FORECASTING EMERGENCY SITUATIONS AND THE DEVELOPMENT OF ACCIDENTS IN THE STORAGE OF LIQUEFIED HYDROCARBON GASES

In recent years, there have been fundamental changes in the industry due to a change in the structure the use of primary energy resources. For most the developed countries of the world, one the components of changes in industry was the emergence and constant increase in the share of chemical, fire and explosive technologies and industries using liquefied gases, primarily hydrocarbons – propane, butane, ethylene, butylene, propylene and others. The aim of the work is to analyze possible emergency situations at the storage facilities of liquefied hydrocarbon gases and predict possible scenarios for the development of accidents in the places of their storage, as well as develop recommendations for the prevention of these dangerous situations. The main reason for the leakage of the tank is mechanical or corrosive wear, as well as errors of operating and maintenance personnel. Other reasons (pressure exceeding critical values, accidents at neighboring blocks, natural factors, etc.) that can lead to a leakage of the storage facility with liquefied gases are less likely, but they cannot be completely excluded. A salvo leak a large amount of vapors liquefied petroleum gases is unlikely due to the underground location of the tanks. Considering the reasons for the violation of the tightness the pipeline with liquefied hydrocarbon gases, it should be noted that a large pressure value is not created in the pipeline during its operation, which can lead to a violation of the tightness the pipeline along the pipe body. Therefore, the most probable violation of the tightness the pipeline as a result the departure of technological parameters beyond the critical values ​​should be considered a violation the tightness of flange connections and stuffing box seals of valves. Violation of the tightness the pipeline due to corrosive wear is most likely as a result of external factors affecting the pipeline (atmospheric phenomena). It is impossible to predict the extent of the leakage and their location. Thus, a detailed analysis the causes of the occurrence were carried out and a probable scenario the development of accidents at the storage of liquefied hydrocarbon gases was considered. A logical diagram of the occurrence and development of accidents has been built. Recommendations have been developed for the prevention of emergency situations at storage facilities of liquefied hydrocarbon gases and the actions of employees in case their occurrence.

Using the flammability potential and the exergy indicator to assess the fire hazard of the rail transportation of cargoes

Introduction. Problems of fire safety of dangerous goods (DG) in the process of their rail transportation have not been fully resolved. The flammability assessment of substances and materials is insufficiently impartial; an integrated indicator, that allows to apply a consolidated methodological standpoint to improve their energy efficiency and environmental/fire safety is unavailable.The purpose of this work is to substantiate the feasibility and advantages of the exergy approach to assessing the fire hazard of the exhaust gas emitted from railroad transport.Materials and methods. The use of the flammability potential as an integrated indicator of the fire hazard of cargoes has a number of limitations. The exergy approach has a strong potential if applied to the assessment and prediction of fire hazards. Present-day and potential railroad cargoes serve as examples that substantiate the feasibility of this approach.Results and its discussion. Dependences between fire hazard indicators (flash points, flame propagation limits, auto-ignition points, heat of combustion) demonstrated by the components of liquid and gaseous fuels and the chemical exergy were identified.A study of changes in the physical exergy triggered by spills and combustion were illustrated by liquefied natural gas and liquefied hydrocarbon gases having various compositions. Physical exergy change patterns depending on the temperature and pressure of the above products were developed.For self-ignitable cargoes, dependences between the physical exergy and activation energy, critical ambient temperature, and heat capacity of self-heating materials were identified. The influence of thermal conductivity and humidity coefficients on the exergy value is established.Exergy changes were determined depending on the elemental composition of solid municipal waste, ash, volatile matter and fixed carbon content. Polymers and rubbers have the highest values of this indicator.An exergy indicator was introduced to assess fire and environmental hazards of substances and materials; it serves as the basis for the classification of cargoes.Conclusions. The use of the exergy indicator allows to increase the objectivity of assessments and take account of technical, economic, environmental criteria and indicators of fire hazards within an integrated system.

The concept of building training systems for training operators of liquefied hydrocarbon warehouses

The article deals with the concept of building computer training complexes as one of the effective aids for ensuring the safety of potentially dangerous technological processes which include the storage and transportation of liquefied hydrocarbon gases. The authors have developed and described simulator model of one of the key technological devices for the storage of liquefied hydrocarbons which underlies the proposed software platform for the synthesis of training simulator systems.

