POLYMERISATION METHOD AND APPARATUS THEREFOR

Abstract

A method of assembling and/or operating apparatus for undertaking a chemical reaction. The apparatus includes a housing in which a precursor of a receptacle is arranged. A fluid (F1) may be introduced into said precursor to cause the precursor to inflate.

Claims

1-32. (canceled)

33. A method of assembling and/or operating apparatus for carrying out a chemical reaction, the method comprising the steps of: (i) selecting a housing in which a precursor of a receptacle is arranged; and (ii) introducing a fluid (F1) into said precursor of said receptacle to cause the precursor to distend (e.g. inflate) to define a distended receptacle for receiving reagents for reaction in the apparatus.

34. The method according to claim 33, wherein, in step (i), the precursor of said receptacle is substantially flaccid.

35. The method according to claim 33, wherein said housing has a volume in which said precursor of the receptacle is arranged wherein, in the combination described in step (i), said precursor of the receptacle occupies less than 70%, preferably less than 5%, of said volume.

36. The method according to claim 33, wherein: said housing supports said precursor of said receptacle and/or said distended receptacle; said housing is elongate and, in the combination described in step (i), length (L) of the precursor of the receptacle extends at least 60% (or at least 90%) along the elongate extent of an internal region of the housing in which said precursor of said receptacle is arranged; and said housing is elongate and includes securement means for releasably securing said precursor and/or distended receptacle in position.

37. The method according to claim 33, wherein, in the combination described in step (i), said precursor of the receptacle is secured in position relative to the housing and said precursor of said receptacle comprises a plastic material which comprises optionally-substituted alkylene units.

38. The method according to claim 33, wherein said receptacle includes a first end and a second end which are spaced apart along the elongate extent of the receptacle, wherein said first end is a closed end.

39. The method according to claim 33, wherein the length of the receptacle is the linear distance between a first end and a second end thereof, wherein the diameter of the receptacle is substantially constant for at least 80% of the distance from the first end towards said second end; and wherein a region of the receptacle adjacent said second end diverges so an opening of the receptacle at said second end has a greater diameter than a region of the receptacle inwards of the second end.

40. The method according to claim 38, wherein, other than any means by which the first end of the precursor of the receptacle is arranged to define a closed end, the precursor of the receptacle includes no seams between said first and second ends.

41. The method according to claim 33, wherein the diameter of the receptacle is in the range 1 cm to 45 cm across its entire extent; and/or the length of the receptacle is in the range 3 m to 15 m (and is preferably in the range 4 m to 11 m); and/or the volume of the receptacle is in the range 4000 cm.sup.3 to 0.5 m.sup.3 (preferably in the range 10000 cm.sup.3 to 0.15 m.sup.3).

42. The method according to claim 33, wherein the method comprises clamping the precursor of said receptacle in position, in order to define the combination described in step (i).

43. The method according to claim 33, wherein step (ii) comprises introducing an inert fluid (F1) into said precursor of said receptacle to cause the precursor of said receptacle to distend and define a distended receptacle, wherein, optionally, the method comprises introducing said inert fluid (F1) so it flushes fluid from the precursor of said receptacle so that the level of oxygen within the distended receptacle after introduction of said fluid (F1) is less than a predetermined level.

44. The method according to claim 33 which comprises a step (iii) which comprises introducing a fluid (F2) into the housing between a wall of said housing and an outer surface of the precursor of said receptacle and/or said distended receptacle.

45. The method according to claim 33, wherein said housing includes cooling means for cooling reagents and polymer contained in the apparatus in use.

46. The method according to claim 33, wherein said elongate housing comprises a first elongate tube in which said precursor of said receptacle is positioned, wherein after step (ii) said distended receptacle contacts an internal surface of the first tube, wherein at least 60% of the area of an external wall area of said distended receptacle contacts said internal surface.

47. The method according to claim 46, wherein said elongate housing comprises a second elongate tube which is coaxial with said first tube and said first tube is positioned within the second tube, said first and second tubes being radially spaced apart so an annular gap is defined between the first and second tubes, wherein said annular gap defines a fluid passage for a coolant fluid and, optionally, the annular gap extends around substantially the entirety of the first elongate tube so that coolant fluid can contact at least 70% of the first elongate tube in use thereby to cool the first elongate tube.

