biomass (1224 vs. 1058 ± 56 kg∙ha−1), but fall fire effects were generally similar to those of summer fire. Spring fire effects tended to be intermediate between no fire and summer and fall fire with the exception that spring fire was most detrimental to H. comata the first growing season and did not increase bare ground. All seasons of fire reduced litter, forb biomass, and frequency of Bromus japonicus and Artemisia spp., and they reduced H. comata, V. octoflora, and native annual forbs the first year, but increased basal cover of C3 perennial grasses (2.2% vs. 0.6% ± 0.4%). Fire during any season increased dominance of native species compared with no fire (6.6% vs. 2.0% ± 1.0% basal cover) and maintained productivity. Seasonal timing of fire manipulated species composition, but increased C3 perennial grass cover and native species dominance with fire during any season indicated that using fire was more important than the season in which it occurred. In addition, fire effects on the vegetation components tended to be counter to previously observed effects of grazing, suggesting fire and grazing may be complementary.

Microepidemic of fibreglass dermatitis after a thermoelectric power plant fire explosion.

Microepidemic of fibreglass dermatitis after a thermoelectric power plant fire explosion.

An emergency decision making method based on the multiplicative consistency of probabilistic linguistic preference relations

As the evolution of emergencies is often uncertain, it may lead to multiple emergency scenarios. According to the characteristics of emergency management, this paper proposes an emergency decision support method by using the probabilistic linguistic preference relations (PLPRs) whose elements are the pairwise comparisons of alternatives given by the decision-makers (DMs) in the form of probabilistic linguistic term sets (PLTSs). As the decision data are limited, it is difficult for the DMs to provide exact occurrence probabilities of all possible emergency scenarios. Thus, we propose a probability correction method by using the computer-aided tool named the case-based reasoning (CBR) to obtain more accurate and reasonable occurrence probabilities of the probabilistic linguistic elements (PLEs). Then, we introduce a multiplicative consistency index to judge whether a PLPR is consistent or not. Afterwards, an acceptable multiplicative consistency-based emergency decision support method is proposed to get more reliable results. Furthermore, a case study about the emergency decision making in a petrochemical plant fire accident is conducted to illustrate the proposed method. Finally, some comparative analyses are performed to demonstrate the feasibility and effectiveness of the proposed method.

An improved model for estimating heat release rate in horizontal cable tray fires in open space

Electric cable fires in nuclear power plants could be disastrous and have to be studied carefully for safety and economic considerations. Based on the results of previous work on large-scale and bench-scale cable fire testing, the Flame Spread over Horizontal Cable Trays model was modified and improved to estimate the heat release rate of large-scale cable fires using bench-scale measured data. The heat release rate per unit area measured in the cone calorimeter experiment is taken as the input, to avoid introducing any prediction uncertainties caused by inconsistent values of the heat of combustion and char yield of the cable. Cable fire experiments with vertical stacks of trays with one to three layers of cables were conducted in open space to assess the accuracy of the improved model. In comparing with the experimental results, predictions using the improved model are encouraging. The local error of prediction is less than 15% and the global error lies between 19.2% and 35.7%. In addition, three cable tray fire experiments with data available in the literature were used to validate the improved model. It is shown that the improved model had good predictions for these cable tray fires.

Comparative study on the construction of support system initiating event fault trees for a fire probabilistic safety assessment

This study compared two different fire-induced support system initiating event fault tree (SSIE FT) models: one with only fire IE initiators, and the other with both fire IE initiators and enabling events. Enabling events place a system in a state such that it transitions from the operating state to the failed state when the initiating event occurs. To develop the fire event probabilistic safety assessment (PSA) models for these two different SSIE FT models, hypothetical internal event accident scenarios were used based on the assumption that a fire included in the fire event PSA causes a reactor shutdown. The results obtained indicate that SSIE FT models with only fire IE initiators, in terms of quantification results of fire event PSA models, are equivalent to those with both fire IE initiators and enabling events under the assumption that a fire included in the fire event PSA results in a reactor shutdown. For the case where a fire in a nuclear power plant (NPP) does not lead to a reactor shutdown, on the other hand, this study showed that SSIE FT models with only fire IE initiators might underestimate the real fire-induced risk, whereas SSIE FT models with both fire IE initiators and enabling events could lead to reasonable quantification results for risk due to fires.

