Water sustains life and allows communities to thrive. But as the global demand for water increases and droughts become more frequent, water scarcity is a rising problem. This is felt, of course, in both drinking water and agricultural irrigation. But such scarcity also deeply affects the many industries — including the oil and gas industry — that rely on a secure water supply chain.
Water is essential to the production of oil and gas, used in drilling, fracking and refining. As the population increases, so does the need for water and energy. Generating and delivering that additional energy requires still more water. It’s clear: Competition for this vital resource will only continue to grow.
More Demand, Less Water
A United Nations report predicts a 55 percent increase in global water demand by 2050. And this comes after a 15-year period — 2014 through 2014 — when as much as 70 percent of the United States experienced conditions that were abnormally dry or worse, according to the Environmental Protection Agency. And with climate change, these challenges are only expected to increase.
The Columbia Water Center has identified California, the Southwest and Midwestern plains states as drought-prone zones. Refineries in these areas already face the twin challenges of increasing water supply costs and increasingly restrictive water regulations. And when you consider that a significant portion of the population growth over the next two decades is expected in California, Texas and the Southwest, that will place even more strain on water resources in these regions.
Many refineries nationwide are implementing incremental solutions to increase process efficiency and reduce water demand. Advances in water treatment technologies are also moving the needle. Understanding how one Midwest refinery is tackling the challenge of drastic water restrictions can help refineries in other areas as they anticipate and prepare for the challenges ahead.
The ‘Other’ Liquid in Refining
Water is essential in oil refineries, used for cooling and for steam in refining processes to improve process efficiency. Tightening regulations has already reduced water usage, supported by innovative technologies to enhance water minimization, use alternative water supplies and allow wastewater reuse.
The primary sources of reuse water are noncontaminated stormwater, stripped sour water, vacuum and crude tower overhead water, and wastewater (refinery and municipal sources). Primary reuse opportunities are the desalter, boiler feed water (BFW), and cooling tower makeup water (CTW). Reuse is not appropriate in all refineries, based on factors including the type of crude processed, interconnecting piping, reliability risk to refinery process units, and risk to the refinery wastewater treatment plant.
Reducing Environmental Impact at a Midwest Refinery
A refinery in the Midwest faced a significant challenge: Reduce the amount of water being drawn from the region’s aquifer and minimize environmental impact. The facility uses millions of gallons of water a day to serve multiple cooling water towers and a boiler system for steam production, both critical to the refining process. To achieve its goal, the refinery owner looked to Burns & McDonnell to develop an innovative solution for reusing waste streams and maximizing water recovery.
An initial feasibility study confirmed that the city’s wastewater could be purified to the standards necessary for the cooling towers. Though the refinery had relied on using a water treatment process with leased trailers for several years, the owner recognized the need for a permanent water treatment plant.
Reflecting a desire for environmental stewardship, the owner built an integrated membrane facility and the treatment of multiple water sources on the refinery’s site. The facility reuses municipal wastewater effluent and water from chloride remediation wells, providing finished water at two water qualities to serve both CTW and BFW needs. The result? The refinery reduced the draw from the aquifer by an estimated 1.5 million gallons of water per day.
The design and operation of this integrated membrane facility is an effective model for refineries that anticipate facing water scarcity in the future. The project demonstrates:
- Potential applications of wastewater reuse, from potable water treatment to industrial uses.
- A flexible treatment system that can handle the variation between multiple water sources with varying qualities.
- A facility that combines both nanofiltration (NF) and reverse osmosis (RO) membrane elements operating in parallel.
Are you interested in talking about solutions to the water scarcity issues that will likely plague your refinery in the near future? Feel free to connect with me on LinkedIn or comment below.
Larry Close, PE, is a process engineer specializing in water and wastewater treatment at Burns & McDonnell. His experience is in treatment feasibility studies, pilot studies and final design related to oil/water separation, metals removal and biological treatment.