Flash Steam Recovery Using Cascaded Condensate Compression
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Solution Overview
Problem
Industrial processes, such as paper drying, face inefficiencies in utilizing thermal energy from waste steam due to high starting temperatures, leading to high energy consumption and limited thermal energy recovery.
Innovation Solution
A steam supply system that cascades and compresses condensate returns using high and low pressure flash tanks and compressors, integrating a heat pump to recover thermal energy from waste air streams, thereby reducing the need for additional vacuum systems and enhancing energy efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If conventional heat pumps are used to recover thermal energy from waste steam, then thermal energy recovery is limited, but the high starting temperatures of waste steam preclude their use
Solution Approach 1:
The patent changes the temperature parameter of the waste steam by passing it through a heat exchanger that cools it from its original high temperature (e.g., 180°C) to a lower temperature (e.g., below 100°C). This parameter transformation enables the waste steam to become suitable for conventional heat pump recovery, which cannot operate on high-temperature steam directly.
Solution Approach 2:
The patent introduces a heat exchanger as an intermediary device between the waste steam source and the heat pump. This intermediary component facilitates the thermal energy transfer while cooling the waste steam to appropriate temperatures, enabling the heat pump to function effectively without direct exposure to high-temperature steam.
2Reliability
If a thermo-compressor vacuum system operates on steam at 10 Bar(g) and 180 degrees Celsius, then vacuum is generated for the paper making process, but a high amount of energy is consumed
Solution Approach 1:
The patent recovers thermal energy from waste steam and condensate that would otherwise be discarded. By passing waste steam through a heat exchanger and using a heat pump to condense it, the system recovers latent heat and sensible heat, converting waste thermal energy into useful heating or cooling energy, thereby reducing overall energy consumption.
Solution Approach 2:
The patent converts the harmful high-temperature waste steam into a beneficial resource by using it as a heat source for the heat pump system. The waste steam's thermal energy, which would normally be lost, is now utilized to drive the heat pump and provide useful thermal energy for other processes, turning an energy waste stream into an energy asset.
3Reliability
If condensate from the cylinders is passed into a vacuum condenser and flashed steam is condensed at low pressure, then a vacuum is generated, but up to 10% of the steam consumption is accounted for
Solution Approach 1:
The patent recovers both the latent heat and sensible heat from waste steam and condensate through a heat exchanger and heat pump system. This recovery process reduces the need for additional steam generation, thereby decreasing overall steam consumption while maintaining the required vacuum conditions for the paper making process.
Solution Approach 2:
The patent establishes a continuous cycle where waste steam is continuously cooled in the heat exchanger, condensed by the heat pump, and the condensed water is reused. This continuous recovery process ensures sustained vacuum generation while minimizing steam consumption through ongoing thermal energy recycling.
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
The system effectively recovers thermal energy from condensate, reduces energy consumption, and allows steam to be raised at lower temperatures, improving the overall efficiency of steam generation and utilization.
Implementation Method 1
a high pressure flash tank arranged to receive the high pressure condensate return and to generate a flash steam output for the steam process. The steam supply system also comprises a low pressure flash tank arranged to receive the low pressure condensate return and generate a flash steam output
Implementation Method 2
a compressor arranged to compress the flash steam output of the low pressure flash tank and to provide the compressed flash steam to the high pressure flash tank
Implementation Method 3
integrating a heat pump to recover thermal energy from waste air streams
Data Source
AI summary
The present disclosure relates to a steam supply system for supplying steam to a steam process, for example a paper drying system. The steam process has a high pressure condensate return and a low pressure condensate return. The steam supply system has a high pressure flash tank arranged to receive the high pressure condensate return and to generate a flash steam output for the steam process. The steam supply system also includes a low pressure flash tank arranged to receive the low pressure condensate return and generate a flash steam output. The steam supply system also includes a compressor arranged to compress the flash steam output of the low pressure flash tank and to provide the compressed flash steam to the high pressure flash tank.