CN101408954A - Method for evaluating boiler component probabilistic risk - Google Patents

Abstract

The invention relates to a probability risk evaluating method for boiler components. The probability risk evaluating method is characterized in that according to the failure probability, the average repair time, the failure result weight coefficient and the accumulated service life wastage of the boiler components, the risk taxis number of the boiler components is calculated in definite quantity, the risk of the boiler components in use is evaluated, and the risk control of the boiler components is instructed. The invention has the advantages that the probability risk of the boiler components is expressed in definite quantity by adopting the risk taxis number, and scheduled repairing is planned according to the risk taxis number of the boiler components, so as to lead the probability risk of the boiler components to be in a controlled state, and meanwhile, the technical effect of reducing the risk of blowing-out of the boiler components is also achieved.

Description

A kind of method for evaluating boiler component probabilistic risk

Technical field

The present invention relates to a kind of method for evaluating boiler component probabilistic risk, be applied to quantitative evaluation, belong to the boiler technology field the boiler component risk.

Background technology

Operational phase at boiler, can determine the statistics of boiler operatiopn reliability by the statistical study of service data, but also can't determine the evaluation result of boiler component probabilistic risk,, also not have suitable method available at present for the probabilistic risk assessment of active boiler parts.

Summary of the invention

The purpose of this invention is to provide a kind of a kind of method for evaluating boiler component probabilistic risk.

For realizing above purpose, technical scheme of the present invention provides a kind of method for evaluating boiler component probabilistic risk, it is characterized in that use parts risk ranking number to come the computing method of quantitative description boiler component probabilistic risk and the evaluation method of boiler component probabilistic risk thereof, its method is:

The first step: the evaluation object of selecting the boiler component probabilistic risk

Select some parts, certain several parts or several parts of boiler to carry out probabilistic risk assessment;

Second step: the evaluation cycle of boiler component probabilistic risk

The probabilistic risk assessment cycle of boiler component is taken as 2 years to 3 years, determines that according to the use year number of active boiler the evaluation cycle of boiler component probabilistic risk is illustrated in table 1;

[table 1]

Using a year number	The probabilistic risk assessment cycle
		The 1st year to the 18th year	3 years
The 19th year to the 30th year	2 years

The 3rd step: determine that boiler component causes the fault mode of blowing out

Use existing reliability statistics analytical technology can determine that boiler component causes the fault mode of blowing out;

The 4th step: the probability of malfunction FP that calculates boiler component _Ij

Program with the C language, operate in the computing machine, calculate i parts of boiler the probability of malfunction FP that the j kind causes the fault mode of blowing out takes place _Ij

${\mathrm{FP}}_{\mathrm{ij}}=\frac{8760\×{\mathrm{NUO}}_{\mathrm{ij}}}{\mathrm{PH}}$ (inferior/year)

In the formula, PH for put into operation day from boiler to safety evaluatio between day boiler in the calendar time of usefulness; NUO _IjFor the unplanned blowing out number of times that the j kind causes the fault mode of blowing out takes place in i parts of boiler;

The 5th step: blowing out MTTR mean repair time that calculates boiler component _Ij

Calculate i parts of boiler MTTR mean repair time that the j kind causes the fault mode of blowing out takes place _Ij

${\mathrm{MTTR}}_{\mathrm{ij}}=\frac{{\mathrm{UOH}}_{\mathrm{ij}}}{{\mathrm{NUO}}_{\mathrm{ij}}}---\left(h\right)$

In the formula, OL _iBe the calendar time that is accumulated at use of i parts of boiler, DL _iThe designed life that i the parts of boiler that provide for manufacturing enterprise adopt calendar time to represent;

The 6th step: the weight coefficient W that determines the boiler component failure effect _Ij

According to the experience of being engaged in evaluating boiler component probabilistic risk technical research work accumulation for many years, the weight coefficient W of the failure effect of j kind fault mode takes place in i parts of definition boiler _IjBe illustrated in table 2;

[table 2]

Fault type	The fault title	Failure effect	W ij
				I class fault	Special significant trouble	Cause blowing out, cause casualties and cause the great damage of boiler	10
II class fault	Significant trouble	Cause blowing out, cause casualties but do not cause the great damage of boiler	7
				III class fault	Important fault	Cause blowing out, cause the great damage of boiler but do not cause casualties	4
IV class fault	Than major break down	Cause blowing out, but do not cause great damage of boiler or casualties	1
				V class fault	Generic failure	Can not blowing out handle, but cause that boiler capacity reduces	0
VI class fault	Minor failure	Can not blowing out handle, do not cause that also boiler capacity reduces	0

