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Large asphalt mixing plant site installation planning, commissioning and acceptance

Asphalt mixing stations play an important role in road construction. This article starts from the site selection, commissioning, and acceptance of the asphalt mixing plant, and elaborates on comprehensive and reasonable planning to avoid disturbing the normal construction order.

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Asphalt mixing stations play an important role in road construction. This article starts from the site selection, commissioning, and acceptance of the asphalt mixing plant, and elaborates on comprehensive and reasonable planning to avoid disturbing the normal construction order.
1 Site planning of asphalt mixing station
1.1 Site selection requirements
Large-scale asphalt mixing plants occupy a large area, have many types of equipment, must have a certain storage capacity for stone stacking, and are divided into living areas and production areas.
1.2 Principles of site selection
1) When selecting a site, it should be close to the roadbed of this tender section and located near the midpoint of this tender section.
2) Water and electricity sources should be convenient.
3) Adopt convenient transportation of raw materials and finished materials in and out of the mixing station.
4) Consider external factors and try to avoid installing in places with many surrounding residents.
5) It can supply asphalt mixture to several connected pavements at the same time.
1.3 Natural conditions for site selection
1) The environment of the site should be dry, the terrain should be high and the groundwater level should be low. Avoid installing near rivers.
2) When excavating and installing the foundation, you should understand the geological conditions of the site. If the geological conditions are good, such as hard foundations such as sand and gravel, the cost of installing the equipment can be reduced and equipment deformation caused by settlement can be avoided; if the geological conditions are loess foundations, the foundation can be expanded according to the actual situation to improve the foundation’s strength. method.
1.4 Site planning and layout
1) Site planning mainly refers to three major floor plans, including: overall floor plan, installation foundation plan, and low-voltage power system plan.
2) First, the production area and office area should be planned. The polyurethane product production area and living area should all be enclosed with walls. Main buildings and structures in the living area: staff dormitories, canteens, restaurants, and conference rooms. Main buildings and structures in the production area: on-site offices, laboratories, guard rooms, stockyards, power distribution rooms, gates, etc.
1.5 Basic prefabrication
There are many component assemblies of asphalt mixing stations, mainly including mixing station main engine, asphalt storage facilities, finished product silos, thermal oil furnaces, dust removal systems, power distribution rooms, cable trenches, etc. When prefabricating the foundation, the coordinate method is used to determine the relative position of each embedded part using a theodolite, and the elevation of each foundation is determined with a level. The elevation error does not exceed 3mm. And maintain the concrete foundation in a timely manner.
1.6 Preparations before installation
1) Before all auxiliary facilities and complete sets of mixing station equipment are transported to the site, the boiler regulations determine the mutual positions of the assemblies based on the installation foundation map, and it is particularly important to ensure that they are lifted into place at one time during installation. Otherwise, Repeated transport of equipment by crane on site will result in an additional increase in shift costs.
2) The installation site should meet the requirements and achieve “three connections and one level”.
3) Organize an experienced installation team to enter the construction site and organize and purchase installation equipment.
4) Installation sequence: Mixing building host machine – drying cylinder – powder machine, aggregate elevator – bag dust collector – cold extraction – finished product warehouse – control room – wiring.
2 Debugging of asphalt station
2.1 Conditions for debugging and production stages
1) The power supply is normal.
2) Fully equipped production and maintenance personnel enter the site.
3) Calculate the amount of thermal oil used in each part of the mixing station, and prepare various lubricating greases.
4) Reserves of various raw materials for the production of asphalt mixture: fuel, asphalt, and sand, stone, and stone powder that meet specification requirements.
5) Laboratory and inspection instruments required for on-site acceptance of equipment.
6) Contact the local Quality and Technical Supervision Bureau to calibrate the measurement system, floor scale, etc.
2.2 Pressure test
Mainly includes external heat transfer oil pipes, external asphalt pipelines, heat transfer oil pipes in asphalt storage tanks, and various connecting gas pipelines. Each of the above systems should be pressure tested separately to ensure that each system can withstand a pressure of 0.8-1MP and that there is no leakage or leakage in each connection. Otherwise, asphalt and thermal oil will mix in the double-layer pipeline, which will cause very large economic losses.
2.3 Fill oil into the thermal oil circulation system
1) First open the valve and blow air into the system with an air compressor to blow away the water or debris in the system. Otherwise, after filling the thermal oil, the water content will be too large, which will increase the dehydration time or the debris will be removed. It will affect the heat transfer efficiency and the service life of the heat transfer oil, and it is easy to damage the heat transfer oil circulation pump.
2) Start the main oil pump to inject oil into the circulation system, while watching the liquid level indicator. When the height is less than 2/3, stop oil injection, start the heat transfer oil circulation pump, and repeat this process until the system is completely filled with heat transfer oil.
3) Thermal oil is heated and dehydrated
(1) Cold cycle starts the heat transfer oil circulation pump to make the system perform cold cycle and fully exhaust the circulation system.
(2) Ignite the oil furnace to operate normally, and set the temperature to 105°C-120°C to dehydrate the heat conductor. The heating rate should not be too fast, generally no more than 20℃ per hour. When the temperature reaches the set temperature, turn off the flame and stay for a period of time (depending on the situation) to dehydrate the exhaust gas. Repeat this several times. Set the temperature for the second time to 180℃-200℃, then ignite it. When the temperature rises to the set temperature, stay there for a period of time in order to remove a small amount of light components in the heat transfer oil.
When starting the ignition, start the circulating pump first, and then ignite after it is normal. When shutting down, you must first stop the fire, and the circulating pump continues to run. Stop the pump when the oil temperature drops below 100°C.
2.4 Debugging of asphalt mixing station host
The quality of the main engine debugging is the prerequisite for the production of asphalt mixture. Therefore, the debugging of the mixing building is the central task of the overall debugging of the entire asphalt mixing station. Debugging content mainly includes the following items:
(1) Debugging of cold grading machine.
(2) Debugging of vibrating screen frequency.
(3) Adjustment of the verticality of the aggregate hoist.
(4) Adjustment of the dryer burner, that is, the air-to-oil ratio of the burner
(5) Debugging of bag dust removal mainly involves the relationship between the set values ??and actual values ??of the inlet and outlet temperatures, and the circulation system for cleaning each bag.
(6) Debugging of aggregate scale, powder scale and asphalt scale.
(7) Setting of weighing and stirring cycle time, adjustment of the up and down stroke of the trolley, and setting of the trolley unloading time
2.5 Acceptance of asphalt mixing station
The following requirements should be met (first the raw materials are qualified):
(1) The oil-stone ratio error shall not be greater than 0.3% (approved based on the accuracy of electronic measurement).
(2) The gradation of the mixture shall be judged after laboratory extraction and screening, and shall comply with the standard gradation requirements.
(3) When the moisture content of the stone is 5%, it can be continuously produced at the rated productivity.
(4) Low pollution, the dust emission in the atmosphere is required to be less than 200mg/m3.

