FR3108163A1 - Method and Device for supplying a gaseous fuel boiler - Google Patents

Abstract

The present invention relates to a device (1) for regulating the proportion of a gaseous mixture comprising natural gas including methane CH4 and hydrogen H2 for supplying a gaseous fuel boiler comprising: a first conduit (2) having a first end (21) and a second end (22), said first conduit (2) comprising natural gas comprising CH4, a second conduit (3) having a first end (31) and a second end (32), said second conduit (3) comprising H2, said second end (32) of the second conduit (3) being connected to the second end (22) of the first conduit (2), a proportional regulator 4) connected to the first conduit (2) to measure a first pressure P1 of the natural gas and connected to the second conduit (3) for measuring a second pressure P2 of the H2 and for regulating the volume flow rate of H2 in the second conduit (3) and a fuel boiler gas comprising a burner and being connected to the second end (22) of the first conduit (2). The invention also relates to a method for regulating the proportion of a gas mixture comprising a natural gas including methane CH4 and hydrogen H2 to feed a gaseous fuel boiler. Figure 1

Description

Method and device for supplying a gaseous fuel boiler

The present invention relates to a method and a device for supplying a gaseous fuel boiler. The present invention is particularly suitable for an urban gas distribution network.

The development of alternative energy sources has accelerated in recent decades with the aim of reducing carbon dioxide CO ₂ emissions and dependence on fossil fuels. These alternative energy sources include photovoltaic cells and wind turbines, which produce electrical energy without any direct emissions.

In the field of thermal energy, in particular heating, it is known to use natural gas, comprising the vast majority of methane, to supply a gaseous fuel boiler. This type of boiler is also used on a large scale, in particular in a factory or as central heating in buildings. However, the use of natural gas involves the production of CO ₂ .

To reduce CO ₂ emissions, it is known to use biomethane as an energy source. Biomethane is a renewable gas produced from waste from the agro-food industry, collective catering, agricultural and household waste, or sludge from wastewater treatment plants. It can be injected into the natural gas distribution network. It can in particular be used in a heating or urban hot water production network.

However, biomethane alone does not significantly reduce carbon dioxide emissions. Indeed, biomethane is energy poor, requiring a significant consumption of this gas which contains carbon. In addition, current production methods mainly include agricultural or transport activities that generate CO ₂ .

There therefore remains a need to provide a means making it possible to supply a boiler with gaseous fuels while reducing CO ₂ emissions, easily adaptable to an industrial scale and inexpensive.

The present invention relates to a device for regulating the proportion of a gas mixture comprising a natural gas including methane CH ₄ and hydrogen H ₂ to supply a gaseous fuel boiler comprising:

• a first conduit having a first end and a second end, said first conduit comprising the natural gas comprising CH ₄ ,
• a second conduit having a first end and a second end, said second conduit comprising H ₂ , said second end of the second conduit being connected to the second end of the first conduit,
• a proportional regulator connected to the first conduit to measure a first pressure P ₁ of the natural gas and connected to the second conduit to measure a second pressure P ₂ of the H ₂ and to regulate the volume flow rate of H ₂ in the second conduit and
• a gaseous fuel boiler comprising a burner and being connected to the second end of the first conduit.

Without wishing to be bound by a theory, it seems that the device according to the invention makes it possible to significantly reduce CO ₂ emissions by adding dihydrogen to the gaseous mixture. In addition, the device according to the invention makes it possible to easily regulate the proportion of H2 in the gas mixture. Finally, the device according to the invention is inexpensive and is easy to implement on an industrial scale.

In one embodiment, the proportional regulator is a pneumatic regulator.

In one embodiment, the first ends of the first and second conduits comprise, independently of each other, at least one valve. In this embodiment, the volume flow rates of H ₂ and natural gas can easily be regulated.

In one embodiment, the first conduit comprises a gas block of the burner of the boiler. In this embodiment, the burner gas block is used to control the natural gas supply to the boiler burner. The gas unit is for example a quick-opening and closing solenoid valve. In the event of a fault on the boiler, the gas block allows the natural gas supply to be cut off.

In one embodiment, the second conduit includes a solenoid valve. In this embodiment, the solenoid valve makes it possible to control the supply of H ₂ .

For example, the solenoid valve is connected to a control means. In this embodiment, the control means acts on the solenoid valve.

In one embodiment, the second conduit comprises a mechanical regulating valve with which the proportional regulator regulates the volume flow of H ₂ .

In one embodiment, the first and second conduits include a check valve. In one embodiment, the boiler is a condensing boiler.

