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This paper determines the optimal surfactant concentration for enhancing coal's wettability and explores the wetting mechanism at surfactant concentrations above the critical micelle concentration (CMC) during coal seam water injection. In this study, laboratory experiments and field tests were used to investigate the influence of monomeric surfactants and compound surfactants at various concentrations on coal's wettability. The results showed that when the surfactant solution concentration was greater than the CMC, the coal's wettability was significantly enhanced as the surfactant concentration increased. However, the coal's wettability did not monotonically increase with the concentration, and the maximum value was reached in the range of 0.5-3 wt.%. Increasing the surfactant adsorption density and changing the adsorption state on the coal surface were the essential reasons surfactants continued improving the coal's wettability at concentrations above the CMC. The Marangoni flow effect and changes in the viscosity of the surfactant solution with concentration were also important factors that affected the coal's wettability.

The dynamic contact behavior between multi-component droplets and the surface of iron ore dust was taken as the research object, analysis of the maximum spreading coefficient, maximum acting diameter, maximum acting area, and maximum bouncing height of solid-liquid contact, from a microscopic perspective, using high-speed photography and image analysis and processing technology. The experimental results indicate that (1) with the particle size of dust particles decreases, the solid-liquid contact behavior sequentially manifests as spread immediately after broken, retraction, negative bounce, primary bounce, and secondary bounce. (2) When the surface tension of the droplets decreases from 55.5 to 34.8 mN/m, the maximum spreading diameter of the droplet has increased by 30% to 40%, the maximum bounce heights (coefficients) decreased by 100%, 57.14%, and 53.57%, respectively, the maximum spreading coefficient of the droplet exhibits no obvious pattern. (3) With decreasing droplet surface tension, the unidirectional acting diameter and the maximum acting area increase when the dust surface size is over 100 μm. When the surface particle size is less than 100 μm, there is no significant change in the unidirectional acting diameter and maximum acting area despite decreasing surface tension. Thus, droplet diffusion is mainly influenced by particle size. These findings contribute to enhancing the theory of water mist dust removal and improving dust removal efficiency.

The working face blasting dust of Dexing Copper Mine was taken as the research object, and hydrophilic dust (HD, sinking quickly to the bottom) and hydrophobic dust (HCD, floating on the surface for a long time) were separated. The wettability was quantitatively characterized by measuring the wetting contact angle of the two, and the physicochemical properties of the dust particles were comprehensively characterized by measuring the particle size distribution, surface properties, elemental composition, and phase composition of the dust particles. Finally, by comparing the differences in physicochemical properties between HCD and HD, the key factors affecting the wettability of dust were investigated. The results indicate that the wetting angle of HCD is much smaller than that of HD at any given time. When the wetting contact angle of HCD reaches 20° and is in a relative equilibrium state, HD tends to 0°. In terms of wetting properties, the average particle size of HCD is 21.97% smaller compared with HD, which makes HCD have a larger mass-specific surface area, surface energy, and surface activity. Additionally, the true density of HCD is 4.54% lower than that of HD. HCD is less affected by gravity and has a more complex surface pore structure, resulting in a more pronounced air film effect on the surface of dust particles. The formation of an air film greatly weakens the dust’s wettability. Therefore, particle size and surface structure are the main factors affecting the dust’s wettability. Organic substances cannot be detected in the HCD and HD spectra, indicating that both HCD and HD are hydrophilic phases, which determines the overall wettability of blasting dust. The phase composition of HCD and HD is similar, and the difference in the content of hydrophobic groups (C-C, C-H) between them is less than 3%, so the surface groups are not the main factors affecting the wettability of dust.

The number of building occupants is an important indicator for predicting building energy consumption and developing control strategies for building automation. However, most occupancy estimation models were developed depending on the training steps where the true number of occupants is necessary. In order to calculate the occupant number independently, the newly-developed parameter estimation models were proposed, which are based on Maximum Likelihood (ML) approach and Bayesian analysis. A combination of multiple common measurements is used, including real-time CO2 concentration, energy consumption of facilities and make-up air system. The model starts by smoothing the raw CO2 concentration data using moving average, two-hour median as well as globally smooth. Then, ML and Bayesian analysis are used to establish the occupancy estimation models. The proposed models are evaluated in a commercial office which contains 36 occupants for validation. We find that the calculation errors could be reduced by using moving averaged data and globally smoothed data. The superiority of the parameter estimation models can be identified based on its lower calculation error and higher calculation accuracy compared to the previous established models. Practical Application Occupancy estimation models developed in this study are able to calculate occupant numbers independently and accurately in a non-intrusive way based on the indoor carbon dioxide concentration. This can provide input to a predictive building controller based on the application of occupancy estimation models. This could be applied to buildings across a district, informing demand-side management systems by employing occupancy behaviour and energy characteristics of individual buildings. This could allow both utility companies and building operators to simultaneously optimise their performance and benefit from this dedicated control strategy.