The 7th step: the accumulation life consumption LE that calculates boiler component _i

Calculate the accumulation life consumption LE ' of i parts of boiler _i

${\mathrm{LE}}_i=\frac{{\mathrm{OL}}_i}{{\mathrm{DL}}_i}$

In the formula, OL _iBe the calendar time that is accumulated at use of i parts of boiler, DL _iThe designed life that i the parts of boiler that provide for manufacturing enterprise adopt calendar time to represent;

The 8th step: the risk ranking that calculates boiler component is counted RPN _Ij

Calculating i parts of boiler the risk ranking that the j kind causes the fault mode of blowing out takes place counts RPN _Ij

RPN _ij＝FP _ij×MTTR _ij×W _ij×LE _i

The 9th step: the risk class of determining boiler component

Risk ranking according to boiler component is counted RPN _IjSize, the probability risk of boiler component is divided into 5 grades, be illustrated in table 3;

[table 3]

The tenth step: the risk control measure of recommending boiler component

Risk ranking according to boiler component is counted RPN _IjCalculated value, recommend following risk control measure countermeasure:

(1) if RPN _Ij＜4, the Pyatyi risk is arranged, slight risk, acceptable risk, suggestion is by the plan interval and the scheduled overhaul content arrangement scheduled overhaul of " maintenance procedure " regulation;

(2) if 4≤RPN _Ij＜8, the level Four risk is arranged, ordinary risk, acceptable risk, suggestion is overhauled by " maintenance procedure " regulation, and is completely examined in next scheduled overhaul;

(3) if 8≤RPN _Ij＜24, tertiary risk is arranged, important risk, unacceptable risk, suggestion is the scheme of arrangement maintenance in this year, overhauls by " maintenance procedure ", and completely examines;

(4) if 24≤RPN _Ij＜40, the secondary risk is arranged, serious risk, unacceptable risk is advised the maintenance of scheme of arrangement within this month, overhauls by " maintenance procedure ", and completely examines;

(5) if RPN _Ij〉=40, primary risk is arranged, material risk, unacceptable risk, suggestion interior scheme of arrangement maintenance this week is overhauled by " maintenance procedure ", and is completely examined.

The present invention is according to the probability of malfunction of boiler component, mean repair time, failure effect weight coefficient and accumulation life consumption, and the risk ranking number of quantitative Analysis boiler component is estimated the risk of active boiler parts, instructs the risk control of boiler component.

Advantage of the present invention is to adopt risk ranking to count the probability risk of quantitative description boiler component, comes the scheme of arrangement maintenance according to the risk ranking number of boiler component, has both made the probability risk of boiler component be in slave mode; Reached the technique effect that reduces boiler component blowing out failure risk again.

Description of drawings

Fig. 1 is the process flow diagram of method for evaluating boiler component probabilistic risk of the present invention;

Fig. 2 is the computer software block diagram of this evaluating boiler component probabilistic risk;

Fig. 3 is boiler water wall pipe probabilistic risk assessment result's of the present invention synoptic diagram.

Embodiment

The invention will be further described below in conjunction with drawings and Examples.

Embodiment

Water-cooling wall pipe for certain model 300MW station boiler, adopt method for evaluating boiler component probabilistic risk process flow diagram shown in Figure 1 and program with the C language, be installed in the computer software of the evaluating boiler component probabilistic risk shown in Figure 2 in the power station production safety supervision section computing machine, the probabilistic risk assessment of this model boiler water wall pipe that calculates the results are shown in Fig. 3.

The first step: the water-cooling wall pipe of selecting this model boiler is the probabilistic risk assessment object;

Second step: put into operation at this model boiler the 15th year, carry out probabilistic risk assessment the 5th time;

