Overview
In recent years, the textile and garment have always been one of important export sectors in Vietnam. In 2019 alone, the textile and garment industry exported $39 billion, accounting for nearly 15% of the country's total turnover. The government expects this industry to continue growing to maintain its position in the group of 3 countries and regions leading the export of textile and garment products in the world. By sub-sector, 70% are garment enterprises, 6% are yarns, 17% are textiles, 4% are dyeing and finishing companies, and 3% are auxiliary businesses. Among them, 85% of garment enterprises do CSC processing (cutting-sewing-cleaning) and 15% perform FOB (free on board).
With the Government having signed many trade agreements in recent years, textile enterprises have been facing great opportunities to develop and expand production. However, besides the advantages, joining trade agreements is also a challenge for businesses when the supply chain must ensure requirements for environmental protection and low greenhouse gas emissions. For example, the regulation on carbon labeling on textile products exported from Vietnam to the United States and Europe etc. requires importers to calculate the level of carbon emissions on the production technology chain corresponding to each textile product. This forces businesses to invest in modern production technology, cleaner production corresponding to and energy saving to increase the competitiveness of their products when exporting.
Current status and potential of energy saving in the textile industry
a) Structure of energy use in dyeing factory
The major resource consuming equipments in a dyeing plant are dyeing machines and stenters, both of which have high potential of opportunities for resource efficient use. The equipments with high power consumption mainly are stenter machines, boilers, oil heaters and wastewater treatment plants. The main water consuming areas include what in pretreatment, dyeing and washing processes. The main heat consuming areas/equipments are dye machines and stenters.
VECEA's survey results in 2017 - 2018 determined that the technology that businesses are using is still in low level. In textile dyeing enterprises, the rate of dyeing equipment over 17 years old (from 2000 and earlier) is 12.8%; equipment with age of less than 10 years is 34% and equipment with age of less than 7 years accounts for 36.2%. This status shows that there are still many old, outdated, low productivity, environmental pollution, low energy efficiency equipment being used in enterprises. Also according to this study, the dyeing - finishing process used by enterprises includes three types of processes: intermittent, semi-continuous (roll annealing) and continuous. In intermittent dyeing, equipment with dye-solution ratio[1] of 1:10-1:15 accounts for the majority of about 70%, equipment with low dye-solution ratio (from 1:2.5-1:8) accounts for 26%, and the remaining 14% are equipment with high dye-solution ratio (from 1:20 and above). With 70% of equipment with the dye-solution ratio of 1:10-1:15, the amount of feed water and wastewater of the dyeing and finishing process is still large, leading to the costs of treating feed water, chemicals, dyes, wastewater etc. Treatment fees of environmental protection for both feed water and wastewater are added to the product's cost, reducing the competitiveness of products, increasing pressure on businesses in terms of economy and environment, reducing the brand image of the business in the community.
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Structure of electricity consumption in a typical textile dyeing factory
(Source: IFC training material)
a. Structure of heat consumption in a typical textile dyeing factory (Source: IFC training material) b. Structure of water consumption in a typical textile factory (Source: IFC training material)
The main energy consumers in a typical garment factory are the sewing machine and the air compressor. The main energy consuming components include: Air Compressor, Sewing Machine, Iron, Lighting. The main areas of water consumption are the toilet and the kitchen.
b) Structure of energy use in a garment factory
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Structure of electricity consumption in a typical sportswear factory ----Structure of water consumption in a typical garment factory
(Source: IFC Training Materials)
To produce the same product value, Vietnamese enterprises must consume 1.5-1.7 times more energy than businesses in Thailand, China and Malaysia. According to calculations by experts, on average, the Vietnamese textile and garment industry loses 3 billion USD per year for energy costs in production. Electricity costs alone account for about 8-10% of total processing revenue. Water and electricity costs account for 14% of the cost of dyed fabric production. It is estimated that each year the textile and garment industry needs to use 5.8 trillion liters of water and 391 billion kWh for dyeing of fabrics.Published surveys of many units operating in the field of energy efficiency also show that there is still a lot of waste in water use in Vietnamese textile and garment enterprises. The level of waste is assessed to be up to 20-25%. Energy and water costs in textile enterprises are always high in the region, accounting for a significant proportion of the product cost structure.
A survey of VECEA in 2017 shows that, to produce 1 ton of textile products we consume about 200-300 m3 of water, 2500 – 3500 KWh of electricity and 12.5 tons of steam. Theoretically, it is possible to calculate the average for all types of equipment. At an average technology level, the producion of one ton of textile products consumes about 85-110m3 of water, 8 tons of steam, 2600 kWh of electricity. Thus, we can see that we still have a lot of potential to reduce the consumption of resource, raw materials and fuel in wet treatment of dyed textiles. From value aspect it can saved about 50-80 USD / 1 ton of product.
