A hydrothermal cracking device and method with automatic constant moisture feeding

Abstract

The present invention discloses a hydrothermal cracking device and method with automatic constant moisture feeding, which includes a hydrothermal cracking tank, a manure tank, a straw feeding device, a clear liquid tank and a control module. The top of the hydrothermal cracking tank is provided with a feeding port. The manure tank, the straw feeding device and the clear liquid tank are respectively connected to the feeding port through a manure pipe, a straw channel and a clear liquid pipe, and a clear liquid pump is arranged on the clear liquid pipe. The hydrothermal cracking tank is successively provided with n pressure sensors from bottom to top, where n is an integer greater than 2, and each pressure sensor is connected to the control module. The control module is provided with a signal line connected to the clear liquid pump. By acquiring the signals of the pressure sensors through the control module, a real-time dynamic pressure curve is formed, and it is compared with a preset pressure calibration curve, judged and processed, and a regulation signal for the clear liquid pump is obtained and sent through a control algorithm. The present invention has the advantages of online measurement and adjustment of moisture.

Description

Technical Field

[0001] The present invention relates to a hydrothermal cracking device with automatic constant moisture feeding, and particularly to a feeding device for conditioning organic wastes such as livestock and poultry manure, straw, residues from agricultural product processing, forestry wastes, etc., belonging to the fields of environmental protection technology and pressure vessels. Background Art

[0002] On the one hand, with the development of rural aquaculture, the pollution of rural water, air and soil caused by breeding manure has also attracted attention. Without effective treatment, toxic substances such as germs, hormones, and antibiotics will enter the soil and water bodies through the way of using livestock and poultry manure in agriculture, posing a deep threat to the environment and also entering the food chain to cause food safety problems. And the in-situ incineration of straw is one of the important reasons for air pollution. On the other hand, the large amount of chemical fertilizers used in rural areas has led to soil compaction and decreased fertility. While the residues of chemical fertilizers endanger food safety, they also exacerbate soil and water pollution and waste a large amount of resources. With the increasing attention of the public to the environment, organic wastes such as rural livestock and poultry manure, straw, and residues from agricultural product processing cannot be discarded or burned casually, and the cost of collecting and burning them is relatively high. High-pressure sterilization, hydrolysis and then fermentation to produce fertilizer for these organic wastes is undoubtedly an effective way of resource treatment.

[0003] High-pressure hydrothermal cracking is an important link in the fertilizer production process. For a high-pressure hydrothermal hydrolysis device with shell-and-tube heating, in order to obtain better hydrolysis effect, it is necessary for the material to reach a relatively constant moisture content (such as 72% - 85%). However, in fact, the moisture content of the manure is variable and it is difficult to accurately measure online. Even if straw (the moisture content is also variable) is added, it is still difficult to obtain a constant moisture content. Summary of the Invention

[0004] The purpose of the present invention is to provide a hydrothermal cracking device and method capable of automatically feeding with constant moisture.

[0005] The present invention is realized by the following technical solutions.

[0006] A hydrothermal cracking device with automatic constant moisture feeding includes a hydrothermal cracking tank, a manure tank, a straw feeding device, a clear liquid tank and a control module. The top of the hydrothermal cracking tank is provided with a feed inlet, and the bottom is provided with a discharge outlet. The manure tank, the straw feeding device and the clear liquid tank are respectively connected to the feed inlet through a manure pipe, a straw channel and a clear liquid pipe. A manure pump is arranged on the manure pipe, and a clear liquid pump is arranged on the clear liquid pipe. The straw feeding device includes a feeding motor. The hydrothermal cracking tank is sequentially provided with n pressure sensors from bottom to top, where n is an integer greater than 2, and each pressure sensor is connected to the control module. The control module is provided with a signal line connected to the clear liquid pump.

[0007] In the above technical solution, the control module is configured to:

[0008] Obtain the pressure sensor signal, form a real-time dynamic pressure curve, compare and determine it with a preset pressure calibration curve, and obtain and send a regulating signal for the clarified liquid pump through a control algorithm.

