Depamu Chemical Injection Systems & Dosing Pumps for Oil & Gas

1. Introduction

In the extensive value chain of the oil and natural gas industry—from extraction and gathering to refining and transportation—every stage demands the precise injection of chemical additives. Whether it is demulsifiers, corrosion inhibitors, scale inhibitors, oxygen scavengers, biocides, or methanol (ethylene glycol) inhibitors, the ability to deliver these chemicals at accurate dosages, stable pressures, and reliable rates directly impacts production efficiency, equipment service life, and operational safety. Depamu (Hangzhou) Pumps Technology Co., Ltd. has established itself as a key player in this critical domain—a fluid handling equipment manufacturer that has grown from Hangzhou's Qiantang Area to become a globally recognized supplier.

2. Company Profile: A "Little Giant" from Hangzhou Going Global

Founded in 2003 and located in the Hangzhou Qiantang Area—a national-level economic and technological development zone—Depamu is a high-tech enterprise specializing in the research, development, production, and sales of fluid handling equipment. The company's name carries historical significance: the Chinese character "德" (De) reflects its origins in the early 1990s, when it introduced advanced Metering Pump and chemical dosing technologies from Germany.

Over more than two decades of dedicated development, Depamu has grown into a benchmark enterprise in China's fluid handling equipment sector. It has been recognized as a National Key Specialized and Sophisticated "Little Giant" enterprise and a National Intellectual Property Advantage Enterprise. The company's main product portfolio includes metering pumps (plunger-type, mechanical diaphragm, and hydraulic diaphragm), high-pressure Reciprocating Pumps (plunger, diaphragm, and hose-type), Screw Pumps, Rotor Pumps, centrifugal pumps, cryogenic pumps, as well as complete chemical dosing packages, water-steam sampling devices, supercritical fluid equipment, and water treatment systems.

All products are designed and manufactured in strict compliance with American Petroleum Institute standards API 674 and API 675, and have received certifications from internationally recognized authorities including DNV (Det Norske Veritas), ISO 9001 Quality Management System, and CE European Community Certification. The company has successfully applied for over 100 technical patents.

Today, Depamu's products are widely deployed across oil and gas field exploitation, petroleum refining and transportation, nuclear power, military projects, chemicals, power generation, pharmaceuticals, food processing, new energy, and environmental protection. The company maintains long-term strategic partnerships with China's major state-owned energy enterprises—CNPC, Sinopec, and CNOOC—and its products are exported to more than 50 countries and regions including the United States, the United Kingdom, France, Russia, Brazil, Germany, Australia, Iran, Turkmenistan, and Syria.

3. Chemical Injection Systems: The "Process Chemist" of the Oilfield

In oil and gas extraction, gathering, and refining, chemical injection systems perform the core function of precisely delivering various chemical additives into process media. Depamu's DPJY-series chemical injection skids are complete sets of equipment specifically designed for this purpose.

3.1 System Composition and Classification

Depamu's oil and gas field chemical additive injection systems are categorized by function into demulsifier Injection Packages, corrosion inhibitor injection packages, oxygen scavenger injection packages, reverse demulsifier injection packages, biocide injection packages, methanol (ethylene glycol) injection packages, as well as water injection and polymer injection systems. In the petrochemical sector, these systems are further细分 into scale inhibitor injection packages, desulfurizer injection packages, antioxidant injection packages, antistatic agent injection packages, anti-wear agent injection packages, polymerization inhibitor injection packages, and catalyst injection packages.

A typical injection skid consists of a solution tank, metering pumps, piping and valve systems, control systems, and a skid-mounted base. These can be configured in flexible combinations such as "1 tank + 2 pumps," "2 tanks + 3 pumps," or "2 tanks + 4 pumps. Solution tank volumes are customizable from 0.5 to 20 cubic meters to suit different operational requirements. The system is further composed of solution tanks, agitators, metering pumps, level indicators, safety valves, pressure gauges, pulsation dampeners, convectors, various valves, support bases, stairways and handrails, electrical control systems, complete piping, and auxiliary components.

