Purchasing Experience and Analysis of Commonly Used Pumps

Pump equipment is a commonly used key equipment in oil and gas field surface engineering and plays an important role in the safe and stable operation of the project. Different pump types are used in different projects and situations. The procurement of pump equipment requires purchasers to understand and master every link, and no mistakes are allowed.

Based on the experience in procurement of oil and gas field surface engineering projects, this article introduces the types of pumps commonly used in projects. Aiming at the links that are prone to problems in the procurement process of pump equipment, the key points of its procurement work are analyzed, and the professional requirements of procurement personnel are analyzed. A summary is made to facilitate the development of procurement work.

Introduction

In oil and gas field surface engineering projects, pumps are the most commonly used fluid machinery. Various types of pumps are used in processes such as oil and gas gathering and transportation, crude oil and natural gas processing, oil pipelines and oil depots, and station public works. Different types of pumps are required in different processes, and reasonable selection should be made based on actual working conditions; at the same time, as an important rotating equipment in the procurement of materials for engineering construction projects, the procurement of pumps is particularly important.

In actual engineering projects, many problems will be encountered in the selection and procurement of pumps. Only by grasping the key points in the selection and procurement process can we master every aspect of the design and procurement process of pump equipment and prepare for oil and gas field surface engineering projects. Provide safe and reliable pump equipment.

Types of pumps commonly used in oil and gas field surface engineering projects

Oil and gas field surface engineering projects include wellhead facilities, oil (gas) gathering stations, oil transfer stations, central processing plants, water injection stations, long-distance pipelines, oil depots, natural gas processing plants, natural gas liquefaction plants and other projects as well as supporting public works. Different projects Different oil and gas treatment processes require different types of pumps. According to the classification of pump forms, the author summarizes the types of pumps commonly used in oil and gas field surface engineering projects as follows.

1. Centrifugal pump

Centrifugal pumps are the most widely used in the oil and gas industry. Centrifugal pumps have the characteristics of large displacement, high lift, high efficiency, convenient flow adjustment, and reliable operation. When the viscosity of the conveyed medium is small, the flow rate is large, and the lift is high, a centrifugal pump is suitable. According to different process functions and usage occasions, centrifugal pumps include water supply pumps, oil transfer pumps, water injection pumps, deep well pumps, submersible pumps, submersible pumps, sewage oil pumps, sewage pumps and other types.

In the crude oil central processing plant project, the transportation medium is mainly crude oil and oily sewage before and after treatment. The centrifugal pumps used are: oil transfer pump, stabilizing tower bottom pump, dehydration pump, oil unloading pump, oil feeding pump, condensate oil pump, low pressure vent pump Liquid tank pump, high-pressure venting liquid separation tank pump, circulating water pump, backwash pump, first-stage booster pump, treated water transfer pump, desalted water replenishment pump, etc.

In long-distance crude oil pipeline projects, the transmission medium is processed crude oil, and the pumps used in such projects are oil transfer pumps.

In the natural gas treatment plant project, the transportation medium is mainly heavy hydrocarbons and sewage extracted from natural gas. The pumps used include condensate oil transfer pumps, transfer pumps, vented liquid separation tank pumps, sewage oil pumps, lean amine liquid pumps, etc.

In the natural gas liquefaction plant project, the transmission medium is mainly refrigerant, natural gas dewatered water and liquid natural gas. The centrifugal pumps used mainly include lean liquid circulation pump, supplementary water pump, water circulation pump, butane unloading pump, and amine stripper reflux pump. , lean amine liquid pump, submersible liquid pump, etc.

In public projects, centrifugal pumps are mainly used in sewage pumps, sludge pumps, fire main pumps, fire pressure regulator pumps, etc.

2. Reciprocating pump

The reciprocating pump has the characteristics of self-priming, high efficiency, ability to transport viscous oil, and stable efficiency. It is suitable for transporting lubricating oil and fuel oil or transporting small flow liquids under high pressure. According to the piston form, reciprocating pumps can be divided into piston pumps, plunger pumps and diaphragm pumps. The most commonly used reciprocating pumps in oil and gas field surface engineering projects are plunger pumps and diaphragm pumps.

In crude oil gathering and transportation systems, plunger pumps can be used as oil transfer pumps; in crude oil central processing plant projects, plunger pumps are commonly used as crude oil re-injection pumps, drainage pumps, etc.

In oil and gas wellhead facilities and treatment plants, diaphragm pumps are commonly used as dosing pumps to inject corrosion inhibitors, inhibitors and other chemicals. While injecting chemicals into the medium, the volume of the chemicals can be measured and the volume adjusted. This is also known as Metering pumps.

3. Rotor pump

Rotor pumps include screw pumps, gear pumps, sliding vane pumps, etc. Screw pumps are most commonly used in oil and gas field surface engineering projects. They are characterized by simple structure and small volume; stable operation and uniform flow; no eddy currents are formed when transporting media. It can transport viscous oil and is not sensitive to viscosity, can transport a variety of media, and can achieve multi-phase mixed transport. In crude oil processing plants and pipeline projects, screw pumps are often used as crude oil mixing pumps.

