摘要:

AbstractCrystallization from solution. In general the processes occurring in crystallizers have previously been treated in only summary and phenomenological manner because only little was known about the joint action of the individual steps. An attempt has therefore been made, in the present survey, to examine the relationship between the physico‐chemical properties of the relevant system, the process chosen, and engineering economic

ISSN:0009-286X    

DOI:10.1002/cite.330520702

出版商:WILEY‐VCH Verlag    

年代:1980

数据来源: WILEY

ISSN:0009-286X    

DOI:10.1002/cite.330520703

出版商:WILEY‐VCH Verlag    

年代:1980

数据来源: WILEY

摘要:

AbstractFractional crystallization. The operations of fractional crystallization, comprising at least a single crystallizing and remelting (redissolution) step, differ from each other in the number of the realized theoretical stages and the method of separating the crystallisate and residual melt or mother liquor. Fractional crystallization from solutions resemble liquid‐liquid extraction, but fractional crystallization from melts is similar to rectification. There is a choice between operations with a series of temperature‐controlled vessels and counter‐current operations. Many fractional crystallizers are purifiers for high qualities; crystals generally exist only within them appa

ISSN:0009-286X    

DOI:10.1002/cite.330520704

出版商:WILEY‐VCH Verlag    

年代:1980

数据来源: WILEY

摘要:

AbstractCrystallization from melts. Equipment for crystallization from melts differs considerably from the solution crystallizer. The article discusses: Trough crystallizers, belt crystallizers, pastillators, flakers, screw crystallizers, and prilling towers. The kinetics of melt crystallization is simpler than that from solution, and the secondary nucleation becomes less important. Environmentally, crystallization from melts is more attractive because absence of solvent obviates waste products. Dust problems are avoidable by flaking, pastillizing, and prilling.

ISSN:0009-286X    

DOI:10.1002/cite.330520705

出版商:WILEY‐VCH Verlag    

年代:1980

数据来源: WILEY

摘要:

AbstractIncrustation problems – causes. Some qualitative data on incrustation in crystallizers are presented. One is still far from being able to give a general quantitative description of the incrustation process. The mathematical approaches given in this article are of an approximate nature but are useful for a qualitative assessment of parts of the problems met with. Laboratory investigations on authentic samples cannot, however, be circumvente

ISSN:0009-286X    

DOI:10.1002/cite.330520706

出版商:WILEY‐VCH Verlag    

年代:1980

数据来源: WILEY

ISSN:0009-286X    

DOI:10.1002/cite.330520707

出版商:WILEY‐VCH Verlag    

年代:1980

数据来源: WILEY

摘要:

AbstractCatalytic production of sugar alcohols (polyols) and their application. The article surveys the numerous applications of the principal sugar alcohols sorbitol and xylitol and their world production in 1978. Nowadays, the industrial production of sugar alcohols is almost exclusively by catalytic hydrogenation of the corresponding sugars; thus sorbitol is manufactured by hydrogenation of D‐glucose, xylitol by hydrogenation of xylose, and mannitol by hydrogenation of invert sugar or fructose. Some 80% of the world production of sugar alcohols are manufactured in batch suspension processes using Raney nickel catalysts. Apart from the Atlas Powder continuous suspension process employing nickel‐carrier catalysts, continuous processes have recently been developed which use Raney nickel and prove more economical owing to the lower catalyst costs. Trickling processes with fixed catalyst continue to play a minor role. Available production capacity based on batch suspension processes can be expanded by process optimization and new catalyst developments. A newly developed special Raney nickel catalyst reduces the specific catalyst consumption by about

ISSN:0009-286X    

DOI:10.1002/cite.330520708

出版商:WILEY‐VCH Verlag    

年代:1980

数据来源: WILEY

ISSN:0009-286X    

DOI:10.1002/cite.330520709

出版商:WILEY‐VCH Verlag    

年代:1980

数据来源: WILEY

ISSN:0009-286X    

DOI:10.1002/cite.330520710

出版商:WILEY‐VCH Verlag    

年代:1980

数据来源: WILEY

ISSN:0009-286X    

DOI:10.1002/cite.330520711

出版商:WILEY‐VCH Verlag    

年代:1980

数据来源: WILEY