Method and means for generating electricity and vaporizing a liquid in a thermal power station

Claim 3

A method according to claim 1, characterized in that, at low electric power, at least half the quantity of the preheated liquid is led to the vaporizing process, that the remainder of the preheated liquid is heated by means of said excess capacity, and that some of the liquid heated in this way is led to the top of the liquid-container and the remainder of the liquid heated in this way is led to the vaporizing process.

Claim 4

A method according to claim 2, characterized in that the remainder of the preheated liquid is led off before the final stage of the preheating process, or some stage before the final stage.

Claim 5

A method according to claim 1, characterized in condensing the steam produced in at least some of, and preferably all of the vaporizing stages by bringing the steam into direct contact with cooler condensate from the vaporizing stage immediately subsequent passing the condensate from the first vaporizing stage in heat-exchanging counter-flow to the liquid entering flowing through the preheating stages, and returning part of the condensate leaving the first preheating stage to the last vaporizing stage to condense the steam generated in said last vaporizing stage.

Claim 6

A plant for use as a thermal power station operating with variable electric power production in which the excess heat generated at low electric power production is used for vaporizing a liquid in a multi-stage vaporizing arrangement, the plant comprising a heat-generating machine, a turbine driven by this heat-generating machine, an electric generator driven by the turbine, an evaporation apparatus comprising a plurality of stages for vaporizing a liquid and at least one stage for preheating the liquid, a heat-exchanger for additional heating of the pre-heated liquid by means of the excess capacity in the heat-generating machine which arises at low electric power production, a liquid-container serving as heat-accumulator, conduit means including control means being arranged to lead heated liquid, at low electric power production, from the heat-exchanger to the top of the liquid-container and to take out cooler liquid from the bottom of the container, and, at high electric power production, to lead preheated liquid from the preheating stages to the bottom of the liquid-container and to lead hot liquid from the top of the liquid-container to the vaporizing stages, characterized in that the conduit means to the liquid-container are so arranged that, at high electric power production, the liquid-container can be connected in shunt over at least one stage in the evaporation apparatus, and that the heat-exchanger is arranged to raise the temperature of the preheated liquid to such an extent that the difference in temperature between the hot liquid at the top of the container and the cooler liquid at the bottom of the container is equal to the temperature difference between the outlet temperature from the heat-exchanger and the temperature of the water entering the final stage, or some stage before the final stage, in the preheating stages.

Claim 7

A plant for use as a thermal power station operating with variable electric power production in which the excess heat generated at low electric power production is used for vaporizing a liquid in a multi-stage vaporizing arrangement, the plant comprising a heat-generating machine, a turbine driven by this heat-generating machine, an electric generator driven by the turbine, an evaporation apparatus comprising a plurality of stages for vaporizing a liquid and at least one stage for preheating the liquid, a heat-exchanger for additional heating of the pre-heated liquid by means of the excess capacity in the heat-generating machine which arises at low electric power production, a liquid-container serving as heat-accumulator, conduit means including control means being arranged to lead heated liquid, at low electric power production, from the heat-exchanger to the top of the liquid-container and to take out cooler liquid from the bottom of the container, and, at high electric power production, to lead preheated liquid from the preheating stages to the bottom of the liquid-container and to lead hot liquid from the top of the liquid-container to the vaporizing stages, characterized in that the conduit means to the liquid-container are so arranged that, at high electric power production, the liquid-container can be connected in shunt over at least one stage in the evaporation apparatus, and that the heat-exchanger is arranged to raise the temperature of the preheated liquid to such an extent that the difference in temperature between the hot liquid at the top of the container and the cooler liquid at the bottom of the container is equal to the temperature difference between the outlet temperature from the heat-exchanger and the temperature of the water entering the final stage, or some stage before the final stage, in the preheating stages.

Claim 8

A plant according to claim 5, characterized in that the heat-generating machine is a steam-generating machine, that the turbine is a steam-turbine and that conduits are arranged to lead steam from the steam-turbine, preferably its high pressure part, to the heat-exchanger.

Claim 9

A plant according to claim 6, characterized in that the heat-exchanger comprises two stages and that conduits are arranged to lead steam of two different pressures from the turbine to the heat-exchanger.

Claim 10

A plant according to claim 5, characterized in that each vaporizing stage comprises a container in which liquid boils due to pressure reduction, the container comprising a collecting trough for condensate and a supplying means, preferably a spray means, for cooler condensate from the vaporizing stage immediately subsequent, and a conduit to transfer the condensate to the collecting trough in the vaporizing stage immediately preceding, a conduit being arranged to lead the condensate from the first vaporizing stage through the liquid-preheater in heat-exchanging counter-flow to the liquid flowing through the preheating stAges, and a conduit being arranged to return a part of the condensate from the liquid-preheater to the last vaporizing stage.