A control system for mixing at least two materials in a physical system, for example cement and water for a well bore, having two or more tanks comprises at least two actuators, each actuator being operable to introduce a material into a first tank to form a first mixture, the first mixture flowing into a second tank to form a second mixture and a controller operable, based on a commanded input, to control the at least two actuators to obtain a density of either the first mixture or the second mixture and a volume flow rate of the second mixture out of the second tank, wherein the density is controlled independently from the volume flow rate, and wherein the commanded input comprises a commanded combined volume flow rate and a commanded combined mass flow rate of the materials passing through the actuators into the first tank.

Control system design for a mixing system with multiple inputs

A method comprises transporting a first stream of a carrier gas to a delivery device that contains a solid precursor compound. The first stream of carrier gas is at a temperature greater than or equal to 20° C. The method further comprises transporting a second stream of the carrier gas to a point downstream of the delivery device. The first stream and the second stream are combined to form a third stream, such that the dewpoint of the vapor of the solid precursor compound in the third stream is lower than the ambient temperature. The flow direction of the first stream, the flow direction of the second stream and the flow direction of the third stream are unidirectional and are not opposed to each other.

Vapor Delivery Device, Methods of Manufacture And Methods of Use Thereof

The present invention relates to an apparatus and process for polymerizing olefins. One embodiment comprises polymerizing at least one monomer in a first loop reactor in the presence of a catalyst to produce a first polyolefin fraction. A portion of the first polyolefin fraction is transferred to a second loop reactor, connected in series with the first loop reactor. The process further comprises polymerizing in the second loop reactor at least one monomer in the presence of a catalyst to produce a second polyolefin fraction in addition to the first polyolefin fraction. The combination of the first and second polyolefin fractions can produce a polymer resin fluff having bimodal molecular weight distribution.

Double Loop Technology

The present invention relates to an apparatus for preparing and supplying catalyst to an ethylene slurry loop polymerisation reactor and to an apparatus for controlling the injection of catalyst slurry in a polymerization reactor wherein polyethylene is prepared. The present invention a Iso relates to a method for optimising catalyst supply to a polymerisation reactor. The diluted catalyst is transferred to the reactor (1) using a membrane pump (5) controllable in function of the concentration of a reactant in said reactor (1).

Method and apparatus for preparing and supplying catalyst slurry to a polymerisation reactor.

A catalyst slurry for a polymerization reactor (42) can be prepared in a mixing tank (14) and the catalyst slurry fed to one or more storage tanks (18). The storage tanks can include agitators (54) so that the catalyst slurry is maintained at an essentially homogeneous solids-to-liquid ratio. From the storage tank(s), the catalyst slurry can be pumped (26) to the polymerization reactor (42) along a fluid passage (34) having a flow meter (38). The flow of the catalyst slurry can be continuous and/or adjusted based on a measured parameter. The catalyst slurry may be continuously and reliability fed to the polymerization reactor (42).

Catalyst slurry feeding assembly for a polymerization reactor

A continuous flow of particulate solids to a reactor is accomplished by first forming a heavy slurry in a storage tank, then transferring the heavy slurry to a mixing tank, where the heavy slurry is diluted to form a dilute slurry of desired density which can be continuously pumped to the reactor. Control of the particulate solids flow to the reactor is accomplished by calculating the flow rate of solid particles contained in the dilute slurry in an on-line computer, and comparing the calculated value to a desired value. The on-line calculation of particulate flow is based on the measured density and flow rate of the dilute slurry, and the predetermined densities of the dry particulate solids and the liquid diluent consituting the dilute slurry. The flow rate of the dilute slurry is continuously manipulated so as to maintain a desired flow rate of solid particles contained in the dilute slurry.

Pat Rooney

Papers

Particulate flow control