CN113526815B

CN113526815B - Preparation method of sludge derived clean fuel

Info

Publication number: CN113526815B
Application number: CN202010304579.6A
Authority: CN
Inventors: 毛炳荣; 毛中元
Original assignee: Shanghai Woneng Environmental Protection Technology Co ltd
Current assignee: Shanghai Woneng Environmental Protection Technology Co ltd
Priority date: 2020-04-17
Filing date: 2020-04-17
Publication date: 2023-04-25
Anticipated expiration: 2040-04-17
Also published as: CN113526815A

Abstract

The invention discloses a preparation method of a sludge derived clean fuel, which comprises the following steps: s1, pretreating sewage containing sludge to obtain sewage A; s2, adding a sewage modification conditioner into the sewage A treated in the step S1, uniformly mixing and aging to obtain sewage B; s3, introducing ozone micro-nano bubbles into the sewage B treated in the step S2, and simultaneously carrying out ultrasonic treatment on the sewage B introduced with the ozone micro-nano bubbles to obtain sewage C; s4, mechanically dehydrating the sewage C treated in the step S3 after being treated by a high-voltage electronic pulse technology to obtain sludge; and S5, adding auxiliary fuel into the sludge treated in the step S4, fully stirring and uniformly mixing to obtain a mixture, naturally drying, and pressing to form the sludge derivative clean fuel. The invention has simple process and no secondary pollution, is convenient for realizing industrialized popularization and application, and greatly improves the combustion performance of main organic matters in the sludge.

Description

Preparation method of sludge derived clean fuel

Technical Field

The invention relates to the technical field of sludge treatment, in particular to a preparation method of a sludge derived clean fuel.

Background

Sludge is the residual solid waste generated after sewage treatment, has high moisture content and is rich in sulfur oxides, heavy metal ions, pathogens and other toxic and harmful substances, and the sludge is extremely harmful to the environment. With the development of social productivity, the annual output of sludge in China is increased year by year, and the stabilization, reduction and harmless treatment of the sludge are now hot environmental problems. However, the high water content of the sludge is an important factor for limiting the resource utilization of the sludge, and the traditional mechanical dehydration mode can only reduce the water content of the sludge to 75-85%, so that the effect is very limited and the treatment efficiency is low. The method is mainly characterized in that microorganisms in the sludge secrete Extracellular Polymers (EPS) to enable the sludge to be in an organic floccule structure, so that the sludge has extremely strong hydrophilicity and wrapping effect; in addition, the sludge has high organic matter and colloid content, so that the solid structure of the sludge has high compressibility, and the water filtering channel is blocked in the mechanical dehydration and compression process of the sludge, so that the filterability of the sludge is reduced, and the solid-liquid separation in the sludge is inhibited. From the eighties of the twentieth century, china began to introduce a garbage incineration power plant and a sludge mixed coal incineration power plant which use an incineration technology to treat household garbage and generate power by utilizing waste heat. The sludge mixed coal burns to generate electricity, so that the efficiency of the coal-fired power plant is reduced, the corrosion of a boiler is aggravated, and the emission risk of dioxin pollutants exists. Therefore, research on a comprehensive utilization method of sludge harmless, energy and large-scale is needed, so that not only can the serious pollution problem be solved, but also clean fuel which can be directly utilized and accords with the fuel discharge standard can be obtained.

Disclosure of Invention

The invention aims to overcome the defects, and provides a preparation method of the sludge-derived clean fuel, which is developed by greatly reducing the water content of sludge, rapidly and permanently deodorizing, solidifying heavy metals and improving the heat value in the sewage treatment process of a sewage treatment plant, has simple process and no secondary pollution, is convenient for realizing industrialized popularization and application, greatly improves the combustion performance of main organic matters in sewage by oxidizing and nitrifying organic matters with high internal water bacterial groups through a sewage modification conditioner, simultaneously breaks wall of sludge-containing microorganisms in the sewage, rapidly heats and evaporates water in cell membranes in the oxidizing and nitrifying process, reduces the cost of subsequent sludge drying and improves the drying effect of the subsequent sludge; the extracellular polymer and the cell wall in the sewage are destroyed by the strong oxidizing property of the ozone, the ozone is introduced into the sewage in the form of ozone micro-nano bubbles, the specific surface area of the ozone bubbles is greatly increased, the gas-water contact area is increased, and meanwhile, the residence time of the micro bubbles in the water is prolonged, so that the mass transfer efficiency of a gas-liquid interface is enhanced; the cavitation core in the liquid phase is increased by the ozone micro-nano bubbles, and the ozone micro-nano bubbles and ultrasonic wave cooperate to improve the separation efficiency and effect of the oil phase in the sewage; the sewage is treated by a high-voltage electronic pulse technology, so that a mechanical dehydration effect is greatly provided, the water content of dehydrated sludge is lower than 30%, and finally, the heat value of the sludge derived clean fuel can be further improved by adding auxiliary fuel into the sludge.

