GB2175601A - Composite fuel & colloid mill for production thereof - Google Patents

Abstract

A composite fuel is disclosed, which comprises a carbonized substance such as carbonised plants, subjected to super colloidal milling continuously to achieve a particle size of less than 30 microns, oil and water. The resulting fuel is a stabilized colloid. A process and apparatus for manufacturing the fuel are also disclosed. The apparatus may comprise two super colloid mills arranged in sequence, each being as shown, the clearance of the girders D-5, D-6 in the first mill being adjusted within a range of 0.4-0.7 mm, and in the second within a range of 0.01-0.03 mm. <IMAGE>

Description

SPECIFICATION Composite fuel The present invention relates to a composite colloidal fuel comprising carbonized substances of plants, oils and water, and to a process and apparatus for manufacturing the fuel.

Carbonized substances of plants are inconvenient as regards handling such as transport and storage, etc compared with liquid fuels because of their solid form. Atechnique to convert these carbonized substances into liquid fuel is therefore desirable and much research has been conducted to develop a suitable technique.

Conventional processes for manufacturing composite colloidal fuels comprising carbonized substances, oils and water (hereinafter abbreviated as CCOM) are classified generally, as shown in Figure 1, into processes according to system Awherein CCOM is manufactured after pulverizing the carbonized substances of plants in a dry process and that of system B wherein CCOM is manufactured after pulverizing the carbonized substances of plants in a wet process. Both of these systems require a process step for pulverizing the carbonized substances of plants and a process step for mixing with oils and bringing to colloidal form.

Forthis reason, the manufacture is both time-consuming and expensive.

When using a screen mill (hammer mill), roll mill, vibratory ball mill, mortar, etc. employed currently for coarse or fine pulverization of carbonized substances of plants, two or three process steps are necessary for the manufacture of CCOM. Moreover, the particle size of carbonized substances of plants is never less than 100 microns in these cases.

As a result of various investigations the present inventors have found that the carbonized substances of plants can be pulverized to particles of less than 20 microns in a super colloid mill (such as the mill manufactured under the trade name: Masscolloider) and, at the same time, CCOM can be manufactured by an improved process wherein oil and water are mixed well with carbonized substances of plants and brought to colloidal form.

For improved results using a super colloid mill, the present inventors found that the clearance could be adjusted below 0.01 mm by making two upper and lower grinders which form the heart of the Masscolloider composite, and vitrified grinders (whetstones) made composite by the impregnation and polymerization of polymers to renew entirely the quality of the material. These vitrified grinders having been made composite with a polymer (for example those manufactured underthe trade name: Grindel) were fitted to a Masscolloider and tests were carried out over a long period of time. In consequence, it was confirmed that carbonized substances of plants could be pulverized to less than 20 microns without any damage.When, oils were added further in equal amounts and to the resulting slurry was added less than 20% of water together with small amounts of dispersing and stabilizing agents introduced to the super colloid mill. When the grinder was allowed to rotate at 1,450 rpm under the predetermined conditions squeezing the clearance as narrow as 0.01 mm, stable CCOM was ejected continuously from the outlet. Repeated experiments demonstrated that carbonized substances of plants can be pulverized while the three materials viz:carbonized substances, oils and predetermined amounts of water added were converted finally to give CCOM continuously in an extremely stable form through the action of dispersing and stabilizing agent.

Furthermore, secondary aggregation was prevented by passing through a line mixer, and CCOM having an enhanced stability over a long period of time can be manufactured.

From the trial calculation of the running costs for the manufacture compared with that of conventional processes, it became clear that the costs was about 400 yen/ton according to the process of the present invention which corresponded to about one third to one fourth of that according to conventional processes.

The fact that CCOM can be manufactured continuously in a single process step as in the present invention contributes greatly to the improvement in the productivity.

CCOM is a Bingham fluid (non-Newtonian property) having a yield value and the apparent viscosity thereof depends on the rate of deformation or the shear force. It exhibits the thixotropy which is seen frequently among fluids of dispersed systems and it has time-dependency. Therefore, a lot of factors can influence the manufacture of CCOM having both fluidity and stability.

