JPH0757874B2 - Method for producing solid fuel using wastes - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a solid fuel using wastes for producing solid fuels using domestic wastes and similar industrial wastes.

[0002]

2. Description of the Related Art Wastes such as household wastes and similar industrial wastes are increasing more and more, and a great deal of labor and cost are spent for their disposal. In recent years, these wastes are effectively recycled as resources. It is intended to be used.

As one of the effective methods, it is possible to use wastes as heat energy. Use of wastes as heat energy includes hot water conversion of incineration heat, steam conversion, electric conversion, gasification by thermal decomposition, and use after making oil, but the wastes are used as solid fuels. It is also considered to do.

The conversion of such wastes into solid fuel has the following advantages. It can be used in places other than garbage incinerators and has excellent versatility. The treatment equipment is cheaper than oil and liquefaction. Easy product transportation. Higher energy utilization rate than oil and liquefaction. The volume of garbage can be reduced significantly. Being quantitatively stable and being able to supply permanently.

[0005]

On the other hand, the following conditions (1) to (4) are required to have marketability as a solid fuel.

No harmful substances. Low ash content. Easy to handle and use. A large amount of heat is generated. Be cheap. Excellent storability.

Although attempts have been made to some extent in recent years to convert wastes into solid fuels, conventional solid fuels using wastes are sufficient, for example, they easily swell upon storage and generate odors and generate many harmful gases. Was not happy with.

An object of the present invention is to provide a method for producing a solid fuel using wastes capable of producing good quality solid fuels from wastes such as household waste and industrial wastes similar thereto. .

[0009]

SUMMARY OF THE INVENTION The present invention is a rough sorting step for sorting and removing heavy substances by using a sorting water tank for storing water such as household waste and similar industrial waste.
A crushing step of crushing the raw materials of the wastes remaining in this rough sorting step, a heavy tank is selected and removed from the raw materials of the wastes crushed by the crushing step using a water tank that stores water and has a stirrer In addition to washing and sorting the raw material, the raw material washed in the washing and sorting step is stirred by using a precise sorting water tank that stores water and is equipped with a stirrer to separate the heavy material from the raw material and to separate the heavy material from the raw material. A fine sorting step of sorting and removing, a dehydration and drying step of dehydrating and drying the raw material obtained in this fine sorting step, and a melting and forming step of melting the raw material obtained in the dehydrating and drying step and shaping it into solid fuel And a method for producing a solid fuel using wastes in which the water used is alkaline water.

[0010]

[Operation] Since alkaline water is used in each process, it can be processed without producing harmful gas and odor, and the obtained solid fuel is inexpensive and does not swell. As a result, the solid fuel can be produced efficiently.

[0011]

EXAMPLE The wastes used in the method for producing a solid fuel using the wastes of the present invention (hereinafter referred to as the production method of the present invention) include:
This includes household waste, plastic waste in household waste, so-called oversized waste, and similar industrial waste. Further, the wastes carried in are first crushed into bags and crushed, and then metals such as iron are recovered by magnetic transport, and in the past, wastes to be incinerated or landfilled are substantially used as raw materials for solid fuel.

In order to be a good quality solid fuel, it is indispensable that there is no harmfulness such as environmental pollution, and when waste materials are used as the raw materials, the harmful materials are mainly produced by the mixture of vinyl chloride products. Hydrogen chloride (Hcl). Therefore, in order to use it as a solid fuel, its removal and detoxification are essential conditions.

Therefore, in the production method of the present invention, firstly, the main purpose is to select and remove vinyl chloride products, secondly there is little ash content, and thirdly there is obtained a solid fuel which is easy to handle and use. The process is configured with the intention.

The manufacturing method of the present invention includes the following steps, and each step will be described below. 1st step Rough sorting step 2nd step Grinding step 3rd step Cleaning sorting step 4th step Fine sorting step 5th step Dehydration step 6th step Drying step 7th step Melting and molding step

About the First Step (Rough Sorting Step) The rough sorting step is carried out by a wet sorting method, and a wet sorting apparatus 1 for that purpose has a sorting water tank 11 and a central portion of the sorting water tank 11 as shown in FIG. Stirrer 12 provided near the water surface
A recovery conveyor 13 for recovering sediment, a recovery facility 14 for recovering fine sediment, and a recovery conveyor 15 for recovering floating material floating near the water surface.