[0009] In the above technical solution, the control module is also provided with signal lines respectively connected to the manure pump and the feeding motor.

[0010] A method for automatically and constantly feeding water includes:

[0011] Set the rotation speed of the feeding motor of the straw feeding device and / or the feeding speed of the manure pump to uniformly feed the hydrothermal cracking tank.

[0012] Pressure signal values are sequentially generated from the pressure sensors arranged from the bottom to the top of the hydrothermal cracking tank. The control module obtains the real-time pressure signal values and compares them with the preset pressure calibration curve. When the real-time pressure signal values deviate from the preset pressure calibration curve, the control module sends a regulating signal for the clarified liquid pump to start the clarified liquid pump and add the clarified liquid in the clarified liquid tank to the hydrothermal cracking tank.

[0013] When the straw and / or manure fed into the hydrothermal cracking tank reach a predetermined level, stop feeding the straw and / or manure by stopping the operation of the straw feeding device and / or the manure pump.

[0014] Continuously add the clarified liquid until the real-time dynamic pressure curve formed by the obtained real-time pressure signal values coincides with the preset pressure calibration curve, and then stop the operation of the clarified liquid pump.

[0015] In the above technical solution, the preset pressure calibration curve is obtained through a pressure curve calibration method, including: adding materials with known moisture content to the hydrothermal cracking tank, sequentially obtaining and recording the pressure signals of n pressure sensors from the bottom to the top of the hydrothermal cracking tank through the control module to form a pressure calibration curve and complete the pressure curve calibration.

[0016] In the above technical solution, the pressure curve calibration process is repeated three times and after averaging, a pressure calibration curve is formed.

[0017] The advantages and beneficial effects of the present invention include: aiming at the problem that it is difficult to accurately measure the moisture content of the original materials (including various manures, straws, other crop residues, etc.), by calibrating the pressure curve with the target product with known moisture content, and giving a clarified liquid feeding signal to regulate the moisture through the coincidence degree of the pressure curve during the operation process, it undoubtedly provides an effective measure for the moisture measurement and control in the process of using the hydrothermal reaction to produce fertilizer. Description of the Drawings

[0018] Figure 1 Schematic diagram of the feeding device with automatically constant moisture for the present invention.

[0019] In the figure: 1 - hydrothermal cracking tank; 2 - manure tank; 3 - straw feeding device; 4 - clear liquid tank; 5 - manure pump; 6 - clear liquid pump; 7 - pressure sensor. Specific embodiments

[0020] The following further describes the specific embodiments and working process of the present invention with reference to the accompanying drawings.

[0021] The orientation terms such as up, down, left, right, front, and back in this application document are based on the positional relationship shown in the drawings. If the drawings are different, the corresponding positional relationship may also change accordingly. Therefore, it should not be understood as a limitation of the protection scope.

[0022] The moisture content of the raw materials (including various manures, straws, other crop residues, etc.) is difficult to accurately measure, and the accurate moisture content of the materials cannot be determined during the actual operation process. And the moisture content of the materials entering the reaction tank is a key and sensitive component, which not only affects the heat transfer process and hydrolysis effect, but also affects the energy consumption and reaction time. Therefore, the means for online measurement and adjustment of moisture provided by the present invention is to solve these problems.

[0023] As Figure 1 shown, a hydrothermal cracking device capable of automatically feeding with constant moisture includes a hydrothermal cracking tank 1, a manure tank 2, a straw feeding device 3, a clear liquid tank 4, and a control module. The control module is connected to the clear liquid pump 6 through a signal line.

[0024] The hydrothermal cracking tank 1 is provided with a feed inlet at the top and a discharge outlet at the bottom, and both the feed inlet and the discharge outlet are provided with valves, which can be opened and closed as needed to make the hydrothermal cracking tank 1 react or feed in a sealed manner. The hydrothermal cracking tank 1 usually adopts indirect heating, using steam and / or heat transfer oil as the heating medium.