48. The method according to claim 47, wherein said first and second tubes are cylindrical.

49. The method according to claim 33, wherein, in the method, the same port is used at different times to introduce both a fluid (F1) into said precursor of said receptacle to cause it to distend and subsequently to deliver reagents into the distended receptacle.

50. The method according to claim 33, wherein apparatus used in the method includes cooling means which includes a container (C1) for containing a cooling fluid, the method comprising delivering coolant fluid from the container (C1) to a region outside said distended receptacle and/or outside a reagent-containing receptacle; and wherein said apparatus includes a container (C2) for containing a monomer, the method comprising delivering monomer into the distended receptacle; and wherein said apparatus includes a container (C3) for containing a catalyst, wherein the method comprises delivering catalyst into the distended receptacle.

51. The method according to claim 50, wherein containers (C2) and (C3) are arranged to deliver monomer and catalyst respectively to a mixing region where they are contacted and mixed, wherein the mixing region is upstream of said distended receptacle.

52. The method according to claim 33, which includes a step (iv) which comprises introducing reagents for preparation of a polymer into said distended receptacle, wherein the total weight of reagents introduced into said distended receptacle is at least 1000 g, wherein said polymer prepared is selected from the group comprising: poly(alpha-olefin), polychloroprene, vinyl acetate polymers and copolymers, poly(alkylene oxide) (PAO), and mixtures thereof.

53. The method according to claim 52, the method comprising undertaking a reaction for a time of at least 10 hours and, subsequently, includes a step of removing a receptacle containing polymer from said housing.

54. The method according to claim 33, wherein a polymer is prepared in said method and the method comprises withdrawing a receptacle containing polymer from the housing and subsequently engaging a new precursor of a said receptacle with said housing and producing a polymer in the new precursor of said receptacle.

55. An apparatus for carrying out a polymerisation reaction to produce a drag reducing polymer, said apparatus comprising a housing in which a distended receptacle is arranged, wherein said distended receptacle is arranged to receive reagents for reaction in the apparatus.

56. The apparatus according to claim 31, wherein said distended receptacle includes a fluid (F1) which is contained within the distended receptacle and/or which causes distension; said apparatus includes a container (C1) for containing a coolant fluid, wherein the apparatus is arranged for delivery of coolant fluid from the container (C1) to a region outside the distended receptacle; said apparatus includes a container (C2) for containing a monomer, wherein the apparatus is arranged for delivery of monomer into the distended receptacle; wherein said apparatus includes a container (C3) for containing a catalyst, wherein the apparatus is arranged for delivery of catalyst into the receptacle; the apparatus includes a mixing device for mixing monomer and catalyst upstream of said distended receptacle; and the volume of the distended receptacle is in the range 4000 cm.sup.3 to 0.5 m.sup.3 (preferably in the range 20000 cm.sup.3 to 0.12 m.sup.3).

57. A method of assembling and/or operating apparatus for carrying out a chemical reaction, the method comprising the steps of: (i) selecting a housing in which a precursor of a receptacle is arranged; and (ii) introducing a fluid (F1) into said precursor of said receptacle to cause the precursor to inflate to define an inflated receptacle for receiving reagents for reaction in the apparatus; wherein said housing has a volume in which said precursor of the receptacle is arranged wherein, in the combination described in step (i), said precursor of the receptacle occupies less than 70% of said volume; said housing is elongate and, in the combination described in step (i), length (L) of the precursor of the receptacle extends at least 90% along the elongate extent of an internal region of the housing in which said precursor of said receptacle is arranged; said precursor of said receptacle comprises a plastic material; wherein the length of the receptacle is the linear distance between a first end and a second end thereof, wherein the diameter of the receptacle is substantially constant for at least 80% of the distance from the first end towards said second end; wherein the diameter of the receptacle is in the range 1 cm to 45 cm across its entire extent; and/or the length of the receptacle is in the range 3 m to 15 m; wherein step (ii) comprises introducing an inert fluid (F1) into said precursor of said receptacle to cause the precursor of said receptacle to inflate and define an inflated receptacle; wherein said housing includes cooling means for cooling reagents and polymer contained in the apparatus in use; wherein apparatus used in the method includes cooling means which includes a container (C1) for containing a cooling fluid, the method comprising delivering coolant fluid from the container (C1) to a region outside said distended receptacle and/or outside a reagent-containing receptacle; and wherein said apparatus includes a container (C2) for containing a monomer, the method comprising delivering monomer into the distended receptacle; and wherein said apparatus includes a container (C3) for containing a catalyst, wherein the method comprises delivering catalyst into the distended receptacle; and wherein containers (C2) and (C3) are arranged to deliver monomer and catalyst respectively to a mixing region where they are contacted and mixed, wherein the mixing region is upstream of said distended receptacle.

