Polyolefin pellet hydraulic conveying device

Abstract

The application discloses a kind of polyolefin granular material hydraulic conveying devices, including water tank, agitator, separating screen, first storage hopper and second storage hopper;Wherein, the discharge port of first storage hopper and second storage hopper is communicated with the feed inlet of mixing tank by pipeline;The discharge port at the bottom of mixing tank is communicated with separating screen by conveying pipeline equipped with granular conveying pump, and the liquid phase outlet at the bottom of separating screen is communicated with water tank by backwater pipeline, and the liquid outlet at the bottom of water tank is communicated with mixing tank by pipeline equipped with clean water pump;The solid phase outlet of separating screen is communicated with the feed inlet of first storage hopper and second storage hopper by pipeline.Compared with traditional pneumatic conveying technology, the application has significant advantages in long-distance large-capacity conveying, reducing energy consumption, reducing material consumption, safety and environmental protection, reducing construction and operation cost, etc.Due to low conveying speed, it has unique advantages in solving the conveying of fragile and strongly abrasive materials.

Description

Technical Field

[0001] This invention relates to the field of chemical equipment technology, and in particular to a hydraulic conveying device for polyolefin granules. Background Technology

[0002] In existing chemical plants, polyolefin granular materials are typically transported primarily by pneumatic conveying. Pneumatic conveying, also known as airflow conveying, utilizes the energy of airflow to transport granular materials along the airflow direction within a closed pipeline; it is a specific application of fluidization technology. Pneumatic conveying devices have a simple structure, are easy to operate, and can perform horizontal, vertical, or inclined conveying. During the conveying process, physical operations such as heating, cooling, drying, and airflow classification, or certain chemical operations, can be performed simultaneously on the material.

[0003] However, for long-distance (conveying distance greater than 500 meters), high-capacity (conveying capacity greater than 100t / h), or conveying applications where materials are fragile or highly abrasive, pneumatic conveying has disadvantages such as high energy consumption, high material consumption, high dust content in exhaust gas, reduced material quality, and short pipeline life, making it an undesirable conveying method.

[0004] Therefore, providing a technical means suitable for conveying polyolefins over long distances, with high capacity, and where the materials are fragile and highly abrasive is an important research direction. Summary of the Invention

[0005] This invention aims to develop a hydraulic conveying device for polyolefin granular materials, overcome the limitations of pneumatic conveying, and provide a hydraulic conveying process for long-distance, high-capacity applications, solving the difficulties in conveying fragile and highly abrasive materials.

[0006] This invention provides a hydraulic conveying device for polyolefin granules, comprising a water tank, a mixing tank, a separating screen, a first storage hopper, and a second storage hopper; wherein,

[0007] The discharge ports of the first and second storage hoppers are connected to the inlet of the mixing tank via pipes; the discharge port at the bottom of the mixing tank is connected to the separating screen via a conveying pipe equipped with a particle conveying pump; the liquid phase outlet at the bottom of the separating screen is connected to a water tank via a return water pipe; the liquid outlet at the bottom of the water tank is connected to the mixing tank via a pipe equipped with a clean water pump; the solid phase outlet of the separating screen is connected to the inlet of the first and second storage hoppers via pipes.

[0008] Preferably, the metering device for the pipeline between the outlet of the first and second storage hoppers and the mixing tank is a rotary valve.

[0009] Preferably, on the conveying pipeline, a fluid distributor is arranged downstream of the particle conveying pump, and a bypass outlet of the fluid distributor is communicated with the mixing tank through a pipeline.

[0010] Further, a first regulating valve is arranged on the pipeline between the bypass outlet of the fluid distributor and the mixing tank.

[0011] Preferably, on the pipeline between the water tank and the mixing tank, a second regulating valve, a flow transmitter and a temperature transmitter are arranged downstream of the clean water pump.

[0012] Preferably, a liquid level meter is arranged on the mixing tank.

[0013] Preferably, a first sight glass is arranged on the mixing tank.

[0014] Preferably, on the conveying pipeline, a second sight glass is arranged upstream of the particle conveying pump.

[0015] Preferably, a conveying pipeline pressure transmitter is arranged on the conveying pipeline.

[0016] Preferably, the particle conveying pump is an open rotor centrifugal pump or a semi-open rotor centrifugal pump.

[0017] Compared with the prior art, the present application has the following technical effects:

[0018] Compared with the conventional pneumatic conveying technology, the present application has significant advantages in long-distance large-capacity conveying, reducing energy consumption, reducing material consumption, safety and environmental protection, reducing construction and operation costs, etc. Due to the low conveying speed, it has unique advantages in solving the conveying of fragile and strongly abrasive materials.

