AU421663B2 - A device and a method for making calcium carbide - Google Patents

Description

invc;ion rel.at to a i:iethod and a device or kin! j cal.:i continuously and directly f.i -in i cal c ui/natorial stone, slaked lime, or quick lime) and car-ol mater-'il, ond more particularly

to a method and a device for imnking calcium carbide by placing starting lime stone and coke in an eccentrically movable vessel, injecting and burning an oxygen-acetylene

mixture in the vessel, while enclosing the mixture thus injected with an oxygen jet curtain, and forming a heat- insulating protective air curtain along the inner surface of side wall of the vessel, whereby calcium carbide is continuously and directly formed from the lime stone and the coke.

According to a conventional method of making

calcium carbide, calcium oxide is made by heating lime

stone in a lime furnace together with coke placed therein,

and the calcium oxide thus prepared is heated in an electric furnace together with coke for making the desired calcium

carbide.

The chemical formulae for such reactions are

generally expressed as follows.

In the lime furnace CaCO3 CaO CO 2 (1) In the electric furnace CaO 3C CaC 2 CO..(2)

Thus, the conventional method for making calcium

carbide is a kind of two-step process, and complicated

treatment of the material has been necessary, which is generally costly due to the large man-hours required thereby. As an important use of calcium carbide, acetylene

has been produced by using the reaction between calcium carbide (CaC 2 and water (zO20). The preparation of

1q (71 acetylene gas from calcium cri has increasingly been

replaced by a new thermal cracking process (partial oxidation)

using natural gas or other hydrocarbons naphtha).

The reason for such change in the process for making acetylene

gas is mainly in the high cost of electricity which assumes

about one half of the acetylene cost, in the case of the

carbide process.

Carbide residuum has been used for regeneration

of carbide by mixing it with coke and heating in the electric

furnace. Such regeneration from the carbide residuum

has been rather uneconomical, judging from its yield and

man-hours necessary for handling the materials.

Therefore, an object of the present invention

is to obviate the aforesaid difficulties of conventional

process for making calcium carbide with electric furnace,

by providing a method and a device for making calcium

carbide directly from lime stone without using any electric

furnace. For instance, an embodiment of the method according

to the present invention comprises steps of placing lime

stone and coke in a reaction vessel, injecting the burning

flame of a fuel mixture of a hydrocarbon and oxygen on

the top surface of the material in the vessel, melting

both the coke and the lime stone by the,.flame of the fuel

mixture for causing them to react with each other, translating

the vessel along a circular path with a center offset

from the axis of the vessel itself for agitating the molten

mixture of lime stone and coke while maintaining the injection

of the fuel mixture, forming an oxygen curtain surrounding

the fuel mixture for burning a carbon-monoxide-rich gas

generated by the reaction between lime:stone .and coke to

421,663

27 3I1171 the temperature of the moltcn mixture by the

ol ofhe e on-'g.-o.oxtde.-rioh gAz, and forming a .eat-ii-ulating air curtain along the inne- surface of :-ide wall of the vcssel for its protection.

The chemical reaction of the aforesaid process of the present invention. can be given by the following relation, which is a combination of the formulae (1)

and

CaC0 3C CaC 2 C02 CO 254.25 Kcal. The inventor has analyzed the gaseous atmosphere

in an electric furnace and found that the composition

of such gaseous atmosphere is as follows.

Carbon dioxide (Ca 2 30% by-volume Carbon monoxide (CO) 67% by volume Nitrogen (N2 3% by volume It should be noted that the combustion of

1 Kg of carbon to carbon monoxide generates 2,500 Kcal

of heat, while the combustion of 1 Kg of carbon to carbon

dioxide generates 7,830 Kcal of heat, so that the combus-

tion of monoxide gas to dioxide gas, in the chemically

equiVal-ent amount of 1 Kg*-f carbon, will genefate

5,290 Kcal of heat energy.

Thus, according to a preferred embodiment of

the process of the present invention, the starting

material consisting of lime stone and coke is melted

by the flame of a fuel mixture' of oxygen and acetylene,

and at the same time, the carbon monoxide gas generated

by the reaction of the lime stone with the coke is burned by forming an oxygen curtain surrounding the fuel mixture,

so as to heat the lime stone and coke at 2,5000C to

42L663

27. 311171 3,5000C. The translation of the vessel along a closed path results i~n an efficient agitation of thc starting

material and increases the effective contact area between

the starting material hieforming very hot flames

of the fuel mixture and the carbon-inonoxide-rich gas.

