JPS5963189A - Preparation of stable coal-water slurry - Google Patents

Abstract

PURPOSE:To obtain a slurry having improved stability on standing, by blowing air into a coal-water slurry containing fine powder of coal, a dispersing agent and water in the presence of a specific microorganism. CONSTITUTION:A petroleum assimilable microorganism, e.g. Pseudomonas aeruginosa (ATCC No. 21036), which is a microorganism capable of growing vigorously by using a hydrocarbon, e.g. a petroleum compound, as a sole carbon nutrient source is used. Powder of coal is mixed with about 0.05-5wt%, based on the coal, dispersing agent, e.g. ammonium salt of beta-naphthalenesulfonic acid- formalin condensate, and water in a wet ball mill, and the resultant coal-water slurry containing about 30-85wt% coal is then fed to a tank, inoculated with the petroleum assimilable microorganism at about 20-50 deg.C, mixed and stirred for about 10hr or longer while blowing air thereinto.

Description

[Detailed description of the invention] Misfire F! A relates to a method for producing a coal/water slurry with good static stability. For more details, fine coal powder, water,
The present invention relates to a method for producing a coal-water slurry with good standing stability, which comprises blowing air into a coal-water slurry containing a dispersant in the presence of specific microorganisms.

In recent years, petroleum, which has been the most widely used energy source, has reached the limit of its reserves. Diversification of energy sources and securing stable supply have become important issues due to the soaring prices associated with t-ts. From such a thing,
The effective use of coal, which has large reserves and is not unevenly distributed around the world, is becoming increasingly important. However, unlike petroleum, coal is a solid substance, so it cannot be transported by pipeline, which is extremely disadvantageous in terms of handling. Furthermore, coal generally contains a large amount of ash compared to petroleum, and has problems such as a decrease in calorific value and the disposal of fly ash. For this reason, in order to improve the handling disadvantages, various methods have been studied in which coal is pulverized and dispersed in water to form a slurry. However, in this case as well, increasing the coal concentration will result in significant thickening and loss of fluidity, while decreasing the coal concentration will reduce transport efficiency and further increase the cost of the dewatering process. Not practical. This is because the coal particles in the coal/water slurry aggregate in water, causing an increase in viscosity and a decrease in fluidity. The smaller the coal particles in the water slurry, the better the dispersion stability, but the cost of pulverization increases as the degree of pulverization increases. Currently, the amount of pulverized coal being burned in thermal power plants is 200 mesh, 80% bus, t 'x b, or about 7
Since the particle size is about 4 microns, it is expected that this particle will be used as a guideline for the particle size of pulverized coal. When a surfactant, which is a dispersant, is added to the coal/water slurry, the surfactant is adsorbed to the interface between the coal particles and water, causing the coal particles to break apart or coagulate with each other. It is expected that this will have the effect of preventing this, creating a good dispersion state.

The present inventors have already developed various dispersants that have such effects (for example, Japanese Patent Application No. 54-95175).
issue). However, although such a dispersant improves fluidity, when left standing, the sediment is compacted to form a hard cake, so it is not necessarily satisfactory in practice.

On the other hand, in the natural world, especially in the microbial world, the existence of petroleum microorganisms that actively assimilate and multiply using water-insoluble petroleum compounds, especially linear hydrocarbons, as carbon source nutrients has been known for a long time.

In recent years, many studies have been conducted on how microorganisms utilize water-soluble petroleum compounds (Erj, c.
keo'n and Nakahara ;' Pr
oca day eBiochem'', 1975 (S) 9-13
．． and cooper and Zajl CA Adv, App.
l, Miorobiol, 26, 229-250 (
(1980)) was developed, and as one means of introducing petroleum compounds into microbial cells, microorganisms actively secrete emulsifying substances, that is, surfactant substances, into the extracellular culture medium E7, a water-insoluble petroleum compound. It has become clear that microorganisms are emulsified and taken up into microbial cells as micellar particles.

In addition, surfactants secreted by microorganisms have different structural characteristics than synthetic surfactants, and many of them cannot be adjusted using current synthetic techniques. Further, although detailed research has not yet been conducted on its surface chemical properties, it is expected to exhibit characteristic interfacial phenomena not found in synthetic surfactants.

