JPS62135592A - Additive for aqueous slurry of solid fuel - Google Patents

Abstract

PURPOSE:To provide the titled additive capable of providing a slurry having a low viscosity even at a high concn. of a solid fuel and excellent stability even when allowed to stand for a long period of time, which comprises a salt of nitrohumic acid as the effective component. CONSTITUTION:An effective component consisting of a salt of nitrohumic acid is obtd. by pulverizing lignite, peat, brown coal or the like, oxidizing the pulverized product, filtering the reaction mixture, neutralizing the precipitate with a hydroxide of an alkali (earth) metal, NH3, or a lower amine. The component is blended with a surfactant, gelling agent, an anti-rust agent, a preservative, an anti-foaming agent, or the like, if necessary, to obtain the titled additive. The additive is added in such an amt. as will provide an effective component concn. of 0.01-5wt% to an aqueous slurry of a solid fuel contg. a powder of a solid fuel, such as (deashed) coal or coal (carbonized) coke, dispersed in water. This provides a low viscosity and a stability for a long period of time even in the case of a high-concn. slurry having a solid fuel concn. of, e.g., 65-75wt%.

Description

[Detailed Description of the Invention] [Industrial Application Field 1] This invention is applicable to coal, deashed coal, carbonized coal coke,
The present invention relates to an additive for solid fuel water slurry useful for fuels made by dispersing solid fuel powder such as petroleum coke in water.

[Prior Art] Solid fuels such as coal have long lost their place as fuel to petroleum due to their solid shape.
In the wake of the oil crisis, solid fuels were reviewed, and there have been many attempts to treat solid fuels as fluids by mixing solid fuel powder with a medium, as exemplified by coal-oil mixed fuel (COM). is being carried out.

However, in the case of coal-oil mixed fuel, it is impossible to avoid the disadvantage that about half of the fuel is oil, and there is a desire to develop another slurry fuel.

In recent years, slurry, a fluid made by using water as a medium and dispersing solid fuel such as coal or petroleum coke at high concentrations, has become suitable for transportation by pipeline or oil tanker, and it has also become suitable for transporting oil in various boilers. Attempts are being made to use it as an alternative fuel or raw material for gasification. In the case of this slurry, since the medium is water, it is preferable that the slurry has the following properties: high concentration of solid fuel powder, low concentration of solid fuel powder, and agglomeration of solid fuel powder. It has excellent long-term stability without causing sedimentation or sedimentation.

By the way, it is already known that various additives such as rust preventive agents, antioxidants, and dispersants are added to the slurry in order to modify the characteristics of the coal-water slurry. However, among these known additives, very few have been found that give very good results on the solid fuel powder concentration or viscosity and also satisfy both this property and the stability of the slurry. For example, U.S. Pat. No. 2,346,151,
Japanese Patent Publication No. 55-45600 and Japanese Patent Publication No. 54-16
Additives such as phosphoric acid esters, various amines, reaction products of alkylene oxides with alkylphenols and naphthols and acidic phosphates, and salts of polycarboxylic acids such as polymethacrylic acid disclosed in Japanese Patent Application No. 511 etc. It is difficult to obtain a highly concentrated slurry due to its poor degrading function.

Also, JP-A-52-71506 and JP-A-53-5
lignin sulfonate proposed in JP-A No. 81, JP-A No. 56-21636; proposed naphthalene sulfonate and salts of formaldehyde condensates of naphthalene sulfonic acid; proposed in JP-A-56-57889; For example, octene-maleic anhydride copolymer II
Copolymers such as Jium salts have a viscosity-lowering function compared to the above-mentioned additives and contribute to the stability of the slurry to some extent, but these properties still have room for improvement and are not sufficient. No, no.

Particularly recently, attempts have been made to deash coal and use it as a water slurry as fuel for general industrial boilers. Since this problem is more likely to occur, there is a strong need for measures to solve this problem.

[Problems that the invention attempts to resolve] This invention has a superior viscosity-reducing function compared to the above-mentioned conventional products, and also has good results in terms of long-term stability of deashed coal-water slurry. The purpose of the present invention is to obtain an industrially useful additive for solid fuel water slurry.

[Means for solving problems]

As a result of intensive studies to achieve the above object, the inventors found that an additive containing nitrofumate as an active ingredient has the ability to reduce the viscosity of solid fuel water slurry IJ-1, especially deashed coal water slurry, and stabilize the slurry. They discovered that it can give good results to both men and women, and came up with this invention.

That is, the present invention relates to an additive for solid fuel water slurry characterized by containing the nitrofumate as an active ingredient.

[Structure/Action 1 of the Invention The additive of the present invention contains a nitrofumate as an active ingredient, and this active ingredient is usually produced by the following method. That is, young coals such as lignite, peat, and brown coal are crushed, oxidized by adding nitric acid, and filtered to separate into precipitate and e-liquid. Then, the above precipitate was treated with an alkali metal,
It can be obtained by neutralizing with alkaline earth metals, ammonia, and lower amines to obtain nitrofuminic salts.

Alkali metals include potassium hydroxide and sodium hydroxide; alkaline earth metals include magnesium hydroxide and calcium hydroxide; lower amines include alkylamines such as methylamine, ethylamine, and propylamine; Preferred are alkalamines such as monoethanolamine and triethanolamine.

