JPS59219391A - Fuel gas for hot processing of metal such as fusion cutting and welding - Google Patents

Abstract

PURPOSE:To provide a fuel gas which has a high flame temp. and is excellent in flame concn., low cost and suitable for hot processing of metal, such as fusion cutting or welding, obtained by mixing butadiene with at least one 1-4C hydrocarbon in a specified vol. ratio. CONSTITUTION:The fuel gas is prepd. by mixing 60-100vol% butadiene with 40-0vol% one or more 1-4C hydrocarbons selected from among acetylene, methylacetylene, ethylene, propylene, LPG (propane, butane and butene) and LNG (methane). A fuel gas which is lighter than air is obtained when 40- 100vol% butadiene is mixed with 60-0vol% hydrogen. Although butadiene and its blended with other gases have an advantage in that they can be liquefied for storage in a cylinder, butadiene has thermal polymerizability and so a polymerization inhibitor (e.g. hydroquinone) must be added.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a fuel gas which has a high flame temperature and flame concentration, and therefore has excellent performance in metal thermal processing applications such as fusing, welding, scarfing, and gagging, and is also economically advantageous. The purpose is to provide.

Traditionally, acetylene has a high flame temperature and flame concentration, and therefore has excellent overall performance in metal heat processing such as fusing, welding, scarfing, and gagging, followed by methylacetylene and ethylene. Met. On the other hand, the economic efficiency of metal heat processing is judged comprehensively from the unit price of the gas itself, the amount of oxygen consumed, and the metal heat processing speed, but acetylene, ethylene, etc. are not cheap in unit price and have low oxygen consumption. These gases do not have the advantage of high processing speed, and are no longer economically advantageous.

For this reason, gases such as LPG (propane, butane), fluoropylene, LNG (methane), etc., which are cheaper in unit price, have come to be used for cutting purposes because they have inferior performance. Due to the above situation, it is no exaggeration to say that the current fuel gas with both pressure-thermal processing performance and economical efficiency cannot be obtained.

Therefore, various studies were conducted to obtain a fuel gas that is cheaper than acetylene and ethylene and has better heat processing performance than LPG, propylene, and LNG, and as a result, it was found that gtadiene is suitable for this purpose. The inspection process will be explained below.

Regarding the flame temperature of combustion with pure oxygen, the above gases are arranged in descending order of temperature: acetylene 3,400 to Roro 00°C, ethylene 5,000°C, 8 propylene 29D []"C, LPG (propane) 2,800°
C, LNG (methane) 2700~2780″C1 Hydrogen 2
The temperature range is between 500 and 2660°C.

On the other hand, when the heat distribution per unit volume of combustion gas, that is, the flame heat generation density (under the condition of 1 atm and 15°C) is calculated for each of these gases on a total heat generation basis, acetylene 4650-
4610 Kcal/l'if, ethylene 6760 K
cal/ M”, Propyne 370 [) Kcal
/M3, LPG (propane) Rollo 80 Kcal/M
3. LNG (methane) filter T 7 D Kcal/ M3
, hydrogen filtration 050 Kcal/M” in order of 011
The order of flame temperatures matches without exception. The flame heat generation density of getadiene is calculated to be 3870 Kcal/M3, which is lower than that of acetylene or more than that of ethylene. Therefore, although the measured value of the flame temperature of getadiene in pure oxygen is not known, it can be estimated to be 6000゛''C, which is similar to that of ethinone.Acetylene and hydrogen have the best flame concentration, followed by ethylene, and propylene. , LPG (Pronokun)
, butane is considered inferior. Regarding this, in the chemical formula where these gases are completely combusted in pure oxygen, combustion i
This seems to be related to the increase/decrease in the number of moles after ff. The combustion gas expansion rate is calculated by dividing the number of moles of produced gas (i.e. CO2 and H2O) after combustion by the total number of moles of fuel gas and oxygen before combustion (
However, 1. (below θ is contraction) is arranged in descending order of magnitude as follows.

Hydrogen 0.67, Acetylene 0.857, Ethylene 1.0
1LNG (methane) 1.0, propylene 1.09, L
PG (propane) 1. +67, and butane 1.20.

In the case of getadiene, this gas expansion coefficient is 1076, indicating that it is between ethylene, LNG (methane), and propylene. Therefore, the flame concentration is strong for hydrogen, acetylene, ethylene, and LNGK, but propylene, LP
It is expected to be superior to G (propane), butane, etc.

As mentioned above, the flame temperature and flame concentration of getadiene are as follows:
Regarding the metal thermal processing performance affected by these factors, as shown in the examples below, LPG, which is currently used for hole cutting,
It has been found that the level is comparable to that of (propane).

