Portable Water Purification System for Produced Water Using Wellsite Gas

Abstract:

Oil field produced water handling has been industry challenges because of the sustainability problems including economic, environmental, and societal issues associated with current water management methods. Meanwhile, the world is running out of natural fresh-water resources and most available technologies deployed to purify water to freshwater standards are expensive to build and operate. Reverse osmosis desalination and traditional thermal distillation require expensive equipment and substantial amounts of energy. There is a need to sustainably reduce equipment costs and operating costs including energy consumption when purifying produced water for freshwater reuse.

This paper presents an advanced water purification technology, developed by Katz Water Technology, and funded by National Science Foundation (NSF). The technology utilizes a novel system based on thermal distillation mechanism, which can achieve high standard clean water and significantly reduce the equipment and operation costs. This patented technology performs the entire thermal distillation process including distillation and separation inside a heat exchanger to significantly increase energy efficiency. Existing heat sources or waste energy such as, flare gas can be utilized to operate the modified heat exchangers.

A portable prototype with a maximum throughput of 50 barrels per day was tested on multiple samples including produced water. This standalone piece of equipment was able to remove over 98 percent of the contaminates in a single pass through of less than 10 seconds. A high TDS sample was tested from Oman and reduced the TDS from over 150,000 TDS to less than 3,000 TDS making the treated produced water suitable for freshwater agricultural reuse. This will create a new resource recovery and circular water economy at the wellsite.

Oil field produced natural gas, worth billions of dollars, has been wasted by being flared annually. This flared gas can be utilized to purify water using thermal distillation, vapor extraction, and condensation. This unique onsite approach solves three pressing problems faced by the oil and gas industry. These problems include gas flaring, produced water disposal and sourcing water for oilfield operations such as, hydraulic fracturing, drilling and water flooding.