Currently, the unit capacity of thermal power plants is constantly increasing with the development of society, and the boiler capacity is also increasing. At the same time, there have been significant changes in furnace walls, pipeline insulation structures, thermal equipment, materials, etc. With the continuous development of science and technology in our country, new insulation and refractory materials, new processes, and new structures have begun to appear in large quantities in the market. However, in recent years, there have been many problems in the construction process of the project, which seriously affect the quality of the project, and therefore urgently need to be solved.
1. Problems in construction
1.1 Problems with refractory materials
Choosing the same material in different places, due to the relatively single variety of materials selected, the performance of refractory materials is not fully utilized, which to some extent leads to resource waste. Using the same construction methods and techniques in different construction environments not only fails to adapt to local conditions, but also the advantages of the materials themselves are not well reflected. For example, in some door opening boxes, fire-resistant ramming materials are designed to be used, which brings great inconvenience to construction. In addition, in the process of material selection and design, excessive emphasis is placed on the fire resistance and strength indicators of the materials, while ignoring the special requirements of special parts.
1.2 Problems with insulation materials
The problems with insulation materials mainly include the following aspects: firstly, in the process of selecting materials for designing furnace walls, insufficient consideration is given to the factors affecting the thickness of the insulation layer, resulting in a low thermal conductivity. The thermal conductivity of materials is generally obtained through experiments, but the insulation materials used in practice are of varying quality. The materials used in construction do not have refined performance testing methods, and only achieve visual inspection and acceptance; Secondly, in practice, the temperature of furnace walls in some projects is too high, which is closely related to the tightness of the metal primary seal. However, there are also issues with the thickness of the insulation layer and the selection of insulation materials; Thirdly, insulation materials can cause certain harm to the skin of construction workers. At the same time, due to the lack of scientific and reasonable evaluation of material performance and price, many new insulation materials excessively exaggerate their insulation performance in the promotion process, resulting in prices much higher than traditional materials; Fourthly, many new insulation materials adopt traditional construction techniques and neglect the design of construction techniques; Fifth, insufficient consideration was given to the problems that existed during construction, and many advanced construction techniques and experiences were not fully reflected in the design, resulting in a disconnect between design and construction; Sixth, insulation engineering has the characteristics of short time, labor-intensive, and large workload, so it is difficult to achieve reasonable coordination for the relief during construction.
Two suggestions for the design of refractory insulation materials in thermal power plants
2.1 Suggestions for refractory material design
Firstly, the design variety of refractory materials for the same project should not be single, but it should not be too complex. The selection of refractory materials that can meet the requirements should be based on different temperature regions and usage requirements. On the basis of economy, fully utilize the performance of refractory materials to achieve full utilization of resources; Secondly, in the refractory sealing project of the furnace ceiling, due to the short construction period and poor construction conditions, high-temperature micro expansion refractory plastic should be changed to fast hardening boiler sealing refractory pouring material or clay super strong pouring material in the design process. This is mainly due to its high strength, short solidification time, and small shrinkage, which can improve the sealing of the furnace wall and reduce heat loss; Again, using high-temperature micro expansion refractory plastic lining in the combustion area of the boiler can improve the refractory effect; Finally, due to the high performance requirements of unburned belts and burners for refractory materials, high aluminum phosphate combined with plastic, silicon carbide ramming materials, and silicon carbide high aluminum coating materials can be used.
2.2 Suggestions for insulation material design
Firstly, in insulation engineering, new materials, processes, and structures should be used as much as possible. At the same time, economic comparison and analysis should be conducted during the material selection process. Insulation materials with good insulation effect, high performance, reasonable price, and easy construction should be used to save resources as much as possible; Secondly, when calculating the thickness of the insulation layer, reasonable exploration and improvement should be made to the parameters in the calculation methods and methods. The thermal conductivity coefficient should be scientifically determined to avoid surface temperature exceeding a reasonable range. The physical and chemical performance indicators of materials should be tested by national authoritative institutions; Thirdly, the design department and personnel should have a thorough understanding and mastery of the problems that exist on the construction site, and pay attention to the feedback information from the construction and make timely improvements; Fourthly, in the design process, corresponding new processes should be adopted based on the properties of new materials, and reasonable improvements should be made to outdated or unsuitable structures, in order to develop a new scientific structure; Fifthly, based on the actual engineering situation, comprehensive consideration should be given to the structure and material selection of certain equipment, not only to ensure the appearance is beautiful, but also to ensure the insulation effect; Sixth, due to the special properties of some furnace walls, semi hard materials should be used as much as possible for insulation, and soft or brittle materials should not be used; Seventh, for thermal equipment and pipes subject to frequent vibration at high temperature, microporous silicic acid insulation materials should not be used. When elastic soft materials, such as foam asbestos, are used for retaining walls, the thickness of the insulation layer needs to consider the compression properties of the materials. The corners of the protective wall can be directly wrapped; Eighth, for certain equipment, such as air ducts, smoke ducts, etc., due to their density and high reinforcement bars, when the thickness of the insulation layer is thin, materials with less elasticity and soft texture should be used. When the insulation thickness is thick, hard or semi hard materials can be used internally, and soft materials can be used externally; Ninth, strictly control the quality of materials, prioritize the use of materials for public bidding, and relevant leaders should scientifically and reasonably reduce administrative intervention; Tenth, materials need to be inspected in batches and carefully accepted. Materials that fail the inspection are strictly prohibited from being used; Eleventh, measures should be taken above the material to prevent rain and snow from affecting the insulation effect due to moisture; Twelfth, according to the characteristics of insulation engineering, it is necessary to increase the supervision of intermediate links, strictly control the quality, and reasonably coordinate the construction materials, construction, and construction supervision.
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