A cyclone separator system and method that maintains high efficiency at low process gas rates

Abstract

The present application relates to the technical field of cyclone separator, and provides a cyclone separator system and method for keeping high efficiency at low processing air volume, which comprises an air inlet pipeline, a branch pipeline, an air volume adjusting valve, an air volume adjusting controller, a separator pressure drop monitor, a cyclone separator, an exhaust pipeline and a dust unloading valve. The separator pressure drop monitor is connected with the air volume adjusting controller through a signal line, and the air volume adjusting controller is connected with the air volume adjusting valve through a signal line. During operation, the air volume adjusting controller drives the air volume adjusting valve to work according to the working pressure drop signal of the cyclone separator monitored by the separator pressure drop monitor in real time, controls the air volume supplemented to the cyclone separator by the branch pipeline, and keeps the air volume through the cyclone separator stable. The present application solves the problem of low separation efficiency of the cyclone separator in the prior art at low processing air volume, and has the advantages of no manual operation, simplicity, practicality, low investment, good effect and suitability for the design and modification of the cyclone separator system.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of cyclone separator technology, and in particular to a cyclone separator system and method for maintaining high efficiency of a cyclone separator at low gas flow rates. BACKGROUND

[0002] A cyclone separator is a commonly used device for non-homogeneous separation of gas-solid or gas-liquid systems and gas-liquid-solid systems. The working principle of the cyclone separator is that the tangential entry of gas flow causes rotational motion, which makes solid particles (or liquid droplets) under the action of a larger centrifugal force fly to the wall of the separator, thereby separating from the gas flow, and then falling along the wall of the separator to the dust discharge port at the lower part of the cone, and leaving the separator; the relatively clean gas flow rotates upward, and finally is discharged from the central exhaust pipe at the top of the separator. The cyclone separator has the advantages of simple structure, low cost, high efficiency, moderate pressure drop, and can be used in harsh process environments such as high temperature, high pressure, high particle concentration, high wear, and high corrosion, and is easy to operate and maintain, and has been widely used in process industry, environmental protection and other fields. However, the cyclone separator also has some disadvantages, for example, poor adaptability to operating gas flow fluctuation conditions, large change in separation efficiency with operating gas flow, and significant decrease in separation efficiency at low gas flow. Because, as the processing gas flow of the cyclone separator increases from zero, its separation efficiency first increases with the increase of the gas flow; when it reaches a certain gas flow (referred to as the maximum efficiency gas flow, Q maxe ), the efficiency reaches the maximum, and then the gas flow increases, the efficiency decreases; the pressure drop of the cyclone separator increases with the increase of the processing gas flow, as shown in Figure 1 . That is, the cyclone separator can only be operated at a gas flow slightly lower than its maximum efficiency gas flow to achieve the best energy-saving and emission-reducing effect. At low gas flow (lower than the maximum efficiency processing gas flow), although the pressure drop of the cyclone separator is low, the efficiency is also low, the particle loss is large, and the economic benefit is poor; if the processing gas flow is greater than the maximum efficiency processing gas flow, not only the efficiency is low, but also the pressure drop is high, therefore, at any time, the cyclone separator should avoid operating at a processing gas flow greater than the maximum efficiency processing gas flow.

