大罐吹掃、干燥、預(yù)冷方案.doc

靖邊西藍天然氣綜合利用項目10000 M3LNG儲罐安裝工程靖邊西藍天然氣綜合利用項目10000M3LNG儲罐吹掃、預(yù)冷方案 編制： 安全： 審核： 審批： 張家港中集圣達因低溫裝備有限公司 2010年9月3日目 錄1、SCOPE范圍2、CRITERIA OF PURGING AND DRYING干燥和吹掃標準3、PRELIMINARY CHECKS AND SET-UP初步的檢查和組織安排4、QUALITY OF NITROGEN GAS氮氣質(zhì)量5、NITROGEN PURGE AND DRY OUT氮氣吹掃和干燥 5.1、Purge and dry out inner tank Zone A (Step 1) 內(nèi)罐區(qū)域A吹掃和干燥（步驟1） 5.2、Purge and dry out zone B (step 2) 區(qū)域B吹掃和干燥（步驟2） 5.3、Purge and dry out bottom (step 3) 底部吹掃和干燥（步驟3） 5.4、Purge and dry out of nozzles and zone B (step 4) 管道與區(qū)域B吹掃與干燥（步驟4）6、PRODUCT GAS PURGE產(chǎn)品氣體吹掃 6.1、Initial conditions初始條件 6.2、Product Gas purge Zone A (step 5) 產(chǎn)品氣體吹掃區(qū)域A（步驟5） 6.3、Product gas Purge, Zone B (step 6) 產(chǎn)品氣體吹掃區(qū)域B（步驟6） 6.4、Product gas purge of nozzles (Step 7) 產(chǎn)品氣體吹掃管道（步驟7）7、COOL-DOWN冷卻 7.1、Initial conditions (step 8) 初始條件（步驟8） 7.2、Cool-down process (step 9) 冷卻過程（步驟9）8、Appendix A Tools and Instruments附錄A-工具和儀表1 SCOPE范圍This specification covers the procedure for purging, dry out and cool down of one 10000 m3 capacity, single integrity, refrigerated storage tank, storing LNG at -163C. 說明文件描述容積為一萬方、結(jié)構(gòu)完整、低溫儲罐、儲存LNG溫度為-163C 的儲罐，內(nèi)容為吹掃、干燥以及冷卻程序Note: Product stated in this procedure refers to LNG AT -163C. Product gas stated in this procedure refers to warm (ambient temperature) LNG vapour. 注意：所規(guī)定的“產(chǎn)品”指-163C 的LNG，所規(guī)定的“產(chǎn)品氣體”指環(huán)境溫度下的LNG蒸汽。2 CRITERIA OF PURGING AND DRYING吹掃和干燥標準Criteria of Oxygen purging and drying using Nitrogen shall be as follows: 用氮氣吹掃和干燥氧氣的標準應(yīng)是列舉如下：ZONE區(qū)域O2 CONCENTRATION(VOL %)氧氣濃度DEW POINT露點(AT ATMOSPHERIC PRESSURE) 在大氣壓力下A: INNER TANK AND DOME SPACE內(nèi)罐和頂部空間 8%BELOW 20 C低于-20 CB: ANNULAR SPACE夾層 8%BELOW 20 C * NOTE低于-20 C*注釋Criteria of Nitrogen purging using Product gas shall be as follows: 用產(chǎn)品氣體吹掃和干燥氮氣的標準應(yīng)是列舉如下：ZONE 區(qū)域N2 CONCENTRATION(VOL %)氮氣濃度DEW POINT露點(AT ATMOSPHERIC PRESSURE) 在大氣壓力下A: INNER TANK AND DOME SPACE 內(nèi)罐和頂部空間 8%BELOW 20 C低于-20 CB: ANNULAR SPACE 夾層98%Dew point露點 -60CFlow rate流量300-600 nmchnmch = normalised metre 3 per hour5 NITROGEN PURGE AND DRY OUT氮氣吹掃和干燥5.1 Purge and dry out inner tank Zone A (Step 1) 內(nèi)罐區(qū)域A吹掃和干燥（步驟1）a) Monitor the tank pressure during purge and dry out. 在吹掃和干燥過程中監(jiān)測儲罐壓力b) Ensure Nitrogen bottom purge valve N4, annulus purge valve N16 and Bottom purge valves N23A & B are closed during purge of inner tank. 確保底部進氣閥N4、夾層排氣閥N16、底部排氣閥N23A&B在吹掃內(nèi)罐的過程中是關(guān)閉的。c) Open valve on purge inlet nozzle (N 15) and introduce Nitrogen gas into the inner tank. 打開N15管口上的閥門，吹掃氮氣通過此管口進入內(nèi)罐。d) When the inner tank pressure reaches 400mm H2O open the valve on purge vent nozzle (N17) and discharge the purge gas to atmosphere. 當內(nèi)罐壓力達到400mmH2O時，打開吹掃排放管口N17上的閥門，吹掃氣體從此管口排放出去。e) Ensure that the Nitrogen gas is supplied at a rate between 300 to 600 Nm3/hr. Start purge at the lower rate and gradually increase after 4 hours. 