The invention also relates to a method for regulating the proportion of a gaseous mixture comprising a natural gas including methane CH ₄ and hydrogen H ₂ to supply a gaseous fuel boiler with the device according to the invention comprising:

1. The supply of natural gas including methane CH ₄ in a first pipe and the supply of hydrogen in a second pipe,
2. The measurement of a first pressure P ₁ of the natural gas and of a second pressure P ₂ of the H ₂ by means of a proportional regulator,
3. The regulation of the volume flow of H ₂ with the proportional regulator acting on a mechanical regulation valve present in the second pipe.

The process according to the invention makes it possible to easily mix H ₂ and natural gas. Unlike the regulators of the prior art, the proportional regulator according to the invention makes it possible to measure two pressures, P ₁ and P ₂ , and to directly regulate the flow of hydrogen in the second conduit according to the pressures P ₁ and P ₂ measured. Indeed, the pressure being proportional to the volume flow, the controller can easily convert a pressure value into a volume flow and vice versa.

For example, H ₂ can be produced by electrolysis of water in the presence of electrical energy.

In one embodiment, before step A), in a selection step, the pressures P ₁ and P ₂ are selected.

In one embodiment, in step A), the percentage of H ₂ in the gas mixture is between 1 and 70 mol%. In this embodiment, it seems that the hydrogen contents make it possible to significantly reduce CO ₂ emissions while maintaining good performance for supplying the gaseous fuel boiler.

In one embodiment, in step A), the percentage of natural gas in the gas mixture is between 30 and 99 mol%.

In one embodiment, in step A), the natural gas further comprises at least one element chosen from: an alkane other than methane, carbon dioxide, nitrogen, hydrogen sulphide and 'helium. For example, the alkane different from methane is chosen from: propane or butane.

In one embodiment, in step A), the first pressure P ₁ of the natural gas is between 1 and 50 millibars, preferably 10 and 30 millibars and for example around 20 millibars.

In one embodiment, in step A), the second pressure P ₂ is between 1 and 50 millibars, preferably 10 and 30 millibars and for example around 20 or 22 millibars.

In one embodiment, in step B), the measurements of P ₁ and P ₂ are carried out periodically or continuously.

In one embodiment, in step C), when P ₁ and/or P ₂ is (are) below or above a pressure threshold value, the proportional regulator acts on the mechanical regulating valve to regulate the volume flow of H ₂ in the second conduit.

In one embodiment, when the burner of the boiler stops, a control means acts on a solenoid valve present in the second pipe to block the supply of H ₂ and a gas block of the burner of my boiler blocks the supply of gas natural. For example, the boiler burner can shut down when a fault occurs in the boiler. In this case, the mechanical regulation valve of the flow in H ₂ closes, P ₂ before zero.

Other aspects, objects, advantages and characteristics of the invention will appear better on reading the following detailed description of preferred embodiments thereof, given by way of non-limiting example, and made with reference to the appended drawings. on which ones:

illustrates a diagram of an example of a device according to the invention.

Figure 1 illustrates a device 1 comprising a first conduit 2 having a first end 21 and a second end 22, said first conduit 2 comprising natural gas including for example predominantly CH ₄ and a minority of nitrogen. Device 1 also comprises a second conduit 3 having a first end 31 and a second end 32, said second conduit 32 comprising H ₂ . The second end 32 of the second conduit 3 is connected to the second end 22 of the first conduit 2.

The gas mixture can take place at the level of the second end 22 of the first conduit 2 so as to supply a gaseous fuel boiler (not shown) comprising a burner (not shown).

In this example, a pneumatic proportional regulator 4 is connected to the first conduit 2 to measure a first pressure P ₁ of the natural gas and connected to the second conduit 3 to measure a second pressure P ₂ of the H ₂ and to regulate the volume flow rate of H ₂ in the second conduit 3.

Furthermore, the first duct 2 may comprise a gas block for the burner 23 of the boiler which makes it possible to control the supply of natural gas. For example, the gas block is located at the level of the first end 21 of the first pipe 2.

The second pipe 3 can comprise a solenoid valve 33 which makes it possible to control the supply of H ₂ . In this example, the solenoid valve is connected to a control means (not shown) which controls the solenoid valve 33.

The second pipe 3 can also comprise a mechanical regulating valve 34 with which the proportional regulator 4 regulates the volume flow rate of H ₂ .

The device may also include non-return valves 24, 35 located in the first and second ducts 2, 3. The non-return valves allow the circulation of gases in one direction and block the circulation of gases in the opposite direction.

With the device according to the invention, it is possible to select pressure threshold values P ₁ and P ₂ such that the molar concentration of H ₂ in the mixture is for example approximately 37% by volume. For example, the threshold value of P ₁ is 18 Millibars and the threshold value of P ₂ is 20 Millibars.

In a step A), the first conduit 2 is supplied with natural gas and the second conduit 3 is supplied with H ₂ .

In a step B), periodic measurements of P ₁ and P ₂ are carried out by means of the proportional regulator 4. For example, the measurement is carried out every hour.

