TPS _ K0 Process Overview tghe story explained

TPS _ K0 Process Overview tghe story

1. Resins – Process Overview 12/11/2024

2. Polyethylene Simplified Flow Diagram Steam Strippers Fluid Bed Drier Silos Powder Bin Shaker Sieve Air Decanters Cyclone DSV Reactors Centrifuge Solvent Catalyst Monomers Hydrogen Solvent Water Moist Air Stream Drier

3. Resins Process 1 Reactors 2 Work up 3 Drying 4 Silos 5 Compounding 6 Bulk Loading 7 Solvent system - distillation 8 Tank farms 9 Catalyst 10 Wax 11 Utilities

4. Reactors Resins has 4 * 80 m3 reactors for the production of MH K0 broad molecular weight product. The reactors are run in parallel (at an offset time to each other to enable the work up phase to run as a continuous sequence). Each reactor batch comprises the following phases: Charging of the mother liquor (recovered solvent and alkyl), catalyst (TiCl 3 ) and nitrogen sparging. The reactor start up temperature is set to 74 C . Ethylene is then introduced at low gas rate (2.5 tph) where the reactor reaches a pressure of 200 -350 kPa (important for catalyst particles to break-up). Low gas rate is for 800kg ethylene addition. Comonomer, (Butene for the Natural products and Pentene for PE 100), is then introduced after ~200 kg of ethylene has been added. The amount and rate of comonomer addition varies for the type of product being produced.

5. Reactors (cont.) The ethylene gas rate is increased (typically to 4.5 tph) after the addition of 800 kg of ethylene. The reactor temperature increases to 80 C (the reaction is exothermic) and is maintained at this temperature for the remainder of stage 1 (Prepoly) by jacket and outer-cooler cooling using plant water. The amount of comonomer used varies between 30 kg (for GE4760) and 310 kg (for GF7740F) depending on the grade being produced; as does the overall amount of ethylene used in stage 1(~ 5 tonne for GF7660 and ~ 9 tonne for HDF193). At the end of stage 1 a large quantity of hydrogen is introduced into the reactor (up to 600 kPa for HDF193), and the ethylene gas rate is increased (typically to 5.2 tph) as is the temperature (85 C ). This stage is often referred to as homopoly. At the completion of 22 T of ethylene the ethylene flow ceases and the reactor is allowed to sit for 15 min; it is then is vented down before being transferred to the decanter storage vessel.

6. Reactor control

7. Work Up Work up comprises a Suspension receiver vessel (DSV) 120m 3 and two Decanters, two steam stripping vessels and a centrifuge. The decanters separate the PE slurry from most of the solvent. 2 x Krauss Maffei KVZ80 decanters Operating speed 2000 rpm Rated throughput 25 m 3 ph each (maximum is only 2 * 21 m 3 ph) Feed controlled by variable speed pumps linked to mass flow meter Pumps have suction strainers to remove lumps Powder discharges to screw conveyor rated to 12.5 tph ( wet PE) each Solvent (mother liquor) discharges to V3.

8. DSV and Decanters

9. Steam Stripping The function of the steam strippers is to remove the remaining solvent from the PE powder, this is achieved by steam distillation; powder from the decanters floats on top of a water layer and steam is injected to boil of the solvent. Two Ruhrchemie steam strippers in series maximum operating pressure is 6 kPag ( trip set at 8 kPag) each stripper has 2 steam control valves, rated to 4000 kg/hr steam per valve . Steam to PE ratio is 0.65 each steam stripper has a cyclone designed to separate particles/droplets in the vapour stream vapour goes through one of three condensing exchangers horizontal heat exchanger vertical heat exchanger air heat exchanger product leaving second stripper is conveyed by screw conveyor to centrifuge.

10. Steam stripping graphic

11. Centrifuge The centrifuge is a large spin dryer the function of which is to reduce the moisture content of the wet powder before it enters the drying section. 1 x Escher Wyss Push Centrifuge Model P1000 1033 rpm ( 1200 rpm max) reduces moisture to less than 6% w/w moisture The centrifuge is designed for only 14 tph and is a rate limit to the process– we are currently achieving ~ 16 tph through work up. Water removed from the centrifuge is recirculated back to the strippers.

