CN104478519B - The device and method of nitrogen phosphorus is reclaimed with the supercritical water gasification product of blue-green algae algae solution - Google Patents

Abstract

The invention relates to a device and a method for recovering nitrogen and phosphorus from a supercritical water gasification product of cyanobacteria liquid, belonging to the field of resources and environment. The invention utilizes the characteristics of supercritical water to directly gasify the cyanobacteria liquid salvaged ashore, recover a large amount of ammonia nitrogen and active phosphorus components in the algae liquid enriched in the liquid phase product, and generate MAP crystals to be used as crop fertilizers, solving the problem of In the traditional treatment process of cyanobacteria, there are problems such as high dehydration energy consumption, long treatment cycle, and low level of resource utilization, etc., and effective recovery of cyanobacteria can be achieved after rapid treatment. The method provided by the present invention realizes two "synchronous recovery", synchronous recovery of nitrogen and phosphorus in cyanobacteria, and synchronous recovery of P element in supercritical water gasification liquid phase and solid phase, because P element mostly exists in solid phase residue , through the transformation of the P form in the solid phase residue into the liquid phase, and then a high nitrogen and phosphorus recovery efficiency of about 90% can be obtained.

Description

Device and method for recovering nitrogen and phosphorus from supercritical water gasification product of cyanobacteria liquid

technical field

The invention belongs to the field of resources and environment, and in particular relates to a device and a method for recovering nitrogen and phosphorus from a supercritical water gasification product of cyanobacteria liquid.

Background technique

The eutrophication of water body and the outbreak of cyanobacteria to form algal blooms have caused serious harm to the environment of our country. Salvage is an important and common measure to eliminate algae bloom pollution in inland water bodies, and it has been widely used in Dianchi Lake, Taihu Lake, and Chaohu Lake in my country. According to incomplete statistics, Jiangsu Province salvaged 970,000 tons of algae liquid from Taihu Lake in 2011, nearly 300,000 tons more than in 2010. How to timely and quickly harmlessly treat and utilize these salvaged algae fluids is the key to the control of algal blooms. If the salvaged algae liquid cannot be treated in a timely and effective manner, after the algae liquid rots and stinks, nutrients such as nitrogen and phosphorus will be released into the water body and cause secondary environmental pollution, resulting in continuous outbreaks of cyanobacteria in lakes.

At present, the Chinese patent application No. 200710025550.9 discloses a method for preparing fertilizers from water bloom cyanobacteria. The patent dehydrates the dehydrated cyanobacteria in a composting manner to make organic fertilizer or organic-inorganic compound fertilizer, but dehydration is required. The water content of cyanobacteria reaches 20-40%, and the processing time is long, which requires a lot of energy and space; the Chinese patent application number 20061009.5 discloses a method and product of cyanobacteria biogas energy fermentation, which proposes The anaerobic fermentation method is used to treat the salvaged cyanobacteria and then obtain biogas, but the problems such as long processing time and low efficiency cannot be changed; the Chinese patent application number 201010520895.3 discloses a system and method for treating cyanobacteria using supercritical water oxidation. By treating cyanobacteria with supercritical water oxidation, and finally forming CO ₂ and H ₂ O, the harmless treatment of cyanobacteria is realized; and this patent uses supercritical water partial oxidation water gasification technology to remove nitrogen and phosphorus in algae liquid Transform into liquid phase products, and then use the MAP method to efficiently recover nitrogen and phosphorus in the algae liquid, and break through the limitation that the MAP method is only suitable for liquid phase recovery, and recover a large amount of P elements in the solid phase residual material through acid washing and shaking conversion.

Contents of the invention

Technical problem to be solved: the purpose of this invention is to overcome the deficiencies in the prior art and provide a device and method for recovering nitrogen and phosphorus from the supercritical water gasification product of cyanobacteria liquid, and use the characteristics of supercritical water to salvage the cyanobacteria ashore. After the algae liquid is directly gasified, a large amount of ammonia nitrogen and active phosphorus components in the enriched algae liquid in the liquid phase product are recovered, and MAP crystals (also known as struvite) are generated and used as crop fertilizers to solve dehydration in the traditional treatment process of cyanobacteria High energy consumption, long processing cycle, low level of resource utilization, etc., to achieve effective recycling of blue-green algae after rapid processing.