Description

[0107] Specific embodiments of the invention will now be described, by way of example, with reference to the accompanying drawings in which:

[0108] FIG. 1 is a schematic representation of apparatus for producing a polymer

[0109] FIGS. 2(a) to 2(d) illustrate, in schematic cross-section, steps involved in producing a plastic reaction tube of the apparatus;

[0110] FIGS. 3(a) to 3(d) illustrate steps involved in assembling the apparatus, including the plastic reaction tube;

[0111] FIGS. 4(a) and 4(b) illustrate steps involved in readying the assembled apparatus of FIG. 3(d) for use in a polymerisation process;

[0112] FIG. 5 illustrates the apparatus being charged for bulk polymerisation;

[0113] FIGS. 6 and 7 show steps in the removal of the plastic reaction tube from other parts of the apparatus; and

[0114] FIG. 8 shows a sealed tube containing polymer;

[0115] FIG. 9 shows a log of polymer removed from the reaction tube;

[0116] FIG. 10(a) is a representation of the apparatus of FIG. 1, but additionally including a thermocouple for monitoring temperature during the polymerisation process;

[0117] FIG. 10(b) is a representation of the thermocouple in side elevation;

[0118] FIG. 10(c) is an end view in the direction of arrow X(c) of FIG. 10(b); and

[0119] FIG. 11 is a schematic diagram of a simplified apparatus for producing a polymer.

[0120] In the Figures, the same or similar parts are annotated with the same reference numerals.

[0121] Referring to FIG. 1, apparatus 2 for carrying out a polymerisation reaction to produce, for example, a DRA involving monomer(s) and catalyst comprises a rigid elongate support tube assembly 4 which includes a coolant containing cooling jacket 6. The jacket 6 includes a coolant inlet 8 and a coolant outlet 10. Within the supporting tube assembly 4 is arranged an inflatable plastic reaction tube 12 (shown in a substantially filled state in FIG. 1) which abuts an internal wall 14 of the support tube assembly 4. End fitting 16 at one end of support tube assembly 4 includes a fluid port 18 via which an inert gas may exit the apparatus. End fitting 20 at an opposite end of support tube assembly 4 includes fluid ports 22, 24 in which fluids (e.g. monomer(s) and/or catalyst(s) and/or inert gas) may be introduced and/or removed from the apparatus during operation. In use of the apparatus, polymer is produced within the plastic reaction tube 12 while the tube 12 is cooled by contact with internal wall 14 of support assembly 4 which is cooled by coolant passing within cooling jacket 6 and while a positive pressure of inert gas is maintained around the tube 12. The contents of the plastic reaction tube may be maintained under inert gas conditions, through the application of inert gas via ports 22 and/or 24 while the polymerisation process is carried out. After completion of the polymerisation, end fitting 20 is removed and the plastic reaction tube 12 containing polymer produced is withdrawn from the assembly 4. The reaction tube 12 (i.e. the plastic material of which it consists) is disengaged, for example peeled, from the polymer to isolate the polymer from the reaction tube. The polymer may then be comminuted and formulated for use as a drag reducing additive.

[0122] Features of the apparatus and associated processes are described in greater detail below.

[0123] FIGS. 2(a) to (d) illustrate steps involved in producing the inflatable plastic reaction tube 12 which, in its finished state, is as represented in FIG. 2(d).

[0124] The reaction tube 12 is formed from 125 μm (500 gauge) lay flat, polyethylene tube 26 which is initially not closed at either end. The tube has a length of about 600 cm plus an additional 5 cm to 10 cm (to enable it to be clamped in position as described hereinafter) and a width of about 153 mm±5 mm when in its flattened state shown in FIG. 2(a).

