[Gasification] OT - two stroke engine

[Peter Singfield]

At 11:26 AM 6/3/2007 -0600, Bob Stuart wrote:
>
>It seems to me that both sides will stabilize around the temperature  
>of the working fluid as it averages in that location, and you will  
>always have to add power to overcome friction. I've never heard of a  
>heat engine that does not exploit a difference in temperature.  This  
>scheme seems to violate the second law of thermodynamics.  Heat is a  
>lower  form of energy than momentum or electricity, so while they can  
>produce heat directly at 100% efficiency, the exchange can't be  
>reversed directly, and must be approached by interfering with the  
>mixing of hot and cold.  Where only a small temperature difference is  
>available, as in the ocean thermal schemes, the efficiency is  
>extremely low.
>
>Best,
>Bob
>

One solution to this dilemma is adding an exhaust -- then doing the phase
change dance.

Quick calculations of over all efficiencies can usually be done by the
Delta-T factor.

Delta-T being the distance between two temperatures.

Basically -- with steam -- you need to start with 1000F an over and end
with 212F or less to get any kind of a decent return -- 

The Uniflow design worked so efficiently because it actually went below 212F!!

More later -- maybe --

And oh -- how is this related in any way to Gasification??

Well -- for small system -- terribly much so.

A simple boiler and steam powered prime mover would make thermal gasifiers
the best deal on the market place -- except for two things.

1: the need of going to such high quality steam to get nay kind of over all
efficiencies (else your lucky to even reap 3% over all!!)

2: the extreme cost and security issues involved with high quality steam
plants

My goal it to get at least 20% system efficiency -- using a thermal
gasifier to steam power plant route -- at a very small and economic scale.

This should be of great interest to all gasifiers??

Two options -- go "ORC" or go steam.

ORC is rather expensive to ---

More later -- maybe ---

Peter