In order to achieve the above purpose, the invention provides the following technical scheme, namely a preparation method of a sludge derived clean fuel, which comprises the following steps:

s1, pretreating the water containing the sludge, and removing peculiar smell of the sewage and heavy metal ions contained in the sewage to obtain sewage A;

s2, adding a sewage modification conditioner into the sewage A treated in the step S1, uniformly mixing, and aging for 1-2.5 hours to obtain sewage B; the sewage modified conditioner comprises a component A and a component B, wherein the mass ratio of the sewage A to the component B is 100:0.2 to 1.5:0.1 to 0.25; wherein the component A consists of the following raw materials in parts by weight: 5-20 parts of hypochlorite, 8-20 parts of dichromate, 8-20 parts of chromate, 20-35 parts of copper nitrate, 20-38 parts of calcium nitrate and 25-41 parts of sodium nitrate, wherein the component B comprises the following raw materials in parts by weight: 3 to 6 parts of bacillus subtilis, 1 to 4 parts of lactobacillus and 1.5 to 5 parts of aspergillus niger;

s3, introducing ozone micro-nano bubbles into the sewage B obtained after the treatment in the step S2, performing aeration through the ozone micro-nano bubbles to enable ozone to fully contact the sewage B, performing ultrasonic treatment on the sewage B introduced with the ozone micro-nano bubbles, destroying extracellular polymers and cell walls in the sewage through strong oxidizing property of the ozone micro-nano bubbles, and separating an oil phase contained in the sewage B through synergistic effect of the ozone micro-nano bubbles and ultrasonic waves to obtain sewage C;

s4, treating the sewage C treated in the step S3 by adopting a high-voltage electronic pulse technology, and then mechanically dehydrating until the water content is lower than 30% to obtain sludge;

s5, adding auxiliary fuel into the sludge treated in the step S4, fully stirring and uniformly mixing to obtain a mixture, naturally drying the mixture until the water content is lower than 20%, and sending the mixture into a pressing machine for pressing and forming to obtain the sludge derived clean fuel; wherein the mass ratio of the sludge obtained after the treatment in the step S4 to the auxiliary fuel is 25-80: 10 to 45.

By adopting the technical scheme, the sewage after peculiar smell and heavy metal ions are removed is modified and filled by the sewage modification conditioner, wherein the component A is used for oxidizing and nitrifying organic matters with argillaceous and high internal water bacterial groups in the sewage, so that the combustion performance of main organic matters in the sludge can be greatly improved, pathogen microorganisms in the sludge can be killed, and the component B is used for breaking the wall of the microorganisms in the sewage, so that the moisture in a cell membrane is quickly heated and evaporated in the oxidizing and nitrifying process, the cost of subsequent sludge drying is reduced, and the drying effect of the subsequent sludge is improved; the extracellular polymer and the cell wall in the sewage are destroyed by the strong oxidizing property of the ozone, the ozone is introduced into the sewage in the form of ozone micro-nano bubbles, the specific surface area of the ozone bubbles is greatly increased, the gas-water contact area is increased, and meanwhile, the residence time of the micro bubbles in the water is prolonged, so that the mass transfer efficiency of a gas-liquid interface is enhanced; the cavitation core in the liquid phase is increased by the ozone micro-nano bubbles, and the ozone micro-nano bubbles and ultrasonic wave cooperate to improve the separation efficiency and effect of the oil phase in the sewage; the instant high-voltage pulse electric field generated instantaneously between the two electrodes acts on the sludge C to dissolve out intracellular substances, so that the aim of destroying microorganism cells is fulfilled, the effective mechanical dehydration can be realized, and the water content of the sludge is greatly reduced; the heat value of the sludge-derived clean fuel can be further improved by adding an auxiliary fuel to the sludge with low water content.

