CN1320084C - Extra fine mud fuel and production thereof - Google Patents

Abstract

The invention provides an ultrafine sludge fuel and a production method thereof. The sludge fuel contains: (a) 30-80 parts by weight of water-containing sludge; (b) 0.001-50 parts by weight of pulverized coal; and (c) 10-70 parts by weight of fuel oil; wherein, The average particle size of solid particles is below 20 microns. The sludge fuel of the invention is a fuel slurry that can be pumped, can be atomized and burned, has a high burn-off rate and minimal pollution, and is a clean fuel with low cost.

Description

A kind of superfine sludge fuel and its production method

technical field

The invention relates to the fields of environmental protection and fuel processing, and more particularly relates to an ultrafine sludge fuel and a production method thereof.

Background technique

The sludge formed by the treatment of sewage in urban sewage treatment plants contains a large amount of combustible organic substances, as well as toxic organic substances, a large number of pathogens and some heavy metals, so it needs special treatment.

Landfilling of these sewage sludges has been banned or is about to be banned in North America, Europe and Japan. The use of sludge as compost will also be gradually banned by legislation, because these methods cannot fundamentally eliminate pollution. Landfill will cause heavy metal elements and harmful chemicals to pollute groundwater with the infiltration of surface water, and use them as fertilizers. Heavy metal elements in sludge will be absorbed by plants and then enter the bodies of animals and humans.

Another way to deal with sludge is incineration, which is currently widely used. However, the conventional incineration method has various disadvantages. The main disadvantage is that the sludge and auxiliary fuels are incompletely burned, and there are still pollutants discharged. For example, dioxin-like compounds with strong carcinogenic effects exist in the flue gas of general incinerators, and heavy metals in ash It is still possible to pollute the environment.

Various technologies exist for converting sludge to fuel for the purpose of complete combustion, including:

(1) Mix the mechanically dewatered sludge (water content between 30% and 90%, mostly between 50% and 80%) with powdered coal and a certain amount of additives, dry and press the briquette. For example, Chinese patent application 02133390.4, Chinese patent application 00123028.X, Chinese patent application 99112394.8, Chinese patent application 94112288.3, etc. The advantage of this method is that the process is simple, the investment in equipment is small, and the cost is low. However, the solid briquette is difficult to burn completely, the utilization rate of calorific value is low, and the heavy metals in the ash are difficult to handle.

(2) Mix dewatered sludge with pulverized coal, extrude, granulate and dry into granular fuel, which can be used as auxiliary fuel for power plants. Such as European patent application EP 0643124A1, U.S. patent 05797972A, U.S. patent 05711768A, Japanese patent (publication number) 59170198A, Japanese patent (publication number) 60082192A, etc. The advantage of this type of method is that the fuel has a high calorific value, but the drying process requires a lot of equipment and energy, which significantly increases the production cost.

(3) After the dewatered sludge is further dehydrated and dried, it is pulverized into powdered fuel and used as boiler fuel, such as patent EP049620A2, Japanese patent (publication number) 2001300590A, etc. The advantage of this type of method is that the process is simple, but drying sludge requires a lot of heat energy, which increases the cost, and the pure sludge fuel has a low calorific value.

(4) After mixing the dewatered sludge and coal powder, heating at high temperature in isolation from the air, degassing, and preparing synthesis gas and fuel gas. The remaining solids still contain combustible carbides, which can be used as mixed fuels after being mixed with other fuels. Such as patent DE 19925565A1, US4378229A, US 05211723A, US 05217625, Chinese patent application 99814537.8, Chinese patent application 93101893.5, patent DE 3640181A1, Japanese patent (publication number) JP10113697 19980506, etc. This type of method has complex process technology, requires more equipment, and costs too much.

(5) After the dewatered sludge is mixed with solid carbon-containing fuel (such as coal) and liquid carbon-containing fuel (such as oil), it is heated at high temperature to generate gas or directly used as fuel. Such as US05788721A, EP01112971A1, Japanese patent (publication number) JP 11005100 19990112, Japanese patent (publication number) JP 10328698 19981215, Japanese patent (publication number) 06246297A, Japanese patent (publication number) 2000176490A, Japanese patent (publication number) 209027 Japan 159 Patent (publication number) 56056283A and so on. The disadvantage of this type of method is the same as that of (4) type method, the equipment is many and complicated, and the cost is high.