[0025] The straw feeding device 3 includes a feed motor, a silo, and a straw channel. The silo is arranged at one end of the straw channel, and the feed motor is arranged below the silo. The manure tank 2, the straw feeding device 3, and the clear liquid tank 4 are respectively connected to the feed inlet through a manure pipe, a straw channel, and a clear liquid pipe. Moreover, a manure pump 5 is arranged on the manure pipe, and a clear liquid pump 6 is arranged on the clear liquid pipe. Usually, the clear liquid pipe after the clear liquid pump 6 can often be connected to the straw channel and connected to the feed inlet of the hydrothermal cracking tank together through the straw channel. On the one hand, it can reduce the number of pipes connected to the feed inlet, and on the other hand, it can also pre-wet the straw in advance.

[0026] The hydrothermal cracking tank 1 is successively provided with n pressure sensors 7 from bottom to top, where n is an integer greater than 2. These pressure sensors include the 1st # sensor, the 2nd # sensor, up to the nth # sensor, arranged from bottom to top in sequence. And each pressure sensor is connected to the control module. The control module is used to obtain the pressure sensor signals, form a real-time dynamic pressure curve, and compare and judge it with a preset pressure calibration curve. Through a control algorithm, a regulating signal for the clear liquid pump (including start-stop signal and rotation speed signal) is obtained and sent out. And it is usually a single-loop PID (Proportion Integration Differentiation) regulating signal.

[0027] As an optimized technical solution, the control module is also provided with signal lines respectively connected to the manure pump 5 and the feeding motor, and can start and stop the manure pump 5 and the feeding motor through the control module, and even regulate their operating speeds.

[0028] The hydrothermal cracking tank 1 is used for hydrothermally cracking and producing fertilizer from pressurized water including rural wastes such as livestock and poultry manure (including cow dung, pig dung, and chicken dung) and crop straws.

[0029] The manure is loaded into the manure tank 2, and the biomass such as straws crushed to the required size is loaded into the silo. Since the feeding amount is not fixed, the rotation speed of the feeding motor of the straw feeding device 3 and / or the feeding speed of the manure pump 5 are often determined and set according to the incoming material situation to make uniform feeding into the hydrothermal cracking tank 1.

[0030] Pressure signal values are successively generated from the pressure sensors arranged from the bottom to the top of the hydrothermal cracking tank 1. The control module obtains the real-time pressure signal values and compares them with the preset pressure calibration curve. When the real-time pressure signal values deviate from the preset pressure calibration curve, the control module sends out a regulating signal for the clear liquid pump 6 to start the clear liquid pump 6 and add the clear liquid in the clear liquid tank 4 into the hydrothermal cracking tank 1.

[0031] The preset pressure calibration curve is obtained through a pressure curve calibration method, including: adding materials with known moisture content into the hydrothermal cracking tank 1, and successively obtaining and recording the pressure signals of the n pressure sensors 7 from the bottom to the top of the hydrothermal cracking tank through the control module to form a pressure calibration curve. Repeat the calibration process three times and perform arithmetic averaging on the obtained values to complete the pressure curve calibration.

[0032] The materials with known moisture content are preferably the primary products obtained after the reaction in the hydrothermal cracking tank. Since the properties of the products after the reaction are relatively uniform, the moisture content can be accurately measured, and the pressure curve calibration can be made more accurate by further adding clear liquid to make it reach the preset moisture content.

[0033] When the straw and / or manure fed into the hydrothermal cracking tank 1 reach a predetermined level (the level measurement can be carried out by visual method or contact level gauge), the feeding of straw and / or manure is stopped by stopping the operation of the straw feeding device 3 and / or the manure pump 5.

[0034] Clear liquid is continuously added until the real-time dynamic pressure curve formed by the real-time pressure signal values obtained by the control module coincides with the preset pressure calibration curve, and then the operation of the clear liquid pump is stopped.