The sorting water tank 11 is a long rectangular parallelepiped-shaped tank body that forms a water flow in one direction from the upstream end I to the downstream end O, and has a bottom portion at the deepest side in the longitudinal direction in this example. A groove portion 11A forming a part is formed. Further, a certain amount of wastes is continuously charged from a charging unit 11B such as a hopper provided at the upstream end I, and alkaline water is stored inside.

Further, the wastes, that is, the raw materials, which are supplied from the input portion 11B and enter the water tank, are sprayed with strong alkaline water which is, for example, 0.4% dissolved water of caustic soda and has a pH (PH) of 12.5. It

By using the alkaline water, the raw material can be made hydrophilic, the generation of static electricity can be prevented, washing, deodorization and reaction neutralization of hydrogen chloride can be carried out.

The caustic soda is used as the alkaline agent because it is easily soluble in water, the concentration can be easily adjusted, the cost is low, and the ash content is small. However, other agents can be used.

The wastes thrown into the sorting water tank 11 are
Heavy substances having a specific gravity of 1.0 or more, including metals, glass, earth and sand, heavy plastics such as vinyl chloride products, which are agitated by the agitator 12 in a water stream and are mixed in the raw materials, are sequentially settled during agitation and flow. .

As the agitator 12, a known one such as a mechanical type, a water sprinkling type and an aerator can be used.

The recovery conveyor 13 is, for example, a net conveyor, and successively carries out the settled heavy substances from the upstream end I to the outside of the tank.

The fine heavy substances passing through the mesh of the recovery conveyor 13 are collected in the groove 11A of the tank and recovered by the recovery facility 14 such as a screen recovery machine and a pump.

The heavy substance in this step is generally 8 to 10% by volume of the total volume, although it depends on the content of the raw material to be treated, and the separated heavy substance further contains residual valuable substances such as metals such as aluminum. After collection, it will be landfilled.

On the other hand, the wastes, which are light materials that are washed by the agitation and float, are provided at the downstream end O.
For example, it is scooped up by the recovery conveyor 15 which is a net conveyor and moves to the next crushing step.

About the second step (crushing step) The wastes which are the raw material are crushed by the crushing device 2 in a particle size of 15M / M mesh under, preferably 8M / M mesh under, and having no entanglement. Be crushed. As a result, waste materials that are a mixture of various materials,
That is, it is a pretreatment for homogenizing the raw materials, and further selecting vinyl chloride products that have been freed from the selection in the rough selection step, and further selected contaminants that generate ash.

As the crushing device 2, various types of crushers such as a shear type and a screw type can be used, but a screen type crusher is used because of clogging of the screen due to a large amount of water content, abrasion of the cutting curb, spillage of the blade and the like. Can be preferably used.

The crushed wastes are sent to the next washing and sorting apparatus step.

About the third step (cleaning and selecting step) The cleaning and selecting step is performed for the following purposes. To improve the dispersibility in water by washing the raw materials. To settle and sort vinyl chloride products and sludge. Use homogeneous materials by improving dispersibility.

In this example, the cleaning / sorting step is performed by the washing / sorting device 3 including the first tank 31, the second tank 32, and the terminal tank 33 in which the water flows in sequence.

The first layer 31 is provided with a stirrer 31A for storing strong alkaline water and vigorously stirring and washing the crushed raw materials that are sequentially received. As the stirring device 31A, a device having a rotor body, a vibrator,
Various things such as water flow and bubble generator can be used.

By washing with this strong alkaline water, oils and fats, sludge, etc. adhering to the wastes are washed off, and at the same time water repellency due to static electricity is also prevented and the dispersibility in water is improved.

