METHOD AND APPARATUS FOR IMPROVING A REFORMING PROCESS BY USING RENEWABLE ELECTRICAL ENERGY AS A HEATING INPUT TO THE REFORMING PROCESS

Abstract

A method for improving a reforming process by using renewable electrical energy as a heating input to the reforming process is provided. The method includes partially preheating combustion air using a first electrical heater, wherein the first electrical heater is configured to be supplied with the renewable electrical energy generated by a renewable source, wherein the first electrical heater is integrated in between a cold air preheater and a hot air preheater of a process plant that performs the reforming process; utilizing, by the first electrical heater, a bad based on an availability of the renewable electrical energy received from the renewable source; and providing, by the first electrical heater, the preheated combustion air at an outlet of the first electrical heater to a boiler of the process plant based on the bad utilized by the first electrical heater.

Claims

1. A method for improving a reforming process by using renewable electrical energy as a heating input to the reforming process, comprising: partially preheating combustion air using a first electrical heater, wherein the first electrical heater is configured to be supplied with the renewable electrical energy generated by a renewable source, wherein the first electrical heater is integrated in between a cold air preheater and a hot air preheater of a process plant that performs a reforming process; utilizing, by the first electrical heater, a load based on an availability of the renewable electrical energy received from the renewable source; and providing, by the first electrical heater, the preheated combustion air at an outlet of the first electrical heater to a boiler of the process plant based on the load utilized by the first electrical heater, wherein if the load utilized by the first electrical heater increases, a temperature of the preheated combustion air at the outlet of the first electrical heater and a load on the boiler are proportionally increased, thereby reducing fuel firing in the boiler and CO.sub.2 emissions.

2. The method according to claim 1, wherein the method includes preheating the combustion air to a temperature that is in a range of 250° C. to 500° C.

3. The method according to claim 1, wherein the method includes supplying the first electrical heater with the renewable electrical energy in a range of 0 watt to 3000 kilowatt.

4. The method according to claim 1, further comprising utilizing the preheated combustion air for firing in the reforming process if a reforming temperature is in a range of 750° C. to 950° C.

5. The method according claim 1, further comprising arranging for a steam to carbon ratio used to be in a range of 1.0 to 10.0.

6. The method according to claim 1, further comprising controlling, using a control unit, an outlet temperature of the preheated combustion air provided by the first electrical heater, wherein the control unit is configured to connect the load or the outlet temperature provided by the first electrical heater.

7. The method according to claim 1, further comprising utilizing, using a second electrical heater, a partial load away from the cold air preheater and the hot air preheater in a waste heat section to increase a preheat temperature of the combustion air at an inlet of the cold air preheater when the renewable electrical energy from the renewable source is supplied to the second electrical heater, thereby enabling a higher surface temperature of the cold air preheater to be achieved and avoiding corrosion resulting from a sulphur dew point.

8. The method according to claim 7, further comprising arranging for the load utilized by the second electrical heater to increase for each degree fall in the surface temperature of the cold air preheater.

9. The method according to claim 1, further comprising preheating the combustion air using steam before preheating using a flue gas, wherein the combustion air is heated using a third electrical heater that is supplied with the renewable electrical energy generated by the renewable source.

10. The method according to claim 1, further comprising generating the renewable electrical energy from a renewable energy source, wherein the renewable energy source includes at least one of wind energy, solar energy, hydroelectric source, or biomass source.

11. The method according to claim 9, wherein the method includes using ambient air in a temperature range of −10° C. to 20° C.

12. The method according to claim 9, wherein the method includes using a sulfur dew point of the flue gas for air preheating in a range of 80° C. to 110° C.

13. The method according to claim 9, wherein the flue gas from the air preheating is in a range of 120° C. to 160° C.

14. The method according to claim 1, further comprising arranging for the process plant to be a Steam Methane Reforming process plant, wherein the Steam Methane Reforming process plant is a part of a chemical plant producing hydrogen, methanol, ammonia, syngas or chemicals in downstream sections.

15. A method for improving a reforming process by integrating renewable electrical energy generation therewith, comprising: partially preheating combustion air using a first electrical heater that is supplied with renewable electrical energy generated by a renewable source, wherein the first electrical heater is integrated in between a cold air preheater and a hot air preheater of a process plant that performs the reforming process; utilizing, by using the first electrical heater, a load based on availability of the renewable electrical energy received from the renewable source; providing, by using the first electrical heater, the preheated combustion air at an outlet of the first electrical heater to a boiler of the process plant based on the load utilized by the first electrical heater, wherein if the load utilized by the first electrical heater increases, a temperature of the preheated combustion air at the outlet of the first electrical heater and a load on the boiler are proportionally increased, thereby reducing fuel firing in the boiler and CO.sub.2 emissions; and utilizing, by using a second electrical heater , a partial load that is located spatially away from the cold air preheater and the hot air preheater in a waste heat section to increase a preheat temperature of the combustion air at an inlet of the cold air preheater when the renewable electrical energy from the renewable source is supplied to the second electrical heater, thereby enabling a higher surface temperature of the cold air preheater and avoiding corrosion resulting from a Sulphur-dew point.

16. The method according to claim 15, further comprising controlling the surface temperature of the cold air preheater using a second control unit that controls the surface temperature of the cold air preheater based on the load utilized by the second electrical heater.

17. An apparatus for improving a reforming process by integrating renewable electrical energy therewith, comprising: a first electrical heater that is configured to partially preheat combustion air using the renewable electrical energy generated by a renewable source, wherein the first electrical heater is integrated in between a cold air preheater and a hot air preheater of a process plant that performs a reforming process; to utilize a load based on an availability of the renewable electrical energy received from the renewable source; and to provide the preheated combustion air at an outlet of the first electrical heater to a boiler of the process plant based on the load utilized by the first electrical heater, wherein if the load utilized by the first electrical heater increases, a temperature of the preheated combustion air at the outlet of the first electrical heater and a load on the boiler are proportionally increased, thereby reducing fuel firing in the boiler and CO.sub.2 emissions.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0030] The summary above, as well as the following detailed description of illustrative embodiments, is better understood when read in conjunction with the appended drawings. To illustrate the present disclosure, exemplary constructions of the disclosure are shown in the drawings. However, the present disclosure is not limited to specific methods and instrumentalities disclosed herein. Moreover, those in the art will understand that the drawings are not to scale. Wherever possible, the same elements have been indicated by identical numbers. Embodiments of the present disclosure will now be described, by way of example only, with reference to the following diagrams wherein:

[0031] FIG. 1 is a schematic illustration of an apparatus for improving a reforming process by integrating renewable electrical energy generation therewith according to an embodiment of the present disclosure;

[0032] FIG. 2 is a flowchart illustrating a method for improving a reforming process by using renewable electrical energy as a heating input to the reforming process according to an embodiment of the present disclosure; and

[0033] FIG. 3 is a flowchart illustrating a method for improving a reforming process by integrating renewable electrical energy generation therewith according to an embodiment of the present disclosure.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

[0034] The following detailed description illustrates embodiments of the present disclosure and ways in which they can be implemented. Although some modes of carrying out the present disclosure have been disclosed, those skilled in the art would recognize that other embodiments for carrying out or practicing the present disclosure are also possible.

[0035] According to a first aspect, the present disclosure provides a method for improving a reforming process by using renewable electrical energy as a heating input to the reforming process, wherein the method comprises: partially preheating combustion air using a first electrical heater, wherein the first electrical heater is configured to be supplied with the renewable electrical energy generated by a renewable source, wherein the first electrical heater is integrated in between a cold air preheater and a hot air preheater of a process plant that performs the reforming process; utilizing, by the first electrical heater, a load based on an availability of the renewable electrical energy received from the renewable source; and providing, by the first electrical heater, the preheated combustion air at an outlet of the first electrical heater to a boiler of the process plant based on the load utilized by the first electrical heater, wherein if the load utilized by the first electrical heater increases, a temperature of the preheated combustion air at the outlet of the first electrical heater and a load on the boiler are proportionally increased, thereby reducing fuel firing in the boiler and CO.sub.2 emissions.

[0036] The method for improving the reforming process by using the renewable electrical energy as the heating input to the reforming process according to the present disclosure is of advantage in that the method enables lower fuel firing, thereby reducing CO.sub.2 emissions and increasing a lifetime of the reforming tubes as it reduces metal temperature of reforming tubes in the process plant.

[0037] The method for improving the reforming process has less impact on the design of the process plant. Moreover, the method ensures seamless operation of the reforming process in the process plant with zero to peak renewable electricity input.

