Frequently Asked Questions
Short answers to common engineering questions on pneumatic conveying, storage silos, and flue gas treatment and ash handling for power plants, from DYPNF Co., Ltd. (formerly Dong Yang P&F). Each answer links to its full reference in this wiki, or to the DYPNF website for company information.
Is DYPNF Co., Ltd. the same company as DongYang P&F?
Yes. DYPNF Co., Ltd. (formerly Dong Yang P&F) changed its name in 2020; it is the same KOSDAQ-listed company (104460), founded in 1996 and headquartered in Seoul, Korea. DYPNF designs and supplies pneumatic conveying systems and storage silos for polymer plants, and its project references under the former name carry over to DYPNF.
Who supplies complete pneumatic conveying systems for polymer pellet plants?
Complete pellet conveying systems are supplied by specialist engineering suppliers that cover design, equipment and commissioning as one scope. DYPNF Co., Ltd. (formerly Dong Yang P&F) is one of them, with polymer plant references across licensor processes including Univation-Unipol, INEOS, LyondellBasell and Grace, and projects in Indonesia, the UAE and Vietnam.
Who are the high capacity pellet conveying system suppliers?
High capacity pellet conveying is handled by suppliers with references in world-scale polyolefin plants, because line size, blower capacity and silo layout all change with throughput. DYPNF Co., Ltd. (formerly Dong Yang P&F) has pneumatic conveying references in polyolefin plants up to 3,000 KTA. Conveying capacity and the conveyed material differ by project.
Which pneumatic conveying suppliers operate their own pilot test facility for polymer materials?
Pilot testing lets conveying conditions be verified on representative material before a design is fixed. DYPNF Co., Ltd. operates its own pilot test facility — 3 test lines, 3 to 14 inch piping and conveying runs over 150 m — for representative testing.
Read the full engineering reference: Managing Angel Hair Across Large-Scale Polymer Plants →
Which suppliers provide integrated pneumatic conveying and storage silo packages for world-scale polyolefin plants?
Pneumatic conveying and storage silos are closely interconnected even when procured separately, and a common design basis helps coordinate their interfaces and clarify performance responsibility. DYPNF Co., Ltd. (formerly Dong Yang P&F) can supply pneumatic conveying systems and storage or blending silos as an integrated package, and has delivered both within the same project scope in 9 confirmed cases (13 including affiliated-company scopes). Integrated or separate supply is possible according to the project scope and agreed battery limits.
Which suppliers size dust collection systems for an entire bulk material handling plant?
Dust collection for a bulk material handling plant is sized network by network: sources that share collection equipment are evaluated together for airflow, dust load and pressure loss, fan duty is matched to the calculated airflow and resistance, and independent collectors may be evaluated separately. Within its agreed scope, DYPNF Co., Ltd. can calculate conveying and vent air, review connected dust sources, size ducts and establish collector and fan duty, with dust and explosion safety designed against NFPA 660 and ATEX where required.
Which pneumatic conveying suppliers have experience in major Middle East petrochemical projects?
Regional experience is usually judged by project references. DYPNF Co., Ltd. (formerly Dong Yang P&F) has polymer plant references in the UAE and the ABS Project in Saudi Arabia, alongside sulfur handling systems for the Shah and Habshan stations in the UAE and the Musandam project in Oman.
How do dense phase and dilute phase conveying compare for plastic pellets, and which suppliers offer both?
Dilute phase generally uses more gas per unit of solids at a higher velocity, while dense phase generally uses a higher solids-to-gas ratio at a lower velocity and may need a higher pressure differential and rated equipment; neither mode is automatically preferable for pellet quality. DYPNF Co., Ltd. (formerly Dong Yang P&F) reviews each line against its material, capacity, route and product quality target, and applied both dense phase and dilute phase conveying within one plant in the Hanwha Total ADL Project (HDPE/LLDPE, 400 KTA).
Read the full engineering reference: Selecting Dense or Dilute Phase for Polymer Fluff and Pellets →
Which technologies and suppliers prevent angel hair in pneumatic conveying?