The second tank 32 and the terminal tank 33 have settling assisting walls a ... Which meander the water flow up and down to settle heavy substances, and have a shower between the second tank 32 and the terminal tank 33. Alternatively, a vinyl chloride product which is not separated in the previous step by arranging a separating device 34 consisting of mechanical means to lightly impact the floating layer by the separating device 34 to promote dispersion,
Separates sludge and fine metals.

The raw material contained in the floating layer is stably supplied from the terminal tank 33 to the next fine sorting step using the pump P, and the outflow water accompanying the feeding is replenished in the first tank 31.

The heavy substances settled in this step are taken out by a recovery device (not shown) at the bottom when the water is stationary,
The heavy substances in this step are approximately 5 to 10% by volume of the input raw material.

About the fourth step (fine sorting step) The fine sorting step is performed in the fine sorting facility 4 and the specific gravity is 1.05 to 1.
72 vinyl chloride products and other contaminants are further removed.

The fine sorting apparatus 4 has a long, fine sorting water tank 41 in which water flows in one direction from the upstream end I to the downstream end O, and a settling assisting wall that gives a rapid flow and stagnation to the water flow assuming a river flow. The plates b are provided, and the floating means flowing on the upper surface is dispersed by a separating device 42 such as a mechanical means and a shower formed over the entire length to separate heavy substances.

As a result, in the fine sorting step, while the raw material transported by the pump P from the preceding washing and sorting step flows to the downstream end O, the heavy substances mixed by the inversion in the rapid flow and the stagnation are separated and settled. , Becomes a good quality raw material and is supplied from the downstream end O to the next dehydration step.

Similar to the washing / sorting step, the settled heavy material is collected when the apparatus is stopped and still water is used, but it may be continuously collected by a conveyor, a pump or the like.
The heavy substances settled in this step usually account for approximately 3 to 5% by volume of the received amount.

About the fifth step (dehydration step) The wastes from the precise selection step are dehydrated by the dehydrator 5. The dewatering device 5 includes a dewatering conveyor 51 that removes wastes from the fine sorting process during transfer, and a dewatering machine 52 that dewaters the dewatering conveyor 51, and dewaters the water content to about 40 to 50%.

As the dehydrator 52, a screen press, a roll press or the like capable of continuous treatment can be adopted.

About the sixth step (drying step) The raw material dehydrated in the dehydrating step is supplied to the dryer 6 in a fixed amount and dried to a water content of about 20%. In addition, dryer 6
For example, a kneading type can be used.

[0043] Incidentally, the raw material at this stage, the general of the incineration ^furnace
As a result of measuring hydrogen chloride concentration by burning at 4.26
.About.8.52 (mg / m @ 3 N), or 2.6 PPM.about.5.
It was 2 PPM. It can be seen that there is very little concern about pollution. Note that this production amount is considered to be due to the fact that a laminated film such as furniture plywood is left in the final peeling and mixed with the wood buoyancy into the selected raw material, but due to the improvement in the capacity of each step, the production amount is increased as necessary. It can be further reduced.

About the seventh step (melting and molding step) In the melting, the raw materials are kneaded at a high temperature with the following intentions. If vinyl chloride products remain in the raw material, pyrolyze them to render them harmless. Stabilize the flammability of the product as a homogenous melt. Be non-hygroscopic.

Further, in this embodiment, this step is performed by continuously melting and molding by using one integrated melting and molding apparatus 7. It can also be a separate body.

In this example, the melting and molding apparatus 7 comprises a screw shaft 72 linked to a variable speed drive unit 71 and a cylindrical case 73 in which the screw shaft 72 is housed. A raw material inlet 73A is provided at the base of the case 73. A carbon black quantitative addition device 73B is disposed on the downstream side.

Further, the inner peripheral surface of the case 73 is formed in a corrugated shape with irregularities, and a plurality of stop plates 73C for preventing the smooth transportation of the raw material are attached to the discontinuities of the screw blades. Will be distributed to.

In addition, a cooler 75 is provided in the molded portion 70B instead of the heater 74, and the stop plate 73D is easily attached and detached.

