tcbiomass 2013 Acid Gas and Trace Contaminant … · *Morphysorb Process for syngas cleanup is a patented process . Pilot Plant Location Acid Gas ... Acid Gas Removal Process Flow

Acid Gas and Trace Contaminant

Removal from Synthesis Gas Produced

by Fluidized Bed Gasification of Wood

Using the Morphysorb® Process in the

GTI Flex Fuel Test Facility

Dennis Leppin, P.E.

Gas Technology Institute

Project Objectives

Complete commissioning of Acid Gas Removal (AGR) unit moved to

GTI from Texas in 2007

Integrate AGR with GTI’s Flex Fuel Process configured for Haldor

Topsøe’s TIGAS process

– Converts woody biomass to gasoline via syngas

– Andritz Carbona gasifier used to generate sour syngas

– CO2 concentration in sour syngas must be reduced by the AGR

unit for optimal gasoline synthesis

Provide sweet syngas to downstream gasoline synthesis reactor

– 2 to 5 vol % CO2

– H2S as low as possible

Project Objectives (cont’d.)

Conduct testing with sour syngas to obtain data on Morphysorb* solvent performance such as: Absorption capacity (lb CO2/gallon)

H2, CO and CH4 selectivity

Foaming tendency

Affect of circulation and solvent temperature

System operational limits, e.g., flooding, entrainment, hydraulic

limits

*Morphysorb Process for syngas cleanup is a patented process

Pilot Plant Location

Acid Gas

Removal Unit

(AGR)

Advanced

Gasification Test

Facility (AGTF)

Flex Fuel Test

Facility (FFTF)

GTI Energy & Environmental Technology Campus

Des Plaines, Illinois

Simplified Process Flow Diagram

Gasifier

Tar Reformer

Scrubber

Syngas

Compressor

Morphysorb TIGAS

Off-gas

Gasoline

Water

Wood

pellets

Oxygen,

Steam

Guard Bed Separator

Acid Gas Removal Process Flow Diagram

AGR Equipment Details

12-foot by 12-foot skid mounted unit

~16 in. diameter high pressure absorber

~13 in. diameter stripper

– Both columns have two 20-foot

sections of Sulzer M350Y structured

packing

Natural gas fired re-boiler for stripper

Nitrogen stripping gas

Two 40 gal/min piston pumps for high

pressure solvent circulation

• One is spare

Chilled glycol system to cool lean solvent

to as low as 40 °F

Gas flow measured by orifice plate meters

Solvent flow measured by a turbine meter

Sampling and Analytical Details

Gas Stream Analysis and Sampling

– Sample Points

• Sour Gas

• Sweet Gas

• Flash Gas

• Combined Acid Gas

– Sample Lines

• 1/8” and 1/4”

• Heated and depressurized to 10-40 psig

• Self-regulating, heated and insulated

stainless steel tubing

– Analysis Equipment

• Agilent 490 PRO Micro-GC with two

modules

Sampling and Analytical Details (cont’d.)

• Liquid Stream Sampling and Analysis

– Sample Points

• Rich Solvent (high pressure)

• Flashed Solvent (high pressure)

• Lean Solvent (low pressure)

– High pressure liquids contain dissolved

gases

• Sampled with constant pressure

cylinders

– Low-pressure liquid samples are used to

determine solvent composition and

contamination

NFM NAM

N-formyl morpholine

N-acetyl morpholine

Morphysorb Process

Liquid mixture

– N-formyl morpholine

– N-acetyl morpholine

Physical solvent

– No chemical reaction with acid gas

species.

Patented solvent and process

– Joint property of GTI and Uhde

Applications

– Bulk or trace removal of acid gas components

– Natural gas upgrading to either pipeline or LNG specification

– Generation of H2S stream suitable for Claus plant feed

– Selective removal of H2S, CO2, COS, CS2, mercaptans and other

components from coal, biomass or oil gasification syngas

Selected Results: Gas Composition

Sour Syngas Sweet Syngas

Physical Parameters

Temperature (°F) 67 52

Pressure (psig) ~900 ~900

Flow Rate (lb/h) ~ 2,350 ~900

Composition (vol %)

Carbon Monoxide 25.4 41.6

Carbon Dioxide 40.4 5.1

Hydrogen 27.1 41.2

Methane 3.0 4.7

Nitrogen 4.0 7.3

Selected Results: System Pressures

Selected Results: Gas Flow Rates

Selected Results: Solvent Flow Rate

Selected Results: Absorber Temp Profile

Selected Results: Material Balance

In Out (Out-In)/In

(%)

Total 2,718 2,589 - 4.7

Carbon 720 683 - 5.1

Hydrogen 58 53 - 8.6

Oxygen 1,480 1,389 - 6.1

Selected Results: Overall Performance

316 hours of on-stream operation with biomass-derived sour syngas

Longest continuous on-stream period: 217 hours

Sour syngas feed concentration

CO2: 38 – 43 vol %

H2S : 40 – 50 ppmv

No plant shutdowns due to AGR operations

Acceptable syngas feed provided to downstream TIGAS operations

– CO2 concentration less than ~5 vol%

– H2S reduced to below detectible limits (single digit ppmv level)

Selected Results: Overall Performance

CO2 Absorption (from above Steady State period)

– 1,433 lb/h removed

– 92% removal – 0.95 lb CO2 per gallon solvent circulated

From all mass balance periods

– 1548 to 1827 lb/h CO2 removed

– 88% to 94% CO2 removal

– 0.95 to 1.33 lb CO2 per gallon solvent circulated

– CO2 reduced to as low as 2 vol% in sweet (treated) syngas

Selected Results: H2S Removal

Biomass-derived syngas very low in H2S

– Sour Syngas Feed

• 40 to 50 ppmv H2S

• 0 to 30 ppmv COS

– Sweet Syngas

• H2S below detectible limit of 10 ppmv

• COS 0.5 to 6 ppmv

– Flash Gas

• ~25 to 30 ppmv

– Stripper Offgas (combined)

• 70 to 100 ppmv

80% to 90% H2S balance based on combined acid gas streams

Initial tests did not focus on removal of other trace contaminants

Conclusions

GTI’s AGR system is operational and can be run reliably to support

gasification testing at GTI’s Flex Fuel Test Facility

No foaming, flooding or process upsets observed

Initial testing with Morphysorb solvent indicates it can meet typical

operational specifications for syngas cleanup for chemical synthesis

operations

Morphysorb has promising characteristics of solubility and selectivity

– Future work will compare to state-of-the-art physical solvents

based on dimethyl ether of polyethylene glycol and use feed from

coal gasification operations

Acknowledgements

Illinois Department of Commerce and Economic Opportunity for

funding of the AGR equipment revamp, transfer and commissioning

U.S. D.O.E. & Haldor Topsøe for sponsoring work in biomass

gasification and allowing use of the syngas

Co-authors

– Adam Burkhart

– James Aderhold

– Ajay Makkuni

– Osman Akpolat

GTI operations team

Dr. Olaf v. Morstein and Johannes Menzel of Uhde GmbH for their

technical support