Polyolefin production process with improved post reactor processing

Abstract

The invention is directed to a process and a system of producing polyolefin in a gas phase reactor using at least two cyclones in the post reactor processing units. The invention further relates to the use of a system for the production of such polyolefin using a gas phase reactor.

Description

POLY0077-WO-ORD1POLYOLEFIN PRODUCTION PROCESS WITH IMPROVED POST REACTOR PROCESSINGFIELD OF INVENTION

[0001] The present invention is directed to a process and a system of producing polyolefins and in particular polypropylene, in a gas phase reactor and having improved post reactor processing.BACKGROUND

[0002] Operating conditions and systems employed in post reactor units (i.e units downstream to the polymerization reactor) play a critical role in ensuring efficient production process of polyolefins. The problems faced in operation for a gas phase reactor is completely different for a solution or slurry phase polymerization reactors. For example, the gas phase polymerization process for the production of polyolefins such as polypropylene (PP), typically includes a Product Receiver unit (PRs) and product purge bin (PPB) unit that are placed downstream to the polymerization reactor. The product receiver unit typically includes over one hundred filter bags (or simply, filters) to disengage gas and solid particles from the gas-solid mixture that emerges from the gas phase reactor. The product receiver unit functions as a degassing unit and is designed to remove interstitial or dissolved hydrocarbons lodged in the solid polymer particles using nitrogen gas and filters using a stripping gas such as nitrogen and the series of particulate filters. The solid particulate once separated in the Product Receiver unit, flows to the product purge bin (PPB) while the gas recovered in the product receiver (PR) unit, flows to a vent recovery system.

[0003] Over time, the filters present in the Product Receiver unit often get plugged due to particulate deposits. Plugging of filters cause an increase in operating pressure in the Product Receiver (PR) unit and can also cause an increase in pressure drop across the filters. Further plugged filters often result in collapsing of filters, causing solid particulates to enter the vent recovery system, which may lead to major operational hurdles including equipment failure and unplanned production shutdowns. To avoid such shortcomings, plant operators typically have to replace the filters every two years, which in turn leads to regular plant shutdowns as well as increased operating costs. Besides, the replacement of large number of filters (such as over 100 filters) not only adds to operational cost but also prolongs the maintenance time and reactor shut down time.POLY0077-WO-ORD2

[0004] In the past attempts to improve the operations of a Product Receiver unit (PR) by altering its operating conditions or by altering the designs of filters have led to limited success including the occasional premature filter failures leading to unexpected downtime. As a further consideration, it is advantageous to keep the solid particles flowing to the Product Receiver unit (PR) to be kept minimal in order to improve the workings of the mechanical delumpers which are designed to break uneven particle agglomerates to smaller particle sizes. Accordingly, smaller the particle size entering the PR section more efficient would be the delumper in its operation.

[0005] In addition to the product receiver (PR) unit, any inefficient separation of solid / gas mixture in the post reactor phase may also affect the operation of the product purge bin (PPB) unit, which receives the stream from the product receiver (PR) unit. The product purge bin is designed for stripping any further residual hydrocarbon gas to trace levels prior to pelletizing the polyolefin particles.

[0006] Accordingly, one or more objectives of the present invention is to provide for a process and a system for the production of polyolefins in a gas phase reactor that leads to efficient solid gas separation in the post reactor processing units such as the degassing or the product receiver (PR) unit and the purge bin unit. Yet another objective of the present invention is to minimize the number of particulate filters in the product receiver (PR) unit and the size of product receiver (PR) unit of a polyolefin production system while still maintaining the desired solid / gas separation.BRIEF DESCRIPTION OF THE DRAWINGS

[0007] For a more complete understanding, reference is now made to the following descriptions taken in conjunction with the accompanying drawings, in which:

[0008] FIG. 1 is a schematic diagram illustrating an overview of the system for the production of polyolefins having two cyclone units positioned between the olefin polymerization unit and the Product Receiver (PR) unit and operating in-parallel.

[0009] FIG. 2 is a cross-sectional view of the cyclone unit 5.

[0010] FIG. 3 is a cross-sectional view of the cyclone unit 6.