Coal's low-temperature oxidation (LTO) poses a significant threat to the safety of storing coal in silos. This study investigates the impact of coal dust content on the LTO characteristics of silo coal samples. The results indicate that the larger the coal dust content the higher the oxygen (O

To investigate the factors affecting the wettability of copper mine blasting dust, the primary blasting dust was collected from an open-pit copper mine and separated into hydrophilic blasting dust (HLBD) and hydrophobic blasting dust (HBBD) using water flotation method. The physicochemical properties of HLBD and HBBD were measured and compared with each other. The properties included particle size distributions (PSDs), micromorphologies, pore structures, mineral components and surface organic carbon functional groups. The results show that particle size and pore structure of the blasting dust are the main factors affecting its wettability. Specifically, particle size of HBBD is smaller than that of HLBD, and their respiratory dust (less than 10 µm) accounts for 61.74 vol% and 53.00 vol%, respectively. The pore structure of HBBD is more developed, and the total pore volume of HBBD is 1.66 times larger than that of HLBD. The identical mineral compositions were detected in HLBD and HBBD by X-rays diffraction (XRD); however, the surface organic hydrophobic component of HBBD is slightly larger than that of HLBD, this may be the reason for the poor wettability of HBBD. This study is significant to understand the effects of physicochemical properties of copper mine blasting dust on its wettability.

Four types of meager and meager-lean coal and one type of high-quality anthracite were selected based on the safety requirements for blast furnace coal injection and domestic coal quality to conduct microstructure and component analyses. The analyses of the organic and inorganic macerals and the chemical compositions of the selected coal samples indicate that the four types of meager and meager-lean coal have low volatilization, low ash content, and low sulfur content; these qualities are suitable for blast furnace injection. Grindability test was conducted on the four types of meager and meager-lean coal and the anthracite mixed coal samples. Results indicate that the mixture of meager and meager-lean coal and anthracite is beneficial to improve the grindability of pulverized coal. The explosive tests reveal that the selected coal samples are non-explosive or weakly explosive. When the proportion of meager and meager-lean coal is less than 40wt%, the mixed coal powder would not explode during the blowing process. The minimum ignition temperature test determines that the minimum ignition temperatures of the four types of meager and meager-lean coal and anthracite are 326, 313, 310, 315, and 393°C, respectively. This study provides a guiding research idea for the safety of meager and meager-lean coal used in blast furnace injection.

Local exhaust ventilation is an important method of contamination control, and the type of exhaust hood and the air distribution at the hood face have an important influence on the contamination control effect. When the hood face is large, it is difficult to create a uniform airflow distribution at the hood face, which if achieved, could improve the effect of contamination control. To that end, the large-area workbench used in the process of vaccine purification was taken as the research subject prototype for this study. According to the methods for generating a uniform airflow distribution at the hood face, the lower exhaust workbenches of four structures were established using CAD and simulated using Ansys Fluent. The best uniformity of workbench surface air distribution was with Structure-4, while the worst was with Structure-1. The workbench surface airflow distribution could not achieve uniformity when only an inclined bottom was used for the large-area lower exhaust workbench with one side outlet. The more internal slits there were, the greater the air distribution area and the more uniform the air distribution. The width of the area of workbench surface airflow distribution was determined by the width of the slits. The numerical simulation results were verified by experiments, which showed them to be credible.

Sodium chlorate (NaClO3) is suitable for use in an area of refuge as the backup chemical oxygen source. To explore the catalytic mechanism of metals and Co3O4 on NaClO3, the addition amount was studied. In this research, 18 samples were prepared by adding different concentrations of Fe, Mg, and Mn (2%, 4%, 6%, and 8%) with Co3O4 (2%, 3%, 4%, 5%, and 6%), and some thermogravimetric experiments were conducted. The results show that the initial decomposition temperature of NaClO3 is reduced from 522 to 255–270 °C by Co3O4. There are two stages in the decomposition process of NaClO3 under the catalytic effect of Co3O4. The catalytic effect of 5% Co3O4 on NaClO3 decomposition is the greatest among the tested amounts. In addition, the proportion of metals has little effect on the initial decomposition temperature of NaClO3 when 5% Co3O4 is added, but NaClO3 has better oxygen performance when the mass fraction of metals is 4–8%. The highly active Mg destabilizes the decomposition of NaClO3, and Mn is more suitable than Mg/Fe for addition into NaClO3. The above conclusions help improve the oxygen supply application of NaClO3 in an area of refuge.

