Gas recovery system for compressor, compressor system, and refrigeration cycle system

Patent metadata

Field	Value
Publication number	US-11067320-B2
Application number	US-201515538436-A
Country	US
Kind code	B2
Filing date	Mar 25, 2015
Priority date	Dec 26, 2014
Publication date	Jul 20, 2021
Grant date	Jul 20, 2021

Abstract

A gas recovery system for a compressor, said gas recovery system being equipped with: a distillation column that brings a supply gas in a liquid state into contact with a mixed gas, thereby cooling and liquefying a process gas in the mixed gas, and heating and gasifying the liquid supply gas; a process gas recovery line that is connected to the lower part of the distillation column and recovers the liquid process gas discharged from the distillation column; and a supply gas recovery line that is connected to the upper part of the distillation column and recovers the gaseous supply gas discharged from the distillation column.

First claim

The invention claimed is:

1. A refrigeration cycle system comprising:
a compressor which compresses refrigerant process gas in a gas state;
a seal portion which is provided in each of gaps between a stator and a rotor in both the end portions of a rotary shaft, and to which a separation gas in a gas state is supplied thereby preventing lubricating oil used in a bearing from being mixed into the seal portion;
a condenser which condenses and liquefies the refrigerant process gas, which has been compressed by the compressor, in a gas state;
a valve which adiabatically expands the refrigerant process gas, which has been condensed by the condenser, in a liquid state;
an evaporator which exchanges heat between the refrigerant process gas, which has been adiabatically expanded by the valve, in a liquid state and a target to be cooled, thereby cooling the target and evaporating the refrigerant process gas in a liquid state; and
a gas recovery system for the compressor that recovers mixed gas, wherein the mixed gas is a mixture of the refrigerant process gas which is compressed by the compressor and leaked into the seal portion and the separation gas in a gas state which is supplied to the seal portion of the compressor, from the seal portion, and separates the mixed gas into the refrigerant process gas and the separation gas in a gas state,
wherein the gas recovery system comprises:
a distillation column that brings the separation gas in a liquid state into contact with the mixed gas, thereby exchanging heat between the mixed gas and the separation gas in a liquid state to cool and liquefy the refrigerant process gas contained in the mixed gas, and heat and gasify the separation gas in a liquid state;
a process gas recovery line that is connected to a lower part of the distillation column and recovers the refrigerant process gas in a liquid state discharged from the lower part of the distillation column, the refrigerant process gas recovered through the process gas recovery line being supplied to the compressor; and
a supply gas recovery line that is connected to an upper part of the distillation column and recovers the separation gas in a gas state discharged from the upper part of the distillation column, the separation gas in a gas state being recovered through the supply gas recovery line and being supplied to the seal portion,
wherein the gas recovery system further comprises:
a process gas circulation line that branches from the process gas recovery line and returns the refrigerant process gas in a liquid state, which is discharged from the distillation column, to the distillation column after being gasified;
a supply gas circulation line that branches from the supply gas recovery line and returns the separation gas in a gas state, which is discharged from the distillation column, to the distillation column after being liquefied; and
a circulation heat exchanger that exchanges heat between the refrigerant process gas in a liquid state flowing through the process gas circulation line and the separation gas in a gas state flowing through the supply gas circulation line,
the separation gas in a gas state contained in the mixed gas in the distillation column is maintained in a gas state, and with the separation gas in a liquid state is heated and gasified by the refrigerant process gas contained in the mixed gas.

2. The refrigeration cycle system according to claim 1 , wherein the refrigerant process gas is Freon or hydrocarbon, and the separation gas in a gas state is carbon dioxide or hydrocarbon.

3. The refrigeration cycle system according to claim 1 , further comprising:
a mixed gas supply line that is connected to the distillation column and supplies the mixed gas to the distillation column; and
a mixed gas heat exchanger that exchanges heat between the refrigerant process gas flowing through the process gas recovery line and the mixed gas flowing through the mixed gas supply line, thereby cooling the mixed gas with the refrigerant process gas flowing through the process gas recovery line.

4. The refrigeration cycle system according to claim 3 , further comprising:
an additional supply line for additionally supplying the refrigerant process gas in a liquid state to the process gas recovery line, between the distillation column and the mixed gas heat exchanger.

5. The refrigeration cycle system according to claim 4 , wherein the mixed gas heat exchanger exchanges heat between the separation gas flowing through the supply gas recovery line and the mixed gas flowing through the mixed gas supply line, thereby cooling the mixed gas with the separation gas flowing through the supply gas recovery line.

6. The refrigeration cycle system according to claim 1 , wherein the seal portion includes a dry gas seal, and a separation seal installed between a bearing of the compressor and the dry gas seal.

7. The refrigeration cycle system according to claim 6 , further comprising:
a second distillation column that brings the separation gas in a liquid state into a second mixed gas in which the separation gas is mixed with lubricating oil from the bearing of the compressor, thereby exchanging heat between the second mixed gas and the liquid separation gas to cool and liquefy the lubricating oil contained in the second mixed gas, and heat and gasify the liquid separation gas; and
a second supply gas recovery line that is connected to an upper part of the second distillation column and recovers the separation gas in a gas state discharged from the upper part of the distillation column.

8. The refrigeration cycle system according to claim 1 , wherein the seal portion includes a plurality of dry gas seals, and the separation supply gas is a seal gas supplied between the dry gas seals adjacent to each other.

9. The refrigeration cycle system according to claim 1 , further comprising:
a circulation compressor which raises the pressure of the separation gas, which has been drawn into the distillation column upper circulation line from the supply gas recovery line, in a gas state, and
a circulation valve which adiabatically expands the gaseous separation supply gas flowing through the distillation column upper circulation line.

Assignees

• Mitsubishi Heavy Ind Compressor Corp

Inventors

• Watanabe Takuya
• Mizushita Koichi
• Takeda Tomoaki
• Mori Yasushi

Classifications

• F04D29/124 Primary

  with special means for adducting cooling or sealing fluid · CPC title

• F25J2260/20

  Integration in an installation for liquefying or solidifying a fluid stream · CPC title

• F25J2270/02

  Internal refrigeration with liquid vaporising loop · CPC title

• F25J3/0238

  separation of CnHm with 2 carbon atoms or more · CPC title

• F25J1/025

  Details related to the refrigerant production or treatment, e.g. make-up supply from feed gas itself · CPC title