Kenichi MORI*
Bunshi ONO**
*
Ebara Vietnam Pump Company Limited
**
Fluid Machinery & Systems Company, Business Development Division,
This paper introduces the pumps, facilities and projects we delivered for the Da Nang Water Supply Joint Stock Company (DAWACO) in Vietnam, which were completed in 2017. This project is based on the Joint Crediting Mechanism (JCM) promoted by the government of Japan. The pumps delivered were, at the time, the latest model developed by Ebara Corporation specifically for high efficiency and were the first delivery of such pumps to Vietnam. In Vietnam, which is experiencing rapid economic growth, environmental protection is being recognized as an important issue. This recognition inspired the project's objective of replacing the existing pumps with high-efficiency pumps model CWX to help reduce greenhouse gas emissions. In implementing the project, Ebara Vietnam Pump Company Limited (EVPC) was able to take the lead in expediting all practical work, thanks to its characteristic system of locating a project department, a design department, and a production plant all in one place.
Keywords: Vietnam Da Nang City, Da Nang water supply joint stock company, Ebara Vietnam Pump Company Limited, Joint Crediting Mechanism, Distribution Pump, Intake Pump, CO2 emission factor, Greenhouse Gas
Da Nang City, the fourth largest city in Vietnam, is one of the five centrally-controlled municipalities of the country. In addition, as shown in Figure 1, Da Nang is also the city in Vietnam at the eastern end of the East-West Economic Corridor connecting Myanmar, Thailand, and Laos on the Indochina Peninsula and is drawing attention as the economic center of the south-central region. The city covers an area of 1 283 km2 with a population of 1 134 310 (announced by the Da Nang Statistics Bureau on April 1, 2019) and is promoting the development of an environmentally friendly city with the aim of invigorating tourism, which is one of its main industries. In association with its industrial agglomeration, rapid population increase, and expansion of tourism development stemming from its economic growth, the importance of environmental considerations is also being recognized.
Vietnam has been making remarkable economic growth (economic growth rate of 6% to 7% per year before the coronavirus pandemic), and its energy consumption has also been on the increase. Its electricity rate is approximately 10 yen/kWh, which is high considering the level of prices, so the importance of higher energy efficiency is increasing.
Figure 1 East-West Economic Corridor and Da Nang City
The Japanese Government is promoting the Joint Crediting Mechanism (JCM)*1, which quantitatively evaluates contributions to matters including the reduction of greenhouse gas (GHG) emissions in overseas countries through the provision of advanced low carbon technologies, infrastructure, and products, and is utilizing the outcomes thereof to achieve Japan's reduction goals.
As a technical collaboration measure between Vietnam and Japan, Da Nang City and Yokohama City signed the “Memorandum of Understanding on Technical Cooperation for Sustainable Urban Development” in 2013, and have been committed to resolving urban issues of various types through inter-city collaboration. In 2015, the “JCM Project Formulation Feasibility Study Contracted Program for Realizing a Low Carbon Society in Asia” was conducted under the structure of inter-city collaboration between Da Nang City and Yokohama City. This study program was the trigger for the project to be introduced here.
*1
Facility subsidy project of the Joint Crediting Mechanism (JCM) financial support project: Subsidy project carried out by the Ministry of the Environment. In this project, programs for reducing greenhouse gas emissions in developing countries by utilizing outstanding low carbon technologies and other methods, and through measurement, reporting, and verification (MRV), are conducted. With the aim of adding the calculated reduced emissions to Japan’s reduced emissions under the JCM, a facility subsidy will be granted to business operators (international consortiums), with one-half of the initial investment cost as its upper limit.
Ebara Vietnam Pump Company Limited (hereinafter referred to as “EVPC”) was established as a joint venture between Ebara Corporation (hereinafter referred to as “Ebara”) and a local pump manufacturer in Hai Duong Province in northern Vietnam in 1995, and then became a wholly-owned subsidiary of Ebara in 2011. In 2016, a new medium-/large-scale pump manufacturing factory equipped with casting facilities and can manufacturing facilities was established in the Lai Cach Industrial Park in Hai Duong Province. EVPC operates the EVPC Hanoi Branch, which is the main sales base in Vietnam, in addition to the pump manufacturing factory. The Hanoi Branch has not only a sales department but also a system engineering department that undertakes the planning and design of entire pump stations.
