Coating compositions containing char and methods of use thereof

Abstract

Provided here are coating compositions containing a solvent, a binder, and char particles and methods of forming a thermal protective coating on a surface using these coating compositions.

Description

COATING COMPOSITIONS CONTAINING CHAR AND METHODS OF USE THEREOFInventor: Fabrice CuoqCross-Reference to Related Applications

[0001] This application claims the benefit of and priority to U.S. Provisional Application No. 63 / 511,256, filed on June 30, 2023, which is incorporated herein by reference in its entirety.Technical Field

[0002] The disclosure relates to coating compositions containing char, particularly thermal protective coatings, and methods of use of these compositions.Background

[0003] Char is formed during the pyrolysis of biomass or mixed plastic waste. The inorganic mineral content present in the biomass or mixed plastic waste feedstock can be primarily retained in the char formed during the pyrolysis process. Char particles greater than 10 micrometers (pm) are removed during pyrolysis by processes, such as hot gas filtration and cyclone separation. Particulate solids less than 10 pm in size still remain in the pyoil. Char particles need to be removed if the pyoil is to be converted into gasoline or diesel fuel. Removal of char particles in the micron size range improves properties of the pyoil for downstream processing into other chemicals and fuels. Processing of char is expensive, and occurs either via incineration or landfilling — both of are not environmentally friendly processes.Summary

[0004] Applicant has recognized ways to recycle the char formed during the production of pyoil. Provided here are coating compositions containing char and methods of use thereof.Embodiments include a coating composition containing a solvent, a binder, and char particles. In certain embodiments, the char particles are a byproduct of processing of mixed plastic waste, or biomass, or a combination thereof. In certain embodiments, the char particles are a byproduct of fast pyrolysis of mixed plastic waste, or biomass, or a combination thereof. Embodiments include methods of forming a thermal protective coating containing char particles. One such method includes the steps of selecting a coating composition containing a solvent, a binder, and char particles, applying the coating composition to a surface, and drying the coating composition to form a thermal protective coating on the surface. The method can further include the step of processing of mixed plastic waste, or biomass, or a combination thereof to produce a pyoil and the char particles. The method can further include the step of supplying the char particles to a milling process to produce char particles of a predetermined size. The predetermined size may be less than about 20 pm in size. The thermal protective coating on the surface may have a thickness ranging from about 100 pm to about 10 mm. The thermal protective coating on the surface may have a thickness ranging from about 10 mm to about 5 cm. In certain embodiments, the thermal conductivity of the surface decreases by about twenty percent or by about forty percent.

[0005] The details of one or more embodiments are set forth in the description below. Other features, objects, and advantages of the embodiments will be apparent from the description and the claims.Detailed Description

[0006] Char is a waste product from pyrolysis of biomass or mixed plastic waste or a combination thereof. One of the common sources of char is from a fast pyrolysis process. In this process, mixed plastic waste, or biomass, or a combination thereof is processed to produce pyoil and char. Char has varying ash content dependent on the feedstock. Further processing of char isexpensive and occurs either via incineration or landfilling. These processes are not environmentally friendly or sustainable processes. Therefore, an alternative use of the char is relevant to economics and environmental, social, and governance (ESG) characteristics of a pyrolysis plant. Embodiments described herein include coating compositions containing char. The thermal properties of char are harnessed when char is used to increase the insulative properties of a coating. A coating is a composition applied to a surface of an article to deliver a specific performance. Examples of the performance of a coating composition include color retention, flexibility and elasticity, insulation, waterproofing, water- shedding, permeability, corrosion containment and prevention, and anti-microbial defense. Provided here are coating compositions that deliver substantial thermal insulation.

[0007] Insulating coatings are normally produced by using aerogel as an insulating film. Aerogel is however relatively expensive. Provided here are coating compositions containing char as a filler to provide thermal insulation properties to the coating.

[0008] Embodiments include a coating composition containing a solvent, a binder, and char particles. In certain embodiments, the char particles are a byproduct of processing of mixed plastic waste, or biomass, or a combination thereof. Char has insulating properties. For example, the specific heat capacity at 20 degrees centigrade (°C) is about 1.39 and the specific heat capacity at 40 °C is about 1.75 when tested under the International Organization for Standardization (ISO) 11357-4 method. This standard specifies methods for determining the specific heat capacity of plastics by differential scanning calorimetry. Specific heat capacity is the quantity of heat needed to raise the temperature per unit mass, and usually measured as the heat in Joules needed to raise the temperature of 1 gram of sample by 1 degree Celsius. There is about a 40% reduction in thermal conductivity of certain products like concrete at 5% char addition.

