Solar groove type thermal power generation evacuated collector tube and preparation method thereof

Abstract

The invention discloses a solar groove type thermal power generation evacuated collector tube and a preparation method thereof. An annular circular tube is arranged between the Kovar metal and the inner tube of the collector tube, cooling water from condensate pump passes through the annular circular tube so as to cool the connection part between the end part of the inner tube and an outer tube, and simultaneously, temperature-raised cooling water is transported to a deaerator; an annular heat-shielding cover is arranged on the outer surface of the Kovar alloy so as to protect the Kovar alloy; and an expansion joint is arranged at the middle position of the inner tube, and a selective coating is also coated on the surface of the expansion joint. The method comprises the following steps: preparing a sylphon bellows, the Kovar alloy, a cooling drivepipe, the inner tube and the outer tube; welding the inner tube; welding the cooling water tube with the inner tube; sealing the Kovar alloy; annealing the sealing position; fixing a heat-shielding ring; and carrying out vacuum degassing. According to the invention, the problem that high temperature solar collector tube glass is sealed with metal is well solved, and process is simple and reliable, and has strong practicability.

Description

technical field [0001] The invention relates to a vacuum heat collecting tube for solar trough thermal power generation and a preparation method thereof, which belongs to the field of thermal energy and power engineering. Background technique [0002] The high-temperature vacuum heat collector tube is the core component of solar trough thermal power generation. The vacuum heat collector tube of solar trough thermal power generation is generally composed of an inner tube and an outer tube. It is a glass tube with high solar transmittance and low absorption rate. The inner and outer tubes are required to be evacuated to reduce convective heat loss. In the working state, the temperature of the inner steel pipe is much higher than that of the outer glass, and the expansion is also large. In order to eliminate this expansion difference, an expansion joint is usually set on the outer pipe or the inner pipe. . Due to thermal stress (high temperature can reach higher than 200°C) i...

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Problems solved by technology

[0005] At present, in order to eliminate the expansion difference caused by the difference in temperature and material of the inner and outer tubes for trough-type thermal power generation vacuum heat collectors, the technology adopted is to eliminate the expansion difference by setting bellows on the inner tube or outer tube, and the inner tube temperature Higher, the heat is transferred through the connecting piece, resulting in a higher temperature of the connecting piece, the technology adopted is to develop Kovar alloy to withstand the thermal stress caused by the temperature difference, and there is also a protective device to prevent the radiant heat gathered by the concentrating groove, These methods can reduce thermal stress or thermal expansion to a certain extent, and are very reliable in mid-low temperature solar trough heat utilization, but in trough thermal power generation, if the main steam temperature exceeds 400°C, the existing Kovar alloy will suffer The capacity often fails to meet the requirements. In addition, Kovar metal can become a thermal bridge, which quickly transfers the heat of the inner tube, resulting in a certain amount of heat loss, which cannot meet the commercial competitiveness of high-temperature, high-pressure tank-type thermal power generation with high reliability. And the requirements of changing working conditions, the object of the present invention is to provide a solar trough thermal power generation system, heat collecting tube and preparation method thereof for the defects existing in the prior art

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