TEXAS PLANT WILL USE NEW PROCESS TO COPRODUCE PROPYLENE OXIDE, MTBE

Aug. 30, 1993
Anne K. Rhodes Refining/Petrochemical Editor Texaco Chemical Co. is building a $400+ million facility to produce 1.2 billion lb/year (14,000 b/d) methyl tertiary butyl ether (MTBE) and 400 million lb/year (about 500 metric tons/day) propylene oxide (PO). The facility-under construction at Port Neches, Tex.-will utilize a newly developed Texaco process that coproduces the two chemicals (Fig. 1).
Anne K. Rhodes
Refining/Petrochemical Editor

Texaco Chemical Co. is building a $400+ million facility to produce 1.2 billion lb/year (14,000 b/d) methyl tertiary butyl ether (MTBE) and 400 million lb/year (about 500 metric tons/day) propylene oxide (PO).

The facility-under construction at Port Neches, Tex.-will utilize a newly developed Texaco process that coproduces the two chemicals (Fig. 1).

NEW TECHNOLOGY

In the late 1970s, Texaco Chemical disassembled a unit in Port Neches that had produced propylene oxide via the chlorohydrin process, says Michael Kern, manacles of Texaco Chemical's Jefferson County operations.

In the early 1980s, Texaco began investigating new propylene oxide technologies. By 1992, the company had developed about 80 related patents in its Austin, Tex., research facility.

A pilot plant was built at the Austin facility in the mid-1980s. This plant's design was based on the process developed in Austin, complemented by technology from a design team consisting of engineers from Port Neches and Texaco's Central Engineering Department in Houston.

The Port Neches facility is the first plant to be built using the technology that came out of that development. The process produces propylene oxide and tertiary butyl alcohol (TBA) from the reaction of isobutane with oxygen in one step, then in a second step with propylene. The TBA is then reacted with methanol in a one-step process that synthesizes MTBE (Fig. 2).

A purification system removes small amounts of normal butane, sulfur, and propane from the isobutane stream.

The technology involves a peroxidation reaction, which produces a peroxide (tertiary butyl hydroperoxide, or TBHP) and an alcohol (TBA). The peroxide is then sent to an epoxidation reaction, where it is reacted with propylene in the presence of a proprietary Texaco catalyst. The resultant TBA from both reactions is combined. The process produces, on a mass basis, MTBE and PO in a 3-to-1 ratio. It is neither a producer nor consumer of hydrogen, says Kern.

Potential customers have tested products from the Austin pilot plant. The PO product passes all quality tests, and the MTBE surpasses the quality of that which is currently available on the market.

Texaco Chemical has chosen to defer deciding whether to license the new process until after the Port Neches plant starts up. The company prefers to obtain commercial experience on a process before licensing it to outsiders.

The new plant will be operated using distributed and advanced control systems supplied by Foxboro Co. A storage area is being built to house propylene oxide, TBA intermediate, solvents, byproducts, and other chemicals.

PORT NECHES FACILITIES

Texaco Chemical has two existing plants in Port Neches. The east plant is adjacent to the construction site for the new MTBE/PO facility. A new office building is also under construction near the PO/MTBE site.

The east plant produces 300 million lb/year ethylene. Additional ethylene is brought in by pipeline from Port Arthur to produce ethylene oxide, ethanolamines, ethylene glycol, surfactants, morpholine, and other chemicals.

The East plant also recovers ethylene and propylene from a fluid catalytic cracker (FCC) stream from the nearby Star Enterprise refinery in Port Arthur.

Star Enterprise is a 50/50 joint venture, formed in 1988 by Texaco and Saudi Arabian Oil Co. The Port Arthur refinery has a crude capacity of 236,000 b/d.

Texaco's West Port Neches plant produces MTBE and butadiene from other FCC and ethylene plant streams. Texaco Chemical also has an additive and olefins facility in Port Arthur. This plant produces lubricant and fuel additives, ethylene, and propylene. The company also operates two large docks on the Neches River. Ships coming from the Gulf of Mexico reach the Texaco docks by traveling through Sabine Pass and the Intracoastal Canal.

CONSTRUCTION SCHEDULE

Construction of the PO/MTBE plant started in September of 1992. The heaviest equipment was shipped to the site by barge. The balance came via road and rail.

Engineering is more than 90% complete. The last tower was installed in July and mechanical completion is scheduled for July 1994 (Fig. 3).

Brown & Root Braun is the major contractor for the on site facility. It now employs about 1,800 workers and subcontractors, and this number is increasing.

Roughly 20 steam, water, and raw materials pipelines will be installed to connect the new site to existing facilities, says Ken R. Keith, manager of the PO/MTBE project. Modifications are also being made to one of Texaco Chemical's docks to facilitate loading PO onto ships and barges. MTBE will be loaded at another Neches River dock.

Texaco expects the PO/MTBE facility to produce 125 permanent positions. Staffing is currently under way. Extensive precommissioning training is planned for personnel.

FEEDSTOCKS

Propylene supplies for the new plant will come from Texaco Chemical's facilities in Port Neches and Port Arthur. Isobutane will be purchased via a contract with a supplier in Mont Belvieu, Tex.

Methanol from Texaco Chemical's unit at the Star Enterprise refinery in Delaware City, Del., will provide feedstock for the MTBE synthesis.

PRODUCT USES

Texaco Chemical says the new facility will enhance its existing product lines. And although petrochemical markets are not as favorable as they were when the project began, the company considers the plant a good long-term investment and expects MTBE markets to improve.

Texaco will use the MTBE internally to meet the reformulated-fuels requirements of the 1990 U.S. Clean Air Act Amendments. The new facility will not produce all the oxygenate needed by Texaco and Star Enterprise refineries, but it will go a long way toward satisfying that goal, says Kern.

This projection takes into account an assumption that ethanol will play a big role in the oxygenates market, as both gasohol and ethyl tertiary butyl ether.

AUXILIARIES

Texaco Chemical has taken advantage of state-of-the-art technologies to keep emissions to a minimum. Emissions rates for the plant are thus expected to be well below current standards, according to Kern.

A smokeless ground flare is being installed as well, with a special fence around it to reduce visibility and noise.

A separate raw-water treatment plant is being built for the new plant. The waste water, however, will go to an existing facility.

Existing utilities at the east plant will be supplemented with an adjacent new facility. Steam and water supply will be added, and power will come from a natural gas turbine-fired cogeneration plant that has been in operation at the east plant for about a year.

Copyright 1993 Oil & Gas Journal. All Rights Reserved.