Movable photovoltaic energy supply subcritical fertilizer production system for nitrogen and phosphorus emission reduction and efficiency improvement and high-humidity waste resource treatment and product application

Abstract

The invention belongs to the field of biomass subcritical fertilizer production, and particularly relates to a movable photovoltaic energy supply subcritical fertilizer production system for nitrogen and phosphorus emission reduction and efficiency improvement and high-humidity waste resource treatment and product application. Comprising a solar preheating system, a photovoltaic power supply system, an auxiliary heating system, a hydrothermal reaction system and a post-processing system, wherein the photovoltaic power supply system and the auxiliary heating system are connected with an electric load of the hydrothermal reaction system; the hydrothermal reaction system is respectively connected with the solar preheating system and the post-treatment system. According to the method, the hydrothermal carbon liquid is subjected to desalination treatment by utilizing an electrodialysis technology and then returned to the field for utilization, the desalination rate of the carbon liquid is 45-90% through electrodialysis, the conductivity of the desalted carbon liquid is 1.40-6.75 mS / cm, and the yield of crops is obviously increased through the desalted carbon liquid; wherein the chlorophyll content is increased by 25.5%-67.5%, and the fresh weight is increased by 18.5%-175%; the length of the lettuce root system is increased by 37.0%-98.2%, and the high desalination degree can avoid the negative influence of salt stress on the lettuce root system.

Description

Technical Field

[0001] The present invention belongs to the field of biomass subcritical fertilizer production, and specifically relates to a mobile photovoltaic-powered subcritical fertilizer production system and product application for nitrogen and phosphorus emission reduction and efficiency improvement and high-humidity waste resource disposal. Background Art

[0002] The loss of nutrients such as nitrogen and phosphorus in agricultural production is the main source of nutrient surplus in farmland ecosystems, water bodies and wetland ecosystems, and is an important cause of non-point source pollution. Hydrothermal carbonization (HTC) is a new material conversion process that can convert high-water-content raw materials into hydrothermal charcoal and charcoal liquid in a short time under relatively low temperature (<250℃) and energy input conditions. Hydrothermal charcoal can be used as fuel, soil conditioner and new carbon material, and charcoal liquid contains a large number of nutrients and is rich in amino acids, which can be used as liquid fertilizer. Both have certain economic value. This technology has attracted widespread attention from the international community and provides a new solution for waste treatment and resource recycling. Most of the existing hydrothermal reaction equipment still uses traditional electric heating or boiler hot water heating, which consumes a large amount of non-renewable energy, has high reaction energy consumption and high operation and maintenance costs, which seriously restricts the large-scale production practice progress and promotion and application of hydrothermal carbonization technology. Therefore, in order to promote further research on hydrothermal carbonization technology, it is urgent to develop low-energy consumption, low-operation and maintenance cost and sustainable hydrothermal carbonization equipment. Summary of the invention

[0003] The purpose of the present invention is to provide a mobile photovoltaic-powered subcritical fertilizer production system and application thereof for nitrogen and phosphorus emission reduction and efficiency enhancement and high-humidity waste resource disposal.

[0004] In order to achieve the above objectives, the technical solution adopted by the present invention is as follows: a mobile photovoltaic-powered subcritical fertilizer production system for nitrogen and phosphorus emission reduction and efficiency improvement and high-humidity waste resource disposal, including a solar preheating system, a photovoltaic power supply system, an auxiliary heating system, a hydrothermal reaction system and a post-processing system, wherein the photovoltaic power supply system and the auxiliary heating system are connected to the hydrothermal reaction system power load; the hydrothermal reaction system is respectively connected to the solar preheating system and the post-processing system;

[0005] The solar preheating system comprises a heat pipe solar collector, a solar water tank, a PLC controller, a water pump and a stop valve; one side of the solar water tank is connected to the hydrothermal reaction system through the water pump and the stop valve, and the other side is connected to the PLC controller through a pipeline; the solar water tank is connected in parallel with the heat pipe solar collector and fixed by a bracket;

[0006] The photovoltaic power supply system includes a photovoltaic module, a photovoltaic controller, a battery pack, an inverter and a distribution box; the output end of the photovoltaic module is connected to the input end of the photovoltaic controller; the output end of the photovoltaic controller is connected to the input end of the battery pack; the output end of the battery pack is connected to the input end of the inverter; the output end of the inverter is connected to the input end of the distribution box; the output end of the distribution box is connected to the electrical load of the hydrothermal reaction system;

[0007] The auxiliary heating system includes an auxiliary heater; the output end of the auxiliary heater is connected to the electric load of the hydrothermal reaction system;

[0008] The hydrothermal reaction system comprises a feeder, a reactor, a filter press, a solid storage device and a liquid storage device; the feeder is connected to the feed port of the reactor; the discharge port of the reactor is connected to the filter press; the filter press is connected to the solid storage device and the liquid storage device respectively; the liquid storage device is connected to the electrodialysis device;

[0009] The post-treatment system comprises an electrodialysis device; the inlet of the electrodialysis device is connected to the outlet of the liquid storage device.

[0010] The solar water tank in the solar preheating system is connected to the heat pipe solar collector, the inner wall of the heat pipe solar collector is provided with a temperature sensor and is connected to the PLC controller;

[0011] The bottom of the heat pipe solar collector is fixed by a bracket;

[0012] The solar water tank is provided with a water inlet at one end and a water outlet at the other end, and a stop valve is arranged.

[0013] The photovoltaic components in the photovoltaic power supply system are at least one group and are provided with a base.

[0014] The battery pack in the photovoltaic power supply system includes at least two batteries, and the batteries are connected in series.

[0015] The feeder has a sample adding port on the top and a sample outlet on the side, and the sample outlet of the feeder is connected to the feed port of the reactor;

[0016] The reactor comprises a motor and a stirrer;

[0017] The inlet of the filter press is connected to the discharge port of the reactor and is provided with a water pump and a stop valve;

[0018] The outlet of the filter press is in communication with a solid storage device and a liquid storage device;

[0019] The product storage device used in the hydrothermal reaction stage includes a solid storage device and a liquid storage device.

[0020] The outlet of the liquid storage device is connected to the inlet of the electrodialysis device by a pipeline.

[0021] The present invention also discloses an application of a mobile photovoltaic-powered subcritical fertilizer production system for nitrogen and phosphorus emission reduction and efficiency improvement and high-humidity waste resource disposal, comprising the following steps:

[0022] In the solar water tank, the water required for the hydrothermal carbonization reaction is preheated. The process is monitored and controlled by the PLC controller. After the temperature is raised, the water is transported to the reactor through the water pump and the stop valve.

