JPS6142592A - Mixed gas - Google Patents

Abstract

PURPOSE:A mixed gas suitable for use as a fuel gas for welding, fusion cutting, and heating, made by mixing natural gas, hydrogen gas, and acetylene gas in the specified proportions. CONSTITUTION:A mixed gas consisting of 20-70mol% natual gas (part of the hydrocarbon components may be suitably increased or decreased), 10-60mol% hydrogen gas, and 20-70mol% acetylene gas (total being 100mol%). This mixed gas has a calorific power similar to that of acetylene gas; has high safetiness because of lighter weight than air, thereby causing no back firing; and is inexpensive.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention is applicable to each gas within the range of 20 to 70 mol% of natural gas-based hydrocarbons, 10 to 60 mol% of hydrogen gas, and 20 to 70 mol% of acetylene gas. The present invention relates to a mixed gas characterized by being mixed such that the total of

<Prior Art> Conventionally, acetylene gas and LP gas have been generally used as fuel gas for this type of technology.

<Problems to be solved by the invention> However, in such conventional fuel gases, if acetylene gas is not handled carefully, it is likely to cause disasters due to backfire accidents, and furthermore, carbide, which is a raw material, is It is a consumable product, and there is a risk of decomposition and explosion when compressed, so gas alone cannot be compressed and filled into a container, so a high-pressure container is filled with a porous material and a solvent is soaked into it. Since the acetylene gas must be melted and filled before being transported and used, there are drawbacks such as high costs.

In addition, since LP gas has a higher specific gravity than air, it tends to accumulate in the event of a gas leak, and there is a danger that it will fill up inside a factory, ship, or pit and form an explosive gas mixture over a long period of time. However, they have drawbacks such as difficulty in using them depending on the purpose.

Therefore, if natural gas, which has a low gas specific gravity and is rich in safety, or a composition gas with i19 of some of its components (natural gas-based hydrocarbon) is used instead of acetylene gas, the gas specific gravity of natural gas is φ higher than that of air. Even if there is a gas leak, it diffuses more easily than acetylene gas, so there is less stagnation.It is ideal as a processing gas in narrow spaces, inside ships, and inside bits, and its explosion limit in air is twice that of acetylene gas. It is also safer than other gases because it does not reach the explosive limit unless a considerable amount of gas leaks. In addition, because it has a high ignition temperature and a slow combustion speed, it is resistant to backfire and is the safest fuel gas. Furthermore, natural gas exists in large quantities in nature and is supplied at a very low cost.

However, although natural gas has advantages in terms of low cost and safety, it has a slow combustion speed, resulting in poor flame concentration and problems in terms of work efficiency.

Means for Solving the Problems> The present invention was made to improve the problems of natural gas, and consists of three types of natural gas: hydrogen gas, which has a high combustion rate, and acetylene gas. The aim is to produce a mixed gas and improve heating power and safety.

Effect> As an experimental method, the mixing ratio of natural gas, hydrogen gas, and acetylene gas was varied, and the gas specific gravity, explosion limit, flashback resistance, and heating power were determined.

First, Table 1 shows the test results of the flashback performance of the mixed gas. The test method was to form a neutral flame with oxygen gas at a mixed gas flow rate of 60ONj2/h, and place the tip of the crater against a closing plate for 10 minutes.
0＠Press it repeatedly to see if it backfires.

If natural gas is less than 20%, flashback will occur no matter what the mixing ratio is, so Table 1 shows the case where natural gas is 20% or more.

Table 2 Mixture ratio (mol%) that does not cause flashback: The mixed gases with less than 10% hydrogen gas in Table 2 have poor flame concentration (
Difficult to use. Therefore, 10% or more of hydrogen gas must be mixed.

Therefore, the mixture ratios at which flashback does not occur and flame concentration is excellent are as shown in Table 3.

Next, to explain the heating power test method and results, the heating power was determined by preheating a 12-thick general structural steel rolled steel SS-41 with a neutral flame with oxygen gas at a mixed fuel gas flow rate of 60ON 1/h. , the time required to drill into steel material, that is, the drilling time, was expressed as an index. The shorter the drilling time, the better the heating power, so it is convenient to use the drilling time as an index of heating power for comparing results.

The tested mixture ratios were limited to those in a range where no flashback occurred, and the measurement results are shown in FIGS. 1 to 6.

