Patent Application
20240076247
The present disclosure relates to emulsion-type explosives of the water-in-oil type.
Emulsion-type explosives have become increasingly more important in the civil explosives industry. In an emulsion explosive of the water-in-oil type for the explosives industry, two immiscible phases are mixed, i.e., an (aqueous) oxidizer phase which is the discontinuous phase and an organic (oil) phase which is the continuous phase. The discontinuous phase or oxidizer phase consists of an usually supersatured solution of one or more oxidizing salts such as amongst others ammonium nitrate (AN). Other chemicals such as additives, pH-modifier, urea, etc, can also be present in the oxidizer phase. The continuous phase or organic phase consists of one or more fuels and one or more emulsifiers. The discontinuous (oxidizer) phase consists of droplets that are finely dispersed in the continuous (organic) phase. Typical examples of fuels include diesel, paraffin wax, paraffin oil, slack wax and the like. In the organic phase, an emulsifier is added, which acts at the interface between the two phases to stabilize the emulsion. Due to its organic nature, the emulsifier is included in the stoichiometry of the explosion. Due to supersaturation and the immiscibility of the two phases that are mixed, an emulsion explosive is a metastable system. The emulsion is said to “break” when the organic phase and the oxidizer phase separate and/or some oxidizer crystallizes out of the oxidizer phase.
Ammonium nitrate (AN) emulsions used for mining applications normally use a non-renewable mineral fuel, typically diesel, as the main fuel. However, there is a demand for a “greener” solution (more environmentally friendly) and a more sustainable solution in view of the raw materials used in the explosive emulsion. However, renewable oils have by nature a totally different chemistry and behavior than diesel or other non-renewable oils, which affect the viscosity and stability of the emulsion composition. Indeed, contrary to a classical emulsion in which the organic phase containing a classical, non-renewable fuel (e.g. diesel) is mixed with an aqueous ammonium nitrate solution i.e. a monosalt oxidizer phase, mixing the same oxidizer phase with the same emulsifier, and instead of diesel, a renewable oil which by its nature has a totally different chemistry and behavior than diesel, no emulsion or an unstable emulsion that will break in a short time will be formed. There thus remains a need to identify new fuel sources and formulate stable emulsion compositions based on these.
The inventors have surprisingly found that stable explosive emulsions comprising chemically processed renewable oils as fuel can be obtained by adding a suitable amount of one or more secondary salts, in particular calcium nitrate. In particular, the inventors have surprisingly found that the viscosity of the explosive emulsion could be reduced by including a HVO as defined herein in the fuel composition. In particular, stable explosive emulsions with low viscosity, and thus easily pumpable, were obtained with a fuel composition comprising hydrotreated vegetable oil (HVO) in combination with an oxidizer phase comprising ammonium nitrate and a secondary nitrate, such as calcium nitrate or sodium nitrate.
According to a first aspect of the present disclosure, an explosive emulsion composition of the water-in-oil type is disclosed, comprising
Chemically processed renewable oils are renewable oils of which the chemistry has been adapted, often to mimic the diesel characteristics, especially for engines' applications and compatibility. By replacing at least part of the normally used non-renewable oil with either a single chemically processed renewable oil or a mixture of different chemically processed renewable oils, in particular a hydrotreated vegetable oil (HVO), or a combination of one or more chemically processed renewable oils, in particular HVO, with one or more straight vegetable oils, a “greener” explosive emulsion is obtained. However, using chemically processed renewable oils destabilizes the emulsion or it hampers the emulsification process through which no emulsion is formed, particularly for mono-nitrate salts explosive emulsion compositions. Reformulating the composition of the emulsion with at least 5 wt. % of one or more secondary nitrate salts (a single secondary salt or a mix of different secondary salts), such as at least 10 wt. % of one or more secondary nitrate salts, in view of the total weight of the oxidizer phase composition added to the already present ammonium nitrate in the oxidizer phase surprisingly allows to produce stable emulsions.