Enumerating these factors, there are (1) physical properties of carbonized substances of plants, (2) type, addition amount and state of addition of dispersing and stabilizing agent, (3) rate of water in CCOM, in other words, composition ratio by weight of the components constituting CCOM, (4) equipment for the manufacture, (5) process for its manufacture.

(1) The carbonized substances of plants are porous and can adsorb moisture, being different from the coal.

Moreover, although the values of basic physical properties of coal vary depending on the producing districts, those of carbonized substances obtained by the carbonization of plant bodies are not significantly influenced by the types of plant bodies, the conditions of carbonization, etc. The content of impurities, for example, sulfur is low and the organic matters are hardly contained in the carbonized substances. Pure carbon content lies between 45% and 55%.

This means that the carbonized substances are not only very clean but also easy to pulverize when used as a fuel. Moreover, as to the particle size and the particle size distribution,when manufacturing CCOM by using a Masscolloider equipped with Grindel, the particle size distribution concentrates to 20 to 5 microns, depending on the adjustment of the clearance. It has also been recognized that the shape of flame is good at the time of combustion because of the uniformity of the diameter of particles and that the choking of nozzles of burner does not occur.

(2) As to the dispersing and stabilizing agents, all ofthose on the market and currently used for CCOM are suitable. Since CCOM contains water within a range of 10 to 20%, the freedom of the selection of dispersing and stabilizing agent is broad.

The addition rate is preferably less than 0.1% in terms of pure matter based on the total weight of CCOM and the method for addition is preferable to stir well with homogenizer after added required amounts of aqueous solution of dispersing and stabilizing agentto oil beforehand.

CCOM comprises four components, that is, carbonized substance of plant, oil, water and very small amounts of dispersing and stabilizing agent, and both the quantity of heat and the viscosity vary with the weight ratio of the composition.

Water adsorbed is present in small voids of porous carbonized substance, oil is filled up in large pores and dispersing agent lies at the interface of carbonized substance and oil. One of the features of CCOM is that 10 to 20% by weight of water is present in CCOM. The presence of water makes possible the manufacture in a single process step.

The ratio, carbonized substance: oil is preferable to be within a range of 50:50 to 35:65 and 10 to 20% of water become necessary based on the weight of these carbonized substance and oil.

(3) As to the equipment for the manufacture, it is a special feature that the super colloidally milling portion ofthe Masscolloider is made composite with a polymer, and the mixed slurry comprising coarsely pulverized carbonized substance of plants, oil, water and very small amounts of dispersing and stabilizing agent is fed continuously into the inlet. When the slurry passes through the super colloidally milling portion adjusted to the predetermined clearance, the coarsely pulverized carbonized substance is subjected to fine pulverization, while a homogeneous colloid is formed under the influence of dispersing and stabilizing agent, and CCOM flows out from the ejection outlet. When a high viscosity slurry is fed, heating up to 800C is possible since the outside of the super colloidally milling portion is enclosed by a warming jacket.

For manufacture, the clearance at the super colloidally milling portion is adjusted to the predetermined condition to control the particle size and the production rate.

Based on the facts described above, the stabilization mechanism at the time of the manufacture of CCOM using manufacturing process and equipment of the invention is inferred as follows: namely, the carbonized substance which is porous has a wide surface area and the exposed surface is almost covered with polar -OH groups. If existing water molecules are present, water adheres to -OH groups preferentially. When high molecular substance and surfactant with hydrophilic groups intrude into such a system, the surface tension is lowered and water covers the carbonized substance. At this time, the adsorbed state of the ionic surfactant is considered as follows: the functional group portions of the carbonized substance adsorb the side of hydrophilic groups and the hydrophobic groups are compelled to orient to the side of water.However, this is unstable thermodynamically, so that bimolecular adsorption is realized. Moreover, the hydrophobic groups adsorb on the surface of the carbonized substance.

On the other hand, at the interface of water and oil, the surfactants act by orientating the hydrophilic groups thereof to the side of water and the hydrophobic groups thereof to the side of oil. Through the existence of ionic surfactants and water on the surface of the carbonized substance, the surface of the carbonized substance becomes electrically charged. As described, when approaching each other, the particles of carbonized substance become stable thermodynamically through the reduction of the interfaces with water and oil And when balance is achieved between the electrostatic repulsive force and the van der Waals force, the particles of carbonized substance are mutually protected and become stable.