.Whereby, the heat energy which is available from the

fuel mixture of acetylene, and oxygen is fully utilized,

for accelerating the melting of the starting material as well as the chemical reaction of the lime stone with the coke. In the foregoing description, lime stone and coke are used as the starting material, but any other suitable calcium material and .abe*-material can be

used in the present invention for the production of calcium carbide. For a better understanding of the invention, reference is made to the accompanying drawings, In which: Fig. 1 is an elevation, with a part cutaway, of a device for making calcium carbide, according to the present invention;. Fig. 2 Is a plan view of the device of Fig. 1; Fig. a partial enlarged sectional view of a 3 irs' fuel injecting nozzle, usable in the device of Fig. 1; .Fig. 4iis a horizontal sectional view taken along the line IV-IV of Fig. 3;_ Fig. 5 is a vertical sectional view of a supporting cylinder of a framework In an embodiment of the present invention, which support cylinder is suitable for alternately translating the framework along a closed path in opposite directions; 421.66-3

27.3117 6 i. .anvieWq siilar to Fig. 1, illustratIng h r'ebodiment h of the ivention; Iresent and Fig. 7 is an enlarged sectional view of fuel o in the e:bodtrent or Fig. 6. Like parts are designated by like numerals and

Zy-lhbols throughout the drawings.

A device for making calcium carbide, according to thc present invention, as shown in Figs. 1 to 5, comprises a substantially cylindrical vessel 1 for melting a starting material consisting of calcium and carbon materials, lime stone and coke, an agitator 2 for translating the vessel 1 along a closed path so-as to cause the molten material in the vessel to swirl eccentrically therein for agitating the material, an injector 3 for injecting the flame of a fuel- gas-oxygen mixture toward the starting material placed in the vessel 1 and for injecting an oxygen curtain surrounding the injected flame of the fuel-gas-oxygen mixture, and an air injector 4 for producing an air curtain along the inner surface of side wall of the cylindrical vessel 1 for protect- ing the wall of the vessel from the high temperature generated by._the-injected flame of the fuel-gas-oxygen mixture surrounded by the oxygen curtain. Although the temperature of the molten material at the central portion of the vessel 1 can reach as high as 2,500'C to 3,500 0 c, with the aid of such protective air curtain, which is designated by a reference numeral 31 .in Fig. 1, fairly inexpensive refractory material, such as chamotte, can be used for lining the inner surface of the cylindrical wall of the vessel 1. The agitator 2 of the device of the invention can be a unitary Member which is capable of supporting and

421663 translating the vessel 1along a closed path for the purpose of the agi tation of the molten materiai in the- vessel, or it can consists of' a plurality of in-dividual supporting member,-; which cooperate witLh each other for fulfilling the similar function as the aforesaid unitary member. The translation of the vessel 1 for the agitation of the material can be a unidirectional motion or a motion of which direction is changed reversely or angularly. The agitator 2 of the illustrated embodiment consists of a substantially square framework 5 holding the vessel 1 by means of four clamps 6, as shown in Figs. 1 and 2. The four corners of the substantially square framework are movably supported on a base 8 by means of four support cylinders 7a to 7d (to be collectively referred to as respectively. Fig. 5 illustrates, in vertical section, a typical construction of the support cylinder 7. Each- support cylinder 7 has a cylindrical casing 9 secured to the base 8 by a suitable means, by welding. A cylindrical rotary member 10 is rotatably fitted In the casing 9, while inserting bearing balls 11 between the bottom surface of the rotary member 10 and the b6ttom wall'of the casing 9, for ensuring smooth rotation of the rotary member 10 in the casing. An eccentric *vertical shaft 141 (more particularly, 141a, 14b, 14c or 14d) Is rotatably secured to the upper end of the rotary member 10, with its vertical axis offset from the vertical axis of the rotary member 10, so that as the rotary member 10 rotates in the' casing 9, the vertical shaft 14Jrotates about the axis of the rotary member

42L.663

The d.itance D between the axib B--B of the vertical shaft :ni 1-ihe axis A- o. lhc rotary: member corresponds to the radius of the circular path of the vessel 1 during the desired circular translation of the framework together with the vessel 1.