Conversion of Liquefied Hydrocarbon Gases on Commercial Nickel Catalysts

The two-step conversion of industrial liquefied hydrocarbon gases (LHG) on NIAP-07-01 (NKM-1) and NIAP-03-01 catalysts for the production of hydrogen-containing gases was investigated. The experiments were carried out in flow reactors with a fixed catalyst bed at a pressure of 0.1 MPa under the following conditions: temperature 350–450 °C, gas hourly space velocity (GHSV) 1000–3000 h–1, steam-gas ratio 4 : 1–8 : 1 (pre-reforming); and temperature 700 °C, GHSV 2000 h–1, air-gas ratio 1.2 : 1 (steam-air reforming). Under the studied conditions, the concentrations of components of the converted gas correspond to the equilibrium values calculated within the Peng-Robinson model. The conversion of methane homologs in the pre-reforming step was found to be virtually 100 %; therewith, the methane concentration reached 32–54 %, and that of hydrogen, 24–47 %. To prevent the formation of elemental carbon (carbonization), pre-reforming of hydrocarbon gases with a high methane equivalent should be performed at H2O : C > 2. In the two-step reforming, the yield of hydrogen-containing gas reaches 15.6 m3 from 1 m3 of the initial LHG with the hydrogen content 41.81 %, and the total content of CO and H2 exceeds 52 %.

Ni/MgO catalysts on structured metal supports for air conversion of lower alkanes to synthesis gas

A series of thermostable heat-conducting selective catalysts for air conversion of lower alkanes to burn-initiating fuel additives fed as synthesis gas to fuel were developed based on nickel-containing highly porous foam-cellulous material (HPCM) and a net-shaped support. The catalyst synthesis included stages of preparation of the support based on Ni-HPCM (Ni 99,95 %, PPI = 40) or fechral grid, arrangement of the support surface and formation of structured units, thermal treatment of the samples, supporting of the active component via repeated impregnation with a combination of magnesium and nickel acetates, and stepwise thermal treatment. Thus prepared catalysts NiO-MgO/(HPCM or fechral) were tested in the reactions of air conversion of propane, propane-butane, natural gas, as well as tri-reforming. In all the 80–100 hour experiments, the catalysts provided 90–96 % conversion at the flow rate of 32000–71000 h–1, no coke formation being observed at the air excess coefficient of 0.31–0.43. A two-phase two-temperature mathematical model of the air conversion of liquefied hydrocarbon gases (LHG) was developed for the numerical analysis of the results obtained; the modeled results agreed well with the experimental data on temperatures of the catalyst and flow, as well as on the composition of the outlet gas mixture. A generator of 100 kW heat power for the air conversion of LHG was calculated as a practical example.

THE COMBINED USE OF THE RADAR METHOD AND THE METHOD BASED ON THE DIFFERENTIAL PRESSURE FOR LEVEL MEASUREMENT IN STORAGE TANKS OF LIQUEFIED HYDROCARBON GASES AND HIGHLY FLAMMABLE LIQUIDS UNDER PRESSURE

The article shows the difference between the present and previous requirements of safety regulations in the field of level control in spherical tanks for storage of liquefied hydrocarbon gases and flammable liquids. The description of two of the most currently used methods of level control is given, their advantages and disadvantages are presented. The design features of the structure of spherical tanks, methods of joining them to the level control sensors are described. The dependence of the density change of the liquid product on the temperature change is shown. The changes in the ambient temperature associated with sharply continental climatic conditions of geographical location of the West Surgut field are described. The article demonstrates the complexity of monitoring the temperature and density of the working fluid in the heat exchange between the liquid and the environment due to the initial temperature differences between them. The quality assessment of level measurement and calculation of product density change in spherical tanks using two methods of level measurement is given. In addition, the method of recalculating the readings of the two principles of level measurement is shown, which makes possible to calculate the density of the liquid, to monitor changes in density, without data on the current values of the liquid temperature.

Calculation of a two-phase system of a liquified hydrocarbon gas

Liquefied hydrocarbon gases are a mixture of chemical compounds, consisting mainly of hydrogen and carbon with different molecular structures. The main components of liquefied hydrocarbon gases are propane and butane, containing lighter hydrocarbons (methane and ethane) and heavier ones (pentane) in the form of impurities. All of these components are saturated hydrocarbons. The composition of liquefied hydrocarbon gases can also include unsaturated hydrocarbons: ethylene, propylene, butylene. Butane-butylenes may be present as isomeric compounds (isobutane and isobutylene). When designing and operating liquefied petroleum gas systems, it is necessary to take into account the external equilibrium between the liquid and the gas. The paper analyzes the change in the ratio of components, in which the relative content of lighter hydrocarbons will decrease, while the content of heavier ones will increase. With an intensive flow of gas, the temperature of the liquid will drop sharply, estimation will be disturbed, and the vessel will freeze. Therefore, when operating balloon installations, it is very important to consider safety issues that are associated with containers’ filling, as well as with the change in the composition of hydrocarbon gases mixture. The discussed issues related to the calculation of a two-phase system of liquefied hydrocarbon gas can improve the operating conditions of the systems.