In a specific embodiment of a composition according to the present disclosure, the explosive emulsion composition comprises between 85 wt. % and 95 wt. % oxidizer phase and between 5 wt. % and 15 wt. % organic phase, both in view of the total weight of the emulsion composition.
In a particular embodiment of a composition according to the present disclosure, the fuel composition consists of between 0 wt. % and 80 wt. % of one or more straight vegetable oils, more in particular between 20 wt. % and 80 wt. % of one or more straight vegetable oils, and between 20 wt. % and 100 wt. % of one or more chemically processed renewable oils, in particular HVO, more in particular between 20 and 80 wt. % of one or more chemically processed renewable oils, in particular HVO, all in view of the total weight of the fuel composition.
In a possible embodiment of a composition according to the present disclosure, the fuel consists of 100 wt. % of one or more chemically processed renewable oils, in particular HVO, in view of the total weight of the fuel composition.
In an optional embodiment of a composition according to the present disclosure, the oxidizer phase comprises between 40 wt. % and 80 wt. % of ammonium nitrate (AN) and between 5 wt. % and 50 wt. % of calcium nitrate (CN) or sodium nitrate (SN) or a mixture thereof, more in particular between 10 wt. % and 40 wt. % CN, SN or a mixture thereof or between 10 wt. % and 40 wt. % CN, all in view of the total weight of the oxidizer phase composition.
In an embodiment of a composition according to the present disclosure, the oxidizer phase comprises between 5 wt. % and 25 wt. % of water, in view of the total weight of the oxidizer phase composition.
In a possible embodiment of a composition according to the present disclosure, the emulsifier is present in an amount of between 0.5 wt. % and 5.0 wt. %, more in particular between 1.0 wt. % and 2.5 wt. %, in view of the total weight of the emulsion composition.
In a particular embodiment of a composition according to the present disclosure, the emulsifier is from a renewable source. In combination with 100 wt. % of a renewable oil in view of the total weight of the fuel composition, a fully green explosive emulsion is obtained.
In a possible embodiment of a composition according to the present disclosure, the SVO is chosen from soybean oil, palm oil, rapeseed oil, canola oil, maize oil, corn oil, sunflower oil, ricin oil, coconut oil, jojoba oil, jatropha oil or a mixture thereof.
In an embodiment of a composition according to the present disclosure, the explosive emulsion comprises
In a possible embodiment of a composition according to the present disclosure, the explosive emulsion comprises
In an embodiment of a composition according to the present disclosure, the composition has a viscosity of between 10,000 and 200,000 cP measured with a Brookfield viscometer with spindle size 7 at a frequency of 20 rpm.
The present disclosure relates to water-in-oil type emulsion explosives comprising an (aqueous) oxidizer (discontinuous) phase and an organic (continuous) phase, wherein the organic phase comprises renewable fuel oils. In general, the present disclosure provides stable, green explosive emulsions in which most or even all of the non-renewable oil in the organic phase as used in traditional explosive emulsions is replaced by one or more renewable oils and wherein the oxidizer phase generally comprises ammonium nitrate and at least one secondary nitrate salt. Advantageously, the viscosity of the explosive emulsions according to the present disclosure can be adapted to be used in different applications. The evaluation of the stability, in particular the shear stress stability, of an explosive emulsion composition is known to the skilled person and includes determining the number and size of crystal formed in the emulsion by means of a polarized light microscope analysis.
The explosive emulsion composition typically comprises between 80 wt. % and 95 wt. % of an oxidizer phase and between 5 wt. % and 20 wt. % of an organic phase, both in view of the total weight of the emulsion composition. More in particular, the explosive emulsion composition comprises between 85 wt. % and 95 wt. %, or between 90 wt. % and 95 wt. %, oxidizer phase and between 5 wt. % and 15 wt. %, or between 5 wt. % and 10 wt. % organic phase, both in view of the total weight of the emulsion composition.