In the preferred embodiment of the invention, as shown in Fig. 5, the vertical shaft 14 is supported by a boss 12 integrally secured to the rotary member 10, and suitable bearings 13 are inserted therebetween. A cover is provided for protecting .the bearings 13 from dust particles and other risks of contamination from the outside. With the construction of Fig. 5, it is apparent that-the vertical shaft 14'can spin by itself while travelling about the axis A-A of the rotary member

Four seat members 16a, 16b, 16c, and 16d (to be

collectively referred to as are secured to the lower surface of the framework 5 for receiving the upper ends of the vertical shafts 14a to 14d, as shown in Fig. 1. The seat member 16 maintains operative engagement with the

upper end of the vertical shaft 14, so that the circular movement of the rotary member 10 and the shaft 14 is

transmitted to the- framework 5.for causing the latter to translate along the aforesaid circular path together with

the vessel 1.

To drive the circular translation of the framework

and the.vessel 1, one of the "four rotary members 10, e.g., in Figs. 1 and 2, has a bevel gear 17 secured to the upper end thereof, which bevel gear 17 operatively.meshes with another bevel gear 18 secured to the rotary shaft of

a driving motor 19.

421.6 6 3 8.-

For simplicity's te agitator 2 is illustrated as a means for translating the vessel 1

along a circular path, but the shape of the path is not

limited to a circle. For instance, by using a suitable cam means instead of the eccentric vertical shaft 14 of Fig. 1, the vessel can be translated along a closed path of any desired configuration, such as an elliptic path. Similarly, the number of the support cylinders 7 and the rotary members 10 is not limited to four, respectively, as illustrated in Figs. 1 and 2. In fact,

the vessel 1 can be movably supported by one support cylinder 7, or by any suitable number of support cylinders 7, by slightly modifying the structure of the framework 5 or the bottom of the vessel 1, in a manner known to those skilled in the art. Referring to Figs. 3 and 4, the injector 3 consists of a-series of concentrically disposed cylindrical passages; namely, a central oxygen passage 20, a fuel passage 21 for delivering fuel, such as acetylene, a second oxygen passage 20', a pair of cooling water passages 22 for circulating cooling water by feeding cold water through one of the passages 22 while returning the warmed water through the other one of the passages 22, and a surround- ing oxygen passage 23 for delivering oxygen to produce an oxygen curtain. The concentric passages are disposed in the aforesaid order so as to surround the central oxygen passage 20. A mixing chamber 24 is formed at the lower end of the injector 3, which directly communicates with the central oxygen passage 20, through a nozzle 25 formed *at the lower end of the passage 20. The nozzle 25 is to

421. 63

2 7 3 1 The i .jct oxygen in the form of a jet. very lower ends of i 01 pas1:aag: 21 and fti- second oxygen passage 20' are clc::;ed, and suitable openings 26 and 27 are bored in the ur:o.J-nmJty of the lower ends of the passages 21 and respectively, so as to inject an oxygen-rich fuel-gas .mixture into the mixing chamber 24.

With the aforesaid arrangement of the oxygen

passages 20, 20' and the fuel passage 21 in the injector 3, the fuel and oxygen are delivered separately through the injector, until they are injected into the common mixing chamber 24. Such separate delivery of the fuel and oxygen

completely eliminates the danger of back fire and ensuing

explosion, which have been rather frequently experienced

with conventional acetylene gas burners.

Oxygen curtain nozzles 28 are bored at the lower end of the surrounding oxygen passage 23, so as to direct

an oxygen curtain 39 obliquely downwardly away from the axis of the injector 3. The oxygen curtain 39 thus formed acts to surround a flame 38 of the fuel-gas-oxygen mixture from

the mixing chamber 24..

The injector 3 has a lower end plate 29 which is

exposed to the heat from the flame 38 of the fuel-gas-oxygen

mixture, but it can be made of a common metallic material

without using any special heat-resistant metal, thanks to the cooling by the cold water flowing through the cooling

water passages 22.

In order to form the protective air curtain 31

in front of the inner surface of the vertical side wall

of the vessel 1, a toroidal air passage 4 is horizontally

disposed at the unper end of the vessel 1, as shown in

421.6 63

27. 311i Fig. 1. A substantially annular opening 30 is bored on

the lower Inner portion of the air passage 4, in such a

manner that the air in the passage 4 is injected into the

vessel 1 in the form of a curved plane covering the inner

surface of the vertical side wall of the vessel. Due to

the heat-insulating properties of the air, the air curtain

31 thus formed protects the refractory material of the

side wall of the vessel from the extremely hot molten

material located at the central portion of the vessel 1.