The raw material is continuously supplied in a fixed amount to the charging port 73A, and then the oily carbon black is added to and mixed with the raw material being stirred and transferred from the fixed amount addition device 73B.

The raw materials are repeatedly kneaded due to the resistance due to the unevenness of the inner peripheral surface of the case 73 during the transfer, the smooth transportation being hindered by the stopper plate 73C, and the temporary retention state often occurring, whereby the kneading is repeated. The raw material is heated to 300 ° C. to 350 ° C. by the heat and the adjustment of the heat of the heater 74.
As a result, the thermoplastic material in the raw material is melted into a black mud, and the non-melted material is adhesively included to form an integrated melted material.

Thus, as a result of melting at high temperature and vigorous kneading, the vinyl chloride product which begins to decompose at 140 to 150 ° C. is completely pyrolyzed.

In the melting step, the screw shaft 72 is preferably used depending on the mixing ratio of vinyl chloride products in the raw material.
Adjust the rotation speed of. When the mixing ratio is high, the rotation is slowed down and the retention at high temperature is lengthened to ensure the thermal decomposition. At that time, the treatment capacity is reduced, and therefore, the smaller the mixing ratio is, the higher the treatment capacity is. Therefore, the preceding removal of the vinyl chloride product is desired.

The alkali remaining in the raw materials impregnates the chemical decomposition with the thermal decomposition and the production of hydrogen chloride, immediately neutralizes the produced hydrogen chloride, and eliminates the odor generated by melting. Has an odor effect. Therefore, the odor in this melting process is very small.

The black carbon added to the raw material is an extremely small amount and makes the total amount pure black to enhance the commercial value of the solid fuel, and it is also useful for adjusting the blending ratio of other fuels such as wood waste fuel.

Further, in addition to carbon black, other combustible substances such as wood flour (oak tree), bark (bark), and paper pulp are added for the purpose of stabilizing the combustibility, adjusting calories, and utilizing waste materials. You can do it.

The melt moves to the forming portion 70B, is rapidly cooled by the cooler 75, and is formed into a solid fuel such as a pure black beautiful coal lump, chip shape, and powder by the residual heat cooling.

The cooler 75 is a fountain for spraying water,
An air blower for blowing air, or both may be used together.

When the solid fuel is powder, its particle size is
It is possible to increase / decrease the number of attachments of the stop plates 73D which can be easily attached and detached, and to select using a dusting machine if necessary.

The solid fuel thus obtained has the following features. (A) Harmless. (A) Low ash content. (C) It is non-hygroscopic and does not swell even when stored in open air. (D) A shape that is easy to use can be selected. (E) High calorific value. (F) A beautiful product with a pure black luster. (G) It can be provided at low cost.

Table 1 shows the results of component analysis of this solid fuel.

[0061]

[Table 1]

Table 2 shows the analysis results of the cinder of this solid fuel.
Is illustrated in.

[0063]

[Table 2]

Further, Table 3 shows the result of comparison of the weight percentage of ash content with that of coal and the like.

[0065]

[Table 3]

Table 4 shows the results of comparing the calorific value with that of coal.

[0067]

[Table 4]

In the manufacturing method of the present invention, water is used between the first step of rough screening step, the third step of washing and screening step, the fourth step of fine screening step, and the fifth step of dehydration step. The cycle is used, and this cycle will be described with reference to FIG.

In FIG. 2, the solid line shows the flow of water during work, and the broken line shows the flow when work is stopped. The numerical value shown as PH indicates the displayed water page.

As described above, the strongly alkaline water having a pH of 12.5 is supplied from the pH adjusting tank 100 to the sorting water tank 11 of the rough sorting facility 1, and the P
The water reduced to H8 is stored in the sewage water storage tank 102 through the floating sedimentation filtration tank 101. After being sequentially taken out and purified in the septic tank 103, they are stored in the purified water storage tank 104.

The purified water storage tank 104 is replenished with the reduced amount of water from the water source 105, and the water for pH 8 is supplied to the pH adjusting tank 100.