3.2 Intelligent Control and High-Precision Dosing

Modern oil and gas production imposes increasingly stringent requirements on chemical injection accuracy. Depamu's injection systems can receive real-time parameters of process media through online instrument testing, automatically regulate the ratio between chemical injection volume and process medium flow (the PPM value), and simultaneously receive feedback data on the actual effect after chemical injection—achieving intelligent online closed-loop control of the optimal chemical injection volume with an accuracy better than ±1%. When equipped with a high-precision flow recorder or weightless flow control system, the chemical injection accuracy can reach ±0.5% to 0.2%, meeting the demands of high-precision chemical injection applications.

3.3 Modular Design and Flexible Customization

Depamu's injection systems adopt a modular design philosophy with integrated combination. This approach avoids the system inconsistencies that exist in traditional single-equipment or single-component designs and is based on a brand-new design concept that incorporates the essence of domestic and international dosing technologies. Users can flexibly select equipment configurations according to different media characteristics and operating conditions, and can choose components from well-known domestic and international brands. Multiple control modes—including manual and automatic—are available to meet various control requirements.

4. Metering and Dosing Pumps: The Core of Precise Chemical Delivery

The metering pump (dosing pump) is the core actuating unit of any chemical injection system. Depamu has built a comprehensive product line and accumulated deep technical expertise in this field.

4.1 Plunger-Type Metering Pumps

The DP(M)ZA and DPWA series plunger-type metering pumps are Depamu's flagship products for oil and gas field applications. Their operating principle is based on the reciprocating motion of a plunger, which cyclically changes the volume of the working chamber, driving the inlet and outlet check valves to complete the suction and discharge of fluid.

The key advantages of this series include:

• High-performance plungers with specialized packing seal assemblies, ensuring long service life and excellent sealing performance;

• High-precision inlet and outlet check valve assemblies, effectively guaranteeing metering accuracy and fluidity;

• Patented integrated sleeve-type adjustable eccentric transmission mechanism, allowing stroke adjustment within 0-100% range for stepless flow rate regulation, with metering accuracy of ±0.5% (within the 10%-100% adjustment range);

• Integrated "Oude" worm gear pair variable-speed transmission, featuring low noise and high efficiency;

• Oil-immersed lubrication, ensuring long-term reliable operation of transmission components.

Flow rate adjustment modes are diverse, supporting manual, electric, pneumatic, and variable frequency control. Remote automatic control can be achieved through electric stroke actuators. Single pump head flow rates can reach up to 12,100 L/h, with pressures up to 228 MPa. Pump head materials can be selected from 304, 316, 316L, 904L, Hastelloy C, and high-polymer materials depending on the media characteristics.

4.2 Diaphragm-Type Metering Pumps

For applications involving toxic, flammable, explosive, or highly corrosive media, Depamu offers mechanical diaphragm and Hydraulic Diaphragm Metering Pumps. The diaphragm technology ensures zero leakage of the medium, making it particularly suitable for transporting toxic, corrosive, and volatile fluids. The hydraulic diaphragm metering pumps feature limit valves with precision up to ±0.002 mm, and diaphragm surfaces with hardness reaching 60-70 HRC and roughness of 0.4 μm, capable of withstanding temperatures from -80°C to 160°C with a service life of 80 million cycles.

4.3 High-Pressure Reciprocating Pumps

For large-flow, high-pressure applications such as oilfield water injection, polymer injection, and alcohol injection, Depamu's HD series high-pressure reciprocating pumps play a vital role. Designed in accordance with API 674 standards, these pumps cover flow ranges from 0.35 to 96.89 m³/h with pressures up to 160.3 MPa. The HD3E(M) series, for example, offers flow rates from 0.76 to 10.74 m³/h with pressure ranges from 3.1 to 50.9 MPa. Plunger-type reciprocating pumps are particularly well-suited for high-pressure, large-flow conditions, delivering high efficiency and stable output flow that is unaffected by downstream pipeline pressure fluctuations.