Regarding the various elements of workability in actual metal heat l111 work, the following 5 items are based on the factors of high flame temperature and heat f with good flame concentration. Items include short preheating time, fast heat processing speed, and easy flame adjustment. In addition to these factors, it is desirable that the maximum ignition temperature of the fuel gas is as low as possible because it is easy to ignite and there is little chance of the flame blowing out. In order of lowest ignition temperature, acetylene is 305°C, propylene is 458°C, and LPG (propane) is 481°C.
1 ethylene 490"C, hydrogen 5726"C, and LNG (methane) 662"C.The lowest ignition temperature of butadiene is 1-1429"C, which is higher than acetylene but lower than propylene, so the workability is not as good as acetylene. It has been proven that this gas is superior to other fuel gases from ponds.

Regarding economic efficiency, the cost of fuel gas (gas unit price plus container cost,
This should be comprehensively judged, taking into account not only the total of filling costs and shipping costs, but also oxygen consumption and heat processing speed. First, if we talk about the cost of getadiene, the gas unit price is the same as or slightly higher than that of globylene, but the boiling point of butadiene at 1 atm is -4.4°C, which is higher than propylene and LPG ( (i.e., low vapor pressure), the total cost of container cost, filling cost, and freight (i.e., the price of getadiene as cylinder filling gas) is not much different from the price of propylene or LPG filled in a cylinder, but it is similar to the price of propylene or LPG filled in a high-pressure cylinder, It is far more reliable than acetylene etc. packed in mass-packed high-pressure cylinders.

Next, regarding oxygen consumption, Jlj of oxygen per unit weight
In order of gases with the least theoretical amount (weight unit), acetylene filter, 072, methyl acetylene filter 195, getadiene 5.253, ethylene and propylene filter, 422,
Butane 6.578, LPG (propane) 6.628, L
NG (butane) is in the order of 3.990, and butadiene follows acetylene and methylacetylene, indicating that the oxygen consumption ratio is lower than that of pond crystal gas. This fact is also experimentally shown in the examples described below for 11 units, which require a smaller amount of oxygen for preheating than LPG (propane).

Regarding the thermal processing speed of metal, especially the fusing speed, when the gas consumption part is the same, the higher the flame temperature mentioned above and the better the flame concentration, the faster it is.As shown in the examples below, LPG (
Compared to propane), getadiene has a faster cutting speed and is harder.
It can be seen that the difference is particularly noticeable in the case of a 300V groove.

As mentioned above, in terms of economic efficiency, getadiene is the cheapest conventional metal heat processing gas, LPG (propane, butane, butene), It has been shown that it is comparable to propylene.

The following describes the suitability of a simple gas with getadiene purity of 98% or more as a gas for thermal processing. Alternatively, it can also be used by adding and mixing several types of 4Q vo1% or less (that is, the getadiene content is 60vo1% or more) in principle. The effects of mixing are 1) an increase in the flame temperature of the fuel gas with a relatively calorific value of 1000 m², 2) an increase in the vapor pressure of butadiene itself, 3) a reduction in the gas specific gravity of getadiene itself, and 4) a reduction in the use of expensive high-performance gases. Cost reduction, etc.

In the case of 1), LPG (propane, propylene, butene)
, LNG (methane), propylene, city gas, and hydrogen are added and mixed, and there is a main effect of increasing the flame temperature of these gases, that is, a force 01 J-amp effect.

In case 2), butane diene has a high boiling point (-4 at 1 atm).
, 4°C), and to compensate for the fact that it is difficult to vaporize in a pressurized container (cylinder) during winter, it is necessary to
The C3 hydrocarbon gas group is useful because it dissolves well in the getadiene liquid and raises the vapor pressure at room temperature. In the case of butadiene gas, the specific gravity at room temperature is 1.87 compared to air, so if gas leaks during fusing work inside a ship or yard with poor ventilation, it will stay at the bottom of the ship or tank and cause an explosion. There is a risk of causing a disaster. In this case, getadiene has a specific gravity of 0.0.
As an exception to the above-mentioned principle, hydrogen, which is extremely lightweight at 50~
When 60 VO 1% is added and mixed in the gas phase, the specific gravity of this mixed gas is 0.97 to 0.8, which is lighter than the specific gravity of air of 1.0, making it difficult to stay at the discharge point, and the light acetylene in the pond, It can be used safely inside ship structures and tanks, as well as LNG (methane), hydrogen, and ethylene.

In the case of 4), when getadiene is added to and mixed with a fuel gas such as acetylene, which has good performance but is not cheap, the main purpose is to reduce the cost of these expensive gases. Propylene, LNG (methane)
It is known to use However, in the case of getadiene, as mentioned above, the flame temperature is higher than that of propylene, LNG (methane), etc., and the flame concentration is good, so it is originally a high-performance acetylene (in some cases, methylacetylene or ethylene).
This has the advantage of reducing costs without significantly reducing performance. The various effects of adding and mixing getadiene with a specific fuel gas have been described above, but the method of mixing and adding it is to mix and dissolve it in the getadiene liquid in a pressurized container. (propane, butane, butene), methylacetylene, etc.

