In what it termed an ``astounding'' discovery, Exxon Chemical Co. announced Feb. 27 it has developed a new process that could increase the output of gas-phase polyethylene reactors by 151/2 times. Exxon is calling its patented development supercondensing technology.
The technology appears to be similar in concept - while being significantly different in fact - to condensing-mode technology developed and patented by Union Carbide Corp. of Danbury, Conn., and it takes condensing-mode technology a large step forward.
Also, the process is separate from the condensing-mode technology development announced by British Petroleum several weeks ago. Carbide said it thinks the BP process infringes on its patents, and has threatened to take BP to court.
The Exxon process is applicable to PE and polypropylene production, but Exxon said it has not investigated PP production as thoroughly as PE production.
If the claims Exxon has made about its supercondensing technology are true, John Hubby, general manager of Houston-based Phillips Sumika Polypropylene Co., said PE producers may not have to build new PE production capacity for 10-15 years because they can extend the production capacities of existing plants.
Hubby, a chemical engineer, said Exxon's development apparently is a significant incremental step for polyolefin production.
Exxon of Houston announced its development at the Polyolefins IX conference in Houston Feb. 27, and said it has started to implement the new technology in some of its existing plants.
Besides increasing the output of existing PE reactors, Doug Selman, Exxon vicepresident for polymers technology, said the technology could reduce the cost of new PE production facilities 50 percent.
Exxon cannot realize the full extent of benefits from the process, according to Kenneth Sinclair, an industry consultant with SRI International of Menlo Park, Calif., because its PE reactors are too large. Sinclair talked about the Exxon technology in a speech delivered at the Polyolefins IX conference.
Exxon experimented with the process on a reactor designed to produce 38,000 pounds of PE an hour, Sinclair said. With the supercondensing process, the reactor was pushed to production rates of 100,000 pounds an hour, and easily could have produced 180,000 pounds, he said.
However, production limits were reached at 100,000 pounds because extruding and pelletizing equipment downstream from the reactor could not process any more PE powder than that, Sinclair said.
The new technology will add substantial life and production capacity to existing gas-phase reactors, he said.
By the year 2000, maximum output for existing gas-phase PE reactors ``will be around 151/2 times the original design,'' Sinclair said.
``In other words, a PE reactor built in the late 1960s with a design capacity of 40,000 tons per year will, by the end of this decade, be capable of producing up to 620,000 tons per year, given adequate downstream materials handling capabilities,'' he said.
Exxon said in a prepared statement that it plans to debottleneck its downstream processes during the next few years to reap the benefits of the supercondensing process.
In PP production, Sinclair said the supercondensing technology could be combined with high-temperature catalysts to increase the production capacity of existing reactors.
``We could see a gas-phase PP unit currently designed for 150,000 tons per year being capable of making 700,000 or even 1 million tons per year,'' Sinclair said.
Separately, a PE industry executive noted that the Exxon development and the BP condensing technology could represent threats to Union Carbide's dominance of licensing technology for the production of PE and PP resins.
Union Carbide gained dominance in licensing polyolefin technology with its development of gas-phase reactor processes in the late 1970s.
Since then, it has built on that development and guarded its position closely.
Sinclair noted that other technological developments, including supercritical slurry pro-cesses, the high-temperature catalysts used for PP production and new generations of metallocene catalysts for PE, are expected to increase production capacities and resin performances in the near future.