[0011] FIG. 4 is a cross-sectional view of the cyclone unit 5 and / or 6 indicating the various features of a cyclone in detail.POLY0077-WO-ORD3DETAILED DESCRIPTION OF THE INVENTION

[0012] The one or more objectives of the invention is achieved by a process for producing polyolefin comprising the steps of:(i) obtaining a polymer stream (4) from an olefin polymerization unit (1) comprising a gas phase reactor (la) and a product discharge section (lb);(ii) supplying at least a portion of the polymer stream (4) into at least two cyclones (5) and (6) independently such that the stream (7) is introduced into the cyclone (5) through the cyclone inlet (9) and the stream (8) is introduced into the cyclone (6) through the cyclone inlet (10);(iii) recovering a stream (11) from the bottom section (5a) of the cyclone (5) and recovering a stream (12) from the bottom section (6a) of the cyclone (6);(iv) supplying each of the stream (11) and stream (12) into a purge bin unit (13);(v) recovering a stream (14) from the top section (5b) of the cyclone (5) and recovering a stream (15) from the top section (6b) of cyclone (6);(vi) introducing at least a portion of each of the streams (14) and (15) into a product receiving unit (16) and subsequently recovering a stream (17);(vii) supplying at least a portion of the stream (17) into the product purge bin unit (13); and(viii) subjecting each of the streams (11), (12) and (17) introduced in the product purge bin unit (13) to conditions of stripping to obtain a product stream (18) comprising the polyolefin.

[0013] Preferably, the number of cyclones is two and the polymer stream (4) is supplied into the two cyclones (5) and (6) independently such that the stream (7) is introduced into the cyclone (5) through the cyclone inlet (9) and the stream (8) is introduced into the cyclone (6) through the cyclone inlet (10). Preferably, the polyolefin is polypropylene, polyethylene or copolymers thereof. It is particularly preferred that the polyolefin is polypropylene having a particle density ranging from > 500.0 and < 700.0 kg / m3, determined in accordance with ASTM D1895-17.

[0014] Advantageously, the process of the present invention now enables an efficient separation of solid-gas mixture in the post reactor units of product receiver (PR) unit (16) and thePOLY0077-WO-ORD4 product purge bin unit (13). As described in the present invention, the use of at least two cyclones (5) and (6) operating in-parallel and in tandem with the product receiver (PR) unit (16), enable the efficient separation of solid polymeric particles and hydrocarbon gas. It is particularly advantageous to position the cyclones between the olefin polymerization unit (1) and the product purge bin (PPB) (13) to enable the effective separation of the polymer particles and interstitial hydrocarbon gas contained in them. In other words, the cyclones are positioned down stream to the olefin polymerization unit and is adapted to receive the solid polymeric particles and interstitial hydrocarbon gas emanating from the olefin polymerization unit.

[0015] Advantageously, the cyclones achieve a separation efficiency close to 100% for particles greater than 15 microns in diameter and require low maintenance to handle non-abrasive polyolefin particles. Further, in accordance with the present inventive process of using the cyclones (5) and (6) at a specific position, will significantly reduce the quantity of solid particles reaching to the product receiver unit (16). In addition, it is expected, that the inventive process using the cyclones (5) and (6) will reduce the shutdown frequency significantly to once every decade or even lower for the purpose of plant maintenance.

[0016] As an additional benefit, the number of particle filters to be used in the product receiver (PR) unit (16) and the dimensions of product receiver unit (16) can be reduced significantly in accordance with the inventive process - resulting in reduction of both capital and operational expense. For example, the filtration chamber (23) of the product receiving unit (16) has less than 100 particulate filters, preferably less than 50 particulate filters, preferably less than 25 particulate filters and greater than 10 particulate filters. Such a design involving the reduced number of filters, help in reducing both capital and operational costs while still ensuring the desired efficiency in processing.

