0  otherwise。

1 − exp(−NTU(1 + R))

where,

T = Tge − Tref (29)

εgw =

(13)

1 + R

HSH1  = 32。508  ln P + 2513。2 (30)

where,

(m˙ C)min

HSH2

= 0。00001P2 − 0。1193 P + 2689 (31)

R = (m˙ C)

max

(14)

The mass flow rate of dilute solution in the generator can   be

determined using the energy and mass balances on the generator,

(UA)gw

NTU = (m˙ C)

(15)

as:

m˙ 3  = m˙ 4 + m˙ 7  and x3m˙ 3  = x4m˙ 4 (32)

Heat losses from flue gas and from boiler surface to   ambient

surrounding have been considered in the overall energy supplied by the gasifier, and is given by

The energy balance on the generator is given by,

Q˙ ge  = m˙ 4h4 + m˙ 7h7 − m˙ 3h3 (33)

。 Q˙ aux

。 P8 = P4, T8  can be calculated from Eq。 (25) and h8  can then be

Q˙ PG  = ϕ     ε

+ m˙ fluCp,fluTflu  + (UA)weCp,a(Tb  − Ta)

(16)

obtained by h  = h

h   , where h

and h

are given by the curve fit

gw f

g −  fg

g fg

where, the extracted heat Q˙ bl from the boiler to meet the load can be  calculated from:

equations。 The enthalpy at point 9 can be calculated by considering

the throttling process, as h9 = h8。

hg  = −0。00125397T 2  + 1。88060937T + 2500。559 (34)

Q˙ bl  = ϕm˙ geCp(Tb  − Tge,o) (17) h

0。00132635T 2

The consumption rate of biomass feed stock is obtained from:

fg  = −

− 2。29983657T  + 2500。43063 (35)

LHVPG V˙ PG

m˙ BM  =  y  LHV

     Q˙ PG

= y LHV

(18)

The heat rejected at condenser, where m˙ 7  = m˙ 8, can be deter-

mined by writing the heat balance at condenser as:

G BM

G BM

Q˙ co  = m˙ 7(h7 − h8) (36)

3。3。Absorption chiller

At the evaporator, P10 and h10 can be calculated from the curve fit of Eqs。 (37) and (34)。论文网

The thermodynamic model of absorption chiller was used to simulate its performance with the assumptions presented in  [3]。

P = 2 × 10−12T 6

− 3 × 10−9T 5

+ 2 × 10−7T 4

+ 3 × 10−5T 3

The effectiveness of generator can be calculated as:

。 −(UA) 。

+ 0。0014T 2 + 0。0444T + 0。6108 (37)

ε = 1 − exp

m˙ w Cp

(19)

From the energy balance at the evaporator, the cooling capacity

Q˙ ev  at the evaporator can be calculated from:

At the generator, knowing the hot water inlet temperature and

generator heat flow, the generator temperature can be determined by the following equations: