An L-CNG plunger pump skid is a packaged system that transfers cryogenic liquid natural gas (LNG) from storage and raises its pressure before the LNG is vaporized and delivered as compressed natural gas (CNG). To select the right skid, match its flow capacity, discharge-pressure design, materials, controls, and interfaces to the station’s storage, vaporizer, dispensing, and site requirements. The pump is only one part of the decision: a well-matched skid must also work with the complete process and safety design. This guide helps station buyers and engineering teams organize those checks before requesting a quotation.
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This guide is intended for L-CNG station owners, EPC contractors, process engineers, and procurement teams comparing plunger pump skids. It is useful when preparing a new station, replacing or upgrading equipment, or checking whether a proposed package fits an existing site. The required information will vary by jurisdiction, station configuration, and vehicle-fueling requirements. Use the guide as a selection framework, then confirm final design conditions with qualified project engineers and applicable local requirements.
A plunger pump is a reciprocating positive-displacement pump. Its moving plunger draws LNG into a pumping chamber and displaces it at elevated pressure, subject to the pump design and operating conditions. In a typical L-CNG process, the pressurized liquid then passes through a vaporizer, where heat converts it to gas before delivery to the CNG system. The exact process arrangement may include additional valves, instruments, piping, and controls.
LNG is stored at cryogenic temperature; its normal boiling point is approximately -162°C at atmospheric pressure. This temperature is a useful reference for understanding why the pump inlet, seals, piping, and instruments must be selected for cryogenic service. Actual LNG temperature and pressure at the pump inlet depend on storage conditions and system design. Do not use the normal boiling point as a substitute for the project’s specified operating envelope.
L-CNG pump skids are used in stations that store LNG and convert it to high-pressure natural gas for vehicle fueling or other specified gas supply duties. A station may be designed around its expected demand pattern, storage capacity, dispensing arrangement, and available utilities. These factors influence the required pump flow, operating cycle, and level of automation. The pump package should therefore be evaluated as part of the station process rather than as an isolated catalog item.
Before selecting equipment, map the skid’s connections to the LNG storage tank, vaporizer, downstream gas piping, electrical supply, control system, and site drainage or vent arrangements where applicable. Confirm connection sizes and ratings, instrument signals, control responsibilities, and any required isolation or bypass provisions. Also establish the package boundary: different suppliers may include different valves, instruments, wiring, or auxiliary equipment. A written scope matrix helps prevent gaps between the skid, EPC package, and site installation.
| Specification | What to Confirm | Why It Matters |
|---|---|---|
| Flow capacity | Required delivery rate, operating range, and station demand profile | Supports an appropriate match between pumping, vaporization, and dispensing. |
| Pressure | Required discharge pressure, design pressure, and pressure-control approach | Determines suitability for downstream equipment and the station’s operating conditions. |
| Inlet conditions | LNG temperature, pressure, supply piping, and available suction conditions | Helps assess stable pump operation and inlet-side design. |
| Materials and sealing | Materials and seal arrangements specified for cryogenic LNG service | Provides a basis for reviewing compatibility with the process and maintenance plan. |
| Controls and instrumentation | Control modes, alarms, shutdown interfaces, and signal requirements | Clarifies integration with station controls and operating procedures. |
| Package scope | Included equipment, piping, documentation, testing, and support | Reduces uncertainty in procurement and site preparation. |
Pressure values must be tied to the applicable station design and fueling protocol. For unit comparison, 1 MPa equals 10 bar; for example, 20 MPa corresponds to 200 bar and 25 MPa corresponds to 250 bar. These are conversion examples, not a recommendation or universal pressure specification for an L-CNG pump skid. Ask the project engineer and supplier to distinguish operating pressure, maximum allowable or design pressure, and any transient or test conditions.
Prepare a process data sheet with the intended service, required flow, operating schedule, LNG inlet conditions, target discharge conditions, and downstream equipment. Include the station’s expected demand pattern rather than relying only on a single peak figure. Identify whether the skid will operate continuously, intermittently, or under varying demand, as applicable to the project. If some inputs are not yet fixed, label them as assumptions and ask suppliers to state how those assumptions affect their proposal.
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The pump’s output and the vaporizer’s capacity should be evaluated together across the intended operating range. Confirm that the proposed process arrangement addresses the station’s required gas delivery conditions and control strategy. Ask how the supplier defines rated capacity and which inlet and discharge conditions apply to that rating. Compare proposals on the same basis so that different assumptions do not appear to be equivalent specifications.
Request the proposed materials for pressure-containing parts, cryogenic piping, valves, and seals, and check them against the project’s process conditions. Review the skid layout for lifting, foundation, piping access, electrical connections, and maintenance clearance. A compact package may still require adequate space to inspect, isolate, and service components. Confirm dimensions and connection orientations against the site layout before equipment release.
Agree on who supplies the instruments, local panel, wiring, and control-system interfaces. Review the proposed alarms, permissives, shutdown signals, and restart procedure against the station’s operating philosophy and safety design. Do not assume that a supplier’s standard control scope will match a particular EPC or site standard. Record any exclusions and interface responsibilities in the technical bid evaluation.
There is no reliable universal price for an L-CNG pump skid because configuration, capacity, pressure design, materials, instrumentation, documentation, and testing scope can differ. Request a quotation based on a common data sheet and ask the supplier to separate included equipment from optional items and exclusions. Minimum order quantities, where relevant, depend on the supplier’s commercial and manufacturing arrangements and should be confirmed directly. Lead time should also be quoted against the agreed technical scope, drawing-approval schedule, and delivery terms rather than treated as a general catalog promise.
When evaluating Dongzhao as a potential supplier, share the project data sheet and request a written proposal that addresses these points. We can review the application requirements with your team and clarify the proposed equipment scope, interfaces, and information needed for technical evaluation. Confirm any specific manufacturing, inspection, documentation, or service requirements during the inquiry stage so they can be assessed against the project.
A frequent mistake is choosing a pump based on nominal pressure alone while leaving flow, inlet conditions, or the downstream vaporizer undefined. Another is comparing quotations with different package boundaries, which can hide missing instruments or installation interfaces. Buyers should also avoid treating a pressure conversion example or general industry value as a project specification. Finally, do not approve the skid layout before checking foundations, lifting access, pipe routing, utilities, and maintenance clearance.
The right L-CNG plunger pump skid is the one that fits the station’s LNG supply conditions, required flow and pressure, vaporizer, controls, and site interfaces. Begin with a project-specific data sheet, define the supplier’s scope, and compare proposals using consistent assumptions. Then have qualified engineering personnel verify the package against applicable design and safety requirements before purchase. To discuss a project with Dongzhao, send your process conditions, target duty, site interfaces, and requested documentation so we can help clarify the next steps for a technical inquiry.
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