Reciprocating pumps feature a compact modular structure, small footprint, and light weight, with good lubricity, low friction coefficient, and high efficiency. The drive end provides stable and reliable transmission with low noise. Installation forms include horizontal, vertical, stationary, and mobile configurations, with power sources ranging from motors and diesel engines to solar energy. Wetted parts can be manufactured from alloy steel, stainless steel, duplex steel, titanium, Hastelloy, and other materials.

5. Representative Application Cases

5.1 Uganda's First Oilfield Project – Kingfisher

In October 2023, Depamu successfully completed factory testing and delivery of 29 custom-engineered chemical injection skids for the Kingfisher oilfield development project in Uganda. Located in the western part of the East African Rift Valley and the southern part of the Albert Basin, the Kingfisher oilfield is Uganda's first commercial oilfield and the largest project invested by Chinese enterprises in the country.

Faced with Uganda's complex crude oil production processes and stringent localization requirements, Depamu established a dedicated project team to coordinate and oversee the effort. Drawing on extensive experience in oil and gas engineering equipment manufacturing, the team strictly adhered to production schedules and quality standards. The 29 chemical injection skids feature modular design with integrated combination, compact structure, attractive appearance, high automation, and flexible, convenient operation—fully meeting Uganda's demanding operational conditions. This successful delivery expanded Depamu's range of exported equipment and earned international recognition for the company's manufacturing capabilities.

5.2 CNOOC Offshore Platform Projects

In 2026, Depamu successfully delivered multiple sets of offshore platform chemical injection skids and high-pressure reciprocating pumps to CNOOC for deployment in oil and gas extraction operations in the South China Sea and Bohai Sea. These equipment sets achieved localized replacement of critical core technologies that had previously relied on imports.

Offshore oil and gas extraction presents extreme challenges: high temperatures, high humidity, and high salt spray corrosion demand exceptional corrosion resistance and stability from equipment. Faced with the space constraints of offshore platforms—where "every inch of space is precious"—Depamu's R&D team broke away from traditional single-layer layout thinking and innovatively adopted a three-tier skid structure. This design vertically integrates IBC tanks, storage tanks, and pump groups, reducing the footprint by 40% to 50% compared to conventional designs. This "building upward" approach not only solved the platform's spatial constraints but also leveraged height differentials to reduce pump cavitation risk and extend equipment service life. To address the corrosive challenges of marine environments, the team optimized welding processes, adopted full-penetration welding for critical structural steel joints, and upgraded to corrosion-resistant materials including duplex stainless steel and titanium.

6. Technical Advantages and Industry Value

The core value of Depamu's chemical injection systems and metering pumps in the oil and gas industry can be summarized in several key dimensions:

Precision Assurance: With metering accuracy of ±0.5% and intelligent closed-loop control systems, every drop of chemical additive is delivered with maximum effectiveness—preventing both chemical waste and inadequate dosing that could lead to equipment corrosion or process abnormalities.

Safety and Reliability: For flammable, explosive, and toxic media, Diaphragm Pump technology ensures zero leakage of hazardous substances. Explosion-proof design and remote control capabilities further enhance the safety of on-site operators.

Environmental Adaptability: From onshore oilfields in the East African highlands to offshore platforms in the South China Sea, Depamu's equipment has proven its resilience under demanding conditions. The three-tier skid design for offshore platforms exemplifies the company's engineering innovation under extreme spatial constraints.

Localized Replacement: For many years, China's high-end offshore equipment relied on imports. Depamu's domestically manufactured injection skids delivered to CNOOC represent a concrete step toward replacing imported equipment with locally developed technology, driving self-reliance in marine equipment.

7. Conclusion

From a pump manufacturer in Hangzhou's Qiantang Area to a National Key Specialized "Little Giant" with products deployed in more than 50 countries worldwide, Depamu's two-decade journey reflects the broader trajectory of China's fluid handling equipment industry—from follower to competitor, from technology importer to independent innovator. In the oil and natural gas sector—a strategically vital industry for national energy security—Depamu's chemical injection systems and metering pumps are delivering precision, reliability, and intelligence to oil and gas fields around the world, contributing the strength of "Made in China" to safe and efficient global energy production