12. Centrifuge graphic

13. Drying The drying system uses hot air to reduce the moisture content of the powder to less than 0.2 % moisture, it has the following vessels: 1 x stream dryer with dispersion fan fresh air fan design 48000m 3 /hr, 200mm WG, 55KW, 980 rpm (Schilde Leg 900). 36000 m 3 /hr goes to stream drier/9000 m 3 /hr to fluid bed dryer 2 x dryer exhaust fan ( 1460 rpm, 45 KW each) dispersion fan 70 KW, 1467 rpm air stream drier operates with hot leg & cold leg. Average temp 100 C , feed 6% moisture in feed powder/down to 1% moisture in product powder. Combined air flow 36000 m3/hr 1 x Fluid bed dryer: FBD exhaust fan 4.4 m 3 /sec, 200 kPa, 22KW FBD hot air fan 5 m 3 /sec, 580 kPa, 37 KW

14. Air heat exchanger and stream drier

15. Cyclones and Fluid bed drier

16. Powder silos Dry powder from the fluid bed dryer passes over a shaker screen into an air lock and is then transferred to the powder silos. Here full silos are mixed and recycled before being released (based on the reactor Mi results) for compounding. Resins has 10 * 150 t silos (product can feed to all extruders) and has converted 8 * 110 t (old PP) silos (which can only feed to the black extruders). The 150 t (west) silos as stated above can feed all extruders (lines 8, 5 & C) using either Pneumex 1 (up to 12 tph) or Pneumex 2. (up to 12 tph) The 110 t (east) silos can only be used to feed the black lines (5 & C) using either Pneumex 3 (6 tph) or an airlock (5 tph).

17. Silo layout

18. West silos graphic

19. East silos graphic

20. Compounding Resins has 3 compounding lines – all of which are ZSK twin screw machines. Line 8 a ZSK 240 machine is used for the production of all Resins natural grades at rates of 6 – 12 tph (grade dependant; torque limited). The Natural additives are supplied as premixed bags which are manually added to the mix bin. Lines 5 & C both of which are ZSK 160 machines used for the manufacture of black product – predominantly HDF193B ( HCR193B is currently under development). On both extruders the additives are delivered to the mix bin as a masterbatch (transferred as required from silos 7 & 9). Each line is capable of 2.75 tph (in the past this was 3 tph). From each of the extruders the product exits the die plate and is chopped into pellets which are cooled and transported with water to gala driers (where most of the water is separated) then transported by air to the granule silos.

21. Line 8 overview

22. Line 8 extruder

23. Bulk Loading Granular product is directed from each of the extruders to 6 bulk (60 t) silos. 4 of these silos are dedicated to line 8 and 1 each for the black lines. Product is conveyed on an air-belt the loading stations then filled into B double containers (during day hours.) Up to 20 tonne of granular product can be loaded into each container. The majority of our customers now take product in bulk. However some customers still require product in either 25 kg bags or 1 tonne bulk bags. Toll have the facilities to repackage the container products into either of these types.

24. Bulk loading graphic

25. Solvent system Solvent used in the process is a saturated hydrocarbon with a boiling range of 135- 165 C . It is predominantly a nonane, that is supplied in 25 m 3 ISO containers from Shell in Europe (Shellsol D30). The solvent has 2 functions in the polymerisation process; it provides a medium for the reaction to take place (the TiCl 3 solid particles are suspended in the solvent with agitation) and it is used to take the exothermic heat away from the growing polymer particle. Solvent (mother liquor) is recovered from the decanters into V3. A reactor charge is then prepared in V1 & V2 typically with 43 m 3 of (mother liquor) from V3 and 6 m 3 of absorbed solvent. This solvent is heated to ~80 C and a small quantity (~ 30 litres per batch) of diluted Isoprenyl aluminium (IPRA) added. The IPRA has 2 functions in the process it is used to activate the catalyst and it reacts with any water or oxygen impurities in the system (i.e. it is sacrificial to the process).

