TFC KAOHSIUNG FACTORY 30 KMT AMMONIA STORAGE TANK DECOMMISSION REPORT. By: Jackson Yang (TFC R&D Department) 01 Oct 2016

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1 TFC KAOHSIUNG FACTORY 30 KMT AMMONIA STORAGE TANK DECOMMISSION REPORT By: Jackson Yang (TFC R&D Department) 01 Oct

2 CONTENT 1. Introduction 2. Technical Information of TFC 30,000 MT Ammonia Storage Tank (T-101) 3. Planning of T-101 Decommission Project 4. Implementation of T-101 Decommission Project A. Level Reduction B. Evaporation & Condensation C. Nitrogen & Air Purge D. External & Internal Shell Opening E. Tank Internal Observation & Cleaning 5. Review & Recommendation 6. Summary 2

3 1. Introduction

4 Background TFC Kaohsiung Factory 30,000 MT Ammonia Storage tank T-101 was installed nearby Kaohsiung port in For 27 years ( ), this tank was well maintained and successfully operated without incurring any incident related to safety or environmental issues. According to the new business development plan, TFC has decided to convert the land of Kaohsiung Factory to business district. Therefore, T-101 ammonia tank has to be decommissioned and demolished. T-101 ammonia tank is located at the center of Kaohsiung City with around 2.8 million populations. In case of mishandling, it will wreak havoc to the community and the public. There is no domestic engineering contractor has the experience of huge ammonia tank decommissioning, nor guarantee of safe handling. After thorough consideration, TFC top management decided to form an in-house project team to handle it.

5 Map of TFC Kaohsiung Factory & T-101 Kaohsiung Factory T-101 5

6 Surrounding of Ammonia Tank T-101 North-West North-East T-101 South-East East 6

7 2. Technical information of Ammonia Tank T-101

8 Description of Ammonia Storage Tank T-101 T-101 is a flat bed, double wall & double roof anhydrous liquid ammonia storage tank. The internal wall is constructed with low temperature resistant steel plate and outer wall is constructed by steel covered with reinforced concrete wall. Inside of external wall has 6m/m layer of low temperature resistant steel and a layer of insulation cotton. The internal tank dimension is 48 meter diameter and 38 meter height with 60,000 cubic meter volume. The design storage capacity is 30,000 MT anhydrous liquid ammonia. All the tank nozzles and transfer pump connections are located at the tank roof, there is no any nozzle connection at the side or bottom of the tank. The tank was designed and constructed in 1987 by Mitsubishi Heavy Industries & Chiyoda Tank Engineering Corporation, Japan.

9 Ammonia Tank T-101 General Assembly 9

10 T-101 Equipment Name Plate (Design Specification)

11 3. Planning of T-101 Decommission Project

12 Outline of Ammonia Tank T-101 Decommission Plan Level Reduction Evaporation & Condensation Nitrogen Purge Air Purge Internal Cleaning 12

13 Description of Ammonia Tank T-101 Decommission Plan 1. When Kaohsiung factory stopped production as order, ammonia transfer pumps should continue running to decrease the level in T-101 until the pump tripped by low level interlock. Bypass the level interlock switch and raise pump high vibration setting then restart the transfer pump until pump cavitation to minimize the tank level. 2. The remaining liquid ammonia in tank will be heated & removed by Boil-Off Gas (BOG) compressor then send out to road tanker for sale. 3. When all liquid ammonia in the tank gone, nitrogen gas will be injected to purge the remaining ammonia gas in tank. The purge gas will vent to flare or passing through water column to absorb the ammonia gas. 4. As soon as the ammonia content in tank is less than 10% (ammonia gas explosive limit: 15%~28%), stop nitrogen purge and start air purge. 5. When ammonia content in tank is less than 50 ppm and oxygen content is the same as atmosphere, tank entry can be permitted to do cleaning and inspection. 13

