Ruichang supplies horizontal catalytic reactors for Claus sulfur recovery units. The vessel holds the catalyst bed where hydrogen sulfide reacts with sulfur dioxide to form further elemental sulfur after the thermal stage. Gas distribution, catalyst support and the connections to the reheater and condenser determine how the reactor fits into the process train.
Where the catalytic reactor fits in a Claus unit
Process gas leaving a sulfur condenser is reheated before entering the catalyst bed. The Claus reaction converts remaining H2S and SO2 to sulfur and water. A downstream sulfur condenser then cools the gas and separates the sulfur. Further catalytic stages can repeat this sequence.
Conventional Claus reactors operate above the sulfur dew point to limit sulfur condensation on the catalyst. The inlet temperature depends on the stage duty and catalyst selection. The in-line heater, where used, and the reactor must be specified together.
A Claus catalytic reactor and a tail gas hydrogenation reactor have different duties. Hydrogenation in a tail gas treatment unit converts sulfur species back to H2S for downstream removal and recycle. Identify the required service before specifying a replacement vessel or catalyst.
Reactor construction and catalyst bed support
Ruichang’s handbook describes a horizontal carbon steel vessel with an inlet gas distributor, catalyst support structure, retaining screens, ceramic support media and bed temperature measurement. The distributor spreads the gas across the bed; the support assembly holds the catalyst in place.
- Inlet distribution: directs incoming gas across the bed and limits direct impingement on the catalyst.
- Support and retention: beams, grating, stainless steel screens and support media carry the bed and prevent catalyst migration into downstream equipment. Screen fit and sealing need attention during design and installation.
- Thermal protection: refractory and external insulation are selected for the specified temperatures and corrosion conditions.
- Temperature measurement: readings at several bed locations help identify uneven temperature profiles. The number and positions of the instruments follow the reactor and monitoring design.
- Outlet connection: vessel elevation and outlet geometry must suit the downstream condenser, piping and maintenance access.
Reference dimensions and project-specific parameters
The handbook gives a catalyst bed height of 0.9-1.2 m for the horizontal arrangement it describes. Confirm the bed dimensions against the selected catalyst and process duty.
| Parameter | Basis needed for the project |
|---|---|
| Catalyst volume and bed height | Gas flow, catalyst selection, conversion duty and the catalyst supplier’s sizing basis. |
| Gas hourly space velocity | State the gas-volume reference conditions and catalyst volume used in the calculation. |
| Pressure drop | Allow for the catalyst, support layers, distributor and the rest of the SRU pressure balance. |
| Design temperature, pressure and lining | Approved process cases, material specification, corrosion allowance and vessel design code. |
| Bed supports and instrumentation | Catalyst size and load, retention details, temperature monitoring and maintenance requirements. |
Catalyst choice follows the stage duty
Activated alumina and titanium dioxide are used in Claus service. Titania can support the hydrolysis of carbonyl sulfide (COS) and carbon disulfide (CS2). Oxygen-scavenging catalyst layers may also be specified where the process calls for them.
Bed layering, catalyst volume and temperature limits should be agreed with the process designer and catalyst supplier. Specify any protective layer for the feed conditions and catalyst selected for that stage.
Inerting, protective systems and shutdown provisions form part of the project design. Use the approved plant procedures and catalyst supplier instructions for operation and maintenance.
New reactor or replacement enquiry
State the reactor stage, gas composition, flow range, operating and design conditions, allowable pressure drop and catalyst specification. For a replacement, include the existing datasheet, general arrangement, nozzle schedule, support details and available lifting and catalyst-handling access.
For a replacement prompted by catalyst loss, damaged internals or abnormal bed temperatures, send the inspection findings. Include the observed symptoms and operating history so that the replacement scope addresses the underlying problem.
Discuss a catalytic reactor requirement or review the wider SRU equipment scope. For the process sequence, see the Claus process guide.
