Dynamic Safety Management on the Key Equipment of Coal Gasification Based on Dbt-Dbn Method

Table 4

Basic event description and related data.

Symbol	Description	Failure model	Experts’ judgement					Fps	Fpr (λ)	µ
			E1	E2	E3	E4	E5
X1	Burner wear	Facilities failure	RH	RL	H	RH	H	0.674325	1.57E-02	0.25
X2	Center-oxygen flow valve failure	Facilities failure	RL	VL	M	M	M	0.410953	2.54E-03	0.125
X3	Blockage of center-oxygen check valve	Facilities failure	RL	VL	L	RL	RL	0.276973	6.79E-04	0.25
X4	Blockage of CWS pipeline at gasifier head	Facilities failure	M	VL	VL	RL	L	0.251819	4.92E-04	0.25
X5	Blockage of burner	Facilities failure	M	L	L	RL	L	0.297298	8.61E-04	0.25
X6	Drain valve of CWS pipeline opened by error	Operational error	L	L	L	M	L	0.264865	5.84E-04	—
X7	CWS circulating valve opened by error	Operational error	L	L	VL	M	VL	0.213133	2.78E-04	—
X8	Leakage of CWS circulating valve	Facilities failure	L	L	L	RH	L	0.297298	8.61E-04	0.125
X9	CWS block valve closed by error	Operational error	L	RL	VL	M	VL	0.233172	3.79E-04	—
X10	Blockage of CWS pipeline	Facilities failure	RH	L	VL	RL	RL	0.328724	1.20E-03	0.25
X11	Leakage of CWS pipeline	Facilities failure	RL	VL	VL	M	L	0.251819	4.92E-04	2
X12	Agitator failure in the mill discharge tank	Facilities failure	L	RL	VL	RL	L	0.223507	3.27E-04	0.25
X13	Blockage of low-pressure CWS pump inlet	Facilities failure	M	L	VL	M	RL	0.329061	1.21E-03	0.25
X14	Coal mill failure	Facilities failure	L	M	VL	RH	L	0.308765	9.77E-04	0.5
X15	Manhole leaks in the CWS tank	Facilities failure	RL	VL	VL	RL	L	0.219144	3.06E-04	0.5
X16	Low-pressure CWS primary pump failure	Facilities failure	RL	L	L	L	L	0.232433	3.75E-04	0.33
X17	Low-pressure CWS standby pump failure	Facilities failure	L	L	VL	VL	VL	0.121677	3.57E-05	0.33
X18	High-pressure CWS primary pump failure	Facilities failure	RL	VL	RL	RL	RL	0.313381	1.03E-03	0.33
X19	High-pressure CWS standby pump failure	Facilities failure	L	VL	VL	VL	VL	0.104881	1.98E-05	0.33
X20	Blockage of high-pressure CWS pump inlet	Facilities failure	M	L	L	M	RL	0.358108	1.60E-03	2
X21	Agitator failure in the CWS tank	Facilities failure	L	VL	L	RL	L	0.216358	2.93E-04	0.25
X22	The opening of oxygen flow valve is too large	Operational error	L	M	RL	RL	RL	0.33784	1.32E-03	—
X23	The pressure of oxygen buffer tank outlet is too high	Operational error	L	RL	VL	M	VL	0.233172	3.79E-04	—
X24	Safety valve of carbon washing tower opened by error	Operational error	L	L	VL	RL	L	0.203358	2.36E-04	—
X25	Syngas purge valve opened by error	Operational error	L	RL	VL	RL	VL	0.200452	2.24E-04	—
X26	Leakage of pipeline connected with gasifier	Facilities failure	M	M	VL	M	RL	0.369603	1.78E-03	0.33
X27	Leakage of flange connected with gasifier	Facilities failure	RL	RH	RL	RH	M	0.483786	4.45E-03	0.33
X28	Leakage of lock hopper	Facilities failure	M	RH	VL	M	L	0.361554	1.65E-03	0.33
X29	Leakage of slurry flush valve	Facilities failure	RL	VL	L	RH	L	0.313537	1.03E-03	0.125
X30	Slurry flush valve opened by error	Operational error	L	RL	L	M	L	0.285136	7.48E-04	—
X31	Blockage of coal bunker outlet	Facilities failure	RL	RL	VL	H	M	0.409993	2.52E-03	0.25
X32	Blockage of coal mill screen	Facilities failure	RH	RH	VL	H	RH	0.543641	6.75E-03	0.25
X33	Slurry flush valve failed to close	Operational error	L	L	VL	L	VL	0.148269	7.57E-05	—
X34	The opening of mill feed water flow valve is too large	Operational error	L	M	L	RL	L	0.272975	6.46E-04	—
S1	Overheating detection alarm failure	Multiple failure	M	RL	RL	RL	M	0.321622	1.12E-03	—
S2	Manual cooling operation failure	Multiple failure	M	RL	M	RH	RL	0.366216	1.73E-03	—
S3	ESDa failure	Multiple failure	RL	RL	M	RL	RL	0.297298	8.61E-04	—
S4	ESDm failure	Multiple failure	L	M	RL	RL	RL	0.20259	2.33E-04	—