Asea Brown Boveri Ag

Alstom

Peter Baumann

Francisco Leonardo Blangetti

Christian Stucki

Walter Novak

A power plant, from which large amounts of process steam are removed and to which large amounts of make-up water are supplied continuously, has a degassing system (,) for the make-up water supplied, which as part of the condensation system is connected to the condenser (,) of the power plant. Bleed pumps (,) are connected to the condenser (,) via a first suction line (,) and to the degassing system (,) via a second suction line (,) and remove a mixture of steam and non-condensable gases from the power plant. A control member (,), such as for example a regulating valve, a regulating diaphragm or a readjustable restrictor, is arranged in at least one of the two lines (,), with the result that the suction capacity in that line and the distribution of the suction capacity to the two lines (,) can be adjusted during operation of the power plant.

Degassing system for power plants

In a steam condenser which is set up in an on-floor arrangement and in which the steam is condensed on tubes through which cooling water flows and which are combined in separate banks, the tubes of a bank arranged in rows enclosing a hollow space, a cooler for the non-condensable gases is arranged in the hollow space. The sectional banks are horizontally directed in their longitudinal extent and are arranged vertically one above the other. The cooler for the non-condensable gases has its suction action directed toward a zone below the longitudinal center line of the individual bank. The hollow space is connected to a compensating lane in the interior of the bank, the longitudinal center line of which compensating lane, on account of the asymmetrical condensate loading in the horizontally oriented sectional bank and the asymmetrical localization of the pressure minimum in the tube assembly, runs below the longitudinal center line of the sectional banks.

Steam condenser

In a steam condenser in which the steam is condensed on tubes (13) through which cooling water flows and which are combined in separate banks (20), each bank (20) being subdivided into compartments (10) by supporting plates (5) arranged perpendicularly to the tubes (13), a residual-steam/inert-gas mixture is drawn out of a precooler (2) via orifices (9) into an air cooler (3). The residual steam is condensed in the air cooler (3) and the collecting condensate (23) flows off on account of a slope of the air-cooler bottom (21) through a recess (18) to an adjacent compartment (10) having an air-cooler bottom (21) situated at a lower level. In this case, the condensate (23) flowing off from a compartment (10) situated at a higher level is retained at a retaining wall (22) on the air-cooler bottom (21) of the compartment (10) having the air-cooler bottom situated at the lowest level, this retaining wall (22) being arranged parallel to a supporting plate (5). Due to the retained condensate (23), the recesses (18) in the supporting plates for the condensate flow from a compartment (10) situated at a higher level can be closed hydraulically in both a gas-tight and a steam-tight manner.

In the case of the method for determining the total mass flow of a gas mixture (2) which flows through a line (1) under pressure, a gas contained in the gas mixture is used as tracer (3). With the aid of pressure measurements (9, 10) of the gas mixture, total pressure and of the tracer partial pressure, the molar proportions of the tracer in the gas mixture are first ascertained. In this case the pressure measurements take place during a first phase, with the line system (1) gas-tight, and in a further phase with the system enriched with tracer. Solving the mass balances for the gas mixture and for the tracer makes it possible, by substituting the already determined tracer molar proportions, to calculate the total mass flow. Tracer enrichment of the gas mixture is carried out at supercritical pressure ratios between the vacuum prevailing in the line and the pressure of the tracer to be fed in by a critical orifice (4) which is built into the line (1) upstream of the pressure measurement locations (9, 10).

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Sulz, Switzerland

Peter Baumann