Below are a list of links to documents discussing gasifiers that were fielded during WW2 and earlier:
Summary of development steps of the imbert gasifier. very interesting. from publication: Generator-Jahrbuch 1942
Here's a very interesting collection of graphs for old gasifier system. the basic profile view of each shows reactor design and system component detail. this is the largest single collection i've found to date (fall, 2010)
http://www.holzgas2000.de/historisches.asp
Werner Kroll, "Der Gasgenerator", 1943. suggested by rolf uhle
The Modern Portable Gas Producer - Theory, Design, Fuels, Performance, Utilisation, And Economics. Bosworth Goldman and Clarke Jones, 1939
A Treatise on Producer Gas and Gas Producers, Samuel S. Wyer, 1907
A_Treatise_on_Producer_gas_and_Gas_Producers.pdf
The following are links to fielded post WW2 gasifier designs:
The following paper is the test results of work done by Professor Richard Hill of the University of Maine at Orono from 1977-1979 under a Department of Energy contract.
from the german site: s www.kraft-by-gas.de.vu
Unfortunately, today there is no literature on gas generators in the trade. Um Informationen zu erhalten muß man auf alte Bücher zurückgreifen. To get information you need to fall back on old books. Hier werden Bücher vorstellen die über das Thema handeln. Books will be here to introduce the act on the issue. Diese Bücher sind nicht mehr im Handel erhältlich. These books are no longer commercially available.
Der Gasgenerator; Ing. Werner Kroll; Verlag G. Kliemt, Nossen i. Sa. - Berlin; 1943 The gas generator; Ing Werner Kroll, Verlag G. Kliemt, Nossen i. Sa - Berlin 1943
Generator Jahrbuch 1942; div. Schriftsteller; Joh. Kasper & CO., Berlin, Verlag für Kultur, Politik und Wirtschaft; 1943 Generator Yearbook 1942; various writers; Kasper & CO. John, Berlin, publisher of culture, politics and economy; 1943
Einbauanweisung für Generatoranlagen in den 1 1/2 Tonner Opel Lastkraftwagen; Adam Opel AG, Rüsselsheim am Main;1947 Installation instructions for generator installations in the 1 1 / 2 ton trucks Opel, Adam Opel AG, Rüsselsheim am Main in 1947
Allgeimene Einbauanleitung für Imbert-Fahrzeug-Anlagen; Dipl.-Ing. Allgeimene instructions for Imbert-vehicle systems, Dipl.-Ing. Hugo Buscher und Ing. A. Schuppert; Imbert -Generatoren GMBH, Köln Hugo Buscher and Ing A. Schuppert, Imbert-Generators GMBH, Cologne
Behandlung und Instandsetzung von Fahrzeug Gaserzeugeranlagen; Heinz Fiebelkorn; Verlag Wilhelm Knapp, Halle (Saale); 1948 Treatment and repair of vehicle gas producer plants; Heinz Fiebelkorn, Verlag Wilhelm Knapp, Halle (Saale), 1948
Das Generator-Taschenbuch; Ing. Werner Kroll; Alfred H. Linde Verlag, Berlin-Halensee; 1947 The generator Paperback; Ing Werner Kroll, Alfred H. Linde Verlag, Berlin-Halensee in 1947
Kleine Winke für den Generatorfahrer; Ing. Werner Kroll; Alfred H. Linde Verlag, Berlin-Halensee;1947 Small angle for the generator driver; Ing Werner Kroll, Alfred H. Linde Verlag, Berlin-Halensee in 1947
Die elektrische Ausrüstung des Gasfahrzeuges; Ing. Werner Kroll; Alfred H. Linde Verlag, Berlin-Halensee;1947 The electrical equipment of the gas vehicle; Ing Werner Kroll, Alfred H. Linde Verlag, Berlin-Halensee in 1947
Fahrzeug-Diesel-Motoren und Fahrzeug-Gas-Generatoren; Heinz Fiebelkorn; Verlag von Ernst Heinrich Moritz (Ing. Franz Mittelbach) Stuttgart; 1936 Vehicle diesel engines and vehicle gas generators, Heinz Fiebelkorn, Verlag von Ernst Heinrich Moritz (Franz Mittelbach) Stuttgart in 1936
Der kleine "Peter", Band 25, Fahrzeug-Gaserzeuger in Frage und Antwort; Dipl.-Ing. The little "Peter", Volume 25, vehicle-gas producer in question and answer, Dipl.-Ing. W. Thoelz; Verlag Richard Carl Schmidt & Co. Berlin; 1942 W. Thoelz; Publisher Richard Carl Schmidt & Co. Berlin in 1942
Autotechnische Bibliothek 98, Kraftwagen-Gaserzeuger für feste Kraftstoffe, 3.Auflage; Dipl.-Ing. W. Car Technical Library 98, cars-gas generator for solid fuels, 3rd edition, Dipl.-Ing W.. Thoelz; Verlag Richard Carl Schmidt & Co. Berlin; 1943 Thoelz; Publisher Richard Carl Schmidt & Co. Berlin, 1943
Die oben genannten Bücher sind in meinen Besitz. The above books are in my possession.