Hydrogen sulfide scavenger

Abstract

The present disclosure is related to a family of metals chelates for use as a hydrogen sulfide scavenger in asphalt, and the preparation thereof. The metal chelates, in particular amino acid metal chelates, are particularly efficient at reducing the hydrogen sulfide emissions of asphalt.

Claims

1. A scavenger composition comprising: 5 wt % to 90 wt %, based on total weight of the composition, of a metal chelate chosen from the group consisting of Copper Aspartate; Copper Gluconate; Copper Bis-Glycinate; Iron Aspartate; Iron Glycinate; Iron Fumarate; Iron Gluconate; Molybdenum Chelate; Molybdenum Trit; Zinc Arginate; Zinc Ascorbate; Zinc Aspartate; Zinc Gluconate; Zinc Bis-Glycinate; Zinc Methionate; Zinc Picolinate; and mixtures thereof; and a solvent having a flash point compatible with asphalt or bitumen; wherein the scavenger composition is able to reduce hydrogen sulfide emissions from asphalt.

2. The scavenger composition of claim 1, wherein the metal chelate is selected from the group consisting of copper bis-glycinate and zinc bis-glycinate.

3. A method of reducing hydrogen sulfide emission from asphalt or from the preparation of asphalt, comprising adding the scavenger composition of claim 1 to asphalt.

4. The method of claim 3, wherein the asphalt further comprises polyphosphoric acid.

Description

EXAMPLES

Example 1

(1) Hydrogen sulfide emissions were measured from asphalt samples containing a metal chelate versus a control containing no metal chelate. Three asphalt samples were prepared and their hydrogen sulfide emissions measured after 1 hour in storage. To two samples, 0.5% metal chelate additive was addedCuGlyc (copper bis-glycinate) and ZnGlyc (zinc bis-glycinate), respectively. The hydrogen sulfide emissions were measured again after 5 minutes and 1 hour. Table 1 lists the results. The addition of the metal chelate showed significant reduction in hydrogen sulfide emissions.

(2) TABLE-US-00002 TABLE 1 Hydrogen Sulfide Emission H.sub.2S (ppm) H.sub.2S (ppm) H.sub.2S (ppm) 5 minutes 1 hour after Storage at after adding 160, one addition of scavenger % Additive Temp hour scavenger material 0 Control 180 C. 16 10 0.5 CuGlyc 180 C. 12 4 1 0.5 ZnGlyc 180 C. 10 5 1

Example 2

(3) Additional metal chelates that may be used in asphalt, or the preparation thereof, are listed in Table 2.

(4) TABLE-US-00003 TABLE 2 Metal Chelates Metal Chelating agent Chromium Amino Acid Arginate Chloride Dinicotinate/Glycinate Picolinate Nicotinate TritChromium Yeast Copper Amino Acid Aspartate Carbonate Citrate Gluconate Sulfate Yeast Iron Amino Acid Aspartate Bis-Glycinate Citrate Fumarate Gluconate Sulfate Yeast Manganese Amino Acid Aspartate Carbonate Citrate Gluconate Sulfate Yeast Molybdenum Amino Acid TritMolybdenum Yeast Sodium Molybdate Selenium Amino Acid Aspartate L-Selenomethionine Yeast Sodium Selenate Sodium Selenite Strontium Aspartate Citrate Glycinate Vanadium Amino Acid Citrate Bis-Maltolato Oxo Vanadium Vanadyl Sulfate Sodium Metavanadate Zinc Acetate Arginate Amino Acid Ascorbate Aspartate Gluconate Glycinate Methionate Picolinate Sulfate Yeast