[0019] Through industrial-scale test device experiments, it can realize continuous and stable conveying of slurry with a solid-liquid ratio of more than 60% in volume concentration, i.e. the amount of material conveyed per unit of water is increased by about 100%, greatly improving the conveying efficiency. BRIEF DESCRIPTION OF DRAWINGS

[0020] Figure 1 Fig. 1 is a structural schematic diagram of a polyolefin particle hydraulic conveying device in the present application;

[0021] The marks in the figure represent the following:

[0022] 1 - water tank, 2 - fresh water pump, 3 - agitator, 4 - mixing tank, 5 - particle conveying pump, 6 - separation sieve, 7 - first storage hopper, 8 - second storage hopper, 9 - rotary valve, 10 - fluid distributor, 11 - conveying pipeline, 12 - backwater pipeline, 13 - pressure transmitter, 14 - first regulating valve, 15 - second regulating valve, 16 - liquid level gauge, 17 - first sight glass, 18 - second sight glass, 19 - ball valve, 20 - flow transmitter, 21 - temperature transmitter. DETAILED DESCRIPTION

[0023] The application will be described in detail and specifically below by means of specific examples, so as to make better understanding of the application, but the following examples do not limit the scope of the application.

[0024] Example 1

[0025] Referring to Figure 1 The application provides a polyolefin particle hydraulic conveying device, which comprises a water tank 1, a mixing tank 4, a separation sieve 6, a first storage hopper 7 and a second storage hopper 8.

[0026] Specifically, the discharge outlets of the first storage hopper 7 and the second storage hopper 8 are communicated with the feeding inlet of the mixing tank 4 through a pipeline provided with a rotary valve 9. The discharge outlet at the bottom of the mixing tank 4 is communicated with the separation sieve 6 through a conveying pipeline 11 provided with a particle conveying pump 5. The liquid phase outlet at the bottom of the separation sieve 6 is communicated with the water tank 1 through a backwater pipeline 12, and the liquid outlet at the bottom of the water tank 1 is communicated with the mixing tank 4 through a pipeline provided with a fresh water pump 2. The solid phase outlet of the separation sieve 6 is communicated with the feeding inlets of the first storage hopper 7 and the second storage hopper 8 through pipelines.

[0027] The material is stored in the first storage hopper 7 and the second storage hopper 8 (alternately stored), added to the mixing tank 4 through the rotary valve 9, fully stirred and mixed with the backflow water from the fresh water pump 2 in the mixing tank 4 through the agitator 3, sucked into the tank bottom and enters the particle conveying pump 5 under the action of the vortex flow field, conveyed to the upper separation sieve 6 through the conveying pipeline 11 under the action of the water flow, and the solid-liquid separation is realized through the sieve screen, the particle material falls into the first storage hopper 7 and the second storage hopper 8, and the separated water returns to the water tank 1 through the backwater pipeline 12 for recycling.

[0028] In a preferred embodiment, a fluid distributor 10 is arranged downstream of the particle conveying pump 5 on the conveying pipeline 11, and the bypass outlet of the fluid distributor 10 is communicated with the mixing tank 4 through a pipeline. The mixture discharged from the tank bottom of the particle conveying pump 5 comprises particles and water, and the fluid distributor 10 returns part of the water to the mixing tank 4.

[0029] Furthermore, a first regulating valve 14 is provided on the pipeline between the bypass outlet of the fluid distributor 10 and the mixing tank 4. Downstream of the fluid distributor 10 are a flow transmitter 20, a temperature transmitter 21, and a pressure transmitter 13. Based on the test-related data collected by the flow transmitter 20, temperature transmitter 21, and pressure transmitter 13, the pressure drop required for regression analysis is used to control the opening degree of the first regulating valve 14 and the rotational speed of the particle conveying pump 5.

[0030] In one specific embodiment, a second regulating valve 15, a flow transmitter 20, a temperature transmitter 21, and a pressure transmitter 13 are provided downstream of the water pump 2 on the pipeline between the water tank 1 and the mixing tank 4. A level gauge 16 is provided on the mixing tank 4. The opening degree of the regulating valve 15 is controlled according to the level gauge 16 to maintain the liquid level balance in the mixing tank 4 and achieve flow control.

[0031] In a preferred embodiment, the mixing tank 4 is provided with a first sight glass 17, and a second sight glass 18 is provided upstream of the particle conveying pump 5 on the conveying pipeline 11. The first sight glass 17 and the second sight glass 18 can be used to observe the flow state of the material in the water.

