Gas-liquid heat exchanger

The utility model discloses a gas-liquid heat exchanger, particularly a gas-liquid heat exchanger for gas preheating, and belongs to the technical field of heat exchange equipment. A pass partition plate is arranged in the middle of a gas-liquid heat exchanger shell to divide the shell into a first shell pass and a second shell pass; tube array bundles formed by arrangement of tube arrays are arranged in the first shell pass and the second shell pass; fins are spirally arranged on the surfaces of the tube arrays. The gas-liquid heat exchanger disclosed by the utility model adopts double-tube-pass double-shell-pass structure design, adopts the tube arrays of which the surfaces are provided with the spirally arranged fin structures and has the advantage that the problem of low heat exchange efficiency caused by large difference of heat exchange coefficients of gas and thermal fluid water is solved; moreover, by bypass baffle design, spaces between the tube array bundles and the shell and spaces between the tube array bundles and the pass partition plate are blocked and all gas flow is guaranteed to pass through spaces in the tube array bundles, so that heat transfer efficiency is further improved.