Figure 1 shows the drilling time when natural gas is 20 mol%;
The figure shows natural gas at 30 mol%, Figure 3 shows natural gas at 40 mol%, Figure 4 shows natural gas at 50 mol%, Figure 5 shows natural gas at 60 mol%, and Figure 6 shows natural gas at 70 mol%. % time. From these figures, if the acetylene gas mixing ratio is less than 20%, the drilling time tends to be significantly longer, so in order to ensure heating power, the acetylene gas mixing ratio must be 20% or more.

Similar results were obtained when examining natural gases with various compositions, as well as compositions in which some of the components of natural gas were increased or decreased.

Therefore, the mixing ratio that can ensure heating power without backfire is the 4th one.
As shown in the table, the mixed gas of the present invention contains 20 to 70 mol% of natural gas-based hydrocarbons, 10 to 60 mol% of hydrogen gas, and 20 to 70 mol% of acetylene gas, and the total of each gas is 100%. It is essential that the gas be mixed so that

Since the gas specific gravity of all the mixed gases in Table 4 is significantly lighter than air, there is no problem with the mixed gases in Table 4 from the point of view of gas specific gravity.

<Example> FIG. 5 shows the gas specific gravity, explosion limit, presence or absence of flashback, and drilling time in an example of the present invention. For comparison, similar measurements were performed for 100 mol% acetylene gas and 100 mol% natural gas, and the results are shown in the table.

Mixture example Fish 1 contains 20 mol% natural gas and 60 mol% acetylene gas.
It is a mixed gas of 20 mol% of hydrogen gas and 20 mol% of hydrogen gas.

The gas specific gravity is 0.67, which is significantly lighter than acetylene gas.

Therefore, even if there is a gas leak, it will diffuse immediately without stagnation and will not cause flashback, making it significantly safer than 100 mol% acetylene gas. The drilling time was 13.2 seconds, compared to 1 for acetylene gas alone.
It takes close to 2 seconds, and the heating power can be said to be comparable to that of acetylene gas. Furthermore, it is inexpensive because it contains only 60 mol% of acetylene gas.

Mixed inverted 2 contains 30 mol% natural gas and 40 mol% acetylene gas.
It is a mixed gas with a hydrogen gas content of 30% by mole. Since the amounts of natural gas and hydrogen gas are larger than the mixed gas in No. 1, the gas specific gravity is 0.55, which is lighter than natural gas.

Therefore, even if there is a gas leak, it will quickly diffuse without stagnation, and there will be no backfire, making it an extremely safe fuel mixture, so it can be used in narrow spaces, inside ships, in pits, etc. perfect for.

The drilling time was 15.6 seconds, which is less than the 12 seconds for acetylene gas, but significantly improved from the 26 seconds for natural gas alone. Furthermore, it contains 40 mol% of acetylene gas.
It is very cheap as it only contains

Incidentally, since natural gas has various compositions, any composition can be used, and there is no problem even if the hydrocarbon components of natural gas are increased, decreased, or separated as appropriate.

As described above, the fuel gas according to the present invention is significantly lighter than air, does not cause backfire, is highly safe, has heating power close to that of acetylene gas, and is inexpensive.

In addition, the fuel gas according to the present invention can be used by mixing natural gas-based hydrocarbons, acetylene gas, and hydrogen gas in a certain ratio in the M vehicle by using a mixing device as shown in FIG. You can.

<Effects of the Invention> As detailed above, the fuel gas in the present invention can be easily mixed by using a mixing device, is lighter than air and does not cause backfire, so it is safe and inexpensive. It has features that can be used.

[Brief explanation of the drawing]

Figures 1 to 6 show natural gas-based hydrocarbons at 20° to 7
The gas specific gravity and perforation time are shown when the mixing ratio of acetylene gas and hydrogen gas is varied as 0 mol%. FIG. 7 is a simplified diagram of the gas mixing device. Applicant Koike Sanso Kogyo Co., Ltd. Taiyo Sanso Co., Ltd. Agent Patent Attorney Shukichi Nakagawa Figure 4 Figure 5 Figure 6 50403020 +00 403020100 30
20100 Figure 7

Claims (1)

[Claims] Natural gas-based hydrocarbons 20-70 mol%, hydrogen gas 10%
60 mol % and acetylene gas 20 to 70 mol % so that the total of each gas is 100 mol %.