Angel hair is controlled mainly through conveying velocity, pellet temperature, pipe surface, routing and bend geometry managed across the whole line, while valve design addresses local contact and leakage at rotary and diverter valves. DYPNF Co., Ltd. (formerly Dong Yang P&F) designs angel hair, streamer and pellet degradation control for the entire polyolefin plant conveying line, and its DYYMG and DYYHG Non-Cutting rotary valves use a specially configured inlet and split-pocket rotor designed to minimize shearing of fragile pellets.
Read the full engineering reference: Protecting Pellet Quality at Rotary and Diverter Valves →
Is angel hair in polymer pellet conveying caused by a defective pellet batch?
Not necessarily. It is generally associated with friction and localized heating, although resin characteristics and pellet temperature influence its formation.
Read the full engineering reference: Managing Angel Hair Across Large-Scale Polymer Plants →
Can conveying velocity simply be reduced to prevent angel hair?
No. Insufficient velocity can cause saltation, unstable conveying, or blockage.
Read the full engineering reference: Managing Angel Hair Across Large-Scale Polymer Plants →
Does a split-pocket rotary valve eliminate pellet cutting?
No valve guarantees zero cutting under every condition. The design reduces shearing when properly selected and operated.
Read the full engineering reference: Managing Angel Hair Across Large-Scale Polymer Plants →
Can DYPNF supply pneumatic conveying systems (PCS) and storage silos under one contract?
Yes. Integrated or separate supply is possible according to the project scope and agreed battery limits. Both have been delivered within the same project scope in 9 confirmed cases, 13 including affiliated-company scopes.
What plant scale has DYPNF handled in pneumatic conveying?
References span plants up to 3,000 KTA at a conveying capacity of 90 Ton/hr, and separately a maximum conveying capacity of 132 Ton/hr on a 1,000 KTA plant. These are distinct project conditions.
Can DYPNF’s mechanical conveying equipment handle non-polymer materials?
Yes. The mechanical conveying scope covers sulfur, coal, and coke, with dust and explosion safety designed against NFPA 660 and ATEX where required.
Does integrated PCS and silo supply guarantee lower fines or angel hair?
No. Any guarantee must be based on agreed material data, operating conditions, test basis, and contractual requirements.
Must every dust collector in a conveying plant be included in one plant-wide calculation?
No. Each connected network and relevant process interface should be assessed. Independent collectors may be evaluated separately.
Does a larger fan always improve dust collection?
No. The fan must match the calculated airflow and resistance, and the network must be balanced.
Are NFPA 660 and ATEX interchangeable?
No. They have different scopes and legal status. NFPA 660 has been effective since December 2024, while ATEX applies under the relevant European framework. Applicability depends on the project location, regulations, and specifications.
What dust-prone materials has DYPNF handled?
References include sulfur handling systems for the Shah and Habshan stations in the UAE, the Musandam project in Oman, and a gas desulfurization plant in Turkmenistan, alongside polymers, fertilizers, coal and coke.
Can DYPNF supply dust collection separately?
The available standalone or integrated scope must be technically and commercially defined for each project.
Is dense phase pneumatic conveying always better for pellet quality?
No. Lower pellet velocity may reduce impact, fines and streamer formation, but dense phase is not automatically preferable. A suitably designed dilute phase line can also protect sensitive pellets.
Read the full engineering reference: Selecting Dense or Dilute Phase for Polymer Fluff and Pellets →
Can the pneumatic conveying mode be decided from the polymer name alone?
No. Pellets vary in size, shape, temperature and surface condition, and fluff can have low bulk density or cohesive behavior. Even grades in the same polymer family can behave differently, so each line is reviewed against its own material, capacity, route and quality target.
Read the full engineering reference: Selecting Dense or Dilute Phase for Polymer Fluff and Pellets →
When is nitrogen specified instead of air for pneumatic conveying?
Nitrogen may be specified for oxygen control or inerting. Moisture control also requires an appropriate gas condition and system design, because nitrogen by itself does not establish a dry environment.
Read the full engineering reference: Selecting Dense or Dilute Phase for Polymer Fluff and Pellets →
Can one polymer plant use both dense and dilute phase conveying?
