Device for connecting a production facility for non-fossil natural gas to a gas distribution network, in particular a public gas distribution network

Description

[0001] The invention firstly relates to a device for connecting a production facility for non-fossil natural gas to a gas distribution network, in particular a public gas distribution network, in which the supply of gas to the network is measured and monitored.

[0002] JP 57 200799 A discloses a technical solution for switching from a city gas supply to natural gas supply using a satellite supply system. A natural gas substituting the city gas is prepared from city gas and propane gas derived from a tank. The city gas is adjusted to a predetermined pressure by a compressor and a pressure adjuster sets the pressure of the propane gas. Then the components are premixed by a pre-mixer and subsequently re-mixed in an after-mixer prior to supply to the city gas supply area.

[0003] Currently, the processing of biological residual and waste materials in order to reduce the amount of residual and waste material which is ultimately to be discharged, for example to a dumping ground or an incineration plant, receives a lot of attention. Fermentation of manure from animals, such as cows, pigs and poultry, is one example of such processing which is being used in livestock breeding. Fermentation is also applied in water treatment plants, but in that case for sewage sludge. Such a process results in the formation of non-fossil gaseous fuel (also referred to as biogas below), which contains a significant amount of methane (compared to any heavier hydrocarbons which may be present). In some cases, this biogas is flared, in other cases it is consumed internally or used to generate electricity. Biogas can also be worked up to produce a non-fossil natural gas, that is to say a non-fossil gaseous fuel, which can be used as a substitute for fossil natural gas.

[0004] In the Netherlands, the public gas distribution network for natural gas consists of a nationwide high-pressure network with branch lines to regional and local distribution networks in which the pressure is lower (usually 8 bar or less). The network operator is responsible for the quality of the natural gas, both with regard to composition and with regard to heat content.

[0005] The present invention relates to the introduction of non-fossil natural gas into such a network, generally the local network which is at relatively low pressure. In connection with quality assurance, stringent requirements have to be imposed on the non-fossil natural gas which is to be introduced into the network. The composition and therefore the properties of the non-fossil natural gases can vary considerably, depending on the process which is used to process the biological residual and waste material, the starting material and the process conditions which are applied.

[0006] Thus, there is a demand for a connection between an arbitrary processing plant (which is also the production facility for non-fossil natural gas) and the public gas distribution network in which the introduction of non-fossil natural gas into the network is measured and monitored.

[0007] It is an object of the invention to satisfy this demand.

[0008] According to the invention, the device for connecting a production facility for non-fossil natural gas to a gas distribution network, in particular a public natural gas distribution network, comprises
a supply line for introducing non-fossil natural gas produced in said production facility, provided with at least one shut-off valve;
a return line for returning non-fossil natural gas which is flow-connected to said supply line via a shut-off valve;
a discharge line for discharging non-fossil natural gas which is flow-connected to said supply line via a shut-off valve;
pressure-reducing means for reducing the pressure of non-fossil natural gas produced in said production facility to a predetermined value;
a flow meter for measuring the flow rate of non-fossil natural gas;
a measuring device for measuring the caloric value of non-fossil natural gas or a characteristic related thereto at a location upstream of the shut-off valve in the supply line; an analyzing device for at least partially analyzing the composition of non-fossil natural gas at a location upstream of the shut-off valve in the supply line;
a control device for controlling the shut-off valve on the basis of the data provided by the measuring device and by the analyzing device.

[0009] The device according to the invention is an independent apparatus which can readily be placed between any production facility for non-fossil natural gas with its own process-specific process control unit and the public gas distribution network, and which can measure and monitor the quality and quantity of the non-fossil natural gas which is to be supplied to the gas distribution network depending on the production facility used, the specific process used, the process conditions and starting materials.