In addition, the common disadvantages of the methods (1) to (5) above are that the solid particles in the fuel are too thick to burn completely, and there are still many pollutants in the flue gas, so clean combustion has not been realized. Sometimes in order to make the mixed fuel slurry stable, also add stabilizer, as Japanese Patent (publication number) 55139494A, Japanese patent (publication number) 55139495A and Japanese patent (publication number) 55142092A etc.

To sum up, in order to effectively treat wastewater sludge, there is an urgent need in this field to develop new clean-burning, low-cost sludge fuels and their preparation methods.

Contents of the invention

The object of the present invention is to provide a sludge fuel with clean combustion and low cost and its preparation method.

In the first aspect of the present invention, a kind of sludge fuel is provided, and it contains:

(a) the aqueous sludge of 30-80 parts by weight;

(b) 0.001-50 parts by weight of pulverized coal;

(c) fuel oil of 10-70 parts by weight;

Wherein, the average particle size of the solid particles is below 20 microns.

In another preferred example, the average particle size of the solid particles is 0.1-20 microns.

In another preferred example, the average particle size of the solid particles is 0.5-10 microns.

In another preferred example, the water content of the water-containing sludge is 30-90wt%.

In another preferred example, the dry basis calorific value of the aqueous sludge is 2000 kcal/kg-3500 kcal/kg.

In another preferred example, the water-containing sludge is selected from the following group: domestic sludge produced by urban domestic sewage treatment plants, paper mill sludge produced by wastewater treatment in paper mills, industrial sludge produced by industrial enterprise sewage treatment, Oily sludge, or mixtures thereof.

In another preferred embodiment, the pulverized coal is selected from the group consisting of lignite, bituminous coal and anthracite, coke, coke chips, washed coal and washed waste coal, or a mixture thereof.

In another preferred example, the fuel oil is selected from the group consisting of diesel oil, heavy diesel oil, heavy oil, residual oil, petroleum crude oil, heavy crude oil, shale oil, petroleum coke, petroleum pitch, coal tar, waste fuel oil, Waste cooking oil, waste industrial oil, pyrolysis oil of polymer substances or their mixtures.

In another preferred embodiment, it also contains a desulfurizing agent, and the amount of the desulfurizing agent is such that the gram-atom ratio of the calcium or magnesium in the desulfurizing agent to the sulfur in the fuel is between 1.0:1 and 6:1.

In a second aspect of the present invention, a method for preparing sludge fuel is provided, the method comprising the following steps:

(i) mixing (a) 30-80 parts by weight of water-containing sludge, (b) 0.001-50 parts by weight of coal powder, and (c) fuel oil of 10-70 parts by weight to form a raw material mixture,

(ii) Grinding the raw material mixture so that the average particle diameter of the solid particles in the fuel is less than 20 microns, thereby obtaining slurry-like sludge fuel;

Or the method includes the steps:

(a) 30-80 parts by weight of water-containing sludge (b) 0.001-50 parts by weight of pulverized coal and (c) 10-70 parts by weight of fuel oil are simultaneously fed into grinding equipment for grinding, so that the fuel The average particle size of the solid particles is less than 20 microns, so as to obtain slurry-like sludge fuel.

Detailed ways

The inventor has found through in-depth and extensive research that: the raw material mixture formed by mixing water-containing sludge, coal powder and fuel oil, after ultra-fine grinding and homogenization, when the average particle size of the solid particles is below 20 microns, a A new type of slurry fuel with oil as the continuous phase and sludge and coal powder as the dispersed phase. In this slurry fuel, the slurry fuel is very stable because the particles are fine and evenly distributed. And because the ultrafine particles in the fuel are separated by an oil film, they are easy to disperse and atomize, so that the combustion is very complete, and the carbon monoxide and unburned carbon particles in the flue gas are greatly reduced. Its molten slag wraps heavy metals in it, preventing secondary pollution caused by heavy metal leaching, so this slurry fuel is a clean fuel. The present invention has been accomplished on this basis.

As used herein, the terms "fuel of the present invention", "fuel composition of the present invention", "sludge fuel of the present invention", "sludge fuel composition of the present invention" are used interchangeably and refer to Sludge, coal powder and fuel oil, and the average particle size of solid particles is 20 microns or less.