14 Tank internal and wall cleaning TFC Kaohsiung Factory Flare

15 CHALLENGE MHI ammonia tank is designed with ammonia in/out nozzles located at tank top side. The steel tank wall is protected with full covered concrete structure. There is no side or bottom nozzle to be utilized during decommissioning. After ammonia transfer pumps getting low suction, there is still 1,100 MT of liquid ammonia remaining in the tank. This quantity of ammonia can be recovered only by evaporation and condensation. The ammonia storage tank is located at the center of Kaohsiung City with population of 2.8 million. The distance to the nearby crowded Dream shopping mall is only few hundred meters only. In case of ammonia gas leakage, it will play havoc to community and the public. The engineering contractor estimated to cost US$ 2 million for decommissioning the ammonia tank without guarantee. 15

16 4. Implementation of T-101 Decommission Project

17 4A. LEVEL REDUCTION

18 Level Reduction Operation Kaohsiung factory stopped production in the end of Nov 2014 as instruction, ammonia transfer pumps continued running to decrease the level in T-101 until the pump tripped by low level interlock. The remaining ammonia in tank was 1,936 MT. On 22 Dec 2014, bypassed the level interlock switch and raised pump high vibration setting then restarted the transfer pump until pump stopped by cavitation. During 42 hours of continued pumping, 820 MT ammonia had been pumped out and the remaining ammonia in tank was 1,106 MT. All 3 units of transfer pumps had been dismantled and kept them as spare for future use. 18

19 T-101 Ammonia Transfer Pumps The Operation Platform of 3 Ammonia Transfer Pumps

20 Location of Thermometers inside Ammonia Tank T-101 # of Thermometer Location (M) # Thermometer Location (M) T

21 Temperature ( o C) 2015/3/ /3/ /3/ /3/ /3/ /4/1 2015/4/2 2015/4/3 2015/4/4 2015/4/5 2015/4/6 2015/4/7 2015/4/8 2015/4/9 2015/4/ /4/ /4/ /4/ /4/ /4/ /4/ /4/ /4/ /4/ /4/ /4/ /4/ /4/ /4/ /4/ /4/ /4/ /4/ /4/ /4/30 Temperature Profile inside T-101 during Level Reduction stage (10.00) #6 #7 #8 #9 #10 Ambient T (20.00) (30.00) (40.00) 21

22 4B. EVAPORATING & CONDENSING

23 Description of Evaporating & Condensing Operation 1. The project team had designed to evaporate the remaining 1,106 MT liquid ammonia in tank by the following schemes: 1. Temperature difference between T-101 and atmosphere 2. T-101 foundation heater 3. Recycle hot ammonia gas from unloading sphere tank 4. Air heating at T-101 annular space 2. Modified the existing Boil-Off Gas (BOG) compressor discharge lines so that the recovered liquid ammonia will flow to unloading sphere tank instead of returning to T-101. (Refer to T-101 Evaporation and Condensation PFD) 3. Stopped the existing N 2 sealing at T-101 annular space and replaced N 2 by injecting heated compressed air to annular space. It can both save the N 2 cost and accelerate the ammonia evaporation rate. (Refer to T-101 Annular space air heating system) 23

24 Actual Progress of Evaporating & Condensing Stage The Evaporating & Condensing Stage started on 20 Mar 2015 and ended on 13 Dec 2015(#6 temp. near 0 ), average daily ammonia recovery rate is 4.57 MT;total recovery quantity is 1,199.2 MT Comparison of Design & Actual Rate: Evaporation & Condensation Schemes Design Rate Actual Rate Remarks 1. Natural Evaporation (MT/D) Heated by ATM 2. Foundation heater (MT/D) Foundation heater set at Recycle hot ammonia gas (MT/D) 4. Air heating at annular space (MT/D) Total (MT/D) ~ ~1 Recycle gas is ambient temp ~1.5 Annular space air temp. is 20~40 24

25 Tem. ( o C) T-101 Temperature Profile until end of Evaporating & Condensing stage (10.00) #6 #7 #8 #9 #10 Ambient T (20.00) (30.00) (40.00) 25