[0017] A possible way to gauge the separation efficiency of the cyclone (5) and (6) is by evaluating the amount of fine particles and the volume of hydrocarbon gas present in streams (14) and (15) that originates from stream (4). The stream (4) comprises a mixture of polymeric particles and hydrocarbon gas that are produced in the olefin polymerization reactor while streams (14) and (15) are streams comprising primarily of hydrocarbon gas originating from stream (4) and obtained by removing interstitial or dissolved hydrocarbon gas present in the polymeric particles introduced into the cyclones (5) and (6).POLY0077-WO-ORD5

[0018] Lower the polyolefin particulate content in the streams (14) and (15) compared to stream (4) - better is the efficiency of the cyclone in the separation of solid and gas. Conversely higher the hydrocarbon gas content in streams (14) and (15), the better is the stripping efficiency of hydrocarbons in the cyclones.

[0019] In an aspect of the invention, the polymer stream (4) comprises a mixture of polyolefin particles and hydrocarbon gas, wherein the polyolefin particles has a particle size distribution (d30) ranging from > 200 and < 300 pm and a particle size distribution (d99) from > 500 and < 1500 pm, wherein particle size distribution is determined using dynamic light scattering; and wherein the hydrocarbon gas has a density between >1.0 and < 5.0 kg / m3and a gas viscosity of > 5.0 x 10'6and < 2.0 x 10'5kg / m / s.

[0020] In yet another aspect of the invention, each of the streams (14) and (15) comprises > 0.15 wt.% and < 0.5 wt.% of the polyolefin particles present in the polymer stream (4) and > 99.5 wt.% and < 99.85 wt.%, of the hydrocarbon gas present in the polymer stream (4); and wherein the each of the streams (14) and (15) has a particle size distribution (d99) of > 8.0 pm and < 20.0 pm.

[0021] The term particle size distribution (d30) means 30% of all particle size has a size not greater than > 200 and < 300 pm. The term particle size distribution (d99) means 99% of all particle size has a size not greater than > 500 and < 1500 pm. The particle size may be measured by any known standard method such as Dynamic Light Scattering.

[0022] On the other hand, the efficiency of the cyclone separation may also be evaluated by evaluating the amount of polyolefin particles present in the streams (11) and (12). Higher the solid particulate content originating from stream (4) better is the efficiency of the cyclone in separation of solid and gas. Conversely lower the hydrocarbon gas content in streams (11) and (12), better is the hydrocarbon stripping efficiency.

[0023] Preferably, the streams (11) and (12) comprises > 99.5 wt.% and < 99.85 wt.% of the polyolefin particles present in the polymer stream (4) and > 0.15 wt.% and < 0.5 wt.% of the hydrocarbon gas present in the polymer stream (4); and wherein the each of the streams (11) and (12) has a particle size distribution (d99) of > 500 and < 1500 pm.

[0024] The stream (4) emerging from the olefin polymerization unit (1) may be split in a manner so as to independently introduce the contents of stream (4) into the two more cyclones.POLY0077-WO-ORD6For example, the streams (7), (8) have identical chemical compositions, each derived from stream (4) and subsequently introduced into cyclone (5) and (6).

[0025] Preferably, the stream (7) and the stream (8) are each introduced into the cyclone at a cyclone inlet velocity ranging from > 15.0 m / s and < 25.0 m / s; and / or wherein the streams (14) and (15) are each recovered from the top sections of the cyclone (5b), (6b) at a cyclone outlet velocity ranging from > 40.0 m / s and < 60.0 m / s.

[0026] The cyclone may be operated at a suitable operating condition. For example, the cyclone (5) and (6) are operating under the conditions of:(a) an average residence time for stream (7) and stream (8) ranging from > 5.0 and < 35.0 seconds;(b) a cyclone inlet temperature of > 50 °C and < 60 °C;(c) a cyclone inlet pressure of > 60 and < 100 kPag; and(d) an average volumetric gas flow rate of > 80 and < 240 m3 / min; and(e) a cyclone inlet solid loading of > 6.0 and < 43.0 kg of solid polyolefin parti cles / m3of hydrocarbon gas.System for producing polyolefins

[0027] In an aspect of the invention, the invention relates to a system for producing polyolefin according to the process of the present invention. In an aspect of the invention, the invention relates to the use of the system of the present invention for improving polyolefin parti cle- hydrocarbon gas separation in a polyolefin production process while reducing the number of filters in product receiving unit by at least 50%, preferably up to 90%.

