Kerstin Hirsch, SEP Salt & Evaporation Plants Ltd.
The production of unconventional gas has undergone a fast and impressive development in recent years. Especially in the Marcellus Shale and Utica Shale formations in the north east of the USA, where new sources have been opened up and changed the gas market significantly.
The technology of hydraulic fracturing (fracking), which is utilized for the production of shale gas results in environmental side effects, which are causing a lot of attention not only in the USA, but also worldwide. In particular, the waste water that is generated, which is pumped into the drilling hole and comes partially back to the surface as back flow or produced water. This back flow increases the challenges to the operators of drilling sites and the cost of disposal influences the economic evaluation of such projects.
Although produced water can be disposed of by well injection, this results in high transportation and disposal costs, so that the treatment of produced water has now become a standard procedure.
Recently, an important step was achieved in the field of the waste water treatment by not only minimizing the volume by evaporation but also recovering a valuable product from the waste water.
In Pennsylvania, USA, a crystallization plant has been successfully put into operation which takes the produced water after chemical pre-treatment and not only concentrates it. but also selectively crystallizes the dissolved salt. The recovery of clean condensate fulfils the specifications for municipal water discharge and the production of salt for de-icing and other applications are the outgoing products, while the volume of purge for disposal is reduced to a fraction of the material feed.
While the first plant has proven the economic and environmental feasibility of thermal waste water treatment in the field of shale gas applications, SEP has now developed further steps to recover more valuable products from the remaining mother liquor.
|Create Date||July 6, 2018|