Continuous Ligno-Cellulosic Pretreatment via Dual Steam Injection
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Solution Overview
Problem
Steam explosion processes for ligno-cellulosic feedstock pretreatment require large amounts of steam and result in significant condensed liquid water, leading to inefficiencies and potential plugging issues, while existing solutions either require excessive mechanical energy or are difficult to scale industrially.
Innovation Solution
A continuous process involving a pressurized reactor where two steam streams with different temperatures are used for hydrothermal treatment, with superheated steam to reduce steam consumption and condensed water, and a steam explosion device for rapid pressure release, optimizing steam usage and process efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If large amounts of steam are used for hydrothermal treatment, then the feedstock is effectively heated and steam exploded, but steam consumption and energy consumption increase significantly
Solution Approach 1:
The feedstock is pre-heated in a heat exchanger before entering the reactor, so that when steam is injected, less steam is needed to reach the required temperature for effective steam explosion. This preliminary heating action reduces the total steam consumption while maintaining explosion effectiveness.
Solution Approach 2:
The invention changes the temperature parameter of the feedstock before steam injection by using a heat exchanger to pre-heat the feedstock. This parameter change allows the steam explosion to occur more efficiently with reduced steam input, as the feedstock is already at an elevated temperature when the steam is introduced.
2Reliability
If steam is used to heat the feedstock to high temperature, then the steam explosion is effective, but condensed liquid water is produced in large quantities causing plugging of blow lines
Solution Approach 1:
The feedstock is pre-heated in a heat exchanger before steam injection, which reduces the amount of steam needed and consequently reduces the amount of condensed water produced during the steam explosion. This preliminary action prevents blow line plugging while maintaining explosion effectiveness.
Solution Approach 2:
The invention uses a heat exchanger to pre-heat the feedstock, which converts the potential harm of excessive steam condensation into a benefit by reducing the total steam required. The pre-heating process eliminates the need for large steam volumes that would otherwise condense and cause plugging.
3Reliability
If mechanical energy is applied to increase pressure of feed material stream, then steam explosion effectiveness is improved, but mechanical energy consumption increases
Solution Approach 1:
The invention replaces the mechanical compression system with a thermal approach. Instead of using a compressor to mechanically increase the pressure of the feed material stream, the system uses a heat exchanger to pre-heat the feedstock, which allows steam to be injected more effectively without requiring additional mechanical energy input.
Solution Approach 2:
The heat exchanger acts as an intermediary between the feedstock and the steam injection system. It transfers thermal energy to the feedstock before steam is introduced, enabling the steam explosion to occur more effectively without requiring mechanical compression of the feed material stream.
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 significantly reduces steam consumption and condensed water, maintaining process effectiveness while preventing pressure drops and plugging, enabling a more efficient and scalable pretreatment method.
Implementation Method 1
hydrothermally treating the ligno-cellulosic feedstock with steam at a reactor pressure, by inserting at least a first steam stream comprising a first steam
Implementation Method 2
a second steam stream comprising a second steam in the pressurized reactor vessel, the second steam having a second steam temperature greater than the first steam temperature
Implementation Method 3
steam exploding the ligno-cellulosic feedstock
Data Source
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AI summary
It is disclosed a continuous process for pre-treating a ligno-cellulosic feedstock. The ligno-cellulosic feedstock is introduced in a pressurized reactor vessel and subjected to a hydrothermal treatment with steam by inserting steam from at least a two steam streams having different temperatures. The ligno-cellulosic feedstock is then subjected to steam explosion. Preferably, at least a portion of the steam in the reactor is superheated steam and the superheated steam is located in a superheated zone which is in proximity of the outlet of the pressurized reactor vessel.