RU2061641C1 - Method of dust suppression when stockpiling and handling of coal at below zero ambient temperatures - Google Patents

Abstract

FIELD: dust suppression. SUBSTANCE: coal pile is formed at sprinkling inside movable chamber where microclimate with above zero temperature is created by delivering warm air. EFFECT: enhanced suppression of dust. 4 dwg

Description

 The invention relates to the mining industry and can be used in the operation of emergency and intermediate coal depots in mines and open pits.

 Coal storage in emergency and intermediate warehouses with the formation of stacks using stackers is accompanied by dustiness in the atmosphere in the areas where objects are located. In the process of stacking, the dust that is formed during the destruction of coal at the technological stages during its mining and transportation is winnowed. A dust cloud is carried away by air currents over long distances, increasing the radius of the harmful effect of an object polluting natural complexes. The situation is complicated by the fact that coal depots are located in open areas exposed to airflows in all directions, which contributes to the uplifting of dust from the side surface of stacks and adjacent territories and an increase in the concentration of fine dust in the atmosphere of warehouses.

 In the autumn-winter period, with the onset of negative air temperatures and the impossibility of applying the traditional dust suppression-irrigation method under these conditions, coal depots remain unprotected with all the ensuing consequences.

 Considering that in the northern regions of the country, negative air temperatures persist for 200 days a year, the unresolved issues of dust control in coal depots at sub-zero temperatures bring irreparable damage to the environment and people who fall into the zone of influence of dust loading. In addition, the uplifting and removal of dust from the warehouse leads to the loss of finished products in the hundreds of tons.

 In this regard, the search for ways to reduce dust emissions during storage of coal and its losses is one of the most urgent tasks.

 There is a method of combating dust during storage and processing of coal piles in conditions of negative temperatures of atmospheric air, which consists in irrigation of stored coal piles (reference: I. G. Ischuk. Means of complex dust removal of mining enterprises. M. Nedra, 1991, p. 224).

 This method is widely used in the mining industry and is one of the most effective, but in this case, when stacking piles with free falling of coal from the stacker conveyor to the stack pads and the absence of a closed (limited) space, it does not allow to obtain the necessary effect due to dust from an incident jet of coal, which is not possible to wet on a stacker conveyor belt with all its bulk capacity due to the hydrophobicity of coal. With the onset of the cold periods of the year in conditions of negative atmospheric air temperatures, it is difficult to apply irrigation with existing dust suppression technologies, which include the supply of dispersed water to the belt and the dumping head of the stacker, due to the freezing of nozzles and supply pipelines.

 Thus, existing irrigation technologies do not provide the necessary dust suppression efficiency when forming coal stacks and other bulk and dusty cargoes using stackers, as well as the possibility of using irrigation in subzero temperatures of atmospheric air.

 The technical result of this invention is the development of a method of combating dust when storing coal and other bulk and dusty goods in stacks using a stacker.

 This goal is achieved by the fact that irrigation is carried out inside a mobile chamber, in the volume of which a microclimate is created with a positive thermal regime by supplying thermal air to it.

 The implementation technology of the proposed method is illustrated by drawings, where: in FIG. 1 shows a schematic diagram of the beginning of the formation of the stack; in FIG. 2 stacking process; in FIG. 3 location of the working window in the heat chamber; in FIG. 4 layer thermal insulation chamber.

 The formation of the stack begins with the erection or preparation of the thermal chamber 1, if available, which is a shelter that limits the stack according to its dimensions, due to the height, width along the upper and lower parts, as well as the angle of repose. The heat chamber at its base rests on a platform that has wheelsets 2 on both sides of the stack, moving along rails 3 stacked taking into account the width of the stack on the sole (base) so that a gap is provided between its sides and the shields of the heat chamber 4 moving the camera. Wheels can be borrowed from mine trolleys. In the upper part, the side shields have a rigid connection between them, which ensures their fixation in a position parallel to the sides of the stack. The end part of the chamber is also blocked by a shield 5 having bolted or welded joints with side shields, creating a closed volume around the chest of the stack. The heat chamber is supplemented with aprons 6, which are a conveyor belt, bolted to the side shields. Aprons close the working space of the heat chamber, without interfering with its movement as the stack is dumped. The chamber is also blocked from above by a shield 7, leaving the working window 8, which makes it possible to supply the stored material from the stacker of the stacker 9 to the stack, the chest of which (its end part) is insulated by the heat chamber.