[0010] To this end, the device according to the invention comprises a supply line between the production facility and a shut-off valve. In this supply line, the gas produced in the production facility flows. The quality of the gas is measured in this line by means of gas-sampling devices using component analysis in the analyzing device and a determination of the caloric value or characteristic related thereto in said measuring device. There is usually only an upper limit with regard to the acceptable content of harmful or undesirable components in the gas to be supplied to the distribution network, whereas the caloric value usually has to be within a defined range having an upper limit and a lower limit. Generally, the complete composition of the non-fossil natural gas will be determined, although in most cases a more limited analysis of the hydrocarbons which are present (mainly methane) and carbon dioxide would suffice. The shut-off valve is operated on the basis of the measured values. If the gas is of the desired quality, it will flow to the distribution network via the pressure-reducing means and via the shut-off valve in the discharge line. The pressure-reducing means lower the pressure of the non-fossil natural gas produced to a desired value, typically to the pressure prevailing in the public network in question. If the gas does not meet the quality standards, it will flow into the return line. This return line may, for example, be connected to the production facility, so that the gas is returned to the process or part thererof, for example, only to any possible working-up steps. The return line may also end in a flare, where the gas which has been produced is burnt. The flow meter measures the volume of gas per unit time, which gas is introduced into the distribution network. As has already been mentioned, the control unit controls the shut-off valve, for example a three-way valve, on the basis of measured signals originating from the gas analyzer and the measuring device which are compared to predetermined values or ranges.

[0011] The measuring device is preferably a (certified) meter for determining the Wobbe index of the gas to be supplied to the distribution network. The Wobbe index is an indicator for the combustion energy of the gas. In the Netherlands, natural gas in the standard network has a Wobbe index of between 43.46 and 44.41, for example.

[0012] The gas-analysis device is preferably designed to analyze at least the CO₂, O₂ and H₂S content of the biogas. These are gases which are frequently found in biogas. These gases should only be present in the distribution network in limited amounts. In addition, the temperature, hydrocarbons (in particular methane) and relative humidity are advantageously determined as well.

[0013] Sampling, analysis and measurement are preferably carried out semi-continuously, it being possible for the periodicity of the analysis and of the measurement to differ with respect to one another.

[0014] Advantageously, the supply line, return line and discharge line are provided with gas-sampling devices which allow gas samples to be taken from these lines.

[0015] The control device preferably comprises a memory for storing data originating from the analysis device, measuring device and flow meter, which can be used later for verification and/or billing purposes. The memory can advantageously be accessed remotely, for example via a telephone line or in another telemetric way.

[0016] The invention also relates to an assembly comprising a production facility for producing non-fossil natural gas and the coupling device according to the invention.

[0017] The invention will be described in more detail below with reference to the attached figure, which diagrammatically shows an embodiment of a device according to the invention.

[0018] In this figure, a production facility for producing non-fossil natural gas from biological residual material, such as manure or sludge, is denoted by reference numeral 10. The regional distribution network which distributes natural gas to private and industrial users is denoted by reference numeral 12. A coupling device 14 according to the invention is situated between the production facility 10 and the network 12. The independent device 14 generally comprises a housing 16 inside which the various components are arranged. The device 14 comprises a supply line 18 which is coupled to the production device 10. A gas analyzer 20 for at least CO₂, O₂ and H₂S and a Wobbe index meter 22 are coupled to this supply line 18 upstream of a shut-off valve 24. Signals originating from the gas analyzer 20 and the meter 22 are processed by the control device 26 in order to control shut-off valve 24. The shut-off valve 24 connects the supply line 18 to either a discharge line 28 which is connected to the network 12 or to return line 30 which in this case is connected to the production device 10. Pressure-reducing means 38, for example a reduction valve, and a flow meter 32 are provided in the discharge line 28, the signals of which are transmitted to control device 26. This control device 26 comprises a memory 34 for storing data. As has been indicated above, these data can be passed on for billing purposes, for example by means of a communication means (not shown), such as a telephone, a computer, etc. Reference numeral 36 denotes the relevant sensors of the gas analyzer 20, Wobbe index meter 22 and flow meter 32.

