WO2016029089A1

WO2016029089A1 - Method for removing materials from coal fire generated catalysts

Info

Publication number: WO2016029089A1
Application number: PCT/US2015/046248
Authority: WO
Inventors: Gerald Stanley ROSE Sr.; Bobby Joel IVEY Jr.; Kevin Aaron Rose
Original assignee: Jsk Capital Llc
Priority date: 2014-08-22
Filing date: 2015-08-21
Publication date: 2016-02-25

Abstract

A method for removing iron, calcium and various metals from coal fire generated catalysts. With the use of urea sulfate, urea hydrochloride and/or pH lowering compound in combination with a reducing compound, and chelating compound, the cleaning redeposition problem can be solved while minimizing the environmental impact from process chemicals. The urea sulfate or urea hydrochloride along with a reducing compound will solubilize, then converts, the metals into a form that will allow the chelate compound to safely remove the metals from the Catalyst. The solubilized metals are combined with the chelate to form an inert compound that will not redeposit back onto the substrate, thereby, allowing the materials to be removed from the system safely and efficiently with shorter process times.

Description

METHOD FOR REMOVING MATERIALS FROM

COAL FIRE GENERATED CATALYSTS

CROSS REFERENCE TO RELATED APPLICATIONS:

[0001] The present application claims the benefit of priority of U.S. Provisional Application No. 62040548, filed on August 22, 2014, the entirety of which is incorporated herein by reference.

BACKGROUND OF THE INVENTION:

[0002] The present invention relates generally to a method for removing iron, calcium and various metals from coal fire generated catalysts. [0003] Coal fire generated catalysts filter unwanted soot and debris from the energy producing coal fire operations. This debris is contaminated with iron, calcium and other metals. These materials are difficult to remove as they are chemically bound to the filters by the attraction of the catalysts. Once the metals have been removed from the catalysts, often with dangerous and environmentally unfriendly compounds, the metals tend to redeposit back onto the catalysts filter during the cleaning and regeneration process, which creates the need to reprocess the filters. This reprocessing is both time consuming, inefficient and dangerous to the environmental waste system. The chemicals used are very corrosive to equipment and the metal catalysts. [0004] Typical methods of removal include submerging catalysts in low pH acid environments and high pH caustic cleaning solutions at high or low temperature to remove the metals away from the catalysts. However, there is no mechanism at present to improve the reduction mechanism and prevent redeposition of the metals back onto the catalysts. These existing methods do not adequately solubilize or reduce the metals to allow for efficient removal. Due to this fact, the catalysts are subjected to multiple process steps using various cleaning methods and chemicals. This also creates more corrosive environment. [0005] Accordingly, there remains a need for an improved way to removing and reduce iron, calcium and various metals from coal fire generated catalysts more efficiently and safely.

SUMMARY OF THE INVENTION: [0006] The following presents a simplified summary of the invention in order to provide a basic understanding of some aspects of the invention. This summary is not an extensive overview of the invention. It is not intended to identify key or critical elements of the invention or to delineate the scope of the invention; its sole purpose is to present concepts of the invention in a simplified form as a prelude to the more detailed description that is subsequently presented.

[0007] Typical coal fire catalyst cleaning methods include submerging catalysts in cleaner solution at high or low temp to remove unwanted metals away from the coal fire generated catalysts. There is no mechanism at present to improve metals reduction or prevent redeposition of the metals back onto the catalysts. These existing methods do not adequately solubilize, or chemically reduce metals to allow for efficient removal. Due to this fact, the catalysts are subjected to multiple process steps using various cleaning methods and chemicals. [0008] Many, if not all, of these processes are improved with the present invention. The invention includes, but not limited to, the use of about 1% to about 5% of a pH lowering solution, including any suitable acid, including without limitation acetic, citric, sulfamic, hydrochloric, phosphoric, sulfuric, nitric, or formic acid. In some instances the use of about 1 % to about 5% of an organic salt comprising urea sulfate or urea hydrochloride have been utilized where reduced corrosion and environmental concerns are warranted. In addition to pH lowering compounds, reducing agents are needed. A "reducing agent" (also called a reductant or reducer) is an element or compound that loses (or "donates") an electron to another chemical species in a redox chemical reaction. Since the reducing agent is losing electrons, it is said to have been oxidized.