Technical scheme of the present invention:

The cyanobacteria liquid salvaged during the lake bloom contains a large amount of nitrogen and phosphorus elements, which is a good resource. In the invention, the supercritical water gasification process is performed on the algae liquid, and most of the nitrogen and phosphorus are transferred to the liquid phase product, and then the MAP crystal is generated by the MAP method for efficient recycling.

A device for recovering nitrogen and phosphorus from supercritical water gasification products of cyanobacteria liquid, including storage tanks, inlet valves, high-pressure plunger pumps, outlet valves, heat exchangers, gas-liquid flow valves, gas-liquid separator tanks, wet gas flow meter, liquid flow meter, back pressure valve, supercritical reactor, MAP reaction tank, low-speed stirring motor M, magnesium chloride storage tank, potassium dihydrogen phosphate storage tank, system pressure regulating valve, magnesium chloride control valve, potassium dihydrogen phosphate control valve , Magnesium chloride quantitative feeder D, potassium dihydrogen phosphate quantitative feeder D, drying room, pH online monitor, regulation pool, MAP crystal delivery valve, solid-phase oscillator, acid storage tank, acid control valve, Acid liquid quantitative meter D, acid liquid output valve; wherein, the first output pipe of the storage tank is connected with the first input pipe of the heat exchanger through the inlet valve, high-pressure plunger pump, and outlet valve in sequence, and the first output pipe of the heat exchanger The pipe is connected with the input pipe of the supercritical reactor through the back pressure valve, the first output pipe of the supercritical reactor is connected with the second input pipe of the heat exchanger through the system pressure regulating valve, and the second output pipe of the supercritical reactor is passed through The control valve is connected with the first input pipe of the solid-phase oscillator, the acid liquid storage tank is connected with the second input pipe of the solid-phase oscillator through the acid liquid control valve and the acid quantitative meter D successively, and the first output pipe of the solid-phase oscillator is The tube is connected to the input tube of the supercritical reactor through the acid liquid output valve, and the second output tube of the solid phase oscillator outputs the solid phase product;

The second output pipe of the heat exchanger is connected to the input pipe of the gas-liquid separator tank through the gas-liquid flow valve, and the first output pipe of the gas-liquid separator tank is connected to the first input pipe of the drying room through a wet gas flow meter. The second output pipe of the gas-liquid separator tank is connected to the input pipe of the MAP reaction tank through the liquid flow meter, and the magnesium chloride storage tank is connected to the input pipe of the MAP reaction tank through the magnesium chloride control valve and the magnesium chloride quantitative feeder D in turn, and the dihydrogen phosphate The potassium storage tank is connected to the input pipe of the MAP reaction tank through the potassium dihydrogen phosphate control valve and the potassium dihydrogen phosphate quantitative feeder D in sequence, and the first output pipe of the MAP reaction tank is connected to the second one of the drying room through the MAP crystal delivery valve. The input pipes are connected, the first output pipe of the drying room outputs the gas phase product, the second output pipe outputs the finished fertilizer, the second output pipe of the MAP reaction tank outputs the supernatant, and the pH on-line monitor is connected in parallel with the control tank and passes through the pipeline Insert it into the MAP reaction tank, and place the fan blade of the low-speed stirring motor M in the MAP reaction tank.

The method for reclaiming nitrogen and phosphorus in the water bloom cyanobacteria liquid by means of a device for recovering nitrogen and phosphorus from the supercritical water gasification product of the cyanobacteria liquid comprises the following steps:

1) Put the salvaged cyanobacteria liquid into the supercritical reactor through the high-pressure plunger pump 3, stay for 3-5 minutes for water gasification reaction; the product recovers heat through the heat exchanger, and the recovered heat is used for the next batch Preheating treatment of cyanobacteria sampling; after cooling and reducing the pressure of the product passing through the heat exchanger, it enters the gas-liquid separator tank to separate the gas-liquid product, and obtains the liquid phase product rich in nitrogen and phosphorus; the solid phase product is adjusted by the control valve After entering the solid phase oscillator through the second output pipe of the supercritical reactor 11, the acid liquid in the acid liquid storage tank enters the solid phase oscillator quantitatively through the acid liquid control valve and the acid liquid quantitative meter D, and the supernatant after shaking for 8 hours Enter the MAP reaction tank;

