Silicate Scale Control in Geothermal Brines.

摘要

The scaling characteristics of synthetic and East Mesa Well 6-1geothermal brines were studied using a specially constructed test unit. The test unit was capable of simulating a variety of process conditions including flashing of the brine and separation of the vapors from the liquid prior to the scaling test section. Heated,cooled and zero heat flux probes were used. A summary of silica chemistry as related to deposition from geothermal brines is given. A mathematical model was derived and used to correlate the data for the synthetic brines experiments. The scaling rate determined from this analysis was used to show the effect of Reynolds number,bicarbonate concentration,and addition of silica sand on scaling. Experiments at the East Mesa Test Site using brine from Well 6-1showed that the predominant scale was calcite. A mixture of iron and silica scale was the next most significant scale. No scale formed until the brine was allowed to flash. The location of scaling could be controlled by the separator operation. Relative to flashing,scaling was independent of heat flux.