HyGear BV

As the focus is shifting towards reduction of harmful emissions, industries are constantly searching for alternative ways to reduce the environmental impact of their processes. At the same time, companies in the glass industry are continuously seeking ways to optimize the glass production process, improving the glass quality, and reducing costs.

As a gas supplier, HyGear made its entry into the flat glass industry with its small-scale on-site hydrogen generation systems that fit the requirements in terms of gas purity, reliability in gas flow, and significant cost reduction. The company has also identified the needs of glass companies to use more protective gases in order to improve the quality of their end product. Currently, all these gases are vented into the environment, and largely, within the facility of the glass plant.

The increasing desire to reduce environmental impact therefore conflicts with the objective to reduce costs and improve product quality. This was the starting point for the development of the Hy.RECmix. This technology has the ability to recover, clean, and recycle the vented gases from the tin bath and feed them back into the process. By using this method, the amount of fresh gases that is required for the process reduces, thus leading to lower expenses and less venting. This entails in the reduction of harmful emission without jeopardising the product quality.

Advantages

HyGear is not the first company that designed gas recycling systems. The reason for the limited market penetration of the formerly launched systems is the low internal rate of return caused by high capital investment and high energy consumption. Both aspects are due to the fact that the spent gases are only available at low pressure and most of the common upgrading methods require large pressure differentials. The Hy.RECmix is designed on innovative low-pressure upgrading technologies and therefore, consumes the lowest possible electricity, and lowest possible maintenance expenses.

Most importantly, the Hy.RECmix does not interfere with the glass production process. Connecting the Hy.REC to the float line is not limited to the period when a cold or hot repair has to be carried out; it can be done while the float line is operating under its normal conditions.

Reduction of environmental impact

The development of the Hy.RECmix is to recover the gas mixtures from the tin bath in float glass production and to reuse the gas within the process. In the current production process, significant amounts of hydrogen and nitrogen gas mixture, including pollutants, are vented and left unutilized.

This technology has proven to be an effective method for cost reduction as the amount of fresh gases feed will decrease and the carbon footprint of the whole process will decrease as well.  The following figure shows the reduction of CO2 and dust emissions associated to the supply chain of nitrogen and hydrogen.

Working principle

Extraction of the entire mixture of hydrogen and nitrogen that can be done from the hot-end of the tin bath. Depending on the desired venting rate, this could go up to 700 Nm3 per hour on a single Hy.RECmix system.

 There are three stages in the process of gas recovery by the system.

• Firstly, the dust removal stage uses cooling and mechanical separation techniques to remove tin-oxide from the recycle gas flow. Tin can be recovered from the captured dust and used again in the float line.
• Next, the sulfide and oxygen removal stage uses physical and chemical low pressure separation techniques for desulphurization and deoxidation.
• And finally, the post treatment stage concerns the drying of the gas mixture and the further purification up to the purity and dew point required to be fed back into the process 

The advanced gas cleaning system, Hy.REC will feed the recovered gas through HyGear’s low pressure supply system to each of the float line bays separately ensuring low pressure drop and continuously gas supply. Through the company’s highly reliable feeding system, the float glass plant operator has the ability to separately configure the gas composition in each bay of the float line allowing the controller to reduce the hydrogen required in different parts of the tin bath.

The status of technology

The Hy.RECmix technology was developed in close cooperation with Saint Gobain. Over the past years, modules for cleaning different components were tested at HyGear as well as Saint Gobain’s float line in Herzhogenrath Germany. These tests have led to an integrated system that is currently installed in Saint Gobain’s float line in Porz Germany, where it is deployed to recover a maximum of 700 Nm3 per hour of mixed gas from the tin bath, clean it and feed it back into the process.

More information

The HyRECmix offers a series of technologies that are combined in an innovative way to lower capital expenses (CAPEX) and operational expenses (OPEX). The operation of the system is fully automated and the quality of the gas produced is continuously monitored by the system’s programmable logic controller (PLC).

The Hy.RECmix is a standardized system that fits every float line in the world but can be tailored to specific requirements of different float lines related to the number and location of injection points and variations in gas compositions over the tin bath. The systems are housed within a 40ft container or can be skid mounted to match space restrictions in specific situations. Installation, integration, and commissioning at the site can be accomplished in four weeks.

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