FI91625B - Tank for environmentally harmful liquids - Google Patents

Description

5 91625 Tank for environmentally harmful liquids Behällare för miljöfarliga vätskor

The invention relates to a container for storing liquids harmful to the environment. More specifically, the invention relates to a double-jacketed container from which environmentally harmful liquids are prevented from entering the environment due to container leaks.

10 The storage of many environmentally harmful liquids in above-ground or underground storage tanks is a problem. When a tank breaks out, for example due to corrosion, the contents of the tank can leak into the environment and, for example, contaminate groundwater. Often, and especially in underground tanks, leaks are only detected after long periods of time, allowing significant amounts of harmful substances to leak out and pollute 15 the environment and groundwater.

It is known to use double-shell tanks, for example for the storage of fuels and chemicals, and in some areas other types of tanks are not permitted. It is also known to fill the space between the jackets with a mixture of ethylene glycol and water which is pressurized or subjected to hydrostatic pressure by means of an expansion tank. If the inner jacket or outer jacket ruptures, this is detected as a change in pressure or a change in the level of the liquid in the expansion tank.

However, the use of glycol is inherently harmful. When the outer casing breaks out, it gets into 25 soils where it is difficult to remove. Glycol is water-soluble and therefore spreads rapidly over a wide area, from which it is difficult and expensive to remove.

When the inner jacket bursts, water and glycol get into the liquid to be stored, which causes contamination of the contents of the tank. Even a small amount of glycol, for example in petrol, diesel, 30 light fuel oils, causes serious dirt, running and scaling problems in engines and oil burners. In addition, the glycol-water mixture causes corrosion of the tank liners. The corrosion inhibitors necessary to prevent corrosion further increase the toxicity of the mixture.

Thus, there is a need for double-jacketed tanks in which the protective liquid used does not have the above-mentioned disadvantages. The above-mentioned problems have been solved in the container according to the invention.

The invention thus relates to a container for storing environmentally harmful liquids which has at least a partial double jacket and in which the space between the jackets contains a liquid. The container according to the invention is characterized in that a liquid is used as the liquid in the space between the diapers, which has the following properties: (a) is harmless to the environment when it comes outside the container; and 10 (b) is harmless to the product held in the container itself.

The liquid used must be harmless to the environment, so that no problems of contamination and disposal arise as a result of the possible rupture of the outer casing. More desirable are liquids that decompose spontaneously as a result of natural decomposition activities, so that separate collection and destruction is not required, even in small spills.

Another requirement for the liquid used is that it does not cause harm to the liquid stored in the container in the event of a burst of the inner shell. This means that the liquid used does not interfere with the use of the product to be stored for its original purpose in reasonably small amounts. For example, in the case of gasoline or diesel, this means that the fluid used does not cause problems with engine operation in reasonable quantities.

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Fluids that meet the above requirements are certain biodegradable liquids that are naturally degradable by bacterial activity on their own. Particularly suitable are certain substances of natural origin, such as various vegetable oils and their esters. Ordinary alcohols such as methanol and ethanol are also suitable. Some synthetic esters, such as ‘biodegradable esters used as lubricants’, are also suitable.

30 The above-mentioned liquids also do not cause poisoning or contamination problems for the liquid stored in the tank.

Examples of suitable liquids for use in the container of the invention are thus

II

3 91625 Vegetable oils or vegetable oil esters, petroleum esters, alcohols and synthetic biodegradable lubricating oils. Particularly suitable are e.g. rapeseed, colza, soybean or sunflower-seed oils or their esters, and tall oil ester.

5 For example, rapeseed oil ester has a pour point of about -30 ° C, which is a low enough value for underground tanks. Rapeseed oil has a flash point above 100 ° C, so its fire class is not a problem. The inclusion of rapeseed ester in the fuel is not detrimental, but rather advantageous. For example, the smoke and particulate emissions of a diesel engine are further reduced by mixing rapeseed oil ester with diesel oil. Rapeseed oil ester also does not cause corrosion problems. The other liquids listed above have at least partially similar properties.

The container according to the invention has at least a partial double jacket. Thus, the double jacket does not have to surround the entire container, but the container may have a simple wall on those 15 parts which are not in contact with the liquid to be stored. Thus, the top of the tank may be of normal construction, but the wall below and on the sides is double.

Methods and equipment known per se can be used to detect leakage. One way to detect a leak is to maintain an overpressure in the space between the double walls. 20 The system may include an alarm when the pressure drops in the space between the walls. Another more common way is to take advantage of an expansion tank and a surface sensor.

The tank according to the invention can be applied both as an above-ground tank and as an underground tank. Particularly in the case of an underground tank, the advantages of the invention are obvious, since expensive and laborious soil cleaning is avoided and it is not necessary to build an expensive lining under and around the tank, for example a concrete trough.

The container according to the invention is suitable for the storage of all kinds of toxic and environmentally harmful liquids. Such fluids include fuels such as gasoline, diesel and fuel oil, solvents, lubricating oils, and other toxic chemicals.

Claims (7)

1. Container for storage of environmentally hazardous liquids with etmistone a partial double mantle, the space between the mantles containing liquid, characterized in that as liquid 5. the space between the mantles is used a liquid with the following properties: (a) is harmless to the environment if it is found outside the container; and (b) is harmless to the product stored in the container. 10 Container according to claim 1, characterized in that said liquid is biodegradable. Container according to claim 1 or 2, characterized in that said liquid is selected from the group of plant oils or esters of plant oil or tall oil, alcohols or synthetic biodegradable lubricating oils. Container according to claim 3, characterized in that said liquid is ripening oil, soybean oil or sunflower oil or esters thereof. Container according to any of the preceding claims, characterized in that it is equipped with means for detecting leakage in the inner and / or outer wall. Container according to any of the preceding claims, characterized in that the space between the sheaths is under pressure. 25 Use of the container according to any of the preceding claims as an undegradable or above-ground container for fuel, chemicals or solvents.