Oilfield Produced Water Management: Which Technologies Will Gush to Success? (“WaterTech Online”)


Published on 10 December 2014

Source: watertechonline.com

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The global oil industry is emerging as a surprisingly fertile arena for the development of a growing number of innovative water treatment technologies. One US-based start-up has invented a new process that is capable of cleaning the very briny water that emerges from oil wells. How are other global technology providers stepping up to provide solutions for this industry?

By Andrew Williams

 

Estimates suggest that for every barrel of oil brought to the surface in North America, so are eight barrels of water. Although challenging to treat, produced water – highly saline and contaminated – has become a focus of companies to innovate and develop new treatment technologies.

 

One of these companies is Massachusetts-based Gradiant Corporation, formed as a spin-out company by Massachusetts Institute of Technology (MIT) alumni Anurag Bajpayee and Prakash Govindan. As co-founder and CEO Bajpayee explains, the company’s water treatment technology is based on its proprietary carrier gas extraction (CGE) technology, used in conjunction with a range of other “complementary technologies and innovations”.

 

“CGE was invented by [us] at MIT to handle the most challenging water treatment problems,” he adds. “It was commercialised by the company working closely with oil and gas industry partners. We are currently focused on treating produced and flowback water from oil and gas operations and converting every drop of the influent into re-usable water streams,” he adds.

 

According to Professor John H. Lienhard, director of the Center for Clean Water and Clean Energy at Massachusetts Institute of Technology (MIT), the technology works by causing water vapour to evaporate from a wastewater stream into a moving airstream and then “condensing the vapour out of the airstream in another location”.

 

“The system uses relatively advance thermodynamic principles to recovery energy effectively and lower the required energy consumption,” he says.

 

The technology has been commercialised by Gradiant Corporation and is currently treating water that is produced during unconventional gas extraction in West Texas.

 

“The results have been excellent,” adds the professor. “It can be applied to a very wide range of industrial wastewaters,” he adds.

 

In Lienhard’s view, the key advantage of the new technology is that, “unlike many other newly proposed technologies,” it is “very robust and does not depend upon the invention of new membranes, new liquids, or new materials”.

 

“It includes a highly innovative direct-contact condenser that minimizes hardware while maximizing thermal effectiveness,” he adds.

 

Avoiding Pitfalls
The main motivation for the creation of the new technology was the need to develop an effective means of treating the water that emerged as a by-product of oil drilling, which Bajpayee says contains “high levels” of oil, grease, suspended solids and volatile organic compounds and “very high levels of dissolved solids,” often two to six times that of seawater, that are “very difficult to overcome using existing technologies”.

 

He adds: “The presence of oil and grease creates operational issues with membrane based techniques and so do the harsh thermo-physical properties of high salinity water. The presence of volatile compounds which have similar distillation temperatures as water creates operational issues for conventional thermal desalination techniques. The high levels of contamination also makes the water extremely corrosive to metals and other usual materials of construction,” he adds.

 

For Bajpayee, Gradiant’s novel method of decontaminating water by using a carrier gas helps the CGE system to “steer clear of many of these pitfalls”. He also points out that operation at lower temperatures and ambient pressures makes it possible to “use simpler materials of construction and avoids the need for exotic metals” – meaning that the proprietary primary treatment system, used in combination with CGE, helps to “eliminate pitfalls caused by the presence of oil and grease and scaling ions.”

 

“Gradiants’ technologies are already deployed industrially and the company is successfully operating a 12,000 bpd (barrels per day) commercial plant in Midland, Texas for the treatment of oilfield produced water. Our customers are happy with the operation and the performance of the system, as well with our service teams’ competence, professionalism, and attention to safety detail,” adds Bajpayee.

 

The company is also currently in discussions relating to the deployment and operation of additional plants with several other customers. Bajpayee foresees most of the future growth in the company’s operations being in the North American oil and gas industry but is also in “active discussions” with international customers about potential future industrial wastewater applications.