The 3rd step: with reference to the reliability statistics method of existing boiler component, the damage position of this model boiler water wall pipe has: pipe (containing elbow), pipe and pipe weld bond, base and collection case weld bond, table (sampling) pipe, table (sampling) pipe (seat) weld bond; The damage mode of boiler water wall pipe has: overtemperature tube burst leaks, mother metal defective booster leaks, the booster leakage is decreased in the sizing that falls, the corrosion booster leaks, the drawing crack booster leaks, booster leaks, leakage; The blowing out of this model boiler water wall pipe causes that the fault mode of blowing out has: water-cooling wall pipe (containing elbow) booster leaks, water-cooling wall pipe (containing elbow) drawing crack booster leaks, water-cooling wall pipe (containing elbow) overtemperature tube burst leaks, water-cooling wall pipe (containing elbow) mother metal defective booster leaks, water-cooling wall pipe (containing elbow) corrosion booster leaks, water-cooling wall pipe (the containing elbow) sizing that falls is decreased booster and is leaked, water-cooling wall pipe and pipe weld bond booster leak, water-cooling wall pipe and base weld bond booster leak, the water-cooling wall base leaks with collection case weld bond, water-cooling wall table (sampling) pipe (seat) weld bond leaks, water-cooling wall table (sampling) pipe leaks;

The 4th step: the FP of this model boiler water wall pipe _IjResult of calculation be illustrated in table 4; [table 4]

Sequence number	The water-cooling wall pipe causes the fault mode of blowing out	FP i(inferior/year)
			1	Water-cooling wall pipe (containing elbow) booster leaks	0.3828
2	Water-cooling wall pipe (containing elbow) drawing crack booster leaks	0.1471
			3	Water-cooling wall pipe (containing elbow) overtemperature tube burst leaks	0.1390
4	Water-cooling wall pipe (containing elbow) mother metal defective booster leaks	0.0645
			5	Water-cooling wall pipe (containing elbow) corrosion booster leaks	0.0262
6	Water-cooling wall pipe (the containing elbow) sizing that falls is decreased booster and is leaked	0.0625
			7	Water-cooling wall pipe and pipe weld bond booster leak	0.1833
8	Water-cooling wall pipe and base weld bond booster leak	0.0141
			9	The water-cooling wall base leaks with collection case weld bond	0.0342
10	Water-cooling wall table (sampling) pipe (seat) weld bond leaks	0.0040
			11	Water-cooling wall table (sampling) pipe leaks	0.0040

The 5th step to the 6th step: MTTR mean repair time of this model Water Wall Tube in Station Boiler _IjWith failure effect weight coefficient W _IjBe illustrated in table 5; [table 5]

Sequence number	The water-cooling wall pipe causes the fault mode of blowing out	MTTR ij(h)	W ij
				1	Water-cooling wall pipe (containing elbow) booster leaks	102.34	1
2	Water-cooling wall pipe (containing elbow) drawing crack booster leaks	87.40	1
				3	Water-cooling wall pipe (containing elbow) overtemperature tube burst leaks	118.43	1
4	Water-cooling wall pipe (containing elbow) mother metal defective booster leaks	96.91	1
				5	Water-cooling wall pipe (containing elbow) corrosion booster leaks	111.27	1
6	Water-cooling wall pipe (the containing elbow) sizing that falls is decreased booster and is leaked	126.23	10
				7	Water-cooling wall pipe and pipe weld bond booster leak	101.89	1
8	Water-cooling wall pipe and base weld bond booster leak	96.62	1
				9	The water-cooling wall base leaks with collection case weld bond	72.83	7
10	Water-cooling wall table (sampling) pipe (seat) weld bond leaks	59.25	1
				11	Water-cooling wall table (sampling) pipe leaks	65.63	1

The 7th step: DL designed life of this model power station water-cooling wall pipe _i=8760 * 30=262800h, this model boiler put into operation 15 years, and the water-cooling wall pipe did not carry out large tracts of land to be changed, accumulative total calendar time OL _i=8760 * 15=131400h, the accumulation life consumption ${\mathrm{LE}}_i=\frac{131400}{262800}=0.5;$

The 8th step to the 9th step: the correspondence of this model Water Wall Tube in Station Boiler causes that the risk ranking of the fault mode that blowing out is different counts RPN _IjResult of calculation and risk class be illustrated in table 6;

[table 6]