The ultra-fine sludge fuel of the present invention contains water-containing sludge from a sewage treatment plant, coal and fuel oil, wherein the oil is a continuous phase, and the sludge and its contained water and coal powder are a dispersed phase. The average particle size of the solid particles contained in the fuel is less than 20 microns, preferably less than 10 microns, more preferably less than 5 microns. Because water-containing sludge contains 30% to 90% of water, so the superfine sludge fuel of the present invention contains a certain amount of water, the presence of water can improve combustion, so that the carbon particles in the fuel and the organic matter in the combustion process The charcoal particles formed by the cracking are burned out, realizing the complete combustion of the fuel.

Aqueous sludge

Aqueous sludge usable in the present invention is not particularly limited. Representative examples include (but are not limited to): domestic sludge produced by municipal sewage treatment plants, paper mill sludge produced by wastewater treatment in paper mills, industrial sludge produced by sewage treatment in industrial enterprises, oil sludge, or various A mixture of sludge.

The water content of these kinds of sludge is generally between 30% and 90%, and most of them are between 50% and 80%. One of the differences between the present invention and the existing technology is that the water-containing sludge does not need to be further dried, which not only saves the energy required for drying, but also saves the equipment required for drying, which significantly reduces the production cost.

Usually, the dry basis calorific value of these sludges is between 2000 kcal/kg and 3500 kcal/kg, most of which are around 3000 kcal/kg. These sludges contain more organic volatile components and less carbon, and the volatile components in combustibles are between 40% and 80%.

The amount of hydrous sludge in the superfine sludge fuel of the present invention can be between 30% and 80%, generally between 40% and 60%, calculated according to the total weight of fuel sludge. If expressed in parts by weight, the amount of the water-containing sludge can be between 30 and 80 parts by weight, generally between 40 and 60 parts by weight.

pulverized coal

Coal usable in the present invention is not particularly limited as long as it is pulverized coal. Representative examples include (but are not limited to): low-grade coals such as lignite, bituminous and anthracite coal, coke, coke dust, washed coal and washed waste coal, or mixtures of the above coals.

The amount of coal powder in the present invention can be between 0.001% and 50%, generally between 15% and 40%, based on the total weight of fuel sludge. If expressed in parts by weight, the amount of pulverized coal can be between 0.001 and 50 parts by weight, generally between 15 and 40 parts by weight. When the dry basis calorific value of the water-containing sludge is particularly high, or the content of fuel oil is high, coal powder may not be added.

fuel oil

The fuel oil that can be used in the present invention is not particularly limited, and representative examples include (but are not limited to): diesel oil, heavy diesel oil, heavy oil, residual oil, petroleum crude oil, heavy crude oil, shale oil, petroleum coke, petroleum asphalt, coal Tar, waste fuel oil, waste cooking oil, waste industrial oil, polymer pyrolysis oil. It can also be a mixture of two or more oils mentioned above.

The amount of fuel oil in the present invention can be between 10% and 70%, generally between 20% and 50%, based on the total weight of fuel sludge. If expressed in parts by weight, the amount of fuel oil can be between 10 and 70 parts by weight, generally between 20 and 50 parts by weight.

extra ingredients

Various conventional additives, such as desulfurizers, can also be added to the sludge fuel of the present invention. The content of these additional additives can be conventionally used, usually 0.1-10 parts by weight, preferably 0.2-6 parts by weight.

The desulfurizer added in the process of sludge fuel production can be limestone, dolomite and lime and other organic or inorganic substances containing calcium or magnesium or a mixture of these substances. The desulfurizing agent described in the present invention can be without superfine grinding (such as a desulfurizing agent with an average particle size greater than 20 microns), but the preferred desulfurizing agent is through superfine grinding, and its average particle size is below 20 microns. , which can further improve the sulfur removal effect. Lime slurry can also be used as a desulfurizer.

In the present invention, the consumption of desulfurizer is controlled in the gram atom ratio (such as calcium: sulfur) of the calcium or magnesium in the desulfurizer and the sulfur in the fuel between 1.0: 1～6: 1, preferably calcium: sulfur is at 3.0 : between 1 and 5:1.

When the desulfurizer is added, most of the sulfur in the fuel can be solidified in the ash in the form of sulfate and sulfite during the combustion process, thereby greatly reducing the emission of sulfur dioxide in the flue gas.

Preparation

The invention also provides a production method of superfine sewage sludge fuel.

