Modularized biomass raw material feeding control method

Abstract

The invention discloses a modular biomass raw material feeding control method which is used for controlling raw materials to be conveyed to a gasification furnace unit from a biomass bin unit. Wherein the gasification furnace unit comprises a furnace top hopper and a gasification furnace; the control method comprises the following steps: monitoring in-furnace raw material descending speed corresponding to the gasification furnace in real time; when the descending speed of the raw materials in the furnace is greater than a preset speed value, detecting whether the raw materials exist in a furnace top hopper; if the raw materials exist in the furnace top hopper, it is judged that raw material bridging exists in the furnace top hopper, at the moment, a first furnace top material level in the current furnace top hopper is recorded, and a hopper anti-bridging mode is started; and if the raw materials do not exist in the furnace top hopper, a feeding mode is started. Through the method, faults in the hopper can be effectively detected, the feeding efficiency of the system is improved, and the feeding energy consumption is reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of raw material storage, transportation and feeding, and more specifically to a modular biomass raw material feeding control method. Background Art

[0002] Feeding is one of the key links in the biomass gasification energy supply system. Automatic feeding can relieve the pressure of operators monitoring the panel, improve the automation level of the project, more precisely control the supply of raw materials, and improve the operating efficiency of the system.

[0003] Currently, most domestic biomass gasification projects adopt manual feeding. That is, operators judge whether feeding is needed through the monitoring screen, and then the driver drives a forklift to shovel the raw materials into the hopper, and the conveyor belt located below the hopper then sends the raw materials into the gasification furnace. This feeding method has three disadvantages. First, the belt conveyor usually starts in advance, and then the personnel go to the storage yard to shovel materials, resulting in energy waste. Second, the feeding is not precise enough and not timely enough. Third, it requires full-time personnel with a forklift driver's license and needs to constantly travel back and forth between the control room and the storage yard, with extremely low personnel efficiency.

[0004] The existing modular biomass raw material storage and transportation device adopts a conventional sequential control method. By judging the material level height in the ground hopper, the opening and closing of the screw distributor and the inlet and outlet valves of each silo are controlled to complete the feeding and replenishment process of each silo. The following problems exist:

[0005] 1. By detecting the material level of the raw materials in the hopper to control the storage and transportation device for feeding, the system is incomplete, and the conveyor belt requires an additional control system for control;

[0006] 2. It is impossible to judge the failure of raw material bridging in the hopper;

[0007] 3. The motor runs at a fixed frequency, which is likely to cause energy waste.

[0008] Therefore, how to effectively detect the faults in the hopper, improve the feeding efficiency of the system, and reduce the energy consumption of feeding is an urgent problem to be solved by those skilled in the art. Summary of the Invention

[0009] In view of the above problems, the present invention provides a modular biomass raw material feeding control method to at least solve some of the technical problems mentioned in the above background art.

[0010] To achieve the above object, the present invention adopts the following technical solutions:

[0011] A modular biomass raw material feeding control method is used to control the raw materials to be transported from the biomass silo unit to the gasification furnace unit; the gasification furnace unit includes a hopper on the top of the furnace and a gasification furnace; it includes:

[0012] Monitor the falling speed of the raw materials in the gasifier in real time; when the falling speed of the raw materials in the gasifier is greater than the preset speed value, detect whether there are raw materials in the top hopper.

[0013] If there are raw materials in the top hopper, it is determined that there is a raw material bridging in the top hopper. At this time, record the first top hopper level in the current top hopper and start the hopper anti-bridging mode.

[0014] If there are no raw materials in the top hopper, start the feeding mode.

[0015] Further, the hopper anti-bridging mode specifically includes:

[0016] Destroy the raw material bridging through the hopper anti-bridging device installed in the top hopper.

[0017] Further, after the hopper anti-bridging mode ends, detect the second top hopper level in the current top hopper again.

[0018] If the second top hopper level is less than the first top hopper level, it is feedback that the raw material bridging has been processed. At this time, start the feeding mode; otherwise, give an alarm.

[0019] Further, the feeding mode includes:

[0020] Open the bottom bin discharge valve in the biomass bin unit; the biomass bin unit includes a plurality of bins stacked one above the other.

[0021] Calculate the raw material transportation frequency according to the falling height of the material level in the gasifier and the falling speed of the raw materials in the gasifier.