The preparation method of the sludge derived clean fuel, wherein the step S1 comprises the following steps:

s11, adding ferric salt after adjusting the pH value of the sewage to 4-5 to obtain Fe in the sewage ³⁺ The concentration of the wastewater is 0.2 to 0.6g/L, the wastewater is stirred for 20 to 30 minutes and then is placed in an electrolytic cell, the power supply of the electrolytic cell is connected for electrolysis, and the wastewater for removing heavy metal ions is obtained after the electrolysis is completed;

s12, adding a microbial deodorizing bacterial agent into the sewage with heavy metal ions removed after the treatment in the step S11, and stirring and reacting for 3-6 hours to obtain sewage A.

By adopting the technical scheme, the heavy metal removal effect is remarkable, the treatment time is short, the treatment condition is mild, and the industrial application is convenient.

Further, in the step S11, the electrolysis voltage is 15.0V to 20.0V, and the electrolysis time is 3 to 6 hours.

Further, the microbial deodorant in the step S12 contains any one or more of alcaligenes faecalis, a nucleophilic bacterium, bacillus coli and trichoderma koningii.

Preferably, in the step S2, the mass ratio of the sewage a to the component B is 100:0.5:0.25.

preferably, in the ultrasonic treatment in the step S3, the frequency of the ultrasonic wave is 20 to 40kHz.

Preferably, in step S4, the high-voltage electronic pulse technique is used, and the process parameters are as follows: the pulse voltage is 20-50 kV, the pulse frequency is 200-400 kHz, and the treatment time is 0.1-10 s.

Preferably, the temperature of natural drying in the step S5 is 20-30 ℃, and the time of natural drying is 10-72 hours.

Further, the auxiliary fuel in the step S6 is selected from any one or two of biomass fuel raw materials and carbon black slurry.

Further, the preparation method of the biomass fuel raw material comprises the following steps:

a. naturally drying the biomass raw material until the water content is less than or equal to 15%;

b. and (3) crushing the biomass raw material with the water content less than or equal to 15% to the particle size less than or equal to 5mm to obtain the biomass fuel raw material.

Further, the biomass fuel raw material is selected from any one or more of straw, rice husk, corncob, dregs, waste branches of fruit trees, edible fungus dregs, palm shell and palm silk generated in the processing process of agricultural and sideline products

Furthermore, the carbon black slurry is prepared from the carbon black cake which is common waste material in factories, and the carbon black slurry is produced by using the carbon black cake, so that the cost can be remarkably reduced

Compared with the prior art, the invention has the beneficial effects that: the invention has simple process, no secondary pollution and convenient realization of industrialized popularization and application; according to the invention, the sewage modified conditioner is used for oxidizing and nitrifying organic matters with muddy and high internal water bacterial groups in the sewage, so that the combustion performance of main organic matters in the sludge is greatly improved, and meanwhile, microorganisms in the sewage are used for breaking walls, so that moisture in a cell membrane is rapidly heated and evaporated in the oxidizing and nitrifying process, the cost of subsequent sludge drying is reduced, and the drying effect of the subsequent sludge is improved; the extracellular polymer and the cell wall in the sewage are destroyed by the strong oxidizing property of the ozone, the ozone is introduced into the sewage in the form of ozone micro-nano bubbles, the specific surface area of the ozone bubbles is greatly increased, the gas-water contact area is increased, and meanwhile, the residence time of the micro bubbles in the water is prolonged, so that the mass transfer efficiency of a gas-liquid interface is enhanced; the cavitation core in the liquid phase is increased by the ozone micro-nano bubbles, and the ozone micro-nano bubbles and ultrasonic wave cooperate to improve the separation efficiency and effect of the oil phase in the sewage; the instant high-voltage pulse electric field generated instantaneously between the two electrodes is acted on the sewage C by the high-voltage electronic pulse technology to dissolve out intracellular substances, thereby achieving the purpose of destroying microorganism cells and greatly reducing the water content of the sludge by mechanical dewatering; the calorific value of the sludge-derived clean fuel can be further increased by adding an auxiliary fuel to the dewatered sludge.