[0028] The system comprises: a) the olefin polymerization unit (1) positioned upstream and operably connected to at least the two cyclones (5) and (6) such that the cyclone inlet (9) is adapted to receive stream (7) and cyclone inlet (10) is adapted to receive stream (8); b) the product receiving unit (16) positioned downstream to each of the cyclones (5) and (6); wherein the top section (5b) of cyclone (5) is operably connected to the product receiving unit (16) and the top section (6b) of cyclone (6) is operably connected to the product receiving unit (16); andPOLY0077-WO-ORD7 c) the product purge bin unit (13) positioned downstream to each of the cyclone (5), cyclone (6) and to the product receiving unit (16), wherein the bottom section (5a) of the cyclone (5) is operably connected to the product purge bin system (13) and the bottom section (6a) of the cyclone (6) is operably connected to the product purge bin system (13).

[0029] It is particularly preferred that the olefin polymerization unit (1) comprises a gas phase reactor (la).The olefin polymerization unit.

[0030] Preferably, each of cyclones (5) and (6) are in fluid communication with a product discharge unit (lb) of the olefin polymerization unit (1) such that the product discharge unit (lb) of the olefin polymerization (1) is positioned upstream to each of the cyclones (5) and (6) and downstream to the gas phase reactor (la).

[0031] The gas phase reactor (la) may have four product discharge units (lb) grouped as two pairs (pairs A and B) that discharge the stream (4). The two product discharge units of each pair may be operated in the normal parallel or alternating sequence mode or separately in case of mechanical problems occurring with one discharge system.

[0032] The particulate polyolefin polymer is for example formed in the gas-phase polymerization reactor by homopolymerizing an olefin or copolymerizing an olefin and one or more other olefins. The polymerization may be carried out at temperatures from 20 to 200°C, preferably from 30 to 160°C, and in particular from 65 to 125°C and at pressures from 0.5 to 10 MPa, preferably from 1.0 to 8 MPa and in particular from 1.5 to 4 MPa, wherein these pressures, as all pressures given in the present disclosure, have to be understood as being absolute pressures, i.e. pressure having the dimension MPa (abs).

[0033] Suitable gas reactors are, for example, stirred gas-phase reactors, multizone gasphase reactors, or gas-phase fluidized-bed reactors. Such reactors are generally known to those skilled in the art. Stirred gas-phase reactors can, for example, be horizontally or vertically stirred gas phase reactor. In another embodiment of the invention, the gas phase reactor may be a horizontal or a vertical gas phase reactor without the need of stirring. Preferably, the gas phase reactor is a vertical gas phase reactor or a horizontal gas phase reactor without stirring.

[0034] Preferred reactors are fluidized-bed reactors, i.e. reactors comprising a bed of polymerizing polyolefin particles which are kept in fluidized state by introducing a gas fromPOLY0077-WO-ORD8 below. This gas is then usually taken off at the upper end of the reactor, cooled to remove the heat of polymerization and recirculated back into the reactor at its lower end.

[0035] Preferred reactors are further multizone circulating reactors which are, for example, described in WO 97 / 04015 and WO 00 / 02929 and have two interconnected polymerization zones, a riser, in which the growing polyolefin particles flow upward under fast fluidization or transport conditions and a downcomer, in which the growing polyolefin particles flow in a densified form under the action of gravity.

[0036] The polyolefin particles leaving the riser enter the downcomer and the polyolefin particles leaving the downcomer are reintroduced into the riser, thus establishing a circulation of polymer between the two polymerization zones and the polymer is passed alternately a plurality of times through these two zones. It is further also possible to operate the two polymerization zones of one multizone circulating reactor with different polymerization conditions by establishing different polymerization conditions in its riser and its downcomer.

[0037] The process of the present disclosure is carried out in the presence of a polymerization catalyst. Suitable polymerization catalysts are all customary olefin polymerization catalysts. That means the polymerization can be carried out using Phillips catalysts based on chromium oxide, using Ziegler- or Ziegler-Natta-catalysts, or using single-site catalysts. For the purposes of the present disclosure, single-site catalysts are catalysts based on chemically uniform transition metal coordination compounds.