[0022] Transport the raw materials from the bottom bin discharge valve to the top hopper according to the raw material transportation frequency.

[0023] Transport the raw materials in the top hopper to the gasifier, and at the same time, detect the change value of the raw material height in the gasifier in real time, and adaptively adjust the raw material transportation frequency according to the raw material height change value.

[0024] Further, the calculating the raw material transportation frequency according to the falling height of the material level in the gasifier and the falling speed of the raw materials in the gasifier specifically includes:

[0025] Divide a plurality of first height intervals according to the upper limit corresponding to the falling height of the material level in the gasifier, and each first height interval corresponds to a gasifier load.

[0026] Divide a plurality of second height intervals according to the falling height when the raw materials in the gasifier are at full load, and each second height interval corresponds to a state of the falling speed of the raw materials in the gasifier.

[0027] It is divided into multiple frequency intervals according to the comprehensive operating frequency of the raw material transportation motor, and each frequency interval corresponds to a raw material transportation speed state;

[0028] Establish the fuzzy subset mapping relationship corresponding to the gasifier load, the raw material descent speed state in the furnace, and the raw material transportation speed state;

[0029] For the fuzzy subset mapping relationship, use the triangular membership function to calculate the membership degrees of the raw material level drop height and the raw material descent speed in the furnace; then use the centroid method to defuzzify and calculate the raw material transportation frequency.

[0030] Further, in the process of transporting the raw materials from the valve of the bottom bin discharge port to the top hopper of the furnace:

[0031] Obtain the real-time top hopper level and determine whether the real-time top hopper level is greater than the first preset level value; if so, start the hopper anti-bridging mode in the state of starting the feeding mode;

[0032] When the hopper anti-bridging mode ends, if the real-time top hopper level is still greater than the first preset level value, give an alarm and stop the feeding mode.

[0033] Further, in the feeding mode, layer by layer monitor the level of each bin in the biomass bin unit;

[0034] When the level of the target bin is lower than the second preset level value, open the inlet valve of the target bin and the outlet valve of the upper layer bin at the same time to replenish the target bin.

[0035] Further, when opening the inlet valve of the target bin and the outlet valve of the upper layer bin, start the raw material transmission device in the target bin;

[0036] Based on the height difference between the inlet level and the outlet level corresponding to the target bin, as well as the raw material transportation frequency, adjust the movement frequency of the raw material transmission device.

[0037] Further, based on the height difference between the inlet level and the outlet level corresponding to the target bin, as well as the raw material transportation frequency, adjust the movement frequency of the raw material transmission device; specifically including:

[0038] According to the preset level height difference, it is divided into multiple height difference intervals, and each height difference interval corresponds to a bin internal balance state; each bin internal balance state corresponds to a raw material transmission device movement speed state; construct a height difference fuzzy subset according to the height difference interval, the bin internal balance state, and the raw material transmission device movement speed state;

[0039] Based on the height difference between the inlet material level and the outlet material level corresponding to the target bin, if the height difference is greater than a preset difference, then in combination with the height difference fuzzy subset, calculate the height difference membership degree;

[0040] Perform defuzzification according to the height difference membership degree to obtain the initial frequency of the raw material transmission device;

[0041] Compare the initial frequency of the raw material transmission device with the raw material transportation frequency, and take the maximum value as the movement frequency of the raw material transmission device.

[0042] Furthermore, install a plurality of level gauges at the inlet and outlet of the target bin respectively, for obtaining a plurality of inlet material levels and a plurality of outlet material levels;

[0043] Select the maximum value of the inlet material level and the minimum value of the outlet material level among them for height difference calculation.

[0044] As can be seen from the above technical solutions, compared with the prior art, the present invention discloses a modular biomass raw material feeding control method, which has the following beneficial effects:

[0045] The present invention adds a raw material bridging judgment and alarm function in the top hopper of the furnace, avoiding problems such as the feeding device still continuing to feed after raw material bridging, while the operator cannot detect the fault, resulting in production interruption.

[0046] The present invention introduces a fuzzy control algorithm to automatically feed according to the change amount of the material level in the furnace, and can realize the adaptive adjustment of the feeding amount according to the boiler load, achieving the purpose of controlling the feeding amount, reducing the workload of manual feeding by operators, and improving the feeding efficiency.

