Abstract: Disclosed herein is a method for generating a composite cryptographic signature. The method comprises receiving a message and a first part of a first party signature, wherein the first part of the first party signature is derived from the message and a first share of a first private key. The method further comprises generating a first party signature from the first part of the first party signature and a second share of the first private key and generating a second party signature from the message and a second private key. The method further comprises combining the first party signature and the second party signature to generate a composite cryptographic signature. An apparatus, a computer-readable medium for implementing this method are also disclosed.

Abstract: A boiler comprises a boiler gas exhaust providing an exhaust for recuperated gases; and a secondary heat exchanger comprising: an economizer cold fluid inlet connected to a source of cold fluid; an economizer cold fluid outlet fluidly connected to the economizer cold fluid inlet and located thereabove, the cold fluid circulating upwardly from the economizer cold fluid inlet towards the economizer cold fluid outlet; a hot gas inlet for receiving the recuperated gases from the boiler gas exhaust; and a hot gas outlet fluidly connected to the hot gas inlet through the secondary heat exchanger, the recuperated gases circulating from the hot gas inlet toward the hot gas outlet; wherein the recuperated gases cross the secondary heat exchanger and exhaust by the hot gas outlet, the cold fluid being heated between the economizer cold fluid inlet and the economizer cold fluid outlet thereby resulting in a preheated fluid.

Abstract: An economizer arrangement particularly suitable for new or retrofit application to existing steam generators provides a water cooled stringer support tube system which can accommodate firing a wide range of fuels with varying characteristics in the steam generator. The economizer arrangement according to the present invention is particularly suited for retrofit applications to large supercritical steam generators. The use of water cooled stringer tube supports allows for higher flue gas temperatures in comparison to conventional non-cooled mechanical economizer supports. These features are provided in a design which fits within the existing economizer envelope of the steam generator.

Abstract: A feedring for use with an axial flow preheat steam generator which utilizes a double wrapper to direct feedwater flow to the cold leg tube bundle region. The feedring is positioned directly over the double wrapper and includes a plurality of standpipes spaced circumferentially along the feedring. The standpipes respectively extend vertically from a lower portion of an interior of the feedring upward through the interior of the feedring. The standpipes have a feedwater intake in the upper portion of the feedring to minimize the potential for vapor formation and bubble collapse water hammer. The components of the standpipe are arranged to minimize the transmission of entrained loose parts from traveling with the feedwater to the tube bundle. A feedwater discharge is provided at the exit of the standpipe at or below the bottom of the feedring, for evenly distributing the feedwater into the double wrapper downcomer.

Abstract: A modified portion of gas hot water heater exhaust vent tubing. Cold water tubing is wound around the outside of a tube of the same interior diameter and vertical orientation as the exhaust vent tube that typical gas hot water heaters are designed to operate with. Said vent tube is insulated, double-walled, or is otherwise of a sufficient thickness and/or appropriate material composition so as to prevent condensation occurring on its interior surfaces, and may contain small vents or perforations that allow hot exhaust gases to communicate with the cold water tubing. An insulating jacket is located proximally to the cold water tubing whereby the insulating jacket, cold water tubing and vent tube portion are enclosed within a housing portion. The present invention is meant to easily replace an existing section of exhaust venting typically used in a consistent vertical orientation with a common gas hot water heater.

Abstract: One exemplary embodiment of the present invention can be a fired heater for a hydrocarbon conversion process. The fired heater includes inlet and outlet headers or manifolds, a set of heater tubes with each heater tube having an inlet and an outlet, at least one restriction orifice adjacent the inlet of at least one heater tube. The restriction orifice may be within the inlet manifold and adjacent the inlet of a heater tube, or between the inlet manifold and the inlet to the heater tube. A process may include passing a hydrocarbon stream through the fired heater described herein during the course of operating a hydrocarbon conversion process.

Abstract: In a demineralization apparatus, a mixed bed of a gel type cation exchange resin having a moisture holding capacity of 41% or less or a degree of crosslinkage of 12% or greater is employed along with a porous type anion exchange resin. As a result, oxidation degradation of the cation exchange resin due to hydrogen peroxide can be inhibited and the performance of the ion exchange resins and of the condensate water demineralizer can be stabilized and maintained for a long period of time.