Chemical oxygen generators (COGs) have been used worldwide in confined spaces as an emergency oxygen supply technology, mainly because they are independent and have a long shelf life. However, a number of challenges related to COGs remain unsolved, and a literature review of the current state of the technology is needed. First, the present article summarizes the basic information and applications of COGs, including their oxygen production mechanism, components, forming technology, and ignition system. Four current challenges encountered in applying COGs are discussed, along with the strategies adopted thus far to solve these problems, as found in the published literature. The literature survey reveals that, although much effort has been devoted to controlling the oxygen production rate and the heat output of COGs, the mechanism of producing toxic gases remains unclear and a reliable and safe ignition system has not been fully developed. Finally, future opportunities in the development of COGs are briefly listed.

The micromorphology and physicochemical properties of hydrophobic blasting dust (HBD) from an iron mine were comprehensively analyzed by laser particle size analysis (LPSA), scanning electron microscopy (SEM), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS). The results show that the HBD particles can be classified into three types based on their particle size (PS): larger particles (PS > 10 µm), medium particles (1 µm ≤ PS ≤ 10 µm), and nanoparticles (PS > 1 µm). The cumulative volume of respirable dust (PS > 10 µm) was 84.45%. In addition, three shapes of HBD were observed by SEM: prism, flake, and bulk. In particular, the small particles were mostly flaky, with a greater possibility of being inhaled. Furthermore, the body and surface chemical compounds of HBD were determined by XRD and XPS, respectively. Ammonium adipate (C6H16N2O4) was the only organic compound in the body of HBD, but its mass fraction was only 13.4%. However, the content of organic C on the surface of HBD was 85.35%. This study demonstrated that the small-particle size and large amount of organic matter on the surface of HBD are the main reasons for its hydrophobicity, which can provide important guidance for controlling respirable dust in iron mines.

In this work, a self-hardening foam-sol (SHF) is proposed to control the diffusion of static coal dust. The SHF was mainly synthesized by a foaming solution (composed of 1 g/L polyethylene oxide (PEO), 25 g/L sodium dodecyl sulfate (SDS), 100 g/L sodium silicate and 874 g/L water) and organic acid with a concentration range of 10 to 13 g/L. Based on fluorescence spectrophotometry, drop shape analysis, X-ray photoelectron spectroscopy and scanning electron microscopy, several conclusions could be found. The critical micelle concentration of SDS was 25 g/L, when most of the pyrene pendants were solubilized into the SDS micelles to form the hydrophobic mixed micelles, and excimer formation began to reach a maximum. The SHF had optimal wetting ability with the smallest contact angle of 17o, due to PEO-bonded water and SDS forming hydrogen and a dual adsorption layer, which could enhance the wetting ability of the SHF on coal dust surfaces. The SHF had the best accepted loss of liquidity time (180–86 s) and self-hardening time (236–121 s) via the reaction of sodium silicate and organic acid. The pores and cracks among dust particles could be linked closely by SHF via the solid bridge force. The primary components were silica and sodium carbonate with crystal water and hydrophilic C O and C O or O–C–O functional groups. Based on the dust suppression experiment, the dust suppression efficiency was almost 100% at airflow speeds below 12 m/s. Obviously, the dust particles could be controlled via their surfaces being covered by a layer of SHF, since the SHF has strong hydrophilic properties and the solid bridge force. In addition, vehicle-mounted SHF preparation equipment was designed.

In order to explore the law of construction workers’ heart rate change in fatigue state, the heart rate was used as a parameter to build the evaluation calculation model.. Five healthy participants (male) were selected to imitate construction by engaging in bricklaying. 3 simulation platforms are designed to simulate the effect of repeated brick moving on fatigue life of masonry workers at different height walls. The results showed that the change of relative heart rate accords with "s" type. According the theory the average relative heart rate of the volunteers increased fastest in the early stage and higher than the other two platforms in the middle and high platform (simulated job at the height of the waist height of 86cm). The average relative rate of heart rate rising was relatively slow at the early stage of the low high platform (simulated at the knee height of 48CM). The average relative heart rate changes of the volunteers were not changed at the first and middle stages of the highest platform. The average relative heart rate was similar to the middle and high platform at a slow rate, and the average relative heart rate was similar to the middle and high platform. Using this model, the fatigue state of construction workers can be evaluated.