When manufacturing CCOM by the use of the manufacturing process and the equipment according to the present invention, it became possible to produce CCOM which was stable over a long period of time with inexpensive running cost.

The invention is further illustrated with reference to the accompanying drawings wherein: Figure 1 is an illustrative diagram showing a conventional process for the manufacture of CCOM.

Figure2 is an illustrative diagram showing a process for manufacturing CCOM according to the present invention.

Figures 3(A) and(S) are a whole view and an illustrative diagram of section of the super colloid mill to be used in the invention.

Figure 4 is illustrative diagrams of the manufacturing equipment showing the example of the invention.

With reference to Figure 2, the carbonized substance of bark (moisture content: about 7%) having a particle size of less than 5 mesh (less than 3,962 > m) ejected from the impact pulverizer wherein the pulverization proceeds through the impact and shear action and the particle size is regulated on the screen by means of centrifugal force and force of the air stored in the tank.

In a test, 510 kg of A grade havy oil were transferred from the oil tank into the mixing tank, and 4.43 kg of dispersing and stabilizing agent and 126 keg of water were introduced through respective pipes into the mixing tank. In the mixing tank, the mixture was stirred at about 1000 to 1500 rpm to homogenize these three components and fed to the slurry bath via P. The stirrer in the slurry bath rotates at a speed of 200 to 500 rpm and, when 316 kg of the bark charcoal aforementioned were added gradually to this slurry bath, the mixture became a homogeneous slurry after several minutes. The homogenized slurry was fed to respective hopper D-1 of the first super colloid mill D1 and then of the finishing super colloid mill D2 (Masscolloider MKZA 10-10 with a built-in Grindel) by using line homomixer.This is further described with reference to Figure 3.

The clearance of Masscolloider D1 in the first super colloid mill is adjusted beforehand to 0.06 mm, D-2 is closed and D-3 is locked in the state of switch-off. Then, D-4 is turned and, taking a point wherein D-6 contacts with D-5 and D-4 becomes not to move as O-point, the clearance is inspected again.

When D (device) is switched on, D-6 rotates at 1450 rpm and the slurry converted to CCOM pours continuously from the ejection outlet. This is introduced again to Masscolloider D2 in the finishing super colloid mill. By allowing to pass continuously through D2, the clearance thereof having been adjusted to 0.03 mm, CCOM flows from the ejection outlet of D2 and is accumulated in the storage bath. It enters the storage tank of CCOM from the storage bath via line mixer.

The particle size of carbonized substance in CCOM obtained was as follows: Weight (%) 0 0 0 0 8.5 21.8 8.7 11.5 8.4 8.8 Particle size 60 50 40 30 20 10 8.0 6.0 5.0 4.0 ( > m) Weight (%) 10.3 10.1 9.1 2.8 - - 100 Particle size 3.0 2.0 1.0 0.8 0.6 0.5 ( > m) The quantity of heat was 7990 Kcal/kg which was a little higher than the calculated value of 7810 Kcal/kg.

The viscosity was 4,650 cp. The composition by weight of CCOM obtained was 45% carbonized substance, 55% A grade heavy oil and about 15% water, and the total volume was about 900 e. The latter was to be obtained in amounts of 924 e from the calculation. The apparent bulk specific gravity was 1.06.

The volume fraction of CCOM obtained was found to be: Vc (carbonized substance) = 0.19, Vo (oil) = 0.65, Vmo (water) = 0.16. The combustion test with spray burner showed excellent combustion.

Example Figure 4, illustrates one embodiment of manufacturing equipment for CCOM with a capacity of 400 kg/hr.

In Figure 4, the reference numerals have the following meaning: 1 Stirrer 2 First Masscolloider 3 Storage bath 4 Finishing (second) Masscolloider 5 Line mixer 6 Allocation storage bath P1 - P4 ,,.,,,,,,,,,,,,,,,,,, Sludge pump A specific example is illustrated below in detail using this equipment. The carbonized substance which had been extracted from a carbonization furnace burning waste woods left on the forest floor and pulverized coarsely using a simple device was screened to less than 5 mesh with a Supermicron pulverizer (at this time, moisture content was about 7%), transported via a pipe and fed to (1).