2) The supercritical liquid phase product enters the MAP reaction tank through the delivery pipeline for reaction, and monitors and regulates the acid-base environment in the MAP reaction tank through the pH online monitor and the regulating pool filled with lye;

3) The magnesium chloride and potassium dihydrogen phosphate dry powder are transported into the MAP reaction tank through the magnesium chloride quantitative feeder D and the potassium dihydrogen phosphate quantitative feeder D respectively, and are stirred and dissolved by the low-speed stirring motor M to participate in the MAP reaction;

4) After the reaction, the supernatant is discharged through the second output pipe of the MAP reaction tank, and is subjected to post-treatment, and the generated MAP crystal precipitation enters the drying room through the first output pipe of the MAP reaction tank through the second input pipe of the drying room. During the period, after the waste heat in the gas phase product produced by supercritical water gasification is dried, the gas phase product is output through the first output pipe of the drying room, and the finished fertilizer is output through the second output pipe of the drying room and collected as agricultural fertilizer for application .

The method for recovering nitrogen and phosphorus in the water bloom cyanobacteria liquid by using the device for recovering nitrogen and phosphorus from the supercritical water gasification product of the cyanobacteria liquid, wherein, the pressure of the high-pressure plunger pump in step 1) is set to 22MPa.

The method for recovering nitrogen and phosphorus in the water bloom cyanobacteria liquid with a device for recovering nitrogen and phosphorus from the supercritical water gasification product of the cyanobacteria liquid, wherein, in step 1), the temperature of the supercritical reactor is raised to 450-500° C. in advance.

The method for recovering nitrogen and phosphorus in the water bloom cyanobacteria liquid by using the device for recovering nitrogen and phosphorus from the supercritical water gasification product of the cyanobacteria liquid, wherein, the pH in the MAP reaction tank in step 2) is 9.0-10.7.

The above-mentioned method for reclaiming nitrogen and phosphorus in the water bloom cyanobacteria liquid with the device for recovering nitrogen and phosphorus from the supercritical water gasification product of the cyanobacteria liquid, wherein, the acid liquid stored in the acid liquid storage tank is hydrochloric acid, and the solid phase The oscillator adopts the sequential batch mode of operation.

Beneficial effect

First, in the present invention, after the salvaged cyanobacteria liquid rich in nitrogen and phosphorus is directly subjected to supercritical water gasification treatment, a large amount of nitrogen and phosphorus enters the liquid phase product after the reaction, and the nitrogen and phosphorus in the liquid phase are converted into Solid fertilizer, which improves fertilizer efficiency and facilitates subsequent transportation and application;

Second, the entire reaction process of the present invention does not require additional costs caused by secondary dehydration and moisture adjustment, and no additional oxidant is added during the reaction process;

Third, the present invention recovers nitrogen and phosphorus by the MAP method after supercritical water gasification treatment, which can greatly shorten the reaction time and realize efficient and rapid cyanobacteria treatment;

Fourth, the method provided by the present invention realizes two "synchronous recovery", synchronous recovery of nitrogen and phosphorus in cyanobacteria, and synchronous recovery of P element in supercritical water gasification liquid phase and solid phase, because P element mostly occurs in solid In the phase residue, the present invention overcomes the deficiency that the conventional recovery method can only recover nitrogen and phosphorus elements in the liquid phase, and can obtain a high nitrogen and phosphorus recovery efficiency of about 90% through the conversion of the P form in the solid phase residue into the liquid phase.

Description of drawings

Fig. 1 is the schematic diagram of the device for recovering nitrogen and phosphorus in the algae liquid of water bloom cyanobacteria of the present invention, wherein 1 is a storage tank, 2 is an inlet valve, 3 is a high-pressure plunger pump, 4 is an outlet valve, 5 is a heat exchanger, and 6 is a gas pump. Liquid flow valve, 7 is gas-liquid separator tank, 8 is wet gas flow meter, 9 is liquid flow meter, 10 is back pressure valve, 11 is supercritical reactor, 12 is MAP reaction tank, 13 is low-speed stirring motor M , 14 is magnesium chloride storage tank, 15 is potassium dihydrogen phosphate storage tank, 16 is system pressure regulating valve, 17 is magnesium chloride control valve, 18 is potassium dihydrogen phosphate control valve, 19 is magnesium chloride quantitative feeder D, 20 is phosphoric acid Dihydropotassium quantitative feeder D, 21 is the drying room, 22 is the pH online monitor, 23 is the control tank, 24 is the MAP crystal delivery valve, 25 is the solid phase oscillator, 26 is the acid storage tank, 27 is Acid liquid control valve, 28 is an acid liquid quantitative meter D, 29 is an acid liquid output valve, and 30 is a control valve.

detailed description

The present invention will be further described in detail through specific examples below, wherein the solid-phase oscillator 25 adopts a sequential batch operation mode.