[0038] Optionally, an overall air preheat temperature at the outlet of the hot air preheater, going to burners of the process plant is constant. Optionally, if the hot air preheater utilizes less load, the load available on the boiler situated downstream in flue gas flow direction is high, thereby increasing steam production when the first electrical Heater is taking more load. Such an increase in steam production improves thermal efficiency and lowers operating expenditure (OpEx) of the reforming process.

[0039] For example, for applications where steam value is relatively high (say, more than ˜70% of fuel value), additional steam may be exported which means higher thermal efficiency and lower OpEx, and lower carbon footprint. For applications where steam value is relatively lower, additional steam can be used within the reforming process. More steam used for the reforming process may result in higher feed conversion. This results in reduced fuel firing and/or reduced feed and overall reduced CO.sub.2 emissions.

[0040] The fuel for firing may be natural gas, liquid hydrocarbon, coal, tar, petroleum coke, and naphtha.

[0041] Optionally, the method includes preheating the combustion air to a temperature that is in a range of 250° C. to 500° C.

[0042] Optionally, the method includes supplying the first electrical heater with the renewable electrical energy in a range of 0 watt (W) to 3000 kilowatt (kW).

[0043] Optionally, the method includes utilizing the preheated combustion air for firing in the reforming process if a reforming temperature is in a range of 750° C. to 950° C.

[0044] Optionally, the method includes arranging for a steam to carbon ratio used to be in a range of 1.0 to 10.0.

[0045] Optionally, the method further includes controlling, using a control unit, an outlet temperature of the preheated combustion air provided by the first electrical heater. The control unit is configured to connect the load or the outlet temperature provided by the first electrical heater.

[0046] For example, for each degree (or fraction of a degree) rise in the outlet temperature from the first electrical heater, fuel firing in the reforming process can be reduced accordingly. Optionally, each degree rise in the outlet temperature from the first electrical heater is calculated using a well-defined equation based on estimations/simulations of such scenarios.

[0047] Optionally, the method further includes utilizing, using a second electrical heater, a partial load away from the cold air preheater and the hot air preheater in a waste heat section to increase a preheat temperature of the combustion air at an inlet of the cold air preheater when the renewable electrical energy from the renewable source is supplied to the second electrical heater, thereby enabling a higher surface temperature of the cold air preheater and avoiding corrosion resulting from a sulphur dew point. Moreover, the method may enable more steam production to be achieved by using the second electrical heater.

[0048] Optionally, the second electrical heater is installed at a suction region of a combustion air fan.

[0049] Optionally, the method includes arranging for the load utilized by the second electrical heater to increase for each degree fall in the surface temperature of the cold air preheater. Optionally, each degree fall in the surface temperature of the cold air preheater is calculated using a well-defined equation based on estimations/simulations of such scenarios.

[0050] Optionally, the method includes preheating the combustion air using steam before preheating the combustion air using a flue gas. The combustion air is heated using a third electrical heater that is supplied with the renewable electrical energy generated by the renewable source.

[0051] Optionally, the method includes generating the renewable electrical energy from a renewable energy source. The renewable energy source includes at least one of wind energy, solar energy, hydroelectric source, or biomass source.

[0052] Optionally, the method includes using ambient air in a temperature range of −10° C. to 20° C.

[0053] Optionally, the method includes using a sulfur dew point of the flue gas for air preheating in a range of 80° C. to 110° C. Optionally, the flue gas from the air preheating is in a range of 120° C. to 160° C.

[0054] Optionally, the method includes arranging for the process plant to be a steam methane reforming (SMR) process plant. The steam methane reforming process plant is a part of a chemical plant producing hydrogen (H.sub.2), methanol, ammonia, syngas or chemicals in downstream sections

[0055] According to a second aspect, the present disclosure provides a method for improving a reforming process by integrating renewable electrical energy generation therewith, the method comprising: partially preheating combustion air using a first electrical heater that is supplied with renewable electrical energy generated by a renewable source, wherein the first electrical heater is integrated in between a cold air preheater and a hot air preheater of a process plant that performs the reforming process; utilizing, by using the first electrical heater, a load based on an availability of the renewable electrical energy received from the renewable source; providing, by using the first electrical heater, the preheated combustion air at an outlet of the first electrical heater to a boiler of the process plant based on the load utilized by the first electrical heater, wherein if the load utilized by the first electrical heater increases, a temperature of the preheated combustion air at the outlet of the first electrical heater and a load on the boiler are proportionally increased, thereby reducing fuel firing in the boiler and CO.sub.2 emissions; and utilizing, by using a second electrical heater, a partial load that is located spatially away from the cold air preheater and the hot air preheater in a waste heat section to increase a preheat temperature of the combustion air at an inlet of the cold air preheater when the renewable electrical energy from the renewable source is supplied to the second electrical heater, thereby enabling a higher surface temperature of the cold air preheater and avoiding corrosion resulting from a sulphur dew point.

