阅读说明：本技术 防止在热柏油或沥青的生产中的硫化氢排放 (Prevention of hydrogen sulfide emissions in the production of hot asphalt or bitumen ) 是由 沃尔弗拉姆·弗兰克 希尔德·布雷克达尔托默森 于 2018-07-17 设计创作，主要内容包括：本申请涉及一种用于防止在温度为150至200℃的热柏油或沥青的生产中的硫化氢排放的方法,其中所述方法包括以下步骤：提供柏油或沥青混合物,将所述混合物加热直到150至200℃的温度,和在将所述柏油或沥青混合物混合的同时加入硝酸钙水溶液或硝酸钙粉末。本申请还涉及硝酸钙水溶液或硝酸钙粉末在温度为150至200℃的热柏油或沥青的生产中在将柏油或沥青混合物混合期间用于防止硫化氢排放的用途。(The present application relates to a method for preventing hydrogen sulphide emissions in the production of hot asphalt or bitumen at a temperature of 150 to 200 ℃, wherein the method comprises the steps of: providing asphalt or bitumen mixture, heating the mixture up to a temperature of 150 to 200 ℃, and adding an aqueous solution of calcium nitrate or calcium nitrate powder while mixing the asphalt or bitumen mixture. The application also relates to the use of an aqueous calcium nitrate solution or calcium nitrate powder for preventing hydrogen sulphide emissions during mixing of asphalt or bitumen mixtures in the production of hot asphalt or bitumen at temperatures of 150 to 200 ℃.)

1. A method for reducing hydrogen sulfide emissions in the production of hot asphalt or bitumen, wherein the method comprises the steps of:

-providing asphalt or bitumen mixture;

-heating the mixture to a temperature of 150 to 200 ℃;

-adding an aqueous calcium nitrate solution or calcium nitrate powder while mixing the asphalt or bitumen mixture.

2. The method of claim 1 wherein calcium nitrate is added in an amount of 0.5 to 2.0mg per mg sulfide present in the asphalt or bitumen mixture.

3. The method of claim 2 wherein calcium nitrate is added in an amount of about 1mg per mg sulfide present in the asphalt or bitumen mixture.

4. The method of any one of claims 1 to 3, wherein the calcium nitrate powder has a water content of 1 to 33 wt.%.

5. The method of any one of claims 1 to 3, wherein the concentration of the aqueous calcium nitrate solution is 45 to 55 weight percent calcium nitrate and 45 to 55 weight percent water.

6. Use of an aqueous calcium nitrate solution or calcium nitrate powder added during mixing of asphalt or bitumen mixtures in the production of hot asphalt or bitumen at a temperature of 150 to 200 ℃ for preventing the emission of hydrogen sulphide.

7. Use according to claim 6, wherein calcium nitrate is used in an amount of 0.5 to 2.0mg per mg of sulphide present in the asphalt or bitumen mixture.

8. Use according to claim 7, wherein calcium nitrate is used in an amount of about 1mg per mg of sulphide present in the asphalt or bitumen mixture.

9. Use according to any one of claims 6 to 8, wherein calcium nitrate powder with a water content of 1 to 33% by weight is used.

10. Use according to any one of claims 6 to 8, wherein an aqueous calcium nitrate solution is used having a concentration of 45 to 55% by weight of calcium nitrate and 45 to 55% by weight of water.

Technical Field

The present application relates to the prevention of hydrogen sulphide (H) in the production of hot asphalt (bittumen) or bitumen (asphalt), more particularly hot asphalt or bitumen at a temperature of 150 to 200 ℃₂S) is discharged.

Background

Hydrogen sulfide (H)₂S) is a naturally occurring gas present in a variety of crude oils. It is also formed by the degradation of sulfur compounds in the oil when exposed to high temperatures or catalysts during the refining of the oil. The main blending component for bitumen production, the Vacuum Tower Bottoms (VTB), has a particularly high H₂S concentration because they are not subjected to a process for removing H by distillation, stripping and desulfurization₂And (5) additional processing of S. VTBs are among the heaviest products from the refining column and are typically products in which the sulfur compounds are concentrated. Due to the high viscosity of bitumen, it is stored at high temperatures (i.e., 149 to 204 ℃) that are high enough to promote further thermal cracking of sulfur-containing compounds and additional H₂And (4) forming S. H₂The amount of cracking and generation of S depends on the structure of the sulphur compounds present in the oil and on the temperatures involved during the treatment. H₂S has a tendency to migrate from the liquid phase to the gas phase above the oil. Certain tank conditions such as increased liquid volume, agitation and elevated temperature may be achieved by altering H₂Distribution coefficient of S (i.e. H)₂The proportion of S in the liquid and vapor phases of the crude oil) makes this existing hazard worse, favoring the vapor space. The pitch has a large amount of H in the gas phase₂And S is distributed. Typically, 1ppm of H in the liquid phase of the bitumen₂S correlates with 400ppm in the gas phase. The bitumen may therefore contain very high levels of H in the gas phase₂S, even above 3% (30,000ppm), which may lead to various problems and risks, such as personnel involved in their storage, handling and transportation (e.g. workers in refineries and road operations) andand to some extent the safety of persons living in the area of such installations and construction sites. Exposure to already very low levels of H₂S may have significant health effects and long term exposure produces disease. H₂S is particularly harmful because it reduces olfaction at concentrations as low as 30ppm, and death may occur within a few breaths at a concentration of 700 ppm.