Sequence number	Cause the fault mode of blowing out	RPN ij	Risk class	The risk type
					1	Water-cooling wall pipe (containing elbow) booster leaks	19.59	Tertiary risk	Unacceptable risk
2	Water-cooling wall pipe (containing elbow) drawing crack booster leaks	6.43	The level Four risk	Acceptable risk
					3	Water-cooling wall pipe (containing elbow) overtemperature tube burst leaks	8.23	Tertiary risk	Unacceptable risk
4	Water-cooling wall pipe (containing elbow) mother metal defective booster leaks	3.13	The Pyatyi risk	Acceptable risk
					5	Water-cooling wall pipe (containing elbow) corrosion booster leaks	1.46	The Pyatyi risk	Acceptable risk
6	Water-cooling wall pipe (the containing elbow) sizing that falls is decreased booster and is leaked	39.45	The secondary risk	Unacceptable risk
					7	Water-cooling wall pipe and pipe weld bond booster leak	9.34	Tertiary risk	Unacceptable risk
8	Water-cooling wall pipe and base weld bond booster leak	0.68	The Pyatyi risk	Acceptable risk
					9	The water-cooling wall base leaks with collection case weld bond	8.72	Tertiary risk	Unacceptable risk
10	Water-cooling wall table (sampling) pipe (seat) weld bond leaks	0.12	The Pyatyi risk	Acceptable risk
					11	Water-cooling wall table (sampling) pipe leaks	0.13	The Pyatyi risk	Acceptable risk

The tenth step: for 11 kinds of fault modes that cause blowing out of this model Water Wall Tube in Station Boiler, water-cooling wall pipe (the containing elbow) sizing that falls is decreased booster and is leaked and be the secondary risk; The leakage of water-cooling wall pipe (containing elbow) booster, the leakage of water-cooling wall pipe (containing elbow) overtemperature tube burst, water-cooling wall pipe and pipe weld bond booster leak, and the water-cooling wall base is tertiary risk with four kinds of blowing out fault modes that collect the leakage of case weld bond; The blowing out fault mode of all the other 6 kinds of water-cooling wall pipes is acceptable level Four risk and Pyatyi risk, the risk control measure of recommending is to arrange maintenance within this month, the water-cooling wall pipe of this model boiler is overhauled by " maintenance procedure ", and the secondary risk of this model boiler water wall pipe and tertiary risk are checked comprehensively and checked.

Adopt the evaluation method of the probability risk of boiler component provided by the invention, 11 kinds of risk ranking numbers that cause the blowing out fault mode of the water-cooling wall pipe correspondence of this model 300MW station boiler have been calculated, as shown in Figure 3, horizontal ordinate sequence number 1 is leaked for water-cooling wall pipe (containing elbow) booster among the figure, sequence number 2 is leaked for water-cooling wall pipe (containing elbow) drawing crack booster, sequence number 3 is leaked for water-cooling wall pipe (containing elbow) overtemperature tube burst, sequence number 4 is leaked for water-cooling wall pipe (containing elbow) mother metal defective booster, sequence number 5 is leaked for water-cooling wall pipe (containing elbow) corrosion booster, sequence number 6 is decreased booster and is leaked for water-cooling wall pipe (the containing elbow) sizing that falls, sequence number 7 is that water-cooling wall pipe and pipe weld bond booster leak, sequence number 8 is that water-cooling wall pipe and base weld bond booster leak, sequence number 9 is that the water-cooling wall base leaks with collection case weld bond, sequence number 10 is that water-cooling wall table (sampling) pipe (seat) weld bond leaks, and sequence number 11 is that water-cooling wall table (sampling) pipe leaks.Can determine corresponding risk class according to the risk ranking number; The risk class that causes the different faults pattern correspondence of blowing out according to the water-cooling wall pipe comes scheme of arrangement time between overhauls(TBO) and scheduled overhaul project, can make the probability risk of this model boiler water wall pipe be in slave mode, reach the technique effect that reduces this model boiler water wall pipe blowing out failure risk.

Claims (1)

1. a method for evaluating boiler component probabilistic risk is characterized in that, uses parts risk ranking number to come the computing method of quantitative description boiler component probabilistic risk and the evaluation method of boiler component probabilistic risk thereof, and its method is:

The first step: the evaluation object of selecting the boiler component probabilistic risk

Select some parts, certain several parts or several parts of boiler to carry out probabilistic risk assessment;

Second step: the evaluation cycle of boiler component probabilistic risk

The probabilistic risk assessment cycle of boiler component is taken as 2 years to 3 years, determines that according to the use year number of active boiler the evaluation cycle of boiler component probabilistic risk is illustrated in table 1;

[table 1]

Using a year number The probabilistic risk assessment cycle The 1st year to the 18th year 3 years The 19th year to the 30th year 2 years

The 3rd step: determine that boiler component causes the fault mode of blowing out