[0003] For the actual production process operation fluctuation, device start-stop and other causes of cyclone separator processing gas fluctuation, resulting in cyclone separator separation efficiency instability, efficiency reduction, particle loss increase problem, the skilled person in the art has put forward some solutions. For example, patent 1 (patent application number 201721819403.4) discloses a "self-adjusting cyclone separator", when the dust sensor installed at the exhaust port of the cyclone separator monitors that the dust concentration at the exhaust port is high, the concentration signal is converted into the signal of the stepping motor rotation through the converter, and the stepping motor is used to control the rotation of the adjusting plate installed at the air inlet of the cyclone separator, so that the air hole of the air inlet pipe is expanded or reduced, to control the air inlet amount, to solve the problem that when the air pressure at the air inlet pipe is too large, there are more impurities in the air discharged from the air outlet pipe, and manual operation is not required, which is convenient to use. For example, patent 2 (patent application number 201611077274.6) discloses a "cyclone separator and method with automatic adjustment of filtering effect", that is, a photoelectric sensor is installed at the exhaust port of the cyclone separator, the photoelectric sensor is used to monitor the light transmittance (i.e. particle concentration) of the exhaust gas at the exhaust port, and the signal is transmitted to the automatic control unit for processing, to drive the flow adjusting cam to rotate the flow adjusting plate to adjust the flow rate of the dust-containing gas in the air inlet pipe, so as to keep the inlet air speed stable; at the same time, the adjustment gear is driven to adjust the insertion depth of the central inner cylinder in the separator, so as to realize real-time automatic control of the filtering effect (i.e. separation efficiency) of the cyclone separator. However, these schemes have some defects: first, they are only suitable for cases where the gas amount is too large or the air pressure is too large, and cannot solve the problem of cyclone separator efficiency reduction caused by low gas amount, such as when the cyclone separator processing gas amount is much lower than the design (predetermined) gas amount, when the process gas amount of the device increases from zero to normal during device startup, and when the process gas amount gradually decreases to zero during shutdown; second, the monitoring system is complex, the measurement accuracy and accuracy of the dust sensor and the photoelectric sensor are not high, and the price is relatively high; third, the air inlet adjusting plate is used to control the air inlet amount when the air pressure at the air inlet pipe is too large, or the flow adjusting plate is used to control the air flow rate, which uses the throttling principle, which will cause throttling loss and additional energy consumption; moreover, the gas amount processed by the cyclone separator is usually determined according to the production process requirements and cannot be changed or limited at will, and increasing the outflow resistance of the gas flow may affect the production process. Therefore, the practicability of these schemes in the prior art is poor, and further technical innovation is needed. SUMMARY

[0004] The present application provides a cyclone separator system and method for automatically maintaining high efficiency of a cyclone separator under low processing gas conditions, which is simple and easy to implement.

[0005] In order to achieve the above-mentioned purpose, the present application adopts the following technical methods and systems:

[0006] A method for automatically maintaining a stable and high-efficiency cyclone separator at low gas throughput, characterized in that: (1) the cyclone separator operates at its maximum efficiency gas throughput Q maxe The design involves taking the maximum value Q of the fluctuating gas volume of the production unit involved. 1max ≤Q maxe And Q 1max ≈Q maxe According to the gas volume Q 1max Design this cyclone separator; (2) The cyclone separator is equipped with pressure monitors at both the dust-laden gas inlet and the exhaust port to monitor the pressure drop PD of the cyclone separator in real time; branch pipelines and gas flow regulating valves and gas flow regulating controllers are installed on the inlet pipeline of the cyclone separator.

[0007] Because, according to the appendix Figure 1 The cyclone separator operation-performance characteristic curves shown demonstrate that, given a fixed geometric dimension for each part of the cyclone separator, the relationship between its pressure drop (PD) and the gas throughput (Q) is definite (i.e., the pressure drop of the cyclone separator...). Where ξ and ρ g Q, A i These are the resistance coefficient of the cyclone separator, the density of the inlet dust-laden gas, the processing capacity of the cyclone separator, and the inlet area, respectively. Therefore, by adjusting the branch gas volume Q2 in real time based on the real-time monitored pressure drop PD information of the cyclone separator, the processing capacity Q of the cyclone separator can be automatically adjusted in real time, or the Q value can be kept constant (because Q≡Q1+Q2 is always true), regardless of the degree of fluctuation in the process gas volume Q1 generated by the production unit.

