Liquid distributor tray Liquid distributor tray ensure uniform iquid-gas flow distribution in the catalyst bed.it facilitates effective utilization of the entire catalyst inventory and minimizes radial temperature gradients,which can result from non-ideal flow.
Whether in up-flow or down-flow operation,uniformity of flow distribution is a key to even transit time,catalyst consumption and catalyst deactivation.In optimum conditions,plug flow is managed in order to obtain high purity products.

Distribution is critical under two-phase flow when liquid and gas are mixed,the pattern of liquid spreading in the gas orgas diffusion into the liquid is essential to chemical processes.The liquid distributor system has to perform equally against versatility of inlet flow.
Pressure drop must be controlled for its contribution as a flow reducing factor.Distribution is more critical for high pressure reactors where height saving signiticantly reduces the equipment costs or for revamp where increased capacity is required for increased inlet flow to bed.
Flow is distributed via several distribution nozzles connected to the distributor tray.Each distributor nozzle is a flow restriction using venturi effect to perform its duty.Nozzle spacing,pattern and type are particular to each application.

▶Custom design that fit the application or detailed design as perspecification.
▶Hydraulicand mechanical design foreach process.
▶ Tight manufacturing tolerances on panel flatness.
▶ Trial assembly at Seliwei screens shop is a standard control assessed by a report which is given dimensions that have to match vessel as-buit dimension.
▶To ensure good performance of equipment,liquid distributor will be tested on our test stand in SLw shop at client request.
▶To ensure that all requirements are applied during installation,Seliwei screens will provide technical assistance for onsite operation at  customer's  site.

Support grid is a retention device for the catalyst which is extending through the entire cross section of the vessel.
The catalyst loading diagram is the general scheme with the sequence of the inert balls and different types of catalyst.Under axial flow operations,the support grid assembly has to withstand vertical process loads.The grids have to be reinforced or supported by extra beams adding extra strength to the assembly.

Design and operating temperature,pressure drop through the catalyst,opening size and percentage of open area are necessary process parameters to design support grid.
Additional conditions upon change of flow direction and process cycles are required to define type of grid assembly.

To retain weight of support grid,T or I shape beams are alternatives for support beams.
T-beams generally are used for high design pressure allowing the possibility to immerge the important height of the web inside the bed.
I-Beams on the contrary is more commonly used for lighter design pressure,allowing to position the beams below the grid.

Outlet collector is a retention device for catalyst by collecting the flow from the reactor towards the outlet nozzle to achieve optimal catalyst utilization.
It can be placed either buried below an inert balls bed which filled the bottom part of the reactor/drier or below a support grid to distribute outlet flow.
Outlet collector will be also be designed as final retention device to avoid media migration out of vessel.

Outlet collectors can come in several shapes as per process condition and fluid dynamics, generally it has a cylindrical shape but conical shape and hemispherical shape are also applicable.
One of the most important parameter in design of outlet collectors is providing required open area than outlet nozzle section. Sealing all around the collector is necessary to avoid media migration.
According to reactor process and flow dynamic,it can have different design that are proposed V-Wire screen, perforated sheet, slotted sheet in order to reach the best performance.
Static and dynamic loads both are mechanically necessary to define the reinforcement.

In multiple beds reactors,process may require a cooling down phase between two beds.
This could be carried out by the injection of fluid,and vortex mixing tray to ensure efficient heat and mass transfer between the cold quench gas,vapor and liquid effluent from the upper catalyst bed.
The mixing chamber and the collection tray define a two-phase mixing volume.The passage way conducts fluid from above the collection tray into mixing chamber.The mixing chamber preferably includes at least one outlet opening for the downward passage of fluid.

Design and operating temperature,liquid and gas flow rate with their physical characteristics upon quench design being critical for process performance,the process licensor is defining the type and quantity of spray nozzles,with their configuration(Simple perforated ring pipeor header with lateral pipe).
Regarding the collection tray,the quantity,shape and cross area of outlet opening have to be designed based on specification while also the mixing chamber size and shape depend on process parameters,as far as resident time is impacting the efficiency of the mixing.

LATERAL DISTRIBUTOR
Lateral distributor or collector consists of branches and a header pipe or a hub and leads to provide an excellent collection or distribution of gas or liquid within treatment bed.
It can be located on top of vessel attached to inlet nozzle to distribute incoming flow entirely across the bed or near the vessel bottom to collect treated flow and to pass it though side wall orto be located on outlet nozzle to pass treated flow out of the vessel.
Header size, quantity and size of branches will be designed for each process based on flow rate, velocity and bed size.
These type of distributor/collector has a wide range of application such as:
Hydro-carbon processes(e.g.:MTBE,MEROX,PTA,Sand filters and Anthracite filters)
industrial Water Treatment with ION Exchanger,Activated Carbon Filter and Sand Filters.
Food processing as de-colorization for syrup, chromatographic column.
Laterals will have different design based on required mechanical resistance as per spec. and collection/distribution efficiency.
-V-Wire Screen Lateral fabricated from V-Wire screen while they can have different slots along the length of laterals to enhance flow distribution.
-Pipe-Base Screen fabricated from perforated pipe with welded V-Wire screen jacket where more mechanical resistance is needed.
-Dismountable Pipe-Base Screen which slip-on V-wire screen jacket can be dismountable to enable the possibility to remove it for probable maintenance operation in those corrosive processes.

SLW ADVANTAGES
Custom design that fit the application or detailed design as per specification.
Flexibility on design where slot opening can bevaried up to 30μ.

SCALE TRAP
It is a set of V-Wire screen baskets for below functions:
-To trap scale or any contamination coming from installation and maintenance.
-To increase bed surface contact of the gas or liquid.
-To avoid surface coking.
Scale traps generally used in Hydrogenation processes.
Normally a set of several concentric rings attached to V-Wire screen baskets will be located on top of reactor.While basket dimensions are in a range from 120mm to 200mm in diameter and 500mm to 900mm in height.Basket slot openings normally vary from 0.8mm to1.5mm.