Guazhou County,located in the western end of Hexi Corridor in Gansu Province,has an annual precipitation of less than 45 mm and evaporation of up to 3300 mm.The territory is windy and sandy,and the vegetation is sparse.The oasis area once was less than 15%of the county area.Guazhou area is known as the»wind field in the world».
The strong wind weather and high temperature environment have brought challenges to the overall construction of the 700,000kW»Solar Thermal Energy Storage+»project of Three Gorges Henderson Energy Pulse Guazhou County undertaken by the installation company.
As the world’s first»Two heat absorbing tower and One turbine»heat storage concentrated solar power project put into construction,and one of the first batch of large base construction projects approved by China National Development and Reform Commission and the National Energy Administration focusing on desert,gobi and desert areas,the project has been given higher design standards,construction difficulty and strict construction schedule.
The project adopts tower molten salt technology,the annual power generation can reach 180 million KWH,the project cost is 2.2 billion yuan,the installed scale is 2×50MW,supporting two 200-meter high heat absorption tower,a steam turbine generator set with rated power of 100MW,one high and low temperature molten salt storage tank,the selection of 29.7 square meters of rectangular heliostat nearly 27,000.On the 301-hectare construction site,there are 12 professional construction projects,including construction,mechanical and electrical installation,heat engine,electrical,automation,water supply,chemical water and HVAC,with a total of 449 volumes of design drawings.And the unexpected strong wind weather,repeatedly blocked the normal development of construction.
In the face of such a huge project,Gansu Installation and Construction Group gives full play to its professional construction advantages,insists on turning everything around the project and focusing on the project.It coordinates various professional branches and appoints various professional talents to set up the project headquarters,closely centering on the five key points of safety,quality,construction period,cost and excellence,forming the leading group to command and the project department to focus on.The efficient linkage work pattern of main construction of each engineering company and coordination and cooperation of business departments.The project department makes detailed goals,strategies,operating procedures and schedules,strengthens the management and deployment of materials,equipment and human resources,and implements the fine management to every node,every task,every post and every day to ensure that the construction is promoted on time and completed with high quality.
The heat absorder will absorb the sunlight reflected by the helistat,and heat the liquid binary molten salt at 280℃to the high temperature molten salt at 580℃to store the heat energy,which is one of the key components of the photothermal power generation system.The heat absorbing device with a height of 35 meters and a diameter of 15 meters will be installed at the top of the heat absorbing tower more than 165 meters above the ground.The total weight of the equipment and supporting facilities is 910 tons,and its lifting is the biggest difficulty in the construction of the project.Every step forward of the heat absorption tower,the time for the installation of the heat absorption device is more than a few minutes.In order to maximize the lifting time,the project management team thinks of ways to improve the speed,quality and efficiency of the construction of the heat absorption tower.
The construction of heat absorption tower is a super dangerous project.According to the actual situation of the construction site and the design requirements,the project department carefully analyzed and judged that the construction technology of»special construction lift+tripod support system+three layers of mold turn»was adopted,with fast speed,good quality,simple structure of machinery and tools,stable lifting,mature technology and good safety protection.It effectively eliminates the torsion,pull mark,drift and other common quality problems caused by sliding mold and lifting mold construction.More than 16,000 cubic meters of concrete need to be poured in the construction of the two towers.The control of concrete quality is an important part to ensure the construction quality.The project department strictly establishes the concrete mix ratio and quality standards,does a good job in the inspection of raw materials,the supervision of the production process and the test of concrete strength to ensure that the concrete has the required strength,liquidity and durability.In turn,the reliability and durability of the project are improved.
The design of two towers and two mirror fields and the use of a small area heliostat are two major features of the project,which can effectively improve the utilization rate of light and thus improve the efficiency of power generation.Heliostator system has large construction volume and wide area and high accuracy requirements.The vertical deviation of each prefabricated pipe pile must be less than 3 mm,and the deviation of central point coordinate should be controlled below 5 mm.The project department makes bold innovation in the construction of prefabricated pipe pile test pile,and repeatedly improves the construction technology and equipment through tests.Finally,before the formal construction,it develops a set of tooling that can control the deviation of verticality and center point within the design error range,overcomes the technical difficulties,and greatly improves the construction speed and accuracy.At a rate of 300 roots a day,the heliostat field is spread out at an accelerated rate of 296 hectares.
Under the harsh construction conditions of raging wind and scorched sun,the project department united and led more than 350 workers to rise to the challenge.In the face of strong wind,the project department regularly checked and maintained the stability and safety of the site equipment,fixed scaffolding and built temporary protective facilities in time.The project department purchased wind speed measuring instruments to strengthen monitoring and early warning,always pay attention to wind changes,once the wind reaches above level 5,immediately stop high operations and dangerous operations,to ensure the safety of operators.In summer construction,the project department avoids high temperature periods,reasonably arranges working hours,implements heat prevention measures in high temperature working environment,increases ventilation equipment,reduces the temperature of the operation area,provides sufficient drinking water and shading facilities to workers,and ensures the health of all personnel.
By the end of July,the heat absorption tower on the west side has been constructed to 120 meters,the heat absorption tower on the east side has been constructed to 115 meters,2,600 piles have been erected and poured in the mirror field,the basic civil construction of the molten salt storage tank has been completed,the helostat assembly workshop has been delivered,and the administrative office building has been capped.The project Department accelerates the overall construction progress,makes every effort to ensure the smooth realization of the grid-connected goal.