[0023] The raw materials for the hydrothermal carbonization reaction are added from the inlet of the feeder and then transported to the feed port of the reactor from the outlet of the feeder; the raw materials for the hydrothermal carbonization reaction are feces or tail vegetables, the reaction temperature is 180-260°C, the reaction time is 0.8-1.2h, the mass volume ratio of feces or tail vegetables to water in the hydrothermal carbonization reaction is 1kg:9-11L, and the feces are cow dung or pig dung; the speed of the agitator in the reactor is 200-300r / min, which is used for stirring the raw materials during the hydrothermal carbonization process; the reactor is fully closed during the hydrothermal carbonization process, and the pressure in the reactor is 1.0-1.8MPa. After the reaction is completed, the reactor is cooled; the reactor can be opened to discharge the material after the pressure is released; the product is passed into the filter press from the discharge port of the reactor with the help of a water pump and a stop valve, and the solid-liquid separation of the product is performed by the filter press method, so that the water content of the hydrothermal carbon is less than 30%, the hydrothermal carbon is stored in a solid storage device, and the carbon liquid is stored in a liquid storage device;

[0024] The carbon liquid enters the electrodialysis device from the liquid storage device, and is electrodialyzed under the conditions of DC voltage 25-35V and peristaltic pump 40-80RPM. The desalination rate is 45%-90%, the percentage is mass fraction, and the electrodialysis time is 15-120min (preferably 45-90min), to obtain a desalinated carbon liquid with a conductivity of 1.40-6.75mS / cm. The above electrodialysis operating parameters are adopted to improve the desalination speed; the carbon liquid contains almost no colloids and is suitable for desalination by membrane technology, and a reasonable electrodialysis time can reduce the soluble organic matter in the components of the hydrothermal carbon liquid, such as humic acid, fulvic acid, etc., which pollutes the ion exchange membrane; other desalination methods such as reverse osmosis and ultrafiltration are mainly aimed at obtaining fresh water and realizing water recovery, while the purpose of HAP desalination treatment in the present invention is to remove inorganic salt ions, such as sodium chloride, etc., and separate them from the liquid phase, retaining organic matter such as humic acid and some nutrients in the liquid phase, and the desalted HAP is still used as a liquid organic fertilizer or soil conditioner; other desalination technologies cannot achieve similar effects.

[0025] Taking a single reaction to process 30-50L of raw materials as an example, after the raw materials are pretreated, they are heated by the preheating system for 3-4 hours and hydrothermally reacted for 1-2 hours. After the reaction is completed and the power is cut off, it is naturally cooled and depressurized at room temperature, which takes about 12 hours. A single reaction takes about one day.

[0026] Preferably, the desalination rate of the carbon liquid is 80%-90%, and the desalinated carbon liquid with an electrical conductivity of 1.40±0.15 mS / cm is obtained.

[0027] Desalinated charcoal liquid is applied as fertilizer to the soil for plant growth. The nitrogen replacement rate of desalinated charcoal liquid is 24%-40%, and the percentage is mass fraction. For fast-growing plants, desalinated charcoal liquid is applied twice; the first application is in the seedling stage of the plant, and the second application is in the middle and late stages of plant growth. The mass ratio of the first application of desalinated charcoal liquid to the second application of desalinated charcoal liquid is 2:2.5-3.5. For wheat, desalinated charcoal liquid is applied three times, and the application amount of desalinated charcoal liquid in the base fertilizer, tillering fertilizer, and ear fertilizer stages is equivalent. By adding in batches, applying charcoal liquid at different fertilization periods, it works at different stages of plant growth; if the charcoal liquid is applied all at once, it will cause excessive concentration or excessive dosage, resulting in seedling burn.

[0028] Hydrocharcoal can also be used as fertilizer in soil for plant growth. The nitrogen replacement rate of hydrocharcoal is 15%-25%, and the phosphorus replacement rate of hydrocharcoal is 25%-35%. The percentages are mass fractions. The hydrocharcoal is manure-derived hydrocharcoal. The application amount of hydrocharcoal in the base fertilizer, tillering fertilizer, and ear fertilizer stages is equivalent. When applied, the hydrocharcoal is fully mixed with the 0-20cm surface soil. The application amount of hydrocharcoal is 0.2-2% of the surface soil. % is the mass fraction.

[0029] When desalinated carbon liquid is applied as fertilizer to the soil for plant growth, it increases the chlorophyll content of plant leaves, promotes the accumulation of plant biomass, and increases the length of plant roots.

[0030] The present invention is beneficial in that:

[0031] When the hydrothermal carbonization liquid product is directly applied to farmland, higher salt content will accelerate soil salinization, and high concentration of nutrients such as ammonia nitrogen is not conducive to plant growth, and ammonia volatilization will also occur. The present invention uses electrodialysis technology to desalinate the hydrothermal carbon liquid before returning it to the field for use. The desalination efficiency is improved by electrodialysis, and the high desalination carbon liquid significantly increases crop yields, especially greatly promoting the growth of plant roots.

[0032] The post-treatment system adopted by the present invention can effectively remove the salt in the liquid phase product carbon liquid, reduce the potential pollution to the environment, and improve the safety of the product in agricultural or other field applications.

[0033] The solar preheating system adopted in the present invention can first heat the water required by the hydrothermal reaction system to a certain temperature (90°C in summer and 50°C in winter), and directly convert a part of the solar energy into thermal energy to reduce energy loss. Taking the temperature of the hydrothermal reaction system at 180°C as an example, the energy consumption of the heating process can be reduced by about 27% to 50%.

[0034] The photovoltaic power supply system used in the present invention is provided with photovoltaic modules, which can store light energy well, and the generated electric energy drives the hydrothermal reaction system, thereby greatly reducing the energy consumption of the processing system.

[0035] The hydrothermal reaction system adopted by the present invention has strong airtightness and no secondary pollution in the reaction process. It can efficiently convert raw materials with high water content (such as tail vegetables, livestock and poultry manure, etc.) into hydrothermal charcoal and charcoal liquid with certain economic and ecological benefits, achieve a 90% reduction in the mass of the reaction raw materials and a 60% reduction in the volume, and promote the recycling of resources.

[0036] The auxiliary heating system adopted in the present invention can ensure the normal operation of the hydrothermal reaction system when photovoltaic power generation is insufficient, thereby improving the stability of the equipment. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 This is a framework diagram of a mobile photovoltaic-powered subcritical fertilizer production system for nitrogen and phosphorus emission reduction and efficiency improvement and high-humidity waste resource disposal;

[0038] Figure 2 It is a structural schematic diagram of a mobile photovoltaic-powered subcritical fertilizer production system for nitrogen and phosphorus emission reduction and efficiency improvement and high-humidity waste resource disposal;

[0039] Figure 3 Effects of different manure and hydrochar application on (a) ammonium nitrogen and (b) nitrate nitrogen concentrations in paddy field surface water;

[0040] Figure 4 The effects of different manure and their hydrochar on phosphorus concentration in rice field surface water;

[0041] Figure 5 Effects of different manure and their hydrochar application on (a) N2O emission flux and (b) cumulative emission from paddy soil.

[0042] Figure 6 Effects of different manure and their hydrochar application on (a) NH3 volatilization flux and (b) cumulative volatilization of paddy soil;

[0043] Figure 7 The effects of typical charcoal liquid and desalted charcoal liquid on the growth (biomass) of Chinese cabbage and lettuce, A, Chinese cabbage, B, lettuce;

[0044] Figure 8Effects of typical charcoal liquid and desalted charcoal liquid on biomass and root growth of Chinese cabbage and lettuce, A, chlorophyll content, B, plant fresh weight, C, plant dry weight, D, plant root length, E, Chinese cabbage root, F, lettuce root;

[0045] Fig. 9 It is the physiological index for harvesting wheat at heading stage;

[0046] Fig.10 The physiological indexes of wheat root system were harvested at heading stage;

[0047] Fig.11 Yield and quality indicators of wheat grains harvested at maturity;

[0048] In the figure: 1-photovoltaic module; 2-photovoltaic controller; 3-battery group; 4-inverter; 5-distribution box; 6-auxiliary heater; 7-PLC controller; 8-solar water tank; 9-heat pipe solar collector; 10-water pump; 11-stop valve; 12-feeder; 13-reactor; 14-filter press; 15-solid storage device; 16-liquid storage device; 17-feed port; 18-motor; 19-agitator; 20-discharge port; 21-electrodialysis device. DETAILED DESCRIPTION

[0049] The present invention is described in detail below with reference to the accompanying drawings and specific embodiments.

