Waste heat recovery ranking cycle system

Patent metadata

Field	Value
Publication number	US-9581050-B2
Application number	US-201314382133-A
Country	US
Kind code	B2
Filing date	Feb 28, 2013
Priority date	Mar 2, 2012
Publication date	Feb 28, 2017
Grant date	Feb 28, 2017

Abstract

A waste heat recovery Rankine cycle system has a first Rankine cycle operated with a first working medium and a second Rankine cycle operated with a second working medium having a lower boiling point than the first working medium, the first Rankine cycle has a second scroll type fluid machine as an expander, a second electric generator, a second condenser, a condensing tank, a second condensing pump, a gas-liquid separation device, a heat exchanger, a low rate regulation valve, and a control device. This structure can drive a generator by a waste heat not only in a first Rankine cycle but also in a second Rankine cycle.

First claim

The invention claimed is:

1. A waste heat recovery Rankine cycle system comprising:
a first Rankine cycle operated with a first working medium; and
a second Rankine cycle operated with a second working medium having lower boiling point than the first working medium,
wherein
the first Rankine cycle has a first condenser in which the first working medium is condensed by the second working medium and a first expander which drives a first generator,
the second Rankine cycle has a condensing pump supplying the second working medium to the first condenser, a regulation valve changing a flow rate of the second working medium, and a gas-liquid separation device which separates the second working medium, heated in the first condenser, into a vapor phase and a liquid phase,
the vapor phase of the second working medium is supplied to a second expander and the liquid phase of the second working medium is supplied to a heat exchanger, wherein the second expander drives a second generator,
a control device is programmed to control such that:
when an amount of heat exchanged between feed water supplied to the heat exchanger and the second working medium is increased, a driving state of the condensing pump and an opening degree of the regulation valve are controlled so as to increase a flow rate of the second working medium, and
when the amount of heat exchanged between the feed water supplied to the heat exchanger and the second working medium is reduced, the driving state of the condensing pump and the opening degree of the regulation valve are controlled so as to reduce the flow rate of the second working medium.

2. The waste heat recovery Rankine cycle system according to claim 1 , further comprising:
a liquid level detection sensor configured to detect a liquid level which is a limit of separation of the vapor phase from the second working medium by the gas-liquid separation device,
wherein the control device is configured such that, when the liquid level detection sensor detects the liquid level, the control device controls the driving state of the condensing pump and the opening degree of the regulation valve so as to increase the flow rate of the second working medium.

3. The waste heat recovery Rankine cycle system according to claim 1 , further comprising:
a second condenser in which the second working medium discharged from the expander is condensed by a cooling water, and
a switching valve which changes a route of the cooling water so as to supply the cooling water instead of the feed water to an instrument to which the feed water is supplied, wherein when an amount of heat exchanged between the feed water and the second working medium per unit flow rate of the feed water is not more than an amount of heat exchanged between the cooling water and the second working medium per unit flow rate of the cooling water in the second condenser, the control device is configured to switch the switching valve so as to supply the cooling water to the instrument to which the feed water is supplied.

Assignees

• Yanmar Co Ltd

Inventors

• Ono Taisuke

Classifications

• F01K25/08

  using special vapours · CPC title

• F01K25/065

  with an absorption fluid remaining at least partly in the liquid state, e.g. water for ammonia (F01K5/00 takes precedence) · CPC title

• F02G5/02

  Profiting from waste heat of exhaust gases · CPC title

• F01K23/04 Primary

  condensation heat from one cycle heating the fluid in another cycle · CPC title

• Y02E20/14

  Combined heat and power generation [CHP] · CPC title