Safety, Protection against Corrosion and Cabinet Pressurisation in Refineries
The environment in a refinery is highly corrosive. This makes it necessary to deploy control systems not only to protect staff but also to protect the equipment controlling the processes, in order to ensure their reliability.
Bioconservacion has equipment that is specially designed for the safety of staff, and for protecting against corrosion in control rooms and cabinet pressurisation equipment. Some of the CEPSA refineries in Spain have this equipment installed.
In particular, the CEPSA Gibraltar San Roque refinery in Cádiz was provided with a system with packed bedding for the safety of staff - the Packed Bed System (PBS). The packed bed system includes the following filters:
- G4 particle filter - a pre-filter that collects dust and traps the larger particles, protecting meshes and granules
- Vertical beds - the air passes through the holes in the perforated plate and goes through the Bi-On filtering media that are placed there in accordance with the contaminants to be treated. Filling these vertical beds is a relatively simple operation, which does not require tools or highly qualified specialists.
- Final F7-type particle filter - an extremely efficient filter for eliminating particles.
The equipment has to protect a room of 155 cubic meters where between seven and nine people would be accommodated for between 20 and 30 minutes if necessary.
This time should be achieved in two distinct contamination scenarios.
- Scenario 1: 10280.00 mg/m3 H2S 80% + assorted hydrocarbons 20%.
- Scenario 2: 10900.00 mg/m3 HF.
The CEPSA Tenerife Refinery has a Positive Pressurisation Unit installed in which some of the external air is gathered and cleaned, and pressurises a 60 square metre control room. In addition, some of the air is used for recirculating and cleaning the air of possible contaminants from within and from door openings.
This equipment is designed to provide positive pressurisation using air that is free from corrosive gases in environments containing computers, control rooms, engine control centres and electronic and electrical equipment.
There are two types of configuration: horizontal and vertical. However, the equipment is made to order according to the customer's particular requirements and desired specification.
There are different filtering media to eliminate the differing types of gases. The commonest gases are hydrogen sulphide, sulphur dioxide, nitrous oxides, and chlorine and ammonium compounds.
In the refinery there is a set of 220 v to 110 v transformers.
The electrical cabinet pressurisation equipment installed must fulfil two requirements: it must provide enough ventilation to prevent the equipment from overheating, and it must clean the air coming into the cabinet.
Bioconservacion has a fully-equipped laboratory for ensuring good corrosion monitoring. Through the analysis of test coupons, corrosive agents are characterised and the aggressiveness of the environment is classified in accordance with the ISA 71.04 standard.
The laboratory is also able to measure the remaining life of filtering media. It offers its customers this service so they can ensure that filters are changed at the right time.