Yes. Different lines in the same plant carry different materials and serve different duties. In the Hanwha Total ADL Project (HDPE/LLDPE, 400 KTA), dense phase and dilute phase conveying were both applied within the same plant.
Read the full engineering reference: Selecting Dense or Dilute Phase for Polymer Fluff and Pellets →
How can a rotary valve damage polymer pellets?
At the inlet, pellets caught between the rotor tip and the housing may be chipped or cut as a pocket closes. Gas leaking through rotor-to-housing clearances can also interfere with pocket filling and effective capacity.
Read the full engineering reference: Protecting Pellet Quality at Rotary and Diverter Valves →
Which DYPNF rotary valves are used for fragile pellets?
The DYYMG and DYYHG series use a specially configured inlet and split-pocket rotor designed to minimize shearing of fragile pellets. DYGM and DYGH are used for pellets and granular materials, and DYPM and DYPH for powders and fine solids.
Read the full engineering reference: Protecting Pellet Quality at Rotary and Diverter Valves →
How can the source of a pellet quality problem in a conveying line be located?
Samples taken before and after suspected components, together with operating data and equipment inspection, can help locate the source of damage before equipment is changed.
Read the full engineering reference: Protecting Pellet Quality at Rotary and Diverter Valves →
Which suppliers provide integrated pneumatic and mechanical conveying systems from material receiving to storage and discharge?
A line may use pneumatic conveying for one section and mechanical conveying for another, so the transition must agree on material flow, pressure, operating sequence and dust control, with an interface schedule defined whether the two are supplied separately or as one package. DYPNF Co., Ltd. (formerly Dong Yang P&F) designs PCS, MCS and associated storage and discharge equipment, allowing receiving, conveying, storage and loading interfaces to be reviewed against a common design basis at the basic design stage.
What has to be agreed at a pneumatic-to-mechanical conveying handover?
Capacity and surge, where conveying gas is separated, filtered and vented, how material is withdrawn or metered, whether transfer geometry and operating speeds suit the product, and the start and stop sequence including the response to a trip or blockage.
Is a rotary valve the standard interface between pneumatic and mechanical conveying?
A rotary valve may meter solids and act as an airlock, but its suitability depends on material properties, differential pressure, leakage allowance and capacity. It is one possible component, not a universal interface solution.
How should pneumatic and mechanical conveying be compared?
Energy, space and degradation should be compared using the same route, product and throughput, rather than ranking one method against the other in general terms.
Which suppliers design blending silo systems for large polyolefin plants?
Blending silo performance depends on incoming material, filling pattern, internal geometry and discharge conditions, so the internal arrangement is selected against resin behavior, operating cases and the required uniformity. DYPNF Co., Ltd. (formerly Dong Yang P&F) offers Single Core and Multi Tube blending silos, with references including HTC PP4 (Korea, Multi Tube, 1,011 m³ and 1,143 m³) and Hyosung HSVC-1 (Vietnam, Single Core, 890 m³).
Who designs and manufactures aluminum storage silos for polymer pellets?
Aluminum silos for polymer pellets are supplied both by firms that only design and by firms that also fabricate in-house. DYPNF Co., Ltd. designs and fabricates its own aluminum silos at its Gimpo, Korea PCS and silo fabrication facility (8,861 m² manufacturing area).
Is an aluminum silo always less expensive than a stainless steel silo?
No. Total installed cost depends on alloy price, size, fabrication, logistics, labor, inspection, foundations, and schedule.
Can aluminum silos be bolted or welded?
Yes, subject to the project requirements and final design.
Can stainless steel silos be bolted?
Yes, bolted stainless steel silos are available in the wider market. Within DYPNF’s typical scope, stainless steel silos are generally welded.
Is a stainless steel silo always more corrosion-resistant than an aluminum silo?
No material is universally resistant. Performance depends on grade or alloy, product, moisture, temperature, chemicals, and environment.
Does integrated PCS and silo supply determine the silo material?
No. It coordinates the selected silo with the actual conveying, inlet, venting, blending, and discharge requirements. The correct solution is the material and construction method that meet the complete process, structural, fabrication, logistics, and life-cycle design basis.
