Corn processing in Colombia

Today, however, rather than sniff the wind emanating from the plant, processes specialist Hugo Sacristán patrols the site at ease and marvels at the technological changes that the Cali wet-milling and corn-processing plant has undergone in the past few years. ‘‘The changes here have been constant, at times dramatic, and today the plant is almost completely automated,’’ he says. ‘‘I know all the refining plants from Mexico down to Argentina, and without doubt the best technology is here.’’

Industrias del Maiz – Corn Products Andina is a wholly-owned affiliate of the Westchester, Illinois-based Corn Products International, one of the world’s largest producers of corn-derived products, with dozens of plants worldwide. However, the plant in Cali, an industrial city surrounded by sugar cane fields and nestled in the temperate Cauca River valley, was born as a basic facility for corn starch packaging in 1941 and only became a processing plant in 1959 with an output capacity of 75 tonnes per day.

Since then, the plant’s management has embarked on several small-scale projects to incrementally increase capacity. Yet, the biggest project was not undertaken until the mid-1990s when the decision was taken to construct an entirely new and modern plant on the same site with an output capacity of 350 tonnes per day – and upgradeable to 600 tonnes per day.

The Cali plant is today the largest in the Andean region of South America and daily converts corn and manioc into almost 850 tonnes of a range of sweeteners, starches and oils used in everyday household and industrial products, from sweets to beer and animal feed to adhesives.

Important technological developments

Although Industrias del Maiz still supplies starch for Maizena (its original flagship finished product and a corn starch that is a household name in Colombia) it is marketed as a brand by Unilever. However, today the company supplies a wide range of intermediary products for not only the domestic Colombian market, but also to the US, neighbouring countries such as Venezuela, Ecuador and Peru, and elsewhere in South and Central America. The company also operates plants strategically-located across Colombia in Barranquilla, Cartago and Sabana Grande.

In Cali, many at the plant, from blue-collar workers such as Hugo Sacristán to the upper echelon of professional managers and engineers, say that one of the most significant technological – and cost-saving – developments at the plant is due to the introduction of the evaporation system supplied by Alfa Laval.

Javier Navarro, Engineering and Maintenance Manager at Industrias del Maiz’s Cali plant, says that the decision to introduce Alfa Laval technology – its first application within Corn Products International – has proven to be very successful.

‘‘We are in the process of increasing capacity at our plant in Cali, and we aim to do that within our corporate strategy of excelling at the base business,’’ Navarro says. ‘‘To achieve this we need to use technology that really is state of the art for refining maize, in terms of design quality, reliability, maintenance and safety. The technology that we have employed from Alfa Laval meets the specification in all of these categories.’’

Large energy savings

The process that converts corn to products such as corn syrup and modified starches is long. It begins with the importation of corn, mostly from the US, and manioc, which is supplied from within Colombia. Next, instead of being crushed by mill stones, the corn is allowed to macerate for 48 hours in large tanks containing sulphur diluted in water. This softens the corn ready for the following stage and the water increases its sugar and protein content so that it can be converted into ‘liquor’.

It is at this next stage that Alfa Laval has revolutionized the process with its threeeffect evaporation and condensation system. The corn ‘liquor’ passes through the AlfaVap evaporator that removes some of the water thereby reducing the volume and leaving a more concentrated liquid called ‘heavy corn steep water’.

The three-effect evaporation and condensation system.At this stage, the ‘steep water’ can be easily converted into one of the first finished products: a protein-rich substance for use as a component of bovine animal feed. Several AlfaVap evaporators in series allow the ‘steep water’ to be further concentrated. This intermediate material passes through the new AlfaCond 600 plate condenser that condenses vacuum vapours.

In addition, in other process stages in this corn refining facility, Alfa Laval high-speed centrifuges are used to separate solids that are suspended in liquid.

Navarro says that, from the point of view of corporate finances, the key benefit from the installation of this equipment has been an important saving on operating costs. The type of evaporators and condensers employed previously used more energy as they were less efficient. The AlfaVap and AlfaCond units use about 40 to 50 per cent less energy allowing the capital investment cost to be paid off quickly.

‘‘We reckon the pay-back period is about two years for this equipment, but there are also other benefits for the company,’’ Navarro says. ‘‘In terms of industrial safety, the traditional evaporators operate at 150 psig steam pressure and that carries risks. With the new system, the temperature is lower by about 20 degrees because the energy is recovered inside the condensers.’’

Positive effects on local economy

The Alfa Laval evaporators and condensers have several other benefits, engineers at the plant say. They use only about a third of the space previously occupied by the older traditional system and are easier to install because they are assembled by stacking together a series of parallel ‘plates’, or ‘cassettes’, that slide on rails. This also allows for the capacity of each unit to be adjusted and expanded in case of further plant expansion.

‘‘In terms of regular maintenance it’s also much quicker and the reassambly of the heat exchanger plates is much easier,’’ says Luis Aranda, senior project engineer at the plant in Cali.

By considerably reducing energy consumption, Industrias del Maiz has also contributed to environmental conservation in Colombia which sometimes suffers from energy and power shortages. Cost savings at the company have also allowed it to invest in expanding its Colombian domestic supply of raw materials, including corn, and in particular manioc, known locally as yucca. This, the company calculates, has allowed it to create 6 000 jobs directly and indirectly, benefiting the economy and the population in nearby areas.

Navarro is in no doubt about the benefits that Alfa Laval evaporation, condensation and heat exchanger technology has brought to the Cali corn-processing plant and how its benefits could be replicated in other areas of the Corn Products International group. ‘‘Given the potential benefits that it has, I would recommend that in the future it be considered as an alternative technology that can provide major benefits over the traditional methods.’’

But perhaps the last world should go to ‘old timer’ Hugo Sacristán who started work as a corn miller 35 years ago.  “A lot has changed with the equipment at the plant. And you have to change with the technology.” 

Alfa Laval / Industrial del Maiz cooperation

Industrias del Maiz uses a combination of the AlfaVap evaporator system, the AlfaCond condenser system, plate heat exchangers, and high-speed centrifugal separators as the principal component of the solutions provided by Alfa Laval to improve efficiency in the corn-refining process.

José Angel, master project engineer at Industrias del Maiz’s Cali plant, says that the most important benefits that have been derived from the installation of this equipment are cost savings. ‘‘The AlfaVap and AlfaCond have together given us a reduction of energy consumption of between 40 and 50 per cent when you add together electrical and thermal energy.’’ But there are also other benefits.

José Angel adds: “Other aspects to consider are the area required to install the equipment, that was reduced, and the other element is the flexibility of the equipment. For future capacity expansion we can do it at a very low investment cost and with the minimum amount of operational down-time.’’

Company officials say that the maintenance of the new evaporation/condensation equipment is much easier given the compactness and the ease of reassembly.

Diego Romero, Alfa Laval’s sales manager for Colombia, says that from the design stage through to installation and after-sales service cooperation with the company has been at a maximum. ”The quality of the engineering at the company is the highest and they allowed us to carry out a start-up that enabled us to work within the foreseen time-frame,’’ Romero says. “All told with Corn Products International it’s been a very positive experience for us.’’