The organic phase typically comprises between 12 wt. % and 50 wt. % of one emulsifier or a mixture of different emulsifiers, and between 50 wt. % and 88 wt. % of a fuel composition, both in view of the total weight of the organic phase composition. The organic phase of the explosive emulsion composition according to the present disclosure generally comprises between 1 wt. % and 8 wt. %, more in particular between 2 wt. % and 6.5 wt. %, between 2.5 wt. % and 6.5 wt. % or between 2 wt. % and 5 wt. %, even more in particular between 3.0 wt. % and 6.0 wt. %, or between 3 wt. % and 4.5 wt. % of a fuel composition, based on the total weight of the emulsion composition.
In general, the fuel composition may consist of between 5 wt. % and 100 wt. % of a single chemically processed renewable oil or a mixture of different chemically processed renewable oils, and between 0 wt. % and 95 wt. % of a single straight vegetable oil (SVO) or a mixture of different straight vegetable oils, in view of the total weight of the fuel composition. Optionally, up to 50 wt % of a single non-renewable oil or a mixture of different non-renewable oils, in particular diesel oil or white oil, in view of the total weight of the fuel composition, can be present in the fuel composition. As used herein, with one or more is meant a single oil or a mixture of different oils. It is also possible that the fuel consists of 100 wt. % of a single chemically processed renewable oil or a mixture of chemically processed renewable oils, in view of the total weight of the fuel composition. In certain embodiments, the fuel composition consists of 100 wt. % of a hydrotreated vegetable oil (HVO), in view of the total weight of the fuel composition.
By chemically processed renewable oils is meant renewable oils of which the chemistry has been changed, particularly by transesterification, hydrotreatment, hydrocracking or isomerization. Chemically processed renewable oils include bio-diesel, recycled heat-treated vegetable oil, recycled heat-treated animal fat, hydrotreated renewable oil, or a mixture of two or more of these.
Bio-fuels are any type of transportation fuel that is derived from biomass including plant or algae material or animal waste. The bio-fuels comprise bio-diesel as well as other types of chemically processed oils which have a chemistry which has been adapted to mimic the diesel characteristics, especially for engines. These oils comprise hydrotreated (also called hydrogenated) vegetable oils, recycled vegetable oils or recycled animal fats, waste from wood processing, etc. These type of oils produce lower greenhouse emissions by 40-90%, they often have higher energy per content yields than petroleum-based diesels, and better cold-flow properties to work in colder climates. There are many different suppliers of such chemically processed renewable oils.
Biodiesel is a form of diesel fuel derived from plants or animals and consisting of long-chain fatty acid esters. It is typically made by chemically reacting lipids such as animal fat (tallow), soybean oil or other vegetable oils with an alcohol, producing methyl, ethyl or propyl ester (the chemical process being called (trans)esterification). Biodiesel has a lower boiling point and viscosity than SVO. Pure biodiesel is marketed as B100 at the gasoline stations.
Chemically processed renewable oils can be produced in small scale in a modular plant. This is especially interesting in remote locations. It is typically applicable to produce bio-diesel. Such a modular plant can be combined with a modular fast-deploy emulsion plant. When bio-diesel would be combined with a straight vegetable oil, the renewable oil feedstock can be split into two flows, i.e. an untreated straight vegetable oil flow which goes directly to the emulsion plant and a flow of a bio-diesel produced in a transesterification modular unit.
Recycled vegetable oil or recycled animal fat originates from cooking such as frying or other industrial processes without intermediate processing. These recycled oils and fat could also be further chemically processed.
Hydrotreated renewable oils are paraffinic bio-based liquid oils originating from many kinds of vegetable oils, such as rapeseed, sunflower, soybean, algae, and palm oil, as well as animal fats or rests from wood processing. As well understood by the skilled person, hydrotreated renewable or vegetable oils are obtained by subjecting fatty acid containing oils, such as vegetable oils or waste fats to a hydro-processing treatment or a hydrotreatment, wherein hydrogen is used to make paraffin and cycloalkanes out of the unsaturated compounds in the oils, which typically further undergo hydrocracking or isomerization. The term “hydrotreated vegetable oil” or “HVO” also refers to recycled vegetable oil, animal fats or waste fats, that have been subject to the hydrotreatment process.
