Charging pump system for supplying a working fluid to bearings in a supercritical working fluid circuit

Abstract

Provided herein are a heat engine system and a method for generating energy, such as transforming thermal energy into mechanical energy and/or electrical energy. The heat engine system may have a single charging pump for efficiently implementing at least two independent tasks. The charging pump may be utilized to remove working fluid (e.g., CO2) from and/or to add working fluid into a working fluid circuit during inventory control of the working fluid. The charging pump may be utilized to transfer or otherwise deliver the working fluid as a cooling agent to bearings contained within a bearing housing of a system component during a startup process. The heat engine system may also have a mass control tank utilized with the charging pump and configured to receive, store, and distribute the working fluid.

1 . A heat engine system, comprising:
 a working fluid circuit having a high pressure side and a low pressure side and being configured to flow a working fluid therethrough, wherein the working fluid comprises carbon dioxide and at least a portion of the working fluid is in a supercritical state;   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, and configured to transfer thermal energy from the heat source to the working fluid within the high pressure side;   an expander fluidly coupled to the working fluid circuit and 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 system pump fluidly coupled to the working fluid circuit between the low pressure side and the high pressure side of the working fluid circuit and configured to circulate the working fluid through the working fluid circuit;   a recuperator fluidly coupled to the working fluid circuit and operative to transfer thermal energy between the high pressure side and the low pressure side of the working fluid circuit;   a cooler in thermal communication with the working fluid in the low pressure side of the working fluid circuit and configured to remove thermal energy from the working fluid in the low pressure side of the working fluid circuit; and   a mass management system fluidly coupled to the working fluid circuit and comprising:
 a mass control tank fluidly coupled to the low pressure side of the working fluid circuit and configured to receive the working fluid from the working fluid circuit; and 
 a charging pump fluidly coupled to the mass control tank and configured to transfer the working fluid from the mass control tank to:
 the low pressure side of the working fluid circuit by an inventory supply line; and 
 a bearing housing substantially encompassing bearings contained within a system component. 
 
   
     
     
         2 . The heat engine system of  claim 1 , wherein the mass control tank comprises a cryogenic storage vessel. 
     
     
         3 . (canceled) 
     
     
         4 . The heat engine system of  claim 1 , further comprising an inventory return line fluidly coupled to and between the mass control tank and the low pressure side of the working fluid circuit downstream of the condenser. 
     
     
         5 . The heat engine system of  claim 4 , wherein the inventory return line comprises at least one valve configured to control the flow of the working fluid from the low pressure side of the working fluid circuit to the mass control tank. 
     
     
         6 . The heat engine system of  claim 1 , wherein the inventory supply line is fluidly coupled to and between the charging pump and the low pressure side of the working fluid circuit upstream of the system pump. 
     
     
         7 . The heat engine system of  claim 6 , wherein the inventory supply line comprises at least one valve configured to control the flow of the working fluid from the mass control tank, through the charging pump, and to the low pressure side of the working fluid circuit. 
     
     
         8 . The heat engine system of  claim 1 , further comprising a bearing gas supply line fluidly coupled to and between the charging pump and the bearing housing, wherein the bearing gas supply line comprises at least one valve configured to control the flow of the working fluid from the mass control tank, through the charging pump, and to the bearing housing. 
     
     
         9 - 11 . (canceled) 
     
     
         12 . The heat engine system of  claim 1 , wherein the system component comprises the system pump, a turbopump, a turbocompressor, a turboalternator, a power generation system, or other turbomachinery. 
     
     
         13 . The heat engine system of  claim 1 , wherein the system component comprises a power generation system that comprises the expander, a power generator, and the bearing housing substantially encompassing the bearings. 
     
     
         14 . (canceled) 
     
     
         15 . The heat engine system of  claim 1 , wherein the charging pump comprises an electric-motorized pump, a mechanical-motorized pump, or a variable frequency driven pump. 
     
     
         16 . The heat engine system of  claim 1 , further comprising a variable frequency drive coupled to the system pump and configured to control mass flow rate or temperature of the working fluid within the high pressure side of the working fluid circuit. 
     
     
         17 . (canceled) 
     
     
         18 . (canceled) 
     
     
         19 . The heat engine system of  claim 1 , further comprising a turbopump in the working fluid circuit, wherein the turbopump comprises a pump portion coupled to an expansion device. 
     
