Multi-Compressor String With Multiple Variable Speed Fluid Drives

A method for starting a string of rotating power equipment including a prime mover driving multiple compressors, and multiple variable speed fluid torque converters for starting at least a first of said compressors followed by other torque converters starting other compressors, in succession, said prime mover being connected to a first variable speed fluid drive torque converter, and said first torque converter being connected to said first compressor, and at least a second torque converter being connected to said first compressor and in turn connected to a second of said compressors, each of said torque converters providing an output from zero to full speed, the method comprising:

• starting the prime mover and bringing it to full speed;
• starting said first compressor by increasing the output speed of said first torque converter to full speed;
• and
• starting said second compressor by increasing the output speed of said at least second torque converter to full speed,
• whereby the power necessary to start each compressor is supplied successively and in turn by each torque converter.

A method of cooling the working fluid of multiple variable speed hydraulic torque converters in a string of rotating power equipment including a prime mover driving multiple compressors, and multiple variable speed fluid torque converters for starting at least one of said compressors followed by other torque converters starting other compressors, in succession, said prime mover being connected to a first variable speed fluid drive torque converter, and said first torque converter being connected to a first compressor, and at least a second torque converter connected to said first compressor and in turn connected to a second of said compressors, each of said torque converters providing an output from zero to full speed, each of said torque converters including a supply conduit for cooled working fluid, and a discharge conduit for the heated working fluid, said supply conduit and said discharge conduit for each of said torque converters being connected to a single heat exchanger, and including a discharge valve in each of said discharge conduits and a supply valve in each of said supply conduits, wherein the method comprises:

• starting the prime mover;
• opening the supply and discharge valves of said first torque converter while keeping all other valves to said second torque converter closed to permit the working fluid to flow through said first converter and said single heat exchanger;
• starting said first compressor and increasing the speed up to full speed;
• closing the supply and discharge valves to said first torque converter;
• opening the supply and discharge valves to said second torque converter while keeping all other valves closed to permit the working fluid to flow through said second torque converter and said single heat exchanger;
• starting said second compressor and increasing its speed to full speed;
• and
• closing the supply and discharge valves to said second torque converter, whereby each of said torque converters can be successively isolated from said single heat exchanger in turn.

A compressor starting arrangement for a string of rotating equipment, the string including a turbine or motor, and a plurality of pressurized compressors to be driven by one of said turbine or motor, the arrangement comprising:

• a starter motor and a hydraulic clutch for initiating operation of said one of, a turbine or a motor;
• a first variable speed fluid drive torque converter interposed in said string after said one of, a turbine or a motor, and before a first compressor;
• a second variable speed fluid drive torque converter interposed in said string before a second compressor;
• a third variable speed fluid drive torque converter interposed in said string before a third compressor;
• a fourth variable speed fluid drive torque converter interposed in said string before a fourth compressor;
• each of said variable speed fluid drive torque converters comprising a compressor starting torque converter that uses a working fluid to transmit power from zero output to a lock-up speed at which point the input speed is synchronized to output speed and a torque converter lock up device is engaged and the power is transmitted mechanically;
• a single heat exchanger including an external supply of cooling fluid;
• a pump for circulating said working fluid through said heat exchanger;
• each of said torque converters including a supply conduit for cooled working fluid, and a discharge conduit for the heated working fluid;
• a cold manifold being connected to receive cooled working fluid from said heat exchanger, and wherein said supply conduits for each of said variable speed torque converters are connected to said cold manifold;
• a hot manifold being connected to said heat exchanger, and wherein said discharge conduits for each of said plurality of torque converters are connected to said hot manifold;
• a discharge valve in each of said discharge conduits, whereby the working fluid discharged form each of said torque converters can be isolated from said single heat exchanger;
• and
• a supply valve in each of said supply conduits, whereby each of said torque converters can be isolated from the cooled working fluid from said single heat exchanger,
• whereby said compressors are started by said variable speed fluid drive torque converters successively and in turn, and the working fluid for multiple torque converters is cooled by a single heat exchanger.

A method for manufacturing liquefied natural gas using rotating power equipment including a prime mover driving multiple compressors, said compressors compressing a refrigerant, said compressed refrigerant being used to cool natural gas to a liquid state, and multiple variable speed fluid torque converters for starting at least a first of said compressors followed by other torque converters starting other compressors, in succession, said prime mover being connected to a first variable speed fluid drive torque converter, and said first torque converter being connected to said first compressor, and at least a second torque converter being connected to said first compressor and in turn connected to a second of said compressors, each of said torque converters providing an output from zero to full speed, said method comprising:

• starting the prime mover and bringing it to full speed;
• starting said first compressor by increasing the output speed of said first torque converter to full speed;
• and
• starting said second compressor by increasing the output speed of said at least second torque converter to full speed,
• whereby the power necessary to start each compressor is supplied successively and in turn by each torque converter.