[0009] If any chemical is an electron donor (reducing agent), another must be an electron recipient (oxidizing agent). A reducing agent is oxidized because it loses electrons in the redox reaction. Thus reducers are "oxidized" by oxidizers and oxidizers are "reduced" by reducers; reducers are by themselves reduced (have more electrons) and oxidizers are by themselves oxidized (have fewer electrons). A reducing agent typically is in one of its lower possible oxidation states and is known as the electron donor. A reducing agent, which can include, but is not limited to, such chemicals as stannous chloride, erythorbic acid or oxalic acids, is used at about 1% to about 5%, to effectively convert the chemical charge of the unwanted iron metal content into a form that can be easily treated and removed, such as within a wastewater treatment facility. In one embodiment, this converted form is less likely to redeposit back onto the substrate thru the use of about 1% to about 3% of a chelating chemical. "Chelation" describes a particular way that ions and molecules bind metal ions. One of the most popular chelants is EDTA (or ethylenediamine tetraacetic acid). Alternatives to EDTA include phosphates, NTA (or nitrilotriacetic acid), citrates, silicates, and polymers of acrylic an maleic acid. According to the International Union of Pure and Applied Chemistry (lUPAC), chelation involves the formation or presence of two or more separate coordinate bonds between a polydentate (multiple bonded) ligand and a single central atom. Usually these ligands are organic compounds, and are called chelants, chelators, chelating agents, or sequestering agentsThe chelant is added to further bind up excess materials and prevent redeposition onto the substrate. The chelant acts in a synergistic manner to improve overall performance and efficiency of the reduction and cleaning process

[0010] According to its major aspects and briefly stated, the present invention includes a method for removing iron, calcium and various metals from coal fire generated catalysts. With the use of urea sulfate, urea hydrochloride and/or pH lowering compounds in combination with a chelating compound, reducing agent chemistries the cleaning redeposition problem can be solved while improving overall cleaning efficiency and minimizing the environmental impact from process chemicals. Acids or acid salts break the metal bonds away from the catalysts allowing the reducing agent to solubilize the unwanted metals into a form that will allow the chelate compound to effectively complex the metals away from the catalyst. The solubilized metals combine with the chelate to form an inert compound that will not redeposit back onto the substrate, thereby, allowing the materials to be removed from the system safely and economically with shorter process times. The urea sulfate or urea hydrochloride is odor and phosphate free. Urea sulfate or urea hydrochloride contributes much lower BOD/COD to the waste system than traditional acid cleaning compounds. In addition, offering much lower corrosive characteristics to skin and metals while being particularly effective in removing iron, calcium and other metals. [0011] In embodiment of the present invention, a method for removing iron, calcium and other metals from coal fired catalysts may comprise the following steps: 1) providing a catalyst to a substrate including an amount of metals; 2) introducing an effective amount of acid or acid salt, chemical reducing compound, and chelate convert the metals to a solubilized form capable of being attracted by a chelating agent; and 3) introducing an effective amount of a chelating agent to the solubilized form of metals to form an inert compound that will not redeposit on the catalyst substrate.

