US-12618558-B2 - Methods for operating a heating device

Abstract

Systems and methods for operating a heating device are disclosed. An oxygen containing stream is first processed to produce an oxygen stream that comprises more than 25 vol. % oxygen. The oxygen stream is then mixed with an air stream to produce a combustion gas stream comprising 21.5 to 27 vol. % oxygen. A fuel is combusted in the combustion gas stream to provide heat for a heating device.

Inventors

• Ananth SHARMA

Assignees

• SABIC GLOBAL TECHNOLOGIES B.V.

Dates

Publication Date

20260505

Application Date

20211118

Claims (8)

1. 1 . A method of operating a heating device, the method comprising: flowing a first air stream through one or more oxygen separation membrane modules disposed at a first inlet of the heating device to produce an oxygen enriched stream; flowing an additional air stream through a first inlet of the heating device such that the additional air stream and the oxygen stream form a first combustion gas stream; flowing a second air stream and the oxygen enriched stream into the heating device counter-currently to each other such that countercurrent sweep of air across a permeate side of the oxygen separation membrane modules is generated; mixing the second air stream mixes with the first combustion gas stream to produce an oxygen enriched combustion gas stream; and combusting a fuel in the oxygen enriched combustion gas stream in the heating device to produce heat.
2. 2 . The method of claim 1 , wherein the fuel includes CH 4 , H 2 , propane, ethane, or combinations thereof.
3. 3 . The method of claim 1 , wherein the countercurrent sweep is configured to reduce energy consumption for separating oxygen.
4. 4 . The method of claim 3 , wherein the fuel includes CH 4 , H 2 , propane, ethane, or combinations thereof.
5. 5 . The method of claim 1 , wherein the oxygen enriched combustion gas stream comprises 21.5 to 27 vol. % O 2 .
6. 6 . The method of claim 5 , wherein the fuel includes CH 4 , H 2 , propane, ethane, or combinations thereof.
7. 7 . The method of claim 1 , wherein the countercurrent sweep is configured to reduce energy consumption for separating oxygen.
8. 8 . The method of claim 7 , wherein the fuel includes CH 4 , H 2 , propane, ethane, or combinations thereof.

Description

CROSS REFERENCE TO RELATED APPLICATIONS This application is a national phase under 35 U.S.C. § 371 of International Application No. PCT/IB2021/060712, filed Nov. 18, 2021, which claims the benefit of priority to U.S. Provisional Patent Application No. 63/128,793, filed Dec. 21, 2020, the entire contents of each of which are hereby incorporated by reference in their entirety. FIELD OF INVENTION The present invention generally relates to systems and methods for operating heating devices. More specifically, the present invention relates to systems and methods for producing oxygen enriched combustion gas used for combusting fuels in heating devices. BACKGROUND OF THE INVENTION Heating is one of the most important processes in the chemical processing industry. Generally, to provide heat for chemical production processes, a fuel is combusted in air in a heating device (e.g., furnace, boiler, and heat exchanger). However, many chemical production processes, including steam cracking, are conducted at high operating temperatures, which requires the combustion process to be highly intense. The current methods of combusting fuel in air have limitations with respect to providing sufficient heat for chemical production processes, resulting in limited chemical production efficiency. Although the capacity of most heaters can be increased by simply firing hard, i.e., pushing in more fuel, the requirement for combustion air subsequently increases. The furnace can reach one or more of the following constraints including (1) mechanical flow limitation on process side like peak velocity; (2) limit of fuel gas header pressure; (3) limit of combustion air flow capacity. This results in furnace becoming the limiting equipment in further increasing the plant capacity. Various options can be explored to address the furnace capacity limitation, which may include installing a new furnace, upgrading design of furnace, burners or a combination, use of oxy-fuel combustion, etc. However, all these options are highly capital intensive and may be cost inhibitive. For pure O2 combustion, the main challenge includes availability and cost of O2 and furnace and burner modifications costs. An alternative in cases where small or moderate levels of production increase is desired is to use O2 enriched combustion instead of pure O2 combustion. Overall, while the methods of operating a heating device exist, the need for improvements in this field persists in light of the aforementioned drawback with conventional methods. BRIEF SUMMARY OF THE INVENTION A solution to at least the above-mentioned problem associated with the methods of operating a heating device has been discovered. The solution resides in a method of operating a heating device comprising using membrane based separation modules to produce an oxygen enriched air (>21 vol. % O2) as a combustion gas and combusting a fuel in the combustion gas. This can be beneficial for at least increasing energy efficiency for the fuel compared to conventional methods. Additionally, the disclosed method can further include flowing a first air stream through a membrane module and flowing a second air stream counter-currently to the first air stream through a separate air inlet to generate a countercurrent sweep of air across a permeate side of the membrane module, thereby improving energy efficiency of the membrane separation process. Furthermore, the disclosed method can include using a membrane separation unit installed at the inlet of the heating device, thereby eliminating the capital expenditure for exhaust fan, air blower, and ducting work. Furthermore, the disclosed method may include injecting oxygen enriched air upstream of the heating device (e.g., steam cracking furnace) via diffusors, resulting in improved mixing efficiency of oxygen and the fuel, compared to conventional methods. Therefore, the disclosed systems and methods of the present invention provide a technical solution to the problem associated with the conventional systems and methods for operating a heating device. Embodiments of the invention include a method of operating a heating device. The method comprises flowing a first stream comprising oxygen through one or more oxygen separation membrane modules at a first inlet of the heating device to produce an oxygen enriched stream. The method comprises flowing a second stream comprising and the oxygen stream into the heating device counter-currently to each other such that the second stream mixes with the oxygen stream to produce an oxygen enriched combustion gas stream. The method further still comprises combusting a fuel in the oxygen enriched combustion gas stream in the heating device to produce heat. Embodiments of the invention include a method of operating a heating device. The method comprises flowing a first air stream through one or more oxygen separation membrane modules disposed at a first inlet of the heating device to produce an oxygen enriched air stream. The method com