JPS6117576A - Production of olefin oxide using carbide waste desulfurized with hot waste water of saponification process - Google Patents

Abstract

PURPOSE:To obtain the objective compound economically in an industrial scale, in the production of an olefin oxide by a chlorohydrin process using a desulfurized carbide waste as a saponification agent, by carrying out the desulfurization of the carbide waste using a hot saponification waste water discharged from the above reaction step. CONSTITUTION:A large amount of carbide waste is produced as an industrial waste in the production of acetylene. The waste is used as a saponification agent in the saponification of an olefin chlorohydrin to produce an olefin oxide such as ethylene oxide, propylene oxide, epichlorohydrin, etc. useful as a raw material of various chemicals, at a low cost. In the above process, the sulfur existing in the carbide waste in the form of a water-soluble sulfide (S'') and having influence to the reaction is removed or decreased easily by using the hot saponification waste water discharged from the above reaction step at a large amount. The objective compound can be produced economically by this process.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a method for producing olefin oxides using carbide binders desulfurized by hot saponification waste water.

More specifically, the sulfur sulfide contained in the carbide slag, which affects the reaction, is removed by diluting and dissolving it using warm saponification waste water discharged from the saponification reaction of olefin chlorohydrin and separating the liquids. The present invention relates to a method for producing olefin oxide by saponification of olefin chlorohydride, characterized in that the carbide slag is used in the saponification reaction.

Carbide salts are produced in large quantities when carbide and water are reacted to produce vinyl nitride, other chemical raw materials, and acetylene, which is used as a heat source. Although it is known that the main component of the carbide order is calcium hydroxide, it contains various impurities and therefore has low utility value as calcium hydroxide. Therefore, methods of disposing of it include, for example, dispersing it over a vast area and drying it by evaporating the water in the sun, or using equipment and energy to spread it over a large area. Even if treated by these methods, the layered material continues to accumulate.Some of the dried material turns into fine particles, causing problems such as deterioration of the environment, which is a problem for acetylene manufacturers. If industrially problematic waste can be effectively processed for production of olefin oxide, it will not only solve environmental problems, but also make it possible to produce on-4-fin oxide at a low cost.Olefin oxide is in high demand as a raw material for various chemicals. For example, propyleoxide is important as a raw material for propylene glycol, surfactants, polyurethane, etc.

(Prior Art) When producing olefin oxides such as ethylene oxide, propylene oxide, and epichlorohydrin by the chlorohydrin method, an aqueous solution of olefin chlorohydrin is first obtained by reacting olefin oxide and chlorine in the presence of water. It is produced by adding milk of lime or an alkali such as caustic soda to this aqueous solution, performing a saponification reaction to produce olefin oxide, and separating and purifying the olefin oxide from this reaction solution. Milk of lime is mainly used as the alkali for economic reasons. It is known to use desulfurized carbide as a substitute for milk of lime (Japanese Patent Publication No. 44-20447).
). The sulfur compounds contained in carbide are mainly Ca
There are six types: S, At2S2, and CaC2/CaS. CaS dissociates at low temperatures and is converted into H2 by water at high temperatures.
Generate S. -1u2S, readily produces H2S in both cold and hot water, and CaC2.CaS is not decomposed by water at room temperature, but is said to produce volatile organic sulfur compounds at high temperatures.

Therefore, the carbide ring contains sulfur compounds that react with S'' ions, that is, sulfide sulfur, mainly CaS.
and H2S. They exist primarily in water-soluble form. Therefore, methods of removing it by washing with water or oxidation are known. In other words, carbide 3! The desulfurized carbide tsubo obtained by adding water to dilute it and separating the water by filtration or decanting, or oxidizing it with air or other oxidizing agent to convert S to harmless SOS, 80- A method of producing olefin oxide as a saponification agent is used.