[0038] Furthermore, it is also possible to use mixtures of two or more of these catalysts for the polymerization of olefins. Such mixed catalysts are often designated as hybrid catalysts. The preparation and use of these catalysts for olefin polymerization are generally known.Cyclone

[0039] The cyclone (5) and (6) has suitable design and configuration adapted to efficiently separate polyolefin particles and hydrocarbon gas that is discharged from the olefin polymerization unit (1). The cyclones used in the present system are configured to receive the polymer rich stream (7) and (8).

[0040] The cyclone (5) and cyclone (6) may comprise the top section (5b), (6b), a cylindrical section (5c), (6c), a conical section (5d), (6d) and the bottom section (5a), (6a); wherein the cyclone inlet (9), (10) are proximal to the top section (5b), (6b) and distal to the bottom section (5a), (6a); wherein the top section (5b), (6b), the cylindrical section (5c), (6c), the conical sectionPOLY0077-WO-ORD9(5d), (6d) and the bottom section (5a), (6a) are each in fluid communication and vertically co-axial with each other.

[0041] The top section top section (5b), (6b) may comprise an outlet, which discharges the stream (14), (15) at a cyclone outlet velocity ranging from > 40.0 m / s and < 60.0 m / s.

[0042] Preferably, the bottom section (5a), (6a) of the cyclone (5) and cyclone (6) comprises a dipleg (5e), (6e), a loop seal (51), (61) positioned downstream to the dipleg (5e), (6e) and an angular conduit (5g), (6g) positioned downstream to the loop seal (51), (61), wherein the conical section (5d), (6d), the dipleg (5e),(6e) and the loop seal (51), (61) and the angular conduit (5g), (6g) are each in fluid communication with each other.

[0043] Referring to FIG.4, each of the cyclone (5), (6) comprises the cyclone inlet (9), (10) adapted to receive the streams (7), (8). The cyclone inlet has a suitable height and width to receive the streams (7) or (8). For example, the cyclone inlet height (a) may be > 5.0 inch and < 40.0 inch, preferably > 10.0 inch and < 35.0 inch, preferably > 18.0 inch and < 22.0 inch. The width (b) of the cyclone inlet may be > 2.0 inch and < 15.0 inch, preferably > 3.0 inch and < 12.0 inch, preferably > 4.0 inch and < 7.0 inch.

[0044] Preferably, the height of the cylindrical section (Hb) of the cyclone is > 75.0 inch and < 150 inch, preferably > 80.0 inch and < 140.0 inch.

[0045] Preferably, the diameter of the cylindrical section of the cyclone (Db) is > 15.0 inch and < 50.0 inch, preferably > 20.0 inch and < 45.0 inch.

[0046] Preferably, the height of the vortex finder (S) of the cyclone is > 14.0 inch and < 35.0 inch, preferably > 18.0 inch and < 30.0 inch. Each of the cyclone (5) and (6) has a conical section (5d), (6d). The conical section of the cyclone has a conical height (He) of > 25.0 inch and< 70.0 inch, preferably > 30.0 inch and < 60.0 inch.

[0047] Preferably, each of the cyclone (5), (6) has a cyclone height (H) of > 90.0 inch and< 170.0 inch, preferably > 105.0 inch and < 160.0 inch.

[0048] For example, each of the cyclone (5) and (6) has: i) a ratio of height of the cylindrical section (Hb) to diameter of the cylindrical section (Db) is in the range of > 2: 1 to < 5: 1; and ii) a ratio of cyclone inlet height (a) to cyclone inlet width (b) in the range of > 2: 1 and < 3:1, where cyclone inlet height is the height of the cyclone inlet (9), (10) and cyclone inlet width is the width of the cyclone inlet (9), (10).POLY0077-WO-ORD10

[0049] The conical section (5d), (6d), is in fluid communication with the dipleg. The dipleg may have a diameter of > 12.0 inch and < 25.0 inch, preferably > 14.0 inch and < 20.0 inch.