[0032] In a preferred embodiment, the particle conveying pump 5 is an open rotor centrifugal pump or a semi-open rotor centrifugal pump.

[0033] In a preferred embodiment, the separating screen 6 is designed with an adjustable tilt angle, which can be adjusted between approximately 25° and 55° to facilitate conveying experiments.

[0034] In a preferred embodiment, the rotary valve 9 adopts a high-pressure closed rotor design with variable frequency speed regulation, which can continuously measure the feeding capacity and adjust the feeding amount.

[0035] In a preferred embodiment, the conveying pipeline 11 is equipped with a pressure transmitter 13, a flow transmitter 20, and a temperature transmitter 21 to collect test-related data for analysis of the pressure drop required for regression calculation.

[0036] Example 2

[0037] See Figure 1 As shown, a hydraulic conveying test device for polyolefin granules is provided based on Example 1. The difference from Example 1 is that the conveying pipeline 11 is provided with three branches with different conveying distances of 300 meters, 500 meters and 1000 meters. The conveying direction is switched by a manual ball valve 19. Pressure transmitters 13 are provided on the three branches. The separating screen 6 adopts an adjustable tilt angle design. The tilt angle can be adjusted between about 25° and 55° to facilitate conveying experiments.

[0038] Example 3

[0039] The present embodiment provides a kind of polyolefin granular material hydraulic conveying test method, using the test device in embodiment 2.

[0040] Test material is stored in the first storage hopper 7 and the second storage hopper 8, is alternately stored, is added to mixing tank 4 by rotary valve 9, is fully stirred and mixed in tank with backflow water from water pump 2 and fluid distributor 10 by stirrer 3, is sucked into the bottom of tank and enters granular conveying pump 5 under the action of vortex flow field, is conveyed to the upper separation screen 6 by conveying pipeline 11 under the action of water flow, realizes solid-liquid separation through screen, and granular material falls into the first storage hopper 7 and the second storage hopper 8, and the water after separation returns to water tank 1 through backwater pipeline 12 for recycling.

[0041] During the test, the following adjustments and measurements are made:

[0042] (1) The opening of the regulating valve 15 at the outlet of the water pump 2 is controlled according to the liquid level meter 16 to balance the liquid level in the mixing tank 4 and achieve flow control.

[0043] (2) The regulating valve 14 of the granular conveying pump 5 bypass can achieve partial conveying water backflow to adjust the solid-water ratio during conveying.

[0044] (3) The conveying capacity is measured by the rotational speed of the rotary valve 9, and the rotational speed and the corresponding discharge capacity are calibrated by experimental test.

[0045] (4) Both the granular conveying pump 5 and the water pump 2 are controlled by frequency conversion, which can adjust the conveying flow.

[0046] (5) During the test, the flow state of the material in the water can be observed through the first sight glass 17 and the second sight glass 18 installed on the pipeline and the mixing tank.

[0047] (6) The conveying pipeline 11 is divided into three different conveying distance loops of 300 meters, 500 meters and 1000 meters, and the conveying direction is switched by 10 manual ball valves 19. Along the way, flow transmitters 20, pressure transmitters 13 and temperature transmitters 21 are provided to collect relevant test data for analysis of pressure drop required for regression calculation.

[0048] (7) During the test, the conveying distance and the solid conveying amount are first set, the regulating valve opening and the pump rotational speed are adjusted, the liquid flow is from large to small until the phenomenon of nearly blocked pipe appears, the material flow state in the pipeline sight glass is observed, and experimental data such as conveying amount, liquid flow and pipeline pressure drop along the way are collected.

[0049] (8) The granular conveying pump 5 uses a centrifugal pump with open or semi-open rotor, and the design of the centrifugal pump impeller is improved and optimized through CFD simulation calculation to improve the efficiency of the granular conveying pump.

[0050] (9) By designing the water inlet of the mixing tank 4 as a tangential water inlet, and optimizing the blades of the stirrer 3, using multi-layer 45-degree two-oblique stirring blades, and adjusting parameters such as stirring speed and blade spacing, the vortex effect is enhanced, so that the plastic particles are rapidly mixed with water after entering the mixing tank from the upper part, and a vortex is generated to force the downward flow, and then enter the pump suction inlet through the outlet below the tank body, thereby improving the mixing efficiency of stirring and ensuring the discharging efficiency of high-concentration and low-density materials.