The fuel composition of the explosive emulsion composition according to the present disclosure particularly comprises between 20 wt. % and 100 wt. % of a hydrotreated vegetable oil (HVO), in view of the total weight of the fuel composition, such as between 40 wt. % and 100 wt. % or between 50 wt. % and 100 wt. % of HVO, and optionally one or more other chemically processed renewable oils, one or more straight vegetable oils (SVO) and/or one or more non-renewable oils, such as diesel or white oil. Advantageously, the combination of a fuel composition comprising a HVO and an oxidizer phase comprising ammonium nitrate and a secondary nitrate as discussed below results in an explosive emulsion composition with good stability and low viscosity, and, hence, easily pumpable.
In certain embodiments, the fuel composition consists of between 20 wt. % and 80 wt. %, particularly between 30 wt. % and 70 wt. % of a hydrotreated vegetable oil and between 20 wt. % and 80 wt. %, particularly between 30 wt. % and 70 wt. % of a non-renewable oil, particularly diesel or white oil, in view of the total weight of the fuel composition.
The organic phase can next to chemically processed renewable oils also comprise one or more straight vegetable oils. A straight vegetable oil is defined as any of a group of oils that are esters of fatty acids and glycerol and are obtained from plants and which are non-chemically processed, i.e. which has not been subject to a process which has changed the chemistry of the SVO. In particular, an SVO has not been subject to an esterification or transesterification process, or to a hydrotreatment. The straight vegetable oil is chosen from soybean oil, palm oil, rapeseed oil, canola oil, maize oil, corn oil, sunflower oil or a mixture thereof. Less preferred SVO's which are economically less attractive but which are also suitable are groundnut oil, kernel oil, virgin olive oil, oil of olive residues, karite nuts butter, castor bean oil, hydrogenated castor oil, tung nuts oil, safflower seed oil, sesame seed oil, mustard seed oil, poppy seed oil, vegetable tallow, stillingia oil, kapok oil, cottonseed oil linseed oil, hempseed oil, algae oil, rice bran oil, linseed oil, peanut oil and safflower oil or a mixture thereof.
In certain embodiments, the fuel composition consists of between 10 wt. % and 90 wt. %, between 20 wt. % and 80 wt. %, between 30 wt. % and 70 wt. % or between 40 wt. % and 60 wt. %, of one or more chemically processed renewable oils, in particular one or more hydrotreated renewable oils (HVO), and between 10 wt. % and 90 wt. %, between 20 wt. % and 80 wt. %, between 30 wt. % and 70 wt. % or between 40 wt. % and 60 wt. %, of one or more straight vegetable oils (SVO), wherein the total weight % of the one or more chemically processed renewable oils and the SVOs equals 100, all in view of the total weight of the fuel composition. Advantageously, the combination of a fuel composition comprising a HVO and a SVO, and an oxidizer phase comprising ammonium nitrate and a secondary nitrate, in particular calcium nitrate, as discussed below, allows for an even better control of the viscosity of the explosive emulsion of the present disclosure.
The straight animal fat can be cattle fat, buffalo fat, sheep fat, goats fat, pigs fat, poultry fat, camels fat, fat from other camelids, ghee fat or whale fat (blubber), fish oil or a mixture thereof. Animal fats tend to have more free fatty acids than vegetable oils do.
Furthermore, the organic phase can next to chemically processed renewable oils also comprise one or more non-renewable oils. Typical examples of commonly used non-renewable oils include diesel, paraffin wax, paraffin oil, slack wax and the like.
