Pressure or flow regulation method for gaseous hydrogen distribution systems

Abstract

The invention relates to a method for improving the stability of a hydrogen dispensing system. An example of such a system is a hydrogen powered vehicle fueling station. The vehicle is filled by a plurality of high pressure gaseous hydrogen tubes, usually one at a time. For safety and reliability reasons, a control requirement of such a system is to be able to deliver hydrogen to the fuel tank at a constant rate, maintaining a constant rate of pressure rise throughout the filling process. A dual pressure regulator device is proposed in order to better maintain continuity of flow and / or pressure during tube switching.

Description

background Technical Field

[0002] This disclosure relates to the management of pressurized gas flows used for refueling hydrogen fuel cell electric vehicles (FCEVs), particularly the pressure stability of hydrogen. Background Technology

[0004] High-pressure gaseous hydrogen stored in multiple tubes (tube bundles) is distributed to the vehicle's fuel tank (receiving tank) via pressure differences between the tubes and the fuel tank. To maximize the utilization of the tube bundle's storage capacity, the strategy is to minimize the average pressure difference between the tubes and the fuel tank during refueling. The fuel tank is refueled in a cascaded manner, starting with the tube with the lowest pressure difference and proceeding one tube at a time. When the pressure in the tube reaches a preset limit relative to the fuel tank pressure, the system switches to the tube with the second lowest pressure difference between the tube and the receiving tank. This switching is accomplished by first opening the isolation valve on the inlet tube and then closing the isolation valve on the outlet tube. This sequence is repeated until the fuel tank reaches the desired pressure.

[0005] The commonly accepted method for regulating flow rate, and thus the rate of pressure rise, is through a pressure control valve (PCV). However, this single PCV setting cannot guarantee a stable flow rate to the receiving tank. If the valve remains in automatic mode, a flow surge is likely to occur in the receiving tank during pipe switching due to a pressure spike (peak) upstream of the PCV. On the other hand, if the PCV switches to inactive mode (i.e., the closed position), the flow to the receiving tank will be interrupted. Summary of the Invention

[0006] The present invention will be understood by referring to the following embodiments:

[0007] A system is disclosed for adding pressurized gas to a receiving container fluidly connected thereto. The system includes: a) multiple groups of pressurized gas containers, each group having multiple pressurized gas containers, wherein each pressurized container in a group is fluidly connected to a common group manifold and a common group pressure control valve (PCV). b) A common group PCV configured downstream of the group and all its pressurized gas containers, the common group PCV being adapted to control the flow of pressurized gas from the group to the receiving container. c) These group PCVs are configured and adapted to operate sequentially in response to computer control. d) The computer control is configured and specifically programmed to control the opening and closing of these group PCVs in response to a pressure value representing the pressurized gas pressure in a first pressurized container of a first group (group A). The computer control program is specifically programmed to execute the following steps: A) Detect the first pressure in the first pressurized gas container of the first group (Group A); B) Compare the first pressure in the first pressurized gas container of the first group (Group A) with the pressure of the receiving container; C) When the comparison result of (B) reaches a predetermined minimum pressure difference, compare the pressure value of each pressurized gas container in the second group (Group B) to determine the second pressurized gas container with the smallest pressure difference with the receiving pressure container; D) Open the second isolation valve of the second pressurized gas container of the second group to establish fluid communication between the second pressurized gas container and the second group PCV; E) Based on the pressure decay of the pressurized gas flow through the first group PCV, proportionally open the second group PCV to maintain the minimum pressure of the gas flow to the receiving container; and F) When the first pressure of the first pressurized gas container drops to a second preset pressure difference with the pressure of the receiving container, close the first PCV.

[0008] A method for adding pressurized gas to a container fluidly connected to the aforementioned system is also disclosed. The method includes the following steps: a) detecting a first pressure in a first pressurized gas container of a first group (Group A). ​​b) comparing the first pressure in the first pressurized gas container of the first group (Group A) with the pressure of the receiving container. c) when the comparison result of (B) reaches a predetermined minimum pressure difference, comparing the pressure values ​​of each pressurized gas container in a second group (Group B) to determine the second pressurized gas container with the smallest pressure difference with the receiving pressure container. d) opening a second isolation valve of the second pressurized gas container in the second group to establish fluid communication between the second pressurized gas container and the second group PCV. e) proportionally opening the second group PCV based on the pressure decay of the pressurized gas flow through the first group PCV to maintain a minimum pressure for the gas flow to the receiving container. f) closing the first PCV when the first pressure in the first pressurized gas container drops to a second preset pressure difference with the pressure of the receiving container.