The production method of sludge fuel of the present invention comprises steps:

(i) (a) 30-80 parts by weight of water-containing sludge, (b) coal powder of 0.001-50 parts by weight, (c) fuel oil of 10-70 parts by weight and (d) optional Additional ingredients (such as desulfurizers) are mixed to form a raw material mixture,

(ii) Grinding the raw material mixture so that the average particle size of the solid particles in the fuel is 20 microns or less to obtain slurry-like sludge fuel.

In another preferred example, the method comprises the steps of: mixing (a) 30-80 parts by weight of aqueous sludge (b) 0.001-50 parts by weight of coal powder and (c) 10-70 parts by weight of fuel At the same time, the oil is sent to the grinding equipment for grinding, so that the average particle size of the solid particles in the fuel is less than 20 microns, so as to obtain slurry-like sludge fuel.

The grinding method is not particularly limited, and may be an existing ultrafine grinding or pulverizing method in the art, as long as it can make the particle size of the solid particles in the fuel reach the desired size.

In a preferred example of the present invention, water-containing sludge, pulverized coal and fuel oil are added in a certain proportion to the rotating pulsating ultrafine particle powder dissolving machine (hereinafter referred to as "mixing ultrafine particle dissolving machine" produced by Shanghai Fine Micro Powder Dissolving Machinery Equipment Co., Ltd.) Fine Grinder") (Chinese Patent Application No.: 01109394.3) is mixed and ultra-finely ground into a slurry fuel, so that the particle size of the solid particles in the fuel reaches the required size.

When the raw material composition is ground to a very small solid particle size (that is, the average particle size is below 20 microns, mostly below 10 microns), the tiny particles of oil, organic matter, water and coal in the sludge fuel can be very uniform Ground distribution, stable state, and certain fluidity, can be pumped.

At the same time, the ultra-fine sludge fuel formed by the above method can be burned completely through atomization, and its emissions of sulfur dioxide, nitrogen oxides, carbon monoxide and black smoke are significantly reduced compared with coal and heavy fuel oil, which is a kind of clean fuel.

The production method of the present invention can be continuous or batch. The preferred mode is continuous. A preferred production method is to feed the water-containing sludge, pulverized coal and fuel oil produced by the sewage treatment plant into the mixing ultra-fine grinding machine through the metering device according to the required ratio, and carry out mixed ultra-fine grinding. Realize continuous production. In addition, according to the needs, the material can be ground multiple times, or two or more sets of mixed ultra-fine grinding equipment can be used in series to obtain finer and more uniformly mixed sludge fuel.

In addition, the production of ultra-fine sludge fuel can also be carried out step by step, that is, pulverized coal and fuel oil are mixed and ground to form oil-coal slurry, and then mixed with sludge for ultra-fine grinding to produce sludge fuel. It is also possible to mix and grind water-containing sludge and fuel oil to form sludge oil slurry, and then mix sludge oil slurry and coal powder for ultra-fine grinding to produce ultra-fine sludge fuel. The production of sludge fuel by step mixing and superfine grinding can also be continuous or intermittent. The preferred method is continuous, because it does not affect production efficiency.

Because fuel oil, especially heavy fuel oil, has high viscosity and poor fluidity at relatively low temperatures, the temperature of the material during production can be higher than room temperature, controlled between 15 degrees Celsius and 95 degrees Celsius, generally between 50 and 80 degrees Celsius .

When the desulfurizer is added, the desulfurizer should be mixed together with water-containing sludge, coal powder and fuel oil for ultra-fine grinding, and the average particle size of the desulfurizer in the fuel can also be achieved below 20 microns, preferably below 10 microns s level.

The main advantages of the present invention are:

(a) The process flow of the present invention is short, and the equipment is relatively simple. After the sludge is mechanically dehydrated, no further drying is required, which saves energy and reduces equipment.

(b) The feedstock mixture is ultrafinely ground to form a pumpable fuel slurry. In addition, the sludge fuel of the present invention can be atomized and burned, has a high burn-off rate and minimal pollution, and is a clean fuel.

Below in conjunction with specific embodiment, further illustrate the present invention. It should be understood that these examples are only used to illustrate the present invention and are not intended to limit the scope of the present invention. For the experimental methods without specific conditions indicated in the following examples, the conventional conditions or the conditions suggested by the manufacturer are usually followed.