On the occasion of the release of the high-efficiency model CWX pump newly developed by Ebara in 2016, EVPC’s sales department introduced the new model CWX pump to the Da Nang Water Supply Joint Stock Company (hereinafter referred to as “DAWACO”) as a part of sales expansion activities. Meanwhile, EVPC’s system engineering department lent its cooperation to the “JCM Project Formulation Feasibility Study Contracted Program for Realizing a Low Carbon Society in Asia” mentioned earlier, and conducted a field survey and technical review with a Japanese survey team.
In light of the results of this survey, Yokohama Water Co., Ltd.*2 commenced a full-scale project feasibility study for introducing the high-efficiency pump to the Cau Do Water Plant under the charge of DAWACO (Figures 2 and 3). In 2016, Yokohama Water and DAWACO formed an international consortium (Figure 4) and applied for the Ministry of the Environment’s JCM facility support project, “Introduction of high-efficiency pumps to Da Nang Water Supply Joint Stock Company.” This project was accepted, and then was completed in 2017. EVPC’s initiatives in the project are explained below.
*2
Figure 2 Cau Do Water Plant
Figure 3 External view of Cau Do Water Plant
Figure 4 Scheme of the “Introduction of high-efficiency pumps to Da Nang Water Supply Joint Stock Company” project
The official name of this “Introduction of high-efficiency pumps to Da Nang Water Supply Joint Stock Company” project is "Replace 09 units of pump for the Cau Do water plant with high efficiency water pumps (the JCM model project in Da Nang).” The project aims to contribute to reducing greenhouse gas (GHG) emissions by upgrading the existing pumps of two pump facilities for water intake and water distribution in the Cau Do Water Plant, a water treatment plant owned by DAWACO, to high-efficiency units.
The details of the water intake and water distribution pumps, which are the main equipment of this project, are indicated below. The station (area) where the water intake pumps are installed is referred to as Level-1, and the station where the water distribution pumps are installed is referred to as Level-2.
Water intake pumps (Level-1): 450 × 350 model CWX, 3 units
Water distribution pumps (Level-2): 500 × 350 model CWX, 6 units
A diagram of the configuration of all facilities and the flowchart for measurement at the Cau Do Water Plant are shown in Figure 5. In this project, in order to quantify the results of the upgrade according to the JCM scheme as the effectiveness of reducing CO2 emissions, we are planning to observe the operational state of the facilities from August 30, 2017 when the delivery of equipment was completed, until 2035. To this end, a system designed to collect data on flow rate, pressure, and power consumption is being used.
Figure 5 Data collection system configuration diagram of the Cau Do Water Plant
The planned effects of reducing power consumption and CO2 emissions after the pump upgrades are as indicated below.
Annual reduction amount of CO2 emissions: 748 [tCO2/year]
= (Reference CO2 Emissions) - (Project CO2 Emissions)
= ((Reference Power Consumption) - (Project Power Consumption)) × [MWh/year] Emission Factor [tCO2/year]
The amount of reduction for each facility is as follows:
[Water intake pump station Level-1]
104 [tCO2/year] = (994.5 - 881.4) [MWh/year] × 0.919 [tCO2/MWh]
[Water distribution pump station Level-2]
644 [tCO2/year] = (5 941.9 - 5241.3) [MWh/year] × 0.919 [tCO2/MWh]
We conducted a survey of the existing facilities in order to identify the effects of introducing the high-efficiency pumps. The results of the survey of each pump station at Level-1 and Level-2 are indicated below.
1) Level-1 water intake pump station
Number of pumps installed: Three units (two units normally operated in parallel)
Flow rate: 1 000 m3/h (48 000 m3/day when two units were operated)
Total head: 19 m
Rated running speed: 990 rpm
Rated output of pumps: 110 kW
Efficiency when two pumps were operated: 50.5 %
In the water intake pump station, the effects were identified using equipment displays and operation records since there was no detailed technical material on the existing equipment. The equipment had deteriorated with age, and the power consumption corresponding to the flow rate was 0.133 kWh/m3.
