In Dajunling, Huadu District, Guangzhou, a garbage truck drives down a winding road into the mountains, quickly reaching the end of the Fifth Resources Thermal Power Plant, where it dumps its household waste into a garbage pond. "After the garbage is stacked and fermented for a period of time, it is then processed in multiple processes to finally generate steam to generate electricity for the generator set." The person in charge of the south China regional company of the first bureau of the project contractor was introduced.
At present, Guangzhou proposes "zero landfill" for domestic garbage, and the construction of garbage treatment facilities is particularly critical. The reporter visited the second phase of the fifth resource thermal power plant in Guangzhou, learned that after the project overcome many construction problems, it has recently been connected to the grid for power generation, and is expected to be completed and delivered next year, becoming an important force for Guangzhou to achieve "zero landfill".
The oversized garbage pond set a new construction record
Garbage pond construction
At the scene, robots reach into a huge garbage pool and grab the fermented garbage into the furnace to burn, while in the operation room, the staff monitors the data of the treatment process.
For waste incineration plants, the waste pool is a key project, and in the second phase of the project, this project is particularly large. The superstructure of the garbage pond is 144 meters long and 30 meters wide, and there is also an ultra-high concrete shear wall of 46 meters high and 800 mm thick, and the underground structure is 11.35 meters deep, and the total amount of steel reinforcement is more than 6,000 tons.
How to ensure the safety of the project and its completion on schedule? The project innovates in both management and technology. For example, for the ultra-high shear wall, the new mold frame support method is adopted, which also obtained the utility model patent "a scaffolding wall part suitable for ultra-high shear wall". In the specific construction, the single garbage pond is also divided into two "U-shaped" construction sections to achieve seamless construction flow and optimize the management cost and input of the project.
At the same time, the establishment of quality and safety red and black list and construction progress evaluation list, etc., the quality department took the lead in sharing and exchanging excellent practices, continuously optimizing construction technology, etc., to accelerate the construction of the project.
In the end, the cap was capped in advance with 100 days, which also refreshed the new speed of waste pool construction in resource thermal power plants. "The second phase of the project is equipped with two 50 MW steam turbine generator sets, and after the garbage is test-fired, the steam drive unit generated is officially put into operation." Introduction of the person in charge of the scene.
Garbage pool "hidden" without "leaking"
For a long time, the leakage problem of waste incineration plants has attracted wide attention, and it is also related to the quality of the ecological environment, how to make the garbage pond "hidden" without "leaking"? The person in charge of the scene said that it is to give the garbage pool "strong bones and bones, put on the armor."
The project team and experts have discussed many times and decided to change the post-pouring belt of the garbage pond to an expansion reinforcement belt, so as to avoid the risk of leakage in the later construction of the post-pouring belt.
Subsequently, through multiple tests to determine the optimal proportion of concrete, and increase the anti-crack fiber, reduce the risk of leakage of the garbage pool wall, and make the pool wall concrete crack situation much higher than the standard of the design code.
However, in practice, the junction of the construction joint is the weakest part of the garbage pool leakage, and once the anti-corrosion and waterproof material in contact with the garbage is destroyed, the strong corrosive leachate will directly invade the construction joint to corrode the reinforced concrete.
Garbage anti-corrosion and anti-leakage
In this regard, the project resolutely adopts 316L stainless steel. "Although the cost is higher, it is the best material to resist leachate, and construction standards need to be raised for safety and the environment." The project leader said that the vertical and horizontal construction seams of the pool wall structure are made of fully welded 316L stainless steel water-stop steel plate.
In addition, the waterproofing of the inner wall of the garbage pool adopts the osmotic crystallization of 5mm thick peng internal cementitious imported from the United States, which is integrated with the substrate to form a crystalline dense waterproof layer, just like armor. During the construction, the concrete base layer should be polished twice, and the high-pressure water gun treatment should be carried out 2 times to ensure that the osmotic crystallization can fully react with the concrete pool wall, while the anti-corrosion is made of 5mm thick and high wear-resistant epoxy glass scales, and the high-altitude hanging basket is used to improve the anti-corrosion effect.
Improved process to solve the 130-meter chimney problem
Walking into the site of the second phase of the project, you will see a building of hundreds of meters, which is another big project - the chimney, which is the key facility for the emissions of the power plant.
130m oversized landscape chimney
The chimney project of the second phase of the project is 130 meters high, because the chimney design concept is slightly different from the previous chimney of the waste incineration power plant. "Compared with the traditional 130-meter chimney, the amount of work is larger, and due to the deepening design of the sightseeing platform, the construction period is tight, the site is small, and the construction is difficult." Introduction of the project leader.
In order to avoid the traditional sliding die construction affecting the concrete forming quality and chimney stability, the project switched to the mold turning construction technology, and the truss platform load was transmitted to the lower concrete cylinder wall with a certain strength by means of sliding frame mold lifting, thereby achieving safe and efficient production.
At the same time, in order to improve the construction and appearance quality of the cylinder wall, before the external formwork is installed, a specific proportion of cement mortar is leveled on the top surface of the chimney to ensure the appearance quality of the cylinder and the loss of concrete as much as possible.
In addition, the construction also adopts the "UAV + tower crane machine + 5G" remote high-definition real-time monitoring management system to achieve the whole process without dead angle monitoring, visual communication between high-altitude and ground personnel, and ensure the safety of high-altitude work.
In the end, the chimney project began its first slide on December 13 last year, effectively shortening the construction period by more than 60 days.
Small sites and large hoisting accelerate people's livelihood projects
The construction of the second phase of the project has many contents, the site is relatively small, and the construction of large machinery is also a problem.
Taking the garbage pond as an example, the roof is composed of inverted triangular steel trusses, with a large area and a large amount of steel. During the construction process, the site overcame the problems of multi-process interspersed operation and narrow hoisting site.
The 400-ton crawler crane is used for steel structure hoisting operation, and the software is used to simulate the construction steps before hoisting, the optimal working conditions for hoisting are selected, and 2 hoisting station sites are reasonably designed.
"In order to make the people's livelihood project effective as soon as possible, the large-scale equipment has been increased from the original 6 to 11, and the station sites have been reasonably set up at the site." The project leader said that the second phase of the project has also become the first project in Guangzhou to complete the sealing of the steel structure of the roof of the garbage pond in the five thermal power plant projects under construction in Guangzhou.
The second phase of the project is expected to be delivered next year, and the next stage will be interior decoration, façade construction, etc., and cooperate with equipment commissioning to officially enter the trial operation stage. After the project is officially put into operation, the average daily treatment capacity of domestic waste will reach 3,000 tons, and the annual power generation capacity will reach 576 million kWh, helping Guangzhou to achieve "zero landfill" of primary domestic waste.
[Reporter] Zhang Zijun
[Correspondent] Lu Zhijie
【Author】 Zhang Zijun
【Source】 Southern Press Media Group South + client
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