GE’S RO technology helps Cia Nitro Química reduce natural gas consumption, greenhouse gas emissions, water consumption and the generation of wastewater

CHALLENGE

With 19 million inhabitants, the metropolitan region of São Paulo , in Brazil , is one of the five most populous cities in the world. Since 1980, its population has more than doubled, also turning it into the largest industrial center in Brazil . Although this rapid growth has increased economic development, it has also considerably increased the pollution of the air and water, especially in the city’s two principal rivers, the Tietê and the Pinheiros.

To conserve water and reduce the emission of effluents, and other environmental pollutants, many local factories are installing more environmentally friendly systems, the decrease the consumption by these industrial units, in addition to reducing the emission of contaminants.

A Cia Nitro Química Brasileira is one such example, having reduced natural gas consumption by 45% and consequently, reducing the emission of gases and the discharge of effluents from the boilers by 90%. As one of the leading chemical industries, the plant produces 328 thousand tons/year of nitrocellulose, fluorhydric acid, aluminum fluoride and sulphuric acid utilized in a wide variety of sectors, including the manufacture of varnishes and lacquers, aluminum, herbicides, fertilizers, as well as the chemical, steel, petroleum, alcohol fuel, paper and cellulose industries.

The plant’s production process demands a significant volume of high purity demineralized water, to generate steam. In order to reduce water consumption and reduce the emission of effluents, the plant opted for the installation of a system of demineralization through the reverse osmosis technology of GE Water & Process Technologies.

The factory workers noticed that the water softening process that was being utilized did not produce water of sufficient quality to refill the boilers. The formation of scale and incrustations considerably reduced the thermal exchange and consequently, the efficiency of the boilers, significantly elevating the consumption of energy. The cost of maintenance was very significant and compromised the availability and reliability of our systems. In order to minimize these problems, regular emptying and bleeding off of discharge water in the boilers was necessary, which caused an increase in the consumption of water and effluents, greater consumption of fuel, chemical products, etc. The problem was aggravated with the installation of the compact boiler, with a greater vaporization charge.

SOLUTION

These operational difficulties, together with the company’s desire to reduce natural gas and water consumption, led to the plant opting for improvement of its steam generation system with the installation of a system of reverse osmosis (RO) from GE Water & Process Technologies and new economizing measures.

“We chose the RO system from GE because of the company’s excellent reputation, competitive financial proposal, and a guarantee that it would meet our strict performance standards”, affirmed Rosan Coutinho, energy department manager, who is responsible for the distribution of utilities and plant production of sulphuric acid.

RO is a mechanical process involving the reversal of flow through a semi-permeable membrane from a solution with a high concentration of mineral to the high purity or “permeated” stream, on the opposite side of the membrane. The driving force for the separation is pressure.

Results

With regard to the high purity water produced by the reverse osmosis system in GE, the effluents from boiler discharge were reduced by 90%, reducing as well, the loss/waste of energy. The reduction of effluents was 106,200m3/year (2.5% of the total plant), and the consumption of water in an equivalent amount. These reductions, in turn, reduced the relative costs relative to industrial wastewater by US$ 75,000/year and the consumption of water in US$ 29,500/year

Now, the boilers operate almost continually, without the frequent interruptions required by the previous water treatment system. In addition, the boilers now operate in compliance with the ASME/ABMA directives.

The incrustations which formed within the boilers were minimized substantially, and now, they operate in a more efficient manner. The plant has therefore reduced natural gas consumption by 7,461,000m3/year, reducing proportionally the environmental greenhouse gas emissions.

As a result, the company has directly saved US$ 2,070,000/year. In addition, the more efficient operation has enabled Cia Nitro Química to reduce its electrical energy consumption by 6,672 MWh/year, resulting in an annual savings of US$ 320,000.

“The project has met our expectations for financial gains, operational efficiency, and environmental benefits”, said Coutinho. “In financial terms, the RO system was easily justified, showing an excellent return on our investment. And, as a business with 70 years of history with a deep commitment to this region, the environmental benefits are also extremely important to us.”