EP-4736992-A1 - SYSTEM AND METHOD FOR PERFORMING A REGENERATIVE DESULFURIZATION OF RAW BIOGAS

EP4736992A1EP 4736992 A1EP4736992 A1EP 4736992A1EP-4736992-A1

Abstract

System and method for performing a regenerative desulfurization of raw biogas. Raw biogas comprising hydrogen sulfide is injected in a container containing a material adapted for capturing and converting into solid sulfur the hydrogen sulfide. Biogas without hydrogen sulfide is extracted from the container, the hydrogen sulfide being captured and converted into the solid sulfur by the material. The injection of the raw biogas comprising the hydrogen sulfide in the container is then stopped. A regeneration gas heated at a predetermined temperature is injected in the container, the temperature allowing extraction of the sulfur from the material in the form of sulfur compound(s). The regeneration gas and the sulfur compound(s) are extracted from the container. The injection of the regeneration gas in the container is then stopped. A control device controls the execution of the regenerative desulfurization, using collected data representative of operating conditions of the system.

Inventors

LAVOIE, RENAUD
DOAN, Duy Tuan
VILLEMURE, Tristan

Assignees

Obeo Biogas

Dates

Publication Date: 20260506
Application Date: 20251029

Claims (15)

A system adapted for performing a regenerative desulfurization of raw biogas, the system comprising: a container (210) containing a material (220) adapted for capturing and converting into solid sulfur hydrogen sulfide; means for injecting the raw biogas comprising the hydrogen sulfide in the container (210); means for extracting biogas without hydrogen sulfide from the container (210), the hydrogen sulfide being captured and converted into the solid sulfur by the material (220); means for injecting a regeneration gas heated at a predetermined temperature in the container (210), the predetermined temperature allowing extraction of the sulfur from the material (220) in the form of one or more sulfur compounds; and means for extracting the regeneration gas and the one or more sulfur compounds from the container (210).
The system of claim 1, further comprising a control device (600) adapted for collecting (710) data representative of operating conditions of the system, executing (720) a control algorithm (612) using the collected data for determining at least one operating parameter of a component of the system, and applying (730) the at least one operating parameter to the component.
The system of claim 2, the operating parameter comprises at least one of the following: initiation or interruption of the injection of the raw biogas with hydrogen sulfide in the container (210), flow rate of the raw biogas with hydrogen sulfide injected in the container (210), initiation or interruption of the extraction of biogas without hydrogen sulfide from the container (210), flow rate of the biogas without hydrogen sulfide extracted from the container (210), initiation or interruption of the injection of heated regeneration gas in the container (210), flow rate of the heated regeneration gas injected in the container (210), initiating or stopping the extraction of the regeneration gas and the one or more sulfur compounds from the container (210).
The system of claim 2, wherein the data representative of operating conditions comprise at least one of the following: flow rate of raw biogas with hydrogen sulfide injected in the container (210), concentration in at least one of hydrogen sulfide, oxygen, ammonia, methane, carbon dioxide and humidity of the raw biogas injected in the container (210), flow rate of biogas extracted from the container (210), concentration in hydrogen sulfide of the biogas extracted from the container (210), estimation of a concentration of sulfur in the material (220), flow rate of regeneration gas injected in the container (210), concentration in nitrogen of the regeneration gas injected in the container (210), concentration in oxygen of the regeneration gas injected in the container (210), temperature of the regeneration gas injected in the container (210), flow rate of the one or more sulfur compound extracted from the container (210), concentration of the one or more sulfur compound extracted from the container (210), quantity of solid sulfur extracted from the container (210), concentration in oxygen of the regeneration gas extracted from the container (210), concentration in other exhaust gas extracted from the container (210), temperature inside the container (210), pressure inside the container (210), humidity inside the container (210), and weather conditions.
The system of claim 1 comprising a first container (210) consisting of the aforementioned container (210), the system further comprising: a second container (210') containing the material (220) adapted for capturing and converting into solid sulfur the hydrogen sulfide; means for injecting the raw biogas comprising the hydrogen sulfide in the second container (210'); means for extracting biogas without hydrogen sulfide from the second container (210'), the hydrogen sulfide being captured and converted into the solid sulfur by the material (220) in the second container (210'); means for injecting the regeneration gas heated at the predetermined temperature in the second container (210'), the predetermined temperature allowing extraction of the sulfur from the material (220) in the second container (210') in the form of one or more sulfur compounds; means for extracting the regeneration gas and the one or more sulfur compounds from the second container (210'); wherein the raw biogas with hydrogen sulfide is injected in the container (210) while the regeneration gas heated at the predetermined temperature is injected in the second container (210'), and the raw biogas with hydrogen sulfide is injected in the second container (210') while the regeneration gas heated at the predetermined temperature is injected in the first container (210).
The system of claim 1, wherein the material (220) is a porous carbonaceous solid material impregnated with metallic nanoparticles and the regeneration gas comprises nitrogen mixed with at least one of oxygen and carbon dioxide.
