EP2209877A2

EP2209877A2 - Use of liquefied-gas compositions

Info

Publication number: EP2209877A2
Application number: EP08868280A
Authority: EP
Inventors: François BOLLON; Pierre Schmelzle; Pascal Manuelli
Original assignee: Total Raffinage Marketing SA
Current assignee: Total Marketing Services SA
Priority date: 2007-10-11
Filing date: 2008-10-09
Publication date: 2010-07-28
Also published as: FR2922217B1; MY149874A; US20100281764A1; CA2702434A1; WO2009083668A3; US8388705B2; WO2009083668A2; FR2922217A1; CN101827919B; JP2011500879A; CN101827919A; KR20100085973A; ZA201003156B; MX2010003924A; TN2010000153A1

Abstract

Use of a liquefied-gas composition for domestic use, comprising dimethyl ether or DME as a mixture with at least one hydrocarbon having 3 carbon atoms and at least one hydrocarbon having 4 carbon atoms in which the gas mixture released after storage contains a concentration set at a value of at most 40% by weight of DME.

Description

USE OF LIQUEFIED GAS COMPOSITIONS

The present invention relates to the use of liquefied gases and liquefied gas compositions for domestic use.

For this domestic application it is necessary to ensure a gas mixture composition capable of burning under the conditions of wealth imposed by the burner is a boiler or a stove for the housekeeper unsuspecting.

As the amount of fossil fuels decreases and is likely to fail in the long term, there is a need to find compounds that can replace these fossil fuels. However, the development of new sources of gaseous fuels and therefore replacement compositions for fossil liquefied gases implies that these new sources do not modify the behavior of liquefied gas compositions in a major way and that these compositions remain directly usable in existing installations. Thus, these new compositions must be storage stable as the existing compositions and especially be able to burn continuously, for domestic use gas sold in bottles and intended for use with conventional burners or any other type of burners, for the supply of heating installations.

International application WO 99/00466 discloses an alternative fuel for internal combustion engines, consisting of a mixture of several miscible fuels, at least one having a high octane number and at least one having a subscript. high cetane. One of these alternative fuels is composed of a liquefied mixture of at least 2 gases, one being self-inflammable by compression, the other being good oxidizer. According to one embodiment, this fuel consists of a mixture of liquefied petroleum gas (LPG), that is to say a mixture of hydrocarbons containing at most 4 carbon atoms, and of dimethyl ether (DME) with high cetane number. The use of such a fuel makes it possible to limit the emission of particles by incomplete combustion and the polluting emissions compared with conventional fuels.

European Patent EP 928,326 describes the use in a dry combustion chamber with low NO _x production of a fuel composition consisting of a mixture of three components: 15 to 93% by weight of dimethyl ether, 85% by weight of at least one alcohol and not more than 50% by weight of at least one component selected from the group consisting of water and C1 to C6 alkanes. According to a particular embodiment, the third component is selected from water, methane, propane and liquefied petroleum gas. This combustion chamber is intended for feeding a turbine for the production of energy. US Pat. No. 6,202,601 describes a method for introducing two gaseous fuels into a cylinder of a combustion engine, one being the main fuel and the other the pilot fuel being able to self-ignite more easily than the main fuel. . The main fuel is selected from natural gas, liquefied petroleum gas, biogas, landfill gas and hydrogen gas and the pilot fuel is dimethyl ether. According to a particular embodiment of the method, the main fuel and the pilot fuel are introduced separately into the engine, the main fuel in a first stage, the pilot fuel in a second stage, these stages corresponding to different modes of charging the engine. Japanese Patent Application JP 60086195 discloses a gaseous fuel composition obtained by incorporating dimethyl ether (DME) into a mixture of alkane and alkylene hydrocarbons comprising 3 and 4 carbon atoms, at a rate of 5-30 parts by weight of DME in 100 parts by weight of hydrocarbons: this mixture has good storage stability and good combustion properties. According to a particular mode, the 2 components after being respectively liquefied, are mixed before being introduced into the gas bottle. The gaseous composition will comprise propane, n-butane or i-butane but preferably propane alone with dimethyl ether or diethyl ether. This latter mixture has in particular a better storage stability and improved combustion characteristics. It is even stated that this mixture is uniform and can burn continuously, without interruption which promotes its use as fuel for businesses or for domestic applications.

It has now been found, which is the object of the present invention, that liquefied gases comprising dimethyl ether or DME mixed with at least one hydrocarbon compound containing 3 carbon atoms and at least one hydrocarbon compound containing 4 carbon atoms. allowed to improve the stability of the storage while maintaining the combustion characteristics close to those of a LPG or gas in liquid phase. Indeed, contrary to what has been described in Japanese Patent JP 60086195 the DME can not be used alone with propane because propane is consumed first and when it runs out, the DME becomes the majority and the flame s 'off. Only with butane, DME vaporizes first, ignition and flame stability become problematic. In addition, to have a regular combustion, it is preferable not to exceed the maximum concentration of 40% of DME in the gas so that the combustion in the presence of air is complete and regular. However, if adjustable air burners were available for domestic use, an optimization of the parameters could allow to incorporate more DME up to 50 or 60% by weight in the evaporated phase. The subject of the present invention is therefore the use of a composition of storable liquefied gases comprising dimethyl ether or DME mixed with a hydrocarbon mixture comprising at least one hydrocarbon containing 3 carbon atoms or propane and at least one hydrocarbon having 4 carbon atoms. carbon or butane, in which the gaseous mixture released at the outlet of the storage contains a constant concentration, set at a value of at most 50% by weight of DME until more than 50% by weight of the stored composition is released.