To understand the heterogeneous behavior of oil–particle aggregates (OPAs) in the riverine environment as well as the uncertainties caused by the coupling effects between their stochastic formation and transportation processes, this study employed the coagulation conceptual formula and random-walk particle tracking model. Through careful inspection using the classic Rouse–Vanoni diagram and existing laboratory observations, a vertical diffusivity scheme and the packing coefficient for an oil–sediment interaction model were determined. The density variations and deposition patterns of hypothetically fully developed OPAs as well as the impact of oil–sediment interactions on the longitudinal distribution of deposited OPAs were then investigated. The results indicate that the formation process of OPAs has a significant effect on their longitudinal deposition. The range of potentially trapped OPAs varied from several to hundreds of times the range of cases that exclude oil–sediment interactions. The deposition diagram proposed in this study visualizes the relationship between the configuration and deposition pattern of OPAs and can assist in determining the most unfavorable scenarios for oil-spill countermeasures. Further refinement and calibration of the model are necessary in the future to provide guidelines for oil spill responses and recovery in riverine environments.

Novel DOPO/silicon/CNT nanohybrid flame retardants (FR-CNTs) were synthesized and FR-CNTs were introduced into epoxy resins through thermal curing process. The SEM and TEM results indicate that CNTs distribute uniformly in epoxy resins due to the good dispersion of CNTs in DOPO/silicon/CNT nanohybrid flame retardants. The thermal stability and flame-retardant properties of EP/FR-CNTs composites are improved, which is attributed to the good dispersion of DOPO/silicon/CNT nanohybrid. The cone calorimeter results demonstrate that FR-CNTs can reduce peak heat release and the release of toxic gas effectively compared with EP/CNTs and EP/CNT/FR composites. The char-residue analysis indicates that the improved flame-retardant properties are due to the char-reinforcing effects and the catalyzing charring effect of FR-CNTs, which provides enough time for flame retardants to trap radicals. Generally, the char layers, which act as insulating barrier, can reduce the releasing of flammable gases and protect the underlying epoxy resins from the heat source.

To effectively promote the capacity of fire brigade to handle the building fire and improve the effect of building fire simulation training, a set of design procedure of simulation training module of building fire simulation training facility is proposed in this paper based on the theoretical calculation and according to the field investigation. Such procedure is capable to provide the training environment with the high degree of simulation and complete functions for the fireman and effectively promote the training effect.

To provide an optimal aerodynamic sealing solution for an alternative refuge in underground mine, a commercial air knife was selected as the air curtain device (ACD) for its lower compressed air use and uniform airflow. A series of simulated chamber model experiments were then performed to evaluate the sealing efficiency of different ACD configurations and the influence of interruption by transiting personnel on ACD performance. By considering the overall sealing efficiency, stability and air consumption, a double-sided ACD equipped with a baffle on the side exposed to harmful gases inside the entrance of the protected door is proposed as the most suitable configuration. This requires compressed air to be supplied at a pressure of 0.10–0.20 MPa to generate an air barrier, which means that a standard compressed air cylinder (40 L, 15 MPa) can provide suitable sealing conditions for a period of about 3.5 min.

This paper presents the design of an innovative mine emergency rescue relay cabin, and investigates a detailed comparison of existing shelter facilities, their function, service object, structures, size, and system components with the newly designed mine emergency rescue relay cabin. Air-tightness test indicated a test chamber relief rate of 26 Pa/min, which meets the design requirements. Furthermore, respirator replacement test showed an average time of 73.7 s to replace a respirator. The air cover air supply test indicated an air supply rate of 220 L/min, which is sufficient for the staff replacing the respirator in the emergency rescue relay cabin. The total air supply volume is 9680 L, which can be supplied via two compressed air cylinders of 40 L, pressurized to15 MPa. Keywords: Relay cabin site selection, System and structure, Air tightness, Air cover air supply

Potassium superoxide-based oxygen supply systems demonstrate a tremendous potential for applications associated with mine emergency rescue. In this study, the air revitalization performance of a potassium superoxide plate operating under natural convection conditions was investigated by a series of passive tests in a sealed chamber. Reaction resistance analysis based on experimental data revealed that increasing air temperature and humidity accelerates oxygen generation but reduces the system respiratory quotient as a result of the increased resistance of internal diffusion. Increasing the amount of plates or using them in combination with a carbon dioxide absorption curtain is a practical, effective method for meeting requirements of both oxygen generation rate and system respiratory quotient in underground refuge. Kinetics model that predicted the mean oxygen generation rate, carbon dioxide absorption rate, system respiratory quotient and total thermal output (Q) was also derived from experimental data in this study. Predicted results were found to be in good agreement with experimental data. The proposed model can aid in the design of air revitalization systems used in refuge stations for underground mines.