[0125] In a first step, shown in FIG. 2(b), one end of the tube is heat sealed as represented by number 28, thereby to fully close off the end and define one closed end of a receptacle for a polymerisable mixture.

[0126] In a second step, shown in FIG. 2(c), open end of the tube 26 (opposite the closed end) is stretched (as illustrated by reference numeral 27) over a heated cone 30 thereby to splay the tube in a region thereof towards its open end. As a result, the diameter of the tube 26 adjacent its open end gradually increases on moving from region 32, inwards of the open end, to region 34, situated at said open end.

[0127] In a third step, shown in FIG. 2(d), the cone 30 and tube 26 are disengaged thereby to leave splayed open end 35 which has been permanently deformed by the heat treatment using the heated cone 30.

[0128] The open end is splayed as aforesaid to facilitate securement of the open end within the apparatus in such a way as to minimise air gaps between the plastic reaction tube 12 and associated fittings of the apparatus. If air was to become trapped within folds of the plastic reaction tube 12, such air could be detrimental to the polymerisation process and/or reagents used therein. In addition, the splaying facilitates production of a fluid-tight seal between the plastic tube and fittings of the apparatus.

[0129] The apparatus 2 may be assembled as described with reference to FIGS. 3(a) to 3(d).

[0130] Referring to FIG. 3(a), support tube assembly 4 includes an inner rigid tube 38 arranged within an outer rigid tube 40. Spacers (not shown) are provided between tubes 38, 40 to maintain spacing therebetween thereby to define a passageway 42 between the tubes 38, 40 in which cooling fluid can flow. Ends of the outer rigid tube are welded to the outer surface of the inner rigid tube, to close the ends of the jacket assembly. Coolant inlet 8 communicates with the passageway 42 for passage of cooling fluid from the outside into the passageway 42 via the inlet 8 and out thereof via outlet 10. The cooling fluid can flow within the passageway around substantially the entirety of tube 38, before it exits the passageway via coolant outlet 10. Thus, a cooled, jacketed support tube assembly is arranged around the plastic reaction tube 12.

[0131] Inner tube 38 may suitably be made from stainless steel (e.g. SS304L) of thickness 0.083″ (2.1 mm) and may have an outer diameter of 4″ (101.6 mm). The length may be 20 ft (609.6 cm).

[0132] An inlet 13 (FIG. 1) is provided for introduction of gas into the inside of the inner tube 38 as described below.

[0133] Outer tube 40 may suitably be made from stainless steel (e.g. SS304L) of thickness 0.12″ (3 mm) and may have an inner diameter of 108 mm and an outer diameter of 4.5″ (114.3 mm). The length may be 19 ft 7½″ (598.2 cm).

[0134] Coolant inlet 8 and outlet 10 may be fabricated with a 0.5″ NPT Weldolet (Trade Mark). A push fit adaptor may be used to allow easy connection or removal of tubing for coolant.

[0135] End fitting 16 may comprise a suitable gasket and a sanitary stainless steel end plate with a single tapped thread for the port 18.

[0136] At the left hand end of FIG. 3(a), there is shown a 4″ (101.6 mm) Viton (Trade Mark) tri-clamp gasket 44 and an end plate 46. The end plate 46 incorporates inlets/outlets 22, 24 which may be tapped into the end plate. A push fit adaptor may be provided allowing convenient connection and removal of polyethylene (PE) tubing. Inlet/outlet 24 incorporates a ½″ NPT ball valve. As described hereinafter, during the process described inlet/outlet 24 is used in three different steps—(a) inflation and inert gas flushing of the reaction tube 12; (b) charging of monomer/catalyst mixture; and (c) flushing with inert gas after charging with the monomer/catalyst mixture (to clear delivery lines and provide additional inertion of the apparatus contents).

[0137] Also as described hereinafter, during the process described inlet/outlet 22 may be used as an inert gas outlet during inflation of reaction tube 12, inerting and monomer/catalyst charging; and subsequently as an inlet for inert gas (to maintain a small positive pressure inside the reaction tube 12 for the remainder of the bulk polymerisation process).