The organic phase of the explosive emulsion composition according to the present disclosure furthermore comprises an emulsifier which is added to prevent separation of the different phases and thus to obtain a stable emulsion. In this context, the emulsifier may be chosen from the wide range of emulsifiers known in the art to be suitable for the preparation of explosive emulsion compositions. Particularly suitable emulsifiers include PIB (polyisobutylene) derivatives such as PIBSA (polyisobutylene succinic anhydrides), sorbitan ester emulsifiers such as SMO (sorbitan monooleate) and mixtures thereof. It is however remarked that other types of emulsifiers, leading also to highly stable emulsions, could be used. The emulsifier can be bio-sourced, i.e. produced from renewable resources. When the fuel is also completely from a renewable origin, providing an emulsifier which is bio-sourced provides a fully green solution of an explosive emulsion. Typically, between 12 wt. % and 50 wt. % of a single emulsifier or a mixture of different emulsifiers in view of the total weight of the organic phase composition is present. Typical amounts of such emulsifiers in view of the total weight of the emulsion composition are between 0.5 and 5 wt. %, more in particular between 1.0 wt. % and 2.5 wt. %. In this context, it is understood that the skilled person is able to select a suitable emulsifier and its concentration without any inventive skill.
Since a mixture of a chemically processed renewable oil with straight ammonium nitrate (AN) as the sole oxidizer salt, and a commonly used emulsifier does either not form an emulsion, or if an emulsion is formed, the emulsion is not stable at all, in the context of the present disclosure, the oxidizer phase comprises next to ammonium nitrate as an oxidizer salt also a secondary nitrate salt. In the context of the present disclosure, a secondary nitrate salt refers particularly to an alkali nitrate salt, an alkaline earth nitrate salt, or a mixture thereof. Particularly preferred secondary nitrate salts include calcium nitrate (CN), sodium nitrate (SN) or a mixture thereof.
AN typically is present in an amount between 40 wt. % and up to 80 wt. % and the secondary nitrate salt is present in an amount of at least 5 wt. %, in view of the total weight of the oxidizer phase composition. In certain embodiments, the oxidizer phase comprises between 40 wt. % to 80 wt. % AN and between 5 wt. % and 50 wt. % of calcium nitrate and/or sodium nitrate, in particular between 10 wt. % and 40 wt. % of CN and/or SN, more in particular between 10 wt. % and 35 wt. % CN and/or SN, even more in particular between 15 wt. % and 35 wt. % CN and/or SN, between 10 wt. % and 30 wt. % CN and/or SN, or between 15 wt. % and 30 wt. % CN and/or SN, in view of the total weight of the oxidizer phase composition.
In certain embodiments, the oxidizer phase comprises between 40 wt. % to 80 wt. % AN and at least 10 wt. % CN, particularly between 10 wt. % and 40 wt. % CN, in view of the total weight of the oxidizer phase composition. Calcium nitrate as secondary nitrate was found to be particularly effective in obtaining stable explosive emulsions with customized viscosity, particularly when using a fuel composition consisting of 100% of one or more renewable oils, more in particular when using a fuel composition comprising HVO and SVO. In particular, the explosive emulsion composition according to the present disclosure, comprising CN as secondary nitrate salt and comprising HVO and SVO as fuels, has a viscosity between 10,000 cP and 50,000 cP, as measured with a Brookfield viscometer with spindle size 7 at a frequency of 20 rpm at 30° C.
In certain embodiments, the oxidizer phase comprises between 40 wt. % to 80 wt. % AN and at least 10 wt. % SN, particularly between 10 wt. % and 40 wt. % of SN, in view of the total weight of the oxidizer phase composition. In particular, the explosive emulsion composition according to the present disclosure, comprising SN as secondary nitrate salt, has a viscosity between 10,000 cP and 35,000 cP, as measured with a Brookfield viscometer with spindle size 7 at a frequency of 20 rpm at 30° C.
The oxidizer phase further typically comprises between 5 wt. % and 25 wt. % of (de-ionized) water in view of the total weight of the oxidizer composition. In certain embodiments, the water content of the oxidizer phase is between 10 wt. % and 20 wt. %, more in particular between 12 wt. % and 17 wt. %, such as about 15 wt. %, in view of the weight of the oxidizer composition.