Gear pumps are generally used to transport lubricating media. In pump stations and oil depots, gear pumps are used to transport viscous media such as lubricating oil and fuel oil.

The sliding vane pump has strong self-priming ability and can transport light fuel oil with low viscosity, such as gasoline, diesel, etc. Some sliding vane pumps can also transport viscous media such as crude oil.

In addition, several types of industrial pumps that have developed rapidly in recent years, such as magnetic pumps, canned pumps, high-speed pumps, etc., are gradually being used in the petrochemical industry. However, they are currently rarely used in oil and gas field surface engineering projects.

Analysis of key points for purchasing pump equipment

Pumps are rotating equipment. Compared with static equipment such as pressure vessels, they are more complex and involve more specialties. The purchase of pump equipment requires high professional quality of purchasing personnel, and there are some points that require special attention. Based on the experience of purchasing pump equipment in overseas oil and gas field surface engineering construction projects, the author took oil field external pumps as an example to summarize and analyze the key points for purchasing pump equipment, mainly including the following aspects.

1. Supplier selection

Pump equipment is generally purchased through bidding. The first step in the procurement process is to select appropriate suppliers. Different suppliers provide different types of products. According to the type of pump required by the project, corresponding suppliers are invited to participate in the bidding. Pump equipment purchasers need to be familiar with various types of pump manufacturers and understand their product ranges in order to accurately select bidding suppliers. Oilfield export pumps often use centrifugal pumps and screw pumps. Centrifugal pumps can be divided into OH type, BB type and VS type according to API 610 standards; screw pumps can be divided into single screw, twin screw and triple screw. The specific supply of each manufacturer The scope can be obtained through various methods such as the website, communication with suppliers and past cooperation experiences. On this basis, the suppliers to be invited to bid can be correctly selected.

2. Preparation of bidding documents

(1) Preparation of technical specifications

In the requisition documents and data tables of the technical bidding documents, the basic data need to be clarified, and the technical bidding documents must be prepared according to the data requirements. According to the physical parameters such as temperature, viscosity, and corrosiveness of the medium, the required flow rate and head, and the requirements for the material, the appropriate pump type is selected; in addition, the scope of supply and the brand requirements of the main suppliers also need to be technically determined. It’s clear in the document.

The purchase requisition document for oilfield export pumps includes project overview, adopted standards and specifications, scope of supply, design conditions, quality assurance and inspection tests, manufacturer data requirements, etc.; the data sheet includes crude oil fluid characteristics (density and viscosity, etc.), Operating condition requirements (inlet pressure, outlet pressure, NPSH, etc.), pump performance parameters (rated flow, power, etc.), motor data (speed, power, protection level, etc.), material requirements (casing, impeller, etc.) , mechanical seal and testing and inspection requirements.

For pump equipment, the mechanical seal is the key to ensuring its safe and stable operation and ensuring normal production operation; the flushing system is an important component to improve the operating environment of the mechanical seal and extend its service life. The technical documents can clarify the selection range of mechanical seals, whether to choose international brands or domestic brands. International brands are more reliable in quality, but more expensive; at the same time, it avoids manufacturers from using domestic brand seals to bid in order to win the bid at a low price during the business quotation process. After winning the bid, The phenomenon of claiming compensation from the purchaser occurs, which requires special attention during the technical bid evaluation. The mechanical seal brand also needs to be reviewed during the commercial bid evaluation process.

(2) Formulation of contract terms

Oilfield export pumps are similar to other pump equipment. The purchase contract usually adopts a lump sum contract (does not include on-site service costs. Since the on-site service time is uncertain, only the service rate is specified in the contract). The contract terms should at least include: Information, pump supply scope, price list, delivery date and trade terms, payment terms, quality assurance, etc. In addition, pump equipment usually requires on-site service. After the goods arrive at the site, the scope of installation and commissioning work, service rates, and service time calculations The method, etc. also need to be specified in the contract.

(3) Tender document format

Bidding documents mainly refer to the file format of commercial bidding documents. Like other material procurement, commercial bidding documents for oilfield pumps mainly include bid opening lists, itemized quotation tables, commercial deviation clauses, etc. In order to facilitate price analysis after the commercial bid opening, the itemized quotation table needs to list the key parts of the pump separately, such as pump body, mechanical seal, flushing system, motor, valve instrument, etc., to facilitate comparison of itemized equipment prices with market prices. , and also facilitates comparison of scope of supply.

3. Business bid evaluation process

(1) Confirmation of scope of supply

Confirmation of the scope of supply not only means that all materials and quantities should meet the technical requirements, but also the brand of the sub-equipment should also meet the limited requirements. For oil transfer pumps, it is necessary to ensure that there is no leakage of crude oil being transported, and the area where the pump is used has explosion-proof requirements. The main parts of the oil transfer pump, the mechanical seal and motor, must meet the technical requirements. Only if the scope of supply is consistent can we ensure that the quotations of each bidding manufacturer are based on the same basis, otherwise the commercial quotations will not be comparable.