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    More Asphalt Processing

    Now on the construction site, including in some engineering construction, one of the equipment used is asphalt mixing plant. It can be said that it can be used in many ranges and fields, and it can provide certain help for my country’s infrastructure construction. Of course, in the process of use, it is necessary to do a good job in many aspects, so that the use of mixing plant can be safer and more worry-free.
    1. Maintain standardized operating procedures
    In fact, it is not only in the use of asphalt mixing plant, but also in the use of other equipment. It should be done well. It can be said that this mixing plant will also have certain dangers. If there is any carelessness, it may also cause great losses. Therefore, at this time, it is still necessary to pay attention to the correct specifications and follow the process step by step. Only in this way can it be used safely and other use problems can be effectively avoided.
    2. Adjust the reasonable mixing ratio
    In the application of asphalt mixing plant, the most important and core step is the mixing. The mixing ratio of raw materials should be within a reasonable range and completed according to actual needs. Do not add or reduce raw materials at will according to your own wishes. Such operation is not standardized. In addition, after making a good ratio, you should also pay attention to safety protection measures during operation.
    Asphalt mixing plant still plays an important role. If you want to make the use of the mixing plant safer and more worry-free, you should pay more attention when using it and have a certain understanding of these precautions. Only in this way can you ensure that there will be no other problems in use and ensure the safety of the mixing plant.

