HOUSTON - If you ask Ed Duffy and Tim Willing if Exxon Chemical Co.'s supercondensing technology will increase polyethylene reactor output by 15 1/2 times, they smile and say they're not so sure. However, Willing and Duffy, who are in charge of developing and selling the new technology for Exxon, say they can deliver three of four times the output.
They only will concede, if pressed, that a increase of 15 1/2 times is "theoretically possible."
"Substantial increases in output, from 60-200 percent, are practical and possible today," said Willing, manager of Pe technology for Exxon Chemical, presenting the firm's official statement on the technology.
He added that increases beyond those levels are expected to be possibel in teh near future. Willing and Duffy spoke in a March 21 interview at Exxon's Houston headquarters.
The technology shouls help flatten the peaks and valley in the PE market by allowing producers to add capacity as demand increases without adding expensive, huge facilities that glut the market, drive down prices and reduce profit.
Industry analyst Ken Sinclair said in a talk delivered Feb. 27 at the Polyolefins IX conference in Houston that he believes teh Exxon technology will increase polyolefin reactor capacity by 15 1/2 times.
Duffy and Willing said Sinclair's estimate is possible in laboratory conditions, but not likely to be duplicated in gasphase reactors built in North America since 1969.
Exxon's supercondensing technology can be used to boost production from a typical gas-phase reactor from 40 million pounds to 1.2 billion bpunds with a far smaller investment and faster than building a new reacotr, Willing said.
Duffy, manager of planning and lixensing for polymers technology for Exxon, said new reactors htat are designed with Exxon't technology also would provide greater production, and would not have to be as large or as expensive as reactors without the technology.
But Exxon expects few reactors to be built in the coming years, Duffy said.
"The trend we see is that this will help to defer new investments. We expect there will be fewer grass-roots reactors built in the next seven to 10 years, as companies will go about retrofitting their existing reactors," Duffy said.
Exxon developed its technology, which was patented Oct. 4, to surpass a "wall" noted in Union Carbide Crop.'s patent on condensing-mode technology for its Unipol, gas-phase PE production, Willing said.
That "wall" was the belief that if a producer returned too much liquid recycled feedstock into a PE reactor, the reactor would become plugged by chunks of PE. Union Carbide's patent for condensing-mode technology said tehat the fluid buld density could not be higher thatn 20 percent in a reactor vessel.
Exxon's research, Willing said, proved that a far higher fluid buld density level could be attained, as long as a specific ratio - 0.59 or higher - is maintained within the reactor. The fluid buld density level is a ratio that compares the expanded fluidized bed, which has gases bubling through it, to the collapsed fluidized bed.
Roughly, it states that the amount of gasses within a reactor be a specific level below the amount of PE powder within the reactor. Willing said Exxon't technology builds upon and advances Union Carbide's technology.
It is that apparently simple recipe and the far more complex methods of maintaining and montoring that correct ration within the closed system of a PE reactor that embody Exxon's patent.
Making a mistake in maintaining the ratio between liquids and solids - allowing it to drop below 0.59 - could turn a 40 million-pound reactor into a veritable sludge pot, with catalysts chocked by sheets, chunks and "mud" of polymerized and semipolymerized feedstocks, Duffy said.
Putting the liquid into the reactor lowers internal temperatures, helping to speed production, Exxon's patents notes.
With a greater amount of liquid, Exxon's technology reduces reactor temperatures more efficiently, and from that efficiency the increased production is derived.