[0009] The above systems and / or methods may include one of the following aspects:

[0010] - Close the first isolation valve of the first pressurized gas container simultaneously with or after (F).

[0011] - The computer control is configured and specifically programmed to perform an additional setpoint exchange process, wherein the setpoint of the second PCV is set to a predetermined value lower than the setpoint of the first PCV, and then the predetermined setpoint value is reduced to zero.

[0012] - The computer control is configured and specifically programmed to repeat (A)-(F) on the second and third pressurized containers of the first group.

[0013] -g) Close the first isolation valve of the first pressurized gas container simultaneously with or after step f).

[0014] - During the setpoint exchange process, the setpoint of the second PCV is set to a predetermined value lower than the setpoint of the first PCV, and then the predetermined setpoint value is reduced to zero.

[0015] - Repeat steps a)-f) for the second and third pressurized containers in the first group. Attached Figure Description

[0016] Figure 1 This illustrates a prior art system for generating a pressurized gas flow;

[0017] Figure 2 An embodiment of the invention is shown, which has two separate groups of pressurized gas storage containers, each group having a pressure control valve connected to a common outlet conduit;

[0018] Figure 3 A diagram showing the pressure setpoint exchange process is provided. Detailed Implementation

[0019] The purpose of this invention is to eliminate the above-mentioned disadvantages by dividing a plurality of tubes (1-14) into two groups (group A and group B), each group having a common PCV (PCV-A and PCV-B), so that filling can be performed alternately between these groups.

[0020] The switching order is managed via a computer (not shown), as follows:

[0021] • Refueling begins from the pipe (pipe 1) in group A with the smallest pressure differential to the vehicle's fuel tank, and PCV-A controls the rate of pressure increase. When the pressure differential between pipe 1 in group A and the receiving tank decreases to a preset limit, the next refueling pipe (pipe 2) with the smallest pressure differential to the vehicle's fuel tank in group B is selected sequentially, and the corresponding isolation valve is opened to pressurize the pipeline and manifold head up to PCV-B. After the isolation valve is opened and its upstream is pressurized, PCV-B switches to active mode (automatic mode), whose settings follow the current setpoint of PCV-A. As the pressure differential between group A and the receiving tank continues to decrease to the point that PCV-A can no longer maintain full flow, PCV-B will begin to open to provide supplemental flow, and group B gradually comes online (…). Figure 3 When the pressure differential reaches the preset limit, group A will be taken offline by gradually closing PCV-A and then its isolation valve. This cycle is repeated between groups A and B until the receiving tank reaches the desired pressure.

[0022] This transition can be further improved by employing a setpoint swapping strategy. PCV-B switches to automatic mode when the offset is below the setpoint of PCV-A. This offset is then gradually reduced to zero.

[0023] Industrial applicability

[0024] This invention is at least industrially applicable to refueling hydrogen FCEVs.

[0025] While the invention has been described in conjunction with specific embodiments thereof, it will be apparent to those skilled in the art, in light of the foregoing description, that many alternatives, modifications, and variations will be apparent to those skilled in the art. Therefore, it is intended to encompass all such alternatives, modifications, and variations falling within the spirit and broad scope of the appended claims. The invention may suitably include, consist of, or be substantially composed of the disclosed elements, and may be practiced without any undisclosed elements. Furthermore, any language relating to sequence, such as "first" and "second," should be understood in an exemplary sense rather than a restrictive one. For example, those skilled in the art will recognize that certain steps may be combined into a single step.

[0026] The singular forms “a / an” and “the” include plural indicators unless the context clearly indicates otherwise.

[0027] The word “comprising” in the claims is an open-ended transitional term, meaning that the subsequently determined claim elements are a non-exclusive list (i.e., anything else may be additionally included and remain within the scope of “comprising”). Unless otherwise stated herein, “comprising” as used herein may be replaced by the more restrictive transitional terms “consistently consisting of” and “comprises of”.