To 1.85 kg of Ribolac 400 (purity: 37.4%, made by Lion Oil and Fat Co.) and 0.95 kg of CMC, both being used as dispersing and stabilizing agents, were added 155 kg of water and 466 kg of A grade heavy oil. The weight ratio of the mixture of oil and water having been adjusted, the composition was transported from the mixing tankthrough pipe to introduce to (1) continuously.

The ratio of composition of carbonized substance to the mixture of oil, water and dispersing and stabilizing agent was adjusted as follows and the mixture was stirred in (1) to make homogeneous: [carbonized substance 45, oil 55; water 15%; dispersing and stabilizing agent 0.3%].

The slurry mixed with the stirrer in (1) was fed to the manufacturing equipment of the invention (2) with P1.

(2) is Masscolloider MKZB 15-50 with a built-in Grindel made composite with polymer. The slurry was milled super colloidally in Grindel which rotated at 1,450 rpm and the clearance of which was 0.8mm, while it was accumulated in storage bath (3) (600 e).

Further, being transported with P2 and P3, the slurry entered super colloid mill (4) (same as (2)), passed through Grindel which rotated at 1,450 rpm and the clearance of which was 0.02 mm, and entered Homomic line mill (5) with P4. In this line mixer (Homomic line mill), by opening the clearance dial to maximum and by adjusting the number of rotation to less than 1000 rpm, the secondary aggregation was prevented, and, in this state, the slurry entered the allocation storage bath (6) (1000 e).

The special feature of the invention is to pass through (2), (4) and (6), and the process for the manufacture includes (1) through (6).

The test results of the quality of slurry in the allocation bath were as follows: Carbonized substance 45 A grade heavy oil 55 Moisture 15.5% Viscosity 5900 cp Specific gravity 1.09 Heat vale 7620 Kcal/kg Production rate 400 kg/hr Volume fraction Vc = 0.22 Vo = 0.61 Vmo = 0.17 Besides, the determination of the particle size distribution of carbonized substance gave following result.

Weight (%) 0 0 0 0 9.7 23.8 7.5 9.5 7.5 8.4 Particle size 60 50 40 30 20 10 8.0 6.0 5.0 4.0 ( > m) Weight(%) 9.2 10.3 8.2 2.8 3.1 - 100 Particle size 3.0 2.0 1.0 0.8 0.6 0.5 (cm) On putting the invention into practice, it is desirable that the raw materials to be used for the invention lie within the following regulation ranges.

1. Carbonized substances ofplants Plants or solid extracts thereof such as wooden substances, agricultural wastes, for example, rice straw, peanut shells, nuts, cotton plant, further paper in the industrial wastes, etc. are used. The conditions for the carbonization do not have specific limits. Desirably the organic substances can vaporize at high temperatures and the fixed carbon is present in amounts of more than 40%.

2. Oils Kerosene, A and C grade heavy oil, waste oil and other oils for fuel can all be used as raw materials.

3. Dispersing and stabilizing agents All commercial dispersing and stabilizing agents for COM and CCOM used the surfactants as main raw materials can be used. However, Ribolan 400 (liquid), Ribolan 1400 (powdery), Teikopol (liquid), etc. are preferable because of their low price.

The stability can be increased by adding CMC (Carboxymethylcellulose), sodium polyacrylate or the like at a rate of 20 to 30% based on the weight of the above surfactants. The addition rate of dispersing agent is limited to 1% at most in terms of dry matter based on the total weight of CCOM.

4. Water Tap water may be used. Alcohols in an amount up to 10% based on the amount of water may be added.

The weight content of the water and alcohol has an upper limit to 20% based on the weight of CCOM.

5. Composition of CCOM Although a carbonized substance and oil are fundamental components of the present invention, fine powders of plants, petroleum coke, etc. can be added within a range of 3 to 5% based on the weight of carbonized substance: oil forthe purpose of the regulation (design) etc. of combustion characteristics such as centralization of flame, heat loss, exhaust gas and quantity of heat.

