Pressure reducing system and method for using the same

A method for reducing high pressure gas in a transmission pipeline to low pressure gas in a consumer pipeline, said method comprising the steps of:

• a) expanding said high pressure gas in an expander interposed between the transmission pipeline and the consumer pipeline for producing work and low pressure gas that is supplied to said consumer pipeline;
• b) converting work produced by said expander into electrical power which is supplied to an electrical load;
• c) sensing the volumetric flow through said expander;
• and
• d) shunting said expander with a selectively adjustable pressure regulator valve system only after the volumetric flow through said expander decreases below a predetermined threshold.

An energy recovery, pressure reducing system for reducing high pressure gas in a transmission pipeline to a low pressure gas in a consumer pipeline, said system comprising:

• a) a primary pressure regulating valve having an adjustable flow control opening, and selectively connectable between the transmission and consumer pipelines for throttling the high pressure gas and producing low pressure gas when said primary pressure regulating valve is connected between said pipelines;
• b) a bypass line shunting said primary pressure regulating valve for connecting said pipelines when said primary pressure regulating valve is disconnected from said pipelines, said bypass line including an expander system having at least one expander for expanding said high pressure gas and producing work and low pressure gas that is supplied to said consumer pipeline, and a generator coupled to said expander for converting said work to electricity which is supplied to an electrical load;
• c) fast acting, selectively adjustable, pressure regulating valve apparatus connected in parallel with said expander system, said apparatus having an operational state in which high pressure gas from said transmission pipeline is throttled to said low pressure and transmitted to said consumer pipeline, and a non-operational state in which no gas is transmitted;
• and
• d) a control system responsive to a reduction in flow through said expander system below a threshold for rapidly switching said apparatus from said non-operational state to said operational state.

An energy recovery, pressure reducing system for reducing high pressure gas in a transmission pipeline to a low pressure gas in a consumer pipeline, said system comprising:

• a) a primary pressure regulating valve having an adjustable flow control opening, and connectable between the transmission and consumer pipelines for throttling the high pressure gas and producing low pressure gas when said primary pressure regulating valve is connected between said pipelines;
• b) a bypass line shunting said primary pressure regulating valve for connecting said pipelines when said primary pressure regulating valve is disconnected from said pipelines, said bypass line including an expander system having at least one expander for expanding said high pressure gas and producing work and low pressure gas that is supplied to said consumer pipeline;
• c) fast acting, selectively adjustable, pressure regulating valve apparatus connected in parallel with said expander system, said apparatus having an operational state in which high pressure gas from said transmission pipeline is throttled to said low pressure and transmitted to said consumer pipeline, and a non-operational state in which no gas is transmitted;
• and
• d) a control system responsive to a reduction in flow through said expander system below a threshold for rapidly switching said apparatus from said non-operational state to said operational state.

An energy recovery, pressure reducing system for reducing high pressure gas in a transmission pipeline to a low pressure gas in a consumer pipeline, said system comprising:

• a) a primary pressure regulator valve having an adjustable flow control opening, and selectively connectable between the transmission and consumer pipelines for throttling the high pressure gas and producing low pressure gas when said primary pressure regulating valve is connected between said pipelines;
• b) a bypass line shunting said primary pressure regulator valve for connecting said pipelines when said primary pressure regulating valve is disconnected from said pipelines, said bypass line including an expander system having at least one expander for expanding said high pressure gas and producing work and low pressure gas that is supplied to said consumer pipeline, and a generator coupled to said expander for converting said work to electricity which is supplied to an electrical load;
• c) fast acting, selectively adjustable, pressure regulating valve apparatus connected in parallel with said expander system, said apparatus having an operational state in which high pressure gas from said transmission pipeline is throttled to said low pressure and transmitted to said consumer pipeline, and a non-operational state in which no gas is transmitted;
• and
• d) a control system responsive to a reduction in flow through said expander system below a threshold for rapidly switching said apparatus from said non-operational state to said operational state.