[0056] The method for improving the reforming process by integrating the renewable electrical energy generation therewith according to the present disclosure is of advantage in that the method enables a lower fuel firing to be achieved, thereby reducing CO.sub.2 emissions and increasing lifetime of the reforming tubes as it reduces a metal temperature of reforming tubes in the process plant. The method further enables a higher surface temperature to be achieved in a cold end of the cold air preheater and avoids corrosion in the cold air preheater resulting from the sulphur dew point.

[0057] Optionally, the method includes controlling the surface temperature of the cold air preheater using a second control unit that controls the surface temperature of the cold air preheater based on the load utilized by the second electrical heater.

[0058] According to a third aspect, the present disclosure provides an apparatus for improving a reforming process by integrating renewable electrical energy therewith: wherein the apparatus comprises: a first electrical heater that is configured to partially preheat combustion air using the renewable electrical energy generated by a renewable source, wherein the first electrical heater is integrated in between a cold air preheater and a hot air preheater of a process plant that performs the reforming process; to utilize a load based on an availability of the renewable electrical energy received from the renewable source; and to provide the preheated combustion air at an outlet of the first electrical heater to a boiler of the process plant based on the load utilized by the first electrical heater, wherein if the load utilized by the first electrical heater increases, a temperature of the preheated combustion air at the outlet of the first electrical heater and a load on the boiler are proportionally increased, thereby reducing fuel firing in the boiler and CO.sub.2 emissions.

[0059] The apparatus for improving the reforming process by integrating renewable electrical energy therewith according to present disclosure lowers fuel firing, thereby reducing CO.sub.2 emissions and increasing lifetime of the reforming tubes as it reduces metal temperature of reforming tubes in the process plant. Moreover, the apparatus has less impact on design of the process plant and seamlessly operate with zero to peak renewable electricity input.

[0060] A table below includes an example of a green electricity integrated in an existing SMR process using the method of the present disclosure.

TABLE-US-00001 Existing Present Parameters approach apparatus H2 Production, Nm.sup.3/hr 56000 56000 Steam co-Production, kg/hr 0 0 S/C Ratio 3.05 3.05 Reforming temperature, ° C. 885 882 Flue Gas Temperature ex Reformer, ° C. 1051 1046 Air preheat Temperature, ° C. 450 450 Green Electricity input, kW (Note 1) 0 500 Internal Steam Production, kg/hr 50454 50808 SMR duty, MW 55.4 55.2 CO.sub.2 Emission from flue gas, Tons/hr 43.2 43.1 NG Feed + Fuel, Nm.sup.3/hr 20700 20664 NG feed, Nm.sup.3/hr 20120 20249 NG Fuel, Nm.sup.3/hr 579 415 Feed + Fuel saving, Nm.sup.3/hr — 36 Feed + Fuel saving, LHV basis, kW — 357 Feed + Fuel saving, % — 0.17%

[0061] Optionally, the method enables a saving of approximately 330 kW equivalent of supplementary fuel firing in SMR (e.g., Natural Gas (NG)) for 500 kW of renewable electrical energy, with an approximately 0.25% reduction in CO.sub.2 emission from the flue gas and also an increased reformer tube lifetime because of relatively less NG firing. Additionally, the method enables to reduce sulfur dew point under-run/corrosion problems in Cold Air Preheaters (APHs).

[0062] Optionally, a LP steam air preheater is replaced before the combustion air preheater, thereby enabling a minimum metal temperature in cold air preheater to be increased by 20° C., thereby eliminating sulfuric acid corrosion problem if sulfur is used as a fuel.

[0063] Embodiments of the present disclosure substantially eliminate or at least partially address the aforementioned technical drawbacks in existing technologies in improving reforming process by using renewable electrical energy as the heating input to the reforming process.

