SYNGAS UNIT PROCESS DESCRIPTION

The unit supports a fixed bed and a spouted bed type reactor. The fixed bed reactor is used for catalytic activity measurements. The spouted bed is a promising reactor configuration in oxidative partial oxidation process, as it combines short residence times for the gas phase along with almost perfect mixing of the catalytic particles, which enhances the heat transfer inside the bed. The concept of the spouted beds is that gas enters from a small nozzle at the base of the catalytic bed at high velocity, creating a central dilute phase core.

SYNGAS Unit

The particles that rise inside the core rain back onto the bed in the form of a fountain, and they slowly travel downward inside the annular dense phase. The gas flows mainly inside the core, while a small percentage of flow is distributed to the annulus. The system is characterized by cyclic pattern of solids movement and high gas velocity. The two reactors share the same utilities and feed systems. A simplified process flowchart is given in Figure 1.

Simplified flow diagram of the spouted bed reactor pilot plant

The feed section consists of 8 independent gas feed lines and one liquid feed line with all the necessary safety and automation equipment, supplying the following substances: Methane (or natural gas), Nitrogen (or Helium), Carbon Dioxide, Hydrogen, Oxygen and Nitrogen. The feed lines of the first four substances are mixed together prior to feeding into the reactor. The pressure of this "reducing" gaseous mixture can be elevated (in case of using natural gas), by means of a gas compressor. The two other feed lines (Oxygen and Nitrogen mixture), consisting the "oxidizing" feed, are mixed separately and fed to the reactor by a separate route. Mass flow controllers control the above feeds. Two more Nitrogen feed lines are included: a Nitrogen line for purging the system controlled by a rotameter, and another line of Nitrogen for blanketing the spout reactor shell which is measured by mass flow indicator. Liquid water is delivered at the system pressure from a liquid feed vessel by a precise syringe pump. Water is converted into steam, after passing through a steaming unit before entering into the process. The mass flow controllers, the water pump and the air-operated valves are connected to the computer, allowing remote operation of the feed system.

Table 1: Specifications of spouted bed reactor

Residence time
<0.5 sec
Internal Diameter
54 mm
Maximum Reactor Temperature
1100 °C
Maximum Reactor Pressure
25 barg
Maximum Gas Flow
45 Slpm
Quench Steam Feed Rate
3-5 gr/min
Solids Catalyst Load
70-200 gr