37 Construction of ethanol plants; installation of equipment and machines in ethanol plants for use in the production and processing of ethanol; consultation services in the field of construction of ethanol plants; installation, maintenance, repair, servicing, retrofit, and replacement of biorefinery products, namely, oil centrifuges, machines for flaking larger starch particles into smaller starch particles; machines for separating starch away from fiber protein, or fats; machines for fiber separation or removal; machines for removing suspended solids from thin stillage stream during production and processing of ethanol; machines for separating crude protein from a process stream during production and processing of ethanol; animal feed drying machines; machines for converting solid waste to energy