Blowdown Outlet Control for Abrasive Biomass Steam Explosion
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Solution Overview
Problem
Existing thermal hydrolysis processes face issues with scaling, erosion, and blockages due to the use of control valves in blowdown conduits, particularly when processing moist biomass with high dry solids and abrasive content, which are not effectively addressed by prior art solutions.
Innovation Solution
A device with an adjustable open area at the tip of the blowdown conduit regulates the discharge rate, minimizing wear and tear by ensuring the smallest cross-sectional area is at the conduit's end, and using durable materials or deflection plates to manage expansion and erosion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a control valve is located in the blowdown line between the reactor and the pressure relief vessel, then the blowdown rate can be controlled, but the valve and piping are subject to rapid wear, scaling, and blockages due to high-velocity abrasive material
Solution Approach 1:
The invention extracts the control function from the high-wear blowdown line and relocates it to the reactor outlet where conditions are less severe. The control valve is positioned upstream in the reactor outlet piping rather than in the blowdown line itself, separating the control function from the high-velocity abrasive flow path that causes wear and blockages
Solution Approach 2:
The control valve performs the regulation action before the material enters the blowdown conduit. By controlling the discharge rate at the reactor outlet prior to the rapid decompression event, the system prevents abrasive material from reaching high velocities that would cause wear in downstream components
2Productivity
If a nozzle with fixed small cross-sectional area is used at the outlet end of the blowdown conduit, then steam explosion and biomass disintegration are achieved, but the nozzle experiences high wear rate due to rapid decompression occurring before the fluid reaches the deflection plate
Solution Approach 1:
The invention removes the fixed nozzle from the blowdown conduit outlet and replaces it with an adjustable open area device positioned upstream in the reactor outlet piping. This extracts the flow control function from the high-wear zone and allows for adjustment of the opening to optimize performance while reducing wear
Solution Approach 2:
The invention replaces the fixed cross-sectional area nozzle with an adjustable open area device that can be dynamically modified. The adjustable mechanism allows the opening size to be changed based on operational requirements, providing flexibility while positioning the control element in a less severe environment
3Ease of operation
If the adjustable open area is positioned upstream in the blowdown line, then blowdown rate can be regulated, but scaling and blockages occur downstream of the control point due to flash steam drying the material
Solution Approach 1:
The invention extracts the control function from the blowdown line and relocates it to the reactor outlet, removing the source of control from the zone where scaling and blockages occur. By positioning the adjustable open area device upstream in the reactor outlet piping, the control action is separated from the flash steam generation zone
Solution Approach 2:
The adjustable open area device performs flow regulation before the rapid decompression and flash steam generation occur. By controlling the discharge rate upstream in the reactor outlet piping, the system prevents the conditions that lead to scaling and blockages downstream
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 solution effectively mitigates scaling, erosion, and blockages, enabling continuous operation with reduced maintenance costs and improved reliability in both batch and continuous thermal hydrolysis processes.
Implementation Method 1
substrate is first pre-heated from ambient temperature with flash steam resulting from at least one subsequent pressure reduction step... pressure increases up to 2.7-26 bar... the cooked substrate is rapidly discharged through one or more blowdown conduits to a pressure relief vessel
Implementation Method 2
rapid decompression... causing cell destruction and larger bioavailability of the biomass... expansion/spray due to flashing will take place either inside the pressure relief vessel itself
Implementation Method 3
device for controlling steam explosion of biomass in a pressure relief vessel due to large pressure drops over a short time
Data Source
AI summary
The present invention provides a device for controlling steam explosion of biomass having a dry solids content above 1%, a VS content of above 20%, and including abrasive material, in a pressure relief vessel, which includes one or more blowdown conduits having at their outlets an adjustable open area for regulating the blowdown discharge rate. The adjustable open area of each of the one or more blowdown conduits are constructed in such a way that expansion/spray due to flashing takes place either inside the pressure relief vessel itself or in an additional inlet device through which the discharged biomass is directed from the adjustable open area and into the pressure relief vessel and which either have a large enough dimension to avoid the discharged biomass hitting essential parts of the construction or is made from a highly resistant/durable material.