The invention relates to a device for continuously incorporating solids into a pressurised fluid which is either liquid or gaseous, comprising a string of pistons sliding inside a tube in order to define therein hermetically separated chambers, which tube is brought to increasing and then decreasing pressures by feeding and venting fluid. The solids are incorporated into the fluid at the inlet of the tube. In the centre of the tube, there are connections to a circuit in which the fluid flows and which feeds the solids towards a reactor where said solids are treated. This arrangement also makes it possible for divided solid materials to be extracted from the reactor, such that said solid materials are continuously depressurised.

Among other things, hydrogen is released from water at a first location using energy from a first energy source; the released hydrogen is stored in a metal hydride slurry; and the metal hydride slurry is transported to a second location remote from the first location.

A method of monitoring a solid component of a reactor feed stream in a polymer production system, comprising (a) measuring a turbidity of the reactor feed stream, wherein the reactor feed stream comprises a solid component of a polymerization catalyst system, and (b) translating the turbidity of the reactor feed stream into a concentration of the solid component in the reactor feed stream. A method of monitoring a solid component of a reactor feed stream in a polymer production system, comprising (a) measuring a turbidity of a precontactor feed stream, wherein the precontactor feed stream comprises a solid component of a polymerization catalyst system, and (b) translating the turbidity of the precontactor feed stream into a concentration of the solid component in a precontactor effluent stream, wherein the precontactor effluent stream comprises the reactor feed stream.

Slurry flow valves may be used to control flow in a gas-phase polymerization reactor. For example, a system may include at least three injection nozzles fluidly connected to a gas-phase polymerization reactor, wherein the at least three injection nozzles are configured to carry' a modified catalyst slurry; at least three lines connected to the at least three injection nozzles, wherein the at least-three lines comprise a first line connected to a first injection nozzle, a second line connected to a second injection nozzle, and a third line connected to a third injection nozzle; and at least three slurry? flow valves in contact with the at least three lines, wherein the at least three slurry flow valves comprise a first slurry flow valve, a second slurry flow valve, and a third slurry' flow valve. Preferably, the valves can each be independently controlled to regulate flow therethrough.