Polyester plant precommisioning and start up

Polyester: - Organization of Precommissioning and Start-up - Heating Procedure - Start-up Procedure Content: Organisation of Pre-Commissioning and Start-up 1.1 Definition of Expressions 1.2 Personnel Organisation 1.3 Work Organisation 1.4 Field check and Pre-commissioning of the Chemical plant Pre-Commissioning 2.1 Commission of Equipment 2.2 Pre-Commissioning of Paste Mixing and Espree Reactor 2.3 Pre-Commissioning of Discage Reactor Initial Start-up of Esterification and Polycondensation Normal Operation of Esterification and Polycondensation Normal Shutdown of Esterification and Polycondensation Emergency Procedures Organization of Pre-Commissioning and Start-up: 1.1 Definition of Expressions Field Check / Completion of Erection / Pre-Commissioning / Mechanical Completion / Initial Start-up / Commissioning / Acceptance Field Check / Completion of Erection: The field check is the final check of the erection work For each plant section in which erection work is completed the field check is done by a mixed team usually consisting of erection and process people from BUYER and SELLER side When all checks are completed a protocol is signed by both parties which states that the plant is ready for pre-commissioning Minor points can be settled after completion of erection and must be mentioned in this protocol By signing this protocol the START-UP TEAM takes over the responsibility for the plant from the ERECTION TEAM Pre-Commissioning / Mechanical Completion: The pre-commissioning covers the activities between completion of erection and mechanical completion Each item shall be checked as far as possible to assure that it can fulfil its duty in the running plant Cold checks (calibration, leakage tests, control functions), hot checks (heating, hot bolting, hot vacuum tests) and trial runs has to be done Operator training is done on the job, for heating the plant the shift organisation is established When all preparation work is finished and everything is ready for a safe initial start-up of the plant both parties sign the protocol of Mechanical Completion Organization of Pre-Commissioning and Start-up: 1.1 Definition of Expressions Field Check / Completion of Erection / Pre-Commissioning / Mechanical Completion / Initial Start-up / Commissioning / Acceptance Initial Start Up: Defines a phase of activities after mechanical completion from the first feed of raw material into the first reactor until normal operating conditions are reached Commissioning / Acceptance: The commissioning covers the period from the time when raw material is fed up to the Date of Acceptance It includes the following steps: - initial start up / - optimisation of the plant / - performance test After the successful performance test the protocol of “ plant acceptance” shall be signed by both parties Organization of Pre-Commissioning and Start-up: 1.2 Personnel Organisation Personnel Requirements: The success of commissioning and start-up activities depends to a competent organisation of personnel Such start-up teams should consist of the following elements: Technical operating group: Graduate engineers chosen especially for start-up and later plant operation Plant management group: This should be a mixed team of supervisors, composed of engineers from SELLER and BUYER, as well as delegates from the contractor and the supplier companies Maintenance group: The maintenance group will take over the responsibility for the equipment when the contractor's people have left the site Laboratory group: Should be able to use laboratory equipment as soon as plant testing with product has been initiated Delegates of Sellers and Suppliers: Experts for planning and execution of field check, pre-commissioning and commissioning activities Experts for the respective package units Organization of Pre-Commissioning and Start-up: 1.3 Work Organisation A network plan and a time schedule are indispensable tools for the planning and coordination of the plant start-up activities Every major target can only be reached on schedule when a daily list of job activities is made Each job is checked periodically to establish whether its completion is delayed due to problems or if regular progress has been achieved The problems which arise are discussed during a meeting among the parties responsible A NETWORK plan is used for visualization of the pre-commissioning progress The network plan consists of states (targets and completeness of states in percent) and activities such as field check, dry check, wet check, heating, trial runs, initial runs etc The network plan has to be prepared prior to pre-commissioning activities All sections and the states (targets) must be listed In order to define certain states, the progress according to the activity list is used The pre-commissioning activities are recorded on ACTIVITY LISTS The activity lists are numbered section wise or group wise They are handed over to the plant section leader prior the pre-commissioning respective preparation work With these documents, control over the large number of parallel activities is achieved A time schedule can be evaluated and also revised periodically Organization of Pre-Commissioning and Start-up: Network plan Organization of Pre-Commissioning and Start-up: Network plan Organization of Pre-Commissioning and Start-up: Organization of Pre-Commissioning and Start-up: Precommissioning: Activity List (Excerpt) Pre-Commissioning: 2.3 Pre-Commissioning of Discage Reactor 2.3.4 Heating 2.3.4.2 