A method for performing a regenerative desulfurization procedure of raw biogas, the method comprising: (i) injecting (505) the raw biogas comprising hydrogen sulfide in a container (210), the container (210) containing a material (220) adapted for capturing and converting into solid sulfur the hydrogen sulfide; (ii) extracting (510) biogas without hydrogen sulfide from the container (210), the hydrogen sulfide being captured and converted into the solid sulfur by the material (220); (iii) stopping (515) the injection of the raw biogas comprising the hydrogen sulfide in the container (210); (iv) injecting (520) a regeneration gas heated at a predetermined temperature in the container (210), the predetermined temperature allowing extraction of the sulfur from the material (220) in the form of one or more sulfur compounds; (v) extracting (525) the regeneration gas and the one or more sulfur compounds from the container (210); and (vi) stopping (530) the injection of the regeneration gas in the container (210).
The method of claim 7, wherein steps (i) to (vi) are repeated several times.
The method of claim 7, further comprising collecting (710) by a control device (600) data representative of operating conditions of the regenerative desulfurization procedure, executing (720) by the control device (600) a control algorithm (612) using the collected data for determining at least one operating parameter of the regenerative desulfurization procedure, and applying (730) the at least one operating parameter to a component implementing the regenerative desulfurization procedure.
The method of claim 9, wherein the operating parameter comprises at least one of the following: initiation or interruption of the injection of the raw biogas with hydrogen sulfide in the container (210), flow rate of the raw biogas with hydrogen sulfide injected in the container (210), initiation or interruption of the extraction of biogas without hydrogen sulfide from the container (210), flow rate of the biogas without hydrogen sulfide extracted from the container (210), initiation or interruption of the injection of heated regeneration gas in the container (210), flow rate of the heated regeneration gas injected in the container (210), initiating or stopping the extraction of the regeneration gas and the one or more sulfur compounds from the container (210).
The method of claim 9, wherein the data representative of operating conditions comprise at least one of the following: flow rate of raw biogas with hydrogen sulfide injected in the container (210), concentration in at least one of hydrogen sulfide, oxygen, ammonia, methane, carbon dioxide and humidity of the raw biogas injected in the container (210), flow rate of biogas extracted from the container (210), concentration in hydrogen sulfide of the biogas extracted from the container (210), estimation of a concentration of sulfur in the material (220), flow rate of regeneration gas injected in the container (210), concentration in nitrogen of the regeneration gas injected in the container (210), concentration in oxygen of the regeneration gas injected in the container (210), temperature of the regeneration gas injected in the container (210), flow rate of the one or more sulfur compound extracted from the container (210), concentration of the one or more sulfur compound extracted from the container (210), quantity of solid sulfur extracted from the container (210), concentration in oxygen of the regeneration gas extracted from the container (210), concentration in other exhaust gas extracted from the container (210), temperature inside the container (210), pressure inside the container (210), humidity inside the container (210), and weather conditions.
The method of claim 7, further comprising collecting (710) by a control device (600) data representative of operating conditions of the regenerative desulfurization procedure, determining (720) by the control device (600) during the execution of steps (i) and (ii) based on the collected data that the material (220) is saturated with sulfur, and enforcing (730) by the control device (600) the interruption of steps (i) and (ii) and the initiation of steps (iii), (iv) and (v).
The method of claim 7, further comprising collecting (710) by a control device (600) data representative of operating conditions of the regenerative desulfurization procedure, determining (720) by the control device (600) during the execution of steps (iv) and (v) based on the collected data that regeneration of the material (220) is completed, and enforcing (730) by the control device (600) the interruption of steps (iv) and (v) and the initiation of steps (vi), (i) and (ii).
The method of claim 7, further comprising collecting (710) by a control device (600) data representative of operating conditions of the regenerative desulfurization procedure, and determining (720) by the control device (600) based on the collected data that material (220) needs to be added to the container (210) to replace material (220) consumed by the regenerative desulfurization procedure.
The method of claim 7, further comprising: simultaneously to steps (i) and (ii), injecting (520) the regeneration gas heated at the predetermined temperature in a second container (210'), the second container (210') containing the material (220) with deposited sulfur; and extracting (525) from the second container (210') the regeneration gas and one or more sulfur compounds generated by the extraction of the sulfur from the material (220) of the second container (210') under the action of the heated regeneration gas; and simultaneously to steps (iv) and (v), injecting (505) the raw biogas comprising the hydrogen sulfide in the second container (210'), the second container (210') containing the material (220) adapted for capturing and converting into solid sulfur the hydrogen sulfide; and extracting (510) biogas without hydrogen sulfide from the second container (210'), the hydrogen sulfide being captured and converted into the solid sulfur by the material (220) of the second container (210').

