**6. Conclusions**

56 Distillation – Advances from Modeling to Applications

Compressor power input (kW) 0.518 0.495 Total energy consumption (KW) 9.26 7.26

Rate of column heat loss (kW):

*T T PN <sup>Q</sup> r r*

*d*

Reboiler heat transfer rate (kW):

Coefficient of performance: *HPC* 23 *cp*

Condenser heat distribution factor:

Enweremadu et al, 2008 & 2009)

*Q Q COP W* 

*HPC reb Q f Q*

Overall heat transfer coefficient (kW/m²K):

Qreb = DhD + BhB + L1hLV,e + Qlosses – FhF – Q1 – Q2

*loss <sup>o</sup> ins*

, .

2 . ( ) <sup>2</sup> <sup>2</sup> ln 1

11 1

0.023 ( ) 0.555

*UA K ud C K gh*

*HPC m m LL L <sup>f</sup> pm wall ex m mm L CHP ex*

 

> 

*d K dT T*

 

( )2 ln 1

*s ins ins <sup>P</sup> ins m <sup>s</sup> ins o ins <sup>o</sup>*

 

*<sup>S</sup> <sup>P</sup> amb*

*P t K Nu <sup>K</sup> d P t d t*

Parameter Actual

<sup>P</sup> <sup>2</sup> amb

*o*

*h*

*o*

( )

 

*r*

ins p

0.8 0.4 0.14 3 '

*o v o i wall ex*

Compression ratio 1.22 1.12 Compressor displacement rate (m³/s) 3.88x10-3 3.74x10-3 Compressor heat load rate (kW) 0.13 0.12 Vapour specific volume after compression (m³/kg) 9.49 9.93 Temperature at compressor discharge (K) 395 390 Compressor volumetric efficiency 0.749 0.756 Thermodynamic efficiency 15.8 20.2 Reflux ratio 5.033 7.5

Table 1. Model results of the actual column and control column (Enweremadu, 2007;

2(T - T ) t 1 K

column

2.6 0.7

1.4 0.3

8.7 6.8 (10% of reboiler heat rate)

5.85 6.15

0.3 0.5

(U=Q/A ΔT)

Control column

From the outcome of the study, the following conclusions may be drawn:


The increase in the total energy consumption, reboiler heat transfer rate and the thermodynamic efficiency were appreciable, while there was only a marginal increase

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**3** 

*P.R. China* 

**The Design and Simulation of the** 

*Chinese Academy of Sciences, Taiyuan Shanxi* 

*Chinese Academy of Sciences, Shanghai* 

**Synthesis of Dimethyl Carbonate and** 

**the Product Separation Process Plant** 

*1State Key Laboratory of Coal Conversion, Institute of Coal Chemistry,* 

Feng Wang1, Ning Zhao1, Fukui Xiao1, Wei Wei1 and Yuhan Sun1,2

*2Low Carbon Energy Conversion Center, Shanghai Advanced Research Institute,* 

Dimethyl carbonate (DMC) has become a green and environmental benign chemical due to its multiple reactivity and widely potential usage in chemical industry1. It has been used as a substitute to replace dimethyl sulfate and methyl halides in methylation reactions and as a carbonylation agent to substitute phosgene for the production of polycarbonates and urethane polymers. It also has been evaluated to apply as non-aqueous electrolyte component in lithium rechargeable batteries. Additionally, DMC is a strong contender to help the refining industry meet the Clean Air Act specifications for oxygen in gasoline. DMC has about 3 times the oxygen content as methyl tert-butyl ether (MTBE) and its synthesis is not dependent upon FCU isobutylene yields like MTBE. DMC has a good blending octane (R + M/2 = 105), it does not phase separate in a water stream like some

Many of the properties of DMC make it a genuinely green reagent, particularly if compared to conventional alkylating agents, such as methyl halides (CH3X) and dimethyl sulfate (DMS) or to phosgene used as a methoxycarbonylating reagent. Firstly, DMC has been proved to be a nontoxic compound. Some of the toxicological properties of DMC and phosgene and DMS are compared in Table 1. Secondly, it has been classified as a flammable liquid, smells like methanol, and does not have irritating or mutagenic effects either by contact or inhalation. Therefore, it can be handled safely without the special precautions required for the poisonous and mutagenic methyl halides and DMS and the extremely toxic

The phosgene-free route for synthesis of DMC has been widely concerned by academic and industrial researchers, such as the oxidative carbonylation of methanol, the transesterification of propylene or ethylene carbonate (PC or EC), the methanolysis of urea and direct synthesis of carbon dioxide with methanol. Recently, the newly derived route of the synthesis of DMC by urea methanolysis method was considered as a novel routine for the DMC synthesis because of the advantages of easily obtained materials, moderate

alcohols do, and it is both low in toxicity and quickly biodegradable2.

phosgene. Some physicochemical properties of DMC are listed in Table 2.

**1. Introduction** 

