Related Experiment Video
Updated: May 13, 2025

Measurements of Local Instantaneous Convective Heat Transfer in a Pipe - Single and Two-phase Flow
Published on: April 30, 2018
Research on the Resourceful and Efficient Recycling Technology of Waste Thermal Insulation Pipe Material
Xiaohua Gu1,2,3, Qinglong Zhao4, Shangwen Zhu1
1School of Energy and Building Environment, Guilin University of Aerospace Technology, Guilin 541004, China.
Abstract:
This study was conducted to explore a new method for degrading and recycling waste chemical pipe insulation and cooling materials. A chemical degradation method was employed, utilizing alkali metal catalysts and a two-component alcoholysis system consisting of specific ratios of diethylene glycol and butylene glycol. The system effectively degraded the polyisocyanurate (PIR) insulation with the aim of reusing the waste material. The experimental results show that the best reaction performance is obtained with 1,4-BG/DEG ratio of 43:57 at 180 and 190 °C 1 h. The resulting regenerated pipe has an apparent density of 0.041 g/cm3 and a compressive strength of 0.413 MPa. With remarkable thermal stability, well-preserved porosity, and strong skeletal structure, the cold loss on the outer surface of the insulated pipe is lower than the design requirement of 23 W/m2, which is qualified for the energy efficiency of the insulated pipe. The proposed strategy for degradation and recycling of waste chemical pipe insulation and cold insulation materials provides a pioneering green treatment method for the task of recycling polyurethane waste with fire-resistant degradability and a high cross-linking degree.
Related Concept Videos
Thermal Insulation in Masonry Walls
External insulation can be applied using an Exterior Insulation and Finish System (EIFS), which involves affixing panels of plastic foam to the wall and covering them with a polymeric stucco reinforced with glass fiber mesh....
Multiple Pipe Systems
Series Configuration
In a series configuration, fluid flows sequentially from one pipe...
Single Pipe Systems
In a Type I problem, fluid properties (density and viscosity), pipe characteristics (including diameter, length, and surface roughness), and the flow rate or average velocity are...
Minor Losses in Pipes
Valves play a significant role in generating minor losses by obstructing or redirecting the fluid flow. When a valve is closed or partially closed, it restricts the flow...
Thermal expansion and Thermal stress: Problem Solving
To solve the problem, first, identify the known and unknown quantities. The initial length (L) of the bridge is 1275 m, the coefficient of linear expansion (α) for steel is 12 x 10-6/°C, and the change in...
Conduction, Convection and Radiation: Problem Solving
In order to solve a problem related to heat transfer, first of all, the situation needs to be examined to determine the type of heat transfer involved. This could...