This study aimed to develop a proper control strategy for a forced-circulation ice thermal storage system (ITSS) designed for a permanent refuge chamber with an accommodation capacity of 50 persons. The heat transfer characteristics of the ITSS were investigated through theoretical and experimental approaches. A quasi-steady one-dimensional mathematical model for predicting the transient discharging power was proposed. On this basis, a control strategy was proposed to fulfill the minimum cooling requirement in consideration of both effective discharging time and human comfort. The minimum required velocity of the ITSS was analyzed; from this, the effective working time of the ITSS was determined to be 64.57 h. Additionally, the heat load inside the chamber was found to be the main factor that affected the effective temperature control duration and the utilization ratio of the ice. Thus, a reserve factor, which is defined as a function of rated heat load and determined by the discharging performance model, is suggested for consideration during optimization.

A parallel-flow exhaust hood is an effective ventilation device to control dust and toxic pollutants and protect the occupational health of workers, whether it is used alone or combined with a uniform air supply hood in a push&ndash, pull ventilation system. Some scholars have studied the outside air flow characteristics of the conventional exhaust hood with non-uniform air speed at the hood face, but the law of velocity variation outside the parallel-flow exhaust hood is not clear at present. Therefore, this paper uses the dimensionless method to study the center-line velocity change regime in a parallel-flow square exhaust hood based on simulation and experimental data. The results show that the dimensionless center-line velocity has a good change law with the characteristic length of exhaust hood in a parallel-flow square exhaust hood, which can eliminate the influence of hood face velocity and the hood size on the velocity change regime, and the experimental data is basically consistent with the calculated data, which shows that the regression equation method is reliable.

Complex antioxidant enzyme inhibitor (SC), as an innovative technology was proposed, which mainly includes polyethylene glycol-Cu,Zn superoxide dismutase (PEG-SOD), Mn catalase (CAT) and sodium dodecyl sulfate (SDS). It exhibits excellent performance in inhibiting the low-temperature oxidation of coal. This study includes wettability of SC solution and the thermal characteristics of SC suppressing the self-heating of coal. For wettability of SC solution, it was found that the nuclei of the PEG polymer could adsorb hydrophilic groups of SDS to form an outer PEG polymer layer through chemical shift alterations, and the inner SDS tail groups were adsorbed at the hydrophobic coal sites, leading to an SC solution with excellent wetting ability on the coal surface. For the thermal characteristics analysis, the SOD and CAT contained in SC could quickly neutralize superoxide radicals through a disproportionation reaction below 90 °C; the PEG, with the thermoplastic properties of SC, could fuse to form a colloid that could wrap onto the coal surface to form a protective layer below 150 °C. Research results indicated, as for coal-SC, that chain propagation reactions were terminated, homolysis of chemical bonds to generate new free radicals was prevented, and the free radical concentration obviously decreased on the coal surface; the relative content of C O groups obviously decreased, that of C C/C H groups gradually increased, and those of C O/O C O and O C O groups remained almost constant with increasing temperature; oxygen adsorption was significantly reduced, leading to an obvious decrease in oxidation of active groups to form surface oxides.

The effects of the molding pressure of a KO2 oxygen plate and the initial concentration of CO2 on the oxygen generation rate, the oxygen generation efficiency, and the carbon dioxide absorption rate were studied using a YES-300 hydraulic press to alter the pressure when forming the oxygen plate used in a coal mine refuge chamber. In addition, changes in the initial concentration of CO2 used in the closed-box model were made by adjusting the CO2 supply system, and a CD-7 multi-function parameter instrument was employed to monitor and record the changes of O2 and CO2 concentration in the closed-box model. Results indicate that the oxygen generation rate of KO2 oxygen plates, the oxygen generation efficiency, and the carbon dioxide absorption rate decrease when there is an increase in the pressure used to mold the oxygen plates, but those values increase when the initial CO2 concentration increases. When the initial concentration of CO2 in the closed-box model is 3.5% and the forming pressure is 10 kN, the average oxygen generation rate of 15 g KO2 oxygen plate is 11.88 × 10−3 L/min, the oxygen generation efficiency is 80.3%, and the average CO2 absorption rate is 11.0 × 10−3 L/min. Compared with the condition where the initial CO2 concentration is 1.5%, the results show that average oxygen generation rate of oxygen plates increases by 88.9%, the oxygen generation efficiency increases by 88.9%, and the CO2 absorption rate increases by 100%. Keywords: Potassium superoxide, Oxygen generation rate, Oxygen generation efficiency, Carbon dioxide absorption rate, Concentration