The pH adjusting tank 100 is supplied with an alkaline liquid such as caustic soda from the alkaline liquid tank 106, and the water is adjusted to, for example, PH12.5.

The water from the pH adjusting tank 100 is also supplied to the cleaning / sorting equipment 3 including the first tank 31, the second tank 32, and the terminal tank 33 in the cleaning / sorting step.

Further, this water is PH1 in the washing and selecting step.
When it decreases to 0.5, it is supplied to the precise selection water tank 41 of the precise selection equipment 4 in the precise selection step. By this process,
For example, when the water is lowered to PH10, the water removed by the water removal conveyor 51 and the dehydrator 52 in the dehydration process is sent to the floating sedimentation filtration tank 101 and reused.

The PH value shown in each step is an example.

When the work is stopped, the water in the purified water storage tank 104 is directly sent to the sorting water tank 11 and the washing / sorting equipment 3, and the water for the washing / sorting equipment 3 is fed from the precise sorting equipment 4. A small amount of water circulates without going through the dehydration equipment 5.

[0077]

As described above, according to the method of the present invention, since alkaline water is used in each step, it can be processed without producing harmful gas and odor, and the obtained solid fuel is inexpensive and does not swell. In addition to the improvement, the processing equipment cost can be significantly reduced compared to the incineration equipment, and the automatic operation,
It is also possible to reduce power consumption.

[Brief description of drawings]

FIG. 1 is a diagram illustrating a facility used in the method of the present invention.

FIG. 2 is a diagram illustrating the flow of water.

[Explanation of symbols]

 1 Wet sorting device 2 Grinding sorting device 3 Washing sorting device 4 Precision sorting device 5 Dehydration device 6 Drying device 7 Melting and molding device 11 Sorting water tank 12 Stirrer 13 Recovery conveyor 14 Recovery facility 15 Recovery conveyor 31 First tank 32 Second tank 33 Third tank 31A Stirrer 34 Separation device 41 Fine selection water tank 42 Separation device 72 Screw shaft 73 Case 73B Carbon black quantitative addition device

Claims (6)

[Claims] 1. A rough sorting process for sorting and removing heavy substances by using a sorting water tank that stores water for waste such as household waste and similar industrial waste, and wastes remaining in this rough sorting process. A crushing step of crushing the raw material, a washing and sorting step of washing and removing the heavy material from the raw material of the wastes crushed by the crushing step using a water tank that stores water and is equipped with a stirrer, and washing the raw material, A fine sorting step of agitating the raw material washed in the washing and sorting step using a fine sorting water tank that stores water and is provided with a stirrer to separate heavy substances from the raw materials and to sort and remove the heavy substances It consists of a dehydration and drying step of dehydrating and drying the raw material obtained in another step, and a melting and forming step of melting the raw material obtained in the dehydration and drying step and shaping it into a solid fuel, and the water for use is alkaline. Method for producing a solid fuel using a the wastes. 2. In the rough sorting step, the sorting water tank comprises a long rectangular parallelepiped tank body forming a water flow in one direction from an upstream end to a downstream end, and the sorting water tank has a central portion. And a stirrer provided near the water surface, a recovery conveyor for recovering sediment, a recovery facility for recovering fine sediment,
The method for producing solid fuel using wastes according to claim 1, further comprising a recovery conveyer for recovering floating substances floating near the water surface. 3. The method for producing a solid fuel using wastes according to claim 1, wherein in the crushing step, the wastes are crushed into a shape having no entanglement with a crusher. 4. The washing and sorting step uses a first tank provided with a stirring device through which water flows in sequence, a second tank 32 having a sedimentation-promoting wall that meanders a water stream vertically to settle heavy substances, and a terminal tank. The method for producing a solid fuel using wastes according to claim 1, wherein the solid fuel is washed and sorted. 5. In the melting and molding step, the raw material is heated to 300 ° C.
The method for producing a solid fuel using wastes according to claim 1, wherein the temperature is raised to 350 ° C. 6. The method for producing a solid fuel using wastes according to claim 1, wherein the melting and molding steps include an addition step of adding carbon black to the raw material.