Massimo Toso, CEO of Buzzi Unicem USA, started the conference by comparing and contrasting the European and US cement industries, pointing out that in Europe cement producers are obliged to take CO2 very seriously, but that there is a ‘clear gap’ between this approach and that of the US. Additionally, he suggested that European heavy manufacturers might be guilty of the sin of hubris over the perception of the cement industry by the public - it is increasingly the case that the public regards the cement industry as an ‘outdated relic,’ or, as another speaker put it, belonging in ‘the cemetery of dinosaurs.’ Massimo exhorted the listening delegates to reach out and to promote the industry. “It might be just a grey powder,” he said, “but many of the greatest accomplishments of humankind in the last two centuries would not have been possible without cement and concrete.”
Ed Sullivan of the PCA next gave his ‘State of the industry’ address. With more than 2m jobs created each year and with the unemployment rate lower than 4.5%, Ed suggested that there may be a further strengthening of US economic growth. This comes despite already tight labour markets and a worsening skills shortage, which will lead to increased wages. The situation might start to unbalance the economy, in terms of inflation, leading to interest rate rises, but at much lower levels than historically. Ed reiterated his forecast of cement demand growth of around 2.5% annually, even in the absence of fiscal stimulus. Some states are still experiencing fiscal problems despite rising tax incomes, since entitlement programmes are growing more quickly than state incomes, and this is squeezing state construction budgets. Ed suggests that there is unlikely to be a Trump Infrastructure Bill before 2019, but even then, the majority of the purported US$1tn earmarked for construction will come from states rather than from the federal government. States and local governments are currently US$3trn in debt so the money might not materialise in the end. The cement intensity of the infrastructure spending is also in some doubt. Ed, in summary, was not optimistic on the real near-term cement industry effects of any Trump Infrastructure Bill. However, he forecast that without significant new capacity in the US, even with imports, that around 2030 the country may face shortages of cement.
The rest of the conference featured parallel sessions, and here we concentrate on selected presentations.
John Kline of Kline Consulting next spoke on the capture of CO2 from the cement industry and its reuse in the concrete industry. Carbon pricing covers around 25% of the world’s emissions, and John suggested that carbon prices will inexorably rise around the world. He suggested that there are a number of different ways of capturing CO2 from the cement production (sorbent technology, membrane, cryogenic) and many uses for the CO2 captured (fuels, plastics, fertilisers, enhanced oil recovery, aggregates), including accelerating the strength gain of concrete through the formation of nano-scale nucleation sites in the concrete mix. Through dosing around 200g of CO2 into a concrete mix, the use of around 9kg of cement per cubic metre of concrete can be avoided.
Lance Clarke, environmental manager at the Roanoke cement plant, next spoke about environmental initiatives at the plant. He suggested that the first and most important step to maintaining a licence to operate is transparency: don’t avoid the neighbours, welcome them; hold open houses- it forces good housekeeping at the plant; provide local information and outreach through regular communications. The plant has also stocked an old quarry pond with trout and keeps bees on the plant site, as well as operating an outdoor classroom facility for local children. The plant continues to have good relations with its close neighbours and stakeholders.
Stefan Laux of Praxair next spoke on the use of a lance to inject hot oxygen into the kiln to reduce NOx and CO emissions. A small amount of fuel is used to preheat the oxygen, to around 1370-1650°C, to form a high-momentum highly-reactive hot oxygen jet. The high velocity oxygen jet, positioned at the kiln inlet, rapidly entrains surrounding gases, oxidising CO and reducing the levels of NOx. The approach can be used alongside SNCR or SCR but has a low capex and no toxic ammonia reagents.
The first presenter in a session on ‘engineered fuels’ was Frederick De Raedt of Alterros, who quoted European standard EN15359 in order to define SRF, which is ‘intentionally produced with respect to quality criteria,’ whereas RDF is usually a remaining fraction from waste treatment operations. Producers of SRF control the production process so that the fuel meets the desired specifications, while RDF is a non-specified waste. SRF has an energy value of 16-20MJ/kg.
Xavier d’Hubert next gave an overview of kiln burners with an eye on the possibility of using more alternative fuels (AF). Burners have evolved over the years, and since the 2000s they have trended towards increased use of AF. A bewildering array of options are available and the choice of burners will depend on the alternative fuels that are available. The Notar gasification reactor is an option for non-direct combustion of alternative fuels, which is perhaps the next step onwards from the Hotdisk and Polysius Step Combustor options for burning bulky alternative fuels.
Ty Howard, plant manager of the LafargeHolcim Devil’s Slide plant in Utah, spoke about the considerations for the use of engineered fuels at the plant, which include air permit conditions, the heat value of the availability of the fuel, market conditions, effects on process parameters and performance in conjunction with other fuels. The plant uses a variety of AFs including tyre chips, nylon fluff and waste plastics.
In an ‘automation’ session, Alistair Brown spoke on behalf of Thermoteknix, on video storage challenges with high-frame-rate high-definition video. In fact, his company’s kiln camera generates 105MB of data per second, or 7TB per day. Compression helps by reducing data volume by 97.5%, down to 2.5MB per second, although this still means 50-100TB of data to store per year. In fact, using ‘intelligent storage management’ to manage and automate storage, the full resolution data is retained for a week, and then one frame per second is retained for 60 days, unless an ‘event’ marker is placed on the system, whereupon the event will be retained in full.