Drawings

FIG. 1 is a process flow diagram of a method for preparing a sludge derived clean fuel in accordance with the present invention;

FIG. 2 is a process flow diagram of a method for preparing a biomass fuel feedstock in accordance with the present invention;

FIG. 3 is a graph showing the falling strength trend in test example 1;

FIG. 4 is a graph showing the thermal stability trend in test example 1;

FIG. 5 is a plot of drop intensity trend in test example 2;

FIG. 6 is a graph showing the thermal stability tendency in test example 2.

Detailed Description

The invention is further described with reference to the following detailed description in order to make the technical means, the inventive features, the achieved objects and the effects of the invention easy to understand.

Example 1

Referring to fig. 1, the present embodiment provides a method for preparing a sludge derived clean fuel, comprising the steps of:

s1, pretreating sewage containing sludge, and removing peculiar smell of the sewage and heavy metal ions contained in the sludge to obtain sewage A;

s2, adding a sewage modification conditioner into the sewage A treated in the step S1, uniformly mixing, and aging for 2 hours to obtain sewage B;

the sewage modification conditioner comprises a component A and a component B, wherein the mass ratio of the sludge A to the component B is 100:0.2:0.1; wherein, the component A consists of the following raw materials in parts by weight: 5 parts of hypochlorite, 8 parts of dichromate, 8 parts of chromate, 20 parts of copper nitrate, 20 parts of calcium nitrate and 25 parts of sodium nitrate, wherein the component B comprises the following raw materials in parts by weight: 3 parts of bacillus subtilis, 1 part of lactobacillus and 1.5 parts of aspergillus niger;

s3, introducing ozone micro-nano bubbles into the sewage B obtained after the treatment in the step S2, performing aeration through the ozone micro-nano bubbles to enable ozone to fully contact with the sewage B, performing ultrasonic treatment on the sewage B introduced with the ozone micro-nano bubbles, destroying extracellular polymers and cell walls in the sewage through strong oxidizing property of the ozone micro-nano bubbles, and separating an oil phase contained in the sewage B through synergistic effect of the ozone micro-nano bubbles and ultrasonic waves to obtain sludge C; wherein the frequency of the ultrasonic wave is 35kHz;

s4, treating the sewage C treated in the step S3 by adopting a high-voltage electronic pulse technology, and then mechanically dehydrating until the water content is lower than 30% to obtain sludge; the technological parameters of the high-voltage electronic pulse technology in this embodiment are as follows: the pulse voltage is 40kV, the pulse frequency is 350kHz, the treatment time is 4s, and the distance between the polar plates is 6mm;

s5, adding auxiliary fuel into the sludge treated in the step S4, fully stirring and uniformly mixing to obtain a mixture, naturally drying the mixture until the water content is lower than 20%, and sending the mixture into a pressing machine for pressing and forming to obtain the sludge derived clean fuel; wherein, the mass ratio of the sludge and the auxiliary fuel obtained after the treatment in the step S4 is 25:10; wherein the natural drying temperature is 20-30 ℃, and the natural drying time is 10-24 hours.

Further, step S1 in the present embodiment includes the steps of:

s11, adjusting the pH value of the sewage containing the sludge to 4-5, and then adding ferric salt to obtain Fe in the sewage ³⁺ The concentration of the wastewater is 0.3g/L, the wastewater is stirred for 30 minutes and then is placed in an electrolytic cell, the power supply of the electrolytic cell is connected for electrolysis, and the wastewater for removing heavy metal ions is obtained after the electrolysis is completed; wherein the electrolysis voltage is 20.0V and the electrolysis time is 4.5 hours;

s12, adding a microbial deodorizing bacterial agent into the sewage from which the heavy metal ions are removed after the treatment in the step S11, and stirring and reacting for 5 hours to obtain sewage A; wherein the microbial deodorant contains alcaligenes faecalis, nucleophilic bacteria, bacillus megaterium and trichoderma koningii.

Further, the auxiliary fuel in step S6 in the present embodiment is a biomass fuel raw material and a carbon black slurry.

Further, referring to fig. 2, the preparation method of the biomass fuel raw material in this embodiment includes the following steps:

Further, the biomass fuel raw material in the embodiment is selected from straws generated in the processing process of agricultural and sideline products.