HTM venting procedure: Carefully instruct the operators on how a vapour system is vented: - first, close all connection valves to the different heating sections - open the main vent valve, which is connected to the HTM vacuum ejector - open the respective vent valve and wait for about minutes - close the vent valve and open the next vent valve, wait for about minutes - finally, close main valve connected to the HTM vacuum ejector and open all connection valves to the different heating section again Attention: - During heating-up, the product room should be open to remove any generated gas or generated vapor in order to avoid damage of the equipment A pressure build-up must be avoided, anyway - When the spray condenser system is not running, ball valve in front of the rupture disc at the spray condenser 22E43 must be open and locked in this position! - The Discage agitator is not allowed to run during heat-up After temperature attaining the operation condition and stable for hours, it can be started at low speed Check the reactor for any abnormal sound and record the no-load power consumption of the agitator - During heating-up the elongation and displacement of the reactor has to be observed It should be within the limits of “ Mechanical Handbook ” - Heating system and equipment have to be observed continuously during heating-up in view to tightness and extraordinary occurrences Pre-Commissioning: 2.3 Pre-Commissioning of Discage Reactor 2.3.4 Heating 2.3.4.3 Preparation of the Discace reactor: Precalculate the thermal expansion of the Discage reactor and melt pipes Put marks on the pads of the Discage reactor Loosen and/or remove the foundation screws (to be executed only at free ends) of the equipment as per description in the Mechanical Catalogue Prepare the melt filter as per description in the Mechanical Catalogue Remove the locks of spring hangers Ensure that sliding plates and fixed supports of melt distribution lines are in proper conditions Normally the Discage reactor will expand to the required level, in case, it is not expanded according to the calculation, situation needs to be analysed Preconditions: - The Wet Check of section Discage reactor is completed - Level calibration for Discage reactor is completed - Part or all water from Discage reactor (from level calibration) is drained - The HTM plant is in operation and the HPD system is circulating Due to the low energy consumption the plant will be controlled in the on-off mode All low boilers of the liquid HTM system are removed - The HTM evaporator 22E25 is running - The liquid systems HSA, HSB are running Pre-Commissioning: 2.3 Pre-Commissioning of Discage Reactor 2.3.4 Heating 2.3.4.3 Preparation of the Discace reactor - Preconditions: - The WCT cooling system for the agitator shafts, the scrapper and oscillating receivers is running - The quench pots for the sealing systems of the Discage reactor’ s shafts and at the spray condenser 22E43 are filled with EG - Make sure that the EG spray systems consisting of EG spray condensers, EG hot wells, pumps and coolers are in operation - Check the current level in spent EG tank and compare free volume with the EG quantity in the Discage reactor - The agitator of Discage reactor is not running - Nominal nitrogen flow in the Discag reactor through measuring manifold (22FI405) and level measuring device (22LT401 / 22LT405) are present - Prepare trends at the process control system to get a fast overview of the state of heating Start recording the measurements of all relevant process parameters from the process control system and in the field manually every 30 minutes The log of recorded process parameters, need to be supervised by the responsible section leader The condition ready for heating-up must be confirmed by the Start-up manager and the Plant Manager Pre-Commissioning: 2.3 Pre-Commissioning of Discage Reactor 2.3.4 Heating 2.3.4.4 Checking of Emergency Drain Valves: (same then mentioned: Pre-Com Espree reactor) For testing purpose, the emergency drain valve must be dismantled from the HTV piping system The sealing must be cleaned carefully and lubricated before testing Afterwards the respective emergency drain switch at the emergency drain box is activated and the valve’ s function visually checked Then the emergency drain valve is closed again, carefully cleaned and reinstalled in the pipe Remark: If the emergency drain valve is activated without a thoroughly cleaning, it can not be avoided that dirt settles down and damage the valve’ s sealing when operated During further test open this valve only when absolutely necessary! Check the tightness after use If the HTM evaporator has to be refilled frequently during normal operation and without opening the vent valve (loss of HTM), the emergency drain valve might have a leakage Pre-Commissioning: 2.3 Pre-Commissioning of Discage Reactor 2.3.4 Heating 2.3.4.5 Filling of HTM Evaporators: (same then mentioned: Pre-Com Espree reactor) The filling of the HTM evaporators is a standard procedure, which is the same for all HTM evaporators The given sequence must be followed strictly: - Remove the foundation screws on one side of the evaporator Check that the thermal expansion is not restricted by concrete - Complete a tightness test for each evaporator system Emergency drain valves must not be operated in dry state They remain in closed position - Together with the tightness test check the pressure instruments (interlocks!) - Complete a vacuum test for the evaporator systems Oxygen