Energy efficient natural gas additive and its applications

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention relates to metal cutting and more particularly to an energy efficient natural gas additive and its applications.

2. Description of Related Art

With the rapid development of China's industry, the demand for gas for cutting metal is growing. Currently, oxygen and acetylene are widely used in oxy-fuel cutting. For torch with acetylene as heating source, it has the benefits of high flame temperature and significant thermal processing effect. Thus, it is widely used in metal cutting, metal welding, deformation correction, etc. However, acetylene is disadvantageous due to poor security, high energy consumption, high price, environmental pollution, etc. In recent years, metal cutting industry is looking for alternatives such as propane, natural gas, LPG (liquefied petroleum gas), etc. Natural gas has features of high explosion limit, easy to propagate after leaking and is safer than propane and LPG. Natural gas can be safely used in a closed room in shipbuilding industry and has a lower price than propane. However, natural gas for cutting metal has disadvantages of long time to warm for piercing, slow cutting speed, low flame temperature, poor performance, and high energy consumption. It is often that additives are added to natural gas. However, most additives are corrosive and these additives are hydrogen peroxide, potassium permanganate, water, potassium hydroxide, hydrofluoric acid, perchloric acid, and hydrochloric acid. In long-term use, it will corrode cylinders, pipe walls and thus there is a great security risk. Some additives are viscous liquid, gum, or solid such as nano-alumina, iron oxide nanoparticles, naphthenate (manganese, cerium, cobalt, zirconium, copper,

Lanthanum, etc.), alkyl sulfonate, methenamine and Tween-80, etc. They cannot be completely dissolved in natural gas. Gas with liquid may damage rubber membranes of pressure reduction valves in pipes. Thus, additives containing viscous liquid or gum that is insoluble in liquid are not appropriate for long-term use. Ferrocene is also used as additive. Ferrocene is a solid. Ferrocene is required to dissolve in solvent prior to be used as additive. This additive is added to natural gas pipes and ferrocene becomes solid particles floating in natural gas after a period of time. The solid ferrocene particles may clog a torch nozpreferred embodimente, make cutting torch instable, and even cut off the torch. Further, conventional additives have poor performance. After adding to natural gas, the generated torch only reaches propane flame temperature (≦2700° C.) and cannot reach acetylene flame temperature (3100° C.). Thus, it is disadvantageous in many applications due to high energy consumption.

SUMMARY OF THE INVENTION

It is therefore one object of the invention to provide an energy efficient natural gas additive which is non-corrosive, can be completely dissolved in natural gas, and is a good synergistic to achieve energy saving and increase safety.

Another object of the invention is to provide an energy efficient natural gas additive which can be used in metal cutting.

Still another object of the invention is to provide an energy efficient natural gas additive which can be used in heating.

In one aspect of the invention, there is provided a natural gas additive comprising 10-80 wt % C₁-C₉alcohol, and 20-90 wt % C₆-C₁₁hydrocarbon.

Preferably, the natural gas additive comprises 30-60 wt % C₁-C₉alcohol, and 30-70 wt % C₆-C₁₁hydrocarbon.

Preferably, the natural gas additive comprises 45-50 wt % C₁-C₉alcohol, and 40-60 wt % C₆-C₁₁hydrocarbon.

Preferably, the alcohol is one of methanol, ethanol, isopropanol, C₄-C₉high alcohol, and a combination thereof; and the C₆-C₁₁hydrocarbon is one of toluene, xylene, trimethylbenzene, and a combination thereof.

Preferably, the natural gas additive comprises 70 wt % methanol, 20 wt % xylene, 5 wt % high alcohol, and 5 wt % C₉-C₁₁hydrocarbon.

Preferably, the natural gas additive comprises 85 wt % n-hexane, 5 wt % ethanol, 5 wt % isopropanol, and 5 wt % C₉-C₁₁hydrocarbon.

By utilizing the invention the following advantages are obtained:

In accordance with GB/T5096, the natural gas additive of the invention has copper corrosion grade I after being tested. This means that the natural gas additive does not corrode steel and can be used for a long time. The additive of the invention can be added to the pipes for conveying natural gas and natural gas cylinders, and can be added to pipes for conveying liquefied natural gas which is used for cutting or welding.

The additive of the invention has no solid particles in room temperature and can be dissolved in natural gas. It does not damage rubber membranes of pressure reduction valves in pipes. It is stable in nature.

The natural gas additive of the invention can increase flame temperature to 3150-3450° C. in cutting operation. It greatly improves the performance. Its preheat piercing time is short, its cutting speed is quick, and its uses are wide.

The natural gas additive of the invention can be widely used for cutting steel plate such as Q235B, D36, AH32, Q345B, or Q235A, and steel plates for shipbuilding. It can be safely used in a closed room in shipbuilding industry and is safer than propane and liquefied gas.

The natural gas additive of the invention can is cost effective. It can save energy. 1 ton of the natural gas additive of the invention is equivalent to about at least 2 ton of the conventional propane. It can save at least 50% fuel in comparison with the conventional propane.

The above and other objects, features and advantages of the invention will become apparent from the following detailed description taken with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a table of comparing conventional propane with natural gas additive of a first preferred embodiment of the invention in terms of cutting length, cutting speed, consumed gas, consumed oxygen, and consumed gas per meter cutting;

FIG. 2 is a table of comparing conventional liquefied gas with natural gas additive of a second preferred embodiment of the invention in terms of cutting length, cutting speed, consumed gas, consumed oxygen, and consumed gas per meter cutting;

FIG. 3 is a table of comparing another conventional propane with natural gas additive of a third preferred embodiment of the invention in terms of cutting length, cutting speed, consumed gas, consumed oxygen, and consumed gas per meter cutting;

FIG. 4 is a table of comparing further conventional propane with natural gas additive of a fourth preferred embodiment of the invention in terms of cutting length, cutting speed, consumed gas, consumed oxygen, and consumed gas per meter cutting;

FIG. 5 is a table of comparing conventional natural gas with natural gas additive of a fifth preferred embodiment of the invention in terms of cutting length, cutting speed, consumed gas, and consumed gas per meter cutting;

FIG. 6 is a table of comparing another conventional natural gas with natural gas additive of a sixth preferred embodiment of the invention in terms of cutting length, cutting speed, consumed gas, and consumed gas per meter cutting;

FIG. 7 is a table of comparing further conventional natural gas with natural gas additive of a seventh preferred embodiment of the invention in terms of cutting length, cutting speed, consumed gas, consumed oxygen, and consumed gas per meter cutting;

FIG. 8 is a table of comparing conventional propane-oxygen flame method and acetylene-oxygen flame method with the natural gas additive of the second preferred embodiment of the invention-oxygen flame method and the natural gas additive of the seventh preferred embodiment of the invention-oxygen flame method in terms of preheat piercing time; and

FIG. 9 is a table of comparing conventional pure natural gas-oxygen flame, propane-oxygen flame, and acetylene-oxygen flame with the natural gas additive of the second preferred embodiment of the invention-oxygen flame and the natural gas additive of the seventh preferred embodiment of the invention-oxygen flame in terms of flame temperature.

DETAILED DESCRIPTION OF THE INVENTION

Referring to FIG. 1, an energy efficient natural gas additive in accordance with a first preferred embodiment of the invention is discussed in detail below. The energy efficient natural gas additive comprises 20 wt (weight) % methanol, 20 wt % ethanol, and 30 wt % toluene, and 30 wt % xylene.