In the illustrated embodiment, the toroidal air passage

4 is secured to the vessel 1 by four holders 33 through

hinges 32. To ensure the reliable connection between the

holders 33 and the air passage 4, a plurality of bolts 34

may be used, as shown in Figs. 1 and 2. The connection

of the toroidal air passage 4 to the vessel 1, however,

is not restricted to such holders and hinges. In fact,

any other suitable joints can be used for securely

connecting them. The use of the hinges 32 is advantage-

ous, because with hinges, the air passage 4 can easily

be replaced. A plurality of air pipes 35 from an air

source (not shown) are connected to the toroidal air

passage 4, for the purpose of.supplying air under pressure

to the passage 4.

The starting material for calcium carbide

according to the present invention, lime stone and

-coke, -should preferably be in the form of medium sized

particles, although big lumps or fine granules of the

material can also be processed in the device of the

invention. Slaked lime and/or quick lime can be mixed

with the lime stone, as a- part of the calcium source

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Jc desired alc:lurl carbide. According to the preferred fo-,mC of I! nvent:o:,, cli materia 36 nl1c d in e anr n d then coke 37 is n--erial. pI:ace on the top the calcium a~s shown in "'ig.i r-aterial, as s1, in lpig. It is also posible to mix the coke 37 vith the calcium materilal 36 before placing them in the vessel 1. In the case of 1, coke 37 on the calcium material 36 is directly heated by the flame 38 of the fuel-gas-oxygen mixture delivered from the mixing chamber 21 of the injector 3, until the coke 37 becomes white-hot. With the coke 37 heate.d white-hot, air valves (not shown) is operated to feed compressed air to the air passage 4 for projecting curtain 31 from the air the annular opening 30 so as to spread it along the inner surface of the vertical wall of the vessel 1. The driving motor 19 is started to drive the aforesaid translation of the framework 5 and the vessel 1, through the bevel gears 18, 17, the support cylinders 7, and the seat members 16. Thus, the white-hot coke 37 is thoroughly mixed with the calcium material 36, in response to the Stranslation of the vessel-l, so that the heat energy carried by the white-hot coke 37 is transferred to the calcium material 36. At the same time, the flamne 38 of the fuel-gas-oxygen mixture acts to heat the mixture of the coke and the calcium material, which are agitated by the translation of the vessel. Whereby, the mixture of the coke 37 and the calcium material 36 is melted. The fuel gas, which is to be used in the fuel- gas-oxygen mixture at the mixing chamber 24, is a hydro- carbon, such as acetylene, propane, and heavy oil. With the flame 38 of the fuel-,gas-oxygen mixture, an extremely

421.663

2.3I1~ high temperature can be achieved in a very short time. As the te:f!-nerature of the materials at the central portion of the vessel 1 exceeds a certaM. level,

a large amount of carbon monoxide gas is generated in the form of a bluish white flame. When such bluish whiLte flame Is generated, an oxygen valve (not shown) controlling the oxygen passage 23 is operated, so as to blow the oxygen curtain 39 through the oxygen curtain nozzles 28 of the injector 3. As a result, the carbon monoxide gas of the bluish white flame is burned by the oxygen of the curtain 39. Such combustion of carbon monoxide gas acts to further raise the temperature of the mixture of the calcium

material and the carbon material. The agitation of the molten material through the circular translation of the vessel 1 acts to thoroughly mix the molten material,- whereby gaseous impurities dissolved in the molten material, such as sulfur, is expelled from the liquid phase material, not only from the top surface of the liquid-phase material, but also from deeper portions thiere of. Consequently, highly homogeneous calcium carbide of high purity can be obtained. Only one injector 3 is shown in the embodiment of Figs. 1 to 5, but the number of injectors to be incorporated in the device of the Invention is not restricted to one. -In fac-t, a plurality of suach injectors can be used for making a comparatively large amount of calcium carbide at a time. Figs. 6 and 7 illustrate another embodiment of the present invention, which includes three injectors 3