Generally, the potential to save energy and water in textile and garment enterprises in Vietnam is still very large.
General solutions to promote energy saving for the textile industry
The implementation of energy saving in the textile industry not only helps to reduce production costs, but also contributes to reducing environmental pollution, meeting carbon reduction requirements and complying with international commitments. In fact, there have been quite a lot of energy saving solutions implemented over the years, which can be surely replicated to apply to businesses in that field. For example, through a sustainability initiative in production called the Vietnam Improvement Program (VIP), IFC and global brands are promoting resource-saving production and the application of clean energy in the textile industry and footwear, focusing on factories in the strategic supply chains of these brands in Vietnam.
According to IFC training materials, VIP has proposed more than 800 resource efficient solutions, including solutions with low, medium and high investment costs. Low-cost options are resource-efficient plans that have an investment cost of less than $5,000; midle-cost solutions have an investment cost of $5,000 to $50,000 and high-cost solutions require an investment of more than $50,000.
The experience of the above Program also shows that up to 68% and 64% of water and energy savings come from 12% of high cost resource saving solutions, respectively. However, a resource-saving program can be initiated with low-cost resource-saving solutions that can also yield 9% and 23% energy and water savings, respectively.
Some specific energy saving solutions
a) Boiler and steam system
The textile dyeing sub-industry uses a large amount of heat from boilers or thermal oil furnaces for the dyeing process, wash, stretch forming (by stenter) or tumble dry. The fuel used to produce heat is biomass or coal. Normally, boilers and thermal oil furnaces are operated in load and no-load mode using a control system which based on pressure and temperature sensors.
To save energy, textile enterprises should prioritize using high-efficiency boilers with paying attention to choose a reasonable furnace capacity to avoid under-load conditions. In addition, it is nececessary to improve boiler/heater oil boiler efficiency by optimizing fuel combustion and combining with automatic/semi-automatic control system for furnace air supply and propulsion system, optimizing boiler blowdown water based on total dissolved solids (TDS) content of furnace water to improve boiler efficiency, improving condensate and expansion steam recovery, insulating hot surfaces of the heating system in order to minimize heat loss, replacing the old low efficiency boiler/heater oil furnace with a new high efficiency boiler, etc.
b) Lighting system
With a large space, the garment factory needs to consume a lot of electricity to ensure enough light for the entire workshop. Therefore, textile enterprises need to arrange offices and garment factories reasonably to get the most of natural light. In addition, businesses should use lamps with high lighting efficiency such as LED lights; at the same time, arrange reasonable light bulbs and switches to ensure lighting needs and save energy, apply local lighting to reduce the number of overhead lights, etc.
c) Sewing machines and specialized machines
The most energy consuming part in the sewing process is the sewing machines, so it is necessary to optimize the energy consumption and increase the productivity of the sewing machines. There are two types of sewing machines in use today: those using a traditional motor (also known as a clutch motor), and an electronic machine (machine using a servo motor).
Although the use of servo motors for traditional sewing machines is trending, many clutch motorized sewing machines still exist in textile factories. This is an opportunity for the factory to significantly improve the energy efficiency in its sewing lines.
Replacing mechanical sewing machines with electronic sewing machines improves not only labor productivity but also reduces energy consumption. If it is not possible to replace them with electronic sewing machines, businesses could consider replacing the traditional motor in a mechanical sewing machine with a servo motor or installing power savers for the mechanical machine. It can help to reduce motor power during no-load operation, which can save electricity. However, there is one thing to note, whether it is a mechanical machine or an electronic machine, businesses also need to choose machines with capacity and features suitable for the type of products of the factory.
d) Air compressor system
Energy saving measures can also be applied to the air compressor system of a textile enterprise. Accordingly, enterprises need to improve the efficient management of compressed air systems (CAS) by detecting and correcting frequent compressed air leaks, applying closed-loop distribution (ring systems) of compressed air systems, reduce the inlet air temperature of the air compressor, install a cluster control system for the air compressor, replace the low efficiency compressor with a high efficiency compressor, etc.
e) Water system
In addition to saving electricity, textile dyeing enterprises can also significantly save water through the recovery and reuse of water and heat from the high-temperature water source of dyeing machines. In addition, the dyeing plant may consider reusing the treated wastewater for the dyeing process through suitable filtration technologies such as R.O., etc.