[0047] Next, through the drawings and embodiments, the technical solutions of the present invention will be further described in detail. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the drawings in the following description are only the embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained according to the provided drawings without creative efforts.

[0049] Figure 1 It is a schematic flow chart of the modular biomass raw material feeding control method provided by the embodiment of the present invention.

[0050] Figure 2 It is a schematic structural diagram of the modular biomass raw material feeding control system provided by the embodiment of the present invention.

[0051] Figure 3Schematic diagram of the positional relationship between the ground feeding screw and the raw material conveyor belt provided by the embodiment of the present invention.

[0052] Figure 4 In the feeding mode provided by the embodiment of the present invention, it is a schematic diagram of the control flow for preventing bridging in the hopper.

[0053] Figure 5 Schematic diagram of adjusting the movement frequency of the raw material transmission device in the silo provided by the embodiment of the present invention. Detailed implementation manners

[0054] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0055] The embodiment of the present invention discloses a modular biomass raw material feeding control method, which is applied to a modular biomass raw material feeding control system to realize the control of transporting raw materials from the biomass silo unit to the gasification furnace unit; wherein, the gasification furnace unit includes a furnace top hopper and a gasification furnace; the raw materials are used for transporting and storing blocky, flaky, granular, and powdery biomass raw materials in the fields of biomass energy supply, carbon production, heat supply, power generation, etc.

[0056] The modular biomass raw material feeding control method is as follows Figure 1 As shown, it includes the following steps:

[0057] Real-time monitor the falling speed of the raw materials in the furnace corresponding to the gasification furnace; when the falling speed of the raw materials in the furnace is greater than the preset speed value, it is regarded as meeting the start condition of the feeding system; at this time, the feeding system should be started to supplement raw materials to the gasification furnace.

[0058] After starting the feeding system, detect whether there are raw materials in the furnace top hopper; if there are raw materials in the furnace top hopper, it is determined that there is bridging of raw materials in the furnace top hopper. At this time, record the current furnace top material level in the furnace top hopper, denoted as the first furnace top material level, and start the hopper anti-bridging mode; if there are no raw materials in the furnace top hopper, start the feeding mode.

[0059] Next, the modular biomass raw material feeding control system will be specifically described.

[0060] The modular biomass raw material feeding control system includes a biomass silo unit, a gasification furnace unit, a transportation unit, and a control unit; as shown in Figure 2 wherein:

[0061] 1. Biomass silo unit

[0062] (1) The biomass silo unit consists of multiple silos stacked vertically. The bottom silo is called the bottom bin, and all silos except the bottom bin are mobile storage and transportation bins. Both the bottom bin and the mobile storage and transportation bins are modified from standard 20-foot or 40-foot containers and are configured according to the project scale. When using biomass wood chips as raw materials, when the three-layer 20-foot containers are full, it can meet the usage of a 15t gasifier for about 3 hours, and the two-layer mobile storage and transportation bins can meet the usage for about 2 hours. Therefore, the operator only needs to replace the silos every about 2 hours according to the signal sent by the automatic feeding system, without the need to frequently drive a forklift for feeding operations;

[0063] (2) The top surface of the bottom bin has a feed inlet, and the side surface has a discharge outlet, both of which are controlled by electric slide gates to control the entry and exit of raw materials;

[0064] (3) The top surface and the bottom surface of the mobile storage and transportation bin are respectively provided with a feed inlet and a discharge outlet, and electric slide gates are used to control the entry and exit of raw materials;

[0065] (4) The inner bottom plate of each silo is provided with a raw material transmission device. First, it can push the raw materials towards the discharge outlet during discharging to accelerate the transportation of raw materials; second, when feeding the raw materials into this silo, it can push the raw materials stacked near the feed inlet towards the discharge outlet direction to make the raw materials more evenly distributed in the silo;

[0066] (5) The speed of the raw material transmission device can be adjusted according to the height difference between the inlet material level and the outlet material level in the silo;

[0067] (6) Multiple level sensors are set in each silo, including but not limited to ultrasonic, radar, capacitive and other sensors. The control system of the present invention compares the data of multiple level sensors to determine the evenness of the raw material stacking in the silo, thereby controlling the movement of the raw material transmission device in the silo;

[0068] 2. Gasifier unit

[0069] (1) The gasifier unit includes a top hopper and a gasifier;

[0070] (2) At least two level sensors are set in the top hopper. The top hopper level in the top hopper is used to judge whether there is a situation of raw material bridging in the top hopper.

