Sugar’s Pressmud for Green Energy Production | 01 Dec 2023

Source: DTE

Why in News?

India is viewing Pressmud, a residual byproduct of Sugar, as a valuable resource for green energy production by creating Compressed Biogas (CBG).

• India holds a key position in the worldwide sugar economy, emerging as the foremost sugar producer since 2021-22, surpassing Brazil. Additionally, it stands as the second-largest sugar exporter globally.

What is Compressed Bio-Gas (CBG)?

• CBG is a Renewable, environmentally friendly gaseous fuel derived from the anaerobic decomposition of organic materials. It is produced through a process called Biomethanation or anaerobic digestion, where various organic sources such as agricultural waste, animal manure, food waste, sewage sludge, and other biomass materials are broken down by bacteria in the absence of oxygen.
• The resulting biogas primarily consists of methane (usually over 90%), carbon dioxide, traces of hydrogen sulfide, and moisture.
• To convert biogas into CBG, purification steps are employed to remove impurities such as carbon dioxide, hydrogen sulfide, and moisture.
• The purified methane gas is then compressed to a high pressure, typically around 250 bar or higher, hence the term "Compressed Biogas."

What is Pressmud?

• About:
  • Pressmud, also known as filter cake or press cake, is a residual byproduct in the sugar industry that has gained recognition as a valuable resource for green energy production.
  • This byproduct offers Indian sugar mills an opportunity to generate additional revenue by utilizing it as a feedstock for biogas production through anaerobic digestion, leading to the creation of Compressed Biogas (CBG).
    • Anaerobic digestion is a process through which bacteria break down organic matter—such as animal manure, wastewater biosolids, and food wastes—in the absence of oxygen.
  • Typically, the yield of pressmud ranges from 3-4 % by weight with the input sugarcane processed in a unit.

• Advantages of Pressmud Utilization for CBG Production:
  • Fewer Complexities: Its advantageous qualities include consistent quality, simplicity in sourcing, and fewer complexities compared to other feedstocks.
  • Simplified Supply Chain: It eliminates the complexities associated with the feedstock supply chain, as found in the case of agricultural residue, where biomass harvesting machinery is required for harvesting and aggregation.
  • Single Sourcing: The feedstock is sourced from one or two producers or sugar mills, as opposed to agricultural residue, which involves multiple producers / farmers within a narrow window of 45 days per year.
  • Quality and Efficiency: Quality consistency and higher conversion efficiency, requiring less feedstock quantity compared to alternatives like cattle dung.
    • Approximately 25 tonnes of pressmud are needed to produce a tonne of CBG. In comparison, cattle dung requires 50 tonnes for the same gas output.
  • Cost-effectiveness: Lower cost (Rs 0.4-0.6 per kilogramme) compared to other feedstocks like agricultural residue and cattle dung. It eliminates pretreatment costs as it lacks the organic polymer lignin, unlike agriresidue.
• Challenges Faced by Pressmud Utilization:
  • Pressmud faces challenges such as escalating prices, competition for usage in other industries, and storage complexities due to gradual decomposition, necessitating innovative storage solutions.
    • As an organic residue, it is sought after in sectors like animal feed, bioenergy production (for biogas or biofuels), and agricultural soil amendments. This competition can sometimes limit its availability or increase its cost for specific applications.

What is India's Pressmud Production landscape?

• Production Statistics:
  • In the fiscal year 2022-23, India's sugar production reached 32.74 million tonnes, generating about 11.4 million tonnes of pressmud.
• Sugarcane Growing States:
  • The primary sugarcane-growing states, notably Uttar Pradesh and Maharashtra, contribute significantly, covering approximately 65 % of India's total sugarcane cultivation area.
    • Key sugarcane-producing states include Uttar Pradesh, Maharashtra, Karnataka, Tamil Nadu, and Bihar, accounting for a substantial portion of India's overall sugarcane production.

Way Forward

• To harness the full potential of pressmud for CBG production, various interventions are crucial:
  • State-level Policies: Implementation of supportive bioenergy policies by states, streamlining approval processes and offering incentives.
  • Price Control Mechanisms: Establishing mechanisms to control pressmud prices and encouraging long-term agreements between sugar mills and CBG plants.
  • Technological Advancements: Research and development for efficient pressmud storage technologies to prevent methane emissions and minimize gas loss.
  • Training Initiatives: Conducting training sessions for CBG plant operators on plant operations, scientific equipment handling, and feedstock characterization.