Natural gas is essential in brick production Steenfabriek Huissenswaard in Angeren churns out 75 million bricks annually
The Netherlands are a country of brick buildings. Each year, roughly 800 million bricks flow into construction projects to build apartment and office buildings or they are used as paving stones for gardens, roads or city squares. The average single-family home alone requires about 5,000 to 10,000 bricks. Most people don't realize that making bricks would be almost impossible without natural gas. TCKI, the Dutch Center for Ceramic Building Materials Industry, helps brick manufacturers nationwide improve their manufacturing processes and maximize their gas usage efficiency. One of these manufacturers is Steenfabriek Huissenswaard in Angeren in the eastern part of the country.
In the Netherlands, around 800 million bricks are used in construction each year.
5,000 to 10,000 bricks are required for an average Dutch house.
Brick production would scarcely be possible without natural gas.
TCKI, the Dutch Center for the Ceramics Building Materials Industry
In Velp, a small town near Arnhem on the German-Dutch border, TCKI uses state-of-the-art equipment in its labs to test the properties of roofing tiles or bricks. “A brick consists of up to ten different materials. Here in Velp we analyze the properties of these materials,such as their frost and moisture resistance for roughly 60 manufacturers of bricks and roofing tiles,
as well as for the fine ceramics industry,” says Hans Marks, the deputy director of TCKI. The Dutch Center for the Ceramics Building Materials Industry advises its clients in all matters of process control such as gas consumption. It also makes recommendations regarding raw materials and temperature adjustments when drying or firing bricks.
Kiln on wheels
Since customers in the building materials industry are generally conservative, they tend to initially reject or at least be skeptical regarding ideas for changes in the respective manufacturing processes. In response, the TCKI researcher designed a drying system on wheels. They drive it to brick manufacturers and analyze their production methods on-site. “We look at the ventilation, the temperature and humidity profiles, as well as the energy consumption. Based on the measurements we then propose how the client can reduce his production costs, for example by drying the bricks in a way that requires less heat,” says Marks.
“Making changes always requires a little courage, however.” With the mobile drying system, our employees demonstrate to the client whether the production method works with the new parameters and what changes they would have to make to their existing plant. Marks: “This allows us to constantly improve the processes in our industry and elevate it to a higher level. As a result, we have state-of-the-art companies in the Netherlands that are able to compete in the European market.” One of these – and a client of TCKI – is Steenfabriek Huissenswaard in Angeren in the eastern part of the country.
100,000 cubic meters of clay become 75 million bricks annually
The production is running at full speed at Steenfabriek Huissenswaard. One thing that immediately stands out in the Angeren plant is the giant tunnel kiln with 14 rows of gas burners, each with 25 jets. But before the bricks can be fired, the clay has to go through many processing stages. After being “harvested” in the river basin, it is taken to the clay storage area and blended to even out natural differences and ensure consistent quality. From here, the clay is shipped to the factory and filled into so-called box feeders.
Using rollers, the clay is broken down into finer and finer parts. Next, it is mixed, kneaded to form a moldable paste, and pressed into bricks. This does not require a lot of staff. “The entire process is fully automated and computer-controlled,” explains Harm Janssen, managing director of production at Steenfabriek Huissenswaard. Next, the molding boxes in the press are filled with clay. “The press has a capacity of 30,000 bricks per hour, enough for five single-family homes,” says Janssen.
From room temperature to 1,000 degrees Celsius
In the kiln, the bricks are dried for 48 hours at a temperature no higher than 70 degrees Celsius (158 degrees Fahrenheit) while giant fans move huge amounts of air. Some of the hot air is extracted from the tunnel kiln, some comes from the factory’s own cogeneration plant. “Each of the ten drying chambers holds 53,856 bricks. Each week we empty and refill 28 drying chambers,” says Janssen. Via the stacker, which stacks the bricks and combines them into kiln car packages, the bricks enter the giant tunnel kiln, where they are fired with natural gas.
Depending on the product and the type of clay being used, the temperature reaches between 1,070 and 1250 degrees Celsius (1958 and 2,282 degrees Fahrenheit) in the oven, which is 6.1 meters wide and xx meters long. Natural gas also plays a role in the packaging process. As soon as a pallet has been filled, it is foil-wrapped in a gas-fired packaging facility. When hot air produced in this facility is blown over the pallet, the foil shrinks and forms a tight seal over the bricks. Thus held securely in place, the bricks can then be safely transported to the stacking yard. The 30-hectare area has room for 50 million bricks.