This study introduces the current situations of the research on the refuge chamber at home and abroad. Aiming at disasters prevented and environment for refuge chamber, it deals with the chamber's protection and positioning, notes for selection of chamber sites, reference sizes and requirements of strength and impermeability. Some designs for survival system in the refuge chamber are structured, including multistage oxygen supply, air cleaning system, temperature and humidity control system, dynamical system, monitoring and communication system, etc.

Based on adsorption isotherm experiment on two coal samples under different temperatures using the HCA adsorption parameters determinator, the effect of temperature on adsorption capability of coal/CH4 was analyzed. The prediction of adsorption capability of coal/CH4 of 20°C, 40°C, 50°C, 60°C were done using the adsorption characteristic curves of 30°C by adsorption potential theory, and compared with the experimental date. The results show that, in the research temperature and pressure range, the adsorption amount and saturated adsorption amount a decrease as the adsorption temperature increases, relation between saturated adsorption amount a and temperature can be described by an exponential function, the variation of adsorption constant b is non-monotonic. It is concluded that there is no relationship between the adsorption characteristic curve and temperature of coal/CH4 adsorption system. The relative error in saturated adsorption amount a prediction is 1.23%∼3.80%, the relative error in adsorption constant b prediction is 1.09%∼5.26%, and the prediction effect is better.

A proper understanding of spontaneous oxidation and combustion tendency of sulfide ores is of great importance for the assessment and mitigation of possible spontaneous mine fire in practice. Series of test study for typical sulfide ores under temperature programmed oxidation (TPO) conditions were presented in this conference paper, with the aim of correlating the spontaneous combustion tendency and the measurements of total oxygen uptake and starting temperature of self-heating. Also relevant nitrogen adsorption properties, including specific surface area and pore- size distributions, for the same set of sulfide ore samples were determined using the Brunauer-Emmett-Teller (BET) method and the Barret-Joyner-Hallender (BJH) method, respectively. The test results demonstrate that for the sulfide ore samples collected from a spontaneously combusting mine, The total consumptions of oxygen during TPO test were relatively larger in comparison with those sample from a mine without spontaneous fire record in history. Also it is shown that the microstructural surface features of the ore samples may have an effect on the oxygen consumption response during TPO test.

Metallic corrosion is a serious problem in the application of a hygroscopic inorganic dust-depressor. The basic characteristics of a hygroscopic inorganic dust-depressor and its corrosivity, corrosion mechanism, as well as the principle of corrosion inhibition were analyzed. The static mass-loss test was carried out to investigate the corrosion behavior and the effect of the dust-depressor. The static corrosion rates of steel specimens were measured in six different corrosion inhibitor solutions of the dust-depressor, and the suitable corrosion inhibitors for the dust-depressor to reduce the corrosivity were found out.

Emergency response and rescue process in chemical accidents is the representative of discrete event dynamic system. In order to dynamic evaluate the emergency response capability in chemical accidents, the paper introduced Petri net for the modeling and analysis of emergency response process in chemical accidents, analyzed its structure, and obtained some important measures for performances analysis of the process. The research result shows that the methodology is simple and reasonable for emergency response capability evaluation, which can greatly help fire commanders to identify weaknesses in response capability and to optimize the rescue teams in chemical accidents.

There are many methods used for modeling of emergency response capability. Stochastic Petri net is a better choice because of the strict mathematical definitions and analysis methodology. In order to dynamic evaluate the emergency response capability, the paper introduced stochastic Petri net for modeling and analysis of emergency response process. Taking chemical accident as an example, the paper analyzed its structure, and obtained some important measures for performance analysis of the process. The research result shows that the methodology is simple and reasonable for emergency response capability evaluation, which can greatly help fire commanders to identify weaknesses in response capability and to optimize the rescue teams.