In a step C), for example, when P ₁ and/or P ₂ is (are) below or above the threshold value as predefined above, the proportional regulator 4 acts on the mechanical regulation valve 34 to regulate the volume flow of H ₂ in the second conduit.

For example, when P ₁ is above the threshold value, the regulator 4 acts on the mechanical regulation valve 34 to increase the volume flow rate of H ₂ , increase P ₂ and thus to increase the molar percentage of H ₂ in the gas mixture.

For example, when P ₂ is above the threshold value, the regulator 4 acts on the mechanical regulation valve 34 to decrease the volume flow rate of H ₂ , decrease P ₁ and thus to decrease the molar percentage of H ₂ in the gas mixture.

The device and the method according to the invention make it possible to optimize the regulation of the proportion of the gaseous mixture comprising H ₂ and a natural gas comprising at least CH ₄ . The device and the method according to the invention are easy to implement on a large scale, in particular for an urban gas distribution network. Finally, they significantly reduce CO ₂ emissions.

Claims (20)

Device (1) for regulating the proportion of a gas mixture comprising a natural gas including methane CH₄and hydrogen H₂for supplying a gaseous fuel boiler comprising:

• a first conduit (2) having a first end (21) and a second end (22), said first conduit (2) comprising natural gas comprising CH ₄ ,
• a second conduit (3) having a first end (31) and a second end (32), said second conduit (3) comprising H ₂ , said second end (32) of the second conduit (3) being connected to the second end ( 22) of the first duct (2),
• a proportional regulator 4) connected to the first conduit (2) to measure a first pressure P ₁ of the natural gas and connected to the second conduit (3) to measure a second pressure P ₂ of the H ₂ and to regulate the volume flow rate of H ₂ in the second pipe (3) and
• a gaseous fuel boiler comprising a burner and being connected to the second end (22) of the first conduit (2).

Device according to Claim 1, in which the proportional regulator (4) is a pneumatic regulator. Device according to Claim 1 or 2, in which the first ends (21, 31) of the first (2) and second (3) ducts comprise, independently of each other, at least one valve. Device according to claim 3, the first pipe (2) comprises a gas unit (23) of the burner of the boiler. Device according to claim 3 or 4, the second conduit (3) comprises a solenoid valve (33). Device according to Claim 5, in which the solenoid valve (33) is connected to a control means. Device according to at least one of Claims 3 to 6, in which the second conduit (3) comprises a mechanical regulating valve (34) with which the proportional controller (4) regulates the volume flow of H ₂ . Device according to any one of Claims 1 to 7, in which the first (2) and second (3) conduits comprise a non-return valve (24, 35). Device according to any one of claims 1 to 8, in which the boiler is a condensing boiler. Method for regulating the proportion of a gas mixture comprising a natural gas including methane CH₄and hydrogen H₂for supplying a gaseous fuel boiler with the device according to any one of claims 1 to 8 comprising:

1. The supply of natural gas including methane CH ₄ in a first pipe (2) and the supply of hydrogen in a second pipe (3),
2. The measurement of a first pressure P ₁ of the natural gas and of a second pressure P ₂ of the H ₂ by means of a proportional regulator (4),
3. The regulation of the volume flow of H ₂ with the proportional regulator (4) acting on a mechanical regulation valve (34) present in the second pipe (3).

Method according to Claim 10, in which before step A), in a selection step, threshold values of the pressures P ₁ and P ₂ are selected. Process according to Claim 10 or 11, in which in stage A), the percentage of H ₂ in the gaseous mixture is between 1 and 70% in mole. Process according to any one of Claims 10 to 12, in which in stage A), the percentage of natural gas in the gaseous mixture is between 30 and 99% in mole. Process according to any one of Claims 10 to 13, in which in step A), the natural gas also comprises at least one element chosen from: an alkane other than methane, carbon dioxide, nitrogen, hydrogen sulfide and helium. Process according to Claim 14, in which the alkane other than methane is chosen from: propane or butane. Process according to any one of Claims 10 to 15, in which in step A), the first pressure P ₁ of the natural gas is 1 and 50 milibars. Process according to any one of Claims 10 to 16, in which in step A), the second pressure P ₂ is between 1 and 50 millibars. Method according to any one of Claims 10 to 17, in which in step B), the measurements of P ₁ and P ₂ are carried out periodically or continuously. Method according to any one of Claims 10 to 18, in which in step C), when P ₁ and/or P ₂ is (are) below or above a pressure threshold value, the regulator proportional (4) acts on the mechanical control valve (34) to regulate the volume flow of H ₂ in the second conduit (31). Method according to any one of claims 10 to 19, when the burner of the boiler stops, a control means acts on a solenoid valve (33) present in the second conduit (3) to block the supply of H ₂ and a gas block (23) of the boiler burner blocks the supply of natural gas.