26. Mother liquor system

27. Solvent distillation Mother liquor not reused in the process (i.e. the excess that is removed from the decanters in V3 and not fed to V1 & V2) passes to the 15 m3 tank (typically 6 m 3 per batch). Solvent removed from the steam stripping process pass through a range of heat exchangers and also flow to the15 m3 tank; which has a weir and the solvent (which floats on top of the water) is then pumped to the tank farm for storage in either the old or the new mother liquor tanks. This solvent stream contains dissolved wax (low molecular weight PE) and some powder. It also has traces of water and needs to be distilled before being suitable to be reused in the process. Solvent from the mother liquor tanks are sent to the evaporator (via a preheater). In the evaporator solvent and water (boil off) are removed from wax which flows to the wax column.

28. Distillation column - graphic

29. Distillation cont. Feed to the distillation system is from the mother liquor tanks (T6103 & T6110) via a heat exchanger then into the evaporator. The solvent and water stream from the top of the evaporator are condensed in a heat exchanger E4162(which is also used to generate steam) and then flow to the distillation column. In the distillation column (which has a series of bubble cap trays) and operates at a temperature range of 145 C at the bottom and 114 C at the top; the water and any low boiling hydrocarbons are separated from the solvent which is removed from the bottom of the column and pumped to T8102 (distilled solvent tank). Water and low boiling hydrocarbons (mainly hexane and any unreacted comonomer – butene & pentene) are condensed through a carbon heat exchangers E4163 &5 and returned to the 15 m 3 tank. Any uncondensed material is sent to a seal pot on the roof of the plant (T4168); again any entrained hydrocarbons are separated from the water and returned to the 15 m 3 vessel. Non condensed gas (butene & pentene) vent to atmosphere.

30. Solvent Purification - graphic

31. Solvent purification To further improve the quality of the solvent for use in the process, distilled solvent (T8102) is sent to 1 of 2 purification towers. These columns are packed with silica gel (KC pearls) which remove polar compounds (again mainly water and some oxygenated compounds) from the solvent. The absorption towers are regenerated after ~ 6000 m3 of solvent is passed through a given tower. This is achieved using steam and then drying the column with hot Nitrogen. Absorbed solvent is then stored in T6104 – this is used as solvent make up to the plant. It is also used as flushing solvent (6 kPa) and sealing solvent (13 kPa).

32. Hydrogenation- graphic

33. Hydrogenation The final stage of purifying solvent is to run the adsorbed solvent through the hydrogenation column. This process removes any unsaturates form the solvent. The hydrogenation column is packed with rhodium nickel – and hydrogen is used to convert any double or triple bonds in the solvent to saturated chains. This solvent is used for alkyl dilution so that only high quality solvent is used for making catalyst. Typically the hydrogenation column only runs for 1-2 weeks at a time (every 6 months) to make up sufficient solvent for the alkyl dilution. The hydrogenated solvent is stored in T6101.

34. Mudhole distillation - graphic

35. Recovery of solvent from plant drains Solvent is recovered from the plant drains, which are designed to take any plant spillages to the sludge pit. Again solvent and any powder pass over a weir and are pumped into S8280 (Sludge tank). In this vessel solvent is removed as a top layer by siphoning (back to the 15 m 3 tank), any powder and wax (middle layer) are transferred to V8280 (mudhole distillation vessel). In the mudhole distillation vessel solvent is removed from any powder / wax via vacuum distillation (in a batch process) and this is also returned to the 15 m 3 tank. The remaining solids are transferred at the end of distillation to a marrel for waste disposal.

36. Tank Farm 1 - graphic

37. Tank farm 1 solvent storage All of the various purities of solvent are stored in tank farm 1. At 4 monthly intervals fresh solvent is brought into the plant in 25 m 3 ISO containers. Usual practice is to import 4 ISO of Shellsol D25 at a time. This is unloaded via a pump with a Nitrogen blanket into 1 of the Mother liquor vessels. In theory this solvent is of very good quality and very low Bromine number so should be good for alkyl dilution. In practice it contains up to 20ppm water (which is picked up during transportation), for this reason it needs to be distilled (or absorbed) before use. 4 of the tanks in TF1 are 500m 3 in volume and T6101(hydrogenated solvent tank) is only 200 m 3 . All of the tanks have a Nitrogen blanket and have the ability to be filled with foam in a case of a fire.

