Utility boiler heating surface design method applicable to flue-gas temperature deviation fixation

A flue gas temperature, power plant boiler technology, applied in the direction of combustion method, boiler water pipe, lighting and heating equipment, etc., can solve the problems of uneven flow, different pressure difference of parallel pipes, uneven heat absorption of pipes, etc.

Active Publication Date: 2013-08-14
SHANGHAI BOILER WORKS
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0005] 2) The flame is poorly filled in the furnace, or the center of the flame is deflected
[0006] 3) Local slagging or dust accumulation on the heating surface will cause serious uneven heat absorption between the tubes
[0009] (2) In terms of uneven flow:
[0011] 2) The connection between the header and the inlet and outlet pipes is different, which causes the pressure difference between the two ends of the parallel pipes to be different, resulting in uneven flow

Method used

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  • Utility boiler heating surface design method applicable to flue-gas temperature deviation fixation
  • Utility boiler heating surface design method applicable to flue-gas temperature deviation fixation
  • Utility boiler heating surface design method applicable to flue-gas temperature deviation fixation

Examples

Experimental program
Comparison scheme
Effect test

Embodiment

[0035] Example: In the horizontal flue, take 8 screens as an example, assuming that each screen has the same size and material, and the way of introducing and leading out of the header is the same.

[0036] The first step is to determine the flue gas temperature deviation coefficient of each screen according to the flue gas side temperature deviation curve on the same section;

[0037] like image 3 Shown is a schematic diagram of the temperature deviation curve on the flue gas side. In addition, in order to facilitate understanding, a table is imagined below, and the approximate data is put into the table.

[0038] Table 1

[0039] Location Screen 1 Screen 2 Screen 3 screen 4 Screen 5 Screen 6 Screen 7 Screen 8 Flue gas temperature ℃ 1120 1130 1150 1125 1105 1120 1150 1100 Flue gas temperature deviation coefficient α 0.9956 1.0044 1.0222 1 0.9822 0.9956 1.0222 0.9777

[0040] As shown in Table 1, the average temperatu...

Embodiment 2

[0068] Embodiment 2 is the same as the first three steps of embodiment 1. After obtaining the comprehensive deviation coefficient, improve the material grade of the screen with large deviation to resist the possible deviation. This method does not eliminate the actual deviation, but the personalized design can ensure a certain degree of safety while ensuring safety. economy.

[0069] The fourth step is to adjust the material selection of the heating surface and design the deviation screen by calculating the coefficient of the flue gas deviation on the same section and the steam deviation between the screens. The screen with a large deviation can choose a good material, and the screen with a small deviation can be slightly inferior.

[0070] As shown in Table 4, if the comprehensive deviation of the screen is less than 1, it is a negative deviation, and if it is greater than 1, it is a positive deviation. Whether it is a positive deviation or a negative deviation, the greater t...

Embodiment 3

[0073] Embodiment 3 is the same as the first three steps of Embodiment 1.

[0074] The fourth step, after obtaining the deviation coefficient, we can adjust the design resistance of each screen through the size of the opening on the header, so as to adjust the flow rate of each screen to offset the difference caused by the deviation of flue gas and steam. The deviation between the screens is formed to obtain a more uniform outlet temperature.

[0075] like Figure 4 As shown, the working fluid enters the inlet header 1 from both ends, and a hole is opened on the header, and a pipe joint 3 is welded on the hole, and the pipe joint 3 is connected to the pipe 4 on the heating surface. The opening is large, and the inner diameter of the pipe joint is correspondingly large. The working fluid enters the outlet header 2 after being heated on the heating surface, and flows out from both ends of the outlet header. When the opening becomes larger, the inner diameter of the pipe joint...

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Abstract

The invention discloses a utility boiler heating surface design method applicable to flue-gas temperature deviation fixation. The utility boiler heating surface design method includes firstly, determining a flue-gas temperature deviation factor of each screen according to flue-gas side temperature deviation curves on the same fracture surface; secondly, determining steam deviation curves according to a given dimension of a collecting box and introduction and eduction manners of a heating surface pipe from the collecting box to acquire a steam deviation factor of each screen; thirdly, performing superposition to the flue-gas temperature deviation factor and the steam deviation factor to acquire a comprehensive deviation factor of each screen; and fourthly, according to the comprehensive deviation factor of each screen and under the circumstance of unchanged gross heat-absorbing quantity of each heating surface, adjusting design resistance of each screen by adjusting the size of an opening on the collecting box to adjust working medium flow of each screen to offset compressive deviations among screens formed by flue-gas temperature deviations and steam deviations so as to enable steam outlet temperature of each screen to be uniform.

Description

technical field [0001] The invention relates to the field of boiler equipment, in particular to an optimized heating surface design method suitable for flue gas deviation fixation. Background technique [0002] There are thermal deviations in the heating surfaces of utility boilers. Thermal deviation refers to the phenomenon that the enthalpy increase of the working fluid of each tube in the parallel tube group is different. The degree of thermal deviation can be expressed by the thermal deviation coefficient, which is the ratio of the enthalpy increase of individual tubes in parallel tubes on the heating surface to the average enthalpy increase of parallel tubes. A ratio of 1 indicates no deviation; a ratio greater than 1 indicates a positive deviation, that is, the enthalpy increase is too large; a ratio less than 1 indicates that the enthalpy increase is too small. The thermal deviation of the heating surface is caused by the uneven flow direction on the working fluid s...

Claims

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Application Information

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IPC IPC(8): F22B37/10F23M5/08
Inventor 姚丹花
Owner SHANGHAI BOILER WORKS
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