Example 2

s2, adding a sewage modification conditioner into the sludge A treated in the step S1, uniformly mixing, and aging for 2 hours to obtain sewage B; the sewage modified conditioner comprises a component A and a component B, wherein the mass ratio of the sewage A to the component B is 100:1.5:0.25; wherein, the component A consists of the following raw materials in parts by weight: 20 parts of hypochlorite, 20 parts of dichromate, 20 parts of chromate, 35 parts of copper nitrate, 38 parts of calcium nitrate and 41 parts of sodium nitrate, wherein the component B comprises the following raw materials in parts by weight: 6 parts of bacillus subtilis, 4 parts of lactobacillus and 5 parts of aspergillus niger;

s3, introducing ozone micro-nano bubbles into the sewage B obtained after the treatment in the step S2, performing aeration through the ozone micro-nano bubbles to enable ozone to fully contact the sewage B, performing ultrasonic treatment on the sewage B introduced with the ozone micro-nano bubbles, destroying extracellular polymers and cell walls of mud in the sewage through strong oxidizing property of the ozone micro-nano bubbles, and separating an oil phase contained in the sewage B through synergistic effect of the ozone micro-nano bubbles and ultrasonic waves to obtain sewage C; wherein the frequency of the ultrasonic wave is 40kHz;

s5, adding auxiliary fuel into the sludge treated in the step S4, fully stirring and uniformly mixing to obtain a mixture, naturally drying the mixture until the water content is lower than 20%, and sending the mixture into a pressing machine for pressing and forming to obtain the sludge derived clean fuel; wherein, the mass ratio of the sludge and the auxiliary fuel obtained after the treatment in the step S4 is 80:45; wherein the natural drying temperature is 20-30 ℃, and the natural drying time is 10-24 hours.

Further, step S1 in the present embodiment includes the steps of:

s11, adjusting the pH value of the sewage containing the sludge to 4-5, and then adding ferric salt to obtain Fe in the sewage ³⁺ The concentration of the wastewater is 0.5g/L, the wastewater is stirred for 30 minutes and then is placed in an electrolytic cell, the power supply of the electrolytic cell is connected for electrolysis, and the wastewater for removing heavy metal ions is obtained after the electrolysis is completed; wherein the electrolysis voltage is 16.0V, and the electrolysis time is 5 hours;

s12, adding a microbial deodorizing bacterial agent into the sewage from which heavy metal ions are removed after the treatment in the step S11, and stirring and reacting for 6 hours to obtain sewage A; the microbial deodorant contains alcaligenes faecalis, nucleophile, bacillus coli and trichoderma koningii.

b. and (3) crushing the biomass raw material with the water content less than or equal to 15% to the particle size less than or equal to 5mm to obtain the biomass fuel.

Further, the biomass fuel raw material in the embodiment is selected from straw, rice husk, corncob, medicine residues, waste branches of fruit trees, edible fungus residues, palm shells and palm whiskers generated in the processing process of agricultural and sideline products.

Example 3

s1, pretreating sewage containing sludge, and removing peculiar smell of the sludge and heavy metal ions contained in the sludge to obtain sewage A;

s2, adding a sewage modification conditioner into the sewage A treated in the step S1, uniformly mixing, and aging for 1.5 hours to obtain sewage B; the sewage modified conditioner comprises a component A and a component B, wherein the mass ratio of the sewage A to the component B is 100:0.5:0.25; wherein, the component A consists of the following raw materials in parts by weight: 15 parts of hypochlorite, 15 parts of dichromate, 12 parts of chromate, 20 parts of nitric acid, 29 parts of calcium nitrate and 28 parts of sodium nitrate, wherein the component B comprises the following raw materials in parts by weight: 4 parts of bacillus subtilis, 2 parts of lactobacillus and 2 parts of aspergillus niger;

s5, adding auxiliary fuel into the sludge treated in the step S4, fully stirring and uniformly mixing to obtain a mixture, naturally drying the mixture until the water content is lower than 20%, and sending the mixture into a pressing machine for pressing and forming to obtain the sludge derived clean fuel; wherein, the mass ratio of the sludge and the auxiliary fuel obtained after the treatment in the step S4 is 70:31; wherein the natural drying temperature is 20-30 ℃, and the natural drying time is 10-24 hours.