For garment factories, simple solutions can be applied such as replacing conventional high-flow faucets with low-flow faucets for toilets and canteens; reusing treated wastewater from wastewater treatment plants, etc.
f) Usage of renewable energy
Applying solar hot water system is an energy-saving alternative to supply hot water for needs of textile factories. Experts estimate that 80% of hot water needs can be easily met by a solar hot water system without affecting fuel costs.
Textile enterprises that want to use clean solar energy can choose the solar power BLT solution, i.e. through the form of a roof-rental contract of factory with a service provider to install the solar power system and set an agreement to buy clean electricity generated from the system. With this solution, businesses do not need investment capital, do not need to maintain solar system, while using clean electricity at a reasonable price, meeting a criterion of green growth and sustainable development.
g) Optimizing energy consumption on the stenter
Arguably during the finishing process, on average the fabric will be processed 2.5 times on the stenter and it often delays production in the finish stage. The energy consumption of the stenters is a major factor related to the ecology of the stretch forming technology. Preliminary assessment shows that the energy consumption of energy-optimized form-tensioners (stenters) ranges from 3400-4500 kJ/kg of fabric. However, the energy consumption is highly dependent on the carried-out process.
The main heat energy consumed by the stenter is to supply the heat chamber. Depending on the design, the machine can be 6, 8 or 10 chambers. After the shaping/forming heat treatment, the new fabric structure can be stable to the use process such as cutting, sewing, washing. The heating chamber has an even distribution of hot air on both the top and bottom. Temperatures can go up to more than 2000 C and are uniform across all points of the fabric. Therefore, effectively mechanically dehydrating the fabric is the first step before heating in the heat chamber. In addition, the air/fabric ratio should be kept as low as possible to be technically and economically viable.
Technologies to reduce energy consumption of the stenter include: Installing a heat recovery system to utilize the hot air released from the stenter to preheat the incoming air; Good insulating thermal chambers; Applying automatic adjusting and control system for temperature, air flow, fabric humidity; Applying direct combustion technology through burners in the heating chamber instead of using oil to carry heat from the central furnace system.
h) Optimizing the efficiency of the dyeing process
The application of biological-based chemicals in the dyeing process to reduce COD and BOD content in wastewater is a solution that many dyeing plants are interested in. Some typical solutions are popularly applied such as: Apply biological cleaning method in the pretreatment process to optimize the cotton fabric dyeing process; Replacing alkaline detergents with acid based detergents for polyester fabrics; Optimizing the temperature of the dyeing process, etc. These solutions are all non-investment solutions but help the plant significantly reduce water and energy consumption, reduce the pollutant load in wastewater and increase energy productivity, increase quality and reduce the number of defective products in one dyeing batch.
In addition to the above-mentioned solutions without investment costs, it is necessary to replace the old, outdated technology (having the high dye-solution ratio) of dyeing machines, especially high-pressure dyeing machines (that are currently using a ratio of 1: 8 – 10) with the new technology dyeing machines (having the ratio of 1: 3- 4). It is a measure to help dyeing factories significantly save resource consumption, reduce emissions of environmental pollutants. It is also a premise for the application of dyeing techniques to reuse treated wastewater for dyeing process. Besides, new technologies such as cold dyeing (roll dyeing), continuous dyeing combined with a caustic soda recovery system are also being interested and applied in some dyeing factories recently.
Conclusion
Besides the above technical solutions that can be used in enterprises, to promote the application of energy saving solutions in the textile industry, the role of state agencies is also very important. The State needs to determine the priority technology or the technology that should be prohibited or restricted in investment. For example, investment is prohibited for: Technologies that fails to ensure occupational safety and hygiene as prescribed by law; Technologies to create hazardous waste for humans, flora and fauna ecosystems and the environment; Technologies are outdated, which consume a lot of water, energy, chemicals and materials, and have the economic and technical indicators of the production process much worse than those available in the country. Restrict investment for: Technology using old machinery and equipment or technology to create old-generation products that do not save energy; Technology to create products generates waste in excess of the national technical regulations on the environment and requires an accompanying treatment system. Prioritize investment in new, modern, energy-saving and environment-friendly technologies.
MSc. Mai Van Huyen, GreenDC
& Vietnam Energy Conservation and Energy Efficiency Association
1) Research and prioritize the development of clean, environmentally friendly technologies in the Textile - Dyeing and Paper - Pulp industries (Study research in the Ministry of Industry and Trade level - 2018)
2) Vietnam Resource Efficiency Improvement Program – IFC (Training Material)
[1] Dye-solution ratio: typical solution ratio (weave weight (kg)/volume dye solution (l)