[0009] Using char in coating compositions can keep the heat contained within a process equipment and improves energy efficiency. Coating compositions containing char can be used as architectural coatings, which is traditionally known as paint. These paint products are used to increase insulation and protect interior and exterior surfaces of residential, commercial, institutional, and industrial buildings. Coating compositions containing char can be used as industrial coatings to maintain the thermal functionality of manufactured products, such as processing equipment, tanks, reservoirs, heat exchangers, and pipelines. Coating compositions containing char can be used as special purpose coatings, such as an insulating coating. These coating compositions can be applied to machinery and equipment in plants and facilities, such as drying ovens, storage vessels, ductwork, boilers, sterilizers, pressure valves, and process equipment. Coating compositions containing char can include polyurethane coatings, epoxy coatings, alkyd coatings, zinc-rich coatings, polysiloxane coatings, acrylic coatings, or metalized coatings. Certain applications may require multiple layers of coatings, such as a layer of primer, a layer of coating containing char, and then a sealant. Coating compositions containing char can provide one or more advantages, such as savings of energy consumed to maintain temperature or energy efficiency of equipment coated with char containing insulating compositions. These coating compositions can be applied inside or outside to the machinery and equipment in plants and facilities. Furthermore, insulating coatings can protect operators from any accidental exposure to high temperatures.

[0010] Embodiments include methods of forming a thermal protective coating. One such method includes selecting a coating composition containing a solvent, a binder, and char particles, applying the coating composition to a surface, and drying the coating composition to form a thermal protective coating on the surface. The method further includes processing of mixed plasticwaste, or biomass, or a combination thereof to produce a pyoil and the char particles. The method further includes supplying the char particles to a milling process to produce char particles of a predetermined size. The predetermined size may be less than about 25 pm in size. The predetermined size may be less than about 20 pm in size. The predetermined size may be less than about 15 pm in size. The predetermined size may be less than about 10 pm in size. The thermal protective coating on the surface may have a thickness ranging from about 100 pm to about 10 mm. The thermal protective coating on the surface may have a thickness ranging from about 10 mm to about 5 cm. In certain embodiments, the thermal conductivity of the surface decreases by about twenty percent or by about forty percent. In certain embodiments, the thermal conductivity of the surface decreases by about ten percent. In certain embodiments, the thermal conductivity of the surface decreases by about fifteen percent. In certain embodiments, the thermal conductivity of the surface decreases by about twenty percent. In certain embodiments, the thermal conductivity of the surface decreases by about thirty percent. In certain embodiments, the thermal conductivity of the surface decreases by about forty percent.

[0011] In an embodiment, a mixed plastic waste feed containing a plurality of plastic polymers is supplied to a depolymerization unit. This unit is operated at a temperature and a residence time sufficient to at least partially depolymerize the plurality of plastic polymers in the mixed plastic waste feed to produce a molten oligomers product stream, char, vapors, and a gas stream containing volatile hydrocarbons. In certain embodiments, the char particles are a byproduct of fast pyrolysis of mixed plastic waste, or biomass, or a combination thereof. Fast pyrolysis of such feedstock is carried out at an operating temperature ranging from 500 °C to 700 °C.

[0012] Char is present in the molten oligomers product stream is removed before the molten oligomers product stream is supplied to a hydrocarbon processing unit to produce a high valuechemical (HVC) product. The hydrocarbon stream is also supplied to a hydrocarbon processing unit to produce a HVC product. The hydrogen-lean hydrocarbon stream can be one or more of an atmospheric residue, a vacuum residue, a straight run vacuum gas oil, or a cracked vacuum gas oil. The char-depleted molten oligomers product stream and the hydrogen-lean hydrocarbon stream can be mixed prior to being supplied to the hydrocarbon processing unit. The char may be removed from the molten oligomers product stream in a batch mode at the completion of each pyrolysis cycle. In certain embodiments, the char can be removed in a continuous mode from the molten oligomers product stream by continuous separation process, such as cyclone separation or continuous filtration.

[0013] The char can then be processed to remove moisture and produce an inert char product. In some examples, this inert char may be supplied to a milling process to produce char of certain particle size range. Char of a predetermined size range may then be supplied to the manufacturing process for the coating compositions. In some examples, this inert char may be cooled before being supplied to the manufacturing process for the coating compositions. In some examples, this inert char may be cooled before being supplied to a milling process to produce char of certain particle size range. Milling or grinding the char to a particular size range can include iterative steps of grinding to achieve a particular particle size range , followed by size exclusion to remove the larger particles. In certain embodiments, the method includes removal of metals from the milled char particles. A chemical leaching process can be used to remove the metals from the char particles. In certain embodiments, the method includes a functionalization process to remove amorphous impurities from the char particles.