It is remarked that any combination of different chemically processed renewable oils or a combination of one or more different chemically processed renewable oils with an SVO or a non-renewable oil, within the ranges claimed and as mentioned above, is possible, this depending on the viscosity necessary for the application. The viscosity depends on the amount of oil present in the fuel phase, which is related to the amount of secondary salt present in the oxidizer phase, particularly the amount of calcium nitrate in the oxidizer phase. Bulk applications require a lower viscosity while for packaged emulsion (cartridge) applications, a high viscosity is acceptable.
In certain embodiments, the explosive emulsion composition according to the present disclosure comprises
In particular embodiments, the explosive emulsion composition according to the present disclosure comprises
Advantageously, by combining the use of calcium nitrate, particularly at levels of between 10 wt. % and 50 wt. % of the oxidizer phase, such at levels between 15 wt. % and 40 wt. % or between 15 wt. % and 35 wt. %, with a fuel composition consisting of SVOs and chemically processed renewable oil, such as HVO, wherein the SVOs make up at least 30 wt. %, 40 wt. % or at least 50% of the fuel composition, a green and stable explosive emulsion composition is obtained with customizable viscosity.
The present disclosure also provides for a method for controlling the viscosity and stability of an explosive emulsion composition, particularly wherein the explosive emulsion composition comprises an oxidizer phase comprising ammonium nitrate and a secondary salt, and an organic phase comprising a fuel composition, said fuel composition comprising HVO and, optionally, a SVO or another oil with a viscosity of at least 20 cP at 40° C., wherein the method comprises the steps of varying the concentration of HVO in the fuel composition and varying the concentration of the secondary salt, in particular the concentration of calcium nitrate in the oxidizer phase. In particular, by reducing the concentration of the hydrotreated vegetable oil in the organic phase and by concomitantly increasing the concentration of a straight vegetable oil (SVO) or of another oil with a viscosity of at least 20 cP at 40° C., the viscosity of the explosive emulsion will be increased, and vice versa. In particular, increasing the amount of the secondary salt, in particular calcium nitrate, such as to concentrations of at least about 25 wt. % or 30 wt % in view of the composition of the oxidizer phase, lowers the viscosity of the explosive emulsion composition.
The explosive emulsion composition typically has a viscosity of between 10 000 and 200 000 cP, as measured with a Brookfield viscometer with spindle size 7 and frequency of 20 rpm, particularly as measured at a temperature between 20° C. and 80° C. More in particular, the explosive emulsion composition according to the present disclosure has a viscosity of between 20 000 and 120 000 cP, as measured with a Brookfield viscometer with spindle size 7 and frequency of 20 rpm at a temperature of 30° C. and/or has a viscosity of between 20 000 and 80 000 cP, as measured with a Brookfield viscometer with spindle size 7 and frequency of 20 rpm at a temperature of 70° C.
In certain embodiments, the explosive emulsion composition according to the present disclosure may comprise
In certain embodiments of an explosive composition according to the present disclosure, the explosive emulsion comprises
In Table 1 below, an overview is given of the tested samples of explosive emulsions, produced by the following procedure:
It is remarked that the steps, times and rpm used depend obviously on the equipment used, protocol developed, etc, and are not essential parts of this disclosure and can consequently be varied.
The following materials are used:
The following emulsifiers were used in the tests as shown in Table 2:
The following samples as produced by the procedure as described above were tested:
The shear stress stability as mentioned in Table 4 below of the different tested samples as mentioned in Table 1 was measured by the following method:
The viscosity as mentioned in Table 4 below of the different tested samples as mentioned in Table 1 was measured using the following measurement method: a spindle of a Brookfield viscometer with spindle size 7 at a frequency of 20 rpm is rotated for 30 s (this time being an optional choice in the viscometer settings). The viscosity of the following emulsions is measured as:
Out of results as shown in Table 4, it can be concluded that:
| Number | Date | Country | Kind |
|---|---|---|---|
| 21161190.0 | Mar 2021 | EP | regional |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/EP2022/055786 | 3/8/2022 | WO |
