Case Study · National Energy Infrastructure

40 m³/h Diesel Filtration at -30°C:
Protecting China’s Largest Onshore Oilfield’s Winter Fuel Supply

Cold-climate customised Jingyuan system — Daqing Oilfield fuel depot, Heilongjiang Province, China (CNPC)

Project Overview

1. The Challenge: Fuel Quality and Equipment Reliability Under Extreme Cold

Daqing Oilfield’s Heilongjiang location imposes operating conditions that simply do not exist in temperate industrial environments. Four compounding challenges defined the technical requirements for this project.

Ice crystal formation risk at -30°C

Heilongjiang winters are prolonged and severe. Even trace quantities of dissolved or free water in diesel fuel — quantities that would be harmless in warmer climates — can precipitate as ice crystals at the moment of tank discharge in -30°C ambient conditions. Ice crystal contamination in outbound fuel represents a direct threat to downstream vehicle fuel systems: blocked filters, seized injectors, and stalled engines in remote oilfield operating environments.

Pipeline scale from aged oilfield infrastructure

As a mature oilfield with decades of pipeline infrastructure, portions of Daqing’s internal fuel distribution network carry oxidised pipe scale — iron oxide flakes dislodged by flow velocity from aging steel pipe walls. At 40 m³/h loading flow, this scale is reliably entrained into the outbound fuel stream, creating both particulate contamination and a recurring maintenance burden on downstream vehicle fuel filters.

Winter supply continuity — a strategic obligation

Winter is Daqing Oilfield’s critical fuel supply period: heating oil, vehicle fuel, and generator diesel for oilfield operations all peak simultaneously with the onset of severe cold. Any interruption to the loading gantry — including a frozen or blocked filter system — directly impacts oilfield operational continuity. The filtration system was required to operate without interruption across the full winter season, regardless of ambient temperature.

CNPC HSE vendor qualification requirements

CNPC (China National Petroleum Corporation) operates one of the most rigorous vendor qualification systems in China’s energy sector. Health, Safety, and Environment (HSE) certification, explosion-proof compliance, and quality management system requirements must all be met and documented before any supplier can deploy equipment in CNPC operating areas. Standard industrial filtration products that lack ATEX/explosion-proof certification cannot operate in fuel depot environments under CNPC standards.

2. The Solution: Cold-Climate Engineered 40 m³/h Jingyuan System

Enhanced coalescence dehydration for ice crystal prevention

The system’s hydrophobic membrane phase separation stage is configured for enhanced performance targeting micro-water droplets and dissolved water — the forms of water contamination most likely to precipitate as ice crystals at sub-zero temperatures. Outbound diesel water content is reduced well below the national standard threshold, eliminating the physical precondition for ice crystal formation in downstream vehicle fuel systems.

Cold-climate engineering — materials and thermal provisions

Critical valves and seals are specified in low-temperature rated materials maintaining flexibility and sealing performance at -30°C. The filter housing incorporates pre-installed trace heating jacket connections, allowing the depot’s existing heat tracing system to maintain filter body temperature above the fluid viscosity threshold during extreme cold periods. This eliminates the risk of filter cracking or fluid flow restriction during Heilongjiang’s most severe winter conditions.

High-capacity gradient scale trap

A dedicated high dirt-holding capacity coarse filtration stage precedes the precision membrane elements. This gradient trap is configured to intercept the large-particle iron oxide scale from the aged pipeline network — protecting the precision coalescence membrane from premature loading and extending the service interval between regeneration cycles. The two-stage architecture separates the scale removal function from the precision dehydration function, optimising performance of both stages independently.

Ex d IIB T4 explosion-proof specification

The complete system — electrical components, motor, junction boxes, and instrumentation — is specified and certified to Ex d IIB T4 explosion-proof standard as required by CNPC’s HSE requirements for fuel depot environments. This certification was a prerequisite for CNPC vendor qualification and a mandatory requirement for operation in the fuel vapour environment of the Daqing loading gantry area.

3. Results

4. Customer Statement

“In Daqing, equipment must withstand the ‘Iron Man’ test — it has to work in the freezing cold without fail. Jingyuan’s 40 m³/h system has proven its worth during our toughest winter months. It effectively removes pipe scale and moisture, ensuring that the fuel we supply lives up to the Daqing Oilfield name.”

— Equipment Maintenance Director, Daqing Oilfield Sales Branch, CNPC

5. Technical Notes: Cold-Climate Filtration Engineering

At what water content does diesel ice crystal formation become a risk?

Free water in diesel begins to form ice crystals at approximately 0°C, but dissolved water can remain in solution to lower temperatures before precipitating. At -30°C ambient, even 200–300 ppm free water in outbound diesel presents a meaningful ice crystal risk in vehicle fuel systems, particularly when fuel passes through cold metal pipework between the storage tank and the engine fuel rail. Reducing free water to below 50 ppm effectively eliminates this risk across the full winter temperature range experienced in Heilongjiang.

Material selection for sub-zero filtration equipment

Standard carbon steel used in most industrial filtration equipment becomes brittle below approximately -20°C — a phenomenon known as ductile-to-brittle transition. At -30°C, standard steel filter housings and valve bodies face fracture risk under normal operating pressure. Cold-climate specification requires the use of low-temperature impact-tested steel (such as A333 Grade 6 or equivalent) for pressure-bearing components, along with elastomeric seals specified for low-temperature flexibility (HNBR or PTFE compounds rated to -40°C).

Relevance to other extreme cold petroleum applications

The Daqing engineering specification is directly applicable to fuel filtration requirements across Russia’s Siberian oilfields, Kazakhstan’s northern petroleum infrastructure, Canadian oil sands operations, and Scandinavian offshore support logistics — any environment where ambient winter temperatures reach -25°C or below and fuel system reliability is operationally critical. Jingyuan’s cold-climate configuration is available across the full JY product range.

Shenyang Jingyuan Membrane Systems Co., Ltd.  |  filtration-system.com/contact  |  info@jingyuan.hk  |  +86 138 8931 0698