# Refinery Turnaround Simulation

How a refinery unit is shut down, cleaned and checked during a planned turnaround, from scaffolding and blinds to drone and robot inspection of the tank walls\.

By 8Scale Ntegrity

Topic: Engineering

[Open the interactive Jig](https://ask.jig.com/j/1rDB0CoJpeeW)

## Transcript

### 1. A refinery takes a break

A refinery runs day and night, turning crude oil into fuels\. Every three to five years, each big unit stops for a turnaround: a planned pause for cleaning, checking and repairs\. Let's walk through one\.

The busy part usually lasts three to five weeks, but planning starts a year or more ahead\.

### 2. Scaffolding goes up

To reach every part of a tall tower, crews build scaffolding: a frame of steel tubes with wooden decks, one level about every two metres\. Much of it goes up while the plant is still running, so no time is lost later\.

On big jobs, scaffolding can take up to a fifth of all the hands\-on work\.

### 3. Shut down, cool and clean

The flame at the flare dies down and the furnace goes dark\. Oil is drained out, then steam and water wash the towers and tanks clean\. This shutdown takes a few days\.

During a turnaround the site gets busier, not quieter: the workforce can double or triple\.

### 4. Lock out every pipe

Before anyone opens equipment, workers fit blinds: solid metal plates clamped between pipe flanges, the rings that join two pipe sections\. A spectacle blind is shaped like an 8 and flips from the open ring to the solid plate, so nothing can flow in\.

Every blind is listed and tagged, so all of them are taken out again before restart\.

### 5. Open the manways

Manways are round, bolted doors on towers and tanks, just wide enough for a person\. Opening them lets fresh air in, and a blower pushes air through\. Then the air is tested: oxygen first, then flammable gas, then toxic gas\.

A manway opening is usually about half a metre across\.

### 6. Send in the drone

Instead of building scaffolding inside the tank, inspectors fly in a small drone wrapped in a round cage\. The cage lets it bump walls safely\. With no GPS indoors, it finds its way with lasers and cameras and builds a 3D map of the walls\.

In one case, two people inspected six tanks in a single day with a drone\.

### 7. Robots read the steel

A crawler robot climbs the tank wall on magnetic wheels\. Its ultrasonic probe sends sound pulses through the steel and times their echoes to measure how thick the wall still is\. Green marks are healthy; the amber mark shows thin steel\.

Robots and drones give a first look\. People still decide what to fix and do the repairs\.

### 8. Repair, close up, restart

Welders fix the thin spot\. Then the manways are bolted shut, every blind is flipped back, and the scaffolding comes down\. Utilities start first, then oil flows again and the flare relights: ready for years of work\.

Surprises found inside are the main reason turnarounds run longer than planned\.