4ZL663 c'.oc ,d at ,'f1i.ces of an cw ulat era1 tri angle, in 3yvmetI y .with each other, relative to the axis of a vessel 1. Referring to Fig 6, t,.e three injectors 3 artl secured to walls 40 of a belt-like triangular oxygen p,,assage Ill at the inside corner& of three vertices thereof, respectively. Three separate oxygen feeders 23 are connected to the top of the oxygen passage 41. A Plurality of oxygen curtain nozzles 28 are bored at the bottom of the triangular oxygen passage 41, as can be seen from the figures. Accordingly, three flames

38 of the fuel-gas-oxygen mixture from the three

injectors 3 can be surrounded by a triangular oxygen curtain 39 from the triangular oxygen passage 41.

In the embodiment of Figs. 6 and 7, it is not

necessary to use separate surrounding oxygen passages in each of the injectors 3. The single oxygen passage 41,

as shown in the figures, will be sufficient.

If a large amount of the starting material, con-

sisting of calcium material 36 and carbon material 37,

is placed in the vessel 1, the agitator 2, especially the

framework 5 thereof, is exposed to a very heavy load.

At the same time, the support cylinders 7 are subjected

to heavy thrust load. In order to reduce the load to

the framework 5 and the support cylinders 7, a plurality of pneumatic bearing members 43 are disposed between the

base 8 and a heat-insulating plate 42 secured to the

bottom of the vessel 1.

Each pneumatic bearing member 43 is made of about

mm thick rubber shell. In a preferred embodiment of such

bearing member, .the.shell consists of three different rubber

421.663 layers; namely, an outer ruber layer with high resistances to aging, bending, and fatigie; an interrediate layer which withstands a high internal pressure of the bearing member; and an inner layer with a high airtightness.

The pneumatic bearing member 43 of the aforesaid

construction, for instance, can bear an internal pressure 2 of about 20 Kg/cm or can withstand a load of 10 tons or

more per pneumatic member.

A toroidal air passage 4 having substantially

the same construction as that of the embodiment of Figs. 1

to 4, can be used in this embodiment with three injectors

3, which can be secured to the vessel 1 by holders 33

through hinges 32, as shown in Fig. 6.

The translation of the vessel 1, by means of

the agitator 2, eliminates uneven distribution of the

load, because the translation intends to achieve an

even distribution of the starting materials 36, 37 and the homogeneous mixing of the molten material in the

vessel 1. In short, the mechanical load to the frame-

work 5 and different support cylinders 7 is well balanced,

so that-smooth translation of the vessel 1 can be ensured.

For the removal of the molten calcium carbide

thus formed in the vessel 1, various forms of outlet can

be provided in the vessel 1. For instance, an opening of

suitable diameter can be bored through the side wall of

the vessel in the proximi ty-of its bottom, in such a

manner that the opening may hold a plug inserted therein

during the process of making the calcium carbide. Upon

completion of the desired process for-making the molten

calcium carbide, the plug thus held may be remoVed.by

42L663

.i the ou d 7 1 1 /71 ide .2 h by, the molten calcium c.rbi.de can b, delivered i:o a suitable container, such as a ladle ready for transportacion of the product. The details of such outlet are well known to those skilled in the art, and hence, no further description will be made here.

The invention will nolw be described in further detail, by referring to Examples.

Examole 1:

A starting material, which consisted of 300 Kg of lime stone, with a composition of Table 1 and 210 Kg of coke with a composition of Table 2, was placed in a reaction vessel of Fig. 1.

Table 1

Composition of lime stone

Ingredient CaCO 3 MgCO 3 SiO 2 Fe20 3

Percentage 97.90 0.60 0.35 1.15

Talyle 2 Composition of coke

Ingredient Fixed Ash Volatile t carbon content matter Sulfur

Percentage 87.75 10.63 0.94 0.58

The injector 3 was adjusted so as to deliver a fuel-gas-oxygen mixture with an oxygen partial pressure of about 3 Kg/cm 2 and an acetylene partial pressure of about.

421.663

0.4 Kg/cm 2 27.31 171 The surface of the central portion of the starting material aas heated by the flame of the fuel-gas-

oxygen mixture, until it became white-hot.

While maintaining the combustion of the fuel- gas-oxygen mixture, compressed air is delivered to the air passage 4 to form the air curtain 31 along the inner surface of the side wall of the vessel 1, and at the same time, the driving motor 19 was started to translate the vessel I for agitation of the material.