Thomas Walter of Siemens AG pointed out five mega-trends that will influence the cement industry: urbanisation, population growth, climate change, globalisation and digitalisation. By 2020, 40Zettabytes of data will be created each year, with a zettabyte being 1 billion terabytes, from 50 billion connected devices. Alongside these trends other drivers will influence the cement industry, including health and safety, costs and production efficiency. The Internet of Things (IoT) response to these challenges is increased automation and instrumentation, engineering software for the entire plant lifecycle, improved networks, secure data storage and transmission, and software platforms to store and analyse the data. At the moment there are distinct ‘data islands’ that do not talk to each other, in terms of raw materials, suppliers, production and maintenance, logistics and real-time information about supply and demand from customers. Upon full digitalisation, these islands will be fully connected, and able to talk to each other in real time. Application of big data analysis and artificial intelligence to the digitalised system will enable optimisation ‘from quarry to customer.’
Second day
On the second day of the conference, the Portland Cement Association’s chairman Allen Hamblen spoke about the importance of resilience - an attribute that concrete construction has in abundance. The 2017 cost of damage from floods, hurricanes, tornados and fires in the US was over US$300bn and Allen strongly advocated the use of resilient concrete construction, especially in disaster-prone areas. Tax-payer savings are an additional benefit: for each dollar spent on resilient construction, there will be a saving of six dollars on rebuilding costs after a natural disaster. rebuilding costs after a natural disaster.
Evan Reis of the US Resiliency Council next boldly stated that ‘resiliency is the new sustainability.’ He said that there is a focus on the first cost of building, and also on the ‘first environmental cost,’ rather than the lifetime cost of the building. Evan pointed out that Nashville and New Orleans had grown in tandem until Hurricane Katrina hit New Orleans, essentially devastating it. After its devastation, the city has struggled to grow. Evan suggested that if New Orleans had been built with more resilient materials, that it might have been able to survive the disaster and to bounce back more quickly. He reminded delegates that the US west coast is due for a big earthquake, and said that well-built concrete buildings will be extremely resilient when it hits. Concrete-built buildings are likely to be safe in a disaster, the cost of repair is low and the time for recovery will be short.
Franz-Josef Ulm from the MIT CSHub next asked ‘Is concrete the problem or is it part of the solution?’ Without a doubt, reinforced concrete is more robust than wood-based buildings. Franz-Josef also pointed out that wind forces are higher in strongly-ordered groups of buildings (for example built on a grid), compared to a more chaotically-ordered building pattern. Building material is an important factor in building resilience, but it is not the only factor. In a final flight of fancy, he suggested that concrete might eventually be used as an electrical energy storage medium, by dosing the concrete with carbon and surrounding it with insulating materials.
David Fenning of the UC San Diego Deep Decorbonisation Institute next spoke about the use of nanocrystalline catalysts to recycle CO and CO2 into useful fuels. Electrolysis of CO and CO2 into fuels (ethanol, propanol) would certainly work, but David pointed out that a low-cost source of energy is required for the process to be economic. Due to intermittent renewable energy generationnegative-cost energy is available for around 2.5% of the time in California. The EPA estimates that the total societal cost of 1t of CO2 emitted into the atmosphere is around $120, while the current cost of CO2 emission in California is around $15/t. In his experimental process, copper nano-wires are used as a catalyst to produce higher-value fuels, which can be used as a temporary or longer term store of energy, and which can be used as fuel (potentially avoiding the use of fossil fuels).
Peter Kalkert of KIMA next spoke about instrumentation and control of oxy-fuel cement kilns, which use high concentration of oxygen in the kiln atmosphere to generate a near-pure CO2 exhaust gas stream, convenient for capture and use. In order to be able to control the system, a number of gas monitors will be required. Acoustic gas temperature measurement (where the temperature is derived from a measurement of the speed of sound in the process gas) can be used to avoid inaccuracies in other temperature probes caused by thermal radiation. Other sensors might include solid-state oxygen sensors, and high-precision gas flow measurement of dusty gases by cross correlation of sensors.
Later in the programme, Ashok Amin of Bosch Rexroth Corporation, Hagglunds Products Division, spoke about the successful retrofit of a high pressure grinding roll (HPGR) drive. Ashok pointed out that the process of the grinding rolls means that there are large variations in torque experienced at the drive, which had caused a previous drive used at a European cement plant to struggle. A direct hydraulic drive was proposed as a replacement for a previous previous electro-mechanical drive. The two new hydraulic motors operated at 1300NM/bar, with eight 500cc pumps, and were resistant to torque shocks, while being able to operate at nearly constant torque over the entire speed range. Production increased by around 5%, although specific power increased marginally from 30.3 to 30.5kWH/t. Critically, torque on both the floating and fixed rolls was significantly reduced and slippage was reduced to zero, meaning lower wear and maintenance. The payback period for the capital invested, at a cement price of Euro100/t, was about seven months.
After the second day of the conference the delegates were treated to a splendid gala dinner and a number of awards were presented. The Chris Weaver Band entertained delegates long into the night. At the end of the conference, delegates had the chance to tour the extremely impressive Nissan Smyrna car and SUV plant, close to Nashville, to see some of the 900 robots and 8000 workers progressively turning blank metal into smart new vehicles, using just-in-time logistics and advanced manufacturing techniques, all with a good safety record. It was food-for-thought for the traditionally conservative cement industry!