E.i. Dupont De Nemours and Company

Research Triangle Institute

John Scott Newman

Clarence Garlan Law, Jr

James Arthur Trainham

Douglas John Eames

Kenneth B Keating

Dennie Turin Mah

James Arthur Trainham, Iii

William H Zimmerman

Vinci Martinez Felix

Francisco Jose Freire

David L Reichert

Walter John Simmons

Paul G Hoertz

Robert Joseph Kolouch

Thomas Frank Saturno

Bruce Arthur Kaiser

Charles C Seastrom

Edward Joseph Fahy

John Stanley Artysiewicz

Andrew Kelsey Birchenall

Christopher A Bonino

Robert Lloyd Freed

A heat transfer system and related method of heat transfer is provided. The heat transfer system includes a tubular receiver positioned to receive heat from a heat source, the receiver comprising one or more enclosed tubes configured for gravity-driven flow of a particulate heat transfer fluid therethrough in a dense, unfluidized state having a particle volume fraction of at least about 25%; and at least one storage vessel in fluid communication with the tubular receiver and positioned to receive the heat transfer fluid therefrom, wherein the particulate heat transfer fluid includes a plurality of particles of a metal-containing material having a melting point of greater than 800 C, the heat transfer fluid being substantially free of a liquid component.

Particulate heat transfer fluid and related system and method

The present invention relates to an electrochemical cell and a process for converting anhydrous hydrogen halide to halogen gas using a membrane-electrode assembly (MEA) or a separate membrane and electrode arrangement, such as gas diffusion electrodes with a membrane.

Electrochemical conversion of anhydrous hydrogen halide to halogen gas using a membrane-electrode assembly or gas diffusion electrodes

Electrochemical conversion of anhydrous hydrogen halide to halogen gas using an electrochemical cell

The invention relates to a process for electrochemically converting anhydrous hydrogen halide, such as hydrogen chloride, hydrogen fluoride, hydrogen bromide and hydrogen iodide, to essentially dry halogen gas, such as chlorine, fluorine, bromine and iodine gas, respectively. In a preferred embodiment, the present invention relates to a process for electrochemically converting anhydrous hydrogen chloride to essentially dry chlorine gas. This process allows the production of high-purity chlorine gas. In this process, molecules of essentially anhydrous hydrogen chloride are transported through an inlet of an electrochemical cell. The molecules of the essentially anhydrous hydrogen chloride are oxidized at the anode of the cell to produce essentially dry chlorine gas and protons, which are transported through the membrane of the cell. The transported protons are reduced at the cathode to form either hydrogen gas or water.

Electrochemical conversion of anhydrous hydrogen halide to halogen gas using a cation-transporting membrane

The invention relates to an electrochemical cell which has an electrode, a membrane disposed in contact with one side of the electrode and a current bus disposed on the other side of the electrode. A current distributor which is disposed between the electrode and the current bus distributes current to the electrode by electronic conduction. The current distributor is made of a non-porous layer of a conductive polymer composite material. The current distributor thus provides a barrier between the current bus and the reactant and the product of the cell. This is especially important in aggressive environments, such as hydrogen chloride. Thus, the cell of the present invention is particularly useful in converting anhydrous hydrogen halide directly to essentially dry halogen gas, such as anhydrous hydrogen chloride to chlorine gas, or in converting aqueous hydrogen chloride to wet chlorine gas.

Electrochemical cell having a current distributor comprising a

A process and a system produces isocyanate and converts anhydrous hydrogen chloride, which is a by-product of isocyanate production, to chlorine gas in an electrochemical cell. The chlorine is recycled to the isocyanate process. Any unreacted anhydrous hydrogen chloride may be recycled to the electrochemical cell. By recycling the anhydrous hydrogen chloride and the chlorine, the process and system are able to reduce the cost of producing isocyanate. In addition, this process and system process eliminate or at least substantially minimize the problems associated with disposal of anhydrous hydrogen chloride by turning it into a useful starting material in the isocyanate process.

Production of isocyanate using chlorine recycle

The present invention relates to an electrochemical cell, system and process for converting essentially anhydrous hydrogen halide to essentially dry halogen gas. The process of the present invention is useful for converting anhydrous hydrogen halide, in particular, hydrogen chloride, hydrogen fluoride, hydrogen bromide and hydrogen iodide, to a halogen gas, such as chlorine, fluorine, bromine, or iodine. In particular, in the present invention, water is provided to the cation-transporting membrane at the cathode in various ways. The present invention allows for recovery of a released fluid at the cathode-side of the membrane and recycling of the released fluid back to the cathode side of the membrane. In this way, the recovered, released fluid may be recycled to continuously supply water to the membrane, thereby allowing the limiting current density of the cell to be increased and/or controlled.

