Case Study for Siloxane Removal Case Study for Siloxane Removal Case Study for Siloxane Removal Case Study for Siloxane Removal from Microturbinefrom Microturbinefrom Microturbinefrom Microturbine

SWANApalooza 2017

Jerrel Branson

Pioneer Air Systems LLC

Andrew Greenwood

Flex Energy

THE PROBLEM

HIGH BUILD UP OF SEVERAL SPECIES OF SILOXANES FROM A WASTEWATER ANAEROBIC DIGESTER

MAXIMUM TARGET ALLOWABLE TOTAL SILOXANES OF 0.03mg/m3

Flex Energy GT250

30 GALLONS/YEAR OF SILOXANES

RESULTS OF NON TREATMENT

SOURCES OF SILOXANES

SPECIES SOURCE

L2 antifoaming, antistatic emolient, skin conditioner

L3 skin conditioner

L4 sealants, paint, lacquer, varnish, hydraulic fluid

D3 hair conditioner, emolient, solvents

D4 polishing agent, antistatic, emolient, humictant, etc

D5 dry cleaning fluid, industrial cleaner, car wax

D6 hair conditioner, emolient, solvents

SILOXANES IN BIOGAS

MILLBRAE ANALYSIS

CHARACTERISTICS OF SILOXANES

Mol Wt At 25 C or 77 F

SPECIES G/mol Solubility in Water

Vapor pressure

(psi)

Melting

Point (F)

L2 162.4 930-+ ppb at 73F 0.597555 -88.6

L3 236.5 56 +-ppb at73F 0.075419 -115.6

L4 310.7 6.7 ppb @ 73F 0.010587 -90.4

L5 384.8 7.1 ppb@73F 0.001305 -113.8

D3 222.46 may decompose in water 0.165343 147

D4 296.64 56ppm at 73F 0.018854 63

D5 370.8 17ppb at 73F 0.007251 -47

D6 444.93 .00513 mg/l 0.000435 26.6

PIONEER DCR 8

REMOVAL TECHNOLOGY

Deep Chilling Removal (DCR)precools inlet gas with outlet from system and next stage lowers gas temperature to -10F.

At this temperature remaining moisture freezes and siloxanes andVOCs are ‘captured’ in the ice.

Species and volume of siloxane removed related to solubility, vapor pressure and melting point of species

Siloxanes removed exit through purge of tubes and aqueous streamdischarge

No media involved in process and very low electricity load

POST TREATMENT LAB RESULTS

TREATMENT RESULTS

From 30 gallons/year of siloxanes in microturbine to no buildup after 14 months of operation

Empirical evidence from the lab reports provides assurance of theory

Previously 25% loss of efficiency by the end of the year to no drop in efficiency

Annual outage for generation system may be extended as no drop in efficiency and siloxane build up eliminated at the indicated inlet levels

THOUGHTS

“Non Detect” varies from lab to lab.

Assure lab data accuracy by taking multiple samples prior to finalizing design of equipment

Design for future volumes

THANK YOU