causes thermal degradation of HTM in hot condition Therefore use nitrogen for pressurising and for breaking vacuum - Evacuate the evaporator with vacuum ejector 61J54 of HVV system in order to remove almost all air / oxygen from HTV system - Check if pressure in the HTM evaporators is < 100 mbar abs - All HVV vent valves of the HTV system remain open - For filling 22E25, open valve C557 and then filling valve C553 - Observe level increase on the floating leveling panel 22LI407 - Fill the evaporator in such a way that the 22LAL407 alarm just disappears (thermal liquid expansion during heating) Mark the level on the floating leveling panel - As soon as the low level alarm 22LAL407 disappears, close the filling valve C553 and C557 - Observe level for some time to assure that no drain / filling valve has inner leakage Pre-Commissioning: 2.3 Pre-Commissioning of Discage Reactor 2.3.4 Heating 2.3.4.6 Heating-up of Discage reactor and HSB System: The condition READY FOR HEATING-UP must be confirmed by the start-up leader and the plant manager 2.3.4.6.1 First Step Heating and Evaporation of EG with Primary HTM: - Keep the temperature controllers in manual control mode Fully open the control valves (MV=100%) For control valves with bypass the initial heating is done through the bypass Thus, the manual inlet valve to the control valve is closed to protect seat and plug from the dirt which is generated by heating and flushing the liquid system during initial heating - Open the valve to get a heating rate of 5° C per hour on the Discage reactor - Record all temperatures periodically - Increase temperature of the primary system (heating plant) by preferably 10 ° C per hour / but max 20° C per hour until vacuum boiling point of evaporators is reached The temperatures will start to rise from bottom to top (top of evaporator up to vent vessel) The HSB temperature will follow the primary temperature - Slowly (5° C per hour) increase the setpoint of the primary system until a moderate boiling of EG in the Discage reacor is reached Observe the reactor levels and the levels in the distillate receivers (22D43 and 37S90) Supervise the temperature of the plate heat exchangers, a maximum temperature of 50° C is allowed Pre-Commissioning: 2.3 Pre-Commissioning of Discage Reactor 2.3.4 Heating 2.3.4.6.1 First Step Heating and Evaporation of EG with Primary HTM: - When the vent temperature reaches a value 10° C below the HTM vapour temperature, the vent valve of the respective system can be closed However, vent when the temperature drops again - Check the heating state of critical points in the field (portable thermometer) - At the boiling point of EG compare all thermometers The function of the sensors and their measuring range can be confirmed now (no calibration necessary) - Check periodically the HTM level in all evaporators and refill if required - The product temperature in the Discage will increase to approx 196° C and will remain constant as long as EG remains in the reactors (atmospheric boiling point) - Due to different thermal expansion coefficients the flange connections get loose during heating This is the first stage of hot bolting (200° C) Check that tightening of flange screws is done crosswise with the respective torque meter (see Codes and Standard / IN 40.2003) and that also flanges with difficult access are properly tightened - Close the bypass to the control valves and open flow through the control valves after the liquid systems are thoroughly flushed with HTM - Put the HTM temperature controllers in AUTO mode at the actual operating condition (cascade control) - After EG is evaporated, maintain 200° C for certain time (during first hot bolting) - Increase the temperature of the primary HTM system (61TIC… ) to normal operating condition (340° - 345° C) in steps of 10° C per hour Pre-Commissioning: 2.3 Pre-Commissioning of Discage Reactor 2.3.4 Heating 2.3.4.6.1 First Step Heating and Evaporation of EG with Primary HTM: Before heating, make sure everything concerning safety is organised and considered ! For e.g., During hot bolting: - Safety clothing has to be worn - Helmet with transparent face protection - Heat resistance protective gloves with long shafts - Jacket with long sleeves - Safety shoes - etc Attention: The heat-up rate can be extremely high when all EG is evaporated It is in the responsibility of the plant leader to set the respective alarms and to supervise the operators to avoid any excessive heating rate Pre-Commissioning: 2.3 Pre-Commissioning of Discage Reactor 2.3.4 Heating 2.3.4.6.2 Second step of heating: - All temperature controllers are in AUTO mode - Increase the temperature in the Discage reactor by 10° C per hour up to the normal operating condition (for Discage reactor, HTV temperature 22TIC406 = 285° C and melt distribution HSB = 290° C) - Switch the pressure controllers to AUTO mode when HTM reaches atmospheric boiling point - Maintain the temperature on the given level This is the second stage of hot bolting Use torque meter for final tightening of screws Refer to document IN 40.2003 Bolting Tightening Torques in the file Codes and Standards - After the second hot bolting (~ 285° C): maintain temperature for hot vacuum tests Attention: Due to low heat consumption the heating plant will run in the on-off mode This causes temperature fluctuations in the primary HTM system which disturb the temperature control Pre-Commissioning: 2.3 Pre-Commissioning of Discage Reactor 2.3.5 Hot Vacuum Test Follow the instruction given