Ethanol Heat Integration System for Energy Recovery
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Solution Overview
Problem
Existing ethanol production systems require molecular sieve units for dehydration, leading to inefficiencies such as capacity utilization and energy consumption issues due to continuous recycling of ethanol, which increases energy and cooling water requirements.
Innovation Solution
A method and system integrating heat in ethanol production by distilling a feed mixture to form streams that are then processed through molecular sieve units and a separation system, allowing for regeneration and heat exchange to optimize energy recovery and reduce energy consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If molecular sieve units are used for dehydration in ethanol production, then ethanol concentration is increased to 99.0-99.95 vol%, but energy consumption and cooling water requirements increase due to continuous recycling of ethanol
Solution Approach 1:
The patent extracts and removes the regenerate streams from the continuous recycling loop. Instead of recycling the regenerate streams back to the molecular sieve units, the system diverts them to a feed tank for further processing through a separation system. This breaks the continuous recycling cycle that causes energy consumption and cooling water requirements to increase, while still achieving the desired ethanol concentration through the separation system.
Solution Approach 2:
The patent implements periodic action by using a separation system (such as a membrane separation system or distillation system) to periodically process the diverted streams and achieve final ethanol concentration. This replaces the continuous recycling operation with a periodic separation process, reducing the continuous energy input required for recycling while maintaining product quality.
2Manufacturing precision
If molecular sieve units are used for dehydration, then ethanol concentration is increased, but production capacity is limited by the need for continuous recycling
Solution Approach 1:
The patent extracts the regenerate streams from the molecular sieve unit output and removes them from the traditional recycling path. By diverting these streams to a feed tank and subsequent separation system, the patent eliminates the capacity bottleneck created by continuous recycling, allowing the molecular sieve units to operate at full capacity without being constrained by the need to reprocess their own output streams.
Solution Approach 2:
The patent introduces a parallel separation system that copies the dehydration function achieved by molecular sieve units. The separation system (membrane or distillation) provides an alternative pathway to achieve high ethanol concentration, effectively creating a redundant but more efficient processing route that increases overall production capacity without compromising product quality.
3Reliability
If regenerate streams are continuously recirculated, then molecular sieve units maintain dehydration function, but cooling water requirements increase
Solution Approach 1:
The patent extracts the regenerate streams from the continuous recirculation loop and diverts them to a feed tank for processing through a separation system. This removes the source of excessive cooling water requirements while maintaining the dehydration function through the separation system, which can handle the ethanol concentration requirement without the continuous cooling demand of recirculation.
Solution Approach 2:
The patent converts the harmful effect of continuous recirculation (excessive cooling water consumption) into a benefit by directing the regenerate streams to a separation system. The separation system processes these streams to achieve the desired ethanol concentration, and the process can recover energy or reduce cooling demands by integrating with other plant operations or using more efficient separation technology.
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 approach reduces energy and cooling water consumption, increases production capacity by up to 30% without size changes, and stabilizes distillation unit operations by eliminating recirculation of regenerate streams, thereby enhancing overall efficiency and reducing energy costs.
Implementation Method 1
distilling a feed mixture including ethanol and water with one or more distillation units to remove at least a portion of the water
Implementation Method 2
A plurality of molecular sieve units are contacted with a byproduct stream including at least one selected from a portion of the vaporous overhead stream and at least a portion of the fusel oil stream, thereby forming a product stream and one or more regenerate streams
Implementation Method 3
At least one of the plurality of molecular sieve units is regenerated by vacuum or a combination of vacuum and optionally a portion of the product stream to form one or more regenerate streams
Implementation Method 4
Heat is exchanged between at least a portion of the depressure stream and at least one selected from (1) at least a portion of scrubber water streams, (2) at least a portion of the fusel oil stream, (3) at least the condensed portion of the regenerate streams, and (4) at least a portion of the permeate
Implementation Method 5
The feed stream is contacted with a separation system, thereby forming a permeate, a retentate, and a stripper bottom stream
Data Source
AI summary
The present disclosure provides processes and systems for heat integration in ethanol production. In one embodiment, a feed mixture is distilled with one or more distillation units to remove at least a portion of the water, and form a distillation unit bottom stream, a vaporous overhead stream, and a fusel oil stream. Molecular sieve units are regenerated by vacuum or a combination of vacuum and optionally a portion of the product stream to form one or more regenerate streams. A feed tank is configured to receive at least one selected from a condensed portion of the regenerate streams and a portion of a vaporous depressure stream, to form a feed stream. The energy contained in the depressure vapor is recovered by the depressure vapor contacting the feed tank and heating up at least one stream forwarded into the feed tank.