The impact of the shutdown of the catalytic unit on the entire plant
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A couple of days ago, our company’s catalytic unit stopped operating due to an interlock shutdown caused by a closed slide valve. Since the steam generated by this catalytic unit accounts for over 50% of the total steam produced in the plant, its shutdown led to significant fluctuations in the plant’s steam distribution network, affecting half of the plants’ equipment. Have you encountered similar situations? How was it handled?
Is there any backup steam? If there isn’t enough steam, operations have to be halted
We have encountered this problem as well; there was no other choice but to install a new boiler.
Catalysis is a major source of steam at 1.0 and 3.5 MPa, as well as the primary unit for processing fractionated oils and atmospheric residue; an emergency shutdown of the catalysis unit can lead to adverse effects such as fluctuations in steam production throughout the plant, fluctuations in fuel gas levels, and excessive wax oil inventory. Generally, it is necessary to activate the boiler to produce steam or purchase steam, reduce the volume in vacuum distillation and atmospheric distillation, and increase the output from coking, in order to maintain processing balance across the entire plant.
Most catalytic units generate a large amount of steam, so downtime inevitably has an impact on the entire plant. In the event of an accident, it is necessary to restore operations as quickly as possible, and backup boilers should be used to supply steam to the pipeline network. Third, other devices are handled in accordance with the relevant accident response plans.
Typically, a plant should be equipped with two boilers, and the steam generation capacity of these boilers should be determined based on the total steam demand of the entire plant. As one of the key steam-generating units in an oil refinery, the shutdown of the catalytic unit inevitably affects the steam supply for the whole plant. The catalytic unit generates steam at two pressure levels: 1.0 MP and 3.5 MP. Most of the steam at 3.5 MP is used internally, while 80% of the steam at 1.0 MP is supplied to other parts of the plant. Therefore, the shutdown of the catalytic unit has the greatest impact on the steam pressure at 1.0 MP in the system. When problems occur with the catalytic unit, it is necessary to activate the temperature and pressure reduction devices for the 3.5 MP steam produced by the power station, or the extraction systems for 1.0 MP steam from the turbines in the generator sets, in order to compensate for the insufficient steam pressure in the system.
Our company’s power plant also has backup boilers, but it takes some time to start them up and get them operating properly, so this still has an impact on the production throughout the factory.
Our steam boilers are too small, and they are coal-fired; as a result, the heating process is slow. Once there are abnormalities in the catalytic system, the only option is to sacrifice the gas processing units and the vacuum distillation units in order to protect the catalytic system at all costs
It can be purchased externally; if not available, then production has to stop
Generally, there are own power plants and power rooms available. Under normal conditions, the steam system generates a large amount of steam; in case of an emergency, the system supplies steam to maintain production, thus ensuring a high level of safety. If the external system fails to provide steam, it would be too late to start boilers only in the event of an accident.
A power plant should be built to generate electricity on regular occasions; when steam is in short supply, it can be used to supply steam instead
A catalytic shutdown has a significant impact on the entire plant. The raw material feeding areas certainly can’t handle it, and there’s no steam available for the units either; both upstream and downstream units are affected. Usually, when there’s a shutdown, it means the whole refinery comes to a halt for maintenance