    The asphalt mixing equipment mentioned here may also refer to an asphalt concrete mixing plant. At present, asphalt mixing equipment generally uses a complete set of equipment for mixing. So what are the benefits of using a complete set of equipment?
    1. More effective.
    In today’s industrial production, a complete set of asphalt mixing equipment can help improve production efficiency and ensure product quality. This is why even in a mixing plant, the equipment used is a complete set of equipment.
    2. Ensure quality.
    When mixing asphalt, a certain ratio is set. For this type of asphalt liquid used in different occasions, its ratio control has strict requirements. It is necessary to determine its mixing method and mixing time to ensure that the asphalt liquid is consistent with the production site. One of the advantages of a mixing plant is that the quality can be effectively controlled.
    3. It can be sampled.
    After mixing at the mixing plant, the quality inspector can sample and inspect to ensure that the mixed asphalt liquid meets the use requirements.
    In short, asphalt mixing equipment will use a complete set of equipment, mainly to facilitate the later asphalt to meet production needs. Through the mixing plant, the mixing time and feeding sequence can be better controlled, so that the mixed product can meet different use requirements. And after using the archiving equipment, effective spot checks can be carried out, which can better ensure that the quality meets the construction requirements.

    The renovation of the combustion-supporting system of the asphalt mixing plant and the use of DC frequency conversion CNC machining technology are all renovations of the original system. In addition to the above renovation plans, with the existing equipment and personnel, what other measures can be taken in the application to reduce the operating costs of concrete mixing plants?
    At present, China has no mandatory national industry standards for heavy residual oil, and the quality of fuel oil varies greatly. Even from the same dealer, the quality difference between batches is very large, and it contains more residues. Therefore, bridge inspection equipment should be installed on the construction site, and professional personnel should inspect various performance parameters of gasoline and diesel to strictly control quality.
    When the burner is working, if the flame of the combustion aid is red and the smoke from the ash removal chimney is black, this is the manifestation of poor atomization of gasoline and diesel and insufficient combustion aid. At this time, the following measures should be taken to deal with it: properly adjust the distance between the nozzle and the vortex plate, generally push it inward to a suitable distance, the purpose is to prevent the atomized oil cone sprayed from the nozzle from spraying into the vortex plate; effectively adjust the ratio of gasoline and diesel to gas, so that the gasoline and diesel increase the mass conversion law slowly, or the gas increase the mass conversion law quickly; promptly remove the carbon deposits and coke around the nozzle to prevent the flame from deflecting; heavy residual oil contains more residues, which can easily cause serious damage to the high-pressure oil pump and increase the working pressure, affecting the actual effect of atomization and the shape of the flame, so the high-pressure oil pump must be repaired or replaced in time; install metal filter devices in front of the first and second high-pressure oil pumps, and clean them frequently to prevent the residues in the gasoline and diesel from blocking the nozzle.
    The operators should be trained in professional skills on a regular basis to strengthen their job responsibilities and moral education, so that they can establish their respective job responsibilities, understand the importance of their positions, understand the content of their work, and improve their professional level. Skilled operators can properly control the temperature of the asphalt mixing plant mixture to avoid gasoline and diesel waste.
    In order to improve the combustion-supporting effect and effectively reduce the operating costs of asphalt mixing stations, Sinoroader Group kindly reminds that the following issues should be noted when using the burner in the asphalt mixing station: To improve the maintenance of the burner, the burner nozzle should be cleaned of charred materials and carbon deposits on the ignition electrode regularly. The nozzle can be disassembled according to the atomization status; the air-oil ratio of the burner is generally not adjusted, and the fuel pump pressure can be adjusted according to the smoke status and the temperature of the asphalt mixture; the sulfur dioxide generated by the combustion of light fuel oil has a strong corrosion to the bag, so the bag should be maintained regularly and the air pressure changes in the bag should be paid close attention to; water deashing will produce more foam, causing the sand settling tank to flow out, so the sand settling tank should be cleaned in time, and a watering design should be carried out to settle the foam; when the steam pressure decreases or the gear oil pump noise increases, the gear oil pump must be replaced.
    When the burner is started, the fuel oil circulation system should be completed through the valve, and then the burner control box should be opened to start the burner. If the electronic ignition of the fuel oil fails, you can change the inlet tee and use the diesel engine for ignition. After the ignition is successful for 2 minutes, you can convert it into fuel oil. In this way, even the light fuel oil of lower quality can ensure combustion.