Acetylene, ethylene, and LN with large fli points
In the case of G (methane), hydrogen, etc., it is preferable to add and mix it to butadiene gas in the gas phase, and either to mix it in a gas container under normal pressure or several atmospheres of pressure, or to separate pipes from separate pressurized containers. For example, a method of mixing using an ejector type instantaneous gas mixer can be appropriately selected.

Incidentally, as an example of a fuel gas for thermal processing in which getadiene is mixed with pond gas, propylene 45 to 50 vol.
, methylacetylene/getadiene 55-50 vol1%
A gas with the trade name "Super Jet" with a published composition of 2
types are known.

Butadiene in these gases is contained in the crude distillate containing methylacetylene and is mixed as a secondary component, and as in this application, it is an independent gas that is actively used to take advantage of its properties. It is basically different in that it is not a principal component. This can be understood from the following content of getadiene in both gases. Although there are no directly published values for getadiene concentrations in both of these known gases,
Regarding “Super Je Sotogas”, the specific gravity is 1.52.
Since the data is known, the butadiene gas concentration estimated from this is +6.3 vol% to 17.5 vol.
%, and the pond methyl acetylene is Uro, 7 vol.
%~ro 7.5 vo1%, remaining 5O-45 vol
% is propylene. "Hydrojet S Gas" has a specific gravity of 0.87 and a theoretical oxygen amount (in moles) of 2.
Since the data in No. 7 is publicly known, the butadiene gas concentration estimated from this is 28-10vol%, and the same concentration of methylacetylene is 17-21vo1%, propylene is 5-23vol%.
VO1%, remaining 50-45 VO1% are water brothers.

In any case, the butadiene content in both of these known commercial gases is 3 Q vo 1% or less divided by 60 vo 1% to 100 vo 1%, based on the getadiene concentration in the case of the present application.
As an exception, even in the case of weight reduction using hydrogen, the composition range is completely different from the case where the concentration of Zokudiene is 40'vo1% or more.

The above-mentioned getadiene single gas and mixed gas (in principle, getadiene 60 vol 1% or more) have a vapor pressure of only a few atmospheres to 10-odd atmospheres (room temperature to 50"C), so they cannot be used in the currently widely used lightweight LPG cylinders. However, since butadiene is inherently thermally polymerizable, it is necessary to add 100 to 50 ppnl of a polymerization inhibitor (e.g. t-butylcatechol, hydroquinone, etc.) in advance. Also, care must be taken not to heat it above 50°C.

Next, the effectiveness of the present invention as a fuel gas for metal thermal processing will be explained with reference to Examples and Comparative Examples.

Example 1 Getadiene with a purity of 98.5 vol. 1% was liquefied and filled into a cylinder, which was subjected to a fusing test and compared with commercially available LPG (propane 85%, butane 10%, butene 5%).

The fusing test was performed on a 25-thick mild steel plate (SS41) at a cutting speed of 60, 400, 450 am/min each with an I cut, and 320, 360, 400 am/min each with a 60 degree V cut.
A fusing test was conducted using an automatic cutter using a propane straight π2 for each crater. Table 1 shows the data for the minimum gas consumption of the cutting speed at which a class 1 gas cut surface according to the WES standard can be obtained, and a beautiful cut surface with a roughness R of about 25S can be obtained.

Table 1 (- Table 1 shows fusing speed or beveling ■/10 for cut
0 mm/” min, 36 D for V cut
Height of mrJmllT ~ (4: Butadiene and 1・I)
When I compared the cutting costs of G, there was no difference with just one cut. ■ Cutting G-, [Is it the power of Butadiene? L P G
Compared to the above, Butadiene requires less in both the quantity and preheating oxygen, indicating that it is more economical.

Example side Example 1: 7kudiene 6Q instead of butadiene v
O1% contains Ayachilene, Ethylene, Fluhilene, LPG
(propane, butane, butene type), LNG (metacrylic type), each using a mixed gas of 4 Clvol%, and a mixed gas of 60 vol% of hydrogen in 4Q vol% of butarenine were conducted under exactly the same conditions and procedure.

The gas consumption is listed as the lowest value that can be stably obtained according to the WES standard 1st class i■1i. In the control example, a mixed gas containing 30vol 1% or less of butadiene was used.

In Example 2, compared to Control Example 2, it was shown that the length had more butadiene, the fusing speed could be made faster, and at the same fusing speed, both gas extinguishing and preheating oxygen were less/equal. ing.

Claims (1)

[Claims] 1) Getadiene 60-100 vol% and acetylene, methylacetylene, ethylene, flopylene, LPG (
A fuel gas for metal thermal processing such as fusing and welding, which is a mixture of 40 to 1% Ovo of one or more of 01 to C4 hydrocarbons such as 7'-ropane, butane, butane), LNG (methane), etc. 2) Getadiene 40-1'00 vo1% and hydrogen'60
A fuel gas for metal thermal processing such as fusing and welding consisting of ~Q vo1%.