Here at Dynamo we’ve taken a look at this problem of fuel
flexibility, and built a power solution that is truly fuel agnostic. While the product we are building requires a
lot of engineering and years of experience (our technical advisory team spans 100+
years of combined turbine development experience), the solution itself has
several key features that allow us to tackle this challenging technical
problem.
The first thing we decided was to build a gas turbine engine,
as they are renowned for their fuel flexibility. In many ways a gas turbine is just a set of
compressors and expanders set around a combustion tube. As long as a combustion chamber can be made to
reliably burn fuel, a turbine can be built around it.
We then developed a combustion chamber that can accommodate
a wide range of BTU contents. The
challenge here was to ensure complete combustion and low pressure loss for a
variety of fuel mixtures at both startup and steady-state operation. The combustion chamber that we have developed
has achieved all of this.
Although the combustion chamber is great, we do not rely on
it 100% to ensure the reliability of our engine. To that end we’ve included a specialized fuel
conditioning system that is closely monitored by our supervisory control system. The fuel conditioning system serves as a
buffer between the wellhead and the combustion chamber, such that the fuel
quality does not vary drastically over short periods of time and reduces the
amount of work needed for the control system to regulate fuel flow.
Deploying our product in the oilfield adds additional complexity. As discussed above, on the fuel supply side the
consistency of the fuel can vary significantly over a few hours, and it is
challenging to quantify that fuel a priori.
Additionally, on the demand side, pump jacks and other field equipment
have a variety of duty cycles which change the amount of power required at any
given moment. To meet these needs, our
solution has to be more than a combustion system. It is tasked with the double duty of
converting a variable energy of one type [fuel] while trying to meet varying
output demands—all within very short time frames. To enable smooth operations, this is achieved
with several features, including a proprietary control system and a
sophisticated custom power electronics package.
We can talk all day about how we do things, but our customers
care about results. In the lab to date
we have verified the ability to operate on fuels ranging from 500-2045 BTU /
scf in a single unit. Across this range
we were able to start the engine, bring it to power, and sustain operations as
the fuel content was varied. We were
also able to do this with liquid water injected into the fuel lines—we were
able to do this with a water cut of 80% by mass. This effective range and the ability to
handle liquids in the combustion system show that we can sustain combustion in
virtually any oil field. A more
technical summary can be found in our whitepaper here.