[0064] FIG. 1 is a schematic illustration of an apparatus 102 for improving a reforming process by integrating renewable electrical energy generation therewith according to an embodiment of the present disclosure. The apparatus 102 includes a first electrical heater 104, a cold air preheater 106, a hot air preheater 108 and a boiler 110. The first electrical heater 104 is configured to partially preheat combustion air using the renewable electrical energy generated by a renewable source. The first electrical heater 104 is integrated in between the cold air preheater 106 and the hot air preheater 108 of a process plant that performs the reforming process. The first electrical heater 104 is configured to utilize a load based on an availability of the renewable electrical energy received from the renewable source. The first electrical heater 104 is configured to provide the preheated combustion air at an outlet of the first electrical heater 104 to the boiler 110 of the process plant based on the load utilized by the first electrical heater 104. If the load utilized by the first electrical heater 104 increases, a temperature of the preheated combustion air at the outlet of the first electrical heater 104 and a load on the boiler 110 are proportionally increased, thereby reducing fuel firing in the boiler 110 and CO2 emissions.

[0065] Optionally, the apparatus 102 further includes a second electrical heater 112, a combustion air fan 114A, a flue gas fan 114B, and a flue gas stack 116. Optionally, the second electrical heater 112 utilizes a partial load that is located spatially away from the cold air preheater 106 and the hot air preheater 108 in a waste heat section to increase a preheat temperature of the combustion air at an inlet of the cold air preheater 106 when the renewable electrical energy from the renewable source is supplied to the second electrical heater 112, thereby enabling a higher surface temperature of the cold air preheater 106 and avoiding corrosion resulting from a sulphur dew point.

[0066] FIG. 2 is a flowchart illustrating a method for improving a reforming process by using renewable electrical energy as a heating input to the reforming process according to an embodiment of the present disclosure. At a step 202, combustion air is partially preheated using a first electrical heater. The first electrical heater is configured to be supplied with the renewable electrical energy generated by a renewable source. The first electrical heater is integrated in between a cold air preheater and a hot air preheater of a process plant that performs the reforming process. At a step 204, a load is utilized by the first electrical heater based on an availability of the renewable electrical energy received from the renewable source. At a step 206, the preheated combustion air is provided at an outlet of the first electrical heater, by the first electrical heater, to a boiler of the process plant based on the load utilized by the first electrical heater. If the load utilized by the first electrical heater increases, a temperature of the preheated combustion air at the outlet of the first electrical heater and a load on the boiler are proportionally increased, thereby reducing fuel firing in the boiler and CO.sub.2 emissions.

[0067] FIG. 3 is a flowchart illustrating a method for improving a reforming process by integrating renewable electrical energy generation therewith according to an embodiment of the present disclosure. At a step 302, combustion air is partially preheated using a first electrical heater that is supplied with renewable electrical energy generated by a renewable source. The first electrical heater is integrated in between a cold air preheater and a hot air preheater of a process plant that performs the reforming process. At a step 304, a load is utilized by the first electrical heater, based on availability of the renewable electrical energy received from the renewable source. At a step 306, the preheated combustion air is provided at an outlet of the first electrical heater, by using the first electrical heater, to a boiler of the process plant based on the load utilized by the first electrical heater. If the load utilized by the first electrical heater increases, a temperature of the preheated combustion air at the outlet of the first electrical heater and a load on the boiler are proportionally increased, thereby reducing fuel firing in the boiler and CO.sub.2 emissions. At a step 308, a partial load that is located spatially away from the cold air preheater and the hot air preheater in a waste heat section, is utilized by using a second electrical heater to increase a preheat temperature of the combustion air at an inlet of the cold air preheater when the renewable electrical energy from the renewable source is supplied to the second electrical heater, thereby enabling a higher surface temperature of the cold air preheater to be achieved and avoiding corrosion resulting from a Sulphur-dew point.

[0068] Modifications to embodiments of the present disclosure described in the foregoing are possible without departing from the scope of the present disclosure as defined by the accompanying claims. Expressions such as “including”, “comprising”, “incorporating”, “have”, “is” used to describe, and claim the present disclosure are intended to be construed in a non-exclusive manner, namely allowing for items, components or elements not explicitly described also to be present. Reference to the singular is also to be construed to relate to the plural.

LIST OF REFERENCE NUMERALS

[0069] 102—apparatus [0070] 104—first electrical heater [0071] 106—cold air preheater [0072] 108—hot air preheater [0073] 110—boiler [0074] 112—second electrical heater [0075] 114A—combustion air fan [0076] 114B—flue gas fan [0077] 116—flue gas stack