[0008] During operation, when the process gas volume Q1 generated by the production unit and entering the cyclone separator fluctuates significantly, or when the unit starts or stops (Q1 gradually increases from 0 during startup and gradually decreases to 0 during shutdown), the pressure drop PD signal of the cyclone separator, which is monitored in real time by the pressure monitor, is input to the gas volume regulating controller. This generates a working signal to replenish the gas in the drive branch pipeline, increasing or decreasing the gas intake volume Q2 of the branch. This allows the total processed gas volume Q entering the cyclone separator to be automatically maintained at the set operating gas volume Q. lmax This automatically maintains the separation efficiency of the cyclone separator at a stable level, ensuring effective separation. If the gas flow rate Q entering the cyclone separator is maintained close to the separator's maximum efficiency flow rate Q... maxe Even if the amount of process gas Q1 produced by the production unit is very low, the efficiency of the cyclone separator can be automatically adjusted to the maximum efficiency level to achieve the best separation effect.

[0009] The application also provides a cyclone separator system which can automatically maintain high efficiency under low processing gas volume, characterized in that the cyclone separator system comprises an air inlet pipeline, a branch pipeline, a gas volume adjusting valve, a cyclone separator, a dust unloading valve, an exhaust pipe, a separator pressure monitor and a gas volume adjusting controller.

[0010] The branch pipeline (2) has at least one opening or is a pipe opening or a device interface with at least one opening.

[0011] Further, the pressure monitors at the air inlets and the exhaust pipes are preferably electronic pressure gauges, differential pressure sensors or pressure transmitters, i.e. pressure monitors of existing mature technology.

[0012] Further, the gas volume adjusting valve is preferably an electrically or pneumatically operated adjusting valve, i.e. an adjusting valve of existing mature technology.

[0013] Further, the gas volume adjusting controller is composed of a signal processor, a stepping motor, a power supply circuit and a signal circuit.

[0014] Compared with the prior art, the application has the following beneficial effects: according to the operating-performance relationship characteristics of the cyclone separator, the gas volume introduced through the branch (air supplementing) pipeline is adjusted in real time based on the differential pressure (or pressure drop) information of the air inlets and the exhaust pipe of the cyclone separator, so as to suppress the fluctuation of the process gas volume input into the cyclone separator (including start-up and shutdown conditions), and maintain the total gas volume entering the cyclone separator at a set gas volume or a level close to the maximum efficiency gas volume of the cyclone separator, thereby ensuring that the cyclone separator reaches the best separation efficiency, and particularly, the cyclone separator can work near the maximum efficiency point even under low processing gas volume. The application is simple and practical, has low investment, does not require manual operation, has good effects and is easy to popularize. BRIEF DESCRIPTION OF DRAWINGS

[0015] Figure 1 It is a graph of the operating-performance relationship characteristics of the cyclone separator;

[0016] Figure 2 It is an embodiment of the cyclone separator system of the application;

[0017] Figure 3 It is a cold model test effect according to the scheme shown in Figure 2

[0018] ​Figure legend: 1 - inlet line, 2 - bypass line (air make-up line), 3 - flow rate regulating valve, 4 - flow rate regulating controller, 5 - separator pressure drop monitor, 6 - exhaust line, 7 - cyclone separator, 8 - dust valve, Q1 - process gas rate generated by production unit that needs to be treated by cyclone separator, Q2 - air make-up rate, Q - total gas rate through cyclone separator. DETAILED DESCRIPTION

[0019] To more clearly illustrate the embodiments of the present application, a brief description is given below with reference made to the accompanying drawings. Obviously, the drawings in the following description are only some typical embodiments of the present application, and not all the embodiments. Other drawings can be obtained by those skilled in the art without any creative effort based on these drawings.

[0020] A cyclone separator system and method that automatically maintains high efficiency at low process gas rates.

[0021] One embodiment of the present application is shown in Figure 2 , which includes: an inlet line 1, a bypass line (or air make-up line) 2, a flow rate regulating valve 3, a flow rate regulating controller 4, a separator pressure drop monitor 5, an exhaust line 6, a cyclone separator 7, and a dust valve 8.