Example 1

In conjunction with Figure 1, the device for recovering nitrogen and phosphorus with the supercritical water gasification product of cyanobacteria liquid includes a storage tank 1, an inlet valve 2, a high-pressure plunger pump 3, an outlet valve 4, a heat exchanger 5, and a gas-liquid flow valve 6 , gas-liquid separator tank 7, wet gas flow meter 8, liquid flow meter 9, back pressure valve 10, supercritical reactor 11, MAP reaction tank 12, low-speed stirring motor M13, magnesium chloride storage tank 14, potassium dihydrogen phosphate storage Tank 15, system pressure regulating valve 16, magnesium chloride control valve 17, potassium dihydrogen phosphate control valve 18, magnesium chloride quantitative feeder D19, potassium dihydrogen phosphate quantitative feeder D20, drying room 21, pH online monitor 22, Control tank 23, MAP crystal transfer valve 24, solid-phase oscillator 25, acid liquid storage tank 26, acid liquid control valve 27, acid liquid quantitative meter D28, acid liquid output valve 29; wherein, the first output pipe of storage tank 1 The inlet valve 2, the high-pressure plunger pump 3, and the outlet valve 4 are connected to the first input pipe of the heat exchanger 5 in sequence, and the first output pipe of the heat exchanger 5 is connected to the input pipe of the supercritical reactor 11 through the back pressure valve 10. Connect, the first outlet pipe of supercritical reactor 11 is connected with the second inlet pipe of heat exchanger 5 by system pressure regulating valve 16, the second outlet pipe of supercritical reactor 11 is connected with solid phase oscillator 25 by control valve 30 The acid liquid storage tank 26 is connected to the second input pipe of the solid-phase oscillator 25 through the acid liquid control valve 27 and the acid liquid quantitative meter D28 successively, and the first output pipe of the solid-phase oscillator 25 passes through the acid liquid. The liquid output valve 29 is connected with the input pipe of the supercritical reactor 11, and the second output pipe of the solid phase oscillator 25 outputs the solid phase product;

The second output pipe of the heat exchanger 5 is connected to the input pipe of the gas-liquid separator tank 7 through the gas-liquid flow valve 6, and the first output pipe of the gas-liquid separator tank 7 passes through the connection between the wet gas flow meter 8 and the drying room 21. The first input pipe is connected, and the second output pipe of gas-liquid separator tank 7 is connected with the input pipe of MAP reaction tank 12 by liquid flowmeter 9, and magnesium chloride storage tank 14 passes through magnesium chloride control valve 17, magnesium chloride quantitative feeder D19 and The input pipe of MAP reaction tank 12 links to each other, potassium dihydrogen phosphate storage tank 15 links to each other with the input pipe of MAP reaction tank 12 successively by potassium dihydrogen phosphate control valve 18, potassium dihydrogen phosphate quantitative feeder D20, the MAP reaction tank 12 The first output pipe is connected with the second input pipe of the drying room 21 through the MAP crystal transfer valve 24, the first output pipe of the drying room 21 outputs the gas phase product, the second output pipe outputs the finished fertilizer, and the second output pipe of the MAP reaction tank 12 The output pipe outputs the supernatant, and the online pH monitor 22 is connected in parallel with the regulating tank 23 and inserted into the MAP reaction tank 12 through the pipeline, and the fan blade of the low-speed stirring motor M13 is placed in the MAP reaction tank 12 .

Example 2

The method for recovering nitrogen and phosphorus in the water bloom cyanobacteria liquid by means of a device for recovering nitrogen and phosphorus from the supercritical water gasification product of the cyanobacteria liquid comprises the following steps:

1) The salvaged cyanobacteria algae liquid (with a water content of 98% to 99%) enters the storage tank 1, and the algae water is separated to be treated.

