We have documented how some wastes, by-products, of the coal-to-liquid conversion process, most especially Carbon Dioxide, can be efficiently, and even profitably, recovered from process streams and recycled into additional products of value.
Herein we document that yet another by-product, "phenol", of coal conversion, and other coal use technologies, can be effectively recovered and profitably utilized.
And, we will note that "phenols" generically, are common organic compounds. There is nothing particularly unique or threatening about them, but their generation by coal utilization processes has prompted environmentalist objections to the increased use of coal, especially when it is employed to make liquid fuels.
First, an excerpt from the phenol extraction patent linked above, and it's an important one:
"The waste water to be treated originates for instance from the gasification of coal, and in particular from the gasification of coal in a fixed bed, or from the hydrogenation or carbonization of coal."
So, the inventors, who seem to be German, as they are listed in the attached file, but who have no readily-discernible corporate or government affiliations, acknowledge the industrial gasification of coal, the initial step of liquefaction processes, and the "hydrogenation" of coal, which is the direct chemical process of liquefying it, and specify those processes as the prime reasons for developing a phenol extraction process.
And, note the following:
"It is the object underlying the invention to save energy when extracting phenols by means of a solvent mixture, and to flexibly effect the distillative separation of the phenols and the separation of the solvent mixture prior to its reuse."
They are, apparently, also looking at efficiencies in the process. The objective is to "save energy" and recycle, "reuse" the solvent.
Once we have efficiently recovered the phenol, it has quite a lot of commercial utility, as follows in a brief excerpt from our own, US, EPA's web site:
"Uses (of phenol):
- The primary use of phenol is in the production of phenolic resins, which are used in the plywood, construction, automotive, and appliance industries.
- Phenol is also used in the production of caprolactam and bisphenol A, which are intermediates in the manufacture of nylon and epoxy resins, respectively.
- Other uses of phenol include as a slimicide, as a disinfectant, and in medicinal products such as ear and nose drops, throat lozenges, and mouthwashes."
And, to further confirm that phenols, as might be found in the wastes of coal-to-liquid conversion plants, do have value, and can be efficiently recovered, and are worth recovering, here is yet another patent for that purpose:
"Title:
Extraction of phenol-containing effluent streams
United States Patent 6972345
Abstract:
A process for extracting phenol from a phenol-containing aqueous solution is disclosed."
We submit this second patent for phenol extraction toward the end of demonstrating the compound's value. This phenol extraction process was developed, and the patent is held, by Bayer. They make a lot of resins and plastics of the kind the EPA specifies; and, the construction, automotive and appliance industries are among the largest customers they serve. It might be valid to suppose they are recovering phenol from waste streams so that they can use it as a raw material for further resin and chemical manufacturing purposes.
Otherwise, there would be little value in developing, and patenting, a process centered on treating or recovering just one organic compound from a complex waste stream. Other methods exist for precipitating or removing entire, undifferentiated groups of chemicals. These enclosed patents are methods for "mining" a valuable substance from effluents.
As we've said previously, our use of coal, whether for the generation of power or conversion into liquid fuels, doesn't generate wastes or pollutants, but by-products which can be profitably harvested and used.