[0051] (10) The inclination angle of the separation screen 6 can be adjusted between about 25° and 55°, which facilitates the conveying experiment.

[0052] (11) The rotary valve 9 adopts a high-pressure closed rotor design, and can continuously measure and discharge materials by adjusting the discharge amount.

[0053] The present application determines the process flow, key equipment and control scheme of the water conveying test device through research, and builds a water conveying device with a conveying distance of 1000 meters and a capacity of 25 tons / hour.

[0054] Through the construction of the test device, the capacity, solid-water ratio and conveying pressure of the water conveying are tested, and the solid-liquid two-phase flow model, solid-water ratio determination, pressure loss calculation method and key coefficient regression of the water conveying are studied, and the long-distance, environmentally friendly, safe and economic high-solid-liquid ratio polyolefin particle water conveying complete technology is developed.

[0055] Using the self-developed polyolefin particle material water conveying calculation model, the related calculation software is developed. Through the correction coefficient of the test regression, the database is established, and the water conveying system with different conveying capacity and conveying distance can be calculated to obtain accurate conveying pressure, conveying water quantity, solid-liquid ratio and other design parameters to guide the engineering design.

[0056] Compared with the traditional pneumatic conveying technology, the present application has significant advantages in long-distance and large-capacity conveying, reducing energy consumption, reducing material consumption, safety and environmental protection, and reducing construction and operation costs. Due to the low conveying speed, it has unique advantages in conveying fragile and abrasive materials.

[0057] Through the industrial-scale test device experiment verification, it can realize continuous and stable conveying of slurry with a solid-liquid ratio of more than 60%, that is, the material quantity conveyed per unit water quantity is increased by about one time, which greatly improves the conveying efficiency.

[0058] The above detailed description of the application is only as an example, and the application is not limited to the above described specific embodiments. Any equivalent modifications and substitutions made by those skilled in the art to the application are also within the scope of the application. Therefore, equivalent transformations and modifications made without departing from the spirit and scope of the application should be covered within the scope of the application.

Claims

1. A hydraulic conveying device for polyolefin pellets, characterized in that, The system includes a water tank (1), a stirrer (3), a separating screen (6), a first storage hopper (7), and a second storage hopper (8); wherein the outlets of the first storage hopper (7) and the second storage hopper (8) are connected to the inlet of a mixing tank (4) via pipes; the outlet at the bottom of the mixing tank (4) is connected to the separating screen (6) via a conveying pipe (11) equipped with a particle conveying pump (5); the liquid phase outlet at the bottom of the separating screen (6) is connected to the water tank (1) via a return water pipe (12); the liquid outlet at the bottom of the water tank (1) is connected to the mixing tank (4) via a pipe equipped with a clean water pump (2); and the solid phase outlet of the separating screen (6) is connected to the inlets of the first storage hopper (7) and the second storage hopper (8) via pipes. The mixing tank (4) has a tangential water inlet. The agitator (3) blades are optimized by using multi-layer 45-degree double-inclination agitator blades. Combined with parameters such as stirring speed and blade spacing, the vortex effect is enhanced, so that the plastic particles quickly mix with water after entering the mixing tank (4) from the top and generate a vortex that forces them to flow downwards. They then enter the pump inlet through the outlet below the tank body, improving the mixing efficiency of the agitator and ensuring the feeding efficiency of high-concentration, low-density materials. On the conveying pipeline (11), a fluid distributor (10) is provided downstream of the particle conveying pump (5), and the bypass outlet of the fluid distributor (10) is connected to the mixing tank (4) through a pipeline; A first regulating valve (14) is provided on the pipeline between the bypass outlet of the fluid distributor (10) and the mixing tank (4). The metering device between the outlet of the first storage hopper (7) and the second storage hopper (8) and the mixing tank (4) is a rotary valve (9). On the pipeline between the water tank (1) and the mixing tank (4), a second regulating valve (15), a flow transmitter (20) and a temperature transmitter (21) are provided downstream of the clean water pump (2). The mixing tank (4) is equipped with a level gauge (16). The mixing tank (4) is equipped with a first sight glass (17); A second sight glass (18) is provided upstream of the particle conveying pump (5) on the conveying pipeline (11).

2. The hydraulic conveying device for polyolefin pellets according to claim 1, characterized in that, A pressure transmitter (13) is installed on the conveying pipeline (11).

3. The hydraulic conveying device for polyolefin pellets according to claim 1, characterized in that, The particle conveying pump (5) is an open rotor centrifugal pump or a semi-open rotor centrifugal pump.

Images