26 4C. NITROGEN & AIR PURGE

27 Description of Nitrogen Purge Operation 1. When all ammonia level in tank has gone, it can be confirmed by observing tank bottom temperature increased from -33. Injection of nitrogen gas to start tank purging can be initiated. 2. The venting purged gas comprises of NH 3 & N 2 was initially planned to burn and vent through the existing flare at Kaohsiung factory. However, the existing flare does not have auxiliary gas combustion facility. The pilot flame will be extinguished by the nitrogen rich vent gas and the surrounding will be polluted by ammonia leakage. 3. To ensure no ammonia leakage to surrounding, the project team designed a vent gas stripping system: The vent gas will be boosted by compressor or vacuum pump then passing through water column to absorb ammonia gas, finally the remaining nitrogen gas can be vented to atmosphere. (Refer to the vent gas stripping system PFD and process simulation data) 27

28 Nitrogen Purge Actual Progress Thanks to S. Advisor Mr. Chu who arranged to borrow the vacuum pump from China Petroleum Company, it saved millions of cost for purchasing the new compressor as estimated. The installation of vacuum pump and the associated NH 3 gas stripping system had been completed in 20 days. On 30 Dec 2015, started the nitrogen purge and the operation of vent gas stripping system. For accelerating the N 2 purge rate, a rented high capacity vacuum compressor was arranged on Feb It has three times of vacuum pump capacity, up to 1,000 M 3 /H. The vacuum compressor and the related pipelines had been installed and started on 10 Mar The N 2 purge rated to T-101 was increased. On 6~8 Apr 2016, T-101 ammonia gas content was less than 10% consecutively, meeting the end point of N 2 purge criteria. N 2 purge stage started from 30 Dec 2015 to 10 Apr 2016, average N 2 consumption was 3.04 MT/D and total N 2 consumption was MT. Total ammonia recovery from NH 3 gas stripping system was MT. 28

29 Recovered NH 3 Quantity from Purge Gas Stripping System Accumulation (MT) Recovered NH 3 Accumulation (MT) /12/ /1/ /1/ /2/ /3/ /3/ /4/20 29

30 NH3 Concentration (Wt%) Ammonia Gas Content in T % T-101: NH3 Concentration (Wt%) % 80.00% 60.00% 40.00% 20.00% 0.00% 2015/12/2 2015/12/ /1/ /1/ /2/ /3/ /3/ /4/ /5/ /5/30 T-101 Act. NH3 conc. (by recovered NH3) Wt% T-101 Avg. NH3 conc. (by NH3 sensor) Wt% Moving Avg. (Avg. NH3 conc. (by NH3 sensor, wt%) 30

31 N 2 Consumption (MT) N 2 Consumption during N 2 Purge N 2 Consumption during N 2 Purge (MT) /12/ /1/6 2016/1/ /2/5 2016/2/ /3/6 2016/3/ /4/5 2016/4/20 31

32 Air Purge Actual Progress On 11 Apr 2016, closed N 2 injection to T-101 and started air purge. On 13 Apr 2016, open T-101 inner tank southern manhole, found it was sealed by steel plate from inside. Cut open the sealed steel plate by water jet cutting. On 14 Apr 2016, removed one unit of RV and vacuum breaker each at T-101 roof to accelerate the air purge rate. On 15 Apr 2016, open T-101 inner tank northern manhole and cut open the sealed steel plate by water jet cutting. On 25 Apr 2016, Stopped vacuum compressor and NH 3 stripping system, open 2 numbers of 8 nozzle at roof to sweeten T-101. On 28 Apr 2016, Completed opening a 3.2M*3.0M vehicle entrance hole at T-101 southern side to allow entrance of working personnel. On 3 May 2016, O 2 content was 20.9% and NH 3 content was 3 PPM inside T-101, air purge stage has completed. 32

33 O 2 content (WT%) Oxygen Content in T-101 during Air Purge T-101 Oxygen Content During Air Purge (Wt%) /4/ /4/ /4/ /4/ /4/ /5/5 2016/5/10 33

