Executive Summary : | The industry dealing with production of fruit juice, wine, flower and vegetable has the huge contribution in the economic support to our country. Although, the useful products of these industries (i.e., fruit juice, wine, flower bouquet, vegetable, etc.) are consumed. But, the problem arises when residual and non-useful products (e.g., fruit pulp/peels, pomace, vine shoot, grape stalks, pruned flower stems/leafs, rotten/discarded part of vegetable, etc.) are dumped into open environment. Such type of wastes gets accumulated on daily basis (400 MT/year) which is becoming threat in terms of toxicity of air, water and soil pollution. To digest such wastes, the hydrothermal carbonization (HTC), is attracting the attention of researchers due to its unique feature of low temperature (180-280 oC), minimum time (minutes to few hours) and moderate pressure (2-10 MPa) requirement. It holds the ability to use wet biomass wastes (as is the condition) which saves energy required for drying the feedstock. It uses the subcritical water for conversion of biomass to green coal (i.e., hydrochar) by the combining the process of hydrolysis, dehydration, decarboxylation, condensation, polymerization and aromatization. During the operation of HTC reactor, the pressure inside the reactor increases iso-tropically. The efficacy of waste to energy conversion by HTC reactor can be further improved by combing the process with anaerobic digestion (AD) of HTC liquor to obtain biogas. Therefore, the HTC in combination with AD will be helpful to recover maximum amount of energy in form of green coal (i.e., hydrochar) and biogas (i.e., mixture of CH4, H2, etc.). The HTC of waste biomass is becoming noticeable as it is as scalable technique for conversion of wet biomass (e.g., MSW) to carbon rich solid fuel. HTC offers many advantages as the most efficient process for maximum fixation of carbon in solid fuels form a wet feedstock, in a short residence time. The advantages of HTC include: (i) does not require separation of feedstock (ii) ability to use wet feedstock without drying (iii) faster processing time (minutes to few hours) and (iv) lower operating temperature (180-280 oC) requirement than conventional thermal-treatment methods (e.g. pyrolysis (500-600 oC), gasification (600-1000 oC), incineration (800-1000 oC)). The previous published papers imply that there is huge possibility to convert the wet industrial waste biomass (obtained from industries dealing with making juice and wine, floral and vegetable) to energy rich products. It will benefit in two ways: (i) production of green coal (i.e., hydrochar) which will serve as fuel, fertilizer, adsorbent, super capacitor and anode making material etc., (ii) the liquid byproduct of HTC can be processed to produce biogas by AD, and (iii) no formation of harmful residue. Therefore, HTC+AD will be helpful to recover maximum amount of energy from industrial waste biomass (IWB) and maintenance of pollution free environment. |