Unbonded Composite Flexible Riser for Deep-Sea Wear and Pressure
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Solution Overview
Problem
Existing deep-sea mining flexible risers face challenges such as high weight density, poor wear resistance, and poor corrosion resistance, which limit their effectiveness in ultra-deep water environments.
Innovation Solution
A nonmetallic unbonded flexible riser is designed with a specific layered structure, including a lining layer, internal pressure resistant reinforcing layers, anti-wear layers, compensation reinforcing layers, tensile reinforcing layers, and outer coating layers, all with unbonded connections to enhance flexibility and resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If metal unbonded flexible riser is used, then strength and pressure resistance are improved, but weight density increases and corrosion resistance deteriorates
Solution Approach 1:
The patent uses composite materials throughout the riser structure. The lining layer uses ultra-high molecular weight polyethylene composite, the pressure bearing layer uses polyester resin matrix composite with fiber reinforcement, and the protective layer uses polyvinyl chloride composite. This composite material system provides both strength and corrosion resistance while reducing weight compared to metal alternatives.
Solution Approach 2:
The patent changes the material parameters from metal to nonmetallic composites. Specifically, it transitions from metal-based pressure resistant armoring to polyester resin matrix composite materials, fundamentally altering the density, strength-to-weight ratio, and corrosion resistance parameters of the riser system.
2Weight of moving object
If nonmetallic bonded flexible pipe is used, then weight density is reduced, but fatigue resistance deteriorates and bending radius requirements cannot be met
Solution Approach 1:
The patent segments the riser into multiple unbonded layers including lining layer, pressure bearing layer, and protective layer. Each layer functions independently without bonding to adjacent layers, allowing relative movement and rotation during bending and fatigue cycles, thereby improving fatigue resistance while maintaining light weight.
Solution Approach 2:
The unbonded structure enables dynamic response to bending and loading conditions. The layers can rotate and move relative to each other, providing flexibility and adapting to varying operational conditions without compromising structural integrity or fatigue life.
3Ease of operation
If nonmetallic flexible pipe with thermoplastic materials is used, then flexibility is improved, but permanent deformation occurs under large stress
Solution Approach 1:
The patent changes the material parameter from thermoplastic to thermosetting resin matrix. The polyester resin matrix composite material in the pressure bearing layer provides high strength and resistance to permanent deformation, while the unbonded layered structure maintains flexibility through inter-layer movement rather than material ductility.
4Ease of manufacture
If existing nonmetallic flexible pipe structure is used, then manufacturing complexity is reduced, but adaptability to ultra-deep sea environment deteriorates
Solution Approach 1:
The patent employs specialized composite materials suited for ultra-deep sea conditions: ultra-high molecular weight polyethylene for wear resistance, polyester resin matrix for strength-to-weight ratio, and polyvinyl chloride for corrosion and environmental resistance. These composite materials enable adaptation to 6000m depth while maintaining structural integrity.
Solution Approach 2:
Different layers have locally optimized properties: the lining layer has high wear resistance for mineral transport, the pressure bearing layer has high strength-to-weight ratio for deep water pressure, and the protective layer has corrosion resistance for seawater exposure. Each layer's composite material is specifically tailored to its functional requirements.
Data Source
AI summary
The present invention relates to a nonmetallic unbonded flexible riser for deep-sea mining and a manufacturing method thereof, wherein the riser includes a lining layer, an internal pressure resistant reinforcing layer, a first anti-wear layer, a first compensation reinforcing layer, a second anti-wear layer, a second compensation reinforcing layer, a third anti-wear layer, a framework layer, a isolation layer, a first tensile reinforcing layer, a fourth anti-wear layer, a second tensile reinforcing layer and an outer coating layer which are sequentially arranged from inside to outside, wherein unbonded connection between adjacent layers is adopted. The present invention may ensure the continuous transportation of the mineral and the seawater inside the flexible mixed transportation pipe, adapt to the severe marine environment and loading condition, and ensure the safety of mining work.