(Problems to be Solved by the Invention) In the method of producing olefin oxide using deflowed carbide, when using carbide that has been desulfurized using an oxidizing agent, the oxidizing agent must be newly added. In addition, the amount used must be strictly controlled. If the amount of the oxidizing agent added is too small, desulfurization will not be completed, and if the amount is too large, the remaining oxidizing agent may affect the yield, quality, etc. of the olefin oxide. When air is used as an oxidizing agent, a large amount of air is required. The method of diluting carbide 3-year by adding water also has problems such as requiring a large amount of water.

(Means for Solving the Problems) As a result of intensive studies to solve these problems, the present inventors discovered an effective method for removing sulfur sulfide from carbide rings by washing with water, and completed the present invention. Ta. That is, desulfurization was carried out by diluting and dissolving 3-year carbide using hot saponification wastewater discharged in the olefin oxide manufacturing process and separating the liquid.Using desulfurized Kanibaitora Deaf as a saponification agent, olefin chlorohydrin was produced. This is a method for producing olefin oxide by saponifying olefin oxide.

When producing olefin oxide using the chlorohydrin method, the aqueous solution of olefin chlorohydrin is mainly used at a concentration of 8 to 6% in order to control the by-product of dichlor and maintain economic efficiency.
A low concentration solution is used.

Moreover, an alkaline aqueous solution is also used in the reaction as a 10 to 20% aqueous solution. If the olefin oxide produced in the saponification reaction is not quickly separated from the reaction system, glycol by-products will rapidly increase, causing a decrease in the yield of olefin oxide. For this purpose, the olefin oxide is expelled from the reaction system while blowing a large amount of water vapor into the reaction solution.

The amount of water charged in the saponification process is 30 to 80 tons per ton of olefin oxide, including blown steam, and most of the water is discharged from the bottom of the saponification reactor at a temperature around the boiling point. Ru. The alkali used in this case is 1.3 to 2.5 tons of calcium hydroxide. -f′, that is, carbide 3 used in the saponification reaction
diluted with warm saponification waste liquid discharged in large quantities,
The aqueous layer can be separated by filtration or declination to remove and reduce the S'' contained in carbide 3. The carbide 3 used in the method of the present invention is a suspension discharged from the acetylene process and its suspension. Applicable materials include sludge obtained by separating a turbid liquid and settling it, and sludge obtained by inverting the layers in a mud pond, etc. Warm saponification waste liquid used as dilution water, waste liquid as it is, and waste heat recovery are used. Use all or part of the liquid after washing, static separation, supernatant liquid, etc.

In the method of carrying out the present invention, carbide particles and hot saponification waste liquid are placed in a dissolution tank and mixed with stirring to disperse carbide particles whose main component is calcium hydroxide. After that, I spoke,
Alternatively, there is a batch processing method in which the liquid is left to separate and the aqueous layer is extracted, or a thickener is continuously charged with carbide carbide and hot saponification waste liquid, and while the upper layer supernatant liquid is continuously extracted, the liquid is separated from the bottom. A continuous processing method can be used to extract the sulfurized carbiton falcon. Alternatively, the aqueous layer may be separated by using a method such as passing the solution through the mouth. If necessary, water is added to the carpai tochi desulfurized by these methods to adjust the concentration to 10 to 20%, and the mixture is subjected to a saponification reaction.

(Functions and Effects) S'' in the carbide ring is contained in an amount of 0.5 to 2% in a dry process and 005 to 0.2% in a wet process, and is mainly present in a water-soluble form.

Calcium hydroxide, the main component in carbide 3 and a half, is almost insoluble in water. Although the hot ionization waste liquid contains a few percent of calcium chloride and unreacted calcium hydroxide as well as a small amount of impurities, it can completely dissolve and disperse S''.The specific gravity of calcium hydroxide is approximately 2.08-2. 64, and the specific gravity of the hot saponified wastewater supernatant liquid is approximately 1.The calcium hydroxide diluted with the hot saponified wastewater and mixed and stirred will easily settle when left to stand, forming a mud phase in the lower layer. The sedimentation rate of calcium hydroxide becomes significantly faster at higher temperatures due to the viscosity of the aqueous phase.

