Method for preparing anticorrosive paint for directly-buried thermal power pipeline insulating layer

Abstract

The invention discloses a method for preparing an anticorrosive paint for a directly-buried thermal power pipeline insulating layer. The anticorrosive paint comprises deionized water, propylene glycol, a dispersing agent, a wetting agent, an antifoaming agent, a corrosion inhibitor, a coupling agent, a ceramic fiber, a needle-shaped crystal whisker, titanium dioxide, heat insulation powder, platy fillers, modified water-dilutable resin emulsion, a film-forming addictive, a hollow microsphere, a flatting agent and a thickening agent. The method comprises the following steps of: putting the materials into a dispersing tank in several times and in batch; and stirring the mixture at different rotation speeds so as to prepare the anticorrosive paint. The anticorrosive paint does not crack or drop for a long time at the temperature of 150 DEG C when heat conduction coefficient is up to 0.040W/m.k and a hemisphere emissivity is up to 0.87-0.89. The anticorrosive paint is high in physical and mechanical properties of infrared radiation capability, fracture elongation ratio, adhesive force and the like, is good in water resisting property and is low in water absorption ratio, so that moisture absorption and water seepage are prevented under the underground environment, corrosion of pipelines is avoided, and the requirement of the insulating layer in the directly-buried laying thermal insulation technology is met.

Description

technical field [0001] The invention belongs to the technical field of heat preservation and anticorrosion coatings, and in particular relates to a method for preparing an anticorrosion coating for direct-buried thermal pipeline insulation layers. Background technique [0002] Due to the rapid increase of urban central heating pipe network system and the increase of transmission distance, it is an inevitable trend of development to increase the temperature of hot water in the heating pipe network from the previous 130°C to 150°C. [0003] The pipeline layout of the heating pipe network system is divided into three types: overhead laying, trench laying and direct buried laying. The pipes of the heating pipe network system are all equipped with insulation layers. The purpose of insulation is mainly to reduce the heat loss of heat medium during transportation, save fuel, ensure the safety of operators, improve working conditions, and ensure the use temperature of heat medium. ...

AI Technical Summary

Problems solved by technology

[0004]The thermal insulation technology of direct burial laying is composed of high-density polyethylene outer protective layer, thermal insulation layer and steel pipe. The gap between them, and has a certain bonding strength, so that the steel pipe, the outer casing and the insulation layer form a solid whole. The insulation layer generally uses polyurethane with a density of 60-80kg / m3 Foam, the polyurethane foam has an extremely low thermal conductivity of 0.019-0.028 W / m k, and the use of polyurethane foam for insulation can reduce about 90% of heat loss. It is currently the most commonly used and most economical insulation layer, but ordinary polyurethane foam The upper limit service temperature of the material is 130°C. When working in a high temperature environment above 150°C for a long time, its aging speed will be accelerated, and even carbonization will occur, resulting in a decrease in the strength and thermal insulation performance of the insulation layer

[0005] In addition to polyurethane foam as insulation layer, aluminum silicate fiber, rock wool, glass wool, ceramic fiber, etc. are also used as insulation layer. It is necessary to use auxiliary material package for winding and reinforcement during construction. The insulation layer is thick, the adhesion to the base material is poor, and the water absorption rate is high. It is easy to cause safety hazards caused by corrosion. The service life is short and the construction is inconvenient.

[0006] In addition, inorganic thermal insulation coatings can also be used as insulation layers. The disadvantage is that the coatings are almost rigid and hard, without toughness, and the coating layer is hard. But brittle, the mechanical properties of the coating layer are poor, not resistant to vibration, easy to crack, pulverize, peel off, poor adhesion to the substrate, heavy metals and other harmful substances and volatile VOC content, short service life, etc., cannot meet the requirements of heating pipes. Network system environmental protection, energy saving and consumption reduction requirements

[0007]Ordinary polyurethane insulation layer can no longer meet the needs of actual projects in the future. In order to prevent ordinary polyurethane from aging or even carbonization at high temperatures above 150°C for a long time, a resistant Higher temperature heat insulation materials can not only reduce the temperature to below 130°C, but also can withstand high temperature aging at 150°C for a long time, which meets the current insulation structure