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US 7,243,618 B2Granted
Steam generator with hybrid circulation
OwnerArkadiy M. Gurevichinventor
Life of this patent
Estimating the term…
Abstract
A hybrid vapor generator has at least one evaporator with tubes arranged in sections, one section including a natural circulation loop with a separating drum and downcomer(s), and another section being a pump assisted once-through circulation section.
Claims18
A steam generator, comprising:
- a steam separating drum having a drum water inlet and a drum steam outlet, said drum steam outlet operating at a first pressure;
- at least one evaporator including at least two evaporator sections, each of said evaporator sections including a plurality of heat-absorbing steam generating tubes connected in parallel;
- at least one of said evaporator sections comprising a natural circulation section, which receives water from said drum and outputs a steam water mixture into said drum;
- at least another of said evaporator sections comprising a once-through section, having an evaporator inlet and an evaporator outlet that outputs steam at said first pressure;
- a feedwater pump having an outlet that splits into at least a first feed line which feeds the drum and at least a second feed line which feeds the once-through evaporator section;
- and
- a control system including at least two feedwater control valves, one of said feedwater control valves in said first feed line, controlling the flow of water from said feedwater pump to said drum water inlet, and the other of said feedwater control valves in said second feed line, independently controlling the flow of water from said feedwater pump to said evaporator inlet for said once-through section.
4 more elements
A method of steam generation, comprising the steps of:
- providing an evaporator including at least two parallel steam generating sections, each including a plurality of heat-absorbing evaporator tubes connected in parallel, one of said sections being a natural circulation section including a steam separating drum, and another of said sections being a once-through section;
- pumping feedwater in parallel flow to said drum and to said once-through section;
- combining the steam outputs from said natural circulation section and from said once-through section into a common steam supply line;
- and
- controlling the water level in said drum and the superheated steam temperature downstream of said evaporator sections by controlling the parallel feedwater flows to said drum and to said once-through section, respectively.
2 more elements
A hybrid vapor generator, comprising:
- a hot gas duct;
- an evaporator operating at a single outlet pressure, said evaporator including a plurality of evaporator sections, at least one of said evaporator sections being a natural circulation section, including a separating drum, a downcomer, a plurality of natural circulation heat absorbing evaporator tubes located inside said hot gas duct and connected together in parallel, and a riser;
- and at least another of said evaporator sections being a pump assisted circulation section including a plurality of pump assisted circulation heat absorbing evaporator tubes connected together in parallel;
- and
- a pump, which pumps working fluid into said pump assisted circulation evaporator section through at least a first inlet line;
- wherein said pump assisted circulation evaporator section is a once-through evaporator section, and said drum is fed through at least a second inlet line which is connected in parallel with said first inlet line.
3 more elements
Dependencies are inferred from the claim text.