Today, a variety of chemicals are used to prevent the emission of hydrogen sulfide, such as caustic, peroxides, formaldehyde, nitrites, and amines, from hot asphalt or bitumen mixtures.

WO2005065177 discloses a process for reducing hydrogen sulphide emissions from bitumen comprising reacting an inorganic or organic metal salt H₂S scavenger added to asphalt, wherein the metal salt H₂The metal in the S scavenger is selected from the group consisting of: zinc, cadmium, mercury, copper, silver, nickel, platinum, iron, magnesium and mixtures thereof, in particular selected from the group consisting of: zinc oxide, cadmium oxide, copper oxide, magnesium oxide, and mixtures thereof.

US20060116450 discloses the use of a sulfur emission reducing additive in crude oil fractions, such as asphalt, wherein the emission reducing additive comprises a dispersion of a metal oxide, specifically selected from zinc oxide, iron oxide, aluminum oxide and combinations thereof.

EP0421683 discloses a process for reducing H in bitumen₂A method of S release comprising introducing an oil soluble metal carboxylate into hot asphalt, wherein in particular the metal in the carboxylate is zinc, iron, copper or zirconium.

However, a problem with these compounds is that they are harmful or difficult to handle.

It is therefore an object of the present application to provide a solution for preventing the formation of hydrogen sulphide in the production of hot asphalt or bitumen.

SUMMARY

According to a first aspect of the present application, there is provided a method for preventing hydrogen sulphide emissions in the production of hot asphalt or bitumen at a temperature of from 150 to 200 ℃, wherein the method comprises the steps of:

-providing asphalt or bitumen mixture;

-heating the mixture to a temperature of 150 to 200 ℃;

-adding an aqueous solution of calcium nitrate or calcium nitrate powder while mixing the asphalt or bitumen mixture.

When the bitumen or asphalt mixture is heated to a temperature of 150 to 200 ℃ to maintain its workability, sufficient heat is present to oxidize the hydrogen sulfide to sulfate by the calcium nitrate added during the mixing process. The hydrogen sulphide formed is dissolved in the water present in the asphalt or bitumen mixture. Thus, the material subsequently treated with calcium nitrate is S^2-。S^2-Oxidized in the organic matrix because calcium nitrate is also soluble in the organic matrix. The reaction product formed is CaSO mixed in hot asphalt or bitumen₄(gypsum) whereby no waste is produced.

The calcium nitrate powder refers to calcium nitrate particles with the particle size of less than 0.5 mm.

In one embodiment of the method according to the present application, calcium nitrate is added in an amount of 0.5 to 2.0mg per mg of sulphide present in the bitumen or asphalt mixture. More specifically, calcium nitrate is added in an amount of about 1mg per mg of sulphide present in the bitumen or asphalt mixture.

In one embodiment of the method according to the present application, the calcium nitrate powder has a water content of 1 to 33% by weight.

In one embodiment of the method according to the present application, the concentration of the aqueous calcium nitrate solution is 45 to 55 weight% calcium nitrate and 45 to 55 weight% water.

According to a second aspect of the present application, the use of an aqueous calcium nitrate solution or calcium nitrate powder during mixing of asphalt or bitumen mixtures in the production of hot asphalt or bitumen at temperatures of 150 to 200 ℃ for reducing hydrogen sulphide emissions is described.

In a particular use according to the present application, calcium nitrate is used in an amount of 0.5 to 2.0mg per mg sulphide present in the bitumen or asphalt mixture.

In a more specific use according to the present application, calcium nitrate is used in an amount of about 1mg per mg of sulphide present in the bitumen or asphalt mixture.

In one possible use according to the present application, calcium nitrate powder with a water content of 1 to 33 wt.% is used.

In another possible use according to the present application, an aqueous calcium nitrate solution having a concentration of 45 to 55 weight% calcium nitrate and 45 to 55 weight% water is used.

Detailed Description

Described herein is a method for preventing hydrogen sulfide (H) in the production of hot asphalt or bitumen according to the present application₂S) is used. More specifically, the main objective of the process according to the present application is to counteract H from the hot asphalt or bitumen mixture₂S emission, rather than eliminating the emission. The method comprises the following steps:

-preparing or providing an asphalt or bitumen mixture,

-heating the asphalt or bitumen mixture to a temperature of 150 to 200 ℃, and

-adding an aqueous solution of calcium nitrate or calcium nitrate powder while mixing the asphalt or bitumen mixture.