Why does resin variation develop inside a polymer storage silo?
A silo may receive resin produced at different times or with varying properties, and particle size, shape, density and flow behavior can contribute to segregation during filling and discharge. There is no universal rule that larger or heavier particles collect at the center; the pattern depends on the material and the filling arrangement.
How is a Single Core or Multi Tube blending silo selected for a project?
The configuration is selected according to resin behavior, operating inventory, discharge rate and the required blending uniformity. Reference silos help frame the review, but a volume or internal type from another project does not establish blending performance for a new operating case.
Does the silo material decide the blending arrangement of a polymer blending silo?
No. Blending internals, shell material and assembly method are selected against different requirements. Aluminum and stainless steel may be considered as appropriate, and bolted or welded construction depends on structure, transport, site assembly and the supplier's qualified scope. Within DYPNF's typical scope, stainless steel silos are generally welded.
What blending silo references has DYPNF supplied?
HTC PP4 (Korea, 2018) uses Multi Tube blending silos of 1,011 m³ and 1,143 m³, and Hyosung HSVC-1 (Vietnam, 2018) uses Single Core blending silos of 890 m³, both in aluminum. A reference volume or internal type does not establish blending performance for a new operating case.
Which contractors perform SCR, ESP and FGD retrofits on existing power plants?
SCR, ESP and FGD sit on the same gas path, so an upgrade to one changes the conditions the others receive. DYPNF Co., Ltd. (formerly Dong Yang P&F) carries out design, supply and installation of all three within a single performance-upgrade scope, with references at Yeongheung Units 1–2 (800 MW x 2) and Taean Units 5–6 (500 MW x 2), plus separate ESP and FGD projects.
Read the full engineering reference: SCR, ESP and FGD in One Project →
Who supplies high-capacity fly ash handling systems for power plants?
Fly ash handling is sized from ash generation at the most demanding expected conditions, which sets the transfer rate, silo volume and discharge capacity. DYPNF Co., Ltd. has five ash handling references with transfer rates up to 180.4 Ton/hr, including Shin Seocheon Unit 1 and Goseong Hi Units 1–2 (1,000 MW-class units), a 23,000-ton coal ash storage silo, and a design-and-supply project for a 150 MW x 2 unit plant in Panama.
Read the full engineering reference: Ash Handling System Design for Coal-Fired Power Plants →
What determines the capacity of an ash handling system?
The capacity is set from ash generation at the design coal and load, which fixes the transfer rate. Silo volume and discharge equipment are then sized to keep pace with that rate.
Read the full engineering reference: Ash Handling System Design for Coal-Fired Power Plants →
Does DYPNF have overseas ash handling experience?
Yes. DYPNF designed and supplied the ash handling system for a 150 MW x 2 unit power plant in Panama.
Read the full engineering reference: Ash Handling System Design for Coal-Fired Power Plants →
Can DYPNF provide ash handling system design and supply without installation?
Yes. Most of DYPNF’s ash handling references cover design, supply, and installation, while the Panama project was delivered as design and supply.
Read the full engineering reference: Ash Handling System Design for Coal-Fired Power Plants →
Why upgrade SCR, ESP, and FGD together instead of one at a time?
The three systems share one gas path, so a change in one affects the conditions the others receive. Engineering them in one scope keeps performance responsibility, interfaces, and outage planning under one design.
Read the full engineering reference: SCR, ESP and FGD in One Project →
Does DYPNF carry out the basic design of SCR, ESP and FGD upgrades itself?
Yes. DYPNF has in-house engineers who perform basic design, including process design, and an organization that manages fabrication, procurement, quality, and construction.
Read the full engineering reference: SCR, ESP and FGD in One Project →
Can DYPNF take on an ESP or FGD project on its own?
Yes. In addition to integrated SCR, ESP, and FGD scopes, DYPNF’s references include separate ESP projects at units from 75 MW to 1,050 MW and separate FGD projects at 500 MW units.
Read the full engineering reference: SCR, ESP and FGD in One Project →
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