CHETRA mechanical seals for refineries & petrochemicals

In refineries and in the petrochemical industry, crude oil is processed into various end products. Accordingly, different media in different states of aggregation must be sealed: Temperature ranges from -150°C to +400°C are characteristic for processing.

The partly explosive and environmentally harmful media are subject to regulations such as TA-Luft, ATEX, API or TÜV.

CHETRA seals meet these requirements and at the same time take into account the demand for economic efficiency through high MTBF/MTBR factors.

Extreme operating conditions and highest requirements

Innovative, often tailor-made solutions based on decades of experience in the industry with sound application technology advice.

Models

References

Quality, Innovation and customized solutions.

Environmentally friendly and centrally monitored

In order to comply with the significantly reduced emission values of the TA-Luft 2002 (5.2.6.1), approximately one quarter of all pumps in operation in Bavaria’s largest refinery were equipped with modern multiple mechanical seals and corresponding accessories. The refinery’s own specifications, API 682 and ATEX 95 as well as the operator’s wish for standardisation were taken into account.

In close cooperation between the refinery, the industrial service provider for the conversions and the CHETRA technicians, a pre-assembled CHETRA double mechanical seal with respective cover and sleeve adaptation to the pumps was selected – so no modification of the units was necessary.

For optimum supply, each mechanical seal was equipped with a loop system. These are fed by a central replenishment unit with a volume of 600 l. By means of an integrated pressure transmitter a permanent monitoring with signalling to the control room is carried out.

Modern Combi-Cracker - reliable mechanical seal

In the construction of the modern combi-cracker in a large German refinery, the focus was on high economic efficiency through rapid conversion to diesel or gasoline production as dictated by the market. These requirements apply equally to the mechanical seals and accessories used for the pumps.

90 % of all mechanical seal applications were equipped with CHETRA double mechanical seals in compliance with API 682 and refinery standards. The requirements also demanded ATEX 95 and TA-Luft 2002 conformity as well as extensive standardization.

Application data: up to t = 380°C and p = 60 bar

Sealing medium: TA-Luft compatible thermal oil.

3 mechanical seal types cover these requirements:

Type 875 A, Type 807 AS/ HD and Type 857

Loop systems with bubble accumulators (either with heat exchangers or finned tube coolers and central replenishment units) were also used.

No failure in the heart of an ethylene installation

One of the most important aggregates of an ethylene plant is the main quench oil pump. The central requirement on the mechanical seal is reliability and service life (MTBF factor).

In a comparative study of all European ethylene plants conducted by the operator, the CHETRA mechanical seal used achieves the highest MTBF factor.

At no time in the investigated applications was it necessary to shut down or repair the pump(s) due to a mechanical seal failure.

The operating data for this application:

Dw: 110 mm
p: 18 bar
t: 175° C
n: 1500 min-1
Service life achieved > 4.5 years

Products

The listed mechanical seals are without exception cartridge seals, available according to API 682 and customer-specific standards and adapted to the respective unit.

Further mechanical seal versions are available.