[0138] Although in the figures the apparatus is shown with the elongate axes of tubes 38, 40 of the support tube assembly 4 horizontal, it is preferred that the tubes are raised at the left hand end of FIGS. 3(a) to (d) to facilitate flow of fluids from their position of introduction and into the reaction tube 12 defined by tube 26; and to avoid loss of monomer/catalyst via port 22 during charging. Typically the angle defined by tubes 38, 40 to the horizontal is about 2 to 3° (or the gradient is about 1 in 20).

[0139] The reaction tube 12, produced from tube 26 as described in FIG. 2(d), is inserted into the inner tube 38 and pushed thereinto so its heat sealed end 28 is adjacent end fitting 16. As shown in FIG. 3(b), initially the splayed open end 35 protrudes from the inner tube 38. Next, as shown in FIG. 3(c), the splayed open end 35 is turned back over flange 48 produced on inner tube 38. Then, as represented in FIG. 3(d), gasket 44 and end plate 46 are secured in position thereby firmly (and sealingly) clamping the open end 35 in position as represented in FIG. 3(d). Note in FIG. 3(d) sanitary fitting clamps have been omitted in the interests of clarity.

[0140] As will be noted from FIG. 3(d) after insertion of tube 12 (and prior to inflation thereof) the tube is flaccid as represented in FIG. 3(d).

[0141] After assembly of the apparatus as described with reference to FIGS. 3(a) to 3(d), the apparatus may be readied for use, as described with reference to FIGS. 4(a) and 4(b), by inflating the tube 12 and inerting any region of the apparatus which may contact monomer/catalyst subsequently introduced into the apparatus, including indirect contact occurring via gas diffusion through the tube.

[0142] Referring to FIG. 4(a), initially the volume within the apparatus outside the tube 12 and within the inner tube 38 is inerted to a specified level (e.g. less than 0.3% vol oxygen by introduction of inert gas (e.g. nitrogen) via port inlet 13 as represented by arrows in FIG. 4(a). The inert gas exits via port 18. The oxygen content of gas exiting the inner tube 38 may be monitored at a downstream sampling point (not shown) using standard methods.

[0143] Next, the tube 12 is inflated as shown in FIG. 4(b), using an inert gas (for example nitrogen). Inert gas is passed through the tube until the inert gas exiting via port 22 has an oxygen content (e.g. of less than 0.3% vol), measured at a downstream sampling point (not shown). Inflation involves introduction of the inert gas via port 24 into the tube 12.

[0144] The gas circulates within the tube 12 to inflate it and exits via port 22. During inflation of tube 12, inert gas supply via port 13 is stopped. Inflation of tube 12 can be verified by observing gas flow from port 18, resulting from displacement of a gas volume from outside tube 12 due to inflation of the tube 12. Once inflation of the tube 12 has been completed as shown in FIG. 4(b), port 18 is temporarily closed off, while inerting of tube 12 is completed, to prevent air ingress via port 18. Port 18 is reopened prior to charging of monomer(s)/catalyst(s) to the apparatus.

[0145] As an alternative to the sequence of steps described with reference to FIGS. 4(a) and 4(b), the sequence of steps may be interchanged—e.g. the tube 12 may be inflated first and then sealed before inerting the region outside tube 12. Alternatively, the steps of FIGS. 4(a) and 4(b) could be undertaken substantially simultaneously, with a slightly higher gas pressure within tube 12 to keep it in an inflated condition.

[0146] After completion of step 4(b), the apparatus is ready to be charged with reagents and polymerisation undertaken. Referring to FIG. 5, the flow of coolant in the passageway 42 between tubes 38, 40 is progressed by introducing coolant thereinto via inlet 8 and removing coolant therefrom via outlet 10. Next, a monomer/catalyst mixture is introduced into the inflated tube 12 via port 24 thereby to fill tube 12. The polymerisation reaction is then allowed to proceed for an appropriate length of time (typically about 6 days). During this time, coolant is flowed continuously and temperature may be monitored. For example, some apparatus may include a suitably positioned thermocouple 91 (FIG. 10). In addition, a relatively low pressure (approx. 0.5 psi) of inert gas is applied via ports 22 and 13 to ensure the tube 12 (and its polymerising contents) is maintained under an inert atmosphere.

