NOVELTY - A by-product from a chemical hydride solution is removed by withdrawing the chemical hydride solution from the reactor, cooling the solution, removing the precipitate, heating the solution and delivering the chemical hydride solution back to the reactor.    USE - Removing a by-product from a chemical hydride solution, especially for hydrogen generation in a fuel cell.    ADVANTAGE - The process reduces build-up of by-product in the chemical hydride solution. It is capable of responding in real time to the fuel (hydrogen) needs of a fuel cell. It maintains the by-product concentration below the by-product solubility limit.    DETAILED DESCRIPTION - Removal of a by-product from a chemical hydride solution includes:    (i) withdrawing a portion of the chemical hydride solution at a first temperature from the reactor;    (ii) cooling the portion of the chemical hydride solution to a second temperature below the first temperature, where a precipitate is formed from a portion of the by-product;    (iii) removing a portion of the precipitate from the portion of the chemical hydride solution;    (iv) heating the portion of the chemical hydride solution to a third temperature above the second temperature, where a remaining portion of the precipitate is dissolved in the portion of the chemical hydride solution; and    (v) delivering the portion of the chemical hydride solution back to the reactor.    The by-product is produced in the reactor configured to contact the chemical hydride solution with a catalyst.    An INDEPENDENT CLAIM is also included for a system for removing a by-product from a chemical hydride solution, comprising a circuit. The circuit includes:    (a) a reactor (112) having a catalyst for catalyzing the reaction of the chemical hydride solution to generate hydrogen;    (b) a pump (132) for withdrawing the portion of the chemical hydride solution at the first temperature from the reactor and returning the portion of the chemical hydride solution to the reactor;    (c) a cooling element for cooling the portion of the chemical hydride solution to the second temperature below the first temperature;    (d) a separator (164) for removing the portion of the precipitate from the portion of the chemical hydride solution; and    (e) a heater for heating the portion of the chemical hydride solution to a third temperature above the second temperature.    The remaining portion of the precipitate is dissolved in the portion of the chemical hydride solution. The cooling element is located in the circuit downstream of the reactor. The separator is located in the circuit downstream of the cooling element. The heater is located in the circuit downstream from the separator.    DESCRIPTION OF DRAWING(S) - The figure is a schematic flow diagram of a fuel cell system comprising a chemical hydride hydrogen generation system and a by-product removal system.    Reactor (112)    Pump (132)    Radiator (142)    Cooling fan (144)    Control unit (146)    Heat exchanger (154)    Separator (164)