[0071] 3. Transportation unit

[0072] (1) The transportation unit includes a ground feeding screw, a raw material conveyor belt and a top feeding screw;

[0073] (2) The ground feeding screw is used to convey raw materials from the bottom bin to the raw material conveyor belt, and then convey the raw materials from the raw material conveyor belt to the top hopper; moreover, the ground feeding screw adopts frequency conversion control, which can control the transmission speed to the raw material conveyor belt; the conveyor belt adopts frequency conversion control, which can control the feeding speed to the top hopper; for the positional relationship diagram of the ground feeding screw and the raw material conveyor belt, please refer to Figure 3 as shown;

[0074] (3) In this system, the ground feeding screw and the raw material conveyor belt are arranged in the same direction. The discharge hopper of the ground feeding screw directly feeds the raw materials to the raw material conveyor belt, and the ground hopper is cancelled.

[0075] (4) The top feeding screw is used to convey raw materials from the top hopper to the gasifier; moreover, the top feeding screw adopts frequency conversion control, which can control the feeding speed into the gasifier;

[0076] 4. Control unit

[0077] The control unit adopts the fuzzy control method to realize the automatic feeding of the feeding system according to the load condition of the gasifier adaptively.

[0078] Next, the above-mentioned hopper anti-bridging mode and feeding mode will be described in detail respectively.

[0079] 1. Hopper anti-bridging mode:

[0080] 1.1 Operations related to the hopper anti-bridging mode:

[0081] Through the hopper anti-bridging device installed in the top hopper, the raw material bridging in the top hopper is destroyed; among them, the hopper anti-bridging device is an air cannon or a stirring and crushing device;

[0082] 1.2 Operations after the hopper anti-bridging mode ends:

[0083] When the hopper anti-bridging mode ends, detect the top hopper level in the current top hopper, denoted as the second top hopper level; compare the second top hopper level with the above-mentioned first top hopper level: if the second top hopper level is less than the first top hopper level, it means that the raw material bridging has been successfully destroyed and the top hopper level has dropped smoothly. At this time, feedback that the raw material bridging has been processed and start the feeding mode; otherwise, it means that the raw material bridging still exists. At this time, give an alarm to notify the operator to conduct on-site treatment.

[0084] 2. Feeding mode:

[0085] 2.1 Operations related to the feeding mode:

[0086] Open the bottom bin discharge port valve in the biomass bin unit; the biomass bin unit includes a plurality of bins stacked up and down, and the bottom bin is called the bottom bin;

[0087] Calculate the raw material transportation frequency according to the height of the material level drop in the furnace and the dropping speed of the raw materials in the furnace;

[0088] Transport the raw materials from the discharge port valve of the bottom bin to the hopper at the top of the furnace according to the raw material transportation frequency; specifically, first, start the ground feeding screw according to the raw material transportation frequency, and transport the raw materials from the discharge port valve of the bottom bin to the raw material conveyor belt through the ground feeding screw; then, start the raw material conveyor belt according to the raw material transportation frequency, and transport the raw materials to the hopper at the top of the furnace;

[0089] After detecting the change in the material level of the feeding hopper at the top of the furnace, start the feeding screw at the top of the furnace to feed the raw materials into the gasifier; at the same time, continuously and adaptively adjust the raw material transportation frequency of the motor of the feeding system according to the change value of the raw material height in the gasifier.

[0090] In the embodiment of the present invention, the ground feeding screw, the conveyor belt, the feeding screw at the top of the furnace, and the raw material conveying device in the bin all adopt frequency conversion adjustment. The starting logic of the equipment is optimized, and the above equipment is started in sequence according to the raw material flow direction, improving the system efficiency and reducing the energy consumption; the present invention incorporates the control of the raw material conveyor belt into the control system to form a complete raw material conveying system from the raw material storage bin to the feeding port of the gasifier.