[0050] The bottom section (5a), (6a) of the cyclone (5) and cyclone (6) comprises a dipleg (5e), (6e), a loop seal (5f), (6f) positioned downstream to the dipleg (5e), (6e) and an angular conduit (5g), (6g) positioned downstream to the loop seal (5f), (6f), wherein the conical section (5d), (6d), the dipleg (5e),(6e) and the loop seal (5f), (6f) and the angular conduit (5g), (6g) are each in fluid communication with each other.

[0051] The dipleg (5e), (6e) of each of the cyclone (5), (6) is connected to and in fluid communication to the loop seal (5f), (6f), such that material flowing downwards through cyclone , exits cyclone through the dipleg and flows into loop-seal. In certain aspects, the dipleg and loopseal can be adapted to receive aeration gas.

[0052] The angular conduit (5g), (6g) comprises a pipe slanted at an angle in a range of 25 to 60 degrees of the horizontal axis. The dipleg (5e), (6e), loop seal (5f), (61) and angular conduit (5g), (6g) are comprised of pipes that may have cross sectional area selected from circular, rectangular, triangular, oblong, and the like.

[0053] The bottom section (5a), (6a) of the cyclone (5) and cyclone (6) is in fluid communication with the product purge bin (13) while the top section (5b), (6b) is in fluid communication with product receiving unit (16).Product Receiving Unit

[0054] The stream (14), (15) are conveyed to the product receiving unit (16). The stream (14), (15) comprises > 0.15 wt.% and < 0.5 wt.% of the polyolefin particles present in the polymer stream (4) and > 99.5 wt.% and < 99.85 wt.%, of the hydrocarbon gas present in the polymer stream (4). Each of the streams (14) and (15) has a particle size distribution (d99) of > 8.0 pm and < 20.0 pm.

[0055] The product receiving unit (16) comprises a blowback unit, a rotary feeder system, mechanical delumper system, and a filtration chamber (23) containing particulate filters, wherein filtration chamber (23) has a cylindrical configuration having an inner diameter of > 0.5 m and < 3.5 m, preferably > 0.5 m and < 3.0 m; wherein the blowback unit is configured to inject nitrogen into the filtration chamber (23).POLY0077-WO-ORD11

[0056] The stream (14), (15) may be conveyed to the Product Receiver Unit (16) using a conveying gas. The stream (14), (15) once injected is held in the Product Receiver Unit (16) for a residence time of 2-10 seconds.

[0057] A recycled light gas, such as nitrogen, may be injected from the blowback unit to sweep interstitial hydrocarbons and dissolved hydrocarbons from the polyolefin particles. Nitrogen introduced in the Product Receiving unit (16) assists in conveying the solid particles to the rotary feeder system.

[0058] The rotary feeder discharges the stream (17) via the mechanical delumper system (not shown) to the product purge bin (13). The mechanical delumper system is adapted to break the polymeric lump and agglomerates of uneven shape and sizes down to the desired size.

[0059] The mixture of entrained hydrocarbons and lights gas (24) that is separated from the solid polymeric particles, flows through an array of filters in the filtration chamber (23) for the removal of residual entrained solids prior. Subsequently, the stream (24) is fed to a vent recovery system. The stream (24) is substantially free of solid particles. The stream (24) may have a particle size distribution (d99) of > 0.1 pm and < 0.5 pm.Product Purge Bin

[0060] The product purge bin (13) is configured to receive the streams (11), (12) and (17). Once injected inside the product purge bin (13), the stream(s) is held for a residence time of 2-3 hours, sufficient to remove the interstitial hydrocarbons present in the polyolefin particles to trace levels.

[0061] A steam-in-nitrogen mixture may be introduced at the upper section of the product purge bin unit (13). Such a mixture purges or strips of the dissolved hydrocarbons and neutralizes any catalyst residues that may be present in the streams that are introduced in the unit (13). The stream (18) discharged from the product purge bin unit (13) comprises polyolefin.

[0062] The product purge bin unit (13) may contain an array of filters to further remove entrained solids prior to obtaining the stream (18).