Abstract: A support plate for retaining tube array spacing within a heat exchanger tube and shell structure. The support plate having a plurality of individual tube receiving aperture formed therein. Each apertures has at least three inwardly protruding members and bights are formed therebetween when the tube associated therewith is lodged in place to establish secondary fluid flow through the support plate. The inwardly protruding members terminate in flat lands that restrain but do not all contact the outer surface of the respective tube. These flat lands minimize fretting wear and eliminate potential gouging of the outer wall of the tube. The plate wall forming each aperture has an hourglass configuration which, inter alia, reduces pressure drop, turbulence and local deposition of magnetite and other particulates on the support plates.

Abstract: A steam generation device comprising two cylinders, an inner and an outer cylinder, the inner cylinder forming a combustion chamber into which streams of air, water and fuel are released under computer control. Water is introduced under pressure into the plenum formed by the inner and outer cylinder and exits into the combustion chamber top holes drilled at an angle into the inner cylinder. Using a model of the combustion process and the flame's gas envelope pressure, the computer maintains combustion and steam production without extinguishing the flame, in response to demands for differing quantities of steam volume, temperature and pressure.

Abstract: A model steam generator for simulating the environment inside a nuclear steam generator in order to monitor the condition of the heat exchange tubes of the nuclear steam generator is disclosed herein. The model steam generator includes an electrically-powered thermosyphon heating means for circulating a flow of vapor and condensate through the sample tube in a closed loop. The thermosyphon includes riser tubes which are concentrically disposed within the sample heat exchange tube along a substantial portion of the longitudinal axis thereof for both directing a stream of steam into the inside walls of the heat exchange tubes, and for insulating this flow of steam from the resulting stream of condensate which flows down from the inner walls of the sample tubes. The elimination of the counter-current forces between the stream of steam and the downflowing film of condensate prevents the formation of heat-obstructing ripples of condensate on the inner walls of the sample heat exchange tubes.

Abstract: A furnace having a fire box at one end of a multi-unit cell boiler receives combustible refuse and delivers hot combustion gases through passages between water cells of the multi-unit cell boiler. The combustion gases enter an exhaust stack at the far end of the boiler after giving up most of their contained heat to the water circulating through the cells. Simultaneously, water flows through the base of the boiler on a circuitous path from its end adjacent to the exhaust stack toward the furnace and through cooling walls of the furnace and then through a holding tank to a pump which delivers the water to a header communicating with the cells of the boiler unit most distant from the furnace. The water being pumped into the cells is preheated to boost the thermal efficiency of the boiler. Steam generated in the boiler enters a steam header connected with the cell boiler unit nearest the furnace.

Abstract: An improved model steam generator for simulating the conditions within a nuclear steam generator in order to monitor the condition of the heat exchange tubes and tubesheet of the nuclear steam generator is disclosed herein. The improved model steam generator includes a highly effective separator assembly for separating water droplets entrained within the steam flowing out of the outlet of the secondary side of the generator formed from a plurality of separator grids, each of which includes an array of semi-cylindrical deflector members. The grids are vertically stacked with the deflector members transversely disposed to the flow of steam generated by the model steam generator. Each of the parallel arrays of deflector members in each grid is angularly disposed approximately 45.degree. to the deflector members in the grids above it and below in order to provide a tortuous path for the flow of steam ascending therethrough.

Abstract: A heater comprising two separate tube nests of which one (29) heats the circulating water by condensation and supercooling and the other (39) heats a partial flow of this water by the desuperheating of steam. Steam is admitted through pipe (16). The foregoing partial flow of water comes from the desuperheating zone of a heater located downstream and is admitted through a manifold (41). Pipes (39) are wound round a central drum (43).

Abstract: A bottom supported steam generator for burning solid fuel with a vertical tube bank connecting an upper steam drum with a lower water drum. Horizontal economizer tubes are interspersed between the vertical tubes of the steam generating bank.

Abstract: A condensate recovery system wherein a condensate receiver is provided between a boiler and a feed water tank with condensate being introduced into the condensate receiver during a period when water is not being fed to the boiler and with water being fed into the boiler during a subsequent feeding period by pumping make-up water into the condensate receiver. The system is arranged so that equalizing the pressure of the condensate inlet port of the condensate receiver with that at the low temperature water outlet port of the condensate receiver allows condensate to flow by gravity and replace low temperature water therein, leaving the condensate receiver filled with water.