Integrated Combined Heat and Power Using    Ultra-Low NOx Supplemental Firing       

This page updated January 19, 2005.

Gas Technology Institute

Integrated Combined Heat and Power Using
Ultra-Low NOx Supplemental Firing

Technology and Innovation
The Gas Technology Institute (GTI), along with its partners Coen Company, Solar Turbines, and Capstone Microturbine, propose to develop and demonstrate a combined heat and power (CHP) system design using a novel supplemental burner with reburning features. This CHP, combining the advanced burner technology with state-of-the-art gas turbines by Solar and Capstone, can meet proposed 2007 ARB NOx and CO targets for CHP installations without the use of end-of-pipe cleanup technology such as selective catalytic reduction (SCR). The supplemental burner, designed by GTI to be installed between the gas turbine and heat recovery boiler or absorption chiller, combusts natural gas using the turbine exhaust gas (TEG) as oxidant, just as current duct burners do. However, this burner uses a unique combination of staged combustion and engineered internal recirculation to create a reburning zone that actually reduces NOx and NOx precursors present in the TEG. The additional fuel combustion adds very little NOx and effectively completes combustion, keeping CO at very low levels in spite of the suppression of thermal NOx, which generally is difficult to achieve without raising CO emissions. Lab tests with a 2 million Btu/h burner firing with exhaust gas from a 60 kW Capstone microturbine have already proven the ability of the system to reduce NOx formed in the turbine and deliver final NOx emissions in the stack at levels never before achievable without SCR.
Emission Benefit
Supplemental firing can boost heat output and thermal efficiency from gas-turbine-based CHP in a cost-effective manner, but ARB 2007 NOx targets can currently be met only with the addition of Selective Catalytic Reduction (SCR), which increases capital cost by 10% to 25%. This is a significant barrier to adoption of CHP, especially by small to medium-capacity facilities (15 MW or less). The proposed ULN supplemental burner with reburning features can remove this barrier by eliminating the need for SCR. We estimate that the ULN supplemental burner adds no more capital cost than a conventional duct burner, and that cost will be recouped in less than 1.5 years through increased energy efficiency. NOx level in the stack from the integrated CHP using this advanced burner will be as low as 0.033 lb/MW-hr output, which is more than 50% below the 2007 ARB targets. Similarly, CO levels have been measured well below the proposed 2007 target of 0.10 lb/MW-hr output.
Project Descriptioin
GTI and the project team will scale up the burner to 10 million Btu/hr for extensive testing in our lab using simulated TEG at approximately 250 kW scale. Burner specifications will be developed for a range of CHP options based on Capstone and Solar gas turbine models, and a host site will be sought for 5 MW field demonstration. The host site will be an industrial customer for Solar's new Mercury 50 recuperated gas turbine, and the CHP will be designed to meet the NOx target of <0.07 lb/MW-hr output without the use of SCR. We estimate the burner size to be in the range of 40 to 60 million Btu/hr. A test campaign will be conducted to obtain long-term parametric and reliability data, followed by drafting of a technology transfer and commercialization plan.

Funding Source

Funding Amount


$  249,274


$  753,681

California Energy Commission, Coen Company,
Solar Turbines and Capstone


ICAT Funded Projects