In addition to the abovementioned survey, EVPC conducted a field survey of the following in order to implement the upgrading plan:
・Water level on the water intake side
・Piping renovation plan
・Investigation of the process piping resistance from the piping geometry
・Pump facility plan by identifying actual operation points
In the catchment basin of this water treatment plant, the water level of the river varies over several meters between the dry and rainy seasons, so it was necessary to set a planned water level that can ensure the stable operation of the facilities throughout the year. We also planned the pump operation point settings to enable them to demonstrate their maximum efficiency within the variation range of the operation points incident to changes in the actual head. Furthermore, we planned renovations to the main piping close to the connections of the pump facilities because matters including the arrangements of the main piping facilities would be changed in association with the upgrading of the pump facilities.
2) Level-2 water distribution pump station
Number of pumps installed: Six units
Flow rate: 2 400 m3/h (170 000 m3/day when five units were operated in parallel)
Total head: 42 m
NPSH Req:12 m
Rated running speed: 1 470 rpm
Rated output of pumps: 450 kW
Four pumps are equipped with inverters (operated at 48 Hz).
Since the existing pumps were installed in 2008, they produced unusual vibrations and noise during operation, and the sliding portions were seriously worn. The power consumption was 0.188 kWh/m3 at the rated total head.
Figure 6 shows the changes in the operation points during one day, with the pressure and flow rate at each time. Figure 7 shows the operation points of each operation pattern with multiple units in operation. Based on this data, it is necessary to implement a flexible operation pattern in response to time periods or variations in water demand in order to optimize operation.
Figure 6 Operation record over one day at Level-2
Figure 7 Operation record for respective operation patterns at Level-2
Summarized data based on the measurement results of the power consumption of each of the existing pump facilities is shown in Tables 1 and 2.
| Number of pumps operated (units) | Power consumption (kWh/m3) | Equipment efficiency (%) |
| 2 | 0.133 | 50.5 |
| Number of pumps operated(units/units)*3 | Power consumption (kWh/m3) | Equipment efficiency (%) |
| 5/3 | 0.178 to 0.186 | 61.4 |
| 5/4 | 0.176 | 64.3 |
| 4/2 | 0.151 | 70.1 |
| 4/4 | 0.152 | 66 |
| 3/3 | 0.119 | 62.5 |
| 3/2 | 0.158 | 64.6 |
Based on the results of the survey of the existing facilities, the operation point plans were revised. An overview of the planned renovations to the facilities is indicated below.
Number of pumps installed: Three units (two units normally operated in parallel)
Flow rate: 1 200 m3/h (57 600 m3/day when two units were operated)
Total head: 12 m
Rated running speed: 990 rpm
Rated output of pumps: 55 kW
Efficiency when two pumps were operated: 86%
Newly installed pumps: 450 × 350 model CWX manufactured by EVPC
With these renovations, the corresponding flow rate of the facility capacity was enhanced by approximately 20%. Also, the power consumption evaluated from the facility efficiency was reduced by approximately 20% from the power consumption of the existing facility shown in Table 1.
The planned performance curves of the pumps after the renovations are shown in Figure 8. We planned to achieve an optimal operation point with an efficiency of approximately 86% after the pump renovations. The operation point of the existing pumps is also indicated by a “♢” symbol in Figure 8, and at this point, the pumps were operated with a poor efficiency of approximately 65%. For the pumps considered at the time of planning, the high-efficiency model CWX pump newly developed by Ebara was adopted. The model CWX pump has approximately 3% to 5% higher efficiency than EVPC’s past pump models and is expected to significantly reduce power consumption in combination with the abovementioned operation plan.
Figure 8 Pump performance curves at Level-1 after renovations
Number of pumps installed: Six units (including one spare unit)
Flow rate: 2 400 m3/h (230 000 m3/day when five units were operated)
Total head: 52 m
Rated running speed: 990 rpm
Rated output of pumps: 420 kW
Efficiency when two pumps were operated: 89%
Newly installed pumps: 500 × 350 model CWDM manufactured by EVPC
We conducted the same survey at the water distribution pump facility and succeeded in reducing power consumption by 15% or more compared to the operational state of the existing facility shown in Table 2. As described earlier, it is assumed that the pumps will be operated at the operation point by changing the number of units in response to the demand and by implementing speed control using inverters. As an example, an operation point plan for operating five units in parallel is shown in Figure 9.