Natural gas is the ideal fuel for this process, because it is flexible, easy to control, and easy to transport. “For brickyards, natural gas is and will continue to be the best energy source,” says Hans Marks. In addition, reduction-fired or oxidized bricks could only be produced with natural gas. “By slightly adjusting the firing process or the amount of gas you can make reduction-fired bricks with interesting color gradations, which are very popular in the Dutch construction industry.”
10 million cubic meters of natural gas per year
The gas consumption of Steenfabriek Huissenswaard is considerable: it burns ten million cubic meters of natural gas per year. It is therefore no wonder that energy accounts for one-third of the manufacturing costs. Since the oil crisis of 1974, TCKI has been advising companies on how to reduce their energy consumption and improve their production processes. The Center additionally provides support for the steady reduction of energy consumption in this branch of industry and also prepares energy savings plans on behalf of the Netherlands Enterprise Agency (RVO). Thanks to the advice provided by TCKI, Steenfabriek Huissenswaard has been able to cut its energy consumption in half since 1980. The company also benefits from the benefits provided by TCKI's pooled energy procurement service for many market players.
“Natural gas is the most important energy source in brick production.” Interview with Hans Marks, deputy director of TCKI, and Harm Janssen, managing director of production at Steenfabriek Huissenswaard
Why do brickyards use natural gas?
Hans Marks: Natural gas is ideal for the production of bricks. It is also cheaper and more environmentally friendly than other energy sources. One of its greatest benefits is the ease and accuracy with which you can control it. With flow sensors we can control the supply of natural gas throughout the production process. If you were using coal to heat the kiln, you would wind up with 25 percent ash in air of the plant. It would also release sulfur, which discolors the final product. You’d never know how your product would react. Oil has the drawback that it is viscous and reacts sensitively to irregular heating, which leads to quality variations. Oil is also a fire hazard and contaminates the burners. Unlike other energy sources, natural gas also does not pose any transportation problems. For brickyards, natural gas is and will continue to be the best energy source.
What volumes are we talking about?
Hans Marks: We are talking about 100 to 200 million cubic meters, depending on the year and the number of participants. We currently serve about 20 companies. Suppliers like working with us, because our user characteristics are fairly constant. There are few peaks and valleys, because we use natural gas for both drying and firing. Since these processes run day and night, the gas consumption is relatively stable at all times.
TCKI handles the energy purchases for participating companies. Can you explain this in more detail?
Hans Marks: We began pooling the energy procurement for participating companies when the market was liberalized in 2000. Since prices are very low at the moment we have already entered into supply deals through 2020. Each year we look for the best offer by putting the business up for bids. We don't just look at the price, but other terms as well. Ancillary costs, for example for storage, as well as flexibility and risk mitigation are also important. After all, you never know in advance how much natural gas you will actually need over the long term. Only suppliers who are willing to carry this risk are of interest to us.
TCKI has been an independent research institute, knowledge center and consultation bureau for mineral resources and building materials produced from them for more than 60 years. TCKI provides a wide range of expert knowledge in the energy-intensive production of ceramic building materials such as bricks and roofing tiles. TCKI conducts process measurements for manufacturers and buyers of ceramic building materials, rates natural resources and products, and provides advices on cost savings as well as quality and quantity improvements. Since the liberalization of the energy market, TCKI has also functioned as a high-volume buyer of gas and electricity for most of the Dutch ceramics manufacturing industry.
Steenfabriek Huissenswaard with its “Caprice Baksteen” brand is a family-owned enterprise that can look back on roughly 150 years of experience in producing masonry bricks. The clay for these bricks comes from the riverbeds of the Rhine, Waal, Ijssel and Maas rivers. Additional clay sources are located in Germany's Eifel and Westerwald regions. Each year, 75 million bricks roll out of Huissenswaard's gas-fired tunnel kiln in Angeren. The entire plant uses ten million cubic meters of natural gas per year. The gas costs account for one-third of each bricks’s manufacturing costs.