Session: 06-09 Advanced Simulation & Testing

Paper Number: 128805

128805 - Negative CO2 Emission Gas Power Plant As Technology for Utilization of Sewage Sludge, Production of Electrical Energy, and CO2 Capture - Case of Chamber Under Transpiration Cooling 

This work focuses on the concept developed in the nCO₂PP project, which aims to demonstrate a technology that allows to achieve negative CO₂ emissions through Carbon Capture and Storage (CCS) applied to sewage sludge. In the concept sewage sludge is first gasified, then the resulting syngas is burned in a semi-closed oxy-fuel gas turbine with pure oxygen and water, using the advantages of oxy-combustion, to ease the capture of CO₂ in the resulting exhaust gases. High-temperature combustion then takes place in a dedicated wet combustion chamber before expansion in a turbine that produce electricity. Given that in Polish law sewage sludge is treated as biomass, negative CO₂ emissions are achieved. Works in the project are carried out both in experimental and computational (design) terms. Experimental efforts include gasification of sewage sludge to obtain a satisfactory calorific value, development of an oxy-fuel wet combustion chamber, and detailed analysis of spray-ejector condenser. Appropriate calculations relating to energy, ecological and economic effects has been discussed in previous articles of authors. The concept of the thermal cycle will be presented, with an indication of islands of devices responsible for individual processes, namely: 1) gasification; 2) combustion of the resulting gas and generation of electricity, and 3) capture of CO₂. The cumulative efficiency is the product of the classic net nCO₂PP efficiency and the gasification process as the multiplication of the efficiency of the two components of the system. The value of the cumulative efficiency was estimated to be 30.18%.  Emission performance, on the other hand, offers CO₂ emissions are -640 kgCO₂/MWh because of the use of a renewable fuel such as sewage sludge.

Economic analyses have been carried out for nCO₂PP in previous conference article, and their results indicate that the investment is profitable with a payback time of 4–6 years, depending on the assumptions made. The main economic returns from the nCO₂PP cycle are due to 3 revenue streams, namely: 1) from the disposal of sewage sludge from the wastewater treatment plant, 2) from CO₂ capture, emissions trading, and fee avoidance, 3) from the sale of electricity. The paper will also show experimental investigation on the technological components developed in nCO₂PP. In particular, the experimental study on the wet combustion chamber with porous wall with transpiration cooling will be presented to. The experiments will show the shape of the flame and demonstrate how water transpiration through porous structures is realized. The additional benefits of the work is to increase awareness and knowledge of negative emission technologies in combination to the disposal of a waste such as sewage sludge.

Presenting Author: Mario Ditaranto SINTEF Energy Research

Presenting Author Biography: 25 years research in combustion and processes related to low carbon technologies

Authors:

Paweł Ziółkowski Gdansk University of Technology
Kamil Stasiak Gdańsk University of Technology
Mario Ditaranto SINTEF Energy Research
Samuel Wiseman SINTEF Energy Research
Dariusz Mikielewicz Gdańsk University of Technology