[0050] like Figure 1 and Figure 2 As shown, the present invention provides a mobile photovoltaic-powered subcritical fertilizer production system for nitrogen and phosphorus emission reduction and efficiency improvement and high-humidity waste resource disposal, including a solar preheating system, a photovoltaic power supply system, an auxiliary heating system, a hydrothermal reaction system and a post-processing system, wherein the photovoltaic power supply system and the auxiliary heating system are connected to the hydrothermal reaction system power load; the hydrothermal reaction system is tightly connected to the solar preheating system and the post-processing system using pipelines, and also includes a water pump 10, a stop valve 11 and other connecting devices;

[0051] The solar preheating system includes a heat pipe solar collector 9, a solar water tank 8, a PLC controller 7, a water pump 10 and a stop valve 11; one side of the solar water tank 8 is connected to the hydrothermal reaction system through the water pump 10 and the stop valve 11, and the other side is connected to the PLC controller 7 through a pipeline; the solar water tank 8 is connected in parallel with the heat pipe solar collector 9 and fixed by a bracket.

[0052] The photovoltaic power supply system includes a photovoltaic module 1, a photovoltaic controller 2, a battery pack 3, an inverter 4 and a distribution box 5; the output end of the photovoltaic module 1 is connected to the input end of the photovoltaic controller 2; the output end of the photovoltaic controller 2 is connected to the input end of the battery pack 3; the output end of the battery pack 3 is connected to the input end of the inverter 4; the output end of the inverter 4 is connected to the input end of the distribution box 5; the output end of the distribution box 5 is connected to the power load of the hydrothermal reaction system, and an off-grid system is installed.

[0053] The auxiliary heating system includes an auxiliary heater 6; the output end of the auxiliary heater 6 is connected to the electric load of the hydrothermal reaction system.

[0054] The hydrothermal reaction system includes a feeder 12, a reactor 13, a filter press 14, a solid storage device 15 and a liquid storage device 16; the feeder 12 is connected to the feed port 17 of the reactor 13 through a pipeline; the discharge port 20 of the reactor 13 is tightly connected to the filter press 14 using a pipeline, and also includes connecting devices such as a water pump 10 and a stop valve 11; the filter press 14 is connected to the solid storage device 15 and the liquid storage device 16 respectively using pipelines; the liquid storage device 16 and the electrodialysis device 21 are tightly connected through a pipeline.

[0055] The post-treatment system includes an electrodialysis device 21; the inlet of the electrodialysis device 21 and the outlet of the liquid storage device 16 are connected by a pipeline. The electrodialysis technology utilizes the selective permeability of the ion exchange membrane to selectively migrate anions and cations through the membrane under the action of an external DC electric field, and alternately forms a concentrated water chamber and a fresh water chamber in the compartment formed by the ion exchange membrane to achieve the purpose of desalination.

[0056] The solar water tank 8 in the solar preheating system is connected to the heat pipe solar collector 9, the inner wall of the heat pipe solar collector 9 is provided with a temperature sensor and is connected to the PLC controller 7;

[0057] The bottom of the heat pipe solar collector 9 is fixed by a bracket;

[0058] The solar water tank 8 is provided with a water inlet at one end and a water outlet at the other end, and a stop valve is provided.

[0059] The photovoltaic components 1 in the photovoltaic power supply system are at least one group and are provided with a base.

[0060] The battery group 3 in the photovoltaic power supply system includes at least two batteries, and the batteries are connected in series.

[0061] The feeder 12 has a sample adding port on the top and a sample outlet on the side. The sample outlet of the feeder 12 is tightly connected to the feed port 17 of the reaction kettle 13 through a pipeline.

[0062] The reactor 13 includes auxiliary devices such as a motor 18 and a stirrer 19;

[0063] The inlet of the filter press 14 is connected to the discharge port 20 of the reactor 13 by a pipeline, and is provided with connection devices such as a water pump 10 and a stop valve 11;

[0064] The outlet of the filter press 14 is connected to the solid storage device 15 and the liquid storage device 16 by pipelines;

[0065] The hydrothermal reaction stage includes a solid storage device 15 and a liquid storage device 16 .

[0066] The outlet of the liquid storage device 16 is connected to the inlet of the electrodialysis device 21 by a pipeline.

[0067] like Figure 1 As shown, the production system described in the present invention includes a solar preheating system, a photovoltaic power supply system, an auxiliary heating system, a hydrothermal reaction system and a post-processing system. The photovoltaic power supply system and the auxiliary heating system are connected to the hydrothermal reaction system with an electrical load; the hydrothermal reaction system is tightly connected to the solar preheating system and the post-processing system using pipelines.

[0068] The main function of the solar preheating system is to convert solar energy into thermal energy through the heat pipe solar collector 9 to preheat the water required for hydrothermal carbonization. The main function of the photovoltaic power supply system is to convert light energy into electrical energy through the photovoltaic module 1 to supply energy to the hydrothermal reaction system. The main function of the auxiliary heating system is to supply energy to the hydrothermal reaction system to ensure the normal operation of the equipment when photovoltaic power generation is insufficient. The main function of the hydrothermal reaction system is to perform hydrothermal carbonization reaction on the input raw materials to generate hydrothermal charcoal and charcoal liquid. The main function of the post-treatment system is to use electrodialysis technology to desalinate the charcoal liquid to reduce secondary pollution.

[0069] When the hydrothermal carbonization reaction is carried out by the production system of the present invention, the following steps are included:

[0070] First, the water required for the hydrothermal carbonization reaction is preheated in the solar water tank 8. The process is monitored and controlled by the PLC controller 7. After the temperature is raised, the water is transported to the reactor 13 through the water pump 10 and the stop valve 11.

[0071] like Figure 2As shown, the photovoltaic power supply system mainly includes a photovoltaic module 1, a photovoltaic controller 2, a battery group 3, an inverter 4 and a distribution box 5. The photovoltaic module 1 is used to convert the solar radiation energy into direct current power and is connected to the photovoltaic controller 2 through a wire; the photovoltaic controller 2 is used to regulate and control the power generated by the solar cell module, charge the battery group 3, and provide overcharge and over-discharge protection for the battery group 3; in places with large temperature differences, the photovoltaic controller 2 has a temperature compensation function; the input end of the photovoltaic controller 2 is connected to the output end of the photovoltaic module 1 through a wire, and the output end of the photovoltaic controller 2 is connected to the input end of the battery group 3 through a connecting cable;

[0072] Specifically, the photovoltaic assembly 1 is at least one group, and a base is provided, which can be installed in an open area or on a roof layer;

[0073] Specifically, the battery group 3 includes at least two batteries, each of which is connected in series and has the function of storing energy to ensure power consumption of the load; the input end of the battery group 3 is connected to the output end of the photovoltaic controller 2 through a connecting cable, and the output end of the battery group 3 is connected to the input end of the inverter 4 through a connecting cable; the battery group 3 can be set in a concrete structure.

[0074] Specifically, the inverter 4 is the core component of the photovoltaic power supply system, and its function is to convert the direct current generated by the photovoltaic cell assembly into alternating current for use by the AC load; the input end of the inverter 4 is connected to the output end of the battery pack 3 through a connecting cable, and the output end of the inverter 4 is connected to the input end of the distribution box 5 through a wire.

[0075] Specifically, the distribution box 5 functions as an isolating switch, and has lightning protection devices, overvoltage protection, and overcurrent protection functions. When the battery power is insufficient, it automatically switches to the grid power supply state and cuts off the original power supply line; the contactor contacts in the distribution box 5 are connected to the output end of the inverter 4 through a wire, and the output end of the distribution box 5 is connected to the load electrical appliances of the hydrothermal reaction system. The distribution box 5 is set near the photovoltaic power supply system and the hydrothermal reaction system.

