Multi-stage rebalancing reactor for redox flow battery system
A method for a redox flow battery system may include flowing an electrolyte from an electrolyte storage tank to a multi-stage rebalancing reactor, the multi-stage rebalancing reactor comprising reactor vessels grouped to form stages. Hydrogen gas may be injected into the electrolyte upstream of the multi-stage rebalancing reactor via a gas line and a metal ion of the electrolyte may be chemically reduced by oxidizing the hydrogen gas at a catalyst bed of each of the reactor vessels to maintain a charge balance of the electrolyte and a pH of the electrolyte within a predetermined range.
1. A method for a redox flow battery system, comprising:
flowing an electrolyte from an electrolyte storage tank to a multi-stage rebalancing reactor, the multi-stage rebalancing reactor comprising reactor vessels grouped to form stages, wherein the reactor vessels in a first stage of the stages are fluidly coupled to reactor vessels in a second stage of the stages, the second stage downstream of the first stage;
injecting hydrogen gas into the electrolyte upstream of the multi-stage rebalancing reactor via a gas line configured to siphon hydrogen gas from a head space of the electrolyte storage tank, wherein injecting hydrogen gas into the electrolyte includes injecting the hydrogen gas at each of the first stage and the second stage via a first injector and a second injector arranged upstream of each of the first stage and the second stage; and
chemically reducing a metal ion of the electrolyte by oxidizing the hydrogen gas at a catalyst bed of each of the reactor vessels to maintain a charge balance of the electrolyte and a pH of the electrolyte within a predetermined range.
2. The method of claim 1 , wherein flowing the electrolyte from the electrolyte storage tank includes operating a pump arranged downstream of the electrolyte storage tank and upstream of the multi-stage rebalancing reactor to drive flow of the electrolyte.
3. The method of claim 2 , further comprising flowing hydrogen with the electrolyte to the multi-stage rebalancing reactor to form a mixture of hydrogen gas and electrolyte downstream of the pump, and wherein the mixture of hydrogen gas and electrolyte is distributed between the first stage and the second stage.
4. The method of claim 1 , further comprising, responsive to a detected increase in electrolyte pH beyond a threshold amount, increasing an amount of hydrogen gas delivered to the multi-stage rebalancing reactor by one or more of increasing a speed of a pump and increasing a number of injectors injecting hydrogen into the electrolyte.
5. The method of claim 1 , further comprising, responsive to a detected imbalance in electrolyte state of charge, increasing an amount of hydrogen gas delivered to the multi-stage rebalancing reactor by one or more of increasing a speed of a pump and increasing a number of injectors injecting hydrogen into the electrolyte.
6. The method of claim 1 , wherein the metal ion of the electrolyte is reduced during charging of the redox flow battery system.
7. A method for rebalancing an electrolyte, comprising:
distributing a mixture of hydrogen gas and the electrolyte between multiple reactor vessels of a stage of a multi-stage rebalancing reactor, wherein the multi-stage reactor includes stages arranged in series, each of the stages comprising multiple reactor vessels arranged in parallel to reduce ferric ions in the electrolyte and oxidize the hydrogen gas, wherein each of the multiple reactor vessels includes an inlet at a bottom end of a respective reactor vessel, an outlet at an upper end of the respective reactor vessel, and a catalyst bed enclosed within an outer housing of the respective reactor vessel.
8. The method of claim 7 , wherein the electrolyte is distributed amongst the multiple reactor vessels by flowing the electrolyte through a manifold arranged upstream of the stage.
9. The method of claim 7 , wherein the hydrogen gas is obtained from a head space of an electrolyte storage tank.
10. The method of claim 7 , wherein the mixture of the hydrogen gas and the electrolyte is formed by injecting the hydrogen gas into the electrolyte upstream of the multi-stage rebalancing reactor.
11. The method of claim 10 , wherein the hydrogen gas is injected into the electrolyte via at least one injector positioned upstream of the stage.
12. The method of claim 10 , wherein the hydrogen gas is injected upstream and downstream of the multiple reactor vessels using a branched gas line.
13. The method of claim 7 , wherein the catalyst bed is configured as a jelly-roll comprising at least one catalyst layer, a substrate layer, and a spacing layer.
14. A method for a redox flow battery system, comprising:
flowing an electrolyte from an electrolyte storage tank to a multi-stage rebalancing reactor, the multi-stage rebalancing reactor comprising reactor vessels grouped to form stages, wherein the reactor vessels in a first stage of the stages are fluidly coupled to reactor vessels in a second stage of the stages, the second stage downstream of the first stage;
injecting hydrogen gas into the electrolyte upstream of the multi-stage rebalancing reactor via a gas line configured to siphon hydrogen gas from a head space of the electrolyte storage tank;
chemically reducing a metal ion of the electrolyte by oxidizing the hydrogen gas at a catalyst bed of each of the reactor vessels to maintain a charge balance of the electrolyte and a pH of the electrolyte within a predetermined range; and
responsive to a detected increase in electrolyte pH beyond a threshold amount, increasing an amount of hydrogen gas delivered to the multi-stage rebalancing reactor by one or more of increasing a speed of a pump and increasing a number of injectors injecting hydrogen into the electrolyte.