[0035] The valve of the feed inlet is closed. By introducing saturated steam and / or heat-conducting oil into the hydrothermal cracking tank 1 to form a jacket heating, the temperature in the tank reaches 180 - 250 °C and the pressure reaches 1.2 - 2.5 MPa, and the reaction continues for 30 - 120 minutes, so that the organic degradable substances, antibiotics and other substances in it undergo high-pressure hydrothermal cracking reaction, and bacteria and viruses are killed. Then the valve of the discharge outlet is opened, and the initial reaction product enters the subsequent process for solid-liquid separation. The solid substances are used to produce solid organic fertilizer. And the liquid substances are further concentrated and separated. The concentrated liquid after separation is used to produce liquid fertilizer, while the dilute liquid obtained after separation is sent back to the clear liquid tank and reused as clear liquid. Of course, when the device is started, water can be directly used as the clear liquid.

[0036] As a preferred technical solution, the hydrothermal cracking tank can also be used as a pre-cracking tank. At this time, only need to make the temperature in the tank reach about 100 °C and the pressure reach 0.1 - 0.2 MPa, so that the organic degradable substances, antibiotics and other substances in it undergo a preliminary hydrothermal cracking reaction, and bacteria and viruses are killed to achieve a homogenization process, and then enter the next-stage hydrothermal cracking tank for the final high-pressure hydrothermal cracking reaction.

[0037] The jacket heating method of the hydrothermal cracking tank body includes that the tank body wall is arranged in a jacket type to introduce a heat exchange medium, and / or a tubular heat exchanger (surrounding type and / or upright type) is arranged in the tank body.

[0038] The above are only the preferred embodiments of the present invention and are not used to limit the present invention. For those skilled in the art, the present invention can have various changes and modifications. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A hydrothermal cracking device with automatic constant moisture feeding, characterized in that, it includes a hydrothermal cracking tank (1), a manure tank (2), a straw feeding device (3), a clear liquid tank (4) and a control module. The top of the hydrothermal cracking tank (1) is provided with a feeding port, and the bottom is provided with a discharging port. The manure tank (2), the straw feeding device (3) and the clear liquid tank (4) are respectively connected to the feeding port through a manure pipe, a straw channel and a clear liquid pipe. A manure pump (5) is arranged on the manure pipe, and a clear liquid pump (6) is arranged on the clear liquid pipe. The straw feeding device (3) includes a feeding motor; n pressure sensors (7) are arranged in sequence from the bottom to the top of the hydrothermal cracking tank (1), where n is an integer greater than 2, and each pressure sensor is connected to the control module; the control module is provided with signal lines respectively connected to the clear liquid pump (6), the manure pump (5) and the feeding motor, and the control module is configured to: Obtain in real time the pressure sensor signal values successively generated by the pressure sensors arranged from the bottom to the top of the hydrothermal cracking tank (1), form a real-time dynamic pressure curve, compare and judge it with a preset pressure calibration curve, and obtain and send out a control signal for the clear liquid pump (6); The preset pressure calibration curve is obtained through a pressure curve calibration method, including: adding materials with known moisture content to the hydrothermal cracking tank (1), and successively obtaining and recording the pressure signals of n pressure sensors from the bottom to the top of the hydrothermal cracking tank through the control module to form a pressure calibration curve, and completing the pressure curve calibration.

2. A method for automatic constant moisture feeding, which uses the hydrothermal cracking device with automatic constant moisture feeding as described in claim 1, characterized in that, it includes: Setting the rotation speed of the feeding motor of the straw feeding device (3) and / or the feeding speed of the manure pump (5) to uniformly feed materials into the hydrothermal cracking tank (1); Pressure signal values are successively generated by the pressure sensors arranged from the bottom to the top of the hydrothermal cracking tank (1). The control module obtains the real-time pressure signal values and compares them with the preset pressure calibration curve. When the real-time pressure signal values deviate from the preset pressure calibration curve, the control module sends out a control signal for the clear liquid pump (6) and starts the clear liquid pump (6) to add the clear liquid in the clear liquid tank (4) into the hydrothermal cracking tank (1); When the straw and / or manure fed into the hydrothermal cracking tank (1) reaches a predetermined level, stop the feeding of straw and / or manure by stopping the operation of the straw feeding device (3) and / or the manure pump (5); Continuously add clear liquid until the real-time dynamic pressure curve formed by the obtained real-time pressure signal values coincides with the preset pressure calibration curve, and stop the operation of the clear liquid pump.

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