The pulverization of carbonized substances in a dry process has problems for the health of workers, is hazardous and furthermore, it is difficult to obtain the carbonized substances with fine particles considering that the running cost (consumption power) is expensive. For these reasons, the wet process is generally used.

According to the present invention, the equipment having been considered hitherto to be impossible to pulverize to less than 20 microns has been realized and besides the technique to make composite with oil has been found. The significant means for the solution of these lies in that the grinders for the super colloidal milling were made composite with polymer.

In the present invention, it has been found further that the pulverization of carbonized substances and the conversion to colloidal form can be performed simultaneously in a single process step as opposed to two to three processes in the conventional manufacturing process of colloidal fuel. Further, such features have been confirmed that the secondary aggregation is not caused as the physical property of CCOM obtained, that the nozzles are not choked at the time of combustion, that the injection opening of nozzles can be reduced, that the elongation and the spreading of flame are excellent, that the combustion efficiency is high, and the like.

Now, calculating on trial the cost required for the pulverization of carbonized substances of plant bodies by the use of Supermicron pulverizer employed most frequently for the pulverization in dry process from the consumption power as an example, it amounts to 2,592 yen/ton for a raw material with a moisture content of carbonized substance of 8.5% and 2,828 yen/ton for a carbonized substance in the an hydros state. Whereas, according to the invention, the cost calculated from the consumption power amounts to 400 yen/ton including the pulverization and the conversion to the colloidal form wholly.In the case of Supermicron pulverizer, the consumption power necessary for the mixing of oil with water and the conversion to the colloidal form costs a further 350 yen/ton.Therefore, the calculation from the consumption power for these shows that the running costs may be about one eighth in accordance with the present invention. In addition, there is a benefit that the particle size is very fine being less than 20 microns, and further, advantages arise from the reduction in labor costs and reduction in area of mill installation resulting in further economy.

Although natural plant bodies decay in several years if left in their natural state, it becomes possible to store them for thousands of years if they are carbonized. With current environmental and industrial problems instrumental systems are devised on the assumption of the use of electricity, gas and liquid fuel.

Therefore, the use of firewood and charcoal as fuel in their natural state can hardly be considered.

CCOM wherein apparent bulk specific gravity is made high and fluidity (colloidal form) convenient from the aspects of hanlding such as transport, storage, etc. is afforded has very large social benefits as a new fuel. Leaving the age when single fuels, for example, petroleum, coal or firewood are used, supply of the composite fuel having the quantity of heat required for the purpose of use is tied up directly with the saving of resources and the energy conservation, so that it gets to be a promising fuel in our country where the fossil resources are poor.

Moreover, since the carbonized substances of plants are clean, with the colloidal fuel made composite with oil, Sox per weight is reduced and the function of water in CCOM acts on the decrease in Nox. These facts may be advantageous for the anti-pollution measures in fuels used for boilers in the industrial area and at power stations.

Claims (6)

1. A composite fuel comprising a stabilized colloidal mixture of a carbonized substance having been subjected to continuous super colloidal milling to achieve a particle size of less than 30 microns, oil and water.

2. A composite fuel according to claim 1, wherein the composition weight ratio of carbonized substance to oil is within a range of 35:65 to 49:51.

3. A composite fuel according to claim 1 or 2, wherein water coexists in an amount of 20 to 10% by weight.

4. A composite fuel according to any of claims 1 to 3, wherein the heat value is within a range of 7,000 to 8,500 Kcal/kg.

5. A process for manufacturing a composite fuel wherein, in a single process a carbonized substance is submitted to super colloidal milling continuously to a particle size of less than 30 microns using a super colloid mill wherein the grinders are made composite with a polymer while oil and water are introduced into the mill to obtain a stabilized colloid.

6. An apparatus for manufacturing a stabilized composite by the process according to claim 5, comprising a super colloid mill wherein the clearance of the grinders is adjusted within a range of 0.4 to 0.7 mm, and a second super colloid mill wherein the clearance of Masscolloider is adjusted within a range of 0.01 to 0.03 mm arranged in sequence.