It goes without saying that the S concentration in the desulfurized carbide is highly dependent on the S concentration in the carbide ring used, but the amount of hot saponification waste used for the carpa-ide slag and the Depends on the amount of water layer. For example, disposition 0.
When 15 tons of a semi-aqueous solution of carbide horse chestnut containing 1% calcium hydroxide and 10% calcium hydroxide were diluted with 50 tons of hot saponification waste liquid supernatant, mixed, stirred, and allowed to separate, 15 tons of a carbide horse aqueous solution containing 10% calcium hydroxide was obtained. The concentration of S'' in the aqueous solution is 0.023
%. In addition, in the above operation, if the liquid is allowed to stand still and most of the supernatant liquid is extracted, a mud phase of about 3.75 mm containing about 40% calcium hydroxide is obtained, and water (S to non-containing) is added to this mud phase. In addition, when a 10% solution is used, S' concentration becomes 0.0058%. The aqueous desulfurized carbide solution from which S'' has been removed and reduced in this manner is used as a saponification agent for olefin chlorohydrin, and the resulting olefin oxide exhibits a yield almost equivalent to that obtained when milk of lime is used.

According to the method of the present invention, the carbide stop in the acetylene generation process can be easily desulfurized with the hot saponification waste liquid discharged from the olefin oxide manufacturing process and can be used as a substitute for lime milk, so that acetylene manufacturers can easily treat and dispose of it. It is possible to effectively consume carbide waste, which is a difficult industrial waste, and to produce olefin oxide with industrial advantage.

(Example) Hereinafter, the method of the present invention will be explained in detail with reference to Examples and Comparative Examples.

Example-1 Using a desulfurization tank equipped with a stirrer with the extracted pulp attached to the 1rrI position of a cylindrical container with a diameter of 1.8 m and a height of 2.0 m, S'' content of 0.12% and Ca ( OH)g 1.3
．． Four tons of carbide aqueous solution containing 1% were charged. After one hour of standing, the pulp to be extracted at a position of 1 m was opened and the supernatant liquid was extracted. After that, the heated saponification waste liquid supernatant liquid 5 at 80°C
0 ton was added and stirred for 10 minutes, left undisturbed for 30 minutes, the supernatant liquid was extracted from the pulp at 1 g position, and 3 tons of hot saponification waste liquid was added again and stirred to obtain a desulfurized carbide aqueous solution. This desulfurized carbide contains 12.9% Ca (OH
)2, and the S concentration was less than 10 ppm.The column was 300 m in diameter and had a 4-stage reaction section with a sheep tray as a leak tray and a 2-stage recovery section with a sheep tray and an overflow section Z. The reaction was carried out using a column-type multi-stage reactor.

A 4.25% propylene chlorohydrin aqueous solution at 80°C was charged at a flow rate of 1,490 Kf/h, the desulfurized carbide aqueous solution at 70'C was charged at a flow rate of 482 Ky/h, and steam from the saponifier pot was 121 Kg/h. The crude propylene oxide that came out was purified by distillation to obtain purified propylene oxide of 38.9 Ky/hr. The yield of propylene oxide was 98.1%.

Comparative Example-1 Using the reactor used in Example-1, a reaction was carried out using the raw materials of Example-1 except for the desulfurized carbide stationary aqueous solution.

Propylene chlorohydrin aqueous solution 1.457Ky/
At a flow rate of hr, S''min o, 12%, Ca(OH) at room temperature
448Kg of carbide aqueous solution containing 213.1%
Purified propylene oxide, 33
, 7 Ky/hr was obtained. The propylene oxide yield was 88.6%.

Reference Example-1 Using the reactor used in Example-1, a reaction was carried out using the raw materials of Example-1 except for the desulfurized carbide potato aqueous solution. Propylene chlorohydrin aqueous solution 1,510;/h
Milk of lime containing 212.7% Ca (OH) was charged at 70°C with a flow rate of 475 Kf/h, and water vapor 1
The reaction was carried out while blowing 23~/h of purified propylene oxide, yielding 1.7 kg/h of purified propylene oxide. The propylene oxide yield was 98.2%.

