Quantum Chemical Corp.'s ill-fated Morris, Ill., petrochemical plant is expected to restart today, nine months after an explosion and fire shut it down.

Ethylene derivatives production at the site will restart in seven to 10 days. The complex, including Quantum's largest ethylene cracker, has been out of action since last June when an explosion damaged a propylene fractionator.The Morris facility was preparing to restart last September, when it was hit by another explosion in the plant's acetylene converter.

Today's scheduled start-up follows extensive repairs to the entire plant, as recommended by engineering company CF Braun, which was hired after the second accident to conduct a comprehensive "process hazard review" on the unit.

The decision to conduct the review lengthened Quantum's downtime after the second accident by two months. If the initial start-up goes smoothly, Quantum's ethylene derivatives capacity at Morris will be brought back on- stream soon afterwards.

Quantum officials declined to discuss last year's accidents and would not reveal the total cost of the damage. Most of that cost has been covered by insurance.

The plant's total derivatives capacity is about 540 million pounds a year of high-pressure, low-density polyethylene, and about 250 million pounds a year of linear low-density polyethylene. The plant also produces 300 million pounds a year of ethylene glycol.

Only one of the four high-pressure LDPE lines has been running in recent months, on ethylene supplied by other Quantum plants.

Quantum also is planning to activate a new 300 million pounds a year Unipol-process LLDPE unit in Morris in early April.

Once all these units are back on-stream, the company's total polyethylene capacity will be back up to about 850 million pounds a year of LLDPE, 1.79 billion pounds a year of LDPE and 1.65 billion pounds a year of HDPE, restoring Quantum's status as the largest polyethylene producer in the United States.