     
         20 . The heat engine system of  claim 19 , wherein:
 the pump portion of the turbopump is fluidly coupled to the working fluid circuit between the low pressure side and the high pressure side of the working fluid circuit and configured to circulate the working fluid through the working fluid circuit, and   the expansion device of the turbopump is fluidly coupled to the working fluid circuit between the low pressure side and the high pressure side of the working fluid circuit and configured to drive the pump portion by mechanical energy generated by the expansion of the working fluid.   
     
     
         21 . (canceled) 
     
     
         22 . (canceled) 
     
     
         23 . A heat engine system, comprising:
 a working fluid circuit having a high pressure side and a low pressure side and being configured to flow a working fluid therethrough, wherein the working fluid comprises carbon dioxide and at least a portion of the working fluid is in a supercritical state;   a heat exchanger fluidly coupled to and in thermal communication with the working fluid circuit within the high pressure side, configured to be fluidly coupled to and in thermal communication with a heat source, and configured to transfer thermal energy from the heat source to the working fluid within the high pressure side;   an expander fluidly coupled to the working fluid circuit and 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 turbopump comprising a pump portion coupled to an expansion device, wherein the pump portion is fluidly coupled to the working fluid circuit between the low pressure side and the high pressure side and configured to circulate the working fluid through the working fluid circuit, the expansion device is fluidly coupled to the working fluid circuit between the low pressure side and the high pressure side and configured to drive the pump portion by mechanical energy generated by the expansion of the working fluid; and   a mass management system fluidly coupled to the working fluid circuit and comprising:
 a mass control tank fluidly coupled to the working fluid circuit and configured to receive, store, and deliver the working fluid; and 
 a charging pump fluidly coupled to the mass control tank and configured to transfer the working fluid from the mass control tank to:
 the low pressure side of the working fluid circuit; and 
 a bearing housing substantially encompassing bearings contained within the turbopump. 
 
   
     
     
         24 . The heat engine system of  claim 23 , further comprising a recuperator fluidly coupled to the working fluid circuit and operative to transfer thermal energy between the high pressure side and the low pressure side of the working fluid circuit. 
     
     
         25 . The heat engine system of  claim 23 , further comprising a cooler in thermal communication with the working fluid in the low pressure side of the working fluid circuit and configured to remove thermal energy from the working fluid in the low pressure side of the working fluid circuit. 
     
     
         26 . A method for transforming energy with a heat engine system, comprising:
 circulating a working fluid within a working fluid circuit by a system pump, wherein the working fluid circuit has a high pressure side and a low pressure side and at least a portion of the working fluid is in a supercritical state;   transferring thermal energy from a heat source to the working fluid by a heat exchanger fluidly coupled to and in thermal communication with the heat source and the high pressure side of the working fluid circuit;   flowing the working fluid into an expander and converting the thermal energy from the working fluid to mechanical energy of the expander;   flowing a portion of the working fluid from the low pressure side to a mass control tank fluidly coupled to the working fluid circuit and configured to receive, store, and deliver the working fluid;   flowing the working fluid from the mass control tank, through a charging pump, and to:
 a point within the low pressure side of the working fluid circuit upstream of the system pump; and 
 a bearing housing substantially encompassing bearings contained within a system component; 
   wherein the charging pump is fluidly coupled to and disposed downstream of the mass control tank, is fluidly coupled to and disposed upstream of the point within the low pressure side of the working fluid circuit, and is fluidly coupled to and disposed upstream of the bearing housing; and   flowing the working fluid over the bearings disposed within the bearing housing while cooling the bearings.   
     
     
         27 . (canceled) 
     
     
         28 . The method of  claim 26 , further comprising adjusting at least one valve to control the rate of the working fluid flowing from the low pressure side of the working fluid circuit through an inventory return line to the mass control tank. 
     
     
         29 . The method of  claim 26 , further comprising adjusting at least one valve to control the rate of the working fluid flowing from the charging pump through an inventory supply line to the point within the low pressure side of the working fluid circuit. 
     
     
         30 . The method of  claim 26 , further comprising adjusting at least one valve to control the rate of the working fluid flowing from the charging pump through a bearing gas supply line to the bearing housing.