[0076] like Figure 2 As shown, the auxiliary heating system mainly includes an auxiliary heater 6, which is used to supply power to the hydrothermal reaction system when photovoltaic power generation is insufficient to ensure normal operation of the equipment.

[0077] Specifically, the output end of the auxiliary heater 6 is connected to the load electrical equipment of the hydrothermal reaction system, and the auxiliary heater 6 is arranged near the hydrothermal reaction system.

[0078] like Figure 2 As shown, the hydrothermal reaction system includes a feeder 12, a reactor 13, a filter press 14, a solid storage device 15 and a liquid storage device 16 in sequence, and also includes a water pump 10 and a stop valve 11 connected to each device;

[0079] Specifically, the hydrothermal carbonization reaction raw materials are added from the inlet of the feeder 12 and then transported from the outlet of the feeder 12 to the feed inlet 17 of the reactor 13;

[0080] Specifically, the reactor 13 is provided with a motor 18 and a stirrer 19, the stirrer 19 has a rotation speed of 200 to 300 r / min, and is used to stir the raw materials during the hydrothermal carbonization process to improve the reaction efficiency;

[0081] Specifically, the reactor 13 is completely closed during the hydrothermal carbonization process, and the pressure inside the reactor 13 is 1.0-1.8 MPa. After the reaction is completed, the reactor 13 can be cooled by passing condensed water or naturally cooled. To ensure safe operation, the reactor 13 can be opened to discharge materials after the pressure is released;

[0082] Specifically, the product is passed from the discharge port 20 of the reactor 13 into the filter press 14 by means of a water pump 10 and a stop valve 11, and the solid-liquid separation of the product is performed by filter pressing to make the water content of the hydrothermal char less than 30%. The hydrothermal char is stored in a solid storage device 15, and the charcoal liquid is stored in a liquid storage device 16.

[0083] like Figure 2 As shown, the post-treatment system mainly includes an electrodialysis device 21;

[0084] Specifically, the carbon liquid enters the electrodialysis device 21 from the liquid storage device 16, and the salt in the carbon liquid is removed by electrodialysis to improve the safety of resource utilization of the carbon liquid.

[0085] In the embodiment of the present invention, the heat energy required for the hydrothermal carbonization reaction is provided by a solar preheating system and a photovoltaic power generation system. The solar preheating system converts solar energy into heat energy to preheat the reaction water, thereby reducing the energy loss in the conversion between solar energy and electric energy; the photovoltaic power generation system converts solar energy into electric energy, and its process energy consumption is low and its load impact resistance is strong. At the same time, an auxiliary heating system is provided to ensure the operation and processing effect under special weather conditions such as winter or continuous rain, and it has a sustainable application prospect. Through the post-processing system, the product carbon liquid is desalted to effectively reduce the salt concentration of the carbon liquid, improve the safety of the resource utilization of the carbon liquid, and contribute to the promotion and application of the hydrothermal carbonization technology.

[0086] Application examples:

[0087] (1) Preparation of hydrothermal carbon liquid:

[0088] Synthesis of hydrothermal carbon liquid: Cow dung and tail vegetables were used as raw materials, respectively, and reacted in a hydrothermal carbonization system at 220℃ and 260℃ for 1 hour; in the hydrothermal carbonization (HTC), the material ratio of cow dung or tail vegetables to water was 1kg:10L, and the pressure in the reactor was 1.5MPa. Solid hydrothermal carbon and liquid hydrothermal carbon liquid were obtained. The cow dung source hydrothermal carbon liquid prepared at 220℃ and 260℃ were recorded as CM220 and CM260, respectively; the tail vegetable source hydrothermal carbon liquid prepared at 220℃ and 260℃ were recorded as GV220 and GV260, respectively.

[0089] Table 1 Basic physical and chemical properties of hydrothermal charcoal liquids derived from feces and tailings

[0090]

[0091] Note: TN: total nitrogen; DOC: dissolved organic carbon; AP: available phosphorus; AK: available potassium.

[0092] (2) Desalination characterization of hydrothermal carbon liquid:

[0093] The preparation process of hydrothermal carbon liquid for desalination characterization is as follows: pig manure is used as raw material, reacted in a hydrothermal carbonization system at 200℃ for 1 hour; the material ratio of pig manure to water is 1kg:10L, and the obtained carbon liquid is used as the undesalted carbon liquid. Desalination is performed on the basis of the obtained carbon liquid to obtain low desalination carbon liquid and high desalination carbon liquid respectively. Electrodialysis desalination treatment test parameters: DC voltage 30V, peristaltic pump 60RPM, electrodialysis module 5 cathodes, 5 anodes, 9 5cm×10cm compartments, desalination for 30min to obtain low desalination carbon liquid, or desalination for 75min to obtain high desalination carbon liquid. 1L carbon liquid is desalted each time. The low desalination carbon liquid obtained by multiple desalination operations is mixed to obtain the final low desalination carbon liquid, and the high desalination carbon liquid obtained by multiple desalination operations is mixed to obtain the final high desalination carbon liquid. The physical and chemical properties of the undesalted carbon liquid, low desalination carbon liquid and high desalination carbon liquid were measured.

[0094] The conductivity of the carbon liquid is measured by sampling. The degree of desalination (ie, desalination rate) is determined by the change in the conductivity of the carbon liquid. Specifically, the change in the conductivity of the carbon liquid corresponds linearly to the degree of desalination.

[0095] Table 2 Basic physical and chemical properties of typical carbon liquid and desalination carbon liquid

[0096]

[0097]

[0098] (3) Pot experiment verification of desalinated charcoal liquid

[0099] A pot experiment was conducted at the experimental base of Jiangsu Academy of Agricultural Sciences in 2024. The test vegetable varieties are fast-growing cream pakchoi and Italian lettuce. The potting system is 10 kg of soil per pot (soil properties are shown in Table 4), and the effective planting area is 0.1 m2 / pot. The vegetables are planted in 8 pieces per pot. It takes about 35 days from sowing to harvesting fast-growing cream pakchoi and about 50 days for Italian lettuce. The experimental control treatment CKU is normal fertilization, equivalent to 225 kg / ha of pure N application, 90 kg / ha of P2O5 application, and 180 kg / ha of K2O application. Except for CK, all other treatments are equivalent to 225 kg / ha of pure N application, 90 kg / ha of P2O5 application, and 180 kg / ha of K2O application (that is, the total application of N, P, and K is the same as that of the CKU group). In this part of the experiment, the applied materials were HAP (non-desalted charcoal liquid, Table 2), LD-HAP (low desalted charcoal liquid, Table 2), and HD-HAP (high desalted charcoal liquid, Table 2). The nitrogen replacement rate was 24%-40%, as shown in Table 5. Daily water management used tap water irrigation. The potted experiment showed that the application of desalted charcoal liquid promoted the macroscopic growth of plants, increased the chlorophyll content of vegetable leaves, significantly promoted the accumulation of plant biomass, and promoted the root parameters of plants, among which the high desalination group showed the best effect. The results are as follows Figure 7-8 shown.

[0100] CK is a blank control; CKU is a conventional fertilization control; HAP is a control group for applying undesalted charcoal liquid; LV and HV are respectively applied with low desalination charcoal liquid and high desalination charcoal liquid, and the amount of charcoal liquid applied in LV and HV treatments is the same as that in HAP treatment; LN and HN are respectively applied with low and high desalination charcoal liquid, and the amount of charcoal liquid applied in LN and HN treatments is controlled to have the same nitrogen replacement rate as that in the HAP group. The charcoal liquid and supplementary urea are applied in the same way and at the same time. After transplanting and stabilizing the seedlings, the total amount applied to each pot is applied twice. The first time is when the seedlings are small at the beginning, and 40% of the total amount is applied. The second time is when the plants have a stronger demand for nutrition in the middle and late stages, and 60% of the total amount is applied, and evenly irrigated around the plants. The use of equal nitrogen replacement is mainly due to the high total nitrogen content in pig manure charcoal liquid, and the demand for nitrogen for vegetable growth is also the highest.