[0022] When the system is in operation, dust (or liquid droplet) containing gas Q1 generated by a production unit enters the cyclone separator 7 through the inlet line 1 for gas-solid (or gas-liquid) separation, and the separated dust (or liquid droplet) is discharged through the dust valve 8. Clean gas is discharged from the exhaust line 6 at the top of the cyclone separator 7. The separator pressure drop monitor 5 monitors the pressure drop of the cyclone separator 7 in real time and sends a signal to the flow rate regulating controller 4. In Figure 2 the embodiment of the present application, the flow rate regulating controller 4 controls the operation of the flow rate regulating valve 3 according to the operating pressure drop PD of the cyclone separator 7 monitored by the separator pressure drop monitor 5. When Q1 is lower than the design gas rate, the flow rate regulating valve 3 is opened to allow air make-up gas Q2 to enter the cyclone separator 7 from the air make-up line, so that the process gas rate Q (Q = Q1 + Q2) of the cyclone separator 7 is maintained at a set value. Figure 3 A cyclone separator with a diameter of 300 mm is used to simulate Figure 2 the embodiment of the present application, and a test is conducted using 800 mesh talc powder. The measured effect diagram of the inlet air make-up of the cyclone separator is shown in Figure 3 It can be seen from the diagram that the maximum efficiency gas rate of the model cyclone separator is about 700 m3 / h, at which the separation efficiency is the highest, about 93%. When the process gas rate is lower or higher than 700 m3 / h, the separation efficiency is reduced. When the process gas rate is greater than 700 m3 / h, the separation efficiency decreases rapidly. The present application Figure 2The air supplementing scheme can maintain the separation efficiency near the maximum efficiency of 93%, and the stable efficiency effect is very significant.

[0023] The above is only one embodiment of the present application, and does not limit the protection scope of the present application, and any equivalent structure or equivalent process transformation using the content of the present application specification, or direct or indirect application in other related technical fields, are also included in the patent protection scope of the present application.

Claims

1. A cyclone separator system that maintains high efficiency at low process gas rates, comprising an inlet gas line (1), a bypass line (2), a gas rate regulating valve (3), a gas rate regulating controller (4), a separator pressure drop monitor (5), an exhaust line (6), a cyclone separator (7), a dust unloading valve (8), characterized in that, The inlet pipeline (1) is connected with the cyclone separator (7) on one side of the cyclone separator (7), the inlet pipeline (1) is provided with a branch pipeline (2), the branch pipeline (2) is provided with a gas volume regulating valve (3), the gas volume regulating valve (3) is connected with a gas volume regulating controller (4), the gas volume regulating controller (4) is connected with a separator pressure drop monitor (5), the pressure tapping of the separator pressure drop monitor (5) is respectively arranged at the inlet pipe and the exhaust pipe of the cyclone separator (7), the exhaust pipeline (6) is connected with the top of the cylinder of the cyclone separator (7), and the ash valve (8) is connected with the bottom of the cone of the cyclone separator (7); The signal output end of the separator pressure drop monitor (5) is connected with the signal input end of the gas volume regulating controller (4) through a signal line, and the signal output end of the gas volume regulating controller (4) is connected with the signal input end of the gas volume regulating valve (3) through a signal line; The cyclone separator (7) is designed according to the maximum efficiency gas volume Qmaxe, that is, the maximum value Q1max of the fluctuation gas volume of the production device involved is Q1max≤Qmaxe and Q1max≈Qmaxe; When the process gas volume Q1 generated by the production device and entering the cyclone separator (7) fluctuates or the device is started or stopped, the working pressure drop of the cyclone separator (7) is measured online and in real time by the separator pressure drop monitor (5), and the measured real-time pressure drop signal is transmitted to the gas volume regulating controller (4) for processing, the output signal of the gas volume regulating controller drives the gas volume regulating valve (3) to work, the gas volume supplemented into the cyclone separator (7) from the branch pipeline (2) is regulated, so that the gas volume passing through the cyclone separator (7) is automatically maintained at a set value, and the separation efficiency of the cyclone separator (7) is kept stable and high.

2. A cyclonic separator system that maintains high efficiency at low process gas rates according to claim 1, wherein, The branch pipeline (2) has at least one opening.

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