Abstract
There has been a shift away from the use of warm lime softening (WLS) and
weak acid cation (WAC) ion exchange for produced water treatment to the use of
mechanical vapour compression (MVC) evaporation followed by high pressure
drum-type boilers. Approximately 18 steam assisted gravity drainage (SAGD)
produced water evaporators are operating or are in various stages of
construction in Alberta and overseas. Since the commissioning of the first such
evaporators in 2002, many technical advancements have occurred which have
resulted in reduced operating costs, improved reliability, reduced scaling and
fouling potential, improved distillate quality and improved boiler feed quality
for steam generation.
This paper provides details of the technical advancements in evaporative
produced water treatment based on full-scale operating data and lessons
learned. It also presents improved evaporator configurations, discusses
improvements in contaminant reduction and scale prevention systems,
demonstrates how capital and operating costs can be drastically reduced as
compared to earlier evaporator system designs, and provides recent advancements
in modularization, evaporator disposal treatment, deoiling, membrane
preconcentration, and zero discharge solids drying techniques.
Introduction
Over the past few years, there has been a rapid shift away from the use of
traditional produced water treatment methods using WLS for silica reduction and
WAC ion exchange for hardness removal, to the use of evaporative produced water
treatment methods at SAGD facilities. With the use of evaporative produced
water treatment, standard drum boilers are utilized for steam generation in
lieu of once through steam generators (OTSG) and vapour liquid separators. This
shift has occurred because of technical, economic and reliability factors,
resulting in markedly improved life cycle costs for SAGD facilities. A
simplified block flow diagram of the traditional approach to produced water
treatment and steam generation is provided in Figure 1. A block flow diagram
for the evaporative approach is provided in Figure 2.
© 2009. Society of Petroleum Engineers
View full textPDF
(
395 KB
)
History
- Original manuscript received:
24 June 2008
- Meeting paper published:
17 June 2008
- Revised manuscript received:
24 August 2009
- Manuscript approved:
21 September 2009
View Cart
