(US4803054-A)      A reaction appts. comprises a heat exchange medium store having a well casing lining a vertical subterranean shaft defining an elongate chamber of upper and lower portions. A thermally insulated elongate conduit extends into the lower portion to supply it with heat exchanger. An elongate reaction vessel is disposed in the chamber and is spaced from the insulated conduit and is supplied by two pipe portions in heat exchange relation to each other. Fluid contg. at least two reactants is supplied to the reaction vessel to form a third column at a set pressure while heat exchanger circulates to control the reaction. A depth of 5000ft. may be used.    USE -   For aq.-phase municipal waste oxidn.    (17pp)    (DE3872549-G)      Reaction appts. has an elongate encasement with a closed end and an elongate conduit arranged in the chamber formed by the encasement to convey heat exchange fluid toward the closed end. An elongate reaction vessel is arranged in the chamber, spaced from the conduit, and has first and second pipe portions defining first and second communicating flow passages which are in heat exchange relation with one another. A fluid containing at least two reactants is introduced into the reaction vessel.    Heat exchange medium is cycled through the chamber via the conduit in heat exchange relation with the reaction vessel to control a    (JP94098304-B2)      Reaction appts. has an elongate encasement with a closed end and an elongate conduit arranged in the chamber formed by the encasement to convey heat exchange fluid toward the closed end. An elongate reaction vessel is arranged in the chamber, spaced from the conduit, and has first and second pipe portions defining first and second communicating flow passages which are in heat exchange relation with one another. A fluid contg. at least two reactants is introduced into the reaction vessel. Heat exchange medium is cycled through the chamber via the conduit in heat exchange relation with the reaction vessel to control a chemical reaction therein.    USE/ADVANTAGE -   Used partic. in large scale, aq. phase oxidn. of municipal wastes. Provides a low profile subterranean reaction appts. which can process a large quantity of reactants and in which precise control of reaction temps. can be attained.