[0012] Other features and their advantages will be readily apparent to those skilled in the arts, techniques and equipment relevant to the present invention from a careful reading of the Detailed Description of Preferred Embodiments.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENT

[0013] According to its major aspects and briefly stated, the present invention includes a method for removing iron, calcium and various metals from coal fire generated catalysts while preventing redeposition of unwanted metals back onto the substrate. With the use of urea sulfate, urea hydrochloride and/or pH lowering compounds in combination with a chemical reducing compound and chelating compound, the cleaning redeposition problem can be solved while improving overall cleanability and minimizing the environmental impact from process chemicals. The urea sulfate or urea hydrochloride or pH towering compounds removes the unwanted metals, the reduction compound alters, then converts the metals into a form that will allow the chelate compound to safely remove the metals from the catalyst. The solubilized metals are combined with the chelate to form an inert compound that will not redeposit back onto the substrate, thereby, allowing the materials to be removed from the system safely and economically with shorter process times. Both urea sulfate or urea hydrochloride is odor and phosphate free. The acid salt contributes much lower BOD/COD to the waste system than traditional acid cleaning compounds. In addition, urea sulfate or urea hydrochloride offers much lower corrosive characteristics to skin and metals while being particularly effective in solubilizing iron, calcium and other metals.

[0014] Many, if not all, of these processes are improved with the present invention. The invention includes, but not limited to, the use of about 1% to about 5% of a pH lowering solution, including any suitable acid, such as acetic, citric, sulfamic, hydrochloric, phosphoric, sulfuric, nitric, or formic acid. In some instances the use of about 1% to about 5% of an organic salt comprising urea sulfate or urea hydrochloride have been utilized where reduced corrosion and environmental concerns are warranted. In addition to pH lower compounds, reducing agents are needed. A "reducing agent" (also called a reductant or reducer) is an element or compound that loses (or "donates") an electron to another chemical species in a redox chemical reaction. Since the reducing agent is losing electrons, it is said to have been oxidized.

[0015] If any chemical is an electron donor (reducing agent), another must be an electron recipient (oxidizing agent). A reducing agent is oxidized because it loses electrons in the redox reaction. Thus reducers are "oxidized" by oxidizers and oxidizers are "reduced" by reducers; reducers are by themselves reduced (have more electrons) and oxidizers are by themselves oxidized (have fewer electrons). A reducing agent typically is in one of its lower possible oxidation states and is known as the electron donor. A reducing agent, which can include, but is not limited to, such chemicals as stannous chloride, erythorbic acid or oxalic acids, is used at about 1% to about 5%, to effectively convert the chemical charge of the unwanted iron metal content into a form that can be easily treated and removed, such as within a wastewater treatment facility. In one embodiment, this converted form is less likely to redeposit back onto the substrate thru the use of about 1% to about 3% of a chelating chemical. "Chelation" describes a particular way that ions and molecules bind metal ions. One of the most popular chelants is EDTA (or ethylenediamine tetraacetic acid). Alternatives to EDTA include phosphates, NTA (or nitrilotriacetic acid), citrates, silicates, and polymers of acrylic and maleic acid. According to the International Union of Pure and Applied Chemistry (lUPAC), chelation involves the formation or presence of two or more separate coordinate bonds between a polydentate (multiple bonded) ligand and a single central atom. Usually these ligands are organic compounds, and are called chelants, chelators, or chelating agents. The chelant is added to further bind up excess materials and prevent redeposition onto the substrate. The chelant acts in a synergistic manner to improve overall performance and efficiency of the reduction and cleaning process.

[0016] In an embodiment of the present invention, a method for removing iron, calcium and other metals from coal fired catalysts may comprise the following steps: 1) providing a catalyst to a substrate, such as a catalytic filter, including an amount of metals; 2) introducing an effective amount of acid/acid salt, reducing compound in aqueous solution to the catalyst substrate to remove the metals and to convert the metals to a solubilized form capable of being attracted by a chelating agent; and 3) introducing an effective amount of a chelating agent to the solubilized form of metals to form an inert compound that will not redeposit on the catalyst substrate. [0017] In another embodiment of the present invention, a method for removing iron, calcium and other metals from coal fired catalysts may comprise the following steps: 1) providing an amount of catalyst to a substrate, wherein said amount of catalyst includes an amount of iron, calcium, and/or other metals; 2) introducing an effective amount of removing mixture, including an effective amount of urea sulfate, urea hydrochloride or pH lowering compound in aqueous solution to the amount of catalyst; 3) introducing an effective amount of a reducing agent to the removing mixture; and 4) reducing the amount of iron, calcium, and/or other metals with the removing mixture to convert the amount of iron, calcium, and/or other metals to a solubilized form.

