US 10,267,184 B2Granted

Valve network and method for controlling pressure within a supercritical working fluid circuit in a heat engine system with a turbopump

AssigneeEchogen Power Systems, LLC

InventorsBrett A. Bowan, Michael Louis Vermeersch

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Abstract

Aspects of the invention generally provide a heat engine system and a method for activating a turbopump within the heat engine system during a start-up process. The heat engine system utilizes a working fluid circulated within a working fluid circuit for capturing thermal energy. In one exemplary aspect, a start-up process for a turbopump in the heat engine system is provided such that the turbopump achieves self-sustained operation in a supercritical Rankine cycle. Bypass and check valves of a start pump and the turbopump, a drive turbine throttle valve, and other valves, lines, or pumps within the working fluid circuit are controlled during the turbopump start-up process. A process control system may utilize advanced control techniques of the control sequence to provide a successful start-up process of the turbopump without over pressurizing the working fluid circuit or damaging the turbopump via low bearing pressure.

Claims20

Dependent claims

A heat engine system, comprising:

a working fluid circuit having a high pressure side and a low pressure side and containing a working fluid;
a heat exchanger fluidly coupled to and in thermal communication with the high pressure side of the working fluid circuit, configured to be fluidly coupled to and in thermal communication with a heat source stream, and configured to transfer thermal energy from the heat source stream to the working fluid within the high pressure side;
an expander fluidly coupled to the working fluid circuit, disposed between the high pressure side and the low pressure side, and configured to convert a pressure drop in the working fluid to mechanical energy;
a driveshaft coupled to the expander and configured to drive a device with the mechanical energy;
a start pump fluidly coupled to the working fluid circuit, disposed between the low pressure side and the high pressure side, and configured to circulate or pressurize the working fluid within the working fluid circuit;
a start pump bypass valve fluidly coupled to the working fluid circuit, disposed downstream of the start pump, and configured to control the flow of the working fluid flowing into the high pressure side from the start pump;
a turbopump fluidly coupled to the working fluid circuit, disposed between the low pressure side and the high pressure side, and configured to circulate or pressurize the working fluid within the working fluid circuit, wherein the turbopump contains a drive turbine coupled to and configured to drive a pump portion;
a turbopump bypass valve fluidly coupled to the working fluid circuit, disposed downstream of the pump portion of the turbopump, and configured to control the flow of the working fluid flowing into the high pressure side from the pump portion;
a drive turbine throttle valve fluidly coupled to the working fluid circuit, disposed upstream of the drive turbine, and configured to control the flow of the working fluid flowing into the drive turbine;
a recuperator fluidly coupled to the working fluid circuit and configured to transfer thermal energy from the working fluid within the low pressure side to the working fluid within the high pressure side;
a condenser in thermal communication with the working fluid circuit and configured to remove thermal energy from the working fluid in the low pressure side;
and
a process control system operatively connected to the working fluid circuit and configured to adjust the turbopump bypass valve and the start pump bypass valve while providing a turbopump discharge pressure at a greater value than a start pump discharge pressure.

10 more elements

A method for activating a turbopump within a heat engine system during a start-up process, comprising:

circulating a working fluid within a working fluid circuit, wherein the working fluid circuit has a high pressure side and a low pressure side;
transferring thermal energy from a heat source stream to the working fluid by at least one heat exchanger fluidly coupled to and in thermal communication with the high pressure side of the working fluid circuit;
pressurizing a section of an inventory supply line with a transfer pump while maintaining an inventory supply valve in a closed-position, wherein the inventory supply line is fluidly coupled to and between a storage tank and the working fluid circuit;
flowing the working fluid from the high pressure side into a drive turbine of the turbopump, wherein the working fluid has an inlet pressure measured near an inlet of the drive turbine;
flowing the working fluid from a pump portion of the turbopump into the high pressure side, wherein the working fluid as a turbopump discharge pressure measured near an outlet of the pump portion of the turbopump;
detecting a desirable pressure within the section of the inventory supply line and detecting the turbopump discharge pressure equal to or greater than the inlet pressure;
adjusting the inventory supply valve to an opened-position, providing a drive turbine throttle valve in an opened-position, and flowing the working fluid through the inventory supply line, through the working fluid circuit, and into the drive turbine, wherein the drive turbine throttle valve is fluidly coupled to the working fluid circuit upstream of the drive turbine;
and
increasing the turbopump discharge pressure during an acceleration process of the turbopump by:
switching a process controller for a turbopump bypass valve from an automatic mode setting to a manual mode setting;
switching a process controller for a start pump bypass valve from an automatic mode setting to a manual mode setting;
monitoring the turbopump discharge pressure via a process control system operatively connected to the working fluid circuit;
detecting an undesirable value of the turbopump discharge pressure via the process control system, wherein the undesirable value is less than a predetermined threshold value of the turbopump discharge pressure;
adjusting the turbopump bypass valve and the start pump bypass valve with the process control system to increase the turbopump discharge pressure;
detecting a desirable value of the turbopump discharge pressure via the process control system, wherein the desirable value is equal to or greater than the predetermined threshold value of the turbopump discharge pressure;
and
switching the process controllers for the turbopump bypass valve and start pump bypass valve from the manual mode settings to the automatic mode settings.

14 more elements

Dependencies are inferred from the claim text.

Facts

Application: 15/523,441Filed 28 Oct 2015 · us provisional application
Priority: 3 Nov 2014
Published: US 2017/0314420 A12 Nov 2017
Granted: 23 Apr 2019
Term ends: Not estimatedThe source records don’t support an estimate.

Classification11 codes

F01K 13/02
General layout or general methods of operation of complete plants: controlling, e.g. stopping or starting
F01K 7/16
Steam engine plants characterised by the use of specific types of engine ; Plants or engines characterised by their use of special steam…
F01K 11/02
Plants characterised by the engines being structurally combined with boilers or condensers: the engines being turbines
F01K 25/02
Plants or engines characterised by use of special working fluids, not otherwise provided for; Plants operating in closed cycles and not…