Production Process And Technologies

The bulk of the environmental impact from glass production is caused by emissions from melting activities during the float glass production process. At AGC Glass Asia Pacific, we are committed to reducing the environmental impact of our production processes and technologies by constantly improving and innovating technologies that contribute to better environmental performance. These efforts are aligned with our environmental target to reduce our greenhouse gas emissions to reach our 2030 target.

1. Conventional Float Production Process

The float glass production process has one of the largest environmental impacts. To better understand the environmental aspects, we must first define the float glass production process.

1.1. The raw materials

The basic raw materials used in flat glass production are:

Glass-forming materials: silica sand and glass cullet
Intermediate and modifying materials such as sodium carbonate, dolomite, limestone, sodium sulphate, feldspar and blast furnace slag
Colouring and coating agents such as iron oxide and other metallic compounds.

1.2. The float process

During float glass production, the raw materials are mixed together and melted in the furnace to form molten glass which is then poured into a bath of molten tin. The furnace uses air and natural gas combustion to melt the raw materials. As the glass cools and solidifies, it floats in the tin bath forming a glass ribbon. At this point, coatings can be applied on the glass at the end or just after the tin bath. The glass ribbon subsequently passes on to a zone for annealing where it cools down gradually while being carried on rollers and to be cut into sheets.

1.3. Further processing

After the glass is cooled down, it can be processed into other products. For example:

Glass for mirrors can be painted and silvered
Glass for architectural purposes (buildings, furniture etc.) can be coated, made into double glazing units, tempered, enamelled, painted, laminated, etched, etc.

2. Reducing Greenhouse Gas emissions through glass melting process innovation

2.1. Indonesia: PT Asahimas Flat Glass Tbk

From 2015 to 2019, AGC Glass Asia Pacific conducted and completed a major plant relocation from Jakarta to Cikampek. This new plant was upgraded with many state-of-the-art technologies. As part of these upgrades, special refractories and furnace designs have been applied to the "Regenerator" which have a significant positive impact on the energy efficiency. This enabled enhanced heat retention performance, improved durability and long-term use.

We expect to reduce CO₂ emissions by 13,000 tonnes per year with this new technology and equipment.

2.2. Thailand: AGC Flat Glass (Thailand)

From 2020 to 2021, the float furnace at AGC Flat Glass Thailand Samut Prakan plant underwent cold repair where glass production and flow of fuel was stopped to cool down the furnace completely. The production line was renovated and upgraded with the most advanced energy and efficient furnace technology from AGC Glass Europe. As a result, there is significant improvement to the furnace's combustion efficiency and productivity. It was the first plant to do this in the Asia Pacific region.
 
We expect to reduce CO₂ emissions by 10,000 tonnes per year with this new technology and equipment.

2.3. Next measure for Greenhouse Gas Reduction in Asia Pacific

Full oxygen combustion technology 

This technology realised much higher combustion efficiency than a conventional furnace because they do not heat excess nitrogen. Air contains around 21% oxygen and 79% nitrogen. The nitrogen is not only useless in the combustion process but at high temperatures produces nitrogen oxides (NO_x) which is a greenhouse gas. Thus, using pure oxygen instead of air helps to reduce the energy needed for the combustion as it is no longer necessary to heat up the nitrogen and prevents the formation of NO_x.

AGC is progressively applying oxygen combustion to flat glass production furnaces around the world, starting with the Yokohama Technical Center mould plate line.
 
In addition to this new oxygen combustion technology, AGC Architectural Glass Asia Pacific is considering introducing hot oxygen combustion, which has already proven effectiveness in AGC Glass Europe.

We are also working on developing the technology for ammonia combustion, allowing us to transition to carbon-free fuels and produce glass with far lower greenhouse gas emissions.

3. Energy Efficient Technologies in Asia

AGC Group highlighted the "promotion of sustainability management" as one of the priority issues in its medium-term management plan AGC plus-2023 and has set a goal of achieving net zero carbon net from its own business activities by 2050. We have taken various measures to reduce GHG emissions in the glass manufacturing process, including the introduction of an oxygen combustion method with high melting efficiency, a fuel conversion from heavy oil to natural gas, and the introduction of an electric booster for melting. We will continue working towards the realisation of a sustainable global environment by reducing GHG emissions and supplying products and technologies that contribute to energy efficiency.

3.1. New Solutions to Reduce Carbon Footprint

Organic Rankine Cycle (ORC) module

AGC Flat Glass Thailand's Samut Prakan plant is slated to be installed with an Organic Rankine Cycle (ORC) power generation system in 2023 with the aim of reducing indirect CO₂ emissions and also lowering electricity costs. Flue gas is gas that is released during combustion of fuel. In glass production, it is produced from the glass melting furnace. The system generates power by taking the waste heat from this flue gas and converting it into electricity. This works via an Organic Rankine Cycle (ORC) module that uses an organic oil with a low boiling point. The system is expected to generate 14 GWh of electricity per year by extracting waste heat from the flue gas produced by glass melting furnaces and converting it into electricity, increasing energy efficiency.

Electricity generation by photovoltaic panels

AGC Architectural Glass Asia Pacific plans to install photovoltaic (PV) panels to generate green power within the plant. This will be installed in AGC Flat Glass Thailand Chonburi plant and also several production sites in Indonesia in 2023. A total output of 14 GWh of photovoltaic capacity will be created which will help reduce indirect emissions from energy consumption.

Sustainability