[0063] Accordingly, the present invention now enables a skilled person to design and use system with two independent cyclones coupled to Product Receiving unit that has reduced number of particulate filters and reduced size as compared to a conventional Product Receiving unit. A skilled person knows from common general knowledge that a conventional Product Receiving unitPOLY0077-WO-ORD12 for a polyolefin production system has typically a 150 to 200 particulate filters. However, the skilled person using the current system in accordance with the present invention may use less than 100 particulate filters preferably less than 50 particulate filters, preferably less than 25 particulate filters and greater than 10 particulate filters. Further, the Product Receiving unit with reduced size enables material cost saving and better operating efficiency.

Claims

POLY0077-WO-ORD13CLAIMSWhat is claimed is:

1. A process for producing polyolefin comprising the steps of: i) obtaining a polymer stream (4) from an olefin polymerization unit (1) comprising a gas phase reactor (la) and a product discharge section (lb); ii) supplying at least a portion of the polymer stream (4) into at least two cyclones (5) and (6) independently such that the stream (7) is introduced into the cyclone (5) through the cyclone inlet (9) and the stream (8) is introduced into the cyclone (6) through the cyclone inlet (10); iii) recovering a stream (11) from the bottom section (5a) of the cyclone (5) and recovering a stream (12) from the bottom section (6a) of the cyclone (6); iv) supplying each of the stream (11) and stream (12) into a product purge bin unit (13); v) recovering a stream (14) from the top section (5b) of the cyclone (5) and recovering a stream (15) from the top section (6b) of cyclone (6); vi) introducing at least a portion of each of the streams (14) and (15) into a product receiving unit (16) and subsequently recovering a stream (17); vii) supplying at least a portion of the stream (17) into the product purge bin unit (13); and viii) subjecting each of the streams (11), (12) and (17) introduced in the product purge bin unit (13) to conditions of stripping to obtain a product stream (18) comprising the polyolefin; preferably wherein the number of cyclones is two and the polymer stream (4) is supplied into the two cyclones (5) and (6) independently such that the stream (7) is introduced into the cyclone (5) through the cyclone inlet (9) and the stream (8) is introduced into the cyclone (6) through the cyclone inlet (10).

2. The process of claim 1, wherein the polymer stream (4) comprises a mixture of polyolefin particles and hydrocarbon gas, wherein the polyolefin particles has a particle size distribution (d30) ranging from > 200 and < 300 pm and a particle size distribution (d99) from > 500 and < 1500 pm, wherein particle size distribution is determined using dynamic light scattering; and wherein the hydrocarbon gas has a density between >1.0 and < 5.0 kg / m3.POLY0077-WO-ORD3. The process according to any one of claims 1-2, wherein each of the streams (14) and (15) comprises > 0.15 wt.% and < 0.5 wt.% of the polyolefin particles present in the polymer stream (4) and > 99.5 wt.% and < 99.85 wt.% of the hydrocarbon gas present in the polymer stream (4); and wherein the each of the streams (14) and (15) has a particle size distribution (d99) of > 8.0 pm and < 20.0 pm.

4. The process according to any one of claims 1-3, wherein the stream (7) and the stream (8) are each introduced into the cyclone at a cyclone inlet velocity ranging from > 15.0 m / s and < 25.0 m / s; and / or wherein the streams (14) and (15) are each recovered from the top sections of the cyclone (5b), (6b) at a cyclone outlet velocity ranging from > 40.0 m / s and < 60.0 m / s.

5. The process according to any one of claims 1-4, wherein the streams (11) and (12) comprises > 99.5 wt.% and < 99.85 wt.% of the polyolefin particles present in the polymer stream (4) and > 0.15 wt.% and < 0.5 wt.% of the hydrocarbon gas present in the polymer stream (4); and wherein the each of the streams (11) and (12) has a particle size distribution (d99) of > 500 and < 1500 pm.

6. The process according to any one of claims 1-5, wherein the cyclone (5) and (6) are operating under the conditions of:(a) an average residence time for stream (7) and stream (8) ranging from > 5.0 and < 35.0 seconds;(b) a cyclone inlet temperature of > 50 °C and < 60 °C;(c) a cyclone inlet pressure of > 60 and < 100 kPag; and(d) an average volumetric gas flow rate of > 80 and < 240 m3 / min; and(e) a cyclone inlet solid loading of > 6.0 and < 43.0 kg of solid polyolefin parti cles / m3of hydrocarbon gas.