Description

TECHNICAL FIELD The present disclosure relates to the field of biogas-based energy generation. More specifically, the present disclosure relates to a system and method for performing a regenerative desulfurization of raw biogas. BACKGROUND Raw biogas can be produced by the decomposition of various organic matters, one of them being cattle manure (e.g. cow manure). Equipment adapted for raw biogas production (usually an anaerobic digester) can be deployed at a farm where organic matter suitable for raw biogas production is a by-product of the farm activities. The digester is used to process the organic matter (e.g. cattle manure) to obtain the raw biogas. The quality of raw biogas is not comparable to natural gas. The raw biogas (also referred to as digester gas) contains methane, but also carbon dioxide gas, hydrogen sulfide, ammoniac, hydrogen, oxygen, water vapor, etc. In particular, the concentration of methane in raw biogas is lower than in natural gas. Furthermore, different types of impurities are present in raw biogas, which are not present in natural gas (or at least at lower levels). Consequently, an upgrading process is generally implemented to upgrade raw biogas into biomethane having a quality similar to (or at least approaching) pipeline quality renewable natural gas (RNG). Upgrading equipment can also be deployed directly at the farm to perform the upgrading process. The present disclosure focuses on the capture and conversion of hydrogen sulfide (H2S) present in raw biogas into a sulfur element. Several processes for performing this operation are already known in the art. For example, iron(III) chloride (also referred to as ferric chloride) in liquid form is added directly to the digester. In another example, raw biogas exiting the digester is treated with activated carbon for the capture and conversion of hydrogen sulfide. The adsorption capacity is approximately 25%, meaning that one kilogram of activated carbon is capable of adsorbing 250 grams of sulfur under a solid form. In still another example, raw biogas exiting the digester is treated with iron(III) oxide-hydroxide FeO(OH) (also referred to as ferric oxyhydroxide) for the capture of the hydrogen sulfide. The adsorption capacity is approximately 50% to 60%, meaning that one kilogram of ferric oxyhydroxide is capable of capturing 500 to 600 grams of of hydrogen sulfide and converting it into a sulfur element under a solid form, which can be disposed of in an environmentally friendly way. However, the aforementioned processes have several drawbacks, including the need to dispose of the exhausted material used for capturing hydrogen sulfide from the raw biogas, once the material becomes saturated with sulfur. There is therefore a need for a new system and method for performing a regenerative desulfurization of raw biogas. SUMMARY According to a first aspect, the present disclosure relates to a system adapted for performing a regenerative desulfurization of raw biogas. The system comprises a container containing a material adapted for capturing and converting into solid sulfur hydrogen sulfide. The system comprises means for injecting the raw biogas comprising the hydrogen sulfide in the container. The system comprises means for extracting biogas without hydrogen sulfide from the container, the hydrogen sulfide being captured and converted into the solid sulfur by the material. The system comprises means for injecting a regeneration gas heated at a predetermined temperature in the container, the predetermined temperature allowing extraction of the sulfur from the material in the form of one or more sulfur compounds. The system comprises means for extracting the regeneration gas and the one or more sulfur compounds from the container. In a particular aspect, the system further comprises a control device adapted for collecting data representative of operating conditions of the system, executing a control algorithm using the collected data for determining at least one operating parameter of a component of the system, and applying the at least one operating parameter to the component. In a particular embodiment, the operating parameter comprises at least one of the following: initiation or interruption of the injection of the raw biogas with hydrogen sulfide in the container, flow rate of the raw biogas with hydrogen sulfide injected in the container, initiation or interruption of the extraction of biogas without hydrogen sulfide from the container, flow rate of the biogas without hydrogen sulfide extracted from the container, initiation or interruption of the injection of heated regeneration gas in the container, flow rate of the heated regeneration gas injected in the container, initiating or stopping the extraction of the regeneration gas and the one or more sulfur compounds from the container. In another particular embodiment, the data representative of operating conditions comprise at least one of the following: flow rate of raw biogas