Global Cement speaks with Heber Barrios, plant manager at Cementos Progreso’s San Gabriel plant, the most modern cement plant in Central America.
Global Cement (GC): Please could you introduce the history of the San Gabriel plant?
Heber Barrios (HB): The San Gabriel plant is located in Guatemala, Central America. It was the third plant built by Cementos Progreso and was constructed to the north west of Guatemala City. It was conceived in the late 1990s to meet the expected increase in domestic cement demand and expansion plans in the region.
However, the plant did not produce cement until December 2018, nearly 20 years after it was conceived. It began commercial production in early 2019, which means that we have now been operating for three years. The long delay was due to the late 2000s financial crisis, which led to lower demand for cement in the local market. The company was confident enough to restart the project in 2014 and spent four years developing the site and constructing the plant.
GC: Four years is quite a while to build a plant like this. Were there some delays?
HB: Indeed, it is technically feasible to launch a plant like this in two years, or even less, but that doesn’t take into account the full range of factors at play here. Most significantly, the area surrounding the plant is among the least developed in the country. As a company that wanted to fit in well with its host communities, we also wanted to employ more than 60% local workers. However, this required significant training, as most people are only educated to a primary school level. We spent significant time inviting people to the site, educating them about the plant and essentially developing our own workforce, while contributing to the wider society. We are really proud of this achievement.
As well as this, we had to build significant infrastructure connections between the main road network. This meant that some of the biggest pieces of equipment had to come in via narrow local roads, sometimes unpaved. This was a slow and delicate process. The power grid was also not available, so we had to construct a 25MW diesel-powered electricity plant just to get the site powered.
Production process
GC: Please could you outline the cement production process used at the plant?
HB: The main components of the production line were supplied by thyssenkrupp Industrial Solutions (tkIS). This starts with the crushing plant in our quarry, which has a primary impact crusher capable of crushing 1700t/hr on a dry basis. It has a reduction ratio of 20:1, which leads to a product size where >95% passes 80mm. Then follows a ThermoFisher online analyser, followed by our 1.7km overhead ROPECON conveying system from Doppelmayr.
Preblending and reclaiming is taken care of in two tkIS longitudinal pre-blending piles, each with a capacity of around 25,000t. Linear is not my first preference, as we have some inconsistency with the homogeneity at the ends of the pile.
For raw material grinding and kiln feed plant we have a Quadropol vertical roller mill that is capable of grinding 375t/hr at a fineness of 12% residue on 90-micron sieve. There is then a 10,000t homogenising silo.
On to the pyroprocessing line, the plant is equipped with a two string, five-stage Dopol preheater, a Prepol calciner and 75m Polro kiln that can produce around 4500t/day of clinker. This is followed by a Polytrack clinker cooler and a 70,000t clinker storage silo.
For clinker grinding, the plant has two Quadropol vertical roller mills, each capable of manufacturing 220t/hr at a maximum fineness of 5300cm2/g, according to Blaine. This is held in four storage silos that jointly share a capacity of 30,000t.
Around 90% of our cement is despatched in bags, so we have two Haver & Boecker packing lines, each able to pack 3600 42.5kg paper bags per hour. There are also two palletisers that pack these in a five bag bonded pattern on slip-sheets.
GC: What cement types are made?
HB: The San Gabriel plant manufactures three types of cement. General use cement branded as UGC comprised around 70% of our sales in 2021. We also produce CFB, which is used for manufacturing aerated blocks. This represented around 20% of sales in 2021. Finally, around 10% of our output in 2021 was BRA, a cement that exhibits low reactivity with high alkali aggregates.
GC: Where does the plant source its additives?
HB: Most of our correctives and additives, including pozzolan, sand, gypsum and alumina, come from internal sources or local third parties. They are crushed in a dedicated additive crushing plant that has a capacity of 450t/hr for limestone, pozzolan and gypsum. It is important to point out that our high use of pozzolan, around 30% across our entire product range, ensures a very low embodied level of CO2 emissions relative to many in the market.
GC: What fuels does the plant use?
