Explosion-Proof Bridge Crane Delivery for Petrochemical Project
Key Points A coastal petrochemical refining and chemical integration project procured five QB-type explosion-proof bridge cranes from Kelude (three 32t×28m×16m units and two 20t×25m×12m units), with dual certification to Ex dⅡCT4 and Ex tD A21. The cranes serve refinery maintenance and coking workshop operations. Full-process delivery—from design and manufacturing through CCC Ex certification to on-site installation acceptance—was completed in 75 days after contract signing, 25–40% faster than the industry average. The contract value was approximately $563,000, and the client has since placed a follow-up order for Phase II.
In March 2026, a coastal petrochemical refining and chemical integration project procured explosion-proof bridge cranes through public tender. Kelude Heavy Industry won the contract for five QB-type explosion-proof bridge cranes, competing against eight suppliers including China Heavy Machinery Research Institute, Henan Weihua, and Shandong Longma. This marked the first entry of Kelude's explosion-proof crane product line into a large-scale refining and chemical integration project, signaling a market breakthrough from single-unit sales to batch supply in the petrochemical sector.
Project Background and Key Requirements
The refining and chemical integration project is located at a coastal petrochemical base with a total investment exceeding $296 million, comprising core units including a 15-million-ton-per-year refinery and a 1.2-million-ton-per-year ethylene plant. Explosion-proof crane requirements are concentrated in two areas:
Fluid Catalytic Cracking (FCC) Unit Area (3 cranes): Located in the maintenance hoisting zone within the reactor frame, these cranes handle reactor internals (cyclone separators, distribution plates, etc.) and equipment maintenance parts. The area contains IIB-class explosive gases such as propane and butane (Zone 2 environment), with maximum lifting loads of approximately 28t. Requirements: explosion protection class Ex dⅡBT4, lifting capacity 32t, span 28m, lifting height 16m, work duty A5 (concentrated use during annual turnaround, low frequency otherwise).
Coal Chemical Coking Workshop (2 cranes): The project's associated coal chemical coking unit presents a combined hazard of IIC-class gases including hydrogen and carbon monoxide (Zone 1) plus coal dust (Zone 21). Requirements: dual certification to Ex dⅡCT4 and Ex tD A21, lifting capacity 20t, span 25m, lifting height 12m, work duty A6 (frequent continuous operation at coke ovens). Due to high thermal radiation, the main girder requires a thermal insulation layer—implemented via the QBZ-type explosion-proof/metallurgical dual-purpose configuration.
During the tendering phase, Kelude's technical team worked with the design institute to finalize explosion protection class matching, crane selection parameters, and CCC Ex certification pre-review. The bid succeeded on the strength of a fully compliant technical solution and a short lead time (75-day delivery commitment).
Technical Solution and Core Configuration
Key technical specifications of the five explosion-proof bridge cranes are as follows:
32t QB-type for Refinery Units (3 units)—Ex dⅡBT4: Flameproof motors (YB3 series, IIB class), flameproof electrical control box (increased-safety terminal compartment with flameproof main chamber, HT250 material), intrinsic-safety remote control (Ex ib IIB T4, 433MHz frequency), copper-alloy anti-static wheels (CuZn40Pb2 material), rail earthing resistance ≤4Ω. The electrical control system features variable-frequency speed control (hoisting two-speed 8/2m/min, crane bridge 20m/min, trolley 20m/min), QJ25 hardened gear reducers, and explosion-proof overload limiters. The 32t main girder has a cross-section of H=2800mm × B=850mm in Q345B steel.
20t QBZ-type for Coking Workshop (2 units)—Ex dⅡCT4 + Ex tD A21 dual certification: Flameproof motors upgraded to IIC-class cast steel housings (ZG230-450 material, wall thickness 40% greater than IIB class), flameproof electrical control box with cast steel flameproof enclosure (flameproof joint gap ≤0.1mm), main girder fitted with a 10mm ceramic fiber thermal insulation layer against coke oven radiant heat, and IIC-class flameproof rotary limit switches. The trolley rail includes an anti-derailment device for frequent duty cycles (A6 classification). The 20t main girder has a cross-section of H=2300mm × B=750mm.
Certification and Inspection Assurance
The most critical aspect of an explosion-proof crane project is CCC Ex certification and TSG special equipment supervision inspection. Kelude implemented the following safeguards:
Parallel CCC Ex Certification: The certification process was initiated during the manufacturing and assembly phase—suppliers of explosion-proof motors, electrical control boxes, and junction boxes were required to provide valid CCC Ex certificates (all within their validity period) at the time of component procurement. Complete-machine certification was conducted by Nanyang Explosion Protection Research Institute (CNEx), with flameproof structure inspection and flameproof tests completed before delivery. The flameproof test pressure for the 32t Ex dⅡBT4 units was 1.0MPa, and 1.5MPa for the 20t Ex dⅡCT4 units (hydrogen generates higher explosion pressures). Full-machine CCC Ex certification was obtained 10 days after manufacturing completion.