[0147] The monomer(s)/catalyst(s) mixture is suitably arranged to produce an ultra-high molecular weight polymer for use in drag reduction. The polymer may suitably be a polymer and/or copolymer of alpha-olefin(s).

[0148] Using the apparatus, polymer was prepared from 1-decene monomer, as described in Example 1.

Example 1—Production of Polymer

[0149] 1-decene monomer (31.6 kg) was purged with nitrogen for 60 minutes to remove dissolved oxygen which would otherwise be poisonous to the catalyst used. The monomer was passed through a pre-treatment column containing 1.5 kg of a 50:50 mixture of 13X and 5A molecular sieves (which had been pre-dried under vacuum at high temperature). Post the pre-treatment column, the monomer was pumped to a 90 litres stirred and jacketed glass lined reactor which had previously been dried and inerted to 0.3 vol % oxygen or lower.

[0150] The 1-decene was cooled to 5° C. and then 25 wt % diethylaluminium chloride (DEAC) (80.45 g) in heptane was transferred to a Swagelok (Trade Mark) bomb within a glove box. This was then added to the 1-decene under an inert atmosphere to scavenge any residual water or protic impurities. The mixture was then stirred for 20-30 minutes in a 90 litres reactor.

[0151] Inside a glovebox, titanium trichloride aluminium activated TiCl.sub.3(AAD) (3.7888 g), was dispersed with stirring into anhydrous heptane (157.6 ml), anhydrous 1,2-dichloroethane (1.37 ml) and isobutylaluminoxane (IBAO) in heptane (3.5 wt % aluminium content in heptane) (41.4 ml) was added to the catalyst dispersion. The mixture was stirred, then transferred to a Swagelok bomb and subsequently transferred to the 90 litres reactor, whilst maintaining an inert atmosphere, to initiate the Ziegler Natta polymerisation.

[0152] It is found that, on mixing of monomer and catalyst, polymerisation is instantly initiated and thus proceeds rapidly. The mixture was then rapidly introduced using inert gas pressure to the inflated tube 12 via port 24 as described above with reference to FIG. 5.

[0153] The reaction mixture was held within tube 12, as shown in FIG. 5, at a jacket temperature of 5° C. Chilled water was flowed in passageway 42. After 24 hours, the temperature of fluid in passageway 42 was increased and the reaction continued.

[0154] During the entire process, both the outside and inside of tube 12 were kept under approximately 0.5 psi nitrogen pressure by introducing nitrogen via ports 13 and 22 to assist in restricting oxygen ingress into the polymerising mixture.

[0155] At the end of the aforementioned 6 days reaction time, gasket 44 and end plate 46 were disengaged as shown in FIG. 6, to provide access to the tube 12 which contained polymer 50. End plate 16 may optionally also be removed to allow visual inspection of polymer in the tube 12. The tube 12 (and polymer) were then manually withdrawn from inner tube 38, as shown in FIG. 7. During the withdrawal, the open end of tube 26 was closed by a tightly drawn cable tie 52 (or the like). Subsequently, the tube was fully removed to isolate the sealed tube 12 containing an approximately 20 feet (610 cm) log of polymer 50 as shown in FIG. 8.

[0156] The tube 12 (which is made from polyethylene as described) can readily be detached, for example cut and/or peeled away from the log of polymer 50, to thereby produce an isolated log 50 of polymer, as a single piece, as shown in FIG. 9. Substantially no PE residue contaminates the polymer after removal of tube 12 which may minimise contamination of the polymer, and in turn, may be advantageous in downstream uses thereof. Whilst not wishing to be bound by any theory, the ease with which the tube can be cut away from polymer 50 may be related to the fact the polymer has a higher bulk density (approximately 0.85 g/cm.sup.3) than the 1-decene (density 0.74 g/cm.sup.3) starting material which means the polymer tends to shrink away from the wall of the receptacle as it is formed.

[0157] The log of polymer 50 of FIG. 9 may be processed, by known methods and contacted with a carrier to produce a formulation comprising a DRA.

[0158] Other procedures undertaken are described in Examples 2 to 7. Examples 2 to 6 describe procedures for assessing characteristics of polymers produced as described herein and results of such assessments.

