1. A process method for preparing derived fuel by modifying mixed sludge and cooperating with high-pressure dehydration is characterized by comprising the following steps:

1) modifying by quenching and tempering

The sludge-based biochar doped with the ferric sulfate flocculant is used as a conditioning agent for conditioning and modifying, and is prepared by removing impurities and pyrolyzing activated sludge; the addition of the sludge-based biochar can improve the dehydration performance of the sludge, increase the organic matter content of the sludge to a certain extent, and the conditioning is also beneficial to the separation of inorganic and organic components in the later period;

2) diluting to remove impurities

The metal impurity removal process comprises the following steps: the wet magnetic separator is provided with a wet magnetic separator, a sludge storage box and a metal sundry collecting box, wherein an upper crawler and a lower crawler are arranged inside the wet magnetic separator, the upper crawler and the lower crawler are horizontally placed and are partially overlapped, and the overlapped part of the upper crawler has magnetism. When the lower crawler belt conveys the mixed sludge diluted by adding water through the overlapping part of the upper crawler belt, metal impurities in the mixed sludge can be magnetically adsorbed to the upper crawler belt and fall into the metal impurity collecting box below when passing through the nonmagnetic section at the rear end of the upper crawler belt. The mixed sludge after metal removal is sent to a sludge storage tank through a lower crawler belt, and inorganic impurity removal treatment is continued in the later period;

the inorganic impurity removal treatment process comprises the following steps: the sludge filter box is provided with a sludge filter box, filter screens, a sludge storage box and a sundry collecting box, metal filter screens with different filter diameters are sequentially placed in the sludge filter box at equal intervals, the metal filter screens and the box wall are inclined at a certain angle, and the diameters of filter holes of the metal filter screens are gradually reduced from top to bottom; the mixed sludge subjected to metal impurity removal enters a filter box, sequentially passes through an upper layer, a middle layer and a lower layer of filter screens with different apertures, then falls into a sludge storage box right below the filter screens, and inorganic impurities filtered by the filter screens fall into an adjacent impurity collecting box, so that subsequent treatment is facilitated;

3) separation of organic and inorganic components

The separation of organic and inorganic components of the mixed sludge is realized by adopting a cavitation and rotational flow mode, when the mixed sludge after the modification, dilution and impurity removal flows through the minimum cross section in the Venturi cavitation machine, the flow rate of the mixed sludge is increased, the pressure is reduced, when the pressure is reduced to steam pressure or even negative pressure, a large amount of cavitation bubbles are generated in the mixed sludge, and along with the rapid recovery of the pressure, the cavitation bubbles are instantly destroyed to generate a cavitation phenomenon so as to destroy cell walls of fine components in the mixed sludge and release components and cytoplasm contained in cells, and at the moment, the combined water in the mixed sludge is converted into a free water form, so that the later-stage separation and high-pressure dehydration of the organic and inorganic components are facilitated; the organic matter and the inorganic mineral component in the sludge are separated by a cyclone separator according to different specific gravities of the organic matter and the inorganic mineral component, the content of the organic component is further improved, the separated inorganic mineral is collected in an inorganic matter collecting tank below the cyclone separator, and the organic matter is conveyed to a plate-and-frame filter press through a pipeline above the cyclone separator for further high-pressure filter pressing and dehydration;

4) high pressure dewatering

And (3) carrying out high-pressure filter pressing on the mixed sludge by adopting a plate-and-frame filter press, wherein the filter-pressed sludge cake has lower water content and can be used as a derived fuel.

2. The process method for preparing the derivative fuel by the mixed sludge conditioning and modifying in cooperation with the high-pressure dewatering as claimed in claim 1, wherein in the step 1), the sludge conditioning and modifying process method is realized by configuring a chemical box and a sludge conditioning tank.

3. The process method for preparing the derivative fuel by modifying and cooperating the mixed sludge with quenching and tempering and high-pressure dehydration according to claim 1 or 2, wherein in the step 3), the process method for separating the organic and inorganic components is realized by configuring a Venturi cavitation machine 13 and a cyclone separator 14.