An energy recovery, pressure reducing system for reducing high pressure gas in a transmission pipeline to a low pressure gas in a consumer pipeline, said system comprising:

• a) a primary pressure regulator valve having an adjustable flow control opening, and connectable between the transmission and consumer pipelines for throttling the high pressure gas and producing low pressure gas when said primary pressure regulating valve is connected between said pipelines;
• b) a bypass line shunting said primary pressure regulating valve for connecting said pipelines when said primary pressure regulating valve is disconnected from said pipelines, said bypass line including an expander system having at least one expander for expanding said high pressure gas and producing work and low pressure gas that is supplied to said consumer pipeline;
• c) fast acting, selectively adjustable, pressure regulator or regulating valve apparatus connected in parallel with said expander system, said apparatus having an operational state in which high pressure gas from said transmission pipeline is throttled to said low pressure and transmitted to said consumer pipeline, and a non-operational state in which no gas is transmitted;
• and
• d) a control system responsive to a reduction in flow through said expander system below a threshold for rapidly switching said apparatus from said non-operational state to said operational state.

An energy recovery, pressure reducing system for reducing high pressure gas in a transmission pipeline to a low pressure gas in a consumer pipeline, said system comprising:

• a) an expander system having at least one expander for expanding said high pressure gas and producing work and low pressure gas that is supplied to said consumer pipeline;
• b) apparatus including an on/off valve serially connected to a pressure regulating valve, said apparatus being connected in parallel with said expander system;
• c) said on/off valve having an open state for effecting transmission of gas through said pressure regulating valve, and a closed state for preventing transmission of gas through said pressure regulating valve, and said pressure regulating valve having an adjustable flow control opening for throttling high pressure gas and producing low pressure gas when said on/off valve is in its open state;
• and
• d) a control system responsive to flow through said expander system for controlling the size of said flow control opening and the state of said on/off valve.

An energy recovery, pressure reducing system for reducing high pressure gas in a transmission pipeline to a low pressure gas in a consumer pipeline, said system comprising:

• a) an expander system having at least one expander for expanding said high pressure gas and producing work and low pressure gas that is supplied to said consumer pipeline, and a generator coupled to said expander for converting said work to electricity which is supplied to an electrical load;
• b) apparatus connected in parallel with said expander system;
• and
• c) means for rapidly switching flow from said expander system to said apparatus in response to a reduction below a threshold in flow through said expander system;
• d) said apparatus including means for minimizing the production of shock waves in the transmission and consumer pipelines due to said switching.

An energy recovery, pressure reducing system for reducing high pressure gas in a transmission pipeline to a low pressure gas in a consumer pipeline, said system comprising:

• a) an expander system having at least one expander for expanding said high pressure gas and producing work and low pressure gas that is supplied to said consumer pipeline, and a generator coupled to said expander for converting said work to electricity which is supplied to an electrical load;
• b) apparatus including an on/off valve serially connected to a pressure regulating valve, said apparatus being connected in parallel with said expander system;
• c) said on/off valve having an open state for effecting transmission of gas through said pressure regulating valve, and a closed state for preventing transmission of gas through said pressure regulating valve, and said pressure regulating valve having an adjustable flow control opening for throttling high pressure gas and producing low pressure gas when said on/off valve is in its open state;
• and
• d) a control system responsive to flow through said expander system for controlling the size of said flow control opening and the state of said on/off valve.

Apparatus for reducing high pressure gas in a transmission pipeline to low pressure gas in a consumer pipeline, said apparatus comprising:

• a) an expander selectively connectable between the transmission pipeline and the consumer pipeline for producing work and low pressure gas that is supplied to said consumer pipeline;
• b) a sensor for sensing the volumetric flow through said expander;
• and
• c) a shunt selectively connectable between the transmission pipeline and the consumer pipeline, and including a selectively adjustable pressure regulator valve;
• and
• d) means responsive to said sensor for either connecting only said expander between the transmission pipeline and the consumer pipeline, or connecting only said shunt between the transmission pipeline and the consumer pipeline.