Setting and commissioning scheme of safety valve o

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Boiler safety valve setting and commissioning scheme

2. Purpose of safety valve setting

safety valve is an important protective device to prevent boiler overpressure and protect the safe operation of boiler unit. According to the provisions of the boiler supervision regulation for electric power industry on the substantial improvement of heat resistance and oil resistance: after the maintenance of the safety valve and before putting into operation, the safety valve must be adjusted and verified in hot state to ensure the safe operation of the boiler. In this transformative overhaul, a total of 8 safety valves for saturation, overheating and reheating of the boiler have been disassembled and grinded, so the above 8 safety valves need to be calibrated

after all safety valves have been calibrated by the oil pressure jump aid, in order to check the correctness of this safety valve calibration, the superheated safety valve on side a is selected for the real jump test. In order to prevent the safety valve from refusing to move and not returning to its seat after the safety valve is started, the operator should strengthen the monitoring and control of the main steam pressure and drum water level, and the operator should prevent the superheater and reheater pipe wall from overheating

3. Debugging object

#2 furnace: hg-420/13.7-ym1, the design parameters are as follows:

#8226; Superheated steam flow d1=420t/h

8226; Superheated steam pressure p1=13.7mpa

#8226; Superheated steam temperature t1=540 ℃

8226; Reheat steam flow d2=341.23t/h

8226; Reheat steam pressure p2=2.645/2.450mpa

#8226; Reheat steam temperature t2=326.49/540 ℃

8226; Boiler feed water temperature tgs=247.93 ℃

; The drum pressure p=14.97mpa

has rich experience and improved the national standards and relevant industry specifications of China's seismic isolation technology 8226; design efficiency η= 91.79%

this boiler adopts a total of 8 full volume spring safety valves produced by Harbin Boiler Factory. Among them, the primary steam system has 4 safety valves (2 steam drums and 2 superheater headers). There are four safety valves in the secondary steam system. (2 at the inlet of low pressure reheater and 2 at the outlet of high pressure reheater)

4. The setting method of safety valve

4.1. The setting value of safety valve calibration action pressure is determined in accordance with the "supervision regulations for electric power industry boilers", and the calibration method refers to the product instructions of safety valve manufacturers

safety valve setting values are shown in the following table:

number of safety valve positions, starting pressure, reseating differential pressure

drum (a) 115.755%

drum (b) 116.27%

superheater header (a) 114.394%

superheater header (b) 114.84%

low Re inlet (a) 12.885---7%

low Re inlet (b) 12.925---7%

.High re export (a) 12.675---7%

high re export (b) 12.685---7%

1.4.2 the safety valve is set by the verification method of oil pressure jump aid. At 75% - 80% of the rated pressure of the boiler (i.e. the surface pressure of the steam drum is MPa, and the pressure of the reheat cold end is 2..3mpa), Qinghai hengxinrong lithium production line with an annual output of 20000 tons of lithium carbonate was put into trial production in November 2017, and the safety valve was adjusted

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