[0014] In some examples, the method includes grinding particles to less than about 500 nanometers (nm) in size, less than about 400 nm in size, less than about 300 nm in size, less thanabout 200 nm in size, and less than about 100 nm in size. In some examples, the method includes grinding particles to a size ranging from about 100 nm to about 200 nm, from about 50 nm to about 150 nm, from about 10 nm to about 75 nm, or from about 10 nm to about 50 nm. In some examples, the method includes grinding particles to less than about 20 pm in size, less than about 10 pm in size, less than about 5 pm in size, and less than about 2 pm in size.

[0015] Char is introduced into coating compositions as a filler to enhance or modify its properties. In certain examples, the char particles are substantially insoluble in the application medium and can increase or influence the thermal insulation properties. The coating compositions containing char may be transferred onto a target surface to produce a coat of certain thickness. In some examples, the coating compositions containing char are applied using a sprayer. The coating composition is allowed to adhere to the target surface and then set or cure to form the coating. The thickness of the coating can range from about 100 pm to about 10 mm. The thickness of the coating can range from about 10 mm to about 5 cm. In certain examples, the coating compositions containing char may be transferred onto a target surface to produce a coat of uniform thickness. The coating can include a base material and a coating containing char formed on a surface of the base material.

[0016] When ranges are disclosed herein, ranges from any lower limit may be combined with any upper limit to recite a range not explicitly recited, as well as, ranges from any lower limit may be combined with any other lower limit to recite a range not explicitly recited, in the same way, ranges from any upper limit may be combined with any other upper limit to recite a range not explicitly recited. Additionally, reference to values stated in ranges includes each and every value within that range, even though not explicitly recited. Thus, every point or individual value mayserve as its own lower or upper limit combined with any other point or individual value or any other lower or upper limit, to recite a range not explicitly recited.

[0017] Other objects, features and advantages of the disclosure will become apparent from the foregoing drawings, detailed description, and examples. These drawings, detailed description, and examples, while indicating specific embodiments of the disclosure, are given by way of illustration only and are not meant to be limiting. In further embodiments, features from specific embodiments may be combined with features from other embodiments. For example, features from one embodiment may be combined with features from any of the other embodiments. In further embodiments, additional features may be added to the specific embodiments described herein. It should be understood that although the disclosure contains certain aspects, embodiments, and optional features, modification, improvement, or variation of such aspects, embodiments, and optional features can be resorted to by those skilled in the art, and that such modification, improvement, or variation is considered to be within the scope of this disclosure.

Claims

ClaimsWhat is claimed is:

1. A coating composition comprising a solvent, a binder, and char particles.

2. The coating composition of claim 1 , wherein the char particles are a byproduct of processing of mixed plastic waste.

3. The coating composition of claim 1, wherein the char particles are a byproduct of processing of biomass.

4. The coating composition of claim 1, wherein the char particles are a byproduct of fast pyrolysis of mixed plastic waste, or biomass, or a combination thereof.

5. The coating composition of claim 1, wherein the char particles are less than 20 pm in size.

6. The coating composition of claim 1, wherein the char particles are less than 10 pm in size.

7. A method of forming a thermal protective coating, the method comprising: selecting a coating composition containing a solvent, a binder, and char particles; applying the coating composition to a surface; and drying the coating composition to form a thermal protective coating on the surface.

8. The method of claim 7, further comprising: processing of mixed plastic waste, or biomass, or a combination thereof to produce a pyoil and the char particles.

9. The method of claim 7, further comprising: supplying the char particles to a milling process to produce char particles of a predetermined size.

10. The method of claim 9, wherein the predetermined size is less than 20 pm in size.

11. The method of claim 9, wherein the predetermined size is less than 10 pm in size.

12. The method of claim 7, wherein the thermal protective coating on the surface has a thickness ranging from 100 pm to 10 mm.

13. The method of claim 7, wherein the thermal protective coating on the surface has a thickness ranging from 10 mm to 5 cm.

14. The method of claim 7, wherein thermal conductivity of the surface decreases by about twenty percent upon forming the thermal protective coating.

15. The method of claim 7, wherein thermal conductivity of the surface decreases by about forty percent upon forming the thermal protective coating.