Techno-economic Assessment of Integrated Hydrothermal Liquefaction and Combined Heat and Power Production from Lignocellulose Residues

Abstract

Waste biomass as a mean for global carbon dioxide emissions mitigation remains under-utilized. This is mainly due to the low calorific value of virgin feedstock, characterized generally with high moisture content. Aqueous processing, namely hydrothermal liquefaction in subcritical water conditions, has been demonstrated experimentally to thermally densify solid lignocellulose into liquid fuels without the pre-requisite and energy consuming drying step. This study presents a techno-economic evaluation of an integrated hydrothermal liquefaction system with downstream combined heat and power production from forest residues. The utilization of the liquefaction by-products and waste heat from the elevated processing conditions, coupled with the chemical upgrading of the feedstock enables the poly-generation of biocrude, electricity and district heat. The plant thermal efficiency increases by 3.5 to 4.6% compared to the conventional direct combustion case. The economic assessment showed that the minimum selling price of biocrude, based on present co-products market prices, hinders commercialization and ranges between 138 EUR to 178 EUR per MWh. A sensitivity analysis and detailed discussion on the techno-economic assessment results are presented for the different process integration and market case scenarios.

Supercritical water gasification of Kraft black liquor: Process design, analysis, pulp mill integration and economic evaluation

“…The solids CHP boiler is modelled similar to a bubbling fluidized-bed design proposed in [ 32,59 ]. Process heat demand is given precedence in utility network design.…”

“…As-penPlus® contains libraries of industrially relevant unit operation blocks that calculate existing chemistry and phase equilibria based on extensive list of thermodynamic routines available in the literature, and compound databases available from the National Institute of Standards and Technology (NIST) Standard Reference Data Program (SRDP) [ 52 ]. Other process modelling tools such as CHEMCAD [ 64 ] and Belsim SA [ 28 ] have been reported, however Aspen Plus® remains the most extensively applied tool in the field [ 37,59,[65][66][67][68][69] ].…”

“…The complete formulation of the optimization routine for the Forrest residue case, as well as the list of experimental references and compounds examined is found in the Appendix of Publication I, as well as in another publication by the author in [ 59 ]. Similar approach is adapted to close the mass balance of the hydro-treatment reactor in the upgrading block in the HTL study cases and in modelling the liquefaction of the lignin component in the WBL mixture in Publication IV.…”

“…The impact of molecular interactions on component's molar volume calculations is accounted for with the use of EOS for gaseous and activity coefficient models for condensed (liquid or solid) phases. The author in [ 59 ] detailed the derivation for the Gibbs minimization calculation routine.…”

Key Characteristics of Carbonized Corncob through Hydrothermal and Pyrolysis Conversion Techniques for Further Activation

“…However, the decrease of specific adsorption with higher hydrothermal temperature could not be conclusive in this study. Nakason et al [13] reported the optimal condition production of hydrochar from corncob as solid fuel which was determined at 200 oC, 3 hour of residence time and biomass to water ratio of 1:5 with maximum energy yield of 68.74%. Magdeldin et al [14] presented the techno-economic performance indicators of integrated hydrothermal liquefaction which densify forest residue lignocellulosic into liquid fuels and combined heat and power production.…”