Florida wildfires during the Holocene Climatic Optimum (9000–5000 cal yr BP)

Fire is a key ecological driver in terrestrial ecosystems of the southeastern United States. The combination of plant species composition and fire poses the possibility of positive feedback loops in a landscape. How fire regimes will change in the future with global warming is uncertain. To better understand the main factors that control fire, Holocene fire history was studied using macroscopic charcoal (as a fire proxy) in sediment cores from two shallow lakes in north Florida, USA. Following the onset of lacustrine sedimentation in the early Holocene, there was a 95% decline in average charcoal concentration, from 28.3 to 1.4 charcoal particles cm−3, at ~ 7500 cal yr BP in a 3.9-m core from Newnans Lake (basal age: 8870 cal yr BP). At ~ 7000 cal yr BP in a 5.4-m core from nearby Lochloosa Lake (basal age: 9280 cal yr BP), particle density declined by 99%, from 113.8 to 1.4 charcoal particles cm−3. These declines in charcoal concentration are not artifacts of changes in bulk sedimentation, i.e. dilution, but instead reflect lower charcoal production. Newnans Lake and Lochloosa Lake averaged ~ 8.93 and ~ 40.42 charcoal particles cm−3, respectively over their entire records. Pollen records from the two study lakes do not display the Quercus to Pinus shift during the Holocene Climatic Optimum (9000–5000 cal yr BP) observed previously in cores from many studied lakes in the region. Instead, pine pollen, as a percentage of total oak and pine pollen, was high (> 50%) through the entire Holocene. Pine and oak pollen counts and the variety of arboreal pollen, however, were lower in early Holocene deposits. No relation was found between pine and oak percentages and macroscopic charcoal quantity, i.e. before, during, or after charcoal peaks. There were, however, qualitative differences between pollen assemblages within charcoal-rich and charcoal-poor depth intervals. Early to middle Holocene sediments contained pollen of Quercus spp., Pinus spp., Ambrosia sp., Amaranthaceae, Cyperaceae and Poaceae. Late Holocene sediments contained hydric and mesic pollen types including Taxodium spp., Carya sp., Ilex sp., and Liquidambar styraciflua. The flat, poorly drained topography around both lakes played a role in shaping Holocene plant communities and probably explains why a Quercus-to-Pinus shift seen elsewhere in Florida did not occur in the study region.

New potential bacterial antagonists for the biocontrol of fire blight disease (Erwinia amylovora) in Morocco

The effectiveness of antagonistic bacteria to control Erwinia amylovora was evaluated under in vitro and field conditions. Among 61 bacteria isolated from soil and flowers of fire blight host plants of different Moroccan areas, 20 bacterial isolates showed higher antagonistic activity against the pathogen during agar-diffusion-test, attached blossoms assay and in a bioassay on immature pear fruits. Effective isolates were identified by using biochemical tests and 16 S rRNA genes sequencing. These isolates were grouped into the following genera: Alcaligenes (ACBC1), Pantoea (ACBC2, ACBP1, and ACBP2), Serratia (HC4), Brevibacterium (SF3, SF4, SF7, and SF15), Pseudomonas (SP9), and Bacillus (CPa12, CPa2, HF6, JB2, LMR2, SF14, SF16, SP10, SP13, and SP18). Furthermore, isolates were reported in the NCBI nucleotide sequence database (Genbank) under the accession numbers from KY357285 to KY357304. A 2-year field trials consisted of spray treatments with different bacterial antagonists was conducted on the susceptible apple cultivars ‘Gala’, ‘Golden Parsi’ and ‘Golden Smoothee’. Their efficacies were evaluated 15 days post-inoculation on detached blossoms and were ranged from 54.6 to 95.0% for 11 strains, most of them were slightly better or better than that obtained with commercial bacterial strains P10c (66%) and QST713 (63%). In field trials, the most effective were P. agglomerans ACBP2, B. amyloliquefaciens LMR2, B. halotolerans (SF3 and SF4), and B. mojarvensis SF16. In addition, effective bacterial isolates did not show the pathogenicity signs towards plant tissue and are, therefore, considered as potential candidates to be integrated in actives ingredients of microbial formulation for the effective control of Fire Blight.