[0091] 2.2. Related operations of "calculating the raw material transportation frequency according to the height of the material level drop in the furnace and the dropping speed of the raw materials in the furnace":

[0092] (1) Establish the corresponding fuzzy subset mapping relationship among the gasifier load, the dropping speed state of the raw materials in the furnace, and the raw material transportation speed state:

[0093] Divide multiple first height intervals according to the upper limit corresponding to the height of the material level drop in the furnace, and each first height interval corresponds to a gasifier load;

[0094] Divide multiple second height intervals according to the dropping height when the raw materials in the gasifier are at full load, and each second height interval corresponds to a dropping speed state of the raw materials in the furnace;

[0095] Divide into multiple frequency intervals according to the comprehensive operation frequency of the raw material transportation motor, and each frequency interval corresponds to a raw material transportation speed state;

[0096] Construct a fuzzy subset mapping relationship according to the obtained fuzzy subsets corresponding to the gasifier load, the dropping speed state of the raw materials in the furnace, and the raw material transportation speed state;

[0097] The example is as follows:

[0098] Taking a 15t biomass gasifier as an example, assuming the raw material is wood chips with a bulk density of 250 kg / m 3 When the gas production rate is 2 - 3 Nm3 When it is [unit not specified] / kg, the hourly raw material consumption is about 4.5 - 3.05t, and the inner diameter D of the gasifier is set to 4m;

[0099] The absolute value of the upper limit of the drop height of the material level in the furnace is 1m. The interval is divided into [0, 0.25], (0.25, 0.5], (0.5, 0.75], (0.75, 1]. The corresponding fuzzy subsets of the gasifier load are: low load MiL, relatively low load LL, medium load ML, high load HL;

[0100] The drop rate of the material level in the furnace is calculated according to the minimum gas production rate of 2 Nm 3 / kg. The drop height of the raw materials at full load is 2.4 cm / min. The interval is divided into [0, 0.6], (0.6, 1.2], (1.2, 1.8], (1.8, 2.4]. The corresponding fuzzy subsets of the raw material drop rate of the gasifier are: low speed MiV, relatively low speed LV, medium speed MV, high speed HV;

[0101] The interval of the comprehensive operating frequency of the motor calculated by the system is divided into 0Hz, (0, 20]Hz, (20, 40]Hz, (40, 50]Hz. The corresponding fuzzy subsets are shutdown C1, low speed C2, medium speed C3, high speed C4;

[0102] According to the fuzzy subsets corresponding to the gasifier load, the state of the raw material drop speed in the furnace, and the state of the raw material transportation speed obtained above, construct the fuzzy subset mapping relationship as shown in Table 1 below:

[0103] Table 1: Fuzzy subset mapping relationship

[0104]

[0105]

[0106] (2) According to the above fuzzy subset mapping relationship, use the triangular membership function to calculate the membership degrees of the drop height of the material level in the furnace and the drop speed of the raw materials in the furnace; then use the centroid method to defuzzify and calculate the raw material transportation frequency;

[0107] (2.1) The calculation principle of the above triangular membership function is as follows:

[0108] According to the control requirements of the embodiments of the present invention, let the coordinates of the triangle vertices be a, b, c (a < b < c). For x in the domain of discourse, the expression of the triangular membership function μ(x) is:

[0109] When x < a, μ(x) = 0;

[0110] When a ≤ x < b,

[0111] When b ≤ x ≤ c,

[0112] When x > c, μ(x) = 0.

[0113] Using the centroid method for defuzzification calculation, still set parameters a / b / c, and the calculation formula is as follows:

[0114] First, calculate the membership degree of the output fuzzy subset:

[0115]

[0116] Where: μ(x) is obtained by taking the minimum according to the membership degree calculated based on the input conditions according to the minimum-taking principle.

[0117] Calculate the centroid of the output domain, that is, the output result of defuzzification:

[0118]

[0119] (2.2) Based on the above calculation principle of the triangular membership function, an example of calculating the raw material transportation frequency is as follows:

[0120] ① Suppose the system detects that the height of the material level in the furnace drops by 0.8m, and the dropping speed of the raw materials in the furnace is 2.0cm / min;

[0121] ② Calculate the corresponding membership degree of the height of the material level drop in the furnace based on the triangular membership function:

