Also known as: platformer, hydroskimmer, CRU, CCR, SCR, powerformer, ultraformer, magnaformer, rhenifomer
The purpose of the reformer is to upgrade heavy naphtha into a high-value gasoline blend stock by raising its octane. The primary product of the reformer is reformate. However, it also generates large amounts of hydrogen that can be used in the hydrotreaters and hydrocrackers. Reformers are sometimes called hydroskimmers because of the hydrogen they produce (skim off).
The reformer is a critical unit for making high-quality gasoline and avoiding production of low-octane heavy naphtha. Also, as sulfur specifications have tightened, forcing greater use of hydrotreating, the value of the hydrogen produced by the reformer has increased.
Reformers are split into two main types of technologies:
- SR reformer - Older units mostly have fixed beds of catalyst that need to be regenerated every few months by burning off the coke that forms on the catalyst during normal operation. These semi-regen (SR) reformers typically operate at relatively high reactor circuit pressures to minimize the amount of coke formation and to extend the periods between regeneration shutdowns as long as possible, but as a result they only achieve octane numbers of 95-98 in the reformate product
- CCR - Newer reformers are built with continuous catalyst regeneration (CCR) capability, so they can operate at lower reactor circuit pressures with higher coke make, as the coked up catalyst is moved continuously to a regenerator section where the coke is burned off the catalyst before it is returned to the reactor section. CCR reformers can often operate for three or more years continuously between turnarounds and can produce reformate product with octane numbers of 101-103
How it works
The first step is to hydrotreat the heavy naphtha feed to remove impurities such as sulfur and nitrogen that would be harmful for the reformer's platinum catalysts. This is done in a naphtha hydrotreater that may be considered part of the reformer, or a separate process unit.
Next, the feed is sent through a series of 3-4 reactor vessels. Each reactor vessel contains a platinum and alumina catalyst to drive the reaction. Also, for each reactor there is a furnace to inject additional heat as the reaction is endothermic.
The input to the reformer is a hydrotreated, high N+A naphtha. This can come from several sources:
- Straight run heavy naphtha - Produced in the atmospheric distillation of crude and sent through a naphtha hydrotreater
- Hydrotreated cracked naphtha - From the coker or visbreaker, and sent through the naphtha hydrotreater
- Heavy hydrocrackate - A heavy naphtha stream produced by the hydrocracker
The major products from the reformer are:
- Reformate - This is an aromatics-rich naphtha range material that is either blended into gasoline or separated into component aromatic streams that are sold as petrochemicals feedstocks
- Hydrogen - This is purified and used as feed to hydrotreaters or hydrocrackers
- Reformer gas - This mixture of refinery gas and light liquids is sent to the gas plant for separation
Most new units employ either the UOP or Axens CCR technology. However, there are a large number of existing older units employing other technologies.
- UOP - Platforming CCR technology
- Axens/IFP - Octanizing CCR technology
- ExxonMobil - Powerforming cyclic reforming technology
- BP/Amoco - Ultraforming semi-regen technology
- Chevron - Rheniforming semi-regen technology