38. Tank farm 2 - Graphic

39. Comonomer storage – tank farm 2 Resins currently use 2 types of comonomer for the production of HDPE, butene for all of the Natural grades and Pentene for the production of pipe. Both comonomers are imported in 13-14 tonne ISO pressurised (with Nitrogen) containers. Butene is imported from Korea (but is available from other sources), while the Pentene is imported from South Africa (which is the only commercial source of this material). Butene is unloaded by a pump to either V6102 or V8101 and then fed to the plant using 1 of 3 pumps, while the Pentene is unloaded into either V6161 or 2. The pentene feed to the reactors is achieved using high pressure nitrogen. Trials have recently occurred with Hexene comonomer (using the pentene system) and while being currently evaluated have produced excellent properties.

40. Tank farm 3 (TiCl 4 )- graphic

41. Titanium tetrachloride storage TF3 TiCl 4 is imported (currently from Korea) and is delivered to the site in 20 t ISO containers. This material is transported under a Nitrogen blanket . Resins unloads a TiCl 4 ISO every 18 months, it is a very corrosive and toxic chemical. Any line breaking with this material requires the use of a disposable suit and gas mask. TiCl 4 reacts with both water and oxygen producing large amounts of HCl vapour and fumes as a white cloud (TiO 2 particles). TiCl 4 + 2H 2 0 TiO 2 + 4 HCl High pressure nitrogen is used to unload the ISO into the storage tank and to feed product into the plant for the manufacture of catalyst.

42. Alkyl storage in TF3 - Graphic

43. Isoprenyl aluminium storage –TF3 Isoprenyl aluminium (IPRA) is imported as a concentrated (~80%) solution in a hydrocarbon solvent (previously this was supplied in hexane), in 1.4 tonne bullets. IPRA in this form is spontaneously flammable in air. Like TiCl 4 it reacts violently with both water and oxygen. Line breaking of material containing the concentrated IPRA requires a aluminised suit with face shield. A concentrated IPRA cylinder is unloaded into ~ 5 m 3 of solvent which dilutes the product to a 20 % solution (below the spontaneously flammable level). Two 15 m 3 storage tanks are available for dilute alkyl T8103 and T8108. Diluted alkyl is pumped into the plant for catalyst make up and for addition to the mother liquor in V1 and V2.

44. Catalyst The catalyst used in the polymerisation process at Resins is TiCl 3 , which is produced by the following reduction reaction of TiCl 4 and IPRA which takes place in the catalyst preparation vessel V4111 at controlled temperature of 0 C . 2TiCl 4 + IPRA 2TiCl 3 + dichlorinated Alkyl The reaction between the titanium tretrachloride and the alkyl is extremely exothermic and takes place in a refrigerated vessel. The TiCl 4 (which is a liquid with very high thermal expansion) is extremely reactive in the presence of oxygen and moisture (the reaction products are hydrochloric acid and titanium dioxide), this is very slowly added via a programmed amount to a diluted solution of the IPRA. Note each mole of Aluminium is able to reduce 2 moles of the titanium. The program is set up to react 60 kg of TiCl 4 with 145 kg of diluted alkyl (which has a concentration of ~ 1.1 mole per kg).

45. Catalyst Manufacture -graphic

46. Catalyst manufacture cont The TiCl 4 addition rate increases as the reaction takes place – It is extremely important that the initial phase of the reduction reaction is kept at a temperature of -2 to +2 C . The catalyst formed is the β TiCl 3 which is a solid that has a brown colour. On completion of the reaction the refrigeration system turns off and the catalyst is allowed to stand for 30 min before it is transferred using 2200 kg of absorbed solvent into 1 of 2 storage vessels V4102 & V4103) where it is allowed to cure for 24 hrs before being tested (a sample is allowed to settle and the liquid is checked for colour) and released (if suitable) to the catalyst feeder vessel V4105. Any batches of catalyst that are rejected need to be decomposed (these are transferred to V4512) and carefully decomposed in V4513 & V4109). 2TiCl 3 + 4H 2 0 2TiO 2 + 6HCl + H 2 It is very important to keep the catalyst system free of air and moisture, the whole catalyst system is maintained under a Nitrogen atmosphere.