[0122] Low load MiL: [0, 0.25]: Parameter a = 0, b = 0.125, c = 0.25

[0123] Lower load LL: (0.25, 0.5]: Parameter a = 0.25, b = 0.375, c = 0.5

[0124] Medium load ML: (0.5, 0.75]: Parameter a = 0.5, b = 0.625, c = 0.75

[0125] High load HL: (0.75, 1]: Parameter a = 0.75, b = 0.875, c = 1

[0126] Because 0.8 belongs to the high load HL subset, calculate its membership degree in the high load HL subset as follows:

[0127]

[0128] ③ Calculate the corresponding membership degree of the dropping speed of the raw materials in the furnace based on the triangular membership function:

[0129] Low speed MiV: [0, 0.6]: Parameter a = 0, b = 0.3, c = 0.6

[0130] Lower speed LV: (0.6, 1.2]: Parameters a = 0.6, b = 0.9, c = 1.2

[0131] Medium speed MV: (1.2, 1.8]: Parameters a = 1.2, b = 1.5, c = 1.8

[0132] High speed HV: (1.8, 2.4]: Parameters a = 1.8, b = 2.1, c = 2.4

[0133] Since 2.0 belongs to the high - speed interval, calculate its membership degree in the high - speed HV subset as follows

[0134]

[0135] ③ According to the minimum - taking principle of the above two membership - degree calculation results, the membership degree of the output frequency in the high - speed C4 is 0.4; according to the fuzzy subset mapping relationship (i.e., Table 1 above), the high - speed C4 (40, 50] Hz is output.

[0136] ④ Conduct defuzzification calculation.

[0137] The output comprehensive - frequency fuzzy subsets are still set as triangular functions, with parameters a = 40, b = 45, c = 50. Calculate the centroid of the fuzzy subset high - speed C4 (40, 50] Hz:

[0138]

[0139] That is, when the raw - material descending height is 0.8 m and the descending speed is 2.0 cm / min, the comprehensive frequency f cen = 45 Hz calculated by the fuzzy control system is output to the frequency converters of each motor to control the operation of the motors.

[0140] 2.3. Related operations during the feeding mode process:

[0141] (1) During the process of transporting raw materials from the bottom - bin discharge - port valve to the top - of - furnace hopper, as Figure 4 shown:

[0142] Obtain the real - time top - of - furnace material level and determine whether the real - time top - of - furnace material level is greater than the first preset material - level value (for example, 1 / 2 of the top - of - furnace hopper); if so, it is determined that raw - material bridging occurs in the top - of - furnace hopper. At this time, start the hopper anti - bridging mode in the state of starting the feeding mode to break the raw - material bridging; after the hopper anti - bridging mode ends, if the real - time top - of - furnace material level is still greater than the first preset material - level value, it means that the raw - material bridging still exists. At this time, give an alarm, notify the operating personnel to conduct on - site treatment, and stop the feeding mode.

[0143] (2) During the feeding mode, layer - by - layer monitor the material level of each bin in the biomass bin unit;

[0144] When the material level in the target silo is lower than the second preset material level value, the inlet valve of the target silo and the outlet valve of the upper-layer silo are opened simultaneously to replenish the target silo.

[0145] When opening the inlet valve of the target silo and the outlet valve of the upper-layer silo, start the raw material transfer device in the target silo, and adjust the movement frequency of the raw material transfer device in the target silo by integrating the height difference between the inlet material level and the outlet material level corresponding to the target silo, as well as the raw material transportation frequency. This control process runs until the bottom silo and the intermediate silos are full, which can empty the upper-layer silos as soon as possible and improve the turnover rate of the silos.

[0146] (3) The related operations of "adjusting the movement frequency of the raw material transfer device in the target silo by integrating the height difference between the inlet material level and the outlet material level corresponding to the target silo, as well as the raw material transportation frequency" are as Figure 5 shown:

[0147] According to the preset height difference of the material level, it is divided into multiple height difference intervals, and each height difference interval corresponds to a kind of in-silo balance state; each kind of in-silo balance state corresponds to a kind of movement speed state of the raw material transfer device; a height difference fuzzy subset is constructed according to the height difference interval, the in-silo balance state, and the movement speed state of the raw material transfer device;

[0148] Install multiple level gauges at the inlet and outlet of the target silo respectively to obtain multiple inlet material levels and multiple outlet material levels; select the maximum value of the inlet material level and the minimum value of the outlet material level for height difference calculation.

