ENGINEERING SCIENCE / safety

Makhovskiy V.O., Kryukovska O.A.

Dneprodzerzhinsk State Technical University

Analysis of emergency situations at meat processing plants

In most towns or settlements are meat processing companies, factories or shops that provide people a variety of meat products. Meat products involves using kompresors, ressyvers, sevaporatora, oil separators, refrigerators, liquid tankers with nitrogen. The risk of companies that are located near residential buildings and other public facilities and public space, is the probability of accidents and emergency situations involving liquid ammonia emissions.

Based on the analysis of possible emergencies and accidents are possible in meat-processing plants, we can distinguish 5 main process units. Blocks are defined geographically, ie, on the boundaries of the premises and areas in which the equipment is located. The first includes a node charging circuit liquid ammonia compressor workshop; the second - the engine room; block third - space separating capacitor and linear receivers; fourth - capacitor compartment; fifth - refrigerators and piping.

Process parameters for units, installations and pieces of equipment and different objects of study are characterized by their dangers. All hazards inherent in the subject, due to the hazardous properties of the technological environment and the equipment used. For low-temperature flow chart compressor workshop provided the use of toxic substances - ammonia.

Ammonia is a toxic fire explosive substance that refers to class 4 hazard. Auto-ignition temperature ammonia 650 °C, the minimum ignition energy of 650 mJ, maximum explosion pressure 7 kgf/cm², the heat of combustion of ammonia 18619 kJ/kg. At low concentrations of ammonia irritates the upper respiratory tract, causing watery eyes. At high concentrations, it stimulates the central nervous system, causing convulsions. In acute poisoning, death can occur from pulmonary edema and congestive heart failure.

Violations of technological regime and safety regulations can result in: an explosive mixture of ammonia and air in the room engine room; gassed industrial premises, site of the enterprise and the surrounding area with ammonia.

Potentially dangerous meat-processing plants is a violation of the integrity of equipment and pipelines containing ammonia. The result of such accidents is the emergence of gas pollution production area, open area shops and businesses in general, as well as the surrounding residential areas.

The danger with this point of view are: the destruction of the tank with liquid ammonia; Leakage of a circulating receivers; Leakage of one of the linear receivers; Leakage of pipes or shutoff valves in an open area.

The greatest potential danger is the destruction of the pipe or flange connection in the open air, because in the event of depressurization of the evaporator zone of infection will be limited cooling chamber.

If released liquid ammonia produces toxic cloud, localization is technically difficult. To reduce the rate of migration of toxic clouds on its route created water curtain using mobile spray rigs. As the use of water curtains does not provide complete containment and elimination of the toxic cloud, the risk of exposure, in addition to the territory of the compressor plant is the industrial area of enterprise, residential areas and businesses of the city.

The compressor shop at the tightness of equipment containing ammonia, are also possible explosions and fires. Quantitative estimation of the parameters of these accidents suggest that the zone of the damaging factors in this case will be limited outside the production area of the plant.

Local sources of emissions of ammonia may serve process gas compression and injection of liquid ammonia, and the handling of oil operations.

The main dangers are inherent in ammonia-refrigeration, are caused by toxic properties of ammonia and the amount accumulated in the same unit.

When emission of gaseous and liquid ammonia is formed Strait toxic wave power is determined by the mass ejection. The velocity of the gas migration waves and the resulting toxic cloud depend on the climatic conditions, mainly on the state of the atmosphere.

Straits of liquid ammonia is much more dangerous than the emissions of gas, as in the Straits of liquid ammonia gas source formation wave there a long time.

Particular attention should be paid to the risk of water hammer when unskilled operation of the compressor equipment, especially in the start-up period after repairs or prolonged shutdown.

Hazard ammonia emission into the atmosphere in many cases are associated with low quality and unreliable repairs concerning sealed compressor equipment that with high dynamic alternating loads leads to destruction, especially in the field of detachable joints.

As a result of leakage of a tank of liquid ammonia may be emitted and the formation of migrating toxic cloud.

Thus, in order to prevent accidents and emergencies at meat processing plants, and in the event of an accident to minimizing the consequences of an accident is necessary to prevent violation of the integrity of devices, coils, flanges, carry out continuous monitoring of levels of pressure and temperature of ammonia during the process fully adhere to technological regulations.