[0028] In the claims, "provide" is defined as meaning to supply, provide, make available, or prepare something. This step can, conversely, be performed by any actor in the absence of explicit language in the claims.

[0029] Optional or alternative means that the events or circumstances described below may or may not occur. This specification includes instances in which events or circumstances occur and instances in which events or circumstances do not occur.

[0030] In this document, a range may be expressed as from about one specific value and / or to about another specific value. When such a range is expressed, it should be understood that another embodiment is from that one specific value and / or to that other specific value, together with all combinations within the range.

[0031] All references identified herein are hereby incorporated in their entirety by reference, and each reference is cited for the purpose of obtaining specific information.

Claims

1. A pressurized gas delivery system for adding pressurized gas to a receiving container fluidly connected thereto, the system comprising: a) Multiple pressurized gas container groups, each group having multiple pressurized gas containers, wherein each pressurized container in a group is fluidly connected to a common group manifold and a common group pressure control valve. b) A common group pressure control valve is located downstream of the group and all its pressurized gas containers, and the common group pressure control valve is adapted to control the pressurized gas flow from the group to the receiving container. c) These shared group pressure control valves are configured and adapted to operate sequentially in response to computer control. d) The computer control is configured and specifically programmed to control the opening and closing of these common group pressure control valves in response to a pressure value representing the pressurized gas pressure in the first pressurized container of the first group (Group A), and the computer control is specifically programmed to perform the following steps: (A) Detect the first pressure in the first pressurized gas container of the first group (Group A). (B) Compare the first pressure in the first pressurized gas container of the first group (Group A) with the pressure in the receiving container. (C) When the comparison result of step (B) reaches the predetermined minimum pressure difference, the pressure value of each pressurized gas container in the second group (group B) is compared to determine the second pressurized gas container with the smallest pressure difference with the receiving pressure container. (D) Open the second isolation valve of the second pressurized gas container in the second group to establish fluid communication between the second pressurized gas container and the second group of pressure control valves. (E) Based on the pressure decay of the pressurized gas flow through the first set of pressure control valves, the second set of pressure control valves is opened proportionally to maintain a minimum pressure for the gas flow to the receiving container, and (F) When the first pressure of the first pressurized gas container drops to a second preset pressure difference with the pressure of the receiving container, the first set of pressure control valves is closed.

2. The system of claim 1, further comprising steps (G) and (F) simultaneously or subsequently closing the first isolation valve of the first pressurized gas container.

3. The system as described in claim 1, wherein, The computer control is configured and specifically programmed to perform an additional setpoint exchange process, wherein the setpoint of the second set of pressure control valves is set to a predetermined value lower than the setpoint of the first set of pressure control valves, and then the predetermined setpoint value is reduced to zero.

4. The system as claimed in claim 1, wherein, The computer control is configured and specifically programmed to repeat steps (A)-(F) for the second and third pressurized containers of the first group.

5. A method for adding pressurized gas to a container fluidly connected to a pressurized gas delivery system as claimed in claim 1, the method comprising: a) Detect the first pressure in the first pressurized gas container of the first group (Group A). b) Compare the first pressure in the first pressurized gas container of the first group (Group A) with the pressure in the receiving container. c) When the comparison result of (B) reaches the predetermined minimum pressure difference, the pressure value of each pressurized gas container in the second group (group B) is compared to determine the second pressurized gas container with the smallest pressure difference with the receiving pressure container. d) Open the second isolation valve of the second pressurized gas container in the second group to establish fluid communication between the second pressurized gas container and the second group of pressure control valves. e) Based on the pressure decay of the pressurized gas flow through the first set of pressure control valves, the second set of pressure control valves is opened proportionally to maintain a minimum pressure for the gas flow to the receiving container, and f) When the first pressure of the first pressurized gas container drops to a second preset pressure difference with the pressure of the receiving container, the first set of pressure control valves is closed.

6. The method of claim 5, further comprising step g), simultaneously with or after step f), closing the first isolation valve of the first pressurized gas container.

7. The method of claim 5, further comprising a setpoint exchange process, wherein the setpoint of the second set of pressure control valves is set to a predetermined value lower than the setpoint of the first set of pressure control valves, and then the predetermined setpoint value is reduced to zero.

8. The method of claim 5, further comprising repeating steps a)-f) on the second and third pressurized containers in the first group.

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