Thus, incomplete combustion of the lime stone and coke was caused, which produced carbon monoxide gas. At this moment, the composition of the fuel-gas-

oxygen mixture was readjusted to an oxygen partial pressure of about 5 Kg/cm 2 and an acetylene partial

pressure of about 1 Kg/cm 2 for raising the temperature of the flame 38. Simultaneously, an oxygen curtain 39- is delivered from the oxygen curtain nozzles 28. Accordingly, the temperature in the vessel 1 increased to 0 about 2,500 C to 3,5000C, so that the material consisting

of the lime stone and the coke was melted and agitated,

until homogeneous calcium carbide is formed in molten

state. When the temperature of the molten substance in the vessel 1 reached at about 2,000 0 C, the delivery

of the fuel-gas-oxygen mixture, the oxygen curtain, and the air curtain was ceased by blocking the entire injector 3 and Vhe air passage 4. Then, the translation of the vessel 1 was also ceased.

The composition of the product thus obtained was

analyzed. The results are shown in Table 3.

421.663

27.31a Table 3

Example 2:

A starting material, which consisted of 200 Kg of

carbide residuum (slaked lime) and 200 Kg of anthracite, as

shown in Tables 4 and 5, was thoroughly mixed and prepared

in the form of briquette. After dryi'ng at room temperature,

the briquette material was placed in the reaction vessel 1,

which was used in Example 1.

Table 4

Comoosition of carbide residuum (slaked lime)

Table

Composition of anthracite

The same fuel-gas-oxygen mixture as Example 1

was used for producing calcium carbide through the

same process as Example 1. The composition of calcium

421.663

27.31 /71 carbide thus obtained is shown in Table 6.

Table 6

Ingredient CaC 2 CaO caS !0O A Z2 0 3 Fe20 3 C r A3 Percentage 86 7 1.5 G <0 O& 9 1.2

Example 3:

A starting material, which consisted of 300 Kg of quick lime with a composition of Table 7 and 210 Kg of coke

with the composition of Table 2, was placed in the vessel 1

of Fig. 1.

Table 7

Composition of quick lime

A fuel-gas-oxygen mixture, including heavy oil as shown in Table 8, was burned and its flame is directed to

the material in the vessel 1 by means of the injector 3.

Table 8 Composition and properties of heavy oil

I I Composition(%) Composition) Specific Flashing Baumd Residual Water gravity point degree- carbon C H S 02+N

0.9.4 111 0°C 16-24 5.7% 0.4% 85.28 11.34 1.61 1.67

After the material consisting of the quick lime and the coke was melted, an air curtain 31 was formed

421.6,63 frrin the air paPsage 4, while maintaining the flame 38 of th.: afor'esad fuel-.-.-o-ygen mixture. At the same ti. e, the driving motor 19 ,ras started to agitate the material by translating the vessel 1. Then, the temper- ature of the flame 38 was raised by readjusting the fuel/oxygen ratio of the fuel-gas-oxygen mixture, and the oxygen .curtain 39 was injected through the oxygen curtain nozzles 28.

When the temperature of the substance in 0 the vessel 1 reached at about 2,00 the delivery of

the fuel-gas-oxygen mixture, the oxygen curtain, and

the air .curtain was ceased by blocking the entire

injector 3 and the air passage 4. Then, the translation

of the vessel 1 was ceased.

The composition of the product thus obtained

was analyzed. The results are shown in Table 9.

Table 9

Ingredient CaC 2 CaO CaS Si02 AL2 0 3 Fe 2 03 C

Percentage 80 12 1.7 9-7 1.:

Salient features of the present invention are as

follows.

The melting and the chemical reaction of the

starting material, consisting of calcium material

and carbon material, are simultaneously effected

in one reaction vessel. Whereby, the desired

calcium carbide can be formed quickly through a

simple process with a high heat efficiency.

421.6 63

27 311/71 The quick chemical reaction of the starting

materials and the homogoen.ity of the carbide product

can be ensured by the simultaneous heating with a

gaseous fuel and agitation by the translation of

the vessel.

The fuel cost is greatly reduced, by burning

carbon monoxide gas, which is generated by the

reaction between the molten calcium material and

the molten carbon material, by using an oxygen

curtain in the vessel. The heat energy generated

by such combustion of the carbon monoxide is

effectively used for heating the starting

material.