34 T-101 Temperature Profile Until Air Purge Temp. ( o C) (10.00) #6 #7 #8 #9 #10 Ambient T (20.00) (30.00) (40.00) 34

35 4D. OUTER WALL & INNER MAN-HOLE OPENING

36 T-101 External & Inner Wall Opening Outer wall opening: 1. On 22 Feb 2016, Cut and open the first hole of T-101 outer wall at southern side, the inner tank manhole is visible to us. 2. On 28 Feb 2016, Cut and open the second hole of T-101 outer wall at northern side. 3. On 22 Mar 2016, Hot tapping a 2 observation nozzle with valve at inner tank, it can serve to monitor the NH3 content at the bottom of inner tank. Inner manhole opening: 1. On 13 Apr 2016, Open the inner tank manhole at southern side, found the manhole opening was welded with steel plate. Cut the welded plate to open the manhole. 2. On 15 Apr 2016, Open the second inner tank manhole at northern side and cut the welded plate to open the manhole. 3. On 28 Apr 2016, Cut a 3.2M*3.0M working entrance at tank southern side. 4. On 3 May 2016, T-101 inner tank oxygen was 20.9% and ammonia content was 3 PPM. Tank entry is safe and permitted. 36

37 The first hole of T-101 outer shell (southern side) has completed on 22 Feb The manhole at T-101 inner wall (southern side) was visible.

38 Hot tapping for the inner wall of T-101 was in progress on 22 Mar A 3.2M*3.0M hole for vehicle & personnel entrance at tank southern side.

39 4E. TANK ENTRY & OBSERVATION

40 T-101 Tank Entry and Observation Finding 1. On 14 Apr 2016, cut the welded plate to open the southern manhole. T-101 internal sight is visible to us for the first time after 27 years of service. The initial observation found the tank bottom has a thin layer of dry white powder, there is no oil or mud as expected before. 2. On 18 Apr 2016, collected the tank bottom white powder to do combustion and explosion test, the test result is negative. The source of this powder is speculated to be coming from catalyst beds during ammonia manufacturing process. 3. On 20 Apr 2016, take the video shot of T-101 bottom sight to keep the record for future reference. 4. On 3 May 2016, T-101 inner tank oxygen was 20.9% and ammonia content was 3 PPM. Tank entry is safe and permitted without using the breathing apparatus or other protection gear. 40

41 Ammonia Tank T-101 Internal View 1 Liquid NH 3 transfer pumps T-101 level indicatin float disk

42 Ammonia Tank T-101 Internal View 5 Internal ladder Liquid NH 3 transfer pumps

43 Ammonia Tank T-101 Internal View 5 Tank bottom with thin layer of white powder

44 Ammonia Tank T-101 Internal View 6 Tank bottom view

45 Ammonia Tank T-101 Annular space View 45

46 Internal Cleaning 1. Date: Technicians got entry permit to start T-101 internal cleaning on 26 May The internal cleaning & waste disposal were completed on 9 Jun Contractor: Local contractor ( 沅水企業有限公司 ) 3. Cost: Internal cleaning & waste collecting (about 0.3 million NTD). 4. Description: Collected the bottom white powder by small bags for disposal (30 bags, total about 1 MT). The tank wall was washed by hydro jetting from bottom up to 6 meters height. The generated waste water was directed to aqua NH3 tank and transferred to TFC Taichung Factory for treatment & recovery. 46

47 Tank bottom white powder collecting & cleaning

48 Tank wall cleaning by hydro jetting

49 5. REVIEW & RECOMMENDATION

50 1. Comparison of Dry & Wet Decommission Processes Brief description of dry & wet Processes: Dry Process: Decommissioning will proceed step by step following level reduction, evaporation & condensation, temperature raising, nitrogen & air purge without water addition in the process. This was adopted by the project team, it took longer time to complete but eliminated the problem of waste water handling. Wet Process: To accelerate the decommissioning process, added water to the tank after tank level empty then completed by nitrogen & air purge. The project team had studied and planned to implement wet process (Refer to 2. T-101Wet Decommission Plan). It was abandoned due to waste water handling problem and safe operation concern. However, wet process can be considered as an alternative way in case the requirement of fast decommissioning is necessary in the future. 50

51 2. Outline of T-101 Wet Decommission Plan Empty Tank & Raise Temp. Add Water to Tank Build Water Level in Tank Tank Wall Hot- Tapping Aqua NH 3 Circulation 51

52 3. Review & Recommendation on T- 101 Decommission Operations 3.1 Level Reduction 3.2 Evaporation & Condensation 3.3 N 2 Purge 52