Further, step S1 in the present embodiment includes the steps of:

s11, adjusting the pH value of sewage containing sludge to 4-5, adding ferric salt, wherein the concentration of Fe < 3+ > in the obtained sewage is 0.6g/L, stirring for 30 minutes, placing the sewage in an electrolytic cell, switching on a power supply of the electrolytic cell, and carrying out electrolysis to obtain sewage with heavy metal ions removed after the electrolysis is completed; wherein the electrolysis voltage is 20.0V and the electrolysis time is 5 hours;

Further, the auxiliary fuel in step S6 in the present embodiment is either one or both of a biomass fuel raw material and a carbon black slurry.

Further, the biomass fuel raw material in the embodiment is straw.

Example 4

s2, adding a sewage modification conditioner into the sludge A treated in the step S1, uniformly mixing, and aging for 1.5 hours to obtain sewage B; the sewage modified conditioner comprises a component A and a component B, wherein the mass ratio of the sewage A to the component B is 100:0.5:1.5; wherein, the component A consists of the following raw materials in parts by weight: 15 parts of hypochlorite, 15 parts of dichromate, 12 parts of chromate, 20 parts of nitric acid, 29 parts of calcium nitrate and 28 parts of sodium nitrate, wherein the component B comprises the following raw materials in parts by weight: 4 parts of bacillus subtilis, 2 parts of lactobacillus and 2 parts of aspergillus niger;

Further, step S1 in the present embodiment includes the steps of:

s11, adding ferric salt after adjusting the pH value of the sewage to 4-5 to obtain Fe in the sewage ³⁺ The concentration of the wastewater is 0.6g/L, the wastewater is stirred for 30 minutes and then is placed in an electrolytic cell, the power supply of the electrolytic cell is connected for electrolysis, and the wastewater for removing heavy metal ions is obtained after the electrolysis is completed; wherein the electrolysis voltage is 20.0V and the electrolysis time is 5 hours;

Further, the biomass fuel raw material in the embodiment is straw.

Example 5

s1, pretreating sewage, and removing peculiar smell of the sewage and heavy metal ions contained in the sludge to obtain sewage A;

s2, adding a sewage modification conditioner into the sewage A treated in the step S1, uniformly mixing, and aging for 1.5 hours to obtain sludge B; the sewage modified conditioner comprises a component A and a component B, wherein the mass ratio of the sewage A to the component B is 100:0.5:0.1; wherein, the component A consists of the following raw materials in parts by weight: 15 parts of hypochlorite, 15 parts of dichromate, 12 parts of chromate, 20 parts of nitric acid, 29 parts of calcium nitrate and 28 parts of sodium nitrate, wherein the component B comprises the following raw materials in parts by weight: 4 parts of bacillus subtilis, 2 parts of lactobacillus and 2 parts of aspergillus niger;

Further, step S1 in the present embodiment includes the steps of:

s11, adjusting the pH of sewage containing sludgeAdding ferric salt after finishing to 4-5, and obtaining Fe in sewage ³⁺ The concentration of the wastewater is 0.6g/L, the wastewater is stirred for 30 minutes and then is placed in an electrolytic cell, the power supply of the electrolytic cell is connected for electrolysis, and the wastewater for removing heavy metal ions is obtained after the electrolysis is completed; wherein the electrolysis voltage is 20.0V and the electrolysis time is 5 hours;

Further, the biomass fuel raw material in the embodiment is straw.

Example 6

s1, pretreating sewage, and removing peculiar smell of the sewage and heavy metal ions contained in the sewage to obtain sewage A;

s5, adding auxiliary fuel into the sludge treated in the step S4, fully stirring and uniformly mixing to obtain a mixture, naturally drying the mixture until the water content is lower than 20%, and sending the mixture into a pressing machine for pressing and forming to obtain the sludge derived clean fuel; wherein, the mass ratio of the sludge and the auxiliary fuel obtained after the treatment in the step S4 is 70:10; wherein the natural drying temperature is 20-30 ℃, and the natural drying time is 10-24 hours.

Further, step S1 in the present embodiment includes the steps of:

s11, adjusting the pH value of the sewage containing the sludge to 4-5, and then adding ferric salt to obtain Fe in the sewage ³⁺ The concentration of the wastewater is 0.6g/L, the wastewater is stirred for 30 minutes and then is placed in an electrolytic cell, the power supply of the electrolytic cell is connected for electrolysis, and the wastewater for removing heavy metal ions is obtained after the electrolysis is completed; wherein the electrolysis voltage is 20.0V and the electrolysis time is 5 hours;

Further, the biomass fuel raw material in the embodiment is straw.