[0149] If the calculated height difference is greater than the preset difference (for example, 15 cm), then combine the height difference fuzzy subset to calculate the height difference membership degree; perform defuzzification according to the height difference membership degree to obtain the initial frequency of the raw material transfer device;

[0150] Compare the initial frequency of the raw material transfer device with the raw material transportation frequency, and take the maximum value as the movement frequency of the raw material transfer device.

[0151] The example is as follows:

[0152] Divide the level sensor into two areas, the inlet area and the outlet area, from the inlet direction to the outlet direction of the feed port, as the sampling area for the logical operation of the movement frequency of the raw material conveying device;

[0153] Set the height difference between the material levels at the feed port and the discharge port to 30 cm, and divide the intervals into [0,10], (10,20], (20,30], corresponding to the fuzzy subsets of balance B, relatively balanced CB, and unbalanced IB, and the corresponding output subsets are low speed LV[0,20], medium speed MV(20,40], and high speed HV(40,50];

[0154] The control system separately collects the material levels in two areas, namely the incoming area and the outgoing area, and compares the material levels collected in these areas. For example, in the incoming area, 3 level gauges are set as a / b / c respectively, and the collected material levels are 1.1m / 1.2m / 1.25m respectively. Then the system selects the maximum value of 1.25m as the calculation basis. In the outgoing area, 3 level gauges are set as d / e / f respectively, and the collected material levels are 1.1 / 1.2 / 1.1 respectively. Then the system selects the minimum value of 1.1 in this area as the calculation basis;

[0155] After comparison, the height difference of the raw materials between the incoming area and the outgoing area is 0.15m, which is in the relatively balanced CB interval. The membership function relationship is calculated according to the triangular membership function as follows:

[0156]

[0157] According to the deviation membership degree 1 of the raw material height with respect to the fuzzy subset relatively balanced CB, the corresponding output belongs to the medium-speed MV fuzzy subset, and the universe of discourse interval is (20, 40]. The defuzzification calculation is based on the material height difference, and the control frequency of the raw material conveying device calculated by the control system is as follows:

[0158]

[0159] That is, according to the raw material height difference, the output frequency of the raw material conveying device in the bin should be 30Hz. Compared with the raw material transportation frequency of 45Hz calculated according to the boiler load, the system outputs a frequency of 45Hz for the raw material conveying device in the bin.

[0160] In summary, the embodiment of the present invention provides a modular biomass raw material feeding control method for raw material storage and automatic feeding in biomass gasification projects. By using the fuzzy control method, the operating frequencies of the ground feeding screw, the raw material conveyor belt, and the motor of the top feeding screw in the gasification furnace are calculated according to the descending height and descending speed of the raw materials in the gasification furnace. By real-time monitoring the change of the material level in the gasification furnace, the gasification furnace can adaptively adjust the feeding amount according to the load, achieving the purpose of unmanned and intelligent feeding, avoiding the waste of resources caused by the premature start of the electric device, and improving the utilization efficiency and economic benefits of the system.

[0161] In this specification, the various embodiments are described in a progressive manner. Each embodiment focuses on the differences from other embodiments. For the same and similar parts between the various embodiments, reference can be made to each other.

[0162] The foregoing description of the disclosed embodiments enables those skilled in the art to practice or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Thus, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A modular biomass raw material feeding control method, characterized in that: Used to control the transportation of raw materials from the biomass silo unit to the gasifier unit; the gasifier unit includes a furnace top hopper and a gasifier; including: Real-time monitoring of the falling speed of the raw materials in the gasification furnace; when the falling speed of the raw materials in the furnace is greater than a preset speed value, detecting whether there is raw material in the hopper on the furnace top; If there is raw material in the furnace top hopper, it is determined that there is raw material bridging in the furnace top hopper, and at this time, the first furnace top material level in the current furnace top hopper is recorded, and the hopper anti-bridging mode is started; If there is no raw material in the furnace top hopper, the loading mode is started.

2. A modular biomass raw material feeding control method according to claim 1, characterized in that: The hopper anti-bridging mode specifically includes: The raw material bridging is destroyed by a hopper anti-bridging device installed in the furnace top hopper.