[0018] The method may further comprise the following additional steps: 5) introducing an effective amount of anti-depositing agent to the aqueous solution, including a chelating agent to the solubilized form of the amount of iron, calcium and/or other metals to form an inert compound having properties that prevent the inert compound from depositing on the substrate.

[0019] A listing of results obtained from testing various metal removing agents is shown in the table below and in the attached figures.

[0020] In the first test, shown below, a catalyst or catalytic filter, adulterated with soot ash containing large amounts of iron, calcium and various other metals, was placed in a 500 ml beaker containing various acids and acid/reducing compounds, and chelate combinations at about 80° Celsius for about 45 min. The filters were then removed to measure metals and dirt removal ability of the acid and acid salt reducing compounds, and chelate combinations. The wastewater was also analyzed visually to confirm the removed materials had not redeposited back onto the catalyst surface. Generally speaking, the test is measure the cleaning ability of acid and acid salt, reducing compounds, and chelate combinations on coal fire generated catalysts filters. TABLE I

Test Performance of Ultra Chelate 720 with Biocid and Sulfamic Acid

[0021] The cleaning abilities of the materials in this test was determined by observation when comparing the visible differences between the filters treated with the method and mixtures described above in Table I. Photographs supporting the results above and below (Table II) are included as Figures 1-6 in the US Provisional 62040548, filed on August 22, 2014, and are incorporated herein by reference. The products Ultra Biocid, Ultra Biocid AGL and Ultra Chelate referred to in Tables I and II are commercially available from UCI International Inc., Ultra Chem Industries Inc., and JSK Capital LLC. As used herein, the term Ultra Chelate 720 is a substance in the chelate chemical family; Ultra Biocid is urea sulfate; and Ultra Biocid AGL is urea hydrochloride. The Ultrachelate 720 is based on the M$D$ that indicates it as organic and inorganic salts combined with an acrylic polymer blend. [0022] The numbers in the tables denote the quantity of chemical used in the test. In this case, grams/liter. The tables demonstrate the presences of a synergistic effect achieved by combining certain compounds, which yielded better results than just utilizing an acid solution. These show the products performed better in combination than as individual components.

[0023] Notably, both the Ultra Biocid (urea sulfate) and sulfamic acid mixtures (Baths 6 and 7, respectively) performed better than citric acid with the Ultra Chelate 720 (Bath 2), with the sulfamic acid and chelate mixture (Bath 7) performing the best of all three. However, none of these acid mixtures performed as well as Ultra Biocid (urea sulfate) or Biocid AGL (urea hydrochloride) with reducing compound, and chelant (Baths 3 and 5). Although there appeared to be some brightening with the Biocid (urea sulfate) and sulfamic acid, it was more or less turning the rust color into a pale salmon color. The Ultra Biocid AGL (urea hydrochloride) with chelant brightened to the point of an off-white color.

[0024] In a second test, the results shown below in Table II, a catalyst filter, adulterated with soot ash containing large amounts of iron, calcium and various other metals, was placed in a 500 ml beaker containing various acids and acid/chelate combinations at about 80° Celsius for about 45 min. The filters were then removed to measure metals and dirt removal ability of the acid and acid/chelate combinations. The wastewater was also analyzed visually to confirm the removed materials had not redeposited back onto the catalyst surface. Generally speaking, the test is measure the cleaning ability of acids and acid salt, reducing compounds, and chelate combinations on coal fire generated catalysts filters. TABLE II

[0025] These results show there is a synergistic affect between the Ultra Biocid AGL or Ultra Biocid and Ultra Chelate 720 (Baths 3 and 5) with reducing compound. Only when the two products are combined is there visually any real cleaning on the catalyst. There is a faint amount of material coming off with the citric acid and Ultra Chelate 720, but not significant. This can be noted not only on the cleaned catalyst panels, but also in the spent chemical bathes. The most significant cleaning was achieved at 4 gm/L of Ultra Biocid AGL or Ultra Biocid with reducing compound, and Ultra Chelate 720.