Example 7

s5, adding auxiliary fuel into the sludge treated in the step S4, fully stirring and uniformly mixing to obtain a mixture, naturally drying the mixture until the water content is lower than 20%, and sending the mixture into a pressing machine for pressing and forming to obtain the sludge derived clean fuel; wherein, the mass ratio of the sludge and the auxiliary fuel obtained after the treatment in the step S4 is 70:45; wherein the natural drying temperature is 20-30 ℃, and the natural drying time is 10-24 hours.

Further, step S1 in the present embodiment includes the steps of:

s11, adjusting the pH value of the sewage to 4-5, adding ferric salt, wherein the concentration of Fe < 3+ > in the obtained sewage is 0.6g/L, stirring for 30 minutes, placing the sewage in an electrolytic cell, switching on a power supply of the electrolytic cell, and carrying out electrolysis to obtain the sewage with heavy metal ions removed after the electrolysis is completed; wherein the electrolysis voltage is 20.0V and the electrolysis time is 5 hours;

s12, adding a microbial deodorizing bacterial agent into the sewage from which heavy metal ions are removed after the treatment in the step S11, and stirring and reacting for 6 hours to obtain sewage A; wherein the microbial deodorant contains one or more of alcaligenes faecalis, a nucleophilic bacterium, bacillus megaterium and trichoderma koningii.

Further, the biomass fuel raw material in the embodiment is straw.

Test example 1

The prepared sludge-derived clean fuel described in example 3 was labeled as sample 1, the prepared sludge-derived clean fuel described in example 4 was labeled as sample 2, and the prepared sludge-derived clean fuel described in example 5 was labeled as sample 3. The difference between the sample 3, the sample 4 and the sample 5 is that the proportion of the component A and the component B in the sewage modified conditioner in the preparation process is different. In the test example, the falling strength and the thermal stability are taken as evaluation indexes, and the influence of the proportion of the component A and the component B on the preparation process of the sludge derived clean fuel is examined.

FIG. 3 is a plot of drop intensity trend plotted on the abscissa of the ratio of component A to component B in the wastewater-modified conditioner, and on the ordinate of the values of drop intensity at different ratios of component A to component B;

fig. 4 is a graph of thermal stability trend plotted on the abscissa of the ratio of component a to component B in the sewage-modified conditioner, and on the ordinate of the values of thermal stability at different ratios of component a to component B.

Test example 2

The sludge-derived clean fuel prepared as described in example 6 was labeled as sample 4, and the sludge-derived clean fuel prepared as described in example 7 was labeled as sample 5. Sample 3, sample 4 and sample 5 differ in the mass ratio of sludge E to auxiliary fuel during the preparation process. In the test example, the falling strength and the thermal stability are taken as evaluation indexes, and the influence of the mass ratio of the sludge E to the auxiliary fuel on the preparation process of the sludge derived clean fuel is examined.

FIG. 5 is a falling strength trend graph plotted on the abscissa of the mass ratio of sludge E to auxiliary fuel in the sewage-modified conditioner, and on the ordinate of the values of falling strengths of different mass ratios of sludge E to auxiliary fuel;

FIG. 6 is a graph of thermal stability trend plotted on the abscissa of the mass ratio of sludge E to auxiliary fuel in the sewage-modified conditioner, and on the ordinate of the thermal stability value at the mass ratio of sludge E to auxiliary fuel;

analysis of test results: as can be seen from fig. 3, 4, 5 and 6, the mass ratio of the sludge E to the auxiliary fuel has a significant effect on the falling strength and thermal stability of the sludge-derived clean fuel, mainly because the mass ratio of the sludge/the auxiliary fuel directly determines the moisture in the mixed material, the moisture is not only the lubricant in the process of forming the sludge-derived clean fuel, but also reduces the internal friction of the forming system, and improves the strength and thermal stability of the sludge-derived clean fuel; when the water content is excessive, poor contact can be generated between the sludge and the auxiliary fuel, so that the compressive strength and the thermal stability of the sludge derived clean fuel are reduced; when the water content is too small, the sludge derived fuel is transported inside the sludge derived fuel because the inter-particle sliding is not easy to occur during the compression of the sludge derived fuel, and the falling strength is reduced.