3. A modular biomass raw material feeding control method according to claim 1, characterized in that: When the hopper anti-bridging mode ends, the second furnace top material level in the current furnace top hopper is detected again; If the second furnace top material level is lower than the first furnace top material level, it is fed back that the raw material bridging has been processed and the loading mode is started; otherwise, an alarm is issued.

4. A modular biomass raw material feeding control method according to claim 1, characterized in that: The feeding mode includes: Opening the bottom bin outlet valve in the biomass silo unit; the biomass silo unit comprises a plurality of silos stacked up and down; Calculate the raw material transportation frequency according to the falling height of the material level in the furnace and the falling speed of the raw materials in the furnace; According to the raw material transportation frequency, the raw materials are transported from the bottom bin outlet valve to the furnace top hopper; The raw materials in the furnace top hopper are transported to the gasifier, and the height change value of the raw materials in the gasifier is detected in real time, and the raw material transportation frequency is adaptively adjusted according to the raw material height change value.

5. A modular biomass raw material feeding control method according to claim 4, characterized in that: The method of calculating the raw material transportation frequency according to the falling height of the material level in the furnace and the falling speed of the raw materials in the furnace specifically includes: According to the upper limit corresponding to the height of the material level drop in the furnace, a plurality of first height intervals are divided, and each first height interval corresponds to a gasification furnace load; According to the descending height of the raw materials in the gasifier when it is fully loaded, a plurality of second height intervals are divided, and each second height interval corresponds to a descending speed state of the raw materials in the furnace; According to the comprehensive operating frequency of the raw material transport motor, it is divided into multiple frequency intervals, and each frequency interval corresponds to a raw material transport speed state; Establish the fuzzy subset mapping relationship between the gasifier load, the raw material descending speed state in the furnace and the raw material transportation speed state; The fuzzy subset mapping relationship is used to calculate the membership of the material level drop height and the raw material drop speed in the furnace using the triangular membership function; the centroid method is then used to defuzzify and calculate the raw material transportation frequency.

6. A modular biomass raw material feeding control method according to claim 4, characterized in that: In the process of transporting the raw materials from the bottom bin outlet valve to the furnace top hopper: Obtain the real-time furnace top material level, and determine whether the real-time furnace top material level is greater than the first preset material level value; if so, start the hopper anti-bridging mode in the state of turning on the feeding mode; After the hopper anti-bridging mode ends, if the real-time furnace top material level is still greater than the first preset material level value, an alarm is issued and the feeding mode is stopped.

7. A modular biomass raw material feeding control method according to claim 4, characterized in that: In the loading mode, the material level of each silo in the biomass silo unit is monitored layer by layer; When the material level of a target silo is lower than a second preset material level value, the inlet valve of the target silo and the outlet valve of the upper silo are opened simultaneously to replenish the target silo.

8. A modular biomass raw material feeding control method according to claim 7, characterized in that: While opening the inlet valve of the target silo and the outlet valve of the upper silo, starting the raw material conveying device in the target silo; The movement frequency of the raw material transmission device is adjusted based on the height difference between the inlet material level and the outlet material level corresponding to the target silo and the raw material transportation frequency.

9. A modular biomass raw material feeding control method according to claim 8, characterized in that: The step of adjusting the movement frequency of the raw material transmission device based on the height difference between the inlet material level and the outlet material level corresponding to the target silo and the raw material transportation frequency specifically includes: According to the preset material level height difference, it is divided into multiple height difference intervals, each height difference interval corresponds to a warehouse balance state; each warehouse balance state corresponds to a raw material transmission device movement speed state; according to the height difference interval, warehouse balance state and raw material transmission device movement speed state, a height difference fuzzy subset is constructed; Based on the height difference between the inlet material level and the outlet material level corresponding to the target silo, if the height difference is greater than a preset difference, the height difference membership is calculated by combining the height difference fuzzy subset; Defuzzification is performed according to the height difference membership to obtain the initial frequency of the raw material transmission device; The initial frequency of the raw material transmission device is compared with the raw material transportation frequency, and the maximum value thereof is taken as the movement frequency of the raw material transmission device.

10. A modular biomass raw material feeding control method according to claim 8, characterized in that: Install multiple level meters at the inlet and outlet of the target silo to obtain multiple inlet material levels and multiple outlet material levels; Select the maximum value of the inlet material level and the minimum value of the outlet material level to calculate the height difference.

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