#*---------------------------------------------------------------------
* EMSO Model Library (EML) Copyright (C) 2004 - 2007 ALSOC.
*
* This LIBRARY is free software; you can distribute it and/or modify
* it under the therms of the ALSOC FREE LICENSE as available at
* http://www.enq.ufrgs.br/alsoc.
*
* EMSO Copyright (C) 2004 - 2007 ALSOC, original code
* from http://www.rps.eng.br Copyright (C) 2002-2004.
* All rights reserved.
*
* EMSO is distributed under the therms of the ALSOC LICENSE as
* available at http://www.enq.ufrgs.br/alsoc.
*
*----------------------------------------------------------------------
* 6. Heat exchange in a series of tanks
*----------------------------------------------------------------------
*
*   Description:
*      This problem is part of a collection of 10 representative
*	problems in Chemical Engineering for solution by numerical methods
*	developed for Cutlip (1998).
*
*   Subject:
*       * Heat Transfer
*
*	Concepts utilized:
*		Unsteady-state energy balances, dynamic response of well mixed
*	heated tanks in series.
*
*	Numerical method:
*		* Simultaneous first order ODEs
*
*   Reference:
*		* CUTLIP et al. A collection of 10 numerical problems in 
*	chemical engineering solved by various mathematical software 
*	packages. Comp. Appl. in Eng. Education. v. 6, 169-180, 1998. 
*       * More informations and a detailed description of all problems
*	is available online in http://www.polymath-software.com/ASEE
* 
*----------------------------------------------------------------------
* Author: Rodolfo Rodrigues
* GIMSCOP/UFRGS - Group of Integration, Modeling, Simulation, 
*					Control, and Optimization of Processes
* $Id$
*--------------------------------------------------------------------*#
using "types";



#*---------------------------------------------------------------------
*	Model of a stream
*--------------------------------------------------------------------*#
Model oil_stream
	PARAMETERS
	W		as flow_mass	(Brief="Mass flow rate", DisplayUnit='kg/min');
	cp		as cp_mass		(Brief="Heat capacity of the oil", DisplayUnit='kJ/kg/K');
	
	VARIABLES
	T		as temperature;
	
	SET
	cp = 2*'kJ/kg/K';
	W = 100*'kg/min';
end

Model tank_source
	ATTRIBUTES
	Pallete = true;
	Brief 	= "Simple inlet stream";
	Icon	= "icon/tank_source";
	
	VARIABLES
out Outlet 	as oil_stream	(Brief="Outlet stream", PosX=1, PosY=0.5);
end

Model tank_sink
	ATTRIBUTES
	Pallete = true;
	Brief 	= "Simple outlet stream";
	Icon	= "icon/tank_sink";
	
	VARIABLES
in 	Inlet	as oil_stream	(Brief="Inlet stream", PosX=0, PosY=0.5);
end


Model heat_stream
	VARIABLES
	T		as temperature;
end

Model steam
	ATTRIBUTES
	Pallete = true;
	Brief 	= "Simple inlet stream";
	Icon	= "icon/tank_source";
	
	VARIABLES
out Outlet 	as heat_stream(Brief="Outlet stream", PosX=1, PosY=0.5);
end


#*---------------------------------------------------------------------
*	Model of one tank
*--------------------------------------------------------------------*#
Model heated_tank
	ATTRIBUTES
	Pallete = true;
	Brief 	= "Simple model of a steady-state CSTR";
	Icon	= "icon/heated_tank";
	
	
	PARAMETERS
	UA		as Real			(Brief="Product of the heat transfer coefficient and the area", Unit='kJ/min/K');
	
	
	VARIABLES
in	Inlet  	as oil_stream 	(Brief="Inlet stream", PosX=0.51, PosY=0);
out	Outlet 	as oil_stream 	(Brief="Outlet stream", PosX=1, PosY=0.975);
in	InletQ 	as heat_stream	(Brief="Rate of heat supply", PosX=0, PosY=0.715);
	
	M		as mass			(Brief="Mass in tank");
	Q		as heat_rate	(Brief="Rate of heat transferred", DisplayUnit='kJ/min');
	
	
	SET
	UA = 10*'kJ/min/K';
	
	
	EQUATIONS
	"Energy balance"
	(M*Outlet.cp)*diff(Outlet.T) = Inlet.W*Inlet.cp*(Inlet.T - Outlet.T) + Q;
	
	"Rate of heat transferred"
	Q = UA*(InletQ.T - Outlet.T);
end



#*---------------------------------------------------------------------
*	Three tanks in series
*--------------------------------------------------------------------*#
FlowSheet series_of_tanks
	VARIABLES
	feed	as oil_stream;
	
	
	DEVICES
	steam1	as steam;
	steam2	as steam;
	steam3	as steam;
	
	tank1	as heated_tank;
	tank2	as heated_tank;
	tank3	as heated_tank;
	
	
	CONNECTIONS
	feed		 to tank1.Inlet;
	tank1.Outlet to tank2.Inlet;
	tank2.Outlet to tank3.Inlet;
	
	steam1.Outlet to tank1.InletQ;
	steam2.Outlet to tank2.InletQ;
	steam3.Outlet to tank3.InletQ;
	
	
	SPECIFY
	feed.T = (20 + 273.15)*'K';
	
	steam1.Outlet.T = (250 + 273.15)*'K';
	steam2.Outlet.T = (250 + 273.15)*'K';
	steam3.Outlet.T = (250 + 273.15)*'K';
	
	tank1.M = 1000*'kg';
	tank2.M = tank1.M;
	tank3.M = tank2.M;
	
	
	INITIAL	
	tank1.Outlet.T = (20 + 273.15)*'K';
	tank2.Outlet.T = tank1.Outlet.T;
	tank3.Outlet.T = tank2.Outlet.T;


	OPTIONS
#	Dynamic = false; # steady-state
	TimeStart = 0;
	TimeStep = 1;
	TimeEnd = 90;
	TimeUnit = 'min';
end