[0101] According to the arrangement of the vegetable experiment cycle, the fast-growing cream cabbage takes a 35-day cycle as an example. Transplanting begins 10 days after seedling cultivation, and the first application of charcoal liquid (40%) is made on the 15th day, 5 days after transplanting and planting, and the second application of charcoal liquid (60%) is made on the 25th day, 10 days later. Fertilizer: Superphosphate and potassium chloride are applied as base fertilizers before transplanting and planting, and urea and charcoal liquid are applied simultaneously (including the single application ratio and application time, that is, the first application of urea on the 15th day (40% of the total urea application amount), and the second application of urea on the 25th day (60% of the total urea application amount)).

[0102] According to the arrangement of the vegetable experiment cycle, Italian lettuce takes a 50-day cycle as an example. Transplanting begins 12 days after seedling cultivation, and the first application of charcoal liquid (40%) is made on the 18th day, 6 days after transplanting and planting, and the second application of charcoal liquid (60%) is made on the 38th day, 20 days later. Fertilizer: Superphosphate and potassium chloride are applied as base fertilizers once before transplanting and planting, and urea and charcoal liquid are applied simultaneously (including the single application ratio and application time, that is, the first application of urea on the 18th day (40% of the total urea application amount), and the second application of urea on the 38th day (60% of the total urea application amount)).

[0103] Effects of undesalted charcoal and desalted charcoal on the growth of Chinese cabbage and lettuce (i.e. biomass accumulation) Figure 7 shown. Figure 7 The A in the figure corresponds to the pakchoi on the 35th day. Figure 7 B in the figure corresponds to the lettuce on the 50th day.

[0104] As shown in Table 3 and Figure 8 As shown, compared with the control, each desalinated charcoal liquid treatment group increased the chlorophyll content of plant leaves, significantly promoted the accumulation of plant biomass, and promoted the root parameters of plants, among which the high desalinated charcoal liquid group showed the best effect. Compared with CK, CKU and HAP, the application of desalted charcoal liquid had a certain effect on the chlorophyll content of pakchoi leaves. Compared with the CK group, LV, HV, LN and HN increased by 35.3%, 26.3%, 30.6% and 25.5%, respectively; compared with the HAP group, LV, HV, LN and HN increased by 9.5%, 2.2%, 5.8% and 1.6%, respectively; the application of desalted charcoal liquid significantly increased the chlorophyll content of lettuce leaves. Compared with the CK group, LV, HV, LN and HN increased by 45.7%, 62.4%, 50.0% and 67.5%, respectively; compared with the HAP group, LV, HV, LN and HN increased by 37.5%, 53.2%, 41.5% and 58.1%, respectively.

[0105] Table 3 Plant growth indicators of each treatment group and control group of desalted carbon liquid

[0106]

[0107]

[0108]

[0109] In Table 3, 1-1, 1-2, 1-3, and 1-4 are 4 parallel samples.

[0110] The optimal effects of fresh weight of Chinese cabbage and lettuce appeared in the HV group. Compared with CKU and HAP, the fresh weight of Chinese cabbage increased by 19.6% and 91.4%, and the fresh weight of lettuce increased by 18.5% and 175%, respectively. The fresh weight of plants in the HAP group was lower than that in CKU, almost the same as that in CK. It can be seen that the undesalted charcoal liquid will inhibit the normal biomass accumulation of lettuce. The dry weight and fresh weight showed similar effects; the application of desalted charcoal liquid had a more significant effect on the root system of lettuce. Compared with the undesalted group, the root length of lettuce in the low desalted group increased by an average of 37.0%, and the root length of lettuce in the high desalted group increased by an average of 98.2%. The growth rate of the root system of lettuce in the high desalted group increased significantly. A higher degree of desalination can avoid the negative impact of salt stress on the root system of lettuce.

[0111] Table 4 Basic properties of soil

[0112]

[0113] Table 5 The amount of carbon solution, urea, superphosphate, potassium chloride and N / P substitution rate of each treatment

[0114]

[0115] Biomass is an important indicator to prove increased production. Experiments have shown that a higher degree of desalination is beneficial. In the experiment, nitrogen replacement rates ranging from 24% to 40% can achieve increased production. A higher nitrogen utilization rate can be appropriately adopted to increase the land's capacity for charcoal liquid without exceeding the soil's ability to absorb nutrients and salts.

[0116] (4) Field test verification of the desalinated carbon liquid obtained in (1):

[0117] The field in-situ soil column test was conducted in Nanjing Taihe Rice Planting Professional Cooperative. The wheat variety for the test was Ningmai 33. The total growth cycle is from November 2023 to May 2024. The wheat soil column test adopts a planting method of three holes per pot and three plants per hole, which is sowing and planting. The experimental wheat soil column was customized with PVC material, with a diameter of 50cm, an effective height of 50cm, 35cm buried in the soil and 15cm above ground. The nitrogen fertilizer used in the experiment was urea, which was applied three times as base fertilizer, tiller fertilizer and ear fertilizer, and the ratio of the three nitrogen fertilizer applications was 3:3:4 (mass ratio). Phosphorus fertilizer (P2O5) and potassium fertilizer (K2O) were applied once at the base fertilizer. The basic physical and chemical properties of the soil before tillage are shown in Table 6.

[0118] Table 6 Basic physical and chemical properties of soil before tillage

[0119]

[0120] During wheat cultivation, the conventional fertilizer application rate is 240 kgN ha -1、96kg Pha -1 and 192kg Kha -1 In this part of the study, hydrothermal charcoal liquid was used as a fertilizer synergist, and 200 ml was added in the base fertilizer, jointing and booting stage, and ear fertilizer stage, respectively. CM220, CM260, GV220, and GV260 groups had 240 kg N ha -1 、96kg Pha -1 and 192kg K ha -1 The conventional fertilizer application rate was still applied normally. The control treatments were no fertilizer (CK0) and conventional fertilizer (CKU). No additional water management was performed on a daily basis. The test results showed that compared with conventional fertilization, the additional application of hydrothermal charcoal liquid (CM220, CM260, GV220, GV260) acted as a fertilizer synergist and significantly promoted the root development and growth of wheat. Compared with the control group CKU, CM220, CM260, GV220, and GV260 increased the protein content by 6.0%, 3.4%, 1.1%, and 2.3%, respectively; CM220, CM260, GV220, and GV260 increased the crude fat content by 3.3%, 8.1%, and 3.3%, respectively, while GV260 had no improving effect; CM220, CM260, GV220, and GV260 increased the starch content by 5.2%, 6.3%, 3.8%, and 6.6%, respectively; CM220, CM260, GV220, and GV260 increased the yield by 20.8%, 20.4%, 21.7%, and 19.7%, respectively.

[0121] like Fig. 9 As shown in the figure, compared with CKU, the application of charcoal liquid had no significant effect on the growth of wheat at the heading stage, which was reflected in plant height, SPAD value, number of tillers and number of effective ears. There were slight differences in chlorophyll fluorescence images among the treatments, which reflected that photosynthesis was slightly stronger after the application of charcoal liquid than CKU. However, the application of charcoal liquid had a significant effect on dry weight and fresh weight, which increased dry weight and fresh weight significantly.

[0122] like Fig.10 As shown, compared with CKU, application of carbon solution significantly promoted the growth of wheat roots, which was reflected in fresh weight, dry weight, root length, root surface area, root tip and root activity, especially in GV220.