Thus, such compositions may be substituted for fossil liquefied gases currently available commercially for domestic use in all types of existing burner, or even for a motor use combustion remaining constant and stable.

Preferably, in the use according to the invention, the content of DME in the gaseous mixture released is set at a value ranging from 5 to 30% by weight.

Preferably, in the use according to the invention, the concentration of the DME is kept constant until more than 60% by weight of the stored gaseous mixture is released.

Preferably, in the use according to the invention, the initial gaseous mixture is composed of 10 to 30% by weight of DME, 20 to 50% of propane and 50 to 20% of butane. Preferably, in the use according to the invention, the liquefied gas composition has a DME / butane ratio of at most 7 in the initial liquid mixture.

Preferably, in the use according to the invention, the liquefied gas composition has a DME / propane ratio of at most 6 in the initial liquid mixture. Preferably, in the use according to the invention, the liquefied gas composition has DME / propane and DME / butane ratios which vary from 0.5 to 2.

Preferably, in the use according to the invention, the initial liquid mixture is composed of 5 to 40% by weight of DME, 5 to 91% of propane and 90 to 4% of butane. Preferably, in the use according to the invention, the liquefied gas composition is obtained from liquefied gases of the DME, butane and propane type.

Preferably, the use according to the invention of the composition of liquefied gases is intended for the supply of apparatus for domestic use, including boiler, stove and heater operating by combustion in the presence of air regardless of the burner used.

Preferably, the liquefied gas composition is stored in a closed chamber under pressure, of the bottle or tank type. By hydrocarbons with 3 carbon atoms is meant normal propane and isopropane hereinafter propane. By hydrocarbons with 4 carbon atoms is meant normal butane and isobutane, hereinafter butane.

By keeping the concentration of the DME constant in the gas mixture at the outlet of the storage, in the preferred mode of the invention, it is intended to ensure the maintenance of this concentration until more than 60% by weight of the gaseous mixture is consumed.

The function of propane is to ensure the start of combustion and ensure the stability thereof, it usually burning preferably before the DME and butane. The function of the butane burning after the DME is to ensure the continuous evaporation of the DME until it is completely removed from the storage, butane ensuring the maintenance of the flame.

Of course, the liquefied gas according to the invention may contain other components such as by-products of the synthesis of DME which are water and methanol. Thus, by "commercial" DME is meant a product containing at least 95% of DME.

By "commercial" propane is meant a mixture of hydrocarbons composed in the proportion of about 90% of propane, propene and for the surplus of ethane, ethylene, butanes and butenes. By "commercial" butane is meant a mixture of hydrocarbons composed mainly of butanes and butenes and containing less than 19% by volume of propane and propene.

In order to obtain a constant concentration of DME in the gaseous mixture, and to maintain a good combustion stability as well as a good calorific value of the assembly, it is necessary to adjust the propane / DME / propane and

DME / butane in the gas mixture corresponding to liquefied gas mixtures in the precise storage capacity. Preferably, DME / butane ratios of at most 7 and DME / propane ratios of at most 6 in the initial liquid mixture will be selected. Preferably, the DME / butane and DME / propane ratios will vary from 0.5 to 2.

In a preferred embodiment of the invention the gas mixture introduced into the storage is composed of 5 to 40% by weight of DME, 5 to 91% by weight of propane and 4 to 90% by weight of butane. Preferably, it is composed of 10 to 30% by weight of DME, 20 to 50% by weight of propane and 50 to 20% by weight of butane.

An advantage of the liquid liquefied gas compositions used according to the invention is their stability during storage. Measurements made on different proportions of mixtures for a period of 52 days showed no evolution of the compositions.

The liquefied gases used according to the invention can be stored according to known methods, for example in bottles, carboys, containers, tanks or tanks intended for the storage of gases and / or liquids under pressure. The filling is done according to the usual methods.

According to a preferred embodiment, the liquefied gases and the compositions described above are used for the supply of apparatus for domestic use, in particular for a boiler, a cooking stove and a heating appliance operating by combustion in the presence of air, whatever may be the case. the burner used. It is also possible to envisage the use of the liquefied gas and the compositions described above for the supply of internal combustion engines, in particular vehicles using onboard liquefied gas storage.

The following examples illustrate the present invention.

Example 1

Five liquefied gas compositions containing DME were tested and are described in Table 1 below.