Claims

1. Device (14) for connecting a production facility (10) for non-fossil natural gas to a gas distribution network (12), in particular a public gas distribution network, comprising
a supply line (18) for introducing non-fossil natural gas produced in said production facility (10), provided with at least one shut-off valve (24);
a return line (30) for returning non-fossil natural gas which is flow-connected to said supply line (18) via a shut-off valve (24);
a discharge line (28) for discharging non-fossil natural gas which is flow-connected to said supply line (18) via a shut-off valve (24);
pressure-reducing means (38) for reducing the pressure of non-fossil natural gas produced in said production facility to a predetermined value;
a flow meter (32) for measuring the flow rate of non-fossil natural gas;
a measuring device (22) for measuring the caloric value of non-fossil natural gas at a location upstream of the shut-off valve (24) in the supply line (18);
an analyzing device (20) for at least partially analyzing the composition of non-fossil natural gas at a location upstream of the shut-off valve (24) in the supply line (18);
a control device (26) for controlling the shut-off valve (24) on the basis of the data provided by the measuring device (32) and by the analyzing device (20).

2. Device according to claim 1, in which the shut-off valve (24) in the supply line (18) comprises a three-way valve.

3. Device according to claim 1 or 2, in which the measuring device (22) is a Wobbe index meter.

4. Device according to one of the preceding claims, in which the analyzing device (20) is designed to determine at least the CO₂, O₂ and H₂S contents.

5. Device according to one of the preceding claims, in which the analyzing device (20) is also connected to the return line (30).

6. Device according to one of the preceding claims, in which the supply line (18) is provided with gas-sampling devices (36) for taking a sample from the respective line.

7. Device according to one of the preceding claims, in which the control device is provided with a memory (34) for storing data from the measuring device and analyzing device.

8. Device according to claim 7, in which the memory (34) can be read remotely.

9. Device according to claim 7 or 8, in which the device is provided with telemetric facilities.

10. Assembly comprising a production facility (10) for producing non-fossil natural gas from biological residual material and a device (14) according to one of the preceding claims.

Ansprüche

1. Vorrichtung (14) zum Verbinden einer Produktionsanlage (10) für nicht-fossiles Erdgas mit einem Gasverteilungsnetzwerk, insbesondere mit einem öffentlichen Gasverteilungsnetzwerk, umfassend:

- eine Versorgungsleitung (18) zum Einleiten von in der Produktionsanlage hergestelltem nicht-fossilen Erdgas, die mit wenigstens einem Absperrventil (24) versehen ist;

- eine Rückleitung (30) zum Zurückleiten des nicht-fossilen Erdgases, die durchflussmäßig über ein Absperrventil (24) mit der Versorgungsleitung (18) verbunden ist;

- eine Ablassleitung (28) zum Ablassen des nicht-fossilen Erdgases, die über ein Absperrventil (24) durchflussmäßig mit der Versorgungsleitung (18) verbunden ist;

- eine Druckreduzierungseinrichtung (38) zum Reduzieren des Drucks des in der Produktionsanlage (10) hergestellten, nicht-fossilen Erdgases, auf einen vorbestimmten Wert;

- einen Durchflussmesser (32) zum Messen der Durchflussrate des nicht-fossilen Erdgases;

- eine Messvorrichtung (22) zum Messen des kalorischen Wertes des nicht-fossilen Erdgases stromaufwärts vom Absperrventil (24) in der Versorgungsleitung (18);

- eine Analysevorrichtung (20) zum wenigstens teilweisen Analysieren der Zusammensetzung des nicht-fossilen Erdgases stromaufwärts vom Absperrventil (24) in der Versorgungsleitung (18);

- eine Steuerungsvorrichtung (26) zum Steuern des Absperrventils (24) auf Basis der Daten, die von der Messvorrichtung (22) und der Analysevorrichtung (20) bereitgestellt werden.

2. Vorrichtung nach Anspruch 1, bei der das Absperrventil (24) in der Versorgungsleitung (18) ein Dreiwege-Ventil umfasst.

3. Vorrichtung nach Anspruch 1 oder 2, bei der die Messvorrichtung (22) ein Wobbe-Index-Messer ist.

4. Vorrichtung nach einem der vorstehenden Ansprüche, bei der die Analysevorrichtung (20) ausgelegt ist, um wenigstens den CO₂-, O₂- und H₂S-Gehalt zu bestimmen.

5. Vorrichtung nach einem der vorstehenden Ansprüche, bei der die Analysevorrichtung (20) auch mit der Rückleitung (30) verbunden ist.