Example 2—Determination of Polymer Conversion Percentage in a Polymer Produced

[0159] A disposable aluminium dish was weighed to four decimal places and the weight recorded (A). A sample of the test material (2-3 g) was placed in the dish and the combined weight of the dish and sample also weighed to four decimal places (B). The sample was dried in a vacuum oven (200° C., 0.04 Torr) for one hour, removed and reweighed. This process was repeated until constant weight (C) was achieved.

[0160] The polymer conversion percentage was calculated as follows:

% conversion=(C−A)/((B−A)*D)

where D is equivalent to the percentage purity of the commercial alpha-olefin monomer used/100. For example, D=0.994 for commercial 1-decene of purity 99.4%.

Example 3—Determination of Percentage Drag Reduction of Polymer Produced

Step 1—Preparation of Working Solution

[0161] n-Hexane (˜80 mL) was charged to a 250 mL bottle. A piece of the test polymer was sampled directly from the polymer log, as prepared in the bulk polymerisation reaction and accurately weighed to four decimal places (0.0150-0.0200 g). The polymer was then dissolved in the n-hexane by mixing for 2 days under low shear conditions, to provide a solution (A).

[0162] Solution (A) was then transferred to a clean, preweighed 500 mL bottle and accurately topped up with further n-hexane to provide a final polymer concentration of 100 mg/kg (100 ppm w/w). The sample was manually mixed, avoiding vigorous shaking, providing partially diluted solution (B).

[0163] An aliquot of solution (B) (4 g) was accurately weighed into a clean, preweighed 1000 mL bottle, then accurately topped up with further n-hexane to the target sample weight (400 g). The sample was manually mixed as above to provide working solution (C) 1 mg/kg (1 ppm w/w).

Step 2—Drag Reduction Testing Procedure

[0164] Clean, preweighed collection bottles (1000 mL) were used for collection of liquids during the test runs.

[0165] The test apparatus consisted of a 2 litre pressure vessel, fitted with charging inlet for solvent, bottom run off (used for cleaning purposes at the end of experiments), and a dip leg connected to a length of stainless steel tubing external to the vessel (7 feet length, 6.35 mm OD, 0.89 mm wall thickness). The tubing was fitted with a control valve at the outlet. The pressure vessel was further fitted with an inert gas inlet, connected to a supply line via a precision pressure control valve. This was set at a constant pressure (2.6 psi) for all experiments.

[0166] The vessel was charged with ˜400 g of either working solution (C) as prepared in Step 1, or untreated n-hexane (control sample), then sealed and pressurised with inert gas (2.6 psi) with the outlet control valve closed. This valve was then opened allowing liquid to purge the external tubing, then closed (this liquid was discarded). A preweighed collection bottle (1000 mL) was placed at the outlet, then the valve reopened for 12-13 seconds to allow the liquid to flow again, recording the elapsed time using a stopwatch. The remaining liquid in the vessel was then discarded, rinsing the vessel thoroughly with untreated n-hexane (for test cycles where solution (C) was used).

[0167] The percentage flow improvement (% FI) and percentage drag reduction (% DR) were calculated from the hexane blank flow rate (F0) and the treated sample (solution (C)) flow rate (Fa) as follows:

F0 in g/sec=(collected weight in g)/(time valve was opened in seconds)

Fa in g/sec=(collected weight in g)/(time valve was opened in seconds)

then

% FI=100*(Fa−F0)/F0

% DR=[(1+% FI).sup.1.9−1]/(1+% FI).sup.1.9

Examples 4 to 6—Production of Polymers Using Different Catalyst Amounts

[0168] Three separate bulk polymerisation reactions (Examples 4 to 6 respectively) were carried out using the apparatus described above, with 1-decene as the monomer. The synthesis procedure was identical to that described in Example 1 other than modification of the charges of TiCl.sub.3(AAD), 1,2-dichloroethane, isobutylaluminoxane solution and heptane diluent, to provide different levels of catalyst loading (expressed as ppm w/w of Ti relative to the monomer charge weight). After completion of the bulk polymerisation the reaction tube comprising the polymer was removed according to the procedure above, and the polymer sampled for analysis, as described in Examples 2 and 3.