[0123] like Fig.11As shown in the results, compared with CKU, the application of charcoal liquid also promoted the growth of wheat, thereby increasing the yield by 19.7%-21.7%. This was also proven by indicators such as the number of effective ears and the thousand-grain weight of wheat at maturity. The application of charcoal liquid slightly improved the quality of wheat grains. Compared with the control group, CM220, CM260, GV220 and GV260 increased the protein content by 6.0%, 3.4%, 1.1% and 2.3%, respectively; CM220, CM260, GV220 and GV260 increased the crude fat content by 3.3%, 8.1% and 3.3%, respectively, while GV260 had no improving effect; CM220, CM260, GV220 and GV260 increased the starch content by 5.2%, 6.3%, 3.8% and 6.6%, respectively; CM220, CM260, GV220 and GV260 increased the yield by 20.8%, 20.4%, 21.7% and 19.7%, respectively.

[0124] (5) Hydrothermal carbon synthesis

[0125] Hydrothermal carbon was prepared from two typical livestock manures (pig manure and cow manure, marked as PM and CM) from a farm in Jiangsu Province. The pressure in the reactor was 1.5 MPa; the material ratio of manure to water was 1 kg:10 L. During the preparation, 5 kg of manure was placed in a high-pressure hydrothermal reactor, and 50 L of water was used as the solvent and reaction medium, and the reaction was carried out at 180 ° C, 220 ° C, and 260 ° C for 1 h. The obtained manure-derived hydrothermal carbon was dried in an oven at 90 ° C, ground to pass a 2 mm sieve, and stored in a sealed reagent bottle. The pig manure-derived hydrothermal carbons (marked as PCs) prepared at 180 ° C, 220 ° C, and 260 ° C were recorded as PC180, PC220, and PC260, respectively. The cow manure-derived hydrothermal carbons (CCs) prepared at 180 ° C, 220 ° C, and 260 ° C were recorded as CC180, CC220, and CC260, respectively. The basic physical and chemical properties of different feces and their feces-derived hydrochars are shown in Table 7.

[0126] Table 7 Basic physical and chemical properties of different feces and feces-derived hydrothermal charcoal

[0127]

[0128]

[0129] Note: The material ratio of hydrothermal carbonization (HTC) is 1:10, and the residence time is 1 hour. PC180, PC220 and PC260 are hydrothermal carbons of pig manure prepared at 180℃, 220℃ and 260℃ respectively; CC180, CC220 and CC260 are hydrothermal carbons of cow manure prepared at 180℃, 220℃ and 260℃ respectively. The solid-liquid ratio during pH determination is 1:10. Zeta potential is measured at pH=7 with water as dispersant. C, N, H and S are determined by elemental analyzer, O(%)=100%-C%-N%-H%-S%-Ash%. SSA is specific surface area, PV is pore volume, APD is average pore diameter, and carrier gas is nitrogen. ND means no detection.

[0130] (5) The hydrothermal charcoal obtained in (4) was subjected to a soil column test to verify its performance

[0131] The rice soil column test was conducted at the experimental base of Jiangsu Academy of Agricultural Sciences. The test rice variety was Nanjing 46. The seedlings of the rice soil column test were transplanted on June 23, 2021, and the planting method was adopted with three holes per pot and three plants per hole. The nitrogen fertilizer used in the experiment was urea, which was applied three times as base fertilizer, tillering fertilizer and panicle fertilizer. The fertilization time was June 25, July 6 and August 19, 2021, respectively. The ratio of the three nitrogen fertilizer applications was 3:3:4. Phosphorus fertilizer (P2O5) and potassium fertilizer (K2O) were applied once at the base fertilizer. The basic properties of the test soil are as follows: pH = 5.27, organic carbon 17.02g kg -1 , total nitrogen 1.88 g kg -1 , total phosphorus 0.455 g·kg -1 , total potassium 12.4g·kg -1 , available phosphorus 8.2 mg kg -1 , fast-acting potassium 82.6 mg kg -1 , alkaline nitrogen 165.8mg·kg -1 . In this part of the study, the treatments with manure and manure-derived hydrocharcoal reduced nitrogen fertilizer and phosphorus fertilizer by 20% and 30% (mass fraction), respectively, while the control treatment was fertilized normally. Daily water management uses tap water for irrigation, and the water layer on the field surface is maintained at 3-5 cm. The experimental paddy soil columns were customized using PVC material, with a diameter of 30 cm and an effective height of 50 cm. Each soil column was filled with 35 kg of paddy soil, of which the soil from 0 to 20 cm of the paddy soil column was topsoil. When manure and its manure-derived hydrocharcoal (MHCs) were applied, they were mixed with the topsoil at a ratio of 0.5% (i.e., the mass ratio of hydrocharcoal to topsoil was 0.5%) and then loaded into the soil column. No material was applied to the remaining subsoil.

[0132] Soil column experiments show that manure-derived hydrochar has unique properties and rich nutrients. When returned to the field under the coupling of nitrogen and phosphorus fertilizer reduction in paddy fields, it can meet the nutrient needs of rice growth and development, while reducing the risk of soil nitrogen and phosphorus loss and the loss of active gaseous nitrogen. For example, the reduction effect of MHCs on important active gaseous nitrogen (N2O and NH3) in paddy soil is greatly affected by the raw materials. Among them, pig manure hydrochar (PCs) showed a good trend of N2O emission reduction, with a reduction range of 25.0-28.4%; while the soil N2O emission of cow manure hydrochar (CCs) did not change significantly; direct return of manure to the field did not show any emission reduction effect. In addition to the effect of PCs themselves on soil aeration conditions, it reduces the concentration of substrates for denitrification reactions (10.1-66.9% nitrate nitrogen), reduces the activity of nitrate reductase and nitrite reductase, thereby inhibiting the denitrification process and reducing the generation of N2O. Soil NH3 volatilization decreased significantly after the application of manure and its MHCs, with the reduction ranging from 38.7% to 54.5%. Figure 3-6 The effects of different manure and its hydrocharcoal on rice growth and rice yield are shown in Tables 9 and 10.

[0133] The experimental treatments, numbers and fertilizer amounts are shown in Table 8.

[0134] Table 8 Experimental treatment, number and fertilizer application amount

[0135]

[0136] Table 9 Effects of different feces and their hydrocharcoal application on rice growth

[0137]

[0138] Note: Lowercase letters indicate significant differences between the control and feces and MHCs treatments. If there are no identical letters, it means that the differences between the treatments are significant (P<0.05).

[0139] Table 10 Effects of different manure and its hydrocharcoal application on rice yield

[0140]

[0141] The concentration trends of ammonium nitrogen and nitrate nitrogen in field surface water treated with different feces and their MHCs were roughly the same. Figure 3As shown in (a), except for the PK treatment where the ammonium nitrogen concentration in the field surface water was always low, the peak ammonium nitrogen concentration in the field surface water of the other treatments during the three fertilizer periods appeared on the 1st to 2nd day of the fertilizer period. The application of inorganic nitrogen fertilizer in the early stage of basal fertilizer caused the ammonium nitrogen concentration in the field surface water to reach a peak on the 1st to 3rd day of the fertilizer period. Except for the PM and CC180 treatments, the peak ammonium nitrogen concentration in the field surface water of NPK was higher than that of other treatments. As the fertilizer period progressed, the ammonium nitrogen concentration in the field surface water gradually decreased. After the addition of inorganic nitrogen fertilizer during the tillering fertilizer period, the ammonium nitrogen concentration in the field surface water reached a peak on the 1st day of the fertilizer period, and then gradually decreased. Among them, except for PM and PC180, the ammonium nitrogen concentration in the field surface water of NK during the tillering fertilizer period was always higher than that of other treatments. The ammonium nitrogen concentration in the field surface water reached a peak on the 1st to 3rd day of the fertilizer period during the ear fertilizer period, which was lower than the ammonium nitrogen concentration in the field surface water in the first two fertilizer periods. As Figure 3 As shown in (b), the peak nitrate nitrogen concentration of field surface water in the three fertilizer periods generally appeared on the 7th day of the fertilizer period. The nitrate nitrogen concentration of field surface water was low overall during the basal fertilizer period, and the peak nitrate nitrogen concentration of NPK field surface water was the largest. The nitrate nitrogen concentration of field surface water in CM and NPK treatments during the tillering fertilizer period was higher than that of other treatments, and the peak values ​​of CM and NPK treatments appeared on the 5th and 7th days of the fertilizer period, respectively. The nitrate nitrogen concentration of field surface water increased further during the ear fertilizer period, and the nitrate nitrogen concentration of field surface water in CC180 treatment was higher than that of other treatments, with a peak value on the 7th day of the fertilizer period.