4. The device for preparing the derivative fuel by the conditioning and modification of the mixed sludge and the high-pressure dehydration in cooperation with the process method for preparing the derivative fuel according to claim 1 is characterized by comprising a sludge storage bin, a chemical box, a sludge conditioning tank, a sludge diluting tank, a wet magnetic separator, a sludge filter box, a Venturi cavitation machine, a cyclone separator and a sludge plate-and-frame filter press, wherein regulating valves are arranged between the sludge storage bin and the sludge conditioning tank and between the chemical box and the sludge conditioning tank, and a stirring device 1 and a blocking device are arranged in the sludge conditioning tank; a delivery pump is arranged between the sludge conditioning tank and the sludge diluting tank; one side of the sludge diluting tank is connected with a water outlet, the other side of the sludge diluting tank is connected with a water inlet, and the sludge diluting tank is provided with a stirring device; the discharge port of the sludge dilution tank is connected with the inlet of the wet magnetic separator, the lower end of the wet magnetic separator is respectively provided with a sludge storage tank and a metal sundries collecting box, and a conveying pump is connected between the sludge storage tank and the sludge filter box; a sludge storage tank and a sundries collecting box are arranged at the lower end of the sludge filtering box side by side; a delivery pump and a three-way valve are connected between the sludge storage tank and the Venturi cavitation machine; the discharge port of the Venturi cavitation machine is connected with the inlet of the cyclone separator, the lower end of the cyclone separator is connected with an inorganic matter collecting tank, and the upper end of the cyclone separator is connected to the sludge plate-and-frame filter press.

5. The device of claim 4, wherein the sludge plate-and-frame filter press comprises a filter plate and a filter frame, a cross beam, a water outlet and a discharging device, the sludge plate-and-frame filter press comprises the filter plate and the filter frame, the cross beam, the water outlet and the discharging device, the filter plate and the filter frame are positioned on the cross beam, the side-by-side water outlet is connected below the filter plate and the filter frame, and the mud cake discharging device is arranged below the water outlet.

Background

With the development of society and the continuous expansion of urbanization scale, the sludge yield is increased year by year, and the sludge treatment problem is urgently needed to be solved. At present, the reduction and stabilization treatment of sludge have been successful, but the resource utilization technology of sludge still needs to be developed, wherein more and more attention is paid to the preparation of derivative fuel by using sludge as a way for resource treatment of sludge. Because the sludge has the characteristics of high water content, rich organic matters, unfavorable transportation, unstable properties and the like, the sludge needs to be modified by tempering in the early stage of sludge treatment to reduce the initial water content and separate organic and inorganic components.

The existing sludge conditioning technology can be divided into three categories according to the quality of a conditioning machine: chemical, physical and biological methods, among which the chemical method is widely used because of its advantages of reliable effect, simple equipment, convenient operation, investment and running cost saving, etc. The conditioner used by the chemical method can be divided into an inorganic flocculant and an organic flocculant, wherein the inorganic flocculant comprises a common aluminum salt flocculant, a common iron salt flocculant and the like, but the chemical conditioner consumes a large amount of chemical agents in the production and modification processes, and although the use of the conditioner obviously reduces the water content of sludge, the conditioner pollutes the ecological environment. With the continuous development of sludge conditioning technology, inorganic polymeric flocculant and organic flocculant with better flocculation effect than the traditional flocculant are generated in succession. In addition, the sludge dewatering effect is reduced rapidly due to the fact that the flocculating agent is used singly and the flocculating agent is added excessively, the situation can be avoided by reasonably combining the flocculating agent, and the effect is better.

Therefore, in consideration of the defects of the traditional chemical conditioner in preparation and conditioning and the conditioning effect obtained by combining medicaments, the application discloses the sludge-based biochar doped with the cationic flocculant, wherein the cationic flocculant is a ferric sulfate flocculant. The sludge-based biochar prepared from activated sludge by a certain method is proved to be beneficial to sludge conditioning modification, and can reduce the initial water content of the sludge with larger water content to below 50%. The sludge-based biochar doped with the ferric sulfate flocculant as the sludge conditioner has the following advantages: 1. the sludge conditioning effect is good, and the water content can be reduced to below 50%; 2. the doped ferric sulfate flocculating agent can improve the conditioning effect of the conditioner, does not contain harmful substances such as aluminum, chlorine, heavy metal ions and the like, and has small damage to the ecological environment; 3. the applicable initial pH value range of the sludge is wide, and the sludge has small corrosivity on treatment equipment; 4. the organic matter content of the sludge is not changed, the organic performance of the sludge can be improved to a certain extent, and the inorganic and organic components can be separated after the sludge is tempered.

Disclosure of Invention

In order to overcome the defects of the prior art, the invention provides a process method and a device for preparing derivative fuel by modifying and cooperating with high-pressure dehydration of mixed sludge, which are used for carrying out pretreatment such as modification and impurity removal on the sludge, simultaneously cooperating with cavitation cyclone to preliminarily separate organic and inorganic components in the sludge, and carrying out high-pressure dehydration on the separated organic components to prepare the derivative fuel, thereby laying a foundation for the subsequent high-efficiency resource utilization of the sludge.

