EnCana Cenovus Demonstration Overview

The plant will consist of a plasma reactor assembly, carbon collection and handling, and metering and monitoring of gas composition and calorific value. It will also be equipped with all mechanical and instrumental safety systems. It will draw electricity for the plasma arc from site services to produce HENG in the range of 10% hydrogen by volume in the natural gas. 

The CarbonSaver will be integrated with an advanced control system to provide HENG and control to a legacy 1,100 horsepower, reciprocating internal combustion engine with a mechanical drive to a gas compressor. The general arrangement of the system is illustrated in Figure 1 (below). The CarbonSaver will be equipped with fire and gas detection systems and all mechanical and instrumental safety schemes. An advanced controller will integrate the CarbonSaver and the engine and will be capable of adjusting the air-fuel ratio to broaden the lean burn window of the engine as well as perform on-line diagnostics and execute safety shutdowns. The preliminary plant dimensions are 15 meters long, 5 meters wide and 6 meters high. The core technology consists of the plasma reactor assembly, carbon management system and integration controls.



Figure 1: General Arrangement of the CarbonSaver Demonstration Project

• The CarbonSaver will process sales gas from a distribution line that services the engine.
• This is estimated to be 10 MMBTU per hour with a volume flow of approximately 9.5 thousand cubic feet (MCF) per hour and an inlet pressure of 80 psig.
• The gas composition is approximately 94% methane and 6% other gases.
• The plant will draw approximately 30 kWh of electricity to decarbonize the natural gas at a rate of 6.5 kilograms of carbon per hour and produce HENG with a gas composition of 84% methane, 10% hydrogen and 6% other gases.
• The outlet gas pressure drops to 65 psig while the calorific value of the gas declines 2%, from 1,035 to 1,014 BTU/scf due to the lower energy density of the hydrogen.
• The Wobbe Index also declines from 1,349 to 1,316, however the change remains within the acceptable limits of gas interchangeability.
• To ensure reliable gas delivery to the engine at all times, the system will include bypass valves to circumvent the CarbonSaver during service and maintenance.

The HENG, which has been demonstrated to positively impact the efficiency of internal combustion engines, can also be  transported to markets and delivered to customers through existing pipelines and distribution infrastructure as an ultra-low carbon gaseous fuel to reduce emissions and increase efficiency of end-use equipment and will be demonstrated in future projects. CarbonSaver is ready for implementation in order to evaluate the feasibility of operations at the commercial scale in a natural gas distribution system.

AHI has demonstrated HENG in the range of 5% to 15% hydrogen by volume as an engine fuel is effective at reducing NOx to less than 1 g/bhp-hr range when used in conjunction with lean burn engines and advanced engine control technology. The beneficial impact of HENG extends to include reductions of CO2 in flue gas because HENG is less carbon intensive than natural gas. In testing at the AHI laboratory, we have also seen that HENG increases the fuel efficiency of reciprocating internal combustion engines because the presence of hydrogen reduces misfiring and leads to almost complete combustion of CO and non-methane hydrocarbons. Moreover, the carbon from HENG production has potential applications in metallurgy and rubber, while avoiding emissions associated with conventional carbon production.

As a fully commercial product following the demonstration project, we expect that one CarbonSaver plant feeding 10% HENG to multiple engines at a compressor station, each with a capacity of 1,100 horsepower operating at 40% efficiency and 90% load factor, could reduce NOx emission to the 1 g/bhp-hr range, cut CO2 emissions by 10% to 12% per year and increase useful energy from the engine by 4%. The estimated cost would be equivalent to $0.05 per MMBTU of natural gas or about a 1% premium paid on the price of gas.