(2) Business quotation analysis

The format of the bidding document stipulates a sub-item quotation table, which requires suppliers to quote for sub-item equipment. For oilfield export pumps, the itemized quotation includes ancillary equipment such as pump body, mechanical seal, flushing system, motor and safety valve. The main task of business bid evaluation is to analyze the manufacturers’ quotations and recommend the winning bidder based on the bid evaluation method. For price analysis, you can inquire with each sub-supplier for each sub-item quotation, compare the bidding manufacturer’s quotation with the market price, and verify whether the quotation is reasonable.

(3) Other business terms

Like the bidding and procurement of other equipment, the bid evaluation results of oilfield pumps will also be affected by many factors. The evaluation of other terms of the commercial tender document also needs to be carefully conducted. Review the supplier’s bidding documents to see if there are veto bid clauses and pay close attention to them; review key terms such as delivery date, payment terms, trade terms, etc. to see if they are consistent with the requirements of the bidding documents; for terms that are not clearly responded to, the supply must be requested dealer for clarification.

Professional requirements for purchasing personnel

The pump equipment procurement process is complex and requires many issues that need attention. It not only requires the procurement personnel to have high professional capabilities in bidding and procurement, but also requires the procurement personnel to have comprehensive and solid professional knowledge of pump equipment and have a certain level of professionalism. The specialization of pump equipment procurement personnel is mainly reflected in four aspects.

1. Basic knowledge and related standards

Basic knowledge is the fundamental starting point for solving problems. From getting started to becoming proficient, it requires an accumulation process. This process starts with having solid basic knowledge. For pump equipment, purchasing personnel should master the typical structure, working principle, head and efficiency, cavitation phenomenon, characteristic curve, working condition adjustment, etc. of the pump, and be able to distinguish the differences in production cycle and price of pumps with different parameters.

In addition, purchasing personnel should be familiar with relevant standards for pump equipment, especially international standards, such as API 610 “Centrifugal Pumps for Petroleum, Petrochemical and Natural Gas Industries”, API 674 “Rotary Positive Displacement Pumps – Reciprocating Pumps”, API 675 “Rotary Positive Displacement Pumps” -Metering Pumps”, API 676 “Rotary Positive Displacement Pumps – Rotor Pumps”, API 682 “Pump-Shaft Seal Systems for Centrifugal and Rotary Pumps”.

2. Materials and selection

Due to different media and working conditions, pumps used in oil and gas field surface engineering also have different requirements for pump materials. The materials of the pump include not only the materials of the flow-passing parts, but also auxiliary materials. For example, auxiliary sealing materials and rubber gaskets have requirements for applicable temperatures; the ambient temperature also affects the motor power. When the ambient temperature exceeds 40°C, the motor power will attenuate and other issues, which purchasers also need to pay attention to.

The selection of the pump equipment itself and ancillary equipment should be fully considered. For example, when confirming the self-priming height with the pump manufacturer, the pump foundation height and the center height of the pump inlet flange cannot be ignored; and if it is necessary to set up a buffer tank for buffering at the outlet of the reciprocating pump, it needs to be based on the flow allowed in the technical inquiry document. Determination of unevenness, etc.

3. Cross-professional knowledge

Pumps need to be used with motors, instruments and control systems. Pump purchasers need to have a certain understanding of motors, instruments and control systems, and be familiar with the corresponding sub-suppliers. Motors are generally produced by sub-suppliers. The motor’s energy efficiency level, explosion-proof requirements (flameproof or increased safety), bearing form, etc. must meet process requirements; instruments and control systems are used to monitor operating status and detect faults in a timely manner. Instruments and The control system is generally provided by the OEM, and professional requirements for instrumentation should be communicated to the OEM and sub-suppliers in a timely manner.

4. File management

According to the scope of work of the EPC project, the stage where pump equipment procurement documents are concentrated mainly includes purchase requisition documents, technical bid evaluation reports, contracts, completion documents, etc. Before receiving the purchase requisition document and issuing an inquiry to the bidder, the procurement personnel should verify the content and scope of the purchase requisition document to avoid the manufacturer being unable to quote due to incomplete specifications, data sheets, etc.; the technical bid evaluation report and contract shall be submitted by Project design and procurement personnel are prepared, making management difficult; the completion data is compiled by the pump manufacturer. Well-prepared completion data can bring great convenience to the subsequent construction, start-up, handover and other stages of the project.

Summarize

Pump equipment is widely used in oil and gas field surface engineering projects and is a key equipment. Different pump types are used in different projects, and the appropriate pump type needs to be selected based on the actual conditions of the project. Due to its complexity, pump equipment involves cross-professional knowledge. There are some aspects that require special attention during the bidding and procurement process of pumps. This article combines the author’s own actual project procurement experience to summarize and analyze the key points for purchasing pump equipment. In order to ensure procurement For the smooth progress of the work, it is necessary to focus on these points and minimize the occurrence of problems. At the same time, the professional requirements for pump equipment purchasers are summarized. On the basis of fully grasping the key points of each purchase, purchasers need to have a certain level of professionalism in order to improve the procurement management level of pump equipment for engineering projects.