7. The process according to any one of claims 1-6, wherein the polyolefin is polypropylene, polyethylene or copolymers thereof, preferably wherein the polyolefin is polypropylenePOLY0077-WO-ORD15 having a particle density ranging from > 500.0 and < 700.0 kg / m3, determined in accordance with ASTM DI 895- 17.

8. A system for producing polyolefin according to the process of claims 1-7, wherein the system comprises: a. the olefin polymerization unit (1) positioned upstream and operably connected to at least the two cyclones (5) and (6) such that the cyclone inlet (9) is adapted to receive stream (7) and cyclone inlet (10) is adapted to receive stream (8); b. the product receiving unit (16) positioned downstream to each of the cyclones (5) and (6); wherein the top section (5b) of cyclone (5) is operably connected to the product receiving unit (16) and the top section (6b) of cyclone (6) is operably connected to the product receiving unit (16); and c. the product purge bin unit (13) positioned downstream to each of the cyclone (5), cyclone (6) and to the product receiving unit (16), wherein the bottom section (5a) of the cyclone (5) is operably connected to the product purge bin system (13) and the bottom section (6a) of the cyclone (6) is operably connected to the product purge bin system (13). preferably the olefin polymerization unit (1) comprises a gas phase reactor (la).

9. The system of claim 8, wherein the cyclone (5) and cyclone (6) comprises the top section (5b), (6b), a cylindrical section (5c), (6c), a conical section (5d), (6d) and the bottom section (5a), (6a); wherein the cyclone inlet (9), (10) are proximal to the top section (5b), (6b) and distal to the bottom section (5a), (6a); wherein the top section (5b), (6b), the cylindrical section (5c), (6c), the conical section (5d), (6d) and the bottom section (5a), (6a) are each in fluid communication and vertically co-axial with each other.

10. The system according to claim 8-9, wherein the bottom section (5a), (6a) of the cyclone (5) and cyclone (6) comprises a dipleg (5e), (6e), a loop seal (51), (61) positioned downstream to the dipleg (5e), (6e) and an angular conduit (5g), (6g) positioned downstream to the loop seal (51), (61), wherein the conical section (5d), (6d), the dipleg (5e),(6e) and the loop seal (51), (61) and the angular conduit (5g), (6g) are each in fluid communication with each other.POLY0077-WO-ORD1611. The system according to any one of claims 8-10, wherein each of cyclones (5) and (6) are in fluid communication with a product discharge unit (lb) of the olefin polymerization unit (1) such that the product discharge unit (lb) of the olefin polymerization (1) is positioned upstream to each of the cyclones (5) and (6) and downstream to the gas phase reactor (la).

12. The system according to any one of claims 8-11, wherein each of the cyclone (5) and (6) has: i) a ratio of height of the cylindrical section (Hb) to diameter of the cylindrical section (Db) is in the range of > 2: 1 to < 5: 1; and ii) a ratio of cyclone inlet height (a) to cyclone inlet width (b) in the range of > 2: 1 and < 3: 1, where cyclone inlet height is the height of the cyclone inlet (9), (10) and cyclone inlet width is the width of the cyclone inlet (9), (10).

13. The system according to any one of claims 8-12, wherein the product receiving unit (16) comprises blowback unit (24), rotary feeder system, mechanical delumper system, a filtration chamber (23) containing particulate filters, wherein filtration chamber (23) has a cylindrical configuration having an inner diameter of > 0.5 m and < 3.0 m and wherein the blowback unit (24) is configured to inject nitrogen into the filtration chamber (23).

14. The system according to any one of claims 10-13, wherein the filtration chamber (23) of the product receiving unit (16) has less than 100 particulate filters, preferably less than 50 particulate filters, preferably less than 25 particulate filters and greater than 10 particulate filters.

15. Use of the system according to claims 8-14 for improving polyolefin particle-hydrocarbon gas separation in a polyolefin production process while reducing the number of particulate filters in product receiving unit by at least 50%, preferably up to 90%.

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