The method and the device of the present invention can be used effectively, regardless of the desired amount of calcium carbide. In other

words, the method and the device of the present

invention can be advantageously applied to the

production of only a small amount or a large amount

of calcium carbide.

(51 The device of the present invention can be

manufactured at a cost which is considerably lower

than that of an electric furnace.

4 2 16 6 3

Claims (1)

1. 2 7. 31 Claims dcfi.ing the i-n-.-e(ntion are as follows:-

   1. A method for naking calcium carbide comprising

   *-steps of placing a cal-ciuminaterial and a carJbron imaterial in

   a translatable vessel, directing the flame of a fuel-gas-

   oxygen mixture to the materials from above, said fuel-gas

   being a hydrocarbon, until the top portion of the materials

   becomes white-hot, forming a heat-insulating air curtain

   along the inner surface of side wall of the vessel,

   translating the vessel along a horizontal closed path

   while maintaining the flame of the fuel-gas-oxygen

   mixture as directed to the materials, whereby the calcium)

   material and the rar-bonnaterial are heated at 2,5000°C

   to 3,50000 and melted and reacted to form calcium carbide. 2. A method according to claim 1 and further

   comprising a step of forming an oxygen curtain around the

   flame of the fuel-gas-oxygen mixture when the vessel is

   translated, whereby carbon monoxide gas. generated by the

   reaction of the calcium material and the eafr) material is

   burned by the oxygen curtain for generating reaction heat

   which is also applied to the material. 3. A method according to claim 1, wherein the

   calcium material consists of at least one ingredient selected

   from the group consisting of lime stone, slaked lime, and

   quick lime.

   4. A method according to claim 1, wherein the

   vessel is translated along a circular path.

   A method according to claim 1,.wherein the

   vessel is translated along an elliptic path.

   421.663

   27. 311 7 6. A device for making calcium carbide, comprising

   a base; a vessel receiving starting material containing

   calcium and carbon; a framr.ework integrally holding said

   vessel while being movably supported by said base; a

   continuously cooled vertical injector means being centrally

   disposed directly above said vessel and mixing separately

   delivered fuel-gas and oxygen at the lower end of the

   injector means, which injector means burns the fuel-

   gas-oxygen mixture as being formed so as to direct a

   flame of the mixture into the vessel; a toroidal air

   passage disposed along the upper edge of a circular

   side wall of the vessel,- said annular air passage having

   an annular nozzle so disposed as to inject a heat-insulating

   air curtain along the inner surface of side wall of

   the vessel; a driving means secured to the base; and

   a transmission means being operatively connected to

   the driving means and the framework for translating

   the framework together with the vessel along a horizontal

   closed path about an axis which is offset from the axis

   of the vessel, whereby the starting material in the

   vessel is simultaneously heated by the flame and agitated

   by the translation of the vessel.

   7. A device according to claim 6, wherein

   the vertical injector means includes a passage of oxygen

   and a plurality of oxygen curtain nozzles disposed along

   outer periphery of the lower end of the vertical nozzle,

   whereby an oxygen curtain is formed around the flame

   of the fuel-gas-oxygen mixture, so as to burn carbon

   monoxide gas generated by chemical reaction of the starting

   material.

   421t663

   27.311 71 8. A device according to claim 6, wherein said

   c1f:Jed path. Is circular.

   9. A devico according to claima 6, wherein said closed path is elliptic.

   A device according to claim 6, wherein

   the injector means consists of one vertical injector

   disposed substantially along the vertical axis of the

   vessel.

   11. A device according to claim 6, wherein

   the injector means consists of a plurality of vertical

   injectors disposed at corners of a horizontal equilateral polygon having a center lying substantially on the vertical

   axis of the vessel.

   12. A device according to clalm 10, wherein

   the injector means includes an oxygen passage surrounding

   said one injector and a plurality of oxygen, curtain

   nozzles disposed at the lower end of the oxygen passage.

   13. A device according to claim 11, wherein

   the injector means includes a triangular oxygen passage

   surrounding the three injectors and a plurality-of oxygen curtain-nozzles disposed at the bottom of the triangular

   oxygen passage.

   Dated this lst day of April, 1971.

   RYOSUKE ENYA By his Patent Attorneys DIVIES COLLISON

   421.663

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