確保氮氣在300到600 Nm3/hr之間，在較低比率時開始吹掃，在4小時后逐漸上升。f) Monitor the O2 concentration and the dew point of the vented Nitrogen gas at N 17. When the O2 concentration and dew point of the vented Nitrogen gas at N1 7 is approaching the required levels as defined in section 2 above then proceed to the next section(step2). 監(jiān)測N17排放出氮氣中的氧氣濃度和露點。當氧氣濃度和露點接近在第2部分定義的要求時，然后進入下一步驟（步驟2）。5.2 Purge and dry out zone B (step 2) 區(qū)域B吹掃和干燥（步驟2）a) When the Oxygen concentration at N1 7 is less than 8% during purge of the inner tank and roof space as described above open the valve N16 to commence purging of zone B. 當在N17位置在內(nèi)罐和頂部空間吹掃過程中如上敘述氧氣濃度低于8%時，打開N16閥門開始吹掃區(qū)域BWARNING, ENSURE ALL PRECAUTIONS ARE IN PLACE TO ENSURE ALLPERSONNEL ARE PROTECTED FROM SUFFOCATION FROM NITROGEN GAS DURING THE PURGE OPERATION. 警告，確保所有預(yù)防措施到位以保證所有人員受到防護，避免在吹掃過程中因氮氣導(dǎo)致窒息。b) Monitor the O2 concentration and the dew point of the vented Nitrogen gas at N 17. 監(jiān)視N17排放出氮氣中的氧氣濃度和露點c) When the vented gas and dew point of the vented Nitrogen gas at N1 7 are below the required levels as defined in section 2 above reduce the supply rate of Nitrogen and then close nozzle N1 7. The supply rate of the Nitrogen should be adjusted to avoid over pressurising the outer tank. It is important to purge the annular space slowly to avoid the purge gas tunnelling through the resilient blanket alone. 當排放氣體和N17位置排放氮氣的露點低于在第2部分定義的要求時，降低氮氣的供氣量然后關(guān)閉管口N17。氮氣供氣量應(yīng)調(diào)節(jié)以避免對外罐施加過多的壓力。緩慢置換夾層是很重要的，要避免產(chǎn)生隧道效應(yīng)（吹掃氣體只單獨穿過彈性毯）d) Proceed to the next section (step 3). 進入下一步驟（步驟3）5.3 Purge and dry out bottom (step 3) 底部吹掃和干燥（步驟3）e) When the Oxygen concentration at N16 is less than 10% during purge of the annular space as described above open valves N4, N23A & B to commence purging of the bottom insulation. 當吹掃夾層過程中如上所述N16位置處氧氣濃度低于10%時，打開N4、N23A&B閥門開始吹掃底部絕熱層。WARNING, ENSURE ALL PRECAUTIONS ARE IN PLACE TO ENSURE ALLPERSONNEL ARE PROTECTED FROM SUFFOCATION FROM NITROGEN GAS DURING THE PURGE OPERATION. 警告，確保所有預(yù)防措施到位以保證所有人員受到防護，避免在吹掃過程中因氮氣導(dǎo)致窒息。f) Monitor the O2 concentration and the dew point of the vented Nitrogen gas at N23A & B. 監(jiān)測N23A&B排放氮氣中氧氣濃度和露點g) When the concentration and dew point of the vented Nitrogen gas at N23A & B is below the required levels as defined in section 2 above then close nozzles N4, N23A & B and reduce the supply rate of Nitrogen. The supply rate of the Nitrogen should be adjusted to avoid over pressurising the outer tank. 當N23A&B排放氮氣的濃度和露點低于如上所述第二部分中定義的要求時，關(guān)閉管口N4、N23A&B，以及降低氮氣供氣量。氮氣供氣量應(yīng)被調(diào)節(jié)以避免對外罐施加過多的壓力h) Proceed to the next section (step 4). 進入下一步驟（步驟4）5.4 Purge and dry out of nozzles and zone B (step 4) 管嘴與區(qū)域B吹掃與干燥（步驟4）a) During the purging of zone B purge out all nozzles and roof top piping. Open each valve on all nozzles, piping and appurtenances to purge any entrapped air. 在吹掃區(qū)域B時，吹掃所有管口和頂部管道，打開所有管口、管道、附件的閥門進行吹掃任何位置夾帶的空氣。