Material and Heat Integration of the Two Processes

Ethanol can be dehvered in gaseous phase to the ethylene reactors in the combined process. Thereby, the cooling demand in the rectifier column is decreased by approximately 14.3 MW, while the demand for preheating the ethanol feed to the dehydration reactor (approx. 4.3 MW) is eliminated, and the heating demand in the furnace of the ethylene plant is decreased by approximately 8.7 MW. Detailed stream data of the combined process is given in Table 4.A.3. 

The cogeneration potential is affected by the reduction of hot utility demand. As the minimum hot utility demand is reduced, the steam production in the CHP plant is reduced which consequently reduces the electricity production (which is estimated at 46 MW ). The electricity demand of the combined processes is estimated at 38 MW. Accordingly, material and heat integration of the two processes results in an excess electricity production of 8 MW j. 123 MW of excess solid residues is available after fuelling the cogeneration unit. 

4 Integration Opportunities with the Existing Chemical Cluster 

This steam is supplied by a CHP plant fired with solid residues from the ethanol process resulting in an excess of 13.3 MW (process electricity demand= 38MW, electricity produced in CHP turbine = 51.3MW). 102.5MW of solid residues can be exported from the plant. 

The increased heating and cooling demand compared to results from the pinch analysis study (see Section 3.3) is due to the fact that pinch analysis assumes direct heat exchange between process streams with a constant of lOK, whereas heat recovery through the utility system requires a higher temperature difference (AT between source profile and 

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Material and heat integration of the two processes potentially allows 49 MW of heat to be saved, corresponding to approximately 37% of the combined minimum heating demands (112MW + 19MW = 131MW). The cooling demand could be reduced by 28% compared... 

Figure 4.4 Illustration of the heat integration approach. Upper left base case with no integration between ethanol and ethylene process. Upper right heat and material integration between the two processes. Lower heat and material integration and design of a utility system to enable site-wide heat integration...

Ceramic foils are produced continuously by tape-casting methods. These ceramic tapes consist of an organic binder and oxide powder material, for example, zirconia, titania or alumina. If it is possible to integrate the production process of a micro structured reactor into such a continuous process, production costs would decrease strongly. An early approach used unstructured ceramic foils to build up a micro reactor [159], The reactor consisted essentially of two functional layers, a reaction layer and a heating layer (Figure 4.102). 

Two emerging trends endorse the concept of heat-integrated processes first, the production of basic chemicals is moved close to oil and gas wells where crude oil or natural gas is processed in large stand-alone units [1]. Second, fuel cell systems require on-site and on-demand hydrogen production from primary fuels (i.e., natural gas, liquid hydrocarbons or alcohols) [2]. Net heat generation in these processes is equivalent to raw material and energy loss, and is therefore undesirable. 

Some erasable materials contain the polymer as an integral part of the record and erase process. Figure 1.39 depicts such a system consisting of two polymer layers called the expansion and retention layer. The expansion layer is an elastomer containing a dye sensitive to light at 840 nm. The retention layer contains a dye sensitive to light at 780 nm. In the write operation, the system is exposed to an 840-nm diode laser that heats the expansion layer, thus causing it to expand and deform the retention layer. 

It may be observed that the two inner layers, Reactor and Separations, define the material balance envelope. Moreover, these define the basic structure of the flowsheet also, which is the object of a design activity named Process Synthesis. The outer layers of Heat Recovery and Utility systems deal with the heat balance envelope. Both are objects of a design activity that was called Process Integration. 

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