 The panels forming the chamber are insulated with hardening foams such as polyurethane foam 10. The frame of the welded panels is mounted from separate sections connected by bolts. The frame is welded from pipes or a corner and covered with sheets of galvanized iron.

 The length of the heat chamber depends on the angle of repose of the stored material and is set so that the entire chest of the formed dump from its upper part to the base is insulated by the heat chamber as shown in the drawing.

 In the heat chamber, irrigation devices (nozzles) 11 are installed and inlet hoses for supplying water and compressed air to the sprinklers are mounted. Heated air in the heat chamber and maintain a positive thermal regime in it can be carried out using an electric air heater and a centrifugal fan 12 mounted in a block on the camera platform. Given the limited volume of the heat chamber, neither the air heater, nor the fan will be energy-intensive.

 Irrigation devices are turned on to supply dispersed water after they are pre-purged with hot compressed air supplied by a compressor 13, also installed on the platform of the heat chamber, and heated to positive temperatures. To improve the conditions for maintaining the thermal regime, the space between the sleepers and the end part of the chamber is isolated by an apron 14.

 Irrigation devices are also installed to moisten the side surface of the stack, which freezes after leaving the chamber and contact with subzero temperatures of ambient air, which creates a reinforced layer of coal that prevents blowing and removal of dust from the stack. This is of great practical importance, since this process leads not only to intense pollution of the atmosphere, but also to high losses of coal. In the seaport trade port Vostochny Port in Nakhodka at the coal complex, up to 500 tons of coal per year are lost annually for these reasons.

 The heat chamber is rigidly connected to the stacker, also moving along its rail tracks, which ensures the synchronism of their movement.

 In the initial period of stacking, its first cone is formed directly in the heat chamber, until its top appears in the working window of the chamber. Then the stacker and the heat chamber are displaced in the stacking direction, and the process is repeated.

 To reduce the length of the heat chamber, the formation of the first cone is possible with a phased movement of the stacker during storage as the material is laid with the side of the cone leaving the chamber.

 A dust cloud blocked in a heat chamber is quenched by dispersed water. At the same time, the stored coal or other bulk material is moistened, thereby reducing the dust yield during subsequent processing of the stacks. With water shortages, the heat chamber can be used as an aspiration shelter with a dry dust suction into cyclones or filters. In this case, air heating in the chamber may not be performed.

Thus, the use of a moving camera solves a set of issues related to dust suppression:
the localization of the dust flame during stacking;
prevention of dust entrainment by wind currents;
increasing the efficiency of dust suppression by feeding dispersed water into a concentrated dust cloud;
reduction of coal losses;
the possibility of irrigation, regardless of the ambient temperature;
moistening of the stored material, providing a reduction in dust yield during the processing of stacks;
combining dust suppression with strengthening the side surface of the stack;
the possibility of using a heat chamber as an aspiration shelter, which is extremely important for enterprises experiencing water shortages.

 The heat chamber, as mentioned above, is collapsible and can be mounted anywhere in the warehouse as necessary. With a stationary arrangement of stacks, it is rational to mount the camera on each stack. Camera life is unlimited.

 The lifting and installation of panels mounted on the site is carried out using a truck crane. YYY2

Claims (1)

 A method of combating dust during storage and processing of coal piles in conditions of negative atmospheric air temperature, which consists in irrigating a stored coal stack, characterized in that the irrigation is carried out inside a mobile chamber, in the volume of which a microclimate with a positive thermal regime is created by supplying warm air to it.

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