[0142] like Figure 4 As shown in the figure, the trends of the phosphorus concentration changes in the field water treated with different feces and their MHCs were roughly the same, and the PM treatment showed a higher concentration of phosphorus in the field water. The peak values ​​of the phosphorus concentration in the field water in the three fertilizer periods of each treatment appeared on the first day of the fertilizer period, and the phosphorus content in the field water gradually decreased as the fertilizer period progressed. Among them, the peak values ​​of the phosphorus concentration in the field water of PK and NPK treatments were the highest in the early stage of basal fertilizer, and then decreased rapidly. The phosphorus concentration in the field water of PM treatment in the late stage of basal fertilizer remained at a high level; the phosphorus concentration in the field water of each treatment in the tillering fertilizer period was significantly lower than that in the basal fertilizer period. In addition, the phosphorus concentration in the field water of PM treatment was higher than that in other treatments; after two months of rice growth, most of the phosphorus in the field water in the system was absorbed and utilized by the plants, so the phosphorus concentration in the field water of the ear fertilizer treatment was always low, and there was no significant difference between the treatments.

[0143] like Figure 5 As shown in Figure 2, after the application of different manures and their MHCs, the soil N2O emission fluxes of each treatment in the paddy field were as follows: Figure 5 As shown. The overall trends of N2O emission fluxes in different treatments were similar. The soil was always flooded during the basal fertilizer period and the tillering fertilizer period, and the soil N2O emission flux was low. As the fertilizer period progressed, the soil water layer in the paddy field gradually decreased during the baking period, and the soil N2O emission flux gradually increased, reaching the emission peak on the 40th day after rice transplanting, and then gradually decreased. The N2O emission flux was at a low level during the panicle fertilizer period, and was generally at a low level afterwards.

[0144] By calculating the cumulative N2O emissions from soil during the rice growth period, it can be seen that the N2O emission reduction trend of MHCs may be better than that of manure treatment, but the influence of different raw materials varies greatly. The effects of applying different manure and their MHCs on the cumulative N2O emissions from soil vary. Compared with NPK, the cumulative N2O emissions from soil after PM application showed an increasing trend, from 30.24 mg·m -2 Increased to 32.42 mg·m -2 , increased by 7.2%, and the increasing trend was not significant (P>0.05); however, the application of PCs showed an inhibitory effect on soil N2O emissions, with the cumulative soil N2O emissions of PC180 and PC260 decreasing to 22.67 mg·m -2 and 21.64 mg·m -2 , which significantly decreased by 25.0% and 28.4% (P<0.05). However, the application of CM and CCs promoted soil N2O emissions, with CM, CC180 and CC260 increasing to 33.64 mg·m -2 、34.30mg·m -2 and 35.99 mg·m -2 , increased the cumulative soil N2O emissions by 11.3%, 13.4% and 19.0%, but the changes were not significant (P>0.05). Manure treatment had no significant effect on soil N2O emissions, different MHCs had inconsistent effects on soil N2O emissions, CCs had no significant effect on N2O emissions, and PCs treatment had a better N2O emission reduction effect.

[0145] like Figure 6 As shown in the figure, NH3 volatilization from paddy soil is another way of loss of active gaseous nitrogen in the soil, and the effects of different feces and their MHCs on it are shown in the figure. Figure 6 It can be seen that soil NH3 volatilization is mainly concentrated in the basal fertilizer period and the tillering fertilizer period. The soil NH3 volatilization flux in the ear fertilizer period is lower than that in the first two fertilizer periods. Compared with NPK, the soil NH3 volatilization of feces and its MHCs showed a significant downward trend. The peak of soil NH3 volatilization flux in the basal fertilizer period occurred on the 2nd to 4th day, among which the soil NH3 volatilization flux of NPK was significantly higher than that of other treatments, and the peak appeared on the 2nd day, which was 16.43 kg·hm -2 ·d -1 The peak of soil NH3 volatilization flux during tillering period occurred on the 1st to 3rd day. Similarly, the soil NH3 volatilization flux of NPK was significantly higher than that of other treatments. Its NH3 volatilization flux peak occurred on the 1st day, which was 14.62 kg·hm -2 ·d -1 The soil NH3 volatilization flux was generally low during the ear fertility period, and the emission peak occurred on the 2nd to 3rd day. Among them, the soil NH3 volatilization flux peak of PC180 was the highest, which was 5.44 kg·hm-2 ·d -1 From the perspective of soil NH3 volatilization flux, the manure and its MHCs treatments have shown a significant reduction trend in the basal fertilizer stage and tillering fertilizer stage.

[0146] The calculation of the soil NH3 volatilization accumulation in each treatment during the three fertilizer periods showed that the soil NH3 volatilization accumulation showed a significant decreasing trend after the application of different manures and their MHCs (P<0.05). Compared with NPK, PM, PC180 and PC260 increased from 152.31 kg·hm -2 ·d -1 and 71.39 kg·hm -2 、83.82kg·hm -2 and 78.53 kg·hm -2 , decreased by 53.1%, 45.3% and 48.4% respectively. The soil NH3 volatilization accumulation of PM was less than that of PCs, but there was no significant difference (P>0.05). However, CM, CC180 and CC260 decreased to 85.15 kg·hm -2 , 93.37kg·hm -2 and 69.28 kg·hm -2 , reducing the soil NH3 volatilization accumulation by 44.1%, 38.7% and 54.5% respectively. The soil NH3 emission reduction effect of CM was better than that of CC180 and worse than that of CC260. There was no significant difference between CM treatment and CCs treatment (P>0.05). The accumulated volatilization showed that the basal fertilizer period and tillering fertilizer period were the main periods for soil NH3 emission reduction in the treatment of manure and its MHCs.

[0147] The above embodiments are only used to illustrate the technical solutions of the present invention. Those skilled in the art should understand that the above embodiments do not limit the present invention in any form, and any technical solutions obtained by equivalent replacement or equivalent transformation shall fall within the protection scope of the present invention.