2) When the test starts, open the inlet valve 2 of the high-pressure plunger pump, turn on the high-pressure plunger pump 3, and turn on the heating device of the heat exchanger 5 to make its temperature rise to about 300 ° C, open the supercritical reactor 11, and heat up to 500°C.

3) Open the algae liquid outlet valve 4, so that the algae liquid after the separation of the algae water enters the heat exchanger 5, and heats up to 250 ° C through the heat exchanger; then enters the supercritical reactor 11 through the back pressure valve 10, and the When the temperature reaches 400°C and the pressure is 25Mpa, it reaches a supercritical state, and stays for 3 minutes to carry out the water gasification reaction; after the reaction, open the system pressure regulating valve 16, so that the gas-liquid mixed phase product enters the heat exchanger 5, through which the The algae liquid to be treated in the next stage is heated to 250°C, and the temperature of the gas-liquid mixed phase product is lowered during the process, and the gas-liquid flow valve 6 is opened to enter the gas-liquid separator tank 7. After gas-liquid separation, combustible gas and nitrogen-rich The liquid phase product of phosphorus is passed through the wet gas flow meter 8, and the gas phase product with waste heat is used to dry the subsequent obtained fertilizer in the drying room 21 to make a finished product.

4) After the supercritical reaction ends, the inorganic solid phase product is discharged into the solid phase oscillator 25 by the bottom of the supercritical reactor 11, the acid liquid control valve 27 is opened, and the hydrochloric acid solution is quantitatively input by the acid liquid quantitative meter D28, and after the shock stays for 8 hours, Open the acid liquid output valve 29 to allow the supernatant liquid to enter the MAP reaction tank 12 for mixed reaction, and the solid phase product residue in the solid phase oscillator 25 is regularly cleaned and discharged.

5) The liquid phase product enters the MAP reaction tank 12 through the liquid flow meter 9, monitors and adjusts the acid-base environment in the MAP reaction tank 12 through the pH online monitor 22 and the regulating pool 23 filled with lye, and maintains the pH in the MAP reaction tank is 9.0; magnesium chloride and potassium dihydrogen phosphate dry powder are transported into the MAP reaction tank 12 through the magnesium chloride quantitative feeder D19 and the potassium dihydrogen phosphate quantitative feeder D20 respectively, and are stirred and dissolved by the low-speed stirring motor M13 to participate in the MAP reaction.

Example 3

The method for recovering nitrogen and phosphorus in the water bloom cyanobacteria liquid by means of a device for recovering nitrogen and phosphorus from the supercritical water gasification product of the cyanobacteria liquid comprises the following steps:

1) The salvaged cyanobacteria algae liquid (with a water content of 98% to 99%) enters the storage tank 1, and the algae water is separated to be treated.

2) When the test starts, open the inlet valve 2 of the high-pressure plunger pump, turn on the high-pressure plunger pump 3, and turn on the heating device of the heat exchanger 5 to make its temperature rise to about 300 ° C, open the supercritical reactor 11, and heat up to 500°C.

3) Open the algae liquid outlet valve 4, so that the algae liquid after the separation of the algae water enters the heat exchanger 5, and heats up to 250 ° C through the heat exchanger; then enters the supercritical reactor 11 through the back pressure valve 10, and the When the temperature reaches 500°C and the pressure is 22Mpa, it reaches a supercritical state, and stays for 5 minutes for water gasification reaction; after the reaction is completed, open the system pressure regulating valve 16, so that the gas-liquid mixed phase product enters the heat exchanger 5, and through the heat exchanger The algae liquid to be treated in the next stage is heated to 250°C, and the temperature of the gas-liquid mixed phase product is lowered during the process, and the gas-liquid flow valve 6 is opened to enter the gas-liquid separator tank 7. After gas-liquid separation, combustible gas and nitrogen-rich The liquid phase product of phosphorus is passed through the wet gas flow meter 8, and the gas phase product with waste heat is used to dry the subsequent obtained fertilizer in the drying room 21 to make a finished product.

4) After the supercritical reaction ends, the inorganic solid phase product is discharged into the solid phase oscillator 25 by the bottom of the supercritical reactor 11, the acid liquid control valve 27 is opened, and the hydrochloric acid solution is quantitatively input by the acid liquid quantitative meter D 28, and after the shock stays for 8 hours , open the acid liquid output valve 29, so that the supernatant liquid enters the MAP reaction tank 12 for mixed reaction, and the solid phase product residue in the solid phase oscillator 25 is regularly cleaned and discharged.