b) Monitor the O2 concentration and the dew point of the vented Nitrogen gas at each point. 在每一位置監(jiān)測排放氮氣的氧氣濃度和露點。c) When the vented gas and dew point of the vented Nitrogen gas at each purge point is below the required levels as defined in section 2 above then close the relevant valve. 當排放氮氣的露點低于第2部分所定義的要求時，關(guān)閉相關(guān)閥門。d) Close all valves on all nozzles, piping and appurtenances. 關(guān)閉所有管口、管道、附件的閥門。e) Close the purge supply valve N15.關(guān)閉吹掃氣體供給閥N15。f) Close the annular purge valve N16. 關(guān)閉夾層放氣閥N166 PRODUCT GAS PURGE產(chǎn)品氣體吹掃6.1 Initial conditions初始條件a) Ensure all permanent pressure and vacuum relief valves are operational. 確保所有的固定壓力和真空解除閥是可使用的。b) Disconnect all temporary piping, if any, associated with Nitrogen purging and dry out. 如果有與氮氣吹掃和干燥相關(guān)的臨時性管道，全部拆除。c) Ensure that all instruments, such as the following are in operational condition. 確保所有儀表是可使用的，例如如下幾種：i. Temperature sensors. 溫度傳感器ii. The tank gauging systems. 儲罐度量系統(tǒng)iii. Pressure sensors. 壓力傳感器6.2 Product Gas purge Zone A (step 5) 產(chǎn)品氣體吹掃區(qū)域A（步驟5）a) Ensure annulus purge valve N16 is closed after Nitrogen purge of inner tank. 確保在內(nèi)罐氮氣吹掃之后夾層放氣閥N16是關(guān)閉的。b) Ensure warm (ambient temperature) Product gas is connected and available to the product supply line either via the process or via the injection point on the pipe rack. 確保環(huán)境溫度下“產(chǎn)品氣體”已經(jīng)通過管線輸送到儲罐，并能滿足吹掃需要量。c) Open the valve on the boil off gas outlet nozzle N6 to vent the Nitrogen gas in the tank, replacing it with warm (ambient temperature) Product gas. 打開管口N6的BOG閥門以排放儲罐內(nèi)的氮氣，用環(huán)境溫度下的“產(chǎn)品氣體”置換罐內(nèi)的氮氣。d) Open the bottom product inlet valve N2 and introduce Product gas into the tank. 打開底部進液閥N2引導(dǎo)產(chǎn)品氣體進入儲罐。e) Warning: ensure that only warm product gas is allowed into the tank at this stage. On no account should cold product be introduced into the line. 確保在這階段中進入儲罐的是環(huán)境溫度下的產(chǎn)品氣體，切莫使冷的產(chǎn)品氣體進入供給線。f) Monitor the concentration of Product gas in the boil off gas line. 監(jiān)測BOG管線上“產(chǎn)品氣體”的濃度。g) When the Product gas concentration reaches 92% open N17 to purge the dome space of Nitrogen. 當“產(chǎn)品氣體”的濃度達到92%，打開N17以吹掃頂部空間的氮氣6.3 Product gas Purge, Zone B (step 6) 產(chǎn)品氣體吹掃區(qū)域B（步驟6）a) When the Nitrogen concentration at N1 7 is less than 8% during purge of the inner tank and roof space as described above, open the valve N16 to commence purging of zone B. 當內(nèi)罐和頂部空間吹掃過程中N17位置氮氣濃度低于8%，打開N16閥門開始吹掃區(qū)域Bb) Monitor the N2 concentration and the dew point of the vented Nitrogen gas at N16. 監(jiān)測N16位置排放氮氣的氮氣濃度和露點c) When the vented gas and dew point of the vented Nitrogen at N16 is below the required levels as defined in section 2 above then close nozzle N 17 and reduce the supply rate of Product gas. The supply rate of the Product gas should be adjusted to avoid over pressurising the outer tank. It is important to purge the annular space slowly to avoid the purge gas tunnelling through the resilient blanket alone. 