The technical scheme adopted by the invention for solving the technical problems is as follows:

a process method for preparing derived fuel by modifying mixed sludge and cooperating with high-pressure dehydration comprises the following steps:

1) modifying by quenching and tempering

The sludge-based biochar doped with the ferric sulfate flocculant is used as a conditioning agent for conditioning and modifying, and is prepared by removing impurities and pyrolyzing activated sludge; the addition of the sludge-based biochar can improve the dehydration performance of the sludge, increase the organic matter content of the sludge to a certain extent, and the conditioning is also beneficial to the separation of inorganic and organic components in the later period;

2) diluting to remove impurities

The metal impurity removal process comprises the following steps: the wet magnetic separator is provided with a wet magnetic separator, a sludge storage box and a metal sundry collecting box, wherein an upper crawler and a lower crawler are arranged inside the wet magnetic separator, the upper crawler and the lower crawler are horizontally placed and are partially overlapped, and the overlapped part of the upper crawler has magnetism. When the lower crawler belt conveys the mixed sludge diluted by adding water through the overlapping part of the upper crawler belt, metal impurities in the mixed sludge can be magnetically adsorbed to the upper crawler belt and fall into the metal impurity collecting box below when passing through the nonmagnetic section at the rear end of the upper crawler belt. The mixed sludge after metal removal is sent to a sludge storage tank through a lower crawler belt, and inorganic impurity removal treatment is continued in the later period;

the inorganic impurity removal treatment process comprises the following steps: the sludge filter box is provided with a sludge filter box, filter screens, a sludge storage box and a sundry collecting box, metal filter screens with different filter diameters are sequentially placed in the sludge filter box at equal intervals, the metal filter screens and the box wall are inclined at a certain angle, and the diameters of filter holes of the metal filter screens are gradually reduced from top to bottom; the mixed sludge subjected to metal impurity removal enters a filter box, sequentially passes through an upper layer, a middle layer and a lower layer of filter screens with different apertures, then falls into a sludge storage box right below the filter screens, and inorganic impurities filtered by the filter screens fall into an adjacent impurity collecting box, so that subsequent treatment is facilitated;

3) separation of organic and inorganic components

The separation of organic and inorganic components of the mixed sludge is realized by adopting a cavitation and rotational flow mode, when the mixed sludge after the modification, dilution and impurity removal flows through the minimum cross section in the Venturi cavitation machine, the flow rate of the mixed sludge is increased, the pressure is reduced, when the pressure is reduced to steam pressure or even negative pressure, a large amount of cavitation bubbles are generated in the mixed sludge, and along with the rapid recovery of the pressure, the cavitation bubbles are instantly destroyed to generate a cavitation phenomenon so as to destroy cell walls of fine components in the mixed sludge and release components and cytoplasm contained in cells, and at the moment, the combined water in the mixed sludge is converted into a free water form, so that the later-stage separation and high-pressure dehydration of the organic and inorganic components are facilitated; the organic matter and the inorganic mineral component in the sludge are separated by a cyclone separator according to different specific gravities of the organic matter and the inorganic mineral component, the content of the organic component is further improved, the separated inorganic mineral is collected in an inorganic matter collecting tank below the cyclone separator, and the organic matter is conveyed to a plate-and-frame filter press through a pipeline above the cyclone separator for further high-pressure filter pressing and dehydration;

4) high pressure dewatering

And (3) carrying out high-pressure filter pressing on the mixed sludge by adopting a plate-and-frame filter press, wherein the filter-pressed sludge cake has lower water content and can be used as a derived fuel.

Further, in the step 1), the sludge conditioning and modifying process method is realized by configuring a chemical box and a sludge conditioning tank.

Still further, in the step 3), the organic and inorganic component separation process is realized by configuring a venturi cavitation machine 13 and a cyclone separator 14.

