Motor-Compressor System for Acid Gas Cooling

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Solution Overview

Problem

The existing motor-compressor systems for acid gas re-injection face challenges in managing high heat generation by high-speed electric motors and ensuring safe, efficient compression of hazardous acid gas mixtures containing hydrogen sulfide, while also dealing with environmental concerns related to CO2 discharge and sulfur storage.

Innovation Solution

A motor-compressor system where a high-speed electric motor is housed within a pressure vessel, mechanically coupled to compressors, utilizing the acid gas mixture as a coolant to reduce heat and prevent leakage, with a heat exchanger to cool and dehumidify the gas, optimizing temperature and pressure for efficient compression and cooling.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If high-speed electric motors are used to drive compressors for acid gas re-injection, then the necessary head pressure and compression power are achieved, but large amounts of heat are generated that must be managed to prevent damage to the motor and compressor system components

Engineering Contradiction:
Improvecompression powerVSAvoidmotor heat generation
Core Design Contradiction:
PowerVSTemperature

Solution Approach 1:

The patent combines the motor cooling function with the acid gas compression process by using the acid gas itself as the cooling medium. The acid gas flows through the motor housing and compressor inter-stage, absorbing heat from both components simultaneously, thereby merging the cooling function with the compression process rather than requiring separate cooling systems.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The acid gas serves a dual purpose: it is both the process gas being compressed and the cooling medium for the motor and compressor. The system uses its own process gas to cool itself, eliminating the need for external cooling systems and reducing overall system complexity while managing heat generation effectively.

Inventive Principle:
Principle #25Self-service

2Temperature

If process gas is used to cool the high-speed electric motor, then cooling is achieved, but the efficiency suffers due to windage losses

Engineering Contradiction:
Improvemotor coolingVSAvoidwindage losses
Core Design Contradiction:
TemperatureVSLoss of energy

Solution Approach 1:

The patent directs the cooled acid gas specifically to areas of high heat generation within the motor and compressor, such as the motor housing and inter-stage regions. This localized cooling approach targets critical hot spots without requiring the entire gas flow to be used for cooling, thereby reducing windage losses while maintaining effective cooling where it is most needed.

Inventive Principle:
Principle #3Local quality

3Stress or pressure

If multi-stage centrifugal compressors are used to achieve operating pressures of 100 to 200 bars, then the necessary head pressure for re-injection is achieved, but high power requirements and heat generation increase

Engineering Contradiction:
Improvehead pressureVSAvoidpower consumption
Core Design Contradiction:
Stress or pressureVSPower

Solution Approach 1:

The patent maintains continuous cooling of the motor and compressor throughout the compression process by circulating acid gas through the motor housing and inter-stage regions. This continuous cooling prevents temperature buildup that would reduce compression efficiency and increase power consumption, thereby maintaining optimal operating conditions throughout the multi-stage compression process to achieve 100-200 bars pressure.

Inventive Principle:
Principle #20Continuity of useful action

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This configuration enhances cooling efficiency, reduces reliance on external cooling systems, minimizes gas leakage, and effectively manages the corrosive nature of acid gas, enabling safe and efficient compression of acid gas mixtures for re-injection while reducing environmental impact.

Implementation Method 1

a first portion of the cooled compressed gas mixture is contacted with a first electric motor disposed within the pressure vessel and mechanically coupled to the first compressor

Methodology Applied
Scientific EffectConvection: Convection

Implementation Method 2

with a heat exchanger to cool and dehumidify the gas, optimizing temperature and pressure for efficient compression and cooling

Methodology Applied
Scientific EffectHeat exchange: Heat Exchanger

Data Source

PatentEP2402614B1Method And Apparatus For Acid Gas Compression
Publication Date: 2017.12.13 GENERAL ELECTRIC CO
  • EP2402614B1 patent drawingFigure 1
  • EP2402614B1 patent drawingFigure 2
  • EP2402614B1 patent drawingFigure 3

AI summary

The present invention provides novel motor-compressor systems and methods useful for handling acid gas, by-produced produced in large quantities from natural gas refining. In one embodiment, a novel motor-compressor system comprises first compressor; a pressure vessel configured to receive a compressed gas from the first compressor; a heat exchanger coupled to the pressure vessel configured to cool the compressed gas and provide a cooled compressed gas; and an electric motor housed within the pressure vessel, wherein the electric motor is mechanically coupled to the first compressor, and wherein the pressure vessel is configured to receive at least a portion of the cooled compressed gas from the heat exchanger and contact the electric motor. The methods and systems described herein are particularly useful in acid gas re-injection operations where large quantities of acid gas are subjected to compression at high pressure and leakage prevention is critical.