HB: Petcoke has been the main fuel for Progreso kilns for more than 30 years, and the San Gabriel kiln is no exception. More than 95% of energy comes from this fuel, with around 5% bunker oil. The petcoke is ground in a tkIS ball mill at 25t/hr, which gives a fineness of 3% residue on a 90-micron sieve.
Of course, in the future, this modern line allows us to introduce alternative fuels. We have a project to feed whole tyres to the calciner, with a launch scheduled for May or June 2022. This will bring our alternative fuels rate to 5 - 7%.
This is not a technical problem for the plant. The problem is that getting petcoke in Guatemala costs around US$5/MJ. For alternative fuels it is US$7/MJ or more. It is expensive at the moment. To improve this situation, we need to work with the government to encourage better collection and sorting of wastes so that they can be transformed into fuels more economically. Then, we will be ready to take on higher volumes of alternative fuels.
GC: What emissions’ abatement systems does the plant use?
HB: The plant has a rainwater harvesting system, in which all runoff flows into a water reservoir that is used as process water for cooling the equipment. It also has emission meters in fixed sources and in addition to the process dust collectors, throughout the entire production line, there are 70 additional dust collectors to ensure the non-emission of dust into the environment.
With regards to other emissions, there is no limit for NOx in Guatemala. However, the San Gabriel plant has a low momentum burner, which ensures our NOx emissions are in line with international standards. Similarly, SOx emissions are not legally restricted, but we still make efforts to keep our emissions in check.
The San Gabriel plant produces cement with one of the lowest clinker factors worldwide, with a value of 65.2%. This is 11 percentage points below the global average value of the Global Cement and Concrete Association (2019), which is 76.3%.
Markets and the future
GC: Where are the plant’s most important markets and how does it reach them?
HB: All of the cement produced at the San Gabriel plant is sold within Guatemala, mainly to the central and northwestern markets.
GC: How has the Covid-19 pandemic affected the plant’s day-to-day operations?
HB: Throughout the pandemic, it has been a constant concern that we may suffer significant infections among personnel, thus risking their health. Due to self-isolation protocols, Covid-19 also threatens the continuity of plant operations. However, the implementation of anti-Covid protocols has allowed us to manage this risk adequately, while maintaining production.
GC: How did the pandemic affect the market?
HB: I would say that, as far as the cement sector in Guatemala goes, the pandemic was almost ‘invisible.’ Since we opened the San Gabriel plant in 2019, we have seen demand grow to new heights. This made it even more important that we maintain production through the adequate use of anti-Covid measures.
GC: How does the San Gabriel plant fit in with Cementos Progreso’s other operations?
HB: When I first started working at the San Gabriel plant in 2015, the company’s plan was that it would eventually replace the San Miguel plant, which was built in the 1970s. However, due to the strong market demand, this has not yet transpired.
In the future we expect that demand will increase even further. The country currently consumes around 200kg/capita of cement, which is still very low. We expect this to rise in the next 5-10 years. We are already planning to build a second line at the San Miguel plant. Cementos Progreso has the capacity to produce 5.0Mt/yr, so we can supply the country’s demand.
GC: What is the biggest challenge to the plant over the next five years?
HB: The plan in the case of Guatemala is to continue supplying the market, the San Gabriel plant is operating successfully as well as the San Miguel plant, which means we can provide cement both for the local market and certain exports.
GC: What about opportunities for the plant over the same time-frame?
HB: In two words: Alternative fuels. I think we can push the plant up to 20% alternative fuels or more. We are keen to show the community that, far from being a ‘disaster’ for the area, a cement plant can contribute to the circular economy and help to clean up the streets.
There are also opportunities to provide local jobs when we use alternative fuels. For the tyre project we are just installing a belt to feed the calciner. Instead of using one person and a forklift, we will employ 5 - 7 people per shift. Suddenly, instead of creating 2 - 3 jobs, we have 15 or 20. This feeds back into the local economy. For sure, there will be further similar opportunities in the future.
This approach, indeed the success of the San Gabriel project itself, speaks to the confidence and abilities of Cementos Progreso, as well as the people in our host communities. We bet strongly on
Guatemala, and it looks like a good bet right now, and for the future too.
GC: Thank you for a very interesting discussion.
HB: Thank you for the opportunity!