5) The liquid phase product enters the MAP reaction tank 12 through the liquid flow meter 9, monitors and adjusts the acid-base environment in the MAP reaction tank 12 through the pH online monitor 22 and the regulating pool 23 filled with lye, and maintains the pH in the MAP reaction tank is 10.7; magnesium chloride and potassium dihydrogen phosphate dry powder are transported into the MAP reaction tank 12 through the magnesium chloride quantitative feeder D19 and the potassium dihydrogen phosphate quantitative feeder D20 respectively, and are stirred and dissolved by the low-speed stirring motor M13 to participate in the MAP reaction.

Example 4

The method for recovering nitrogen and phosphorus in the water bloom cyanobacteria liquid by means of a device for recovering nitrogen and phosphorus from the supercritical water gasification product of the cyanobacteria liquid comprises the following steps:

1) The salvaged cyanobacteria algae liquid (with a water content of 98% to 99%) enters the storage tank 1, and the algae water is separated to be treated.

2) When the test starts, open the inlet valve 2 of the high-pressure plunger pump, turn on the high-pressure plunger pump 3, and turn on the heating device of the heat exchanger 5 to make its temperature rise to about 300 ° C, open the supercritical reactor 11, and heat up to 500°C.

3) Open the algae liquid outlet valve 4, so that the algae liquid after the separation of the algae water enters the heat exchanger 5, and heats up to 250 ° C through the heat exchanger; then enters the supercritical reactor 11 through the back pressure valve 10, and the The temperature reaches 450°C, the pressure is 22Mpa, and reaches a supercritical state, and stays for 5 minutes for water gasification reaction; after the reaction is completed, open the system pressure regulating valve 16, so that the gas-liquid mixed phase product enters the heat exchanger 5, and through the heat exchanger The algae liquid to be treated in the next stage is heated to 250°C, and the temperature of the gas-liquid mixed phase product is lowered during the process, and the gas-liquid flow valve 6 is opened to enter the gas-liquid separator tank 7. After gas-liquid separation, combustible gas and nitrogen-rich The liquid phase product of phosphorus is passed through the wet gas flow meter 8, and the gas phase product with waste heat is used to dry the subsequent obtained fertilizer in the drying room 21 to make a finished product.

4) After the supercritical reaction ends, the inorganic solid phase product is discharged into the solid phase oscillator 25 by the bottom of the supercritical reactor 11, the acid liquid control valve 27 is opened, and the hydrochloric acid solution is quantitatively input by the acid liquid quantitative meter D 28, and after the shock stays for 8 hours , open the acid liquid output valve 29, so that the supernatant liquid enters the MAP reaction tank 12 for mixed reaction, and the solid phase product residue in the solid phase oscillator 25 is regularly cleaned and discharged.

5) The liquid phase product enters the MAP reaction tank 12 through the liquid flow meter 9, monitors and adjusts the acid-base environment in the MAP reaction tank 12 through the pH online monitor 22 and the regulating pool 23 filled with lye, and maintains the pH in the MAP reaction tank 9.0 to 10.7; the magnesium chloride and potassium dihydrogen phosphate dry powder are transported into the MAP reaction tank 12 through the magnesium chloride quantitative feeder D19 and the potassium dihydrogen phosphate quantitative feeder D20 respectively, and are stirred and dissolved by the low-speed stirring motor M13 to participate in the MAP reaction.

Application example 1

The algae liquid salvaged from Taihu Lake and entering the algae water separation station has a water content of 96%, TN and TP concentrations of 3268mg/L and 180.63mg/L respectively, and enters the MAP after being treated by supercritical water gasification at 500°C for 5 minutes React in the reaction tank, and stay for 10 minutes after fully stirring. After the precipitate is dried in the drying room, the properties of the finished fertilizer obtained are shown in Table 1.

Application example 2

The algae liquid salvaged from Taihu Lake and entering the algae water separation station is dehydrated and concentrated through the dehydration device to increase the concentration of the dehydrated and concentrated algae liquid, and the water content is reduced to 86%. After 5 minutes of supercritical water gasification treatment, it enters the MAP reaction tank for reaction, fully stirs and stays for 20 minutes, and precipitates into the drying room for drying to obtain the properties of the finished fertilizer as shown in Table 1.