Membrane hydration in electrochemical conversion of anhydrous hydrogen

The invention relates to an electrochemical cell which has an electrode, a membrane disposed in contact with one side of the electrode, and a resilient flow field disposed on the other side of the electrode. The resilient flow field provides uniform electrical contact with the electrode. Such a flow field is preferably an elastomer, which can be be made by molding techniques, thereby decreasing the cost and increasing the ease with which such a flow field may be manufactured. The resilient flow field of the present invention is particularly useful in converting anhydrous hydrogen halide directly to essentially dry halogen gas, such as anhydrous hydrogen chloride to chlorine gas, although it may be used in a cell which converts aqueous reactants.

Electrochemical cell having a resilient flow field

The invention relates to an electrochemical cell which has an electrode, which may be either an anode or a cathode, and a membrane disposed in contact with one side of the electrode. An anode current bus is disposed on the other side of the anode, and a cathode current bus is disposed on the other side of the cathode. An anode current distributor collects current from the anode current bus and distributes it to the anode by electronic conduction, and a cathode current distributor collects current from the cathode and distributes it to the cathode bus by electronic conduction. The anode or the cathode current distributor is made of a metal which is treated by either nitriding, boriding or carbiding the metal in order to make the metal oxide growth resistant. In particular, the current distributor comprises tantalum that has been nitrided to form Ta.sub.2 N. The current distributor thus provides a barrier between the current bus and the electrode, and the anolyte, catholyte and products of the cell. This is especially important in aggressive environments, such as hydrogen chloride. Thus, the cell of the present invention is particularly useful in converting anhydrous hydrogen halide directly to essentially dry halogen gas, such as anhydrous hydrogen chloride to chlorine gas, or for converting aqueous hydrogen chloride to wet chlorine gas.

Electrochemical cell having an oxide growth resistant current distributor

The invention relates to an electrochemical cell having an electrode with a catalyst layer and a gas diffusion layer. The cell also includes a mass flow field for directing fluid to and away from the electrode. An additional gas diffusion layer is disposed between the gas diffusion layer and the flow field. This increases the diffusion resistance of the fluid. The electrochemical cell of the present invention is particularly useful in a process for electrochemically converting anhydrous hydrogen halide to essentially dry halogen gas, where it is necessary to control and increase limiting current. It is also possible to use the additional gas diffusion layer in an aqueous process electrochemical cell.

Electrochemical cell having a self-regulating gas diffusion layer

The present invention relates to an electrochemical cell and a process for producing a hydroxide solution, sulfuric acid and a halogen gas from a hydrogen halide and a sulfate solution. In particular, the sulfate solution may be an alkali metal sulfate solution, such as sodium or potassium sulfate solution, an alkaline earth metal sulfate solution or an ammonium sulfate solution. The cell and the process may use either an anhydrous or an aqueous hydrogen halide, namely, hydrogen chloride, hydrogen fluoride, hydrogen bromide and hydrogen iodide, to a respective dry halogen gas, such as chlorine, fluorine, bromine, or iodine, to produce hydrogen ions in order to split the alkali metal solution and form the sulfuric acid. The cell has two membrane-electrode assemblies, where an anode is disposed in contact with one membrane, and a cathode is disposed in contact with another membrane. The sulfate solution is fed in between the membrane-electrode assemblies.

Electrochemical cell and process for splitting a sulfate solution and

The invention relates to an electrochemical cell which has an electrode, a membrane disposed in contact with one side of the electrode and a mass flow field disposed on the other side of the electrode for directing fluid to and away from the electrode. The mass flow field comprises glassy carbon. The cell of the present invention is particularly useful in converting anhydrous hydrogen halide, in particular, hydrogen fluoride, directly to essentially dry halogen gas, such as anhydrous hydrogen fluoride to fluorine gas.

Electrochemical cell having a mass flow field made of glassy carbon

A conductive inflatable member is provided in an electrochemical cell between an electrode and a current for providing uniform contact pressure, and thus uniform electrical contact between the electrode and the current bus. The inflatable member may comprise a pair of flexible plates, where one plate is thinner than the other plate. The cell of the present invention is particularly useful in converting anhydrous hydrogen halide directly to essentially dry halogen gas, such as anhydrous hydrogen chloride to dry chlorine gas, or in converting aqueous hydrogen halide, such as aqueous hydrogen chloride, to wet chlorine gas.

Electrochemical cell having an inflatable member

Electrochemical conversion of anhydrous hydrogen halide to halogens gas

A particular anode comprising an electrochemically active material selected from the group consisting of the oxides of the elements tin, germanium and lead and mixtures comprising at least one of the respective oxides of such elements is useful in an electrochemical cell for the direct production of essentially dry halogen gas from essentially anhydrous halogen halide, or in a process for such production of essentially dry halogen gas. This cell or process may be used to produce halogen gas such as chlorine, bromine, fluorine and iodine from a respective anhydrous hydrogen halide, such as hydrogen chloride, hydrogen bromide, hydrogen fluoride and hydrogen iodide.

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Kensington, CA, United States of America

John Scott Newman