Under these circumstances, the present inventors have conducted extensive research on the utilization of surfactant substances secreted by microorganisms for coal-water slurry, and as a result, they have arrived at Himi BAtrc. That is, the present inventors blew air into a coal/water slurry containing a specific petroleum-utilizing microorganism in the coexistence of a dispersant, so that the petroleum-utilizing microorganism could carbonize the coal in the coal/water slurry. It was found that it multiplies as a source. When the coal water slurry containing the skeleton microorganisms and the fermentation products of the microorganisms obtained through the proliferation of these oil-utilizing microorganisms is left for a long period of time, the sediment does not form a hard cake and is in a stable state. I discovered that it can be maintained [7 non-inventive activities have been achieved.

That is, the present invention involves blowing air into a coal/water slurry containing fine coal powder, water, and a dispersant in the presence of petroleum-utilizing microorganisms that grow in a growth medium with hydrocarbons as the sole carbon source. The present invention provides a method for producing a stable coal/water slurry characterized by:

The method of the present invention will be described in more detail below.

That is, in the presence of a dispersant, a water slurry of coal is prepared using a wet ball mill or the like, and then petroleum-assimilating microorganisms are inoculated into the slurry and mixed while blowing air in a pipe or a tank at 20 to 5 oc.

In this case, it is preferable to stir and mix using a stirrer or the like. Further, if the microorganisms specified in the present invention are present in the coal from the beginning, the inoculation operation may not be performed. The aeration time required to stabilize the slurry in such a process depends on the coal type,
Although the temperature conditions, concubine type, amount of ventilation, etc. vary, the period is generally 10 hours or more, preferably 24 hours or more.

1 to 3 show process diagrams of a specific example of the i-adic method of the present invention.

The petroleum-utilizing microorganism used in the present invention is a microorganism of the genus Pseudomonas (P.
seudomonae), Corynebacterium J3g
(Oorynebaoterium), Nocardia, Arthronocutel (
Arthrobaater), /Z Shirasu (B
acillus) and alkaline earth metals (Al'aal
microorganisms selected from the group consisting of P. igenes).

Examples of these microorganisms include Pseudomonas aeruginosa.
sa) ATOO deposit number (hereinafter abbreviated as ATOOA)
21036. cOr7nAbaO-terium-hy
drocarboC1a8t, um) ATOO4155
92, Norcadia rosea
a-paraffinica) ATC! OA2119
B, Arthrobacter no (Ruffineus (Ar1)
1;hrObjectgr-paraffineus)
Examples include ATOOA 15591.Although the dispersant used in the present invention may be any surfactant that can lower the viscosity of the coal-water slurry and increase its concentration, the following compounds are particularly preferred.

That is, at least one of the active ingredients is a formalin condensate of a sulfonated polycyclic aromatic compound which may have a hydrocarbon group as a substituent, or a salt thereof, such as an ammonium salt of a β-naphthalene sulfonic acid formalin condensate. A dispersant containing or an alkylene oxide that essentially contains ethylene oxide is added to a compound having active hydrogen, and the total weight of the polyoxyethylene chain portion is 40 to 95% by weight of the total molecular weight, and the molecular weight is 2, 0 mouth 0 ~ ioo, oo.

A dispersant containing a polyether compound or a derivative thereof as an active ingredient, such as a polyoxyethylene (EO) polyoxypropylene (PO) adduct of glycerin (molecular weight 1'o, o o o, po/po ratio = 4/
6) etc. The amount of dispersant added is 0.0 to the coal.
05-5-0 wt%, preferably 0.1-1.0 wt%
It is.

The coal used in the present invention may be of various types such as anthracite, bituminous coal, sub-bituminous coal, lignite, etc., and is used by finely pulverizing totofi. Furthermore, the production method of the present invention is effective even when these coals have undergone a coal cleaning process (deashing process) by flotation or the like. The particle size of this coal powder may be any particle size that allows direct combustion in the boiler, but the general particle size currently used in thermal power plants for this purpose is one with a 20D mesh pass rate of 70 to 90%. It is of granularity.