6. Vorrichtung nach einem der vorstehenden Ansprüche, bei der die Versorgungsleitung (18) mit einer Vorrichtung zur Entnahme von Gasproben (36) zum Entnehmen von Gasproben aus der entsprechenden Leitung versehen ist.

7. Vorrichtung nach einem der vorstehenden Ansprüche, bei der die Steuerungsvorrichtung mit einem Speicher (34) zum Speichern von Daten von der Messvorrichtung und der Analysevorrichtung versehen ist.

8. Vorrichtung nach Anspruch 7, bei der der Speicher (34) ferngesteuert ausgelesen werden kann.

9. Vorrichtung nach Anspruch 7 oder 8, die weiter mit telemetrischen Einrichtungen versehen ist.

10. Anlage umfassend eine Produktionsanlage (10) für das Herstellen von nichtfossilem Erdgas aus biologischen Reststoffen und eine Vorrichtung (14) nach einem der vorstehenden Ansprüche.

Revendications

1. Dispositif (14) pour relier une installation de production (10) pour du gaz naturel non fossile à un réseau de distribution (12), en particulier un réseau public de distribution de gaz, comprenant :

une tuyauterie d'alimentation (18), pour introduire du gaz naturel non fossile, produit dans ladite installation de production (10), équipée d'au moins une soupape d'arrêt (24) ;

une tuyauterie de retour (30), pour retourner du gaz naturel non fossile, reliée fluidiquement à ladite tuyauterie d'alimentation (18), via une soupape d'arrêt (24) ;

une tuyauterie de décharge (28), pour décharger du gaz naturel non fossile, reliée fluidiquement à ladite tuyauterie d'alimentation (18), via une soupape d'arrêt (24) ;

des moyens de réduction de pression (38), pour réduire à une valeur prédéterminée la pression du gaz naturel non fossile produit dans ladite installation de production ;

un débitmètre (32), pour mesurer le débit du gaz naturel non fossile ;

un dispositif de mesure (22), pour mesurer le pouvoir calorifique du gaz naturel non fossile, en un emplacement situé en amont de la soupape d'arrêt (24) dans la tuyauterie d'alimentation (18) ;

un dispositif d'analyse (20), pour analyser au moins partiellement la composition du gaz naturel non fossile, en un emplacement situé en amont de la soupape d'arrêt (24) dans la tuyauterie d'alimentation (18) ;

un dispositif de commande (26), pour commander la soupape d'arrêt (24) sur à base des données fourniers par le dispositif de mesure (32) et le dispositif d'analyse (20).

2. Dispositif selon la revendication 1, dans lequel la soupape d'arrêt (24) dans la tuyauterie d'alimentation (18) comprend une soupape à trois voies.

3. Dispositif selon la revendication 1 ou 2, dans lequel le dispositif de mesure (22) est un dispositif de mesure de l'indice de Wobbe.

4. Dispositif selon l'une des revendications précédentes, dans lequel le dispositif d'analyse (20) est conçu pour déterminer au moins les teneurs en CO₂, O₂ et H₂S.

5. Dispositif selon l'une des revendications précédentes, dans lequel le dispositif d'analyse (20) est également connecté à la tuyauterie de retour (30).

6. Dispositif selon l'une des revendications précédentes, dans lequel la tuyauterie d'alimentation (18) est munie de dispositifs d'échantillonnage de gaz (36), pour prélever un échantillon à partir de la tuyauterie respective.

7. Dispositif selon l'une des revendications précédentes, dans lequel le dispositif de commande est muni d'une mémoire (34), pour stocker des données provenant du dispositif de mesure et du dispositif d'analyse.

8. Dispositif selon la revendication 7, dans lequel la mémoire (34) peut être lue à distance.

9. Dispositif selon la revendication 7 ou 8, dans lequel le dispositif est équipé d'installations télémétriques.

10. Ensemble comprenant une installation de production (10), pour produire du gaz naturel non fossile à partir d'un matériau résiduel biologique et un dispositif (14) selon l'une des revendications précédentes.

Drawing