53 6. SUMMARY

54 Project Conclusion The decommission project of ammonia storage tank T-101 was designed and executed by TFC in-house engineering team in The project initiated on 22 Dec 2014 by starting level reduction until 9 Jun 2016 internal cleaning completed. The project total duration was 415 days. During implementation, there is no incident incurring related to safety or environment issues. TFC Taichung Factory has two 20,000 MT ammonia storage tanks with the same design as T-101. The decommission experience of T-101 can provide valuable reference to Taichung Factory in future. The actual project cost is less than 20 million NTD that is much less than the estimated 40 million NTD above by out source contractor. 54

55 End of Presentation & Thank You! 55

56 Revised T-101 Evaporation and Condensation PFD PIC 101 IA SCR Air*2 IA-02 Air vent 3 -Air LT-01 電熱 ( 新設 ) Air 迴流至槽頂 24 MH 2 -Air 電熱 ( 原有 ) XV AG 迴流至槽底 12 -AG T-101 K st stage LT AG CW 3 -AG LIC 305 From K-201A/B 6 1 V AG ( 新設 ) 2 nd stage AG LT-304 LIC 304 LCV-307 ( 新設 ) AG 6 -AG 2 -LA 7 LCV-305 PV-101 V-105 ( 截斷盲封 ) LV AG PY-101 LCV-304 ( 改 HCV) 2 -LA NA-16/17 8 圖示說明 NAB- 16/17 新設液氨回收管線新設氣氨迴流至槽底管線新設空氣加熱管線原有電熱器 56

57 T-101 Annular Space Air Heating System Vent to ATM Air Air Compressor Filter Dryer Electric heater NH 3 Tank T

58 Evaporating Rate (MT/D) Daily Actual & Average Ammonia Recovery Rate 14 T-101 Daily Evaporating Rate Actual vs. Average Actual Average /3/ /4/ /5/ /6/ /7/ /8/ /9/ /10/ /11/20 58

59 T-101 Purge Gas Stripping System PFD 59

60 Purge Gas Stripping System Process Simulation 60

61 Gas Inlet Gas Outlet Vacuum Pump

62 Purge Gas Stripping System DCS Indication

63 3.1 Recommendation of Level Reduction Operation Recommendation to improve the level reduction operation: 1. Remove low level interlock and pump high vibration switches of NH 3 transfer pump then start level Reduction operation. 2. On observing pump discharge pressure indication hunting, stop the transfer pump by manual. 3. By this way, more quantity of NH 3 can be pumped out due to siphon. It can minimize the remaining NH 3 in T

64 3.2 Recommendation of Evaporating & Condensing Operation Recommendation to improve evaporating & condensing operation: 1. To install electric coil heater around ammonia gas recycle pipeline and control the recycle gas temperature in less than 70 o C, it can accelerate the liquid ammonia evaporating rate in T To increase annular space air heater temperature up to 70 o C from beginning to speed up the liquid ammonia evaporating rate in T Applying above measures can increase the ammonia evaporating rate to above 10 MT/D and speed up evaporating & condensing operation. 64

65 3.3 Recommendation of N 2 Purge Operation Recommendation to improve N 2 purge operation: 1. The existing flare on site has only pilot burner without equipping auxiliary burning facility. The purge gas venting to flare will extinguish the pilot flame causing NH 3 gas escape to atmosphere and pollute the environment. 2. The solution is to install a temporary auxiliary fuel gas line for combustion supplement to the exhaust of flare before initiation of N 2 purge. This auxiliary fuel gas flow should be adjustable according to the flow rate of vent gas. By this modification, the purge gas can be diverted to flare to burn the NH 3 content then vent to atmosphere directly. It can save the cost of installing both vacuum compressor & NH 3 stripping system and speed up N 2 purge stage in the consequence. 65

a. CFCs. b. HCFCs. c. Pressurized nitrogen. d. Compressed dry air. 17. The state of the refrigerant leaving the condenser of a refrigeration system

a. CFCs. b. HCFCs. c. Pressurized nitrogen. d. Compressed dry air. 17. The state of the refrigerant leaving the condenser of a refrigeration system Core 1. Ozone in the stratosphere above the earth consists of: a. Molecules containing 3 oxygen atoms. b. Molecules of 2 oxygen atoms. c. Radioactive particles. d. Pollutants that have risen from ground