Aerogel Felt as an Energy-Saving Insulation Material in Thermal Pipeline Applications
Table of Contents
Description of Thermal Pipeline
A thermal pipeline refers to the heating pipes that extend from boiler rooms, direct combustion engine rooms, heating centers, etc., transporting heat from heat sources to the thermal entry points of buildings. Multiple heating pipes form a network. With economic development and the promotion of centralized heating policies, the area covered by centralized heating will continue to grow. Such an extensive heating pipeline network requires a robust insulation system to ensure energy efficiency and safety during transportation.
The heating pipelines from the heat source plant to the thermal users are divided into primary and secondary networks. The primary network comprises heating pipelines from the heat source to the thermal station, while the secondary network encompasses pipelines from the thermal station to the thermal users. Typically, the primary network has diameters ranging from DN500 to DN1000, while the secondary network has smaller diameters ranging from DN125 to DN300.
The installation methods for heating pipelines generally include underground and aboveground methods. Underground installation includes trench and direct burial methods, while aboveground installation involves overhead placement. The primary network has a supply water temperature of 120-150°C, with a return water temperature of 70-90°C. The high water quality of the primary network significantly influences the effectiveness of insulation, impacting both the heating efficiency and the economic benefits of thermal operations.
Current Insulation Materials and Existing Issues in Thermal Pipeline Networks
Currently, centralized heating pipeline insulation layers predominantly use materials such as rock wool and glass wool. Rock wool is an inorganic fiber made from natural rocks like basalt and pumice through melting and fiberizing. Glass wool, on the other hand, is an artificial inorganic fiber produced by melting materials like limestone, quartz sand, and dolomite into glass, which is then fiberized and processed with a binder.
The use of rock wool and glass wool materials poses several issues:
Poor Stability: After installation, the initial effectiveness meets design requirements. However, after several months of operation, radiative heat loss increases, leading to the gradual failure of the insulation layer. The soft nature of materials like rock wool and glass wool, relying on binders for cohesion, makes them susceptible to failure as the binders degrade over time. Additionally, vibrations caused by hydraulic shocks and pressure fluctuations in the pipeline result in material settling, creating an uneven layer. This settling can lead to gaps between the pipeline and the insulation layer, promoting convective heat exchange, which increases radiative heat loss.
Corrosion Under the Insulation Layer: The porous structure of rock wool and glass wool materials allows moisture to penetrate. When moisture infiltrates the insulation layer and reacts with the pipeline walls, oxidation occurs, leading to corrosion and leaks. Even glass wool materials treated for hydrophobicity cannot withstand long-term use in high-temperature and high-humidity trench environments.
Short Lifespan: Due to the rapid degradation of traditional insulation materials like rock wool, frequent replacement is necessary. Aging leads to increased heat loss, higher maintenance costs, and elevated safety risks, with replacements required every 3-4 years.
According to statistics, network losses in centralized heating processes can account for up to 5% of the total thermal production. The significant impact of poor insulation on network radiative losses necessitates the use of superior insulation materials to reduce energy losses, decrease coal and gas emissions at the source, and provide positive economic and social benefits.
Advantages of Using Aerogel Felt in Thermal Pipeline Networks
