How Big is the Pressmud opportunity for CBG production in India?

 

A.      Background:

The article is intended to enlighten the availability of press mud for CBG production in India and competition from alternate usage today and tomorrow.

The press mud is combination of two world press and mud which has a history attached to it. The sugar cane juice after extraction from cane undergo pasteurization process to disinfect any presence of bacterial infection before further processing. The Sterilized juice then treated for removal of mud, organic precipitates which come along the juice extraction process apart from high molecular weight complex sugars which will interfere in production of sugar at later stage of the processing. It literally means the mud recovered from juice clarification is mechanically pressed to recovery maximum possible sugar from it in equipment called Rotary vacuum filter (R.V.F.). The press mud is also called as “maili” in Hindi which means soil contaminated stream. R.V.F. is widely used equipment which needs addition of bagasilo as filter Aid traditionally which are fine bagasse particles which impart cellulose and hemicellulose fractions in Pressmud. These fraction are the only digestible fraction apart from residual sugar in it which is explored for generation of biogas in recent past.

There is one more method rose to fame of mud separation by decanter which due to its inherent limitation haven not received well by most of the sugar factories which separate the mud without requirement of any filter Aid and pressmud from such sugar factories known to yield negligible biogas in various runs by researchers at various levels.

 

B.      Pressmud Production trends and Present usage

The Indian avg sugar production in recent past is about 30-32 MMT and Our sugar cane crushing is about 350-400 MMT on about 500 sugar factories across India. The values could vary here and there a bit but the trend will prevail mostly. The Indian in house sugar consumption is about 25-26 MMT and by an average we used to have roughly 6-7 MMT of sugar is in excess every year in recent past till govt allowed the production of Ethanol under EBP and farmer cane arrear issues built-up apart from cash outflow on export subsidy.

The average pressmud production as per production at 3.5 to 4% w/w of the crushing will stand at 12 to14 MMT per annum.

The most prominent use of pressmud in the history and at present is for bio-composting distillery spent wash which limited the Ethanol production over the years and NGT actions leading to push for ZLD in distillery which is one of the most polluting red category industry.

India has more than 350 distilleries producing about 5-6 Billion liters of Ethanol from sugar bearing feedstock which lead to about 50-60 Billion liters of effluent for disposal.

In recent past Ethanol production has grown mainly on account of incineration boiler for ZLD which reduced requirement of pressmud for composting. Roughly 1-1.5-Billion-liter capacity has Incineration boiler and balance are having Biomethanation route of ZLD with Composting. The effluent disposal of about 4 to 4.5 billion liters worth production literally needs about 10-11 billion liter effluent disposal and at 1-1.5 composting ratio it demands 8-11 MMT pressmud. Which is largely equal to total production in India.

As most of the distilleries shifting to non-composting sustainable route of effluent Managment due PCB pressure and need for increased production due to push from Govt for EBP the pressmud is gradually freeing up. There is slight stagnancy in the plant going for incineration boiler in recent past due to drastic reduction in effluent generation due to use of high sugar bearing fractions from sugar mill for production of Ethanol. This situation lead to impact on economic viability of incineration boiler as a mode of ZLD and exploration of other mode of ZLD a need of the hour.

At the same time spent wash nutrients must go back to sugar cane fields because major nutrient is Potassium which is in abundance in spent wash. Unfortunately India has 100% import of potassium in the tune of 2.5 to 3 million Mt. We have about 5.3 million hectors of Area under cane plantation. The avg. potassium requirement of plant is about 90 to 100 kg/Ha which translate to about 0.53 million Mt i.e. about 20% of the import could be saved by effective use of spent wash as a fertilizer via bio-compost or any other rout of recycling spent wash to cane fields.

As most of the consumption is for composting in their own distillery or offtake by some standalone distillery unit in some cases never ever stressed / posed press mud as a disposal issue and if some small quantity demand disposal then storage in yard for 20-30 days reduces its volume by 1/3^rd which reduced the scale of issue as off now.

So with this back ground whosoever speaks to sugar industry they will not project pressmud as issue due to in-house consumption avenues and excess if any at location could be used for building relation with farmer by giving it to them as Fertlizer.

However, spent wash bio-composting is still a mode of spent wash disposal than fertilizer production facility. The profitable ways of fertilizer offtake and marketing is still a challenge to address to the greater extent.

As the mud portion is coming from Farm and anyways goes back to farm as humus after composting.  The bagasilo portion which is Actually part of bagasse has organic which could be converted to biogas which slightly difficult ways than selling it as fuel in local brick kilns in UP and other part of India was a regular affair for disposal as offtake was always been issue for bulk quantities until NGT crackdown on such kilns on pollution aspect in northern India.

As more and more distillery will shift to non-composting based ZLD routes pressmud will gradually open up and build as issue for disposal if not converted to Biogas in coming time.

The surplus sugar has potential to produce about 3.5 to 4.5 Billion liter of Ethanol as of now where as our requirement based on NITI Aayog projection will be over 10 Billion liters which need a serious after though about feedstock’s and technology if our internal sugar consumption not gone down to free up the extra sugar or innovative farming technology which will increase the sugar cane yield for EBP in near future which looks one of the major challenge and hurdle in the Ethanol boom to sustain in near future.

 

C.      Future usage of Pressmud and facts

EBP is been significant part of Indian energy dashboard in recent part and industries along with technology suppliers looking out to various feedstock which could be potentially converted to Ethanol or liquid biofuel economically.

Pressmud could be converted to pellets for combustion after drying by small sugar factories is near future due to restriction on composting and unviability of CBG plant due to viable capacity. Pressmud like high ash fuels will pose its own challenges in disposal for sure but due to disproportionate increase in coal prices use of pressmud for fuel gained lot of traction in recent past. How sustainable way of utilizing pressmud is to be seen in near future with overall impact of environment.

Bagasse could be one of the potential product moving forward can be converted to CBG as Power PPA has seen downward trends in recent past and no significant upward movement is expected in time to come. However existing investment in co-generation plants will largely limit this shift considering majority of investment in cogeneration plants is on BOOT basis. The avg available free bagasse in today’s scenario is about 10-20 MMT which is mostly used as fuel, paper and board manufacturing India at on date.

As paper and board are value selling products can afford cost variations apart from fuel application at some locations so overall project economics will drive its conversion to various byproducts in near future. The is possibility of conversion of bagasse to 2G ethanol at prohibitive price for private investor as on date and any update moving forward will be interesting to watch out. These value are really good indicator for industry to chalk out the business goals in near and immediate future.

I personally feel use of pressmud and bagasse to extract maximum value by converting it to CBG for mills would be potential option to evaluate.

 

D.      Conclusion and Recommendations moving forward

a.       Pressmud will pose major disposal issue in near future if not converted to value added co-product such as CBG by sugar industry.

b.       Pressmud  and bagasse to Ethanol using 2G Biomass to Ethanol technology being lignocellulose based substrate and overall process will be distance possibility and troublesome due to handling and investment number in such technology.

c.       Pressmud will be available more and more in coming future as NGT will tight grip on red category industry looking at present ZLD technology credentials apart from Slop fired boilers which is largely a known devil in ethanol industry.