Table 1 Properties of the finished fertilizers obtained

After supercritical water treatment, the MAP method is used to recover the nitrogen and phosphorus in the salvaged algae liquid. On the one hand, in order to reduce the nitrogen and phosphorus nutrient levels in eutrophic lakes, it solves the problem of salvaging blue-green algae, and the extremely short reaction process The time and residence time can be more flexible to cope with the huge production of blue-green algae outbreaks. In 2011, a total of 970,000 tons of blue-green algae with a water content of about 98% were salvaged from Taihu Lake, which is equivalent to nearly 500 tons of nitrogen and 100 tons of phosphorus directly from the lake. The method of recovering nitrogen and phosphorus by MAP after supercritical water gasification treatment can quickly and efficiently realize the harmless treatment and resource utilization of salvaged cyanobacteria;

On the other hand, the present invention converts the nitrogen and phosphorus in salvaged blue-green algae into usable agricultural fertilizers, and the conversion efficiency is fast and efficient, and the conversion efficiency can reach 90%, which is much higher than the existing P element recovery method that only recovers liquid phase products , to alleviate the economic achievements, environmental pollution, and depleted phosphate rock resources in the production process of nitrogen and phosphorus fertilizers. If all the nitrogen and phosphorus in the cyanobacteria salvaged in Taihu Lake in 2011 are recovered by MAP, about 8,500 tons of MAP crystal fertilizers can be obtained; reduce While reducing the internal pollution load of rivers and lakes, certain economic benefits have been achieved, and the depletion of P ore resources and environmental pollution during fertilizer production have been alleviated.

Claims (4)

1. the device of nitrogen phosphorus is reclaimed with the supercritical water gasification product of blue-green algae algae solution, it is characterised in that including hold-up tank（1）, enter Mouth valve（2）, high-pressure plunger pump（3）, outlet valve（4）, heat exchanger（5）, gas-liquid flow valve（6）, gas-liquid separator tank（7）, it is wet Formula gas flowmeter（8）, fluid flowmeter（9）, counterbalance valve（10）, supercritical reaction device（11）, MAP retort（12）, low speed Stirring motor M（13）, magnesium chloride storagetank（14）, potassium dihydrogen phosphate storagetank（15）, system pressure regulating valve（16）, magnesium chloride Control valve（17）, potassium dihydrogen phosphate control valve（18）, magnesium chloride constant feeder D（19）, potassium dihydrogen phosphate constant feeder D （20）, do between drying（21）, pH on-line computing models（22）, regulate and control pond（23）, MAP crystal transfer valves（24）, solid phase oscillator（25）, Acid solution storagetank（26）, sour hydraulic control valve（27）, acid solution quantitative scoring D（28）, acid solution delivery valve（29）, control valve（30）；Wherein, Hold-up tank（1）The first efferent duct pass sequentially through inlet valve（2）, high-pressure plunger pump（3）, outlet valve（4）With heat exchanger（5）'s First input pipe is connected, heat exchanger（5）The first efferent duct pass through counterbalance valve（10）With supercritical reaction device（11）Input Pipe is connected, supercritical reaction device（11）The first efferent duct pass through system pressure regulating valve（16）With heat exchanger（5）Second Input pipe is connected, supercritical reaction device（11）The second efferent duct by controlling valve（30）With solid phase oscillator（25）It is first defeated Enter pipe to be connected, acid solution storagetank（26）Pass sequentially through sour hydraulic control valve（27）, acid solution quantitative scoring D（28）With solid phase oscillator（25） The second input pipe be connected, solid phase oscillator（25）The first efferent duct pass through acid solution delivery valve（29）With supercritical reaction device （11）Input pipe be connected, solid phase oscillator（25）The second efferent duct output solid product；