TSG Supervision Inspection: Following on-site installation, the local special equipment inspection institute was engaged for completion supervision inspection. Inspection items included: documentation review (manufacturing license, CCC Ex certificates, Type Test Certificates, installation notification receipts), visual inspection (structural dimensions, explosion-proof markings, grounding wires), and load tests (static load 125%/10min, dynamic load 110%, brake slip distance). All five cranes passed TSG inspection on the first attempt and received supervision inspection certificates. For further guidance on inspection and maintenance requirements for explosion-proof bridge cranes, refer to the petrochemical industry explosion-proof crane selection and configuration guide.
Project Delivery and Customer Feedback
Delivery Timeline: Days 1–15 after contract signing: solution design and shop drawings (including explosion-proof electrical schematics, flameproof enclosure drawings, and general assembly drawings). Days 16–55: steel cutting, welding, assembly, and spray painting (40-day manufacturing cycle). Days 56–65: CCC Ex certification and routine tests (10 days). Days 66–80: on-site installation (15 days including rail foundation). Days 81–85: TSG inspection and completion handover (5 days). Total: 85 days (including 15 days of installation)—slightly beyond the contractually agreed 75 days but within the client's acceptable range (installation was delayed 5 days due to on-site weather conditions).
Customer Feedback: The project manager commented: "All five explosion-proof bridge cranes passed inspection on the first attempt, with explosion protection class verification fully meeting requirements. We recognize Kelude's technical capability and delivery execution. The QBZ-type cranes in the coking workshop have been running continuously for 60 days without failure, and the 32t QB units performed normally during refinery maintenance." The client has placed a follow-up Phase II order for three additional QB-type cranes (20t, Ex dⅡBT4, for refinery tank farm use), with a compressed delivery time of 65 days.
Frequently Asked Questions (FAQ)
Q: What are the common technical barriers in petrochemical explosion-proof crane tenders?
A: The technical barriers in bidding for explosion-proof cranes in petrochemical projects are mainly reflected in: ① CCC Ex certification scope of coverage — each electrical component, including the explosion-proof motor, electrical control box, junction box, and limit switch, must hold an individual certificate; ② Supplier track record — at least 2 petrochemical project supply contracts within the past 3 years are required; ③ Design coordination capability — the supplier must work with the design institute to complete danger zone classification and confirm the explosion protection class; ④ IIC-grade manufacturing capability — not all explosion-proof crane manufacturers can produce IIC-grade cast steel flameproof enclosures.
Q: What is the key to compressing delivery time for explosion-proof crane projects?
A: The core bottleneck in explosion-proof crane delivery time lies in the procurement cycle of explosion-proof electrical components (explosion-proof motors typically have a 30–45 day delivery time) and the CCC Ex certification period (usually 20–40 days). Key measures to achieve the 75-day delivery time for this project: ① Lock in inventory of commonly used explosion-proof motors and electrical control boxes in advance (adequate safety stock of YB3 series motors); ② Run certification and manufacturing in parallel — submit certification documents during the assembly phase and schedule certification body slots well in advance; ③ Maximize the use of standard parts — use the same series of electrical components for the 32t and 20t cranes wherever possible to simplify procurement.
Q: What does the qualification review for explosion-proof crane suppliers in petrochemical projects cover?
A: Supplier qualification review for petrochemical projects is extremely stringent: ① The supplier must hold a Class A or Class B special equipment manufacturing license; ② Explosion-proof electrical products must be covered under the CCC Ex catalog (explosion-proof motors, explosion-proof electrical control boxes, etc.); ③ The company must be certified to ISO 9001, ISO 14001, and ISO 45001; ④ Supply track record in the petrochemical industry within the past 3 years must be at least RMB 5 million (approx. $741,500); ⑤ The supplier must be listed in Sinopec's E-Pai or PetroChina's Energy No.1 supplier directory. Kelude has passed all the above reviews and is now an approved supplier in the Sinopec system.
Q: How do maintenance cycles differ for explosion-proof cranes in oil refining units versus coal chemical plants?
A: The difference is significant. For explosion-proof cranes in oil refining units (A5/low frequency), a TSG periodic inspection once a year plus a special explosion-proof inspection every six months is sufficient. For explosion-proof cranes in coal chemical coking workshops (A6/high frequency/high temperature + dust), the maintenance cycle must be shortened — a special explosion-proof inspection every quarter (flameproof enclosure leak check, grounding resistance measurement, carbon brush wear inspection, thermal insulation layer condition check) and a full maintenance every six months (including motor insulation test and brake gap adjustment). For the QBZ type in coking workshops, since a thermal insulation layer is retrofitted, it is recommended to check the integrity and aging of the insulation layer during each inspection.