in the Operating Manual „ Pre-Commissioning of Discage Reactor “ Vol 3, point and in the Start-up Activity list The Hot Vacuum Test is applied for the Discage reactor system This system must be closed by closing the respective valves or using blinds Closing the Discage reactor systems with blinds means, creating abnormal operating conditions These abnormal operating condition require the complete attention of the plant engineers, plant operators and start-up specialists It is absolutely essential that all people involved in the preparation and execution of the tightness test knows the respective paragraphs in the operating manual thoroughly Before the Hot Vacuuum Tests of the individual systems are started, make sure that the systems are completely dry Make also sure that the vacuum system consisting of booster ejectors and vent groups, including the connected condensers are working properly and steam supply available Pre-Commissioning: 2.3 Pre-Commissioning of Discage Reactor 2.3.5 Hot Vacuum Test Before starting the Hot Vacuum Test of the system, all detachable connections of the system must be checked for completeness and correct fastening, for e.g.: - Discage reactor system: Insert a figure-8 blind in barometric leg of the EG spray condenser 22E43 at nozzle N1 of hotwell 22D43, and in barometric leg between the mist eliminator 22E46 and the nozzle N4 of hotwell 20D36 Thoroughly make inspections of all systems concerning Safety, for e.g - Before testing the discage system, the ball valve between spray condenser 22E43 and its associated rupture disc has to be open The ball valve must be locked in “ open” position, so that the plant operators are not able to close the ball valve by mistake Check that the rupture disc is correct installed Pre-Commissioning: 2.3 Pre-Commissioning of Discage Reactor 2.3.5 Hot Vacuum Test The procedure for Hot Vacuum Test is similar to the procedure for Cold Vacuum Test: Suck vacuum for the system in combination with the spray condensers As soon as the required vacuum is reached, close the respecive control valve and observe the pressure increase over a period of 24 hours (consider temperature fluctuation) and observe for leakages If the barometric leg of the EG spray condenser gets cold, this indicates that some condensate has been collected above the figure-8 blind in the barometric leg This condensate is evaporating and may freeze under vacuum By heating the barometric leg, from outside with steam, the condensate can be prevented from freezing and will evaporate faster If the condensate is not completely evaporated, it can negatively influence the result of the cold vacuum test Normally following vacuum is applied to the Discage reactor system: mbar a Pre-Commissioning: 2.3 Pre-Commissioning of Discage Reactor 2.3.5 Hot Vacuum Test The pressure increase (Leak rate) is calculated as follows: Ä p [Pa] x V [litre] Leakage rate [Pa *l/s] = T [s] Ä p = pressure increase in Pa V = system volume in litre T = time in seconds The hot vacuum test of the Discage reactor system is stated to be successful, if the leakage rate does not exceed the value of 100 Pa*l/s This means: System: - Discage reactor incl spray system: Volume: 156’ 390 litre Max allowable pressure increase: 2.3 Pa/h (0.023 mbar/h) Pre-Commissioning: 2.3 Pre-Commissioning of Discage Reactor 2.3.5 Hot Vacuum Test In case of exceeding the allowable pressure increase, the hot vacuum test has to be interrupted and the leakage search with Ammonia or Helium has to be started -> see Op Manual, Vol 3, pt 9.6.4: Procedure for Helium Test -> see Op Manual, Vol 3, pt 9.6.5: Procedure for Ammonia Test After searching and eliminating of leakages, the Hot Vacuum Test procedure has to be repeated, until the leakage rate does not exceed the value of 100 Pa*l/s Means: - Discage reactor system: leakage rate: ≤ 2.3 Pa/h (≤ 0.023 mbar/h) Pre-Commissioning: 2.3 Pre-Commissioning of Discage Reactor 2.3.6 Trial Run 2.3.6.1 General The trial run includes the tests and activities which are described generally in the Operating Manual Vol 1A, Register 6: Organisation of Pre-Commissioning and Start-up, Doc No IZ-11916, 6.5.6: Trial Run 2.3.6.2 Trial run of vacuum unit (capacity check): In principal, sucking ambient air through a temporarily installed flow orifices (several orifices with different flow rates will be used to check the suction characteristic) performs the trial run of the vacuum unit The load characteristics of all ejector units are measured and recorded on diagrams During production, for vacuum disturbances or for ejector maintenance, these data are most important to detect the bad performing unit of vacuum system, i.e which ejector or spray condenser is dirty or has problem It is advisable to the vacuum unit trial run prior to the hot vacuum test 2.3.6.3 Trial run of Discage reactor system: Normally no trial run of the Discage reactor system is done ... operating group: Graduate engineers chosen especially for start- up and later plant operation Plant management group: This should be a mixed team of supervisors, composed of engineers from SELLER and BUYER,... Pre-Commissioning and Start- up: Organization of Pre-Commissioning and Start- up: Precommissioning: Activity List (Excerpt) Organization of Pre-Commissioning and Start- up: Pre-Commissioning Standard Steps... equipment The Wet Check includes: - The start- up and run-in of pumps - The operation of pump circuits - The start- up and run-in of agitators - The start- up and run-in of other machines - The function