Heat exchanger（5）The second efferent duct pass through gas-liquid flow valve（6）With gas-liquid separator tank（7）Input pipe be connected, gas Liquid/gas separator tank（7）The first efferent duct pass through wet gas flow meter（8）Between dry baking（21）The first input pipe be connected, gas Liquid/gas separator tank（7）The second efferent duct pass through fluid flowmeter（9）With MAP retort（12）Input pipe be connected, magnesium chloride Storagetank（14）Pass sequentially through magnesium chloride control valve（17）, magnesium chloride constant feeder D（19）With MAP retort（12）Input Pipe is connected, potassium dihydrogen phosphate storagetank（15）Pass sequentially through potassium dihydrogen phosphate control valve（18）, potassium dihydrogen phosphate constant feeder D （20）With MAP retort（12）Input pipe be connected, MAP retort（12）The first efferent duct pass through MAP crystal transfer valves （24）Between dry baking（21）The second input pipe be connected, do dry between（21）The first efferent duct output gas-phase product, second output Pipe exports finished product fertilizer, MAP retort（12）The second efferent duct output supernatant, pH on-line computing models（22）With regulation and control pond （23）MAP retort is inserted by pipeline after being connected in parallel（12）It is interior, stirring at low speed motor M（13）Flabellum be placed in MAP reaction Tank（12）It is interior.

2. the device that the supercritical water gasification product with blue-green algae algae solution described in claim 1 reclaims nitrogen phosphorus reclaims bloom blue algae algae The method of nitrogen phosphorus in liquid, it is characterised in that comprise the following steps：

1）The blue-green algae algae solution of moisture content 98% ~ 99% for salvaging disembarkation is entered into hold-up tank（1）, it is pending after the separation of algae water；

2）The inlet valve of high-pressure plunger pump is opened during on-test（2）, high-pressure plunger pump is opened, and open heat exchanger（5）'s Heater, 300 DEG C are risen to by its temperature, open supercritical reaction device（11）It is warming up to 450 ~ 500 DEG C；

3）Open algae solution outlet valve（4）, the algae solution after the separation of algae water is entered heat exchanger（5）, it is warming up to by heat exchanger 250℃；Then counterbalance valve is passed through（10）Into supercritical reaction device（11）, 400 ~ 500 DEG C, pressure are reached in reactor temperature 22 ~ 25Mpa, reaches supercriticality, stops 3 ~ 5 minutes laggard water-filling gasification reactions；After reaction terminates, open system pressure and adjust Save valve（16）, gas-liquid mixed phase product is entered heat exchanger（5）, by heat exchanger by the pending algae solution liter of next stage Temperature to 250 DEG C, and during cause gas-liquid mixed phase product temperatur reduction, open gas-liquid flow valve（6）Into gas-liquid separator Tank（7）, the liquid product of fuel gas and rich Nitrogen-and Phosphorus-containing is obtained after gas-liquid separation, and pass through wet gas flow meter（8）, utilize Gas-phase product that band has surplus heat and it is dry dry between（21）Finished product is made in the fertilizer drying subsequently obtained；

4）After supercritical reaction terminates, inorganic solid phase product is by supercritical reaction device（11）Bottom is discharged into solid phase oscillator （25）, open sour hydraulic control valve（27）, pass through acid solution quantitative scoring D（28）Hydrochloric acid solution is quantitatively inputted, concussion is stopped after 8h, is opened Acid solution delivery valve（29）, supernatant is entered MAP retort（12）Hybrid reaction, solid phase oscillator（25）In solid product it is residual Slag periodic cleaning is discharged；

5）Liquid product is through fluid flowmeter（9）Into MAP retort（12）, pass through pH on-line computing models（22）With fill alkali lye Regulation and control pond（23）Monitoring regulation MAP retort（12）In acid or alkali environment, maintain MAP retort in pH be 9.0 ~ 10.7； Magnesium chloride and potassium dihydrogen phosphate dry powder are passed through into magnesium chloride constant feeder D respectively（19）With potassium dihydrogen phosphate constant feeder D （20）Deliver into MAP retort（12）In, and by stirring at low speed motor M（13）MAP reactions are participated in after stirring and dissolving.

3. the supercritical water gasification product according to claim 2 with blue-green algae algae solution reclaims the device recycle-water Chinese blue of nitrogen phosphorus The method of nitrogen phosphorus in algae algae solution, it is characterised in that the acid solution storagetank（26）The acid solution of middle storage is hydrochloric acid.

4. the supercritical water gasification product with blue-green algae algae solution according to Claims 2 or 3 reclaims the device recycle-water of nitrogen phosphorus The method of nitrogen phosphorus in Chinese blue algae algae solution, it is characterised in that the solid phase oscillator（25）Using sequencing batch operation mode.