Coal/Water Slurry IJ <If the concentration of the constituent coal is too low, the transportation efficiency will be poor and the dewatering process will be costly, making it meaningless. In addition, if the viscosity is too large, the viscosity will be too high, so according to the method of the present invention, the viscosity is generally 30 to 85, preferably 5.
It is possible to obtain a coal/water slurry that is stably dispersed at a high concentration of 0 to 75% by weight, and has low viscosity and good fluidity.

In order to separate and recover coal from the slurry produced by the method of the present invention after its use as a transportation means, a third liquid, hydrocarbon, which is immiscible with water as a dispersion medium is added to the slurry. A method of granulating coal powder by adding oil, etc., and separating and recovering it from water is attracting attention (for example, Japanese Patent Laid-Open No. 52-37901). For this purpose, hydrocarbon oil may be added when preparing the coal/water slurry in advance. It shows excellent performance even in systems without losing its dispersion stabilizing effect.

EXAMPLES The present invention will be specifically explained below with reference to Examples, but the present invention is not limited to these Examples.

Example 1] (1) Slurry production method and fluidity evaluation Diameter 30 cr
200 magnetic balls with a diameter of 30 mm in a pot type ball mill
11.6 kg of Preasol charcoal, which was charged with 100 balls of 5 to 6 particles in diameter and 5 to 6 pounds of water.
4 to 9. After adding 108 fi of β-naphthalene sulfonic acid formalin condensate ammonium salt, the pot was rotated at a rotation speed of 200 rpm for 1 hour to perform pulverization.

Then, 10 kg of the produced slurry was transferred to a 120 t flask, and Peeud, omonas aorugi was grown on an ordinary agar medium (manufactured by Difco) for 3 DC for 2 days.
nosaATOC! 21036i was taken aseptically with a platinum loop, and the platinum loop was added to the slurry and air was added to the slurry.
00ml/min and left to stand for 24 hours while stirring.

Next, the viscosity was measured using a B-type viscometer to evaluate the fluidity. The results are shown in Table 1.

*1 Blair sole coal calorific value 6720 kt:al/ky (, T-work 8 M8
814) Ash content 7.1% (J Engineering S
M8812) Moisture 7.0% (51
5M8811) Fixed carbon 59.7% (J Engineering S M8812) (2) Evaluation of stability of water slurry The stability of the slurry was evaluated at 30 days and 60 days after producing the slurry.
After leaving it for a day, a stainless steel rod with a diameter of 5 mm (M amount 501
) was gently poured into the slurry and its sedimentation state was observed.

The results are shown in Table 1.

As is clear from Table 1, the slurry prepared in this example had good stability, and there was almost no compaction even after 0 days.

[Examples 2 to 11, Comparative Examples 1 to 5] In the same manner as in Example 1, the type of inoculum, the amount of air blowing, the time of air blowing, the type of dispersant, and the coal concentration were changed as shown in Table 1. A slurry was prepared and its stability was fully evaluated. The results are shown in Table 1.

Note 1) The following microorganisms were used.

Note 2) The following dispersant was used.

E: Ammonium salt of β-nanthalenesulfonic acid formalin condensate F: Polyoxypropylene (PO polyoxyethylene (KO) adduct of glycerin (molecular weight: 10,000)
, PO/EO molar ratio = 476) Note 3) Dry pace coal, yt% Note 4) Dry pace coal, wt'% Note 5) Stability was evaluated according to the following criteria.

○ Good stability (no coal hard cake formed) △ Stability somewhat good (some coal hard cake formed) × Poor stability (significant coal hard cake formed)

[Brief explanation of the drawing]

1 to 3 are process diagrams showing specific examples of the manufacturing method of the present invention. Applicant's agent Kaoru Furuya

Claims (1)

[Claims] 1. A coal/water slurry containing fine coal powder, water, and a dispersant is blown with air in the presence of petroleum-utilizing microorganisms that grow in a growth medium with hydrocarbons as the sole carbon source. A method for producing a stable coal/water slurry that is characterized by 2 The petroleum-utilizing microorganism is Pseudomonas
domonas), Corynebacterium (CO-r
ynebacterium), Nocardia (lJ
ocardia). Arthrobacter genus,
The method for producing a stable coal-water slurry according to claim 1, wherein the microorganism is any one selected from the group consisting of Bacillus and alkaline earth metals (A'lca-11gθnes).