A device for preparing derivative fuel by modifying mixed sludge through conditioning and high-pressure dehydration, which comprises a sludge storage bin, a chemical box, a sludge conditioning tank, a sludge diluting tank, a wet magnetic separator, a sludge filtering box, a Venturi cavitation machine, a cyclone separator and a sludge plate-and-frame filter press, wherein regulating valves are arranged between the sludge storage bin and the sludge conditioning tank and between the chemical box and the sludge conditioning tank, and a stirring device 1 and a separation device are arranged in the sludge conditioning tank; a delivery pump is arranged between the sludge conditioning tank and the sludge diluting tank; one side of the sludge diluting tank is connected with a water outlet, the other side of the sludge diluting tank is connected with a water inlet, and the sludge diluting tank is provided with a stirring device; the discharge port of the sludge dilution tank is connected with the inlet of the wet magnetic separator, the lower end of the wet magnetic separator is respectively provided with a sludge storage tank and a metal sundries collecting box, and a conveying pump is connected between the sludge storage tank and the sludge filter box; a sludge storage tank and a sundries collecting box are arranged at the lower end of the sludge filtering box side by side; a delivery pump and a three-way valve are connected between the sludge storage tank and the Venturi cavitation machine; the discharge port of the Venturi cavitation machine is connected with the inlet of the cyclone separator, the lower end of the cyclone separator is connected with an inorganic matter collecting tank, and the upper end of the cyclone separator is connected to the sludge plate-and-frame filter press.

The sludge plate-and-frame filter press comprises a filter plate, a filter frame, a cross beam, a water outlet and a discharging device, wherein the filter plate and the filter frame are positioned on the cross beam, the water outlets are connected below the filter plate and the filter frame side by side, and the sludge cake discharging device is arranged below the water outlet.

The invention has the following beneficial effects: (1) the application range is wide, and the sludge treatment agent can be suitable for municipal sludge, industrial sludge or river sludge; (2) the dehydration effect is obvious, the sludge-based biochar mixed with the ferric sulfate flocculant is used as a conditioner, the dehydration effect is good, the environmental pollution is small, and the content of organic components in the sludge can be increased; the cavitation rotational flow can convert the bound water in the sludge into free water, which is more beneficial to the subsequent filter pressing dehydration; (3) the impurities are thoroughly removed, magnetic metal impurities, large inorganic impurities and inorganic minerals contained in the mixed sludge can be removed, and the sludge dewatering efficiency and the organic matter content of sludge cakes can be improved; (4) the mud cake has high organic matter content and has application potential as a derivative material.

Drawings

FIG. 1 is a schematic diagram of a device for preparing derived fuel by modifying mixed sludge through tempering and cooperating with high-pressure dehydration. 1. The sludge storage bin 2, the regulating valve 13, the regulating valve 24, the chemical box 5, the sludge conditioning tank 5-1, the stirring device 5-2, the blocking device 6, the delivery pump 7, the sludge dilution tank 7-1, the stirring device 7-2, the water inlet 7-3, the water outlet 8, the wet magnetic separator 9, the sludge storage tank 10, the metal impurity collecting box 11, the sludge filtering box 11-1, the filter screen 11-2, the sludge storage tank 11-3, the impurity collecting box 12, the three-way valve 13, the venturi cavitation machine 14, the cyclone separator 14-1, the screening filter screen 14-2, the inorganic mineral collecting tank 15, the filter press plate frame 15-1, the filter plate and the filter frame 15-2, the beam 15-3, the water outlet 15-4 and the discharging device.

Detailed Description

The invention is further described below with reference to the accompanying drawings.

Referring to fig. 1, a process method for preparing derived fuel by modifying mixed sludge and cooperating with high-pressure dehydration comprises the following steps:

1) modifying by quenching and tempering

The sludge conditioning and modifying process method is realized by configuring the chemical agent box 4 and the sludge conditioning tank 5, and because a large amount of chemical agents such as sodium hydroxide, an initiator and the like are consumed in the production and modification processes of the traditional conditioner or flocculant, the water content of the sludge is obviously reduced by using the conditioner, but the environment is seriously damaged. Therefore, the invention provides a conditioner which uses the sludge-based biochar doped with the ferric sulfate flocculant for conditioning and modifying in consideration of the defects of the traditional conditioner, and the sludge-based biochar is prepared by removing impurities and pyrolyzing activated sludge. The addition of the sludge-based biochar can improve the dehydration performance of the sludge, increase the organic matter content of the sludge to a certain extent, and the conditioning is also beneficial to the separation of inorganic and organic components in the later stage, and the blending of the ferric salt flocculant can improve the dehydration performance of the sludge-based biochar, and the ferric salt is also beneficial to the stabilization of heavy metals in the sludge.