Growth-Form Responses to Fire in Nama-Karoo Escarpment Grassland, South Africa

Fire is a rare phenomenon in the semi-arid Nama-Karoo region of South Africa, but appears to have become more common in recent years, possibly as a result of climate change. The ecological effects of fire in this vegetation are poorly understood, but are likely to involve changes in structural composition, that of the shrub-grass ratio in particular. A fire burned an area of Karoo escarpment grassland (a mixture of shrubs and grasses) on the Nuweveld Mountains in October 2013. We assessed changes in plant structural composition and fire survival or persistence strategies of perennial shrubs at 2.5 years post fire. The canopy cover abundance of grasses, herbs, and dwarf shrubs increased post fire, while that of large shrubs decreased. Despite all large shrub species (except Elytropappus rhinocerotis [L.f.] Less.) exhibiting post-fire resprouting and reseeding, vigor varied widely within species. Localized post-fire extinctions appeared possible in many large shrub species, including Cliffortia arborea Marloth (Vulnerable; Raimondo et al.2015). Increases in fire frequency or fire intensity are predicted to result in persistent negative feedbacks (the grass-fire cycle) whereby the herbaceous stratum would increase in dominance at the expense of larger woody growth forms. This process may be hindered by actions to prevent and suppress fires.

Effects of fire regime on plant species richness and composition differ among forest, woodland and heath vegetation

AbstractQuestionDo the effects of fire regimes on plant species richness and composition differ among floristically similar vegetation types?LocationBooderee National Park, south‐eastern Australia.MethodsWe completed floristic surveys of 87 sites in Sydney Coastal dry sclerophyll vegetation, where fire history records have been maintained for over 55 years. We tested for associations between different aspects of the recent fire history and plant species richness and composition, and whether these relationships were consistent among structurally defined forest, woodland and heath vegetation types.ResultsThe relationship between fire regime variables and plant species richness and composition differed among vegetation types, despite the three vegetation types having similar species pools. Fire frequency was positively related to species richness in woodland, negatively related to species richness in heath, and unrelated to species richness in forest. These different relationships were explained by differences in the associations between fire history and species traits among vegetation types. The negative relationship between fire frequency and species richness in heath vegetation was underpinned by reduced occurrence of resprouting species at high fire frequency sites (more than four fires in 55 years). However, in forest and woodland vegetation, resprouting species were not negatively associated with fire frequency.ConclusionsWe hypothesize that differing relationships among vegetation types were underpinned by differences in fire behaviour, and/or biotic and abiotic conditions, leading to differences in plant species mortality and post‐fire recovery among vegetation types. Our findings suggest that even when there is a high proportion of shared species between vegetation types, fires can have very different effects on vegetation communities, depending on the structural vegetation type. Both research and management of fire regimes may therefore benefit from considering vegetation types as separate management units.

Integrated assessment of safety distances for rescue work in chemical plant fires involving domino effects

This study employed the Suite for the Assessment of Flammable, Explosive, and Toxic Impacts to synergize the environmental data, risk frequency, and physical and chemical properties of chemical‐induced fires and explosions at accident sites and thereby establish an integrated assessment model. In addition, the suite was used to visualize fires and explosions resulting from domino effects caused by thermal radiation and blast overpressure in initial accidents at chemical plants.The simulation results were successfully utilized to respond to a chemical plant fire, assist the fire command officer to determine the range of domino effects during rescue, and extinguish the ignition source. In addition, the model provided safety distances for rescue to enable the proper deployment of rescuers and vehicles and to prevent their exposure to deadly hazards.The simulation results also provided the integrated safety distances including acceptable safety distances for rescuers with the appropriate protective equipment and the range of domino effect during the first accident and the second accident. © 2017 American Institute of Chemical Engineers Process Saf Prog 37: 186–193, 2018