Figure 9 Operation plan for parallel operation at Level-2
The newly developed high-efficiency model CW pump has been adopted also for the water distribution station Level-2, just as at the water intake station Level-1. The planned performance curves of the pumps at Level-2 after the renovations are shown in Figure 10.
Figure 10 Pump performance curves at Level-1 after renovations
Table 3 shows a comparison of the facility appearance and performance of water intake pump station Level-1 before and after the renovations, and Table 4 shows that of water distribution pump station Level-2. The annual power consumption was reduced by 228 665 [kWh/year] at Level-1 and by 2 019 701 [kWh/year] at Level-2.
In this project, we studied and proposed an optimal operation method aligning with demand, to enable the pumps to continue optimal operation even after delivery.
The changes in demand during one day at the water distribution pump facility which were checked by field surveys are shown for 2015 in Figure 15 and for 2017 in Figure 16. Although the demand at the time of introduction of the renovated facilities is planned to be relatively stable as compared to 2015, it has been confirmed that during operation over one day, the demand changes between a minimum of approximately 42 m to a maximum of approximately 52 m.
Figure 15 Demand over one day for the water distribution pump facility in 2015
Figure 16 Demand over one day for the water distribution pump facility after renovations in 2017
To reproduce this operation plan, we recommended the operation plans indicated below for the delivery of facilities in this project. We planned the operation patterns noted as Case-1 to Case-3 in accordance with the demands shown in the 2017 operation plan (Figure 16) to ensure operation with high efficiency.
Case-1 Operation points of the water distribution pump station (1)
Operation method: Operation of five units at 100% running speed
Pump operation point: Total head: 52 m, flow rate: 12 000 m3/h
Figure 17 shows the operation point plan.
Figure 17 Operation point plan for the water distribution pump station (1)
Case-2 Operation points of the water distribution pump station (2)
Operation method: Operation of four units at 93% running speed
Pump operation point: Total head: 42 m, flow rate: 10 000 m3/h
Figure 18 shows the operation points.
Figure 18 Operation point plan for the water distribution pump station (2)
Case-3 Operation points of the water distribution pump station (3)
Operation method: Operation of four units at 100% running speed
Pump operation point: Total head: 47 m, flow rate: 11 000 m3/h
Figure 19 shows the operation point plan.
Figure 19 Operation point plan for the water distribution pump station (3)
As mentioned earlier, the measurement of this facility is still in progress in order to monitor the effect of reducing its power consumption. We will further continue activities in Vietnam with the expectation that the verification results will be recognized by DAWACO and relevant authorities in Vietnam and the parties related to Japan’s JCM scheme, so that further opportunities can be created.
The basic design of the high-efficiency model CW pump (double-suction horizontal pump) delivered in this project was completed in 2015, and it has been put on the market since 2016. Figure 20 shows the appearance of the pump.
Figure 20 Model CW/CC/CN double-suction single-stage centrifugal pump
The standardization of this model CW was implemented through the cooperation of the development department of Ebara’s Futtsu Plant and the engineering department of EVPC from the beginning of development, on the assumption that EVPC would manufacture it. At present, the number of units of this model delivered even in Japan is on the increase, with many of them manufactured by EVPC.
In this project, it was necessary to share the significance of the contents of its plan with the parties in Japan related to the promotion of the JCM project as well as with facility owner DAWACO, and to gain their understanding of the effects that the project would bring about. This time, we successfully contributed to improvements in areas such as reducing greenhouse gas (GHG) emissions and energy consumption, by upgrading to the high-efficiency model CWX pump. This was an excellent case for demonstrating “1. Contribute to the creation of a sustainable society,” one of the five key issues that the Ebara Group is endeavoring to resolve and make improvements in as we look toward 2030. Another aspect of this project was that it was realized by the full-scale efforts of EVPC, from field surveys to construction work and the manufacture of the main pumps together with whole process engineering. Behind this project lies the devotion of the staff of each department in Ebara’s Fluid Machinery & Systems Business, who established a base in Vietnam in the latter half of the 1990s and has developed its staff in Vietnam over many years.
We would like to express our deepest gratitude to Yokohama City, Yokohama Water, and all parties concerned for their guidance and cooperation in this project.