Level and Flow Applications for Biomass Gasifier Skid Systems

More and more owner/operators, OEMs and plant engineers throughout the process industry are fabricating their unit operations as modular skid systems. This post discusses instrumentation for biomass gasifier skid systems and is part of an occasional Magnetrol® blog series on level and flow control for skid system applications.

Biomass is cultivated and waste forms of biological material, including: crops, forest residue, waste from livestock, food processing, and municipal sources. When biomass is heated in the absence of oxygen, it decomposes into a mixture of hydrogen and carbon monoxide gases known as synthesis gas or “syngas”. Like natural gas, syngas is a valuable energy asset that can fuel boilers, generators, and furnaces, or serve as a feedstock.

BioMass-to-Syngas Skid

In this entrained-flow type of gasifier, the steam and oxygen reactants flow uni-directionally upwards through the gasifier until high temperature finished syngas exits the reactor.

The biomass feedstock enters the gasifier for conversion into synthesis gas. The syngas exits the gasifier and is routed to a gas cooler to recover useable thermal energy. The gas is then cleaned and routed to an application or to storage.

Level and Flow Applications

biomass_gasifier

1.Hopper Level Solid biomass feedstock is ground into small particles and fed into a biomass hopper from where it is conveyed to the gasifier. High and low level detection in the hopper maintains correct hopper level.
Continuous Level: Eclipse® Model 706 Guided Wave Radar Transmitter

2. Input Air Flow Many gasification systems use nearly pure oxygen to facilitate the reaction in the gasifier. Typically, the oxygen is generated in an off-skid plant using cryogenic technology. The oxygen flow is monitored by mass flow transmitters.
Continuous Gas Flow: Thermatel® Model TA2 Thermal Dispersion Mass Flow Meter

3. Gas Cooler The raw syngas leaving the gasifier enters a gas cooling unit to reduce the gas’s temperature. Level controls monitoring the coolant within the cooler body serve as a leak detection system for the gas cooler.
Continuous Level: ECLIPSE Model 706 Guided Wave Radar Transmitter
Point Level: Model B35 External Cage Float Switch or Echotel® Model 961 Ultrasonic Switch

4. Scrubbers Impurities in the syngas—including trace minerals, particulates, sulfur, mercury, and unconverted carbon—are reduced to very low levels by using gas scrubbers. Accurate level monitoring maintains correct amounts of scrubber make-up water.
Continuous Level: ECLIPSE Model 706 Guided Wave Radar Transmitter
Point Level: Model B35 External Cage Float Level Switch or ECHOTEL Model 961 Ultrasonic Switch

5. Output Syngas Flow
Clean syngas is routed to storage or to its application, including: fuel for heat or electricity generation, or to serve as a chemical or petrochemical feedstock. The mass flow of the syngas is monitored by a mass flow transmitter.
Continuous Gas Flow: THERMATEL Model TA2 Thermal Dispersion Mass Flow Meter

modular_skid_systems

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