Claims

1. A mobile photovoltaic-powered subcritical fertilizer production system for nitrogen and phosphorus emission reduction and efficiency improvement and high-humidity waste resource disposal, characterized in that: It includes a solar preheating system, a photovoltaic power supply system, an auxiliary heating system, a hydrothermal reaction system and a post-processing system. The photovoltaic power supply system and the auxiliary heating system are connected to the electric load of the hydrothermal reaction system; the hydrothermal reaction system is connected to the solar preheating system and the post-processing system respectively; The solar preheating system comprises a heat pipe solar collector (9), a solar water tank (8), a PLC controller (7), a water pump (10) and a stop valve (11); one side of the solar water tank (8) is connected to the hydrothermal reaction system via the water pump (10) and the stop valve (11), and the other side is connected to the PLC controller (7) via a pipeline; the solar water tank (8) and the heat pipe solar collector (9) are connected in parallel and fixed by a bracket; The photovoltaic power supply system comprises a photovoltaic module (1), a photovoltaic controller (2), a battery pack (3), an inverter (4) and a distribution box (5); the output end of the photovoltaic module (1) is connected to the input end of the photovoltaic controller (2); the output end of the photovoltaic controller (2) is connected to the input end of the battery pack (3); the output end of the battery pack (3) is connected to the input end of the inverter (4); the output end of the inverter (4) is connected to the input end of the distribution box (5); and the output end of the distribution box (5) is connected to the electrical load of the hydrothermal reaction system; The auxiliary heating system comprises an auxiliary heater (6); the output end of the auxiliary heater (6) is connected to an electrical load of the hydrothermal reaction system; The hydrothermal reaction system comprises a feeder (12), a reactor (13), a filter press (14), a solid storage device (15) and a liquid storage device (16); the feeder (12) is connected to a feed port (17) of the reactor (13); a discharge port (20) of the reactor (13) is connected to the filter press (14); the filter press (14) is respectively connected to the solid storage device (15) and the liquid storage device (16); the liquid storage device (16) is connected to the electrodialysis device (21); The post-treatment system comprises an electrodialysis device (21); the inlet of the electrodialysis device (21) is connected to the outlet of the liquid storage device (16).

2. According to claim 1, a mobile photovoltaic-powered subcritical fertilizer production system for nitrogen and phosphorus emission reduction and efficiency improvement and high-humidity waste resource disposal is characterized in that: The solar water tank (8) in the solar preheating system is connected to the heat pipe solar collector (9), the inner wall of the heat pipe solar collector (9) is provided with a temperature sensor and is connected to the PLC controller (7); The bottom of the heat pipe solar collector (9) is fixed by a bracket; The solar water tank (8) is provided with a water inlet at one end and a water outlet at the other end, and a stop valve.

3. The mobile photovoltaic-powered subcritical fertilizer production system for nitrogen and phosphorus emission reduction and efficiency improvement and high-humidity waste resource disposal according to claim 1 is characterized in that: The photovoltaic components (1) in the photovoltaic power supply system are at least one group and are provided with a base. The battery group (3) in the photovoltaic power supply system comprises at least two batteries, and the batteries are connected in series.

4. A mobile photovoltaic-powered subcritical fertilizer production system for nitrogen and phosphorus emission reduction and efficiency improvement and high-humidity waste resource disposal according to claim 1, characterized in that: The feeder (12) has a sample adding port on the top and a sample outlet on the side, and the sample outlet of the feeder (12) is connected to the feed port (17) of the reaction kettle (13); The reaction kettle (13) comprises a motor (18) and a stirrer (19); The inlet of the filter press (14) is connected to the discharge port (20) of the reaction kettle (13), and is provided with a water pump (10) and a stop valve (11); The outlet of the filter press (14) is in communication with a solid storage device (15) and a liquid storage device (16); The product storage device used in the hydrothermal reaction stage includes a solid storage device (15) and a liquid storage device (16).

5. The mobile photovoltaic-powered subcritical fertilizer production system for nitrogen and phosphorus emission reduction and efficiency improvement and high-humidity waste resource disposal according to claim 1 is characterized in that: The outlet of the liquid storage device (16) is connected to the inlet of the electrodialysis device (21) by a pipeline.

6. An application of a mobile photovoltaic-powered subcritical fertilizer production system for nitrogen and phosphorus emission reduction and efficiency improvement and high-humidity waste resource disposal, characterized in that: The steps include: In the solar water tank (8), water required for the hydrothermal carbonization reaction is preheated. The process is monitored and controlled by the PLC controller (7). After the temperature is raised, the water is transported to the reactor (13) through the water pump (10) and the stop valve (11); The raw materials for the hydrothermal carbonization reaction are added from the inlet of the feeder (12) and then transported from the outlet of the feeder (12) to the feed port (17) of the reactor (13); the raw materials for the hydrothermal carbonization reaction are high-humidity biomass, the reaction temperature is 180-260° C., the reaction time is 1-2 hours, the mass volume ratio of feces or tail vegetables to water in the hydrothermal carbonization reaction is 1kg:9-11L, and the feces are cow dung or pig dung; the speed of the stirrer (19) in the reactor (13) is 200-300r / min, and it is used for stirring the raw materials during the hydrothermal carbonization process; The reactor (13) is completely closed during the hydrothermal carbonization process, and the pressure in the reactor (13) is 1.0-1.8 MPa. After the reaction is completed, the reactor (13) is cooled; after the pressure of the reactor (13) is released, the reactor can be opened to discharge the material; the product is passed from the discharge port (20) of the reactor (13) to the filter press (14) with the help of a water pump (10) and a stop valve (11), and the solid-liquid separation of the product is performed by a filter press method, so that the water content of the hydrothermal carbon is less than 30%, the hydrothermal carbon is stored in a solid storage device (15), and the carbon liquid is stored in a liquid storage device (16); The carbon liquid enters the electrodialysis device (21) from the liquid storage device (16) and is electrodialyzed under the conditions of DC voltage 25-35V and 40-80RPM. The desalination rate is 45%-90%, and the electrodialysis time is 15-120min, to obtain a desalinated carbon liquid with a conductivity of 1.40-6.75mS / cm.

7. The application of a mobile photovoltaic-powered subcritical fertilizer production system for nitrogen and phosphorus emission reduction and efficiency improvement and high-humidity waste resource disposal according to claim 6 is characterized in that: The desalination rate of the carbon liquid is 80%-90%, and the desalted carbon liquid with an electrical conductivity of 1.40±0.15mS / cm is obtained.

8. The application of a mobile photovoltaic-powered subcritical fertilizer production system for nitrogen and phosphorus emission reduction and efficiency improvement and high-humidity waste resource disposal according to claim 6 is characterized in that: Desalinated charcoal liquid is applied as fertilizer to the soil for plant growth, and the nitrogen replacement rate of desalinated charcoal liquid is 24%-40%; for fast-growing plants, desalinated charcoal liquid is applied twice; the first time is applied in the seedling stage of the plant, and the second time is applied in the middle and late stages of plant growth. The mass ratio of the desalinated charcoal liquid applied for the first time to the desalinated charcoal liquid applied for the second time is 2:2.5-3.5; for wheat, desalinated charcoal liquid is applied three times, and the application amount of desalinated charcoal liquid in the base fertilizer, tillering fertilizer and ear fertilizer stages is equivalent.

9. The application of a mobile photovoltaic-powered subcritical fertilizer production system for nitrogen and phosphorus emission reduction and efficiency improvement and high-humidity waste resource disposal according to claim 6, characterized in that: Hydrochar is applied as fertilizer to soil for plant growth, the nitrogen replacement rate of hydrochar is 15%-25%, the phosphate fertilizer replacement rate of hydrochar is 25%-35%, the percentages are mass fractions, and the hydrochar is manure-derived hydrochar; the application amount of hydrochar is equivalent in the base fertilizer, tillering fertilizer, and ear fertilizer stages; when applying, the hydrochar is fully mixed with the surface soil of 0-20 cm, and the application amount of hydrochar is 0.2-2% of the surface soil, and % is the mass fraction.

10. The application of a mobile photovoltaic-powered subcritical fertilizer production system for nitrogen and phosphorus emission reduction and efficiency improvement and high-humidity waste resource disposal according to claim 8, characterized in that: When desalinated carbon liquid is applied as fertilizer to the soil for plant growth, it increases the chlorophyll content of plant leaves, promotes the accumulation of plant biomass, and increases the length of plant roots.

Images