In addition to the active ingredient consisting of the above-mentioned nitrofumate, the additive of the present invention may contain surfactants that have been proposed in the past, and may also contain gelling agents, rust preventives, preservatives, etc. as necessary. If foaming is observed, an antifoaming agent such as an aliphatic alcohol or a silicone compound may be used in combination.

The amount of the additive of the present invention configured as described above added to the solid fuel water slurry varies depending on the characteristics of the slurry, that is, the particle size and concentration of the solid fuel powder, the type of the active ingredient itself, etc. One role is that the active ingredient is 90.01 to 5% by weight of the slurry, particularly preferably 0.05% by weight.
It is best to rub it to a concentration of ~1% by weight. As the amount added increases, the viscosity lowering effect becomes greater and better results are obtained in terms of stability. However, if the amount exceeds a certain level, no further effect can be expected, which is economically disadvantageous.

The method of adding the additive is arbitrary, and an appropriate method may be selected depending on whether the solid fuel powder is obtained by dry pulverization or wet pulverization. For example, in the dry pulverization method, it is preferable to add and mix the additive of the present invention in advance into water in which the pulverized powder is to be dispersed, and then add and mix the pulverized powder thereto.

On the other hand, in the wet pulverization method, it may be added in advance to the water used for wet pulverization, or it may be added during or after wet pulverization.

In addition, if it is difficult to obtain a stable slurry by using additives and submerging in water or stirring with a regular impeller, mix using a stirrer with strong shearing force such as a homogenizer or line mixer. It is better.

Solid fuels to which the additive of this invention is applied include coal,
There are petroleum coke and coal carbonized coke, and the coal may be sub-bituminous coal, bituminous coal, anthracite coal, etc., and there are no particular restrictions. Moreover, these deashing coals are also used. Whether these solid fuels are pulverized by a dry pulverization method or a one-type pulverization method to form a powder for water slurry, and the particle size of this powder is not particularly specified. However, it wears out during pipeline transportation and burner combustion.

In order to avoid problems such as clogging, it is usually preferable that the 200 mesh pass be 50% by weight or more.

[Effects of the Invention] The additive for solid fuel water slurry of the present invention exhibits an excellent viscosity reducing function, and usually contains 65 to 75% by weight of solid fuel.
This makes it possible to prepare a slurry that exhibits a relatively high concentration and low viscosity. Moreover, this slurry exhibits excellent stability with no solid particles settling during long-term storage. In particular, the same effect as described above can be achieved even when solid fuel or demineralized lime is used, which is a far superior performance compared to conventional additives.

Therefore, according to the additive for solid fuel water slurry of the present invention, solid fuel water is industrially advantageous because it is easy and economical to transport by pipeline or other means, and it is easy to supply to combustion equipment. Slurry can be provided.

[Example 1] Examples of the present invention will be described below to explain more specifically.

The coal used as the solid fuel in Example 1 below was Australian Newland coal deashed by flotation to have an ash content of 3% by weight. It goes without saying that ordinary coal without deashing is also effective.

Furthermore, the viscosity and static stability of the solid fuel water slurries obtained in the following Examples and Comparative Examples were measured as follows. First, the viscosity of the obtained solid fuel water slurry (25°
C) was measured using a B-type viscometer, and the stationary stability was investigated using the following method. That is, a stainless steel cylinder with a diameter of 5 cm and a height of 20 mm was provided with an outlet with a stopper at a position 6 cm and 12a from the bottom, and the obtained solid fuel water slurry was poured into the cylinder to a height of 18 cm from the bottom. It was left standing at room temperature for 3 weeks. Next, divide the cylinder into an upper layer above 12 cm, a middle layer of 6 to 12 cm, and a lower layer below 6 cm, and reduce the solid content of each layer to 10 cm.
Measurement was performed by the loss on drying method of leaving the sample in a dryer at 5°C for 2 hours.

Example 1 Newland coal with an ash content of 3% by weight obtained by deashing was dry-pulverized to obtain coal powder with a 200 mesh pass of 75% by weight. Using this powder, additives of the present invention and comparative additives shown in Table 1, and the required water, these were thoroughly stirred and mixed to obtain a deashed coal-water slurry composition with a solid content of 70 Mm%. . The viscosity and static stability of each of the obtained slurry compositions were as shown in Table 1. In addition, the concentration of each additive's effective content in the slurry is also listed in the same table.

Example 71 Example 2 Petroleum coke was crushed to obtain petroleum coke powder containing 200 mesh passes of 80% by weight. A petroleum coke water slurry composition having a solid content of 75% by weight was obtained by thoroughly mixing this powder, additives of the present invention and comparative additives shown in Table 2, and water. Table 2 shows the results of measuring the viscosity and static stability of each of the obtained compositions.

In addition, the concentration of each additive's effective content in the slurry is also listed in the same table.

From the results in Tables 1 and 2 above, it is clear that the additive for solid fuel water slurry of the present invention has low viscosity and excellent static stability despite the high concentration of solid fuel powder. It is clear that a solid fuel water slurry is obtained.

Claims (1)

[Scope of Claims] 1) An additive for solid fuel water slurry characterized by containing a nitrofumate as an active ingredient. (2) The additive for solid fuel water slurry according to claim (1), wherein the nitrofumate is an alkali metal salt, an alkaline earth metal salt, an ammonium salt, or a lower amine salt. (3) Claim No. 1 in which the solid fuel is coal, deashed coal, carbonized coal coke, or petroleum coke.
Additive for solid fuel water slurry according to item 1 or item 2.