Example 1

1. Raw material

(1) Domestic sludge produced by a sewage treatment plant in Shanghai

Water content---74.0%, calorific value (received basis, kcal/kg)---910

(2) Power coal powder of a coal mine

Water content ---9.0%, ash content ---17%, calorific value (kcal/kg) ---5500

Coal powder particle size (mm)---2～5

(3) Heavy oil (180#)

Density (15 degrees Celsius, kg/L) --- 0.9680

Viscosity (England) E 80---6.13, calorific value (kcal/kg)---10500

(4) Commercially available light precipitated calcium carbonate

Calcium carbonate content: ≥97%

Average particle size (micron): 1~3

2. Preparation conditions

(1) Raw material ratio (parts by weight)

Aqueous sludge---40

Pulverized coal---30

Heavy oil (180#)---30

Calcium carbonate (gram atomic ratio, calcium: sulfur) --- 3:1

(2) Preparation method

Mixing and grinding method---Materials are simultaneously sent to a mixing ultrafine grinder (Shanghai Jingwei Powder Rong Machinery Equipment Co., Ltd., CN01109394.3) for grinding once.

Material temperature (Celsius)

Heavy oil --- 50, other solid materials --- room temperature.

3. Product sludge fuel index

(1) Appearance --- gray black fuel slurry, with certain fluidity, can be pumped

(2) Water content (weight%)---32.3

(3) Average particle size of solid particles in fuel (microns)---15.1

[Note: The particle size analysis of raw materials and sludge fuel in the present invention uses a laser particle size analyzer. The light source of the instrument is a helium-neon laser with a wavelength of 0.6328μm and a power of 2mW. The samples were diluted with gasoline, and gasoline was used as the medium. Using the light scattering theory of particles, the particle size is different, the scattering angle is also different, the intensity of scattered light is measured at different scattering angles, and the average particle size and distribution of the particles are given by computer processing. The average particle size here is taken as the particle size of 50% of the cumulative distribution, the same as in the following examples. ]

(4) Calorific value (received basis, kcal/kg)---4635

(5) Sulfur content (dry basis, weight%)---3.27

(6) Ash content (dry basis, weight%)---23.90

(7) Sulfur trioxide content in ash (weight %)---24.50

The proportion of sulfur fixed in the ash to the sulfur in the fuel (weight %)---71.5.

Example 2

1. Raw materials

(1) Wastewater sludge from a paper mill in Shanghai

Water content (weight%)---60.0, calorific value (received basis, kcal/kg)---939

(2) pulverized coal---indicator is the same as embodiment 1

(3) heavy oil---indicator is the same as embodiment 1

(4) Commercially available powdered quicklime

Particle size: about 1mm

Calcium oxide content: >86%

2. Preparation conditions

(1) Raw material ratio (parts by weight)

Papermaking sludge---40

Pulverized coal---30

Heavy oil---30

Commercially available powdered quicklime --- (gram atomic ratio, calcium: sulfur) --- 4:1

(2) Preparation method

First mix and grind the sludge and heavy oil in a mixer grinder, then mix and grind the mixture of sludge and oil with coal powder and lime powder in a mixer grinder to form a slurry mixture, and then grind the slurry mixture twice.

Material temperature (Celsius):

Heavy oil --- 80, other materials --- room temperature

3. Product sludge fuel index

The appearance shape and various combustion indexes of the prepared sludge fuel were measured by conventional methods. The result is as follows:

(1) Appearance --- gray black fuel slurry, with certain fluidity, can be pumped

(2) Water content (weight%)---44.1

(3) Average particle size of solids in fuel slurry (micron)---4.5

(4) Sulfur content (weight%)---1.7

(5) Ash content (dry basis, weight%)---21.71

(6) Calorific value (kcal/kg)---4301

(7) Sulfur trioxide in ash (weight%)---27.71

The proportion of sulfur fixed in the ash to the sulfur in the fuel (weight %)---79.5.