[0169] For each of the polymer products, polymer conversion percentages were determined for 10 samples, taken from different points within the polymer log. These points were selected to provide information on the consistency of polymerisation along both the long axis and the cross sectional diameter of the polymer log.

[0170] For each of the polymer products, percentage drag reduction (% DR) was determined as described in Example 3 for four samples taken from different points within the polymer log. These points were selected to provide information on the consistency of product performance characteristics along the long axis of the polymer log.

[0171] The results of these experiments are shown in Table 1.

TABLE-US-00001 TABLE 1 Catalyst % polymer conversion % drag reduction Example (ppm Standard Standard No. w/w Ti) Average deviation Average deviation 4 120 87 1 50.49 1.61 5 100 87 1 49.60 0.81 6  80 83 1 51.62 0.68

[0172] The results show that, when bulk polymerisations were carried out using the apparatus described, products with excellent performance characteristics were obtained. The data shows that polymerisation could be successfully achieved using the apparatus, across a range of catalyst concentrations typical for this application. Furthermore, for each individual experiment the data showed excellent consistency in both chemical composition and performance characteristics, throughout the polymerised reaction volume.

Examples 7 to 9—Production of Copolymers

[0173] Three separate bulk polymerisation reactions (Examples 7 to 9 respectively) were carried out using the apparatus described above, with a monomer mixture of 1-hexene and 1-decene. The synthesis procedure was identical to that described in Example 1 (120 ppm w/w of Ti relative to the monomer charge weight) other than the selection of monomers. After completion of the bulk polymerisation the reaction tube 12 comprising the polymer was removed according to the procedure above, and the polymer sampled for analysis, as described in Examples 2 and 3.

[0174] Polymer conversion percentages and percentage drag reduction (% DR) measurements, from multiple points within the polymer log, were taken and reported in identical manner to Examples 4 to 6.

[0175] The results of these experiments are shown in Table 2.

TABLE-US-00002 TABLE 2 Ex- % polymer % drag am- 1-hexene 1-decene conversion reduction ple wt mol wt mol Aver- Standard Aver- Standard No. % % % % age deviation age deviation 7 60.0 71.4 40.0 28.6 87 1 51.92 0.67 8 35.7 48.0 64.3 52.0 88 3 50.90 0.68 9 28.6 40.0 71.4 60.0 89 3 51.66 0.35

[0176] The results show that, when bulk polymerisations were carried out using the apparatus described to make copolymers, products with excellent performance characteristics were also obtained. Similarly to Examples 4 to 6, the data showed excellent consistency in both chemical composition and performance characteristics, throughout the polymerised reaction volume.

[0177] An alternative, simplified, apparatus 110 is shown in FIG. 11. The apparatus 110 for undertaking a chemical reaction comprises an elongate housing 112 and a receptacle 114. The elongate housing 112 includes a cooling means 116 and end fittings 118, 120 which include ports via which fluids may be introduced and/or removed. In use of the apparatus 110, a chemical reaction product is formed within the receptacle 114. Subsequently, the receptacle 114 containing the chemical reaction product is withdrawn from the elongate housing 112.

[0178] Although only one apparatus 2, 110 has been described, an assembly may be provided including multiple apparatuses 2, 110 to manufacture larger amounts of polymer. Such reactors could be filled sequentially or simultaneously, optionally through the use of a manifold system.

[0179] In another embodiment, shown in FIG. 11, apparatus for carrying out a polymerisation reaction may comprise multiple assemblies, each comprising a reaction tube 2 within a rigid tube 38. The assemblies may collectively be surrounded by a single cooling jacket which is arranged to cool all of the reaction tubes concurrently. For example, two or more assemblies, each comprising a reaction tube 2 within a rigid tube 38, may be axially aligned and a single cooling jacket may envelope the tubes. In an alternative, a plurality of assemblies, each comprising a reaction tube 2 within a rigid tube 38, may be in a stacked arrangement, with a single cooling means being arranged to cool the plurality.

[0180] The invention is not restricted to the details of the foregoing embodiment(s). The invention extends to any novel one, or any novel combination, of the features disclosed in this specification (including any accompanying claims, abstract and drawings), or to any novel one, or any novel combination, of the steps of any method or process so disclosed.