They were prepared in 13 kg domestic gas cylinders by simply weighing the quantities by weight of each of the products introduced and then analyzed at the initial time by connecting the regulator of the bottle with a gas chromatograph to measure the respective concentrations. in DME, butane and propane either in the liquid phase, the bottle being arranged upside down, or in the gaseous phase, the bottle being arranged upside down.

The evolution of liquid compositions under storage conditions without gas sampling was analyzed. The results are summarized in Table 2 below

Table 2

The results show that no significant change in the composition of the liquid phase could be observed under the storage conditions, see also Figure I) - Example 2

This example concerns the evolution of the DME composition in the gaseous compositions during use.

Butane high rate compositions

A / Release of the mixture E3. Gas release rate: 0.9kg / h. Composition of the gas phase (Figure 2)

Table 3: composition of the gas phase E3 Composition of the liquid phase (Figure 3)

Table 4: composition of the liquid phase E3 B / Release of the mixture E4. Gas release rate: 0.9kg / h. Composition of the gas phase (Figure 4)

Table 5: composition of the gas phase E4

Composition of the liquid phase (Figure 5)

Table 6: composition of the liquid phase E4 Compositions with high rate of propane

A / Release mixture El. Gas release rate: 1, 2kg / h and 0.6kg / h for the last 2 kg. Composition of the gas phase (Figure 6)

Table 7: composition of the El gas phase Composition of the liquid phase (Figure 7)

Table 8: composition of the liquid phase El

B / Release of the mixture E2. Gas release rate: 1, 2 kg / h and 0.6 kg / h for the last 2 kg Composition of the gas phase (Figure 8)

Table 9: composition of the gas phase E2 Composition of the liquid phase (Figure 9)

Table 10: composition of the liquid phase E2 Propane and butane average rate compositions

These are compositions like E5 corresponding to Figure 10. Composition of the gas phase:

Table 11: composition of the gas phase E2

Composition of the liquid phase:

Table 12: composition of the liquid phase E2 * when 12 kg of gas were consumed. Analysis of the results Whatever the initial compositions of these different mixtures, during the release of the gas, very different evolutions of the compositions of the two phases are noted. In the best case of the invention, E5, there is first a decrease in the propane concentration, then that of the DME and finally an increase in that of butane. However, when it is desired to maintain a concentration of DME in the gaseous mixture at the bottle outlet of less than 40% by weight, it is immediately apparent that some of the butane-rich compositions such as E3 do not make it possible to respect this constraint ( see Table 3 where the EMR is more than 50% present in the gas initially and whose concentration decreases very slowly in the mixture (see Figure 2) and which contains little propane about 4.8% by weight in the initial mixture). It is already necessary to have E4 type mixtures, for this constraint to be respected, in which the concentration of propane is about 6% by weight. To achieve this same constraint of the DME in the gas whether in initial mixture or in final mixture, it is necessary in propane-rich mixtures such as El, to introduce a minimum of butane in the gas mixture. At the butane content present in El of less than 4% by weight in the liquid, the gaseous mixture is enriched at the end of evaporation by up to 60% of DME, which is not favorable to the safety of the combustion. On the other hand, with a butane content of more than 4% in E2, the gas phase contains less than 40% by weight of DME.

Claims

1. Use of a composition of storable liquefied gases comprising dimethyl ether or DME in admixture with a hydrocarbon mixture comprising at least one hydrocarbon with 3 carbon atoms or propane and at least one hydrocarbon with 4 carbon atoms or butane, in which the gaseous mixture released at the outlet of the storage contains a constant concentration, set at a value of at most 50% by weight of DME until more than 50% by weight of the stored composition is released.

2. Use according to claim 1, wherein the content of DME in the gaseous mixture released is set at a value ranging from 5 to 30% by weight.

3. Use of a liquefied gas composition according to one of claims 1 to 2 wherein the concentration of the DME is kept constant until more than 60% by weight of the stored gaseous mixture is released.

4. Use according to one of claims 1 to 3 wherein the initial gas mixture is composed of 10 to 30% by weight of DME, 20 to 50% propane and

50 to 20% butane.

5. Use according to one of claims 1 to 4 wherein the liquefied gas composition has a DME / butane ratio of at most 7 in the initial liquid mixture.

6. Use according to one of claims 1 to 5 wherein the liquefied gas composition has a DME / propane ratio of at most 6 in the initial liquid mixture.

7. Use according to one of claims 1 to 6 wherein the liquefied gas composition has DME / propane and DME / butane ratios which range from 0.5 to 2.

8. Use according to one of claims 1 to 7 wherein the initial liquid mixture is composed of 5 to 40% by weight of DME, 5 to 91% propane and 90 to 4% butane.

9. Use according to one of claims 1 to 8 wherein the liquefied gas composition is obtained from liquefied gases of DME type, butane, commercial propane.

10. Use of a liquefied gas composition according to one of claims 1 to 9 for the supply of equipment for domestic use, including boiler, stove and furnace operating by combustion in the presence of air regardless of the burner used.

11. Use according to one of claims 1 to 9 wherein the liquefied gas composition is stored in a closed chamber under pressure, bottle type or tank type.