當排放氣體以及N16位置處排放氮氣的露點低于第2部分所定義的要求時，關(guān)閉管口N17和降低“產(chǎn)品氣體”的供給量，“產(chǎn)品氣體”的供給量應(yīng)被調(diào)節(jié)以避免對外罐施加過多的壓力，緩慢置換夾層是很重要的，要避免產(chǎn)生隧道效應(yīng)。6.4 Product gas purge of nozzles (Step 7)產(chǎn)品氣體吹掃管口（步驟7）a) After closing nozzle N1 7, purge out the nozzles and roof top piping. Open each valve on all nozzles, piping and appurtenances to purge any entrapped Nitrogen. 在關(guān)閉管口N17之后吹掃管口和頂部管道，打開所有管口、管道、附件的閥門以吹掃任何夾帶氮氣。b) Monitor the N2 concentration and the dew point of the vented Nitrogen gas at N16. 監(jiān)測N16位置排放氮氣的氮氣濃度和露點。c) When the vented gas and dew point of the vented Nitrogen gas at each purge point is below the required levels as defined in section 2 above then close the relevant valve. 當各位置排放氣體和排放氮氣的露點低于第2部分所定義的要求時，關(guān)閉相關(guān)閥門d) Close all valves on all nozzles, pump columns, piping and appurtenances. 關(guān)閉所有管口、泵柱、管道和附件處的閥門。e) Close the Product supply valve N2. 關(guān)閉產(chǎn)品氣體供給閥N2。f) Close the Purge valve N16. 關(guān)閉放氣閥N16。g) Close the Boil off gas valve N6. 關(guān)閉BOG閥門N6。h) Re-install blanking flanges for in service arrangement of nozzles where appropriate. 相關(guān)的吹掃管口重新安裝盲法蘭以實現(xiàn)使用中對管口的要求。7 COOL-DOWN冷卻7.1 Initial conditions (step 8) 初始條件（步驟8）a) The tank shall be cooled down at a controlled rate to prevent thermal stressing of the inner tank. 儲罐冷卻應(yīng)受到控制，以預(yù)防內(nèi)罐熱應(yīng)力收縮太大。b) The following parameters govern the operation. 以下因素控制操作要求。i. Inner tank cooling shall be controlled at 3C per hour. Maximum permissible cooling measured at any thermocouple shall not exceed 5C per hour. 內(nèi)罐冷卻控制在每小時3C。在任何熱電偶處最大允許的冷卻率不應(yīng)超過每小時5Cii. The maximum differential temperatures between adjacent thermocouples shall not be greater than 20C. 臨近的熱電偶最大差異溫度值不應(yīng)大于20Ciii. The maximum differential temperatures across all thermocouples shall not be greater than 50C. 所有熱電偶最大差異溫度值不應(yīng)大于50Civ. The tank pressure shall not exceed the operating pressure. 儲罐壓力不應(yīng)超過工作壓力。7.2 Recommended Cooldown using product. 推薦用產(chǎn)品冷卻Assumed start temperature假設(shè)開始溫度35CFlow rate for cooldown spray nozzle冷凝噴嘴流量32 l / min at 3 barFlow rate for cooldown spray nozzle冷凝噴嘴流量42 l / min at 5 barEstimated time for cooldown冷卻估計時間228 hoursEstimated quantity of LNG required for cooldown 185 tonnes冷卻用LNG估計需求量Liquid heel in bottom of tank罐底液體根部300 mmQuantity of LNG foliquid heel LNG液體根部數(shù)量147 m 3Estimated quantity of LNG for liquid heel 62 tonnesLNG液體根部估計數(shù)量Total quantity of LNG LNG總量( cooldown + liquid heel) （冷卻用+液體根部）247 tonnes-120-160-200-40-80400050100150200250LNG Cooldown185 tonnes of LNG requiredTime in Hours32 lp m 3bar 41.9 lp m 5barTank available for the introduction of product7.3 Cool-down process (step 9) 冷卻過程（步驟9）a) Open the valve on the boil off outlet nozzle N6 to allow the Product gas to be discharged. 打開N6 BOG出口使產(chǎn)品氣體排放出來。b) Introduce LNG through the pro