Test example 3

The difference between the preparation method of the sludge derived clean fuel in comparative example 1 and example 3 is that: in comparative example 1, no sewage modifying conditioner was added, and the other steps and process parameters were the same as in example 3; the sludge-cleaning derived fuel prepared in comparative example 1 was labeled as sample 6.

Under laboratory conditions, sample 3 and sample 6 are compared, the ignition temperature of sample 3 is reduced by 55 ℃ compared with sample 6, the combustion speed is improved by nearly 1.8 times, the combustion efficiency is improved by 15%, and the sewage modified conditioner greatly improves the performance of the sludge derived clean fuel.

Although embodiments of the present invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made therein without departing from the principles and spirit of the invention, the scope of which is defined in the appended claims and their equivalents.

Claims

1. A method for preparing a sludge-derived clean fuel, comprising the steps of:

s1, pretreating sewage containing sludge, and removing peculiar smell of the sewage and heavy metal ions contained in the sewage to obtain sewage A;

s2, adding a sewage modification conditioner into the sewage A treated in the step S1, uniformly mixing, and aging for 1-2.5 hours to obtain sewage B; the sewage modified conditioner comprises a component A and a component B, wherein the mass ratio of the sewage A to the component B is 100:0.5:0.25; wherein the component A consists of the following raw materials in parts by weight: 5-20 parts of hypochlorite, 8-20 parts of dichromate, 8-20 parts of chromate, 20-35 parts of copper nitrate, 20-38 parts of calcium nitrate and 25-41 parts of sodium nitrate, wherein the component B comprises the following raw materials in parts by weight: 3 to 6 parts of bacillus subtilis, 1 to 4 parts of lactobacillus and 1.5 to 5 parts of aspergillus niger;

s3, introducing ozone micro-nano bubbles into the sewage B obtained after the treatment in the step S2, performing aeration through the ozone micro-nano bubbles to enable ozone to fully contact with the sewage B, performing ultrasonic treatment on the sewage B introduced with the ozone micro-nano bubbles, destroying extracellular polymers and cell walls in the sewage through strong oxidization of the ozone micro-nano bubbles, and separating an oil phase contained in the sewage B after the treatment of the ozone micro-nano bubbles and ultrasonic waves to obtain sewage C;

2. The method for preparing a sludge derived clean fuel as claimed in claim 1, wherein the step S1 comprises the steps of:

s11, adjusting the pH value of sewage containing sludge to 4-5, adding ferric salt, wherein the concentration of Fe < 3+ > in the obtained sewage is 0.2-0.6 g/L, stirring for 20-30 minutes, placing the sewage in an electrolytic cell, switching on a power supply of the electrolytic cell, and carrying out electrolysis to obtain sewage for removing heavy metal ions after the electrolysis is completed;

3. The method for preparing a sludge derived clean fuel as claimed in claim 2, wherein in the step S11, the electrolysis voltage is 15.0V to 20.0V and the electrolysis time is 3 to 6 hours.

4. The method for preparing a sludge-derived clean fuel as claimed in claim 2, wherein the microbial deodorant in the step S12 contains one or more of alcaligenes faecalis, nucleophile, bacillus megaterium and trichoderma koningii.

5. The method for preparing a sludge derived clean fuel as claimed in claim 1, wherein the ultrasonic wave in the step S3 has a frequency of 20 to 40kHz.

6. The method for preparing a sludge derived clean fuel as claimed in claim 1, wherein the high voltage electronic pulse technique in step S4 has the following process parameters: the pulse voltage is 20-50 kV, the pulse frequency is 200-400 kHz, and the treatment time is 0.1-10 s.

7. The method for preparing a sludge derived clean fuel as claimed in claim 1, wherein the natural drying temperature in the step S5 is 20-30 ℃ and the natural drying time is 10-24 hours.

8. The method for producing a sludge derived clean fuel as claimed in claim 1, wherein the auxiliary fuel in the step S5 is selected from any one or both of biomass fuel raw material and carbon black slurry; wherein the biomass fuel raw material is selected from any one or more of straw, rice husk, corncob, dregs, waste branches of fruit trees, edible fungus dregs, palm shells and palm whiskers generated in the processing process of agricultural and sideline products.

9. The method for preparing a sludge derived clean fuel as claimed in claim 8, wherein the method for preparing the biomass fuel raw material comprises the following steps: