Annular Flow at 80% Steam Quality
Increasing OTSG Steam Quality While Operating on Conventionally Treated BFW Albert Mansour, MBA, PMP, B.A.Sc.
Once Through Steam Generator (OTSG)
Boiler eedwater (BFW) Radiant Section
Convective Section Dry Steam
75% - 80% Wet Steam Quality (Typical)
Separator (SAGD)
Blowdown (Wet Steam Water Content)
Limits to Higher Steam Quality • Typical OTSG radiant section piping is smooth
• Radiant pipe operates under annular flow regime • Annular flow is a dispersion of water on the pipe surface with entrained droplets in the core steam flow
Annular flow regime
Limits to Higher Steam Quality • Traditional OTSG steam quality limits are between 75% and 80%
• BFW impurities concentrate in remaining water before exiting OTSG • At higher steam qualities, smooth pipes have low water quantity on the pipe surface • Operation above 80% may lead to scale deposit formation due to dry spots • Deposits can lead to pipe overheating and failure
Annular Flow at 80% Steam Quality
Pipe Wall
Higher Concentration Impurities (Thicker Bottom Film)
Lower Concentrated Entrained Droplets (Non-Uniform Impurity Concentrations) Surface Water Film Layer
Solutions to Achieving Higher Steam Quality – SQ90TM • Utilizing modified (rifled) piping in select radiant section pipes to allow OTSG to operate at 90% steam quality • Centrifugal force moves all remaining water to the pipe surface • All water is now located on the pipe surface
Fully Developed Flow at 90% Steam Quality Using SQ90TM
Rifled pipe wall
Higher Concentration Impurities (Thicker Bottom Film)
Lower Concentrated Entrained Droplets (Non-Uniform Impurity Concentrations) Surface Water Film Layer
90% Steam Quality Benefits – Constant Fuel Input Operating Parameters
% Change
Quality
BFW Flow
BFW Temp
Fuel Heat Input
BlowDown Flow Rate
Dry Steam Flow Rate
BlowDown Flow
Dry Steam Flow
BFW Flow
Fuel Flow
%
m3/hr
Deg C
MW (LHV)
m3/hr
m3/hr
%
%
%
%
75
120.4
138
64.5
30.1
90.3
0
0
0
0
80
116.1
138
64.5
23.2
92.9
-22.8
+2.9
-3.6
0
90
108.4
138
64.5
10.8
97.6
-64.0
+8.1
-10.0
0
Typical 64.5 MW OTSG, 100bar(a) steam pressure
• Increased steam / production capacity • Reduced BFW requirement • Reduced blowdown volume
90% Steam Quality Benefits – Constant Dry Steam Flow Operating Parameters
% Change
Quality
BFW Flow
BFW Temp
Fuel Heat Input
BlowDown Flow Rate
Dry Steam Flow Rate
BlowDown Flow
Dry Steam Flow
BFW Flow
Fuel Flow
%
m3/hr
Deg C
MW (LHV)
m3/hr
m3/hr
%
%
%
%
75
120.4
138
64.5
30.1
90.3
0
0
0
0
80
112.9
138
62.6
22.6
90.3
-24.9
0
-6.2
-2.9
90
100.3
138
59.6
10.0
90.3
-66.8
0
-16.7
-7.6
Typical 64.5 MW OTSG, 100bar(a) steam pressure
• Reduced fuel consumption • Reduced BFW requirement • Reduced blowdown volume
Benefits of 90% Steam Quality
Constant Fuel Heat Input
Constant Dry Steam Flow
Pigging • OTSGs can be pigged using standard pigging procedures • Screw head attachments used as a rough cleaning of smooth piping which also cleans the rifle tips • Pin attachments are for cleaning smooth piping and rifle valleys • Number and alignment of pig pins match rifle profile • Pigging Frequency does not change when operating at 90% steam quality
Screw head pig for cleaning rifled tips
Pin pig for cleaning between rifles
Pigging • Pigs successfully pass through entire pass • Pig core markings indicate that the pig travelled through the pipe pattern • Inspections show no evidence of fouling or gouging of the tubes
Additional Points • 90% steam quality is achievable using the same BFW as a 75% - 80% OTSG
• Technology has been retrofitted in OTSGs (>220MMBtu/hr) operating at producing faculties in Alberta • OTSGs supplied by IST in Alberta / Saskatchewan operate at 90% steam quality • Devon Jackfish 2 pilot is currently taking place
Devon Pilot Objectives • Validate the process guarantee (90% steam quality)
• Validate reliable operation • Establish optimum operating limits
• Collect baseline data for commercialization • Validate potential to improve water usage • Reduction in blowdown up to 58% • Reduction in makeup water up to 15% • Reduction in water throughput up to 9.6%
Thank You
Albert Mansour Innovative Steam Technologies (IST) [email protected] 519-740-0036
Once Through Steam Generator (OTSG)
Boiler eedwater (BFW) Radiant Section
Convective Section Dry Steam
75% - 80% Wet Steam Quality (Typical)
Separator (SAGD)
Blowdown (Wet Steam Water Content)
Limits to Higher Steam Quality • Typical OTSG radiant section piping is smooth
• Radiant pipe operates under annular flow regime • Annular flow is a dispersion of water on the pipe surface with entrained droplets in the core steam flow
Annular flow regime
Limits to Higher Steam Quality • Traditional OTSG steam quality limits are between 75% and 80%
• BFW impurities concentrate in remaining water before exiting OTSG • At higher steam qualities, smooth pipes have low water quantity on the pipe surface • Operation above 80% may lead to scale deposit formation due to dry spots • Deposits can lead to pipe overheating and failure
Annular Flow at 80% Steam Quality
Pipe Wall
Higher Concentration Impurities (Thicker Bottom Film)
Lower Concentrated Entrained Droplets (Non-Uniform Impurity Concentrations) Surface Water Film Layer
Solutions to Achieving Higher Steam Quality – SQ90TM • Utilizing modified (rifled) piping in select radiant section pipes to allow OTSG to operate at 90% steam quality • Centrifugal force moves all remaining water to the pipe surface • All water is now located on the pipe surface
Fully Developed Flow at 90% Steam Quality Using SQ90TM
Rifled pipe wall
Higher Concentration Impurities (Thicker Bottom Film)
Lower Concentrated Entrained Droplets (Non-Uniform Impurity Concentrations) Surface Water Film Layer
90% Steam Quality Benefits – Constant Fuel Input Operating Parameters
% Change
Quality
BFW Flow
BFW Temp
Fuel Heat Input
BlowDown Flow Rate
Dry Steam Flow Rate
BlowDown Flow
Dry Steam Flow
BFW Flow
Fuel Flow
%
m3/hr
Deg C
MW (LHV)
m3/hr
m3/hr
%
%
%
%
75
120.4
138
64.5
30.1
90.3
0
0
0
0
80
116.1
138
64.5
23.2
92.9
-22.8
+2.9
-3.6
0
90
108.4
138
64.5
10.8
97.6
-64.0
+8.1
-10.0
0
Typical 64.5 MW OTSG, 100bar(a) steam pressure
• Increased steam / production capacity • Reduced BFW requirement • Reduced blowdown volume
90% Steam Quality Benefits – Constant Dry Steam Flow Operating Parameters
% Change
Quality
BFW Flow
BFW Temp
Fuel Heat Input
BlowDown Flow Rate
Dry Steam Flow Rate
BlowDown Flow
Dry Steam Flow
BFW Flow
Fuel Flow
%
m3/hr
Deg C
MW (LHV)
m3/hr
m3/hr
%
%
%
%
75
120.4
138
64.5
30.1
90.3
0
0
0
0
80
112.9
138
62.6
22.6
90.3
-24.9
0
-6.2
-2.9
90
100.3
138
59.6
10.0
90.3
-66.8
0
-16.7
-7.6
Typical 64.5 MW OTSG, 100bar(a) steam pressure
• Reduced fuel consumption • Reduced BFW requirement • Reduced blowdown volume
Benefits of 90% Steam Quality
Constant Fuel Heat Input
Constant Dry Steam Flow
Pigging • OTSGs can be pigged using standard pigging procedures • Screw head attachments used as a rough cleaning of smooth piping which also cleans the rifle tips • Pin attachments are for cleaning smooth piping and rifle valleys • Number and alignment of pig pins match rifle profile • Pigging Frequency does not change when operating at 90% steam quality
Screw head pig for cleaning rifled tips
Pin pig for cleaning between rifles
Pigging • Pigs successfully pass through entire pass • Pig core markings indicate that the pig travelled through the pipe pattern • Inspections show no evidence of fouling or gouging of the tubes
Additional Points • 90% steam quality is achievable using the same BFW as a 75% - 80% OTSG
• Technology has been retrofitted in OTSGs (>220MMBtu/hr) operating at producing faculties in Alberta • OTSGs supplied by IST in Alberta / Saskatchewan operate at 90% steam quality • Devon Jackfish 2 pilot is currently taking place
Devon Pilot Objectives • Validate the process guarantee (90% steam quality)
• Validate reliable operation • Establish optimum operating limits
• Collect baseline data for commercialization • Validate potential to improve water usage • Reduction in blowdown up to 58% • Reduction in makeup water up to 15% • Reduction in water throughput up to 9.6%
Thank You
Albert Mansour Innovative Steam Technologies (IST) [email protected] 519-740-0036