More specifically, calcium nitrate is added in an amount of 0.5 to 2.0mg and most specifically in an amount of about 1mg per mg of sulphide present in the asphalt or bitumen mixture.

In the context of the present invention, the term "asphalt or bituminous mixture" is the residue and heaviest fraction obtained during the refining of crude oil. It contains very long chain hydrocarbon compounds that do not vaporize during the refining process and, in addition, mineral impurities and sulfur compounds. It should be understood that asphalt or bitumen mixtures are not composed of homogeneous single hydrocarbon compounds.

Suitable measurements and ASTM standard methods for determining the sulfide content of petroleum products are known. For bitumen and asphalt, the so-called and well-known "can test" method is generally used, in which a sample, for example bitumen or asphalt, is subjected toThe asphalt sample was placed in a metal container and, after heating the container, the H was measured by measuring the headspace in the metal container₂Determination of H of sample by S content₂And (4) discharging the S. For example, measurements of hydrogen sulfide in the gas phase may be made according to ASTM D5705-15.

More specifically, the hydrogen sulfide concentration in the bitumen or asphalt can be determined by the so-called Baker Hughes field tank test method (see, e.g., Draper and Stark,2012, incorporated herein by reference, http:// www.digitalrefining.com/alarm/1000336 #. WWxveYSGPRY) which allows a more repeatable means of establishing a gas phase in the sample container. In this process, quart-sized metal cans half-filled with bitumen are used, the bitumen being most suitably sampled on site, fresh bitumen being taken directly from the unit to the sampling vessel. The metal can is then sealed and shaken using a specially designed container that enables the sample to be thoroughly stirred while protecting the operator from accidental leakage of hot asphalt. The samples were tested using the gas detection tubes immediately after storage at the relevant temperature and time period.

When calcium nitrate powder is used, the water content of the calcium nitrate powder is preferably 1 to 33% by weight. The particle size of the calcium nitrate powder is not critical.

When an aqueous solution of calcium nitrate is used, the concentration of calcium nitrate therein is preferably 45 to 55% by weight, and the remainder is 45 to 55% by weight of water.

The application also relates to the use of an aqueous calcium nitrate solution of calcium nitrate powder during mixing of asphalt or bitumen mixtures in the production of hot asphalt or bitumen mixtures, wherein the temperature of the hot asphalt or bitumen mixture is from 150 to 200 ℃ to prevent the emission of hydrogen sulphide.

In particular, calcium nitrate is used in an amount of 0.5 to 2.0mg and more particularly in an amount of about 1mg per mg of sulphide present in the asphalt or bitumen mixture.

When calcium nitrate powder is used, the water content of the calcium nitrate powder is 1 to 33% by weight. When an aqueous solution of calcium nitrate is used as an alternative, the concentration of the solution is 45 to 55 weight% calcium nitrate and 45 to 55 weight% water.

Examples

Using an asphalt emulsion known as Elastopaz, an aqueous calcium nitrate solution and an aqueous sulfide solution and

experiments were performed. Elastopaz is a single component asphalt polymer liquid film commercialized by israel Pazkar ltd.

Is manufactured by American Co

A commercial gas sensing tube.

Approximately 100ml of Elastopaz was added to a 600ml beaker. The watch glass was placed over the beaker and the beaker was placed on a hot plate with a magnetic stirrer. Elastopaz was heated to a boiling point of about 100 ℃ and an aqueous solution of calcium nitrate at a concentration of 1g/l and sodium sulfide nonahydrate at a concentration of 1g/l were added to the hot Elastopaz. To ensure proper mixing, an aqueous solution of calcium nitrate and an aqueous solution of sodium sulfide nonahydrate were added to the vortex created by the magnetic stirrer. Use of an extension hose will

Placed in the headspace above the beaker below the watch glass to measure the amount of hydrogen sulfide produced. The amount of hydrogen sulfide was measured three times in each sample in succession. The time between each measurement was 8 to 10 minutes. The samples were kept at boiling point in all measurements.

A total of 12 samples were analyzed. Four different calcium nitrate additions, namely 0ml, 2.5ml, 5ml and 10ml, equal to 0, 25, 50 and 100mg calcium nitrate per liter of Elastopaz, respectively, were performed in triplicate for each of them. Will equal 50mgS^2-To each sample was added 5ml of aqueous sodium sulfide nonahydrate solution per liter of Elastopaz.

TABLE 1

As a result shown in table 1, it was shown that the addition of calcium nitrate to hot asphalt or bitumen during the mixing process prevented the emission of hydrogen sulfide. When 2.5 and 5.0ml of aqueous calcium nitrate solution were added, the hydrogen sulfide was reduced. The addition of 10.0ml of aqueous calcium nitrate solution appeared to be an overdose.