Use existing reliability statistics analytical technology can determine that boiler component causes the fault mode of blowing out;

The 4th step: the probability of malfunction FP that calculates boiler component _Ij

Program with the C language, operate in the computing machine, calculate i parts of boiler the probability of malfunction FP that the j kind causes the fault mode of blowing out takes place _Ij

${\mathrm{FP}}_{\mathrm{ij}}=\frac{8760\×{\mathrm{NUO}}_{\mathrm{ij}}}{\mathrm{PH}}$ (inferior/year)

In the formula, PH for put into operation day from boiler to safety evaluatio between day boiler in the calendar time of usefulness; NUO _IjFor the unplanned blowing out number of times that the j kind causes the fault mode of blowing out takes place in i parts of boiler;

The 5th step: blowing out MTTR mean repair time that calculates boiler component _Ij

Calculate i parts of boiler MTTR mean repair time that the j kind causes the fault mode of blowing out takes place _Ij

${\mathrm{MTTR}}_{\mathrm{ij}}=\frac{{\mathrm{UOH}}_{\mathrm{ij}}}{{\mathrm{NUO}}_{\mathrm{ij}}}---\left(h\right)$

In the formula, UOH _IjFor the unplanned furnace outage time that the j kind causes the blowing out fault mode takes place in i parts of boiler;

The 6th step: the weight coefficient W that determines the boiler component failure effect _Ij

According to the experience of being engaged in evaluating boiler component probabilistic risk technical research work accumulation for many years, the weight coefficient W of the failure effect of j kind fault mode takes place in i parts of definition boiler _IjBe illustrated in table 2;

[table 2]

Fault type The fault title Failure effect W _ij I class fault Special significant trouble Cause blowing out, cause casualties and cause the great damage of boiler 10 II class fault Significant trouble Cause blowing out, cause casualties but do not cause the great damage of boiler 7 III class fault Important fault Cause blowing out, cause the great damage of boiler but do not cause casualties 4 IV class fault Than major break down Cause blowing out, but do not cause great damage of boiler or casualties 1 V class fault Generic failure Can not blowing out handle, but cause that boiler capacity reduces 0 VI class fault Minor failure Can not blowing out handle, do not cause that also boiler capacity reduces 0

The 7th step: the accumulation life consumption LE that calculates boiler component _i

Calculate the accumulation life consumption LE of i parts of boiler _i

${\mathrm{LE}}_i=\frac{{\mathrm{OL}}_i}{{\mathrm{DL}}_i}$

In the formula, OL _iBe the calendar time that is accumulated at use of i parts of boiler, DL _iThe designed life that i the parts of boiler that provide for manufacturing enterprise adopt calendar time to represent;

The 8th step: the risk ranking that calculates boiler component is counted RPN _Ij

Calculating i parts of boiler the risk ranking that the j kind causes the fault mode of blowing out takes place counts RPN _Ij

RPN _ij＝FP _ij×MTTR _ij×W _ij×LE _i

The 9th step: the risk class of determining boiler component

Risk ranking according to boiler component is counted RPN _IjSize, the probability risk of boiler component is divided into 5 grades, be illustrated in table 3;

[table 3]

The tenth step: the risk control measure of recommending boiler component

Risk ranking according to boiler component is counted RPN _IjCalculated value, recommend following risk control measure countermeasure:

(1) if RPN _Ij＜4, the Pyatyi risk is arranged, slight risk, acceptable risk, suggestion is by the plan interval and the scheduled overhaul content arrangement scheduled overhaul of " maintenance procedure " regulation;

(2) if 4≤RPN _Ij＜8, the level Four risk is arranged, ordinary risk, acceptable risk, suggestion is overhauled by " maintenance procedure " regulation, and is completely examined in next scheduled overhaul;

(3) if 8≤RPN _Ij＜24, tertiary risk is arranged, important risk, unacceptable risk, suggestion is the scheme of arrangement maintenance in this year, overhauls by " maintenance procedure ", and completely examines;

(4) if 24≤RPN _Ij＜40, the secondary risk is arranged, serious risk, unacceptable risk is advised the maintenance of scheme of arrangement within this month, overhauls by " maintenance procedure ", and completely examines;

(5) if RPN _Ij〉=40, primary risk is arranged, material risk, unacceptable risk, suggestion interior scheme of arrangement maintenance this week is overhauled by " maintenance procedure ", and is completely examined.

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