Example-2 In the desulfurization tank used in Example-1, 0.08% of S was added at room temperature.
, 1 ton of carbide tsubo aqueous solution containing 14.2% of Ca (OH) 2 and 3.5 ton of supernatant liquid of hot saponification waste liquid at 80° C. were charged, stirred and mixed for 10 minutes, and then allowed to stand for 60 minutes.

After that, 1 g of pulp was extracted, the pulp was opened, and the supernatant liquid was extracted and used as a desulfurized carbide potato aqueous solution.

This solution contained 160 ppm of S'', 'Ca (
OH) 215.2%, and the temperature was 65°C.

A saponification reaction was carried out using the same raw materials and equipment as in this desulfurization car. Propylene chlorohydrin aqueous solution 1,505
Desulfurized carbide acid aqueous solution 462 kg/hr flow rate
The purified propylene oxide was charged at a flow rate of Kt/h, and the reaction was carried out while blowing steam at 125~/h.
Kg/h was obtained. Propylene oxide yield is 97.4
%Met.

Example-3 In the current tank used in Example-1, S″ content of 008% at room temperature,
1 ton of aqueous carbide solution containing 14.2% Ca(0,p)2 and 0.52% Ca(OH)2' at 92°C.
3.5 tons of saponification waste liquid containing was charged, stirred and mixed for 10 minutes, and then allowed to stand for 60 minutes. Thereafter, the extracted pulp at the 1rn' position was opened and the supernatant liquid was extracted to obtain a desulfurized carbide rod aqueous solution. This solution contains 150 ppm of S'', C
It contained 15.6% a(OH)g and the temperature was 71°C. The reaction was carried out using the same raw materials and equipment as in Example-1, except for using this desulfurized carpaiton semi-aqueous solution.

A propylene chlorohydrin aqueous solution was charged at a flow rate of 1.485 Kg/h to a desulfurized carbide aqueous solution 385 at a flow rate of 9/h, and the reaction was carried out while blowing into steam 131 at a flow rate of 9/h to produce purified propylene oxide 3B, 2 Ky/
I got h.

The yield of propylene oxide was 97.5%.

Example-4 Ca concentrated in a mud pond was added to the desulfurization tank used in Example-1.
Charge 0.3 tons of carbide mud containing 251.2% (OH), 41% S and 80°C heated saponification waste liquid supernatant liquid 3.5) y, stir for 30 minutes, and then mix for 60 minutes. After that, the extracted pulp at the 1 ml position was opened and the supernatant was extracted to prepare a desulfurized carbide 3y aqueous solution. This solution contained 290 ppm of S, Ca (OH) and
'4.2%, and the temperature was 72°C. A saponification reaction was carried out using the same raw materials and equipment as in Example-1, except that this desulfurized carbide stationary aqueous solution was used as the raw material. The propylene chlorohydrin aqueous solution was charged at a flow rate of 1,510 Kg/h and the desulfurized carbidedonte aqueous solution was charged at a flow rate of 455 Ky/h, and the reaction was carried out while blowing 118 Kg/h of water vapor to produce purified propylene oxide at 37.6 Kr/h. Obtained. The propylene oxide yield was 95.6%.

Example-5 A 6.0% propylene dichlorohydrin aqueous solution at 80°C was added to the reactor of Example-1 at a flow rate of 6.100 V4/h, and 1.
The water vapor was charged at a flow rate of 870 Ky/hr and the water vapor was
A saponification reaction was carried out while blowing Kg/h, and the wetted crude epichlorohydrin was purified by distillation to obtain 257 Ky/h of purified epichlorohydrin. The yield of epichlorohydrin was 97.9%.

Claims (1)

[Claims] 1) When producing olefin oxide through the saponification reaction of olefin chlorohydrin, the sulfur sulfide contained in the carbide slag is removed using hot saponification waste liquid discharged from the saponification reaction of olefin chlorohydrin. A method for producing olefin oxide, characterized in that carbide slag subjected to a reduction treatment is used in a saponification reaction.