Example 3

1. Raw materials

(1) Industrial sludge from a chemical company in Shanghai

Water content (weight%)---8 5

Calorific value (dry basis, kcal/kg)---3305

(2) No. 1 clean coal in a coal mine

Water content (weight%)---9.5

Ash content (weight%)---less than 7.8

Calorific value (kcal/kg)---6650

Granularity (mm) 2～5

(3) Heavy oil 380#

Density (kg/L, 15°C)---0.9562

Viscosity (England) E 80---10.02

Calorific value (kcal/kg)---10112

(4) Commercially available calcium carbide slag powder

Particle size (mm): 1~2.  Calcium oxide content: >90%

2. Preparation conditions

(1) Raw material ratio (parts by weight)

Industrial sludge---50

Pulverized coal---20

Heavy oil---30

Carbide slag (gram atomic ratio, calcium: sulfur) --- 5:1

(2) Mixing method --- first mix and grind heavy oil and coal powder, and then mix and grind with industrial sludge and carbide slag. Two mixing ultrafine grinders (manufactured by Shanghai Fine Powder Dissolution Machinery Equipment Co., Ltd.) are used in series. The mixture was ground two more times.

(3) Material temperature (Celsius)

380# heavy oil --- 95, other materials --- room temperature

3. Product sludge fuel index

(1) Appearance --- gray black fuel slurry, with certain fluidity, can be pumped

(2) Average particle size of solids in fuel slurry (micron)---4.1

(3) Water content (weight%)---44.3

(4) Calorific value (received basis, kcal/kg)---4537

(5) Sulfur content (received basis, weight %)---.1.12

(6) Ash content (received basis, weight %)---11.2

(7) Sulfur trioxide in ash (weight %)---22.5

The ratio of sulfur fixed in ash to fuel sulfur (%)---90.1

Example 4

1. Raw material

Domestic sludge --- same as embodiment 1

coal tar

Density (kg/L, 15°C)---0.9653

Viscosity (England) E 80---9.5

Calorific value (kcal/kg)---9726

Commercially available ground calcium carbonate

Calcium carbonate content: >98%

Particle size (micron): <20

2. Preparation conditions

(1) Raw material ratio (parts by weight)

Sludge---70

Coal tar---30

Heavy calcium carbonate (gram atomic ratio, calcium: sulfur) --- 1.5:1

(2) Preparation method

Mixing and grinding method---send the three materials directly into the mixing and grinding machine in proportion

Mixing and grinding, 2 sets of mixing and grinding machines connected in series

Material temperature (Celsius)

Coal tar---80

Solid material---room temperature

3. Product sludge fuel index

(1) Appearance --- gray black fuel slurry, with good fluidity, can be pumped

(2) Water content (weight%)---51.8

(3) Calorific value (received basis, kcal/kg)---3536

(4) Average particle size of solid particles in fuel (microns) --- 3.5

(5) Sulfur content (received basis, weight %)---1.08

(6) Ash content (received basis, weight %)---10.4

(7) Sulfur trioxide in ash (weight%)---14.08

Sulfur fixed in ash accounts for the proportion of sulfur in fuel (%)---54.2

Example 5

1. Raw material

Industrial sludge---same as embodiment 3

Powdered lignite produced in an open-pit coal mine

Granularity (mm)---2～4

Ash (weight%)---16.9

Calorific value (kcal kg)---3062

180# heavy oil---same as embodiment 1

lime mortar

Calcium content (dry basis%): >90

Water content (weight%): 70

2. Preparation conditions

(1) Raw material ratio (parts by weight)

Sludge---40

Lignite---40

180# heavy oil---20

Lime slurry (gram atomic ratio, calcium: sulfur) --- 6:1

(2) method

Mixed grinding method---first mix and grind lignite and heavy oil, then mix and grind the mixture with sludge and lime slurry to form fuel slurry, and grind the fuel slurry once more.

Material temperature (Celsius)

Heavy oil: 50℃ Other solid materials: room temperature

3. Product sludge fuel index

(1) Appearance --- gray black fuel slurry, with certain fluidity, can be pumped

(2) Average particle size of solid particles in fuel (micron)---6.7

(3) Moisture content (weight%)---44.8

(4) Calorific value (received basis, kcal/kg)---3589

(5) Ash content (received basis, weight %)---23.8

(6) Sulfur content (received basis, weight %)---0.64

(7) Sulfur trioxide in ash (weight %)---6.53

The proportion of sulfur fixed in the ash to the sulfur in the fuel --- 97.1.

Example 6

1. Raw material

Sludge from a paper mill in Shanghai---same as Example 2

Certain coal mine pulverized coal---with embodiment 1

Waste oil recovered from waste emulsion by a company in Shanghai (mainly light diesel)

Density (kg/L, 15°C)---0.9226

Water content (weight%)---0.82

Calorific value (kcal/kg)---8650

Heavy calcium carbonate---with embodiment 4.