47. Catalyst storage and feed

48. Catalyst addition to mother liquor Catalyst from the Catalyst feeder vessel which has a concentration of ~ 0.133 moles per kg is pumped into the mother liquor stream while it is charging a reactor. Approximately 13 moles of the diluted catalyst are added while the 37m 3 of hot mother liquor from V1 & V2 are feeding the next reactor batch.

49. Wax Wax (low molecular weight PE and amorphous product) remains dissolved in the solvent particularly at temperatures of 50 -80 C. At the decanters the majority of the wax produced in the process flows with the mother liquor into V3 and is subsequently fed back to the reactors. Wax in the mother liquor circuit is typically of the order of 3%, but this concentration will vary depending on the amount of comonomer used in the process, the higher the comonomer the greater the concentration of wax. In the distillation circuit the wax is removed from the solvent in the evaporator. From here it is fed to the wax column which has a rotating scraper and the final traces of solvent are boiled from the wax (at a temperature of ~180 C), the wax is collected in 0.5 tonne lined skips. The wax is allowed to cool and solidify in the skip before it is tipped stretch wrapped and the blocks packed into containers for export. The wax is used for road fill and as a filler in cheap extrusion.

50. Wax column - graphic

51. Utilities - Pipeline Resins receives the following utilities via pipeline: Steam from Olefins supplied at 2 pressures; 880 kPa and 4000 kPa which is used in the following; Low pressure (LP) steam at 350kPa (let down from MP steam) – used in the steam strippers as well as some generated in the steam generator (and further reduced to 80kPa) Intermediate Pressure (IP) steam at 1500kPa (let down and desuperheated from HP steam) – used in solvent distillation, hydrogenation and drying air heaters HP steam, nominally at 4000kPa – used in Line 8 Granulation H 2 from BOC (1800 kPa) N 2 from Air Liquide both high & low pressure (1400 & 600 kPa)

52. Utilities- Electricity Resins takes electricity supply from Cogen (at Olefins) but can also be supplied from Powercor Pty Ltd substation AC at 11kv (fault level 350MVA). This comprises two 11kV feeders which are both normally in service. The configuration is such that the plant can run from one feeder at 100% load if required. 11kV is distributed to Polymerisation, Granulation, Workshop, Amenities, and Multipurpose substations. In total the Resins distribution system consists of 14 transformers that supply motors and other loads at 11kV and 415/240V from substations onsite.

53. Utilities - air Instrument Air (IA) and some of the Plant Air (PA) are provided by common supply compressors but are distributed through independent systems to plant users at a nominal 780kpag. The compressors are located in the compressor house on the east side of the decommissioned boiler house. Additional plant air is generated by compressors in the silos for transporting powder from the polymerisation plant to the silos and from there to the granulation plant. Other compressors are located west of the granulation plant. They generate air to transfer the granules from the extruders to the granule silos.

54. Utilities- water Tank T6401 supplies plant water to the Resins Facility taking supply from the municipal water service. T6401 has a capacity of 3 M litres providing process water for cooling water and demineralisation make-up and fire water. 1.2 million litres is reserved as fire water. Resins has 3 cooling towers each with 2 pumps; most of the water for which is supplied via pipeline from the Plastics water recovery system. The fire water supply to process and storage areas takes the form of a ring main, with multiple take-off connections to each unit. Fire Water is supplied by two fire water pumps which take suction from T6401. A jockey or leakage pump maintains ring main pressure to compensate for routine background system leakage.

55. Utilities - Effluent A number of drain points are located throughout the plant that feed to the central effluent drainage system. This directs effluent to either the mixing lagoon, several emergency lagoons or waste holding lagoon depending on the state of the effluent. The mixing lagoon receives aqueous trade waste from various production plants, in addition to all site-generated sewage. With the aid of a floating mixer, the various waste streams are blended to a uniform consistency and then sent to Plastics for further treatment. Returned water from Plastics is used as a cooling tower make up stream. A small stream of water is discharged to the city west water sewer system.