[0026] Those skilled in the relevant arts will appreciate from the foregoing description of preferred embodiments that substitutions and modification can be made without departing from the spirit and scope of the invention which is defined by the appended claims.

Claims

WHAT IS CLAIMED IS:

1. A method of removing materials from catalysts, comprising the steps of:

providing an amount of catalyst to a substrate, wherein said amount of catalyst includes an amount of iron, calcium, and/or other metals;

introducing an effective amount of removing mixture, said removing mixture including an effective amount of urea sulfate, urea hydrochloride or pH lowering compound to said amount of catalyst;

introducing an effective amount of a reducing agent to said removing mixture; and

reducing said amount of iron, calcium, and/or other metals with said removing mixture to convert said amount of iron, calcium, and/or other metals to a solubilized form.

2. The method as recited in claim 1, wherein said substrate is a catalytic filter.

3. The method as recited in claim 2, wherein said catalytic filter is a fabric filter.

4. The method as recited in claim 1, wherein said urea hydrochloride is Ultra Biocid AGL, and wherein said urea sulfate is Ultra Biocid.

5. The method as recited in claim 1, wherein said pH lowering compound is acetic, citric, sulfamic, hydrochloric, phosphoric, sulfuric, nitric, or formic acid.

6. The method as recited in claim 1, wherein said effective amount of urea hydrochloride, urea sulfate or pH lowering compound is about 1% to about 5% of said removing mixture.

7. The method as recited in claim 6, wherein said effective amount of urea hydrochloride, urea sulfate or pH lowering compound is at a concentration of about 4 gm/L.

8. The method as recited in claim 1, further comprising the step of introducing an effective amount of an anti-depositing agent to said solubilized form of said amount of iron, calcium and/or other metals to form an inert compound having properties that prevents said inert compound from depositing on said substrate.

9. The method as recited in claim 8, wherein said anti-depositing agent is a chelating agent.

10. The method as recited in claim 9, wherein said chelating agent is selected from EDTA, a phosphate compound, NTA, a citrate compound, a silicate compound, a polymer of acrylic and maleic acid, and organic and inorganic salts combined with an acrylic polymer blend.

11. The method as recited in claim 9, wherein said chelating agent is Ultra Chelate 720.

12. The method as recited in claim 9, wherein said effective amount of chelating agent is about 1% to about 3% of said anti-depositing agent.

13. The method as recited in claim 12, wherein said chelating agent is

Ultra Chelate 720 at a concentration of about 10 gm/L.

14. The method as recited in claim 1, wherein said effective amount of urea hydrochloride is introduced at an elevated temperature.

15. The method as recited in claim 14, wherein said elevated temperature is about 80°C.

16. The method as recited in claim 1, wherein said reducing agent is stannous chloride, erythorbic acid or oxalic acid.

17. The method as recited in claim 1, wherein effective amount said reducing agent is at about 1 % to about 5% of said removing mixture.

18. A mixture for removing materials from catalysts, comprising:

a synergistic combination of an amount of urea hydrochloride, urea sulfate or pH lowering compound, an amount of a reducing agent, and an amount of a chelating agent.

19. The mixture as recited in claim 18, wherein said amount of urea hydrochloride, urea sulfate or pH lowering compound is about 4.0 gm/L

20. The mixture as recited in claim 18, wherein said amount of urea hydrochloride, urea sulfate or said pH lowering compound is about 1% to about 5% of said combination.

21. The mixture as recited in claim 18, wherein said amount of chelating agent is about 10.0 gm/L.

22. The mixture as recited in claim 18, wherein said amount of chelating agent is about 1% to about 3% of said combination.

23. The mixture as recited in claim 18, wherein said amount of a reducing agent is about 1% to about 5% of said combination.