2. Preparation conditions

(1) Raw material ratio (parts by weight)

Papermaking sludge---50

Pulverized coal---15

Emulsion waste oil---35

Heavy calcium carbonate (gram atomic ratio calcium: sulfur) --- 3:1

(2) Mixed grinding conditions --- Grinding step by step, first mixing and grinding sludge and waste oil, then grinding the mixture with coal powder and limestone into fuel slurry, and grinding the fuel slurry twice.

(3) Material temperature (Celsius)

Waste oil---50℃ Solid material---room temperature

3. Product sludge fuel index

(1) Appearance --- gray black slurry, with certain fluidity, can be pumped

(2) Moisture (weight%)---30.5

(3) Average particle size of solids in fuel (microns) --- 2.7

(4) Calorific value (received basis, kcal/kg)---4323

(5) Sulfur content (received basis, weight %)---0.37

(6) Ash content (received basis, weight %)---20.5

(7) Sulfur trioxide in ash (weight %)---3.25

The ratio of sulfur fixed in ash to fuel sulfur (%)---72.0

All documents mentioned in this application are incorporated by reference in this application as if each were individually incorporated by reference. In addition, it should be understood that after reading the above teaching content of the present invention, those skilled in the art can make various changes or modifications to the present invention, and these equivalent forms also fall within the scope defined by the appended claims of the present application.

Claims (13)

1. A sludge fuel, characterized in that it consists of the following components: (a) the aqueous sludge of 30-80 parts by weight; (b) 0.001-50 parts by weight of pulverized coal; (c) fuel oil of 10-70 parts by weight; Wherein, the average particle size of the solid particles is below 20 microns. 2. The sludge fuel according to claim 1, characterized in that, the average particle diameter of the solid particles is 0.1-20 microns. 3. The sludge fuel according to claim 1, characterized in that, the average particle diameter of the solid particles is 0.5-10 microns. 4. The sludge fuel according to claim 1, characterized in that the water content of the water-containing sludge is 30-90wt%. 5. The sludge fuel according to claim 1, characterized in that, the dry basis calorific value of the water-containing sludge is 2000 kcal/kg to 3500 kcal/kg. 6. sludge fuel as claimed in claim 1, is characterized in that, described hydrous sludge is selected from the following group: the domestic sludge that urban domestic sewage treatment plant produces, the paper mill sludge that paper mill wastewater treatment produces, Oily sludge, or mixtures thereof. 7. The sludge fuel according to claim 1, wherein the pulverized coal is selected from the group consisting of coke, coke chips, washed coal and washed leftover coal, or a mixture thereof. 8. sludge fuel as claimed in claim 1 is characterized in that, described fuel oil is selected from lower group: diesel oil, heavy diesel oil, heavy oil, residual oil, viscous crude oil, shale oil, petroleum coke, petroleum asphalt, Coal tar, waste fuel oil, waste cooking oil, waste industrial oil, pyrolysis oil of polymer substances or their mixtures. 9. sludge fuel as claimed in claim 1, is characterized in that, also contains desulfurizer, and the consumption of described desulfurizer is to make the gram atom ratio of calcium or magnesium in desulfurizer and the sulfur in fuel be at 1.0: Between 1～6:1. 10. The sludge fuel according to claim 1, characterized in that, said hydrous sludge is industrial sludge produced by sewage treatment of industrial enterprises. 11. The sludge fuel according to claim 1, characterized in that, said pulverized coal is selected from the group consisting of lignite, bituminous coal and anthracite, or a mixture thereof. 12. The sludge fuel according to claim 1, wherein said fuel oil is petroleum crude oil. 13. A method for preparing sludge fuel, characterized in that the method comprises the following steps: (i) mixing (a) 30-80 parts by weight of water-containing sludge, (b) 0.001-50 parts by weight of coal powder, and (c) fuel oil of 10-70 parts by weight to form a raw material mixture, (ii) Grinding the raw material mixture so that the average particle diameter of the solid particles in the fuel is less than 20 microns, thereby obtaining slurry-like sludge fuel; Or the method includes the steps: (a) 30-80 parts by weight of water-containing sludge (b) 0.001-50 parts by weight of pulverized coal and (c) 10-70 parts by weight of fuel oil are simultaneously fed into grinding equipment for grinding, so that the fuel The average particle size of the solid particles is less than 20 microns, so as to obtain slurry-like sludge fuel.