HMDS Process
Seat : 3 chemin de Beaulieu, 86800 Sèvres-Anxaumont
Production site : 489 allée des Erables, 86130 Dissay
N°TVA : 91800543613

Equipment, Solutions and more

Reactor internals

HMDS Process provides equipment and solutions for catalytic reactors for new projects, replacement or revamping. The strength of HMDS process is a team with over 30 years’ experience in the oil & gas sectors which have acquired unique expertise in working on catalytic reactors and distillation columns equipment of major process licensors such as UOP, IFP, Shell, H.TOPSOE, EXXONMOBIL, Lurgi, UHDE etc. during their careers. It is an experience enriched by the diversification of products realized.

HMDS Process specializes in the design of catalytic reactor internals, distillation, absorption column internals and solid - liquid - gas separators. Our mechanical and hydraulic calculations of internals are thoroughly optimized by an experienced team for maximum efficiency.

Trust us, you will be satisfied.

Vessel Internals

HMDS process propose a wide range of internals for media retention which are used in different process because their very high mechanical resistance, important open area, precision and design flexibility make it a high performance equipment that fits all applications in high or low temperature

HMDS Process Internals is made from welded profile wire on supports designed according to data sheet provided by the customer. This assembly is an anti-clogging process because the profile wire shape allows only two contact points and a large open area.

The Vee-wire internals are used principally for two below process.


  • Inlet distributor
  • Support grid
  • Collector Basket
  • Liquid Distributor Tray
  • Quench Mixing tray
  • Beams


  • Inlet distributor
  • Centerpipe
  • SCS Basket®
  • Scallops

The down flow reactor requires internal with very high resistance to collapse or buckling and Vee-wire screen exactly meet these constraints.

Due to their strength characteristics and their very long lifetime, internal in profile wire are used as media support in fixed bed reactors such as hydrocracking and desulfurizing.

Radial flow systems produce a smooth surface in contact with catalyst, a higher yield, less pressure drop across the bed and this advantages make it a high performance equipment that fits different process in high temperature such as: Ammonia converters, Catalytic reforming, Hydrodesulphurizing units and so forth.

Inlet distributor

In up flow reactor, inlet nozzle is necessary for uniform diffusion of the fluid. The inlet nozzle can be attached to the inlet flange or sitting between the two flanges to be removable According to reactor process and the flow dynamic, the inlet nozzle can have different design that are propose wedge wire screen, perforated sheet metal, corrugated sheet in order to give the best performance.

Support grid

The support grid is a retention device for the catalyst in axial flow reactors. The support grid must be designed to withstand loads of vertical processes. The support grid may have different designs which are proposed wedge wire screen reinforced by reinforcements or beams, according to process, in order to provide the best strength.


Liquid Distributor Tray

The fluid dispensing system in an axial flow reactor which plays a key role in the performance of the catalyst. The uniformity of flow distribution creates optimum conditions of catalyst use to obtain highpurity products.

Quench Mixing Tray

The multi-bed reactor process often requires a cooling phase between the beds and this could be done by the injection of liquid, which is then collected and mixed, before being redistributed to the next bed. Different designs are proposed depending on the process specification.


Scallops are modules fabricated of wedge wire screen or slotted plate, placed on the reactor wall vertically so that the filtration surface is toward the center of the reactor. It is a device to replace the outer baskets. Several forms are considered depending on process conditions and fluid dynamics. 

SCS Basket ®

SCS Basket ® increases process performance and reduces operating and maintenance costs in refineries and petrochemical plants. SCS Basket ® is a catalyst support for radial flow reactors and was designed to have a high mechanical strength and facilitate installation in the catalytic reactors. SCS Basket ® replaces classic outer basket and scallops-, to improve the performance of catalytic reactors over the time. SCS Basket ® is presented in form of longitudinal hollow conduits which are distributed on peripheral ring around a volume containing catalyst bed.

Thermal expansion

SCS Basket® is designed to have high mechanical strength under fast temperature variations. The gap between the front and back face of two adjacent elements allows differential thermal expansion.

Contact surface

The surface in contact with catalyst is made of Wedge Wire Profile having slots along the reactor axis. Therefore, the inside face of the SCS-Basket presents a smooth surface, which prevents catalyst damage.

Elements assembly

The special saw-tooth connection is secured by use of Allen bolt. For maximum security we use an Allen bolt, which is embedded in matter of vertical and horizontal bars so no disruptive element penetrates into the catalyst bed, so as to ensure a smooth surface of contact with the catalyst.

The SCS Basket ® advantages

  • Designed in sectors to pass through manholes
  • Constitute a cylinder to create uniform catalyst bed
  • High gas flow
  • High mechanical strength
  • Self-supporting envelope (bursting)
  • No contact with the inside of the reactor
  • No conflict with the reactor wall during thermal expansion
  • Easy assembly and dismounting
  • Bottom sectors can be dismounted easily during maintenance


The Centerpipe is a cylindrical element placed in the radial flow reactor center to collect or distribute the flow. This is a key device of the process; its design should be perfectly mastered mechanically and hydraulically. HMDS Process specializes in catalytic reactor internal of Centerpipe , mechanically incorporating finite element analysis results by evaluating the transfer of charges between the different parts and the professionally made operational units. The Centerpipe in wedge wire screen is fabricated following a review procedure for all critical aspects of life, respect for the open area, slot size by calibration and overall dimensional control. 

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