Narendranath, M. Proc. ISSCT, Vol. 25, 2005 A SUGAR PLANT BASED CO-PRODUCTS OPERATION AT THE ANDHRA SUGARS LTD BY The Andhra Sugat#s Ltd, India - 534 21 5 asltnk@vsnl.com KEYWORDS: Sugar Plant, Co-Products, Zero Waste. Abstract THE Andhra Sugars Ltd located in Soutll-Eastern India started operation in 1952 with sugar production, and diversified into the production of various products based on by-products.from the sugar plant. At The Andhra Sugars Ltd, 12 products and electricity are produced, based on by-product fiom the sugar plant. Molasses which is a by-product from the sugar plant is used to produce illdustrial alcol~ol and ethanol. Carbon dioxide, that is a by-product at the alcohol plant, is collected, scrubbed and used in the production of salicylic acid and is also used in the sugar plant. From alcohol, acetic acid, acetic anhydride and ethyl acetate are produced. Aspirin is produced using acetic anhydride and salicylic acid as raw materials. The spent wash froin the alcohol plant is put through a bioaigester, and the bio-gas generated is collected and used as &el in the boiler. The liquid that leaves the bio-digester is sprayed on the press mud from the vacuum filters at the sugar plant to produce bio-earth that is given to the cane farmers for use on their farms. Bagasse is another by-product from the sugar plant. With a cane diffuser, bagasse dryers and high pressure boilers using bagasse and cane trash as fuel, Sugar Unit - I1 generates low cost electricity that accounts for a third of the revenue of this sugar plant. Introduction The Andhra Sugars Ltd commei1ced operation in 1952 with a standard 600 TCD capacity cane sugar plant, that, was expanded in phases, installing a percolation type bagasse diffuser in 1969 and installing a second bagasse difhser in 1981 to handle the entire juice extraction station at the 5500 TCD capacity sugar plant. In 1998, a second sugar plant was built using a cane diffuser at the juice extraction station, doing away with the milling tandem and using a single 5-roller mill for dewatering bagasse. In 2003, improvements were carried out on the diffuser and we have achieved an RME of 98.4 with a pol in bagassl: of 0.80, molasses percent of 4.29 on cane, total losses of 1.5, and a recovery percent of 11.62 on cane, producing a 40 to 50 ICUMSA Colour direct consumption white sugar. Co-products operations As the sugar plant of The Andhra Sugars Ltd is located in a rural area far away from any city, disposal of molasses became a problem. Our technical team set out looking at ways to overcome this problem. The outcome was the building of the distillery and the chemicals plant based on alcohol and other co-products. The different co-products produced at The Andhra Sugars Ltd can be seen in Figure 1. Distillery In 1962, a batch process distillery was built to produce industrial alcohol using molasses fiom the sugar plant as the raw material. In 2001, this distillery was upgraded to a continuous process distillery, and an anhydrous ethanol plant using the molecular sieve technology was added (Figure 2) Chemicals plant In 1962, along with the distillery, a plant was built to produce acetic acid, acetic anhydride and ethyl acetate using industrial alcohol as the raw material (Figure 3). 4 13
Narendranath, M. Proc. ISSCT, Vol. 25. 2005 Fig. 5-The bio-gas production process. Bio-earth production Press mud froin the rotary vacuum filter station at the sugar plant is sprayed with the gas extracted spent wash and composted to produce the bio-earth that is given to the cane fanners to enhance the organic content of their farmland. " Off-crop co-generation In 2000, induced draught type flash dryers that use waste heat from the boiler flue gas were installed at both sugar plants to dry the bagasse from 5 1% to 42% moisture and stacked in bulk to use as fuel for the off-crop co-generation (Figure 6). ELECTRICITY GENERITEE ELECTRICIN GaNSUMED ELECTRlCITY EXPBRTED Fig. 6-Off-crop co-generation process. 5.2 NN\F 0.8 NIVIF 1 4 W The Andhra Sugars Ltd is perhaps one of the very few cane sugar plants that use all by-products to produce value-added products working to achieve zero waste. 416
Proc. ISSCT, Vol. 25, 2005 L'UTILISATION DES CO-PRODUITS DE LA SUCRERIE DE ANDRA SUGARS The Avtdhra Sugar Ltd, India - 534215 asltnk@vsnl.com RBsurnC UNA PLANTA AZUCARERA BASA SUS OPERACIONES EN LOS CO-PRODUCTOS EN LA ANDHRA SUGAR LTD The Andhra Sugar Ltd, India - 534215 asltnk@vsns.com productos, Cero Desechos. Resumen ctricidad a bajo costo que representa un tercio de Sas ganancias de esta planta azucarera. 417