2) Diluting to remove impurities

The dilution and impurity removal process method is mainly completed by a sludge dilution tank 7, a wet magnetic separator 8 and a sludge filter box 11. The mixed sludge contains a large amount of inorganic impurities, such as cloth ends, bricks and the like, and other metal impurities, and the existence of the inorganic impurities affects the quality of subsequent mud cake output and the overall treatment efficiency, so that the impurity removal in the sludge treatment is necessary. The impurity removal process is realized by the metal impurity removal and the inorganic bulk impurity removal together;

the process method for solving the problem of metal impurity removal comprises the following steps: a wet magnetic separator 8, a sludge storage tank 9 and a metal sundries collecting box 10 are arranged. The wet magnetic separator is internally provided with an upper crawler belt and a lower crawler belt, the upper crawler belt and the lower crawler belt are horizontally arranged and partially overlapped, and the overlapped part of the upper crawler belt has magnetism. When the lower crawler belt conveys the mixed sludge diluted by adding water through the overlapping part of the upper crawler belt, metal impurities in the mixed sludge can be magnetically adsorbed to the upper crawler belt and fall into the metal impurity collecting box below when passing through the nonmagnetic section at the rear end of the upper crawler belt. And (4) conveying the mixed sludge subjected to metal removal to a sludge storage tank through a lower crawler, and continuing the inorganic impurity removal treatment in the later period.

The process method for solving the problem of inorganic impurities such as massive inorganic substances, cloth ends and the like comprises the following steps: the sludge filter tank 11, the filter screen 11-1, the sludge storage tank 11-2 and the sundries collecting tank 11-3 are arranged. The inside equidistant metal filter screen of placing different diameters in proper order of rose box, metal filter screen and tank wall are certain angle slope, and the filtration pore diameter of extremely up and down metal filter screen reduces step by step. The mixed sludge subjected to metal impurity removal enters a filter box, sequentially passes through an upper layer, a middle layer and a lower layer of filter screens with different apertures, then falls into a sludge storage box right below the filter screens, and inorganic impurities filtered by the filter screens fall into an adjacent impurity collecting box, so that the subsequent treatment is facilitated. The rose box can effectively filter a large amount of inorganic impurity that contains in the mixed mud, like fragment of brick, cloth etc. the setting of the different aperture filter screens of three-layer can get rid of not unidimensional inorganic impurity effectively, and the layering can alleviate to a certain extent because the filter screen filters the jam problem that causes simultaneously, but the filter screen of this rose box need regularly wash and change.

3) Separation of organic and inorganic components

The organic and inorganic component separation process method covers the arrangement and operation of the Venturi cavitation machine 13 and the cyclone separator 14. The separation of organic and inorganic components of the mixed sludge is realized by adopting a cavitation and rotational flow mode, when the mixed sludge after the modification, dilution and impurity removal flows through the minimum cross section in the Venturi cavitation machine, the flow rate of the mixed sludge is increased, the pressure is reduced, when the pressure is reduced to steam pressure or even negative pressure, a large amount of cavitation bubbles are generated in the mixed sludge, and along with the rapid recovery of the pressure, the cavitation bubbles are instantly destroyed to generate a cavitation phenomenon so as to destroy cell walls of fine components in the mixed sludge and release components and cytoplasm in cells, and at the moment, the combined water in the mixed sludge is converted into a free water form, so that the later-stage separation and high-pressure dehydration of the organic and inorganic components are facilitated. The organic matter and the inorganic mineral component in the sludge are separated by the cyclone separator due to different specific gravities, the content of the organic component is further improved, the separated inorganic mineral is collected in the inorganic matter collecting tank below the cyclone separator, and the organic matter is conveyed to the plate-and-frame filter press through the pipeline above the cyclone separator for further high-pressure filter pressing and dehydration.

4) High pressure dewatering

The mixed sludge after quenching and tempering modification, dilution, metal impurity removal, inorganic bulk impurity removal, cavitation and component separation has better dewatering capacity. Based on the method, the plate-and-frame filter press is adopted to carry out high-pressure filter pressing on the mixed sludge, and the mud cake after filter pressing has lower water content and can be used as a derived fuel.

A device for preparing derivative fuel by modifying mixed sludge through conditioning and high-pressure dehydration, which comprises a sludge storage bin 1, a chemical box 4, a sludge conditioning tank 5, a sludge diluting tank 7, a wet magnetic separator 8, a sludge filtering tank 11, a Venturi cavitation machine 13, a cyclone separator 14 and a sludge plate-and-frame filter press 15, wherein regulating valves 2 are arranged between the sludge storage bin 1 and the sludge conditioning tank 5 and between the chemical box 3 and the sludge conditioning tank 5; a stirring device 5-1 and a separation device 5-2 are arranged in the sludge conditioning tank 5; a delivery pump 6 is arranged between the sludge conditioning tank 5 and the sludge diluting tank 7; the left side of the sludge dilution tank 7 is connected with a water outlet 7-2, the right side of the sludge dilution tank 7 is connected with a water inlet 7-3, and the sludge dilution tank 7 is also provided with a stirring device 7-1; a discharge hole of the sludge dilution tank 7 is connected with an inlet of a wet magnetic separator 8, a sludge storage tank 9 and a metal sundries collecting box 10 are respectively placed at the lower end of the wet magnetic separator 8, and a conveying pump is connected between the sludge storage tank 9 and a sludge filter box 11; the lower end of the sludge filter tank 11 is provided with a sludge storage tank 11-2 and a sundries collecting box 11-3 in parallel; a delivery pump and a three-way valve 12 are connected between the sludge storage tank 11 and the Venturi cavitation machine 13; the discharge hole of the Venturi cavitation machine is connected with the inlet of a cyclone separator 14, the lower end of the cyclone separator 14 is connected with an inorganic matter collecting tank 14-2, and the upper end of the cyclone separator is connected with a sludge plate-and-frame filter press 15.

The sludge plate-and-frame filter press 15 comprises a filter plate and a filter frame 15-1, a cross beam 15-2, a water outlet 15-3 and a discharging device 15-4, wherein the filter plate and the filter frame 15-1 are positioned on the cross beam 15-2, the water outlets 15-3 are arranged below the filter plate and the filter frame 15-1 in parallel, and the mud cake discharging device 15-4 is arranged below the water outlet 15-3.

The working process of the embodiment is as follows: firstly, mixed sludge (with the water content of about 95%) in a sludge storage bin 1 is conveyed to a sludge conditioning tank 5 for conditioning and modification, and the flow of the sludge in a pipeline can be regulated and controlled by a regulating valve 2; the sludge conditioner (sludge-based biochar doped with a ferric sulfate flocculating agent) from the chemical box 4 is added into the mixed sludge stored in the sludge conditioning tank 5, and the sludge is conditioned and modified under the stirring action, so that the sludge dewatering capacity is improved; the sludge conditioning tank 5 is also provided with a stirring device 5-1 and a blocking valve 5-2 to ensure the conditioning time and the conditioning efficiency. The sludge after the modification is pumped into a sludge diluting tank 7 through a delivery pump 6 for water adding, stirring and diluting, and the water adding and draining process in the sludge diluting tank can be realized through a water inlet 7-2 and a water outlet 7-3. Secondly, the sludge after a series of pretreatment (tempering, modification and dilution) is sent to a wet magnetic separator 8 for metal impurity removal, when the sludge diluted by adding water is conveyed to the part overlapped with the upper and lower crawler belts by the lower crawler belt, the magnetic metal impurities in the sludge are adsorbed to the upper crawler belt, the magnetically adsorbed metal impurities fall into a metal impurity collecting box 10 for subsequent recycling, and the sludge subjected to metal impurity removal is temporarily stored in a sludge storage box 9. Then, pumping the sludge into a sludge filtering box 11 through a delivery pump for inorganic bulk impurity removal, wherein the sludge in the sludge filtering box 11 sequentially passes through three layers of metal filter screens 11-1 with different apertures and falls into a sludge storage box 11-2 right below, and the screened inorganic impurities fall into an impurity storage box 11-3 for subsequent treatment. The sludge after the conditioning modification, dilution and impurity removal enters a Venturi cavitation machine 13 to be subjected to hydrodynamic cavitation, cell walls of cells in the mixed sludge are damaged, bound water in the mixed sludge is further released, the sludge after the cavitation is sent into a cyclone separator 14 to be subjected to organic and inorganic component separation, inorganic minerals fall into an inorganic mineral collecting tank 14-2 below through a screening filter screen 14-1 under the action of the cyclone separator according to the difference of specific gravity of organic matters and inorganic minerals in the sludge, and the separated organic components enter a sludge plate-and-frame filter press 15 from the upper part of the cyclone separator to be subjected to high-pressure filter pressing dehydration to prepare derivative fuels.

The embodiments described in this specification are merely illustrative of implementations of the inventive concepts, which are intended for purposes of illustration only. The scope of